A Neurosurgeon & a Neurologist .. What's the diffrence ?

Neurosurgeons treat conditions caused by accident or injury, as well as illness.

Diseases, injuries and disorders of the brain and nervous system are some of the most wide-ranging and difficult to treat in all of medicine. Neurological conditions can impair learning or mental function, affect balance and mobility, alter a patient's personality or cause debilitating, long-term pain. These conditions are treated by physicians in two closely related specialties, neurology and neurosurgery.

Neurologists

Neurologists specialize in the diagnosis and treatment of diseases or conditions occurring in the brain and nervous system, as well as their supporting systems and tissues. Some focus on neurophysiology, using diagnostic tests such as electroencephalograms and electromyography to detect neurological conditions. Others specialize in the treatment of neurodevelopmental disorders, attempting to manage cerebral palsy, learning disabilities and similar chronic conditions. Neurologists might also specialize in pain management, treating patients with debilitating chronic pain or acute short-term pain. Vascular neurologists study and treat conditions of the circulatory system that affect the function of the brain or nerves.

Neurosurgeons

Neurosurgeons use a variety of therapies, from endoscopic microsurgery to radiation to traditional open surgery, to treat neurological conditions. These include traumas of the brain and spine, tumors, strokes and aneurysms, and many other conditions of the spine, brain and skull base areas. These are complex areas of practice, and neurosurgeons' work often overlaps with that of neurologists, orthopedic surgeons, and plastic or reconstructive surgeons. Often, several of these practitioners will work collaboratively with a single patient to ensure a successful outcome in complex procedures.

Similarities and Differences

Neurosurgery is closely aligned with neurology, and both require an in-depth understanding of the nervous system and its functions. Conditions that require management, or can be improved by medications or other therapies, are generally treated by neurologists. Neurologists are also more likely to act as diagnosticians, isolating and defining neurological conditions for neurosurgeons to rectify. When diagnosis reveals a physical cause for neurological conditions, neurosurgeons can usually perform a surgical procedure to remove or correct that condition, often bringing about a dramatic improvement in the patient's condition. Both neurologists and neurosurgeons can use minimally invasive endoscopic or catheter-based procedures, using miniature instruments to repair or reinforce blood vessels in the brain.

Income

One key difference between neurology and neurological surgery is income. Neurosurgeons out-earn their neurologist peers by a substantial margin, beginning in their first year of practice. Medical recruiting firm Profiles, which specializes in new physicians, reports a median first-year income of $190,000 for neurologists, while neurosurgeons starting practice earned a median income of $395,000 a year. Across all career stages, the American Medical Group Association reported a median income of $236,500 for neurologists and $592,811 per year for neurosurgeons. Staffing firm Jackson and Coker found an even broader disparity, reporting an average salary of $209,394 for neurologists but $671,086 per year for neurological surgeons.

Craniopharyngiomas Surgery

Background

Craniopharyngiomas are benign epithelial tumors of the sellar region but can have significant neurological and endocrinological consequences and may require treatment that will cause further morbidity. The first description of a craniopharyngioma is credited to Zenker, who made this observation in 1857. Following this, Mott and Barrett, in 1899, documented the occurrence of these tumors and postulated that they arose from the hypophyseal duct or Rathke pouch. This was subsequently partially confirmed in 1904, when Erdheim described the tumors histologically and suggested that they arose from remnants of the Rathke duct. Finally, in 1932, Cushing introduced the term “craniopharyngioma,” which has been widely used thereafter.

Coronal MRI shows a craniopharyngioma in the suprasellar space that causes compression of the optic nerves and chiasm. 

a Critical Images slideshow, to review cases including meningiomas, glioblastomas and craniopharyngiomas, and to determine the best treatment options based on the case history and images.

History of the Procedure

Evolution of surgical treatment for craniopharyngiomas is closely related to development of the surgical techniques of sella turcica. The first surgical techniques for craniopharyngioma originated in 1891 with the first trepanation done by Selke, then the first successful transcranial approach performed by Horsley in 1907.
The progress of the surgical techniques continued with the first successful resection of craniopharyngioma through a transsphenoidal approach by Eiselsberg in 1910, which was improved by Halstead as a sublabial transsphenoidal resection in the same year. Harvey Cushing created the foundations of craniopharyngioma patient treatment with hormone replacement therapy, but also, in 1919, he developed and performed the first successful resection through the trans-lamina terminalis approach of a retrochiasmatic craniopharyngioma. Later, in 1924, he performed a transcallosal resection of a craniopharyngioma.As technology in diagnostic imaging has improved so has the surgical treatment of craniopharyngioma.

Problem

Craniopharyngiomas are benign, extra-axial, slow-growing tumors that arise from the anterior margin of the sella turcica and predominantly involve the sella and suprasellar space.They rarely metastasize but are locally invasive (typically the hypothalamus), and treatment, particularly surgical attempts at total resection, can result in significant morbidity. As craniopharyngiomas grow, they can cause significant neurological complications, including visual loss, pituitary insufficiency, and hypothalamic damage, and recurrence, both local and meningeal, is often seen and adds to patient morbidity. Malignant transformation of craniopharyngiomas is rare but has been reported after multiple recurrences and after radiation.

Epidemiology

Frequency

The incidence of newly diagnosed craniopharyngiomas is 0.13-2 persons per 100,000 population per year. Even though in some regions such as Japan and parts of Africa, craniopharyngiomas appear with a higher incidence In the United States, approximately 350 new cases of craniopharyngioma are diagnosed every year. Distribution by age is bimodal, with the peak incidence in children at aged 5-14 years and in adults at age 50-75 years. Craniopharyngiomas account for 1-3%of all brain tumors, and half of these tumors occur in childhood. Craniopharyngiomas account for 5-10% of brain tumors in children.^, No sex predilection exists, and they equally occur in males and females. No genetic relationship is currently known; however, a few familial cases have been reported in the literature.

Etiology

Although the histologic description of craniopharyngiomas was first described over a century ago, considerable debate still exists. Currently, 3 theories are widely accepted, and from these, 3 histologic variants have been derived. They are as follows:

• The embryogenetic theory suggests that the adamantinomatous type ("adamantinoma") arises from epithelial remnants of the Rathke pouch or the craniopharyngeal duct (the embryonal structure along which the eventual adenohypophysis and infundibulum migrate). Tumors can occur anywhere along the course of this duct, from the pharynx to the sella turcica and third ventricle, which partially explains the location of the tumor.
• The metaplastic theory suggests that the squamous papillary type results because of metaplasia of squamous epithelial cell rests that arise from squamous cell nests normally found at the junction of the pituitary stalk and pars distalis.
• Another theory postulates that this tumor is a midline congenital tumor not fundamentally different from an epidermoid cyst.

Pathophysiology

In the World Health Organization (WHO) classification, craniopharyngiomas are divided into 2 groups, adamantinomatous and papillary. There does not appear to be a difference in terms of prognosis, surgical resection, radiosensitivity, and life-expectancy between these groups.

Presentation

The onset of symptoms is generally insidious, with a delay of approximately 1-2 years between initial symptoms and diagnosis. The clinical presentation can include a wide range of symptoms, which depend on the location of the tumor and involvement of adjacent structures. Headache is the most common presenting symptom, followed by endocrine deficiencies and visual disturbances. Headache is usually due to either the tumor’s mass effect or hydrocephalus (from obstruction of the foramen of Monro, third ventricle, or aqueduct of Sylvius), which occurs in 15-30% of patients. This obstructive hydrocephalus may, on rare occasion, require emergent neurosurgical management.
Endocrine disturbances are related to direct compression from the tumor. Endocrine deficiency is most commonly in growth hormone (75%), followed by gonadotropin deficiency (40%), thyroid-stimulating hormone (25%), and corticotropin (25%).Growth failure can be seen in up to 93% of children with craniopharyngioma and is related to either growth hormone deficiency, hypothyroidism, or both. Adults have more varied presentation and may develop sexual or menstrual dysfunction. Eighty-eight percent of men experience decreased sex drive, while 82% of women have amenorrhea. Other endocrine dysfunction may lead to precocious puberty and obesity.
Large tumors in adults can cause psychiatric symptoms, memory loss, apathy, incontinence, depression, and hypersomnia. Long-standing cognitive deficits and profound memory loss have been reported and suggest a worse prognosis. Visual deficits are caused by compression of the optic chiasm from suprasellar tumor growth. Classically, the tumor presents as a bitemporal hemianopsia, but it may also manifest as homonymous hemianopsia, scotoma, or optic atrophy with papilledema.
Other presenting symptoms can include chemical meningitis from rupture of cyst contents into the subarachnoid space and resulting in headaches, stiff neck, and seizures.

Indications

Surgical treatment is indicated in most cases of craniopharyngioma, but surgeons have often approached this tumor with either an aggressive attempt at gross total resection of the tumor or a more conservative approach with a planned subtotal removal of the tumor followed by radiation therapy. Contemporary radiation techniques deliver radiation more accurately, thus preserving the important anatomic structures around or near the tumor.
The decision for either approach should take into consideration the anatomic localization of the tumor, size, invasion of the nearby structures, and the nature of the tumor. The most common indication for surgery is neurologic compromise from tumor mass effect. In children, hypothalamic and endocrine dysfunction may develop before visual defects are noticed. Obesity and lethargy are common in children with craniopharyngiomas. In general, any mass lesion in the pituitary sella and suprasellar area should undergo a biopsy or resection, if feasible. Radiotherapy is indicated in recurrence or in the treatment of residual tumor.

Relevant Anatomy

Craniopharyngiomas have been surgically divided into 3 groups: sellar, prechiasmatic, and retrochiasmatic. Sellar-located tumors may be suprasellar (75%), infrasellar (21%), or intrasellar (4%). These tumors occasionally grow into the third ventricle, causing hydrocephalus. The arterial supply is usually from the anterior cerebral and anterior communicating arteries or from the internal carotid and posterior communicating arteries.
Craniopharyngiomas are usually avascular on angiography but may encase or displace vessels that form the circle of Willis. Usually, the internal carotid artery (ICA) is displaced laterally, the anterior cerebral artery (ACA) is displaced anteriorly, and the basilar artery is displaced posteriorly.
A craniopharyngioma does not receive blood supply from the posterior circulation, unless it is parasitized from the floor of the third ventricle. As these tumors enlarge, they may elevate and infiltrate the optic chiasm as well as the hypothalamic region. Occasionally, they extend into the pituitary fossa or posteriorly to the ventral pons, and rarely, they invade the basal ganglia or the brain parenchyma.
When predominantly in the sella, these tumors erode the bony floor and enlarge the sella.

Contraindications

Surgery is contraindicated in patients with cardiac or respiratory abnormalities that make the risk of general anesthesia unacceptably high. Moreover, patients who take chronic anticoagulation medication must cease medication and demonstrate normal coagulation studies prior to surgery. Asymptomatic patients or those with a small tumor may be monitored with serial MRI scans. A small tumor in the pituitary region without mass effect or endocrine dysfunction may also be monitored with serial MRIs.

Laboratory Studies

Endocrine assessment

A full pituitary endocrine workup is usually mandatory. This includes evaluating the following:

• Adrenocorticotropic hormone (ACTH or corticotropin)
• Growth hormone (GH) and insulin growth factor (IGF-1)
• Cortisol
• Prolactin
• Luteinizing hormone (LH)
• Follicle-stimulating hormone (FSH)
• Thyrotropin (ie, thyroid-stimulating hormone [TSH])
• Triiodothyronine (T ₃)
• Thyroxine (T ₄).

Any abnormalities should be corrected preoperatively but, at the very least, low cortisol levels and diabetes insipidus should be treated prior to any surgical procedure.

Imaging Studies

CT and MRI are the complementary examinations of choice. Today, the best imaging tool is MRI without and with contrast enhancement.

CT scan

Craniopharyngiomas can vary greatly in size, from a few millimeters to greater than 5 cm. On CT scan, 90% are at least partially cystic, 90% have calcifications, and 90% have nodular or rim enhancement. These tumors are heterogeneous, with the cystic component being hypodense on CT scan and the solid component being isodense or slightly hyperdense with variable enhancement with contrast.

MRI

An MRI with and without contrast is the preferred sequence of choice. On T1-weighted images, the cystic component is often hyperintense and the solid component is isointense, with enhancement of the rim or tumor nodule. On T2-weighted images, the cystic component is hyperintense, as is the solid component.
In the immediate postoperative period (within the first 48 hr), a contrast-enhanced MRI is usually performed to determine whether residual tumor is present, as well as to establish a baseline for future follow-up.

Other Tests

Ophthalmology assessment

Visual acuity and visual field assessment is required to delineate any deficit, including papilledema.

Histologic Findings

Craniopharyngiomas are usually composed of both solid and cystic components. Cyst walls may vary from thin membranes to thick, tough structures that may be hard and rigid because of calcifications. The interior is lined with stratified squamous epithelium with pearly keratin formations. The outside layer is columnar epithelium on a collagenous basement membrane. Calcifications are common; 90% of tumors in children have calcifications, as do 40% of these tumors in adults. Inside the tumor, fibrous tissue, necrotic debris, cholesterol clefts, and keratin pearls are commonly found.
The following 3 histologic phenotypes are seen in craniopharyngioma:

• Adamantinomatous tumors (seen predominantly in children) resemble enamel-forming oropharyngeal neoplasms. The classic appearance is that of a cystic tumor, usually with a solid component. The cyst may contain fluid that can vary in color, but it usually has a tan appearance that is classically described as resembling “motor oil.” Extensive fibrosis and inflammation have also been observed, which result in dense adhesions between the mass and vasculature, a phenomenon that further contributes to the difficulty in resecting craniopharyngiomas.
• Squamous papillary tumors (seen predominantly in adults) generally involve only a solid component, which is typically seen without calcifications. It is frequently located in the third ventricle and is usually more encapsulated than the other types and, thus, more easily resectable.
• Mixed tumors are a combination of the adamantinomatous and papillary forms.

Craniopharyngiomas are known to not undergo malignant degeneration and are usually well defined.However, at the tumor margins, the epithelial fronds tend to penetrate deep into the brain tissue. This may cause a glial reaction in the surrounding brain, making complete resection difficult and possibly predisposing this tissue to traction injuries, particularly in the hypothalamus. The characteristic location of these tumors in the sellar and parasellar region, together with the different histologic subtypes, allows for the above theories that may explain the origin of these tumors.

Medical Therapy

No primary medical therapy exists for this tumor. Hormonal replacements are administered as needed if endocrine abnormalities exist.

Surgical Therapy

The initial surgical decision concerns the approach. If the predominant portion of the tumor is intrasellar, the approach is usually transsphenoidal. Often, the suprasellar component can be delivered into the sella and evacuated. Further, the transsphenoidal approach is well tolerated by patients and is preferable to a craniotomy, when feasible.
If the pituitary sella is not enlarged, the transsphenoidal approach is generally not preferred. A craniotomy is usually necessary when the predominant component is suprasellar, although certain suprasellar masses may be located through an extended transsphenoidal approach. New technology in optics and instrumentation has now permitted many transsphenoidal procedures to be done exclusively through the endoscope. Specialized training is needed in these techniques, but in some instances, even large tumors in the suprasellar space can be safely removed or debulked.
The pterional craniotomy is the standard craniotomy approach to suprasellar lesions because it allows good visualization of the optic nerves, chiasm, and surrounding structures. Variations of the pterional craniotomy have been proposed to include resection of the orbital rim and zygoma so as to provide a more defined view of the skull base and thereby allow better access to the superior aspects of this tumor. These approaches lend themselves to less frontal lobe retraction in order to visualize the operative site.
A subfrontal approach is appropriate for lesions that lie anterior to the optic chiasm, but this may be difficult to determine preoperatively. Under rare circumstances, a transcallosal approach is necessary when the tumor is entirely within the third ventricle. The drawback to this approach is the inability to identify the optic chiasm and pituitary stalk early in the dissection.
Cystic tumors are amenable to either a transsphenoidal approach or a pterional craniotomy. The solid components often adhere to the optic chiasm or hypothalamus and, therefore, may be difficult to remove in their entirety.
Cyst aspiration combined with intracavitary phosphorus-32 (³² P) instillation is an alternative to traditional surgical resection (see video below). Good long-term control of tumor growth has been demonstrated; however, a tumor with significant solid components is not likely to respond to(³²P) .Intracystic chemotherapy with bleomycin has also been tried, with some success in short-term reduction of cyst size.Intracavitary therapy requires that an Ommaya reservoir be placed into the cyst. Care needs to be taken that the catheter tip openings are in the cyst itself and that there is no spillage of cyst contents or injected material outside the cyst wall.

Dissection of craniopharyngioma cyst with aspiration.

Grading

In an attempt to balance the advantages of an aggressive surgical resection against the risk of significant morbidity, a preoperative grading system (for children) has been proposed. This system considers the extent of invasion of the hypothalamus by the tumor and is as follows:

• Type 0: The tumor represents no hypothalamic involvement.
• Type 1: The tumor distorts or elevates the hypothalamus, but the latter is still visible.
• Type 2: The hypothalamus is no longer visible.

Consequently, some proposed that a gross total resection be attempted in type 0 and type 1 tumors and that a subtotal resection be attempted in a type 2 tumor, leaving only the hypothalamic component. Although this grading system was developed in a pediatric population, applying it to an adult population is certainly feasible. Some evidence exists, however, that the craniopharyngiomas that arise in adults are less likely to invade the hypothalamus.
A newer classification system proposed by Kassam et al uses a scheme that divides tumors according to their suprasellar extension, based upon the endoscopic expanded endonasal approach (EEA), and is as follows:

• Type I - Preinfundibular
• Type II - Transinfundibular (extending into the stalk)
• Type III - Retroinfundibular, extending behind the gland and stalk, and has 2 subdivisions (IIIa, extending into the third ventricle; and IIIb, extending into the interpeduncular cistern)
• Type IV - Isolated to the third ventricle and/or optic recess and is not accessible via an endonasal approach

Radiation therapy

Radiation is indicated in patients who had a subtotal resection of craniopharyngioma or with recurrence of the disease. Types of radiation therapy include stereotactic radiosurgery (SRS) and fractionated external beam radiation therapy.

Stereotactic techniques (SRS) are based on localization of the target through stereotactic frame coordinates (attached to the head as in Gamma Knife) or non–frame-based techniques (CyberKnife). Small tumors can be treated with a single fraction of radiation that delivers a high dose of radiation with rapid falloff to minimize the dose to surrounding structures. A larger target volume or proximity to the optic nerve and chiasm may require use of fractionated SRS techniques designed to minimize damage to healthy structures. The dose delivered is usually limited by the optic chiasm, which ideally should receive less than 10 Gy.
External beam radiation therapy uses 3-dimensional planning to deliver radiation with a margin around the tumor. Up to 30 fractions may be used to deliver an effective total dose while keeping daily doses low. Recurrence of tumor is higher when total dose is less than 54 Gy, while complications increase with doses greater than 62 Gy.
Recent data support the concept of subtotal resection followed by radiation therapy as an effective therapy equal in outcome to gross total resection but with fewer complications.

Sagittal MRI shows a cystic craniopharyngioma in the suprasellar space with extension into the third ventricle.

Preoperative Details

Preoperative workup includes an endocrinologic evaluation, particularly to exclude hypoadrenalism and hypothyroidism, both of which increase surgical mortality rates. Dexamethasone may be started prior to surgery to decrease edema.

Intraoperative Details

Successful transsphenoidal resection of a craniopharyngioma requires a generous removal of the contents of the sella turcica. Adequate suprasellar decompression occurs when the arachnoid membrane that surrounds the tumor descends into the operative field. Cerebrospinal fluid (CSF) leakage occurs if the arachnoid is disrupted.
The goal of a craniotomy is gross total removal of the tumor with preservation of the optic apparatus and pituitary stalk. Understanding the anatomy in this region is key to accomplishing this goal. The optic chiasm is nearly always elevated, and the pituitary stalk is usually displaced posteriorly. The stalk may be identified by the striate pattern of portal vessels along its surface. The lamina terminalis may need to be opened for access into the third ventricle. The goal of tumor removal must not outweigh the need for preservation of neural structures; therefore, leaving undisturbed a tumor that is densely adherent to the optic apparatus, anterior cerebral artery, or hypothalamus is advisable.
In general, because long-term tumor control is excellent with radiation therapy following subtotal tumor removal, a conservative approach to tumor resection is usually advised.In some patients, however, a good cleavage plane exists between tumor and brain, and a true complete resection can be accomplished. Surgical judgment is crucial in the assessment of this possibility.

Follow-up

Performing a full postoperative endocrine evaluation as well as repeated imaging studies is advisable. MRI scans are typically obtained immediately postoperatively (within 48 h), at approximately 3 months, and annually thereafter. Long-term follow-up also includes visual-field and pituitary hormone testing.

Complications

The most common complications are related to injury of the adjacent neural structures. Vision may worsen because of unavoidable optic apparatus manipulation.
Postoperatively, many patients demonstrate hypopituitarism. In order to offset this, they are usually given physiologic doses of hydrocortisone as well as a dexamethasone taper to decrease the edema associated with the surgical approach.
Diabetes insipidus may develop and may require treatment with fluid replacement and, occasionally, vasopressin or its synthetic analogue, desmopressin. Some patients have diabetes insipidus as well as disruption of their thirst sensation. These patients pose a difficult management problem and are at high risk for developing hypernatremia. Injuries to the hypothalamus can cause other behavioral changes, including caloric balance disturbance, memory disturbance, and changes in affective behavior.
In rare cases, development of radiation-induced gliomas may occur. This long-term complication has a latency period of greater than 10 years, frequently involves the temporal lobe, and has been predominantly reported in patients who underwent conventional fractionated radiotherapy in their childhood.

Axial MRI shows a craniopharyngioma cyst that contains proteinaceous fluid in the third ventricle. The cyst fluid appears hyperintense.

Outcome and Prognosis

Total resection is the best chance for cure, although some series have reported good results with subtotal resection and fractionated radiation therapy. Small residual tumor, confirmed on postoperative MRI, is generally treated with external beam radiotherapy; however, stereotactic radiosurgery has been used. The use of proton beam radiotherapy for residual disease is currently being investigated. Although the amount of radiation is limited by the proximity to the optic chiasm, good long-term results are now being reported after radiosurgery.
Adverse effects of radiation therapy include endocrine dysfunction, optic neuritis, dementia, and radiation necrosis. In addition, radiation can induce tumors such as meningiomas, sarcomas, and gliomas. In pediatric cases, radiation is postponed to minimize its effects on intelligence quotient and growth. Survival rates for patients with surgery and radiation are better than with surgery alone because radiation helps deter regrowth when residual tumor is present.
Brachytherapy has also been used to treat cystic craniopharyngiomas. Radioisotopes are placed into the cystic portions of the craniopharyngioma. Phosphorus-32 (³² P), colloidal gold-198, colloidal yttrium-91, and bleomycin have all been used. Bleomycin causes shrinkage of the cyst but is highly toxic to neural structures.
In a review of brachytherapy for craniopharyngiomas, Van den Berge followed 31 patients for an average of 41 months.Twenty-nine percent showed improvement of visual acuity, while 13% had stable visual acuity, and 58% deteriorated. Similarly, 28% showed improvement of their visual fields, with 20% showing no change, and 52% deteriorating.

Mortality and morbidity

Overall, the surgical mortality rate is less than 5%, mostly from hypothalamic injury. Bilateral hypothalamic injuries lead to hyperthermia and somnolence. The 10-year survival rate, excluding non–tumor-related deaths, is 90%.
The recurrence of craniopharyngiomas is reported to be up to 24% with approximately a 7-year follow-up. The main risk factor for recurrence is the presence of the residual tumor. Tumor recurrence is higher in the first 3 years after surgery.
In patients with gross total removal of a craniopharyngioma, the 5-year recurrence-free rate is 84.9%, compared to 48.3% in patients with subtotal removal.Morbidity and mortality rates are higher with recurrence and mainly present as visual deficits, endocrine abnormalities, hypothalamic injury, and neurocognitive and neurobehavioral deficits.The visual impairment can be caused by direct damage during surgery or from a daily dose of radiation greater than 2 Gy. The cumulative probability for visual deficits after surgery/radiation is reported to be 36-48% with a 10-year follow-up.
Endocrine abnormalities are commonly seen in postoperative patients with craniopharyngioma. It presents as hypopituitarism and is reported with deficiencies of at least 3 pituitary hormones in 54-100%.Preoperative endocrine deficits do not improve after the surgery, although patients with diabetes insipidus may improve.Hypothalamic dysfunction after the surgery may present as obesity because of hyperphagia, water balance impairment, loss of temperature control, sleep disorders, and neurocognitive disorders. Hypothalamic damage may result from tumor invasion, direct surgical damage from the resection of adherent tumor, tumor recurrence, and radiation.
Hoffman followed 50 children with craniopharyngiomas.In his 1992 report, 90% had total excision, and tumor recurred in 34%. Of all 50 children, 56% were leading normal or nearly normal lives, often requiring endocrine replacement. Twenty-four percent were able to function reasonably well and to attend school despite intellectual, visual, or weight problems; 8% were significantly handicapped; and 6% died. Effenterre et al reported that failure to achieve an independent living function with poor integration and performance at work or school is seen in 16% of adults and 26% of children.The data from literature show the importance of preoperative planning with a reasonable decision in terms of maximal safe tumor resection and the avoidance of complications.

Future and Controversies

The largest divide in the treatment of craniopharyngiomas regards whether to perform a gross total excision or perform a subtotal resection followed by radiation therapy. Retrospective series support both philosophies. Surgical judgment must temper the enthusiasm for gross total removal at all costs. The use of 3-dimensional conformal radiation treatment (3D CRT), stereotactic radiosurgery (SRS), stereotactic radiotherapy (SRT), and intensity-modulated radiation therapy (IMRT) will further allow treatment of small tumor residua with little risk of neurologic deficit. The development of endoscopic techniques has placed greater emphasis on minimally invasive approaches, but this should not detract from surgical techniques that the surgeon feels most comfortable using.

Tension Muscle Contraction Headaches

Background

Tension-type headache (TTH) represents one of the most costly diseases because of its very high prevalence. TTH is the most common type of headache, and it is classified as episodic (ETTH) or chronic (CTTH). It had various ill-defined names in the past including tension headache, stress headache, muscle contraction headache, psychomyogenic headache, ordinary headache, and psychogenic headache.

The International Headache Society (IHS) defines TTH more precisely and differentiates between the episodic and the chronic types. The following is a modified outline of the IHS diagnostic criteria:

Episodic tension-type headache

See the list below:

• At least 10 previous headaches fulfilling the following criteria; number of days with such headache fewer than 15 per month
• Headaches lasting from 30 minutes to 7 days
• At least 2 of the following pain characteristics:
  

  • Pressing/tightening (nonpulsating) quality
  • Mild or moderate intensity (may inhibit but does not prohibit activities)
  • Bilateral location
  • No aggravation from climbing stairs or similar routine physical activity
• Both of the following:
  

  • No nausea or vomiting
  • Photophobia and phonophobia absent or only one present
• Secondary headache types not suggested or confirmed

Chronic tension-type headache

See the list below:

• Average headache frequency of more than 15 days per month for more than 6 months fulfilling the following criteria
• At least 2 of the following pain characteristics:
  

  • Pressing/tightening (nonpulsating) quality
  • Mild or moderate intensity (may inhibit but does not prohibit activities)
  • Bilateral location
  • No aggravation from climbing stairs or similar routine physical activity
• Both of the following:
  

  • No vomiting
  • No more than one of the following: nausea, photophobia, or phonophobia
• Secondary headache types not suggested or confirmed

Pathophysiology

Pathogenesis of TTH is complex and multifactorial, with contributions from both central and peripheral factors. In the past, various mechanisms including vascular, muscular (ie, constant overcontraction of scalp muscles), and psychogenic factors were suggested. The more likely cause of these headaches is believed now to be abnormal neuronal sensitivity and pain facilitation, not abnormal muscle contraction.

Various evidence suggests that, like migraine, TTH is associated with exteroceptive suppression (ES2), abnormal platelet serotonin, and decreased cerebrospinal fluid beta-endorphin. In one study, plasma levels of substance P, neuropeptide Y, and vasoactive intestinal peptide were found to be normal in patients with CTTH and unrelated to the headache state.

Several concurrent pathophysiologic mechanisms may be responsible for TTH; according to Jensen, extracranial myofascial nociception is one of them. Headache is not related directly to muscle contraction, and possible hypersensitivity of neurons in the trigeminal nucleus caudalis has been suggested.

Bendtsen described central sensitization at the level of the spinal dorsal horn/trigeminal nucleus due to prolonged nociceptive inputs from pericranial myofascial tissues.The central neuroplastic changes may affect regulation of peripheral mechanisms and can lead to increased pericranial muscle activity or release of neurotransmitters in myofascial tissues. This central sensitization may be maintained even after the initial eliciting factors have been normalized, resulting in conversion of ETTH into CTTH.

Further research is necessary to understand and clarify the mechanisms of TTH. Research may lead to the development of more specific and effective management in the future.

Epidemiology

Frequency

United States
TTH is the most common primary headache syndrome.

International

Rasmussen et al reported a lifetime prevalence of TTH of 69% in men and 88% in women in the Danish population.The patient may experience more than one primary headache syndrome. In one study by Ulrich et al, the 1-year prevalence of TTH was the same among individuals with and without migraine.

Sex

Women are slightly more likely to be affected than men.

• The female-to-male ratio for TTH is approximately 1.4:1.
• In CTTH, female preponderance is 1.9:1.

Age

TTH can occur at any age, but onset during adolescence or young adulthood is common. It can begin in childhood.

History

Tension-type headaches (TTHs) are characterized by pain that is usually mild or moderate in severity and bilateral in distribution. Unilateral pain may be experienced by 10-20% of patients. Headache is a constant, tight, pressing, or bandlike sensation in the frontal, temporal, occipital, or parietal area (with frontal and temporal regions most common).

• Ulrich et al reported that 82% of TTHs last less than 24 hours.
• The deep steady ache differs from the typical throbbing quality of migraine headache.
  • Prodrome and aura are absent.
  • Occasionally, the headache may be throbbing or unilateral, but most patients do not report photophobia, sonophobia, or nausea, which commonly are associated with migraine. 
• Some patients may have neck, jaw, or temporomandibular joint discomfort.

Physical

See the list below:

• Patients with TTH have normal findings on general and neurologic examinations.
• Some patients may have tender spots or taut bands in the pericranial or cervical muscles (trigger points).

Causes

Various precipitating factors may cause TTH in susceptible individuals. One half of patients with TTH identify stress or hunger as a precipitating factor.

• Stress - Usually occurs in the afternoon after long stressful work hours
• Sleep deprivation
• Uncomfortable stressful position and/or bad posture
• Irregular meal time (hunger)
• Eyestrain
  
  

   Differential Diagnoses

  • Aseptic Meningitis
  • Lyme Disease
  • Migraine Headache
  • Migraine Variants
  • Pseudotumor Cerebri

    Laboratory Studies

    See the list below:
    

    • The diagnosis of tension-type headache (TTH) is clinical. As with the other primary headaches, no specific diagnostic test is available for TTH.
    • Occasionally, studies may be required to exclude secondary headache disorders.

    Imaging Studies

    See the list below:
    

    • Neuroimaging studies are important to rule out secondary causes of headache, including neoplasms and cerebral hemorrhage.
    • MRI imaging shows the greatest detail of cerebral structures and is especially useful in evaluating the posterior fossa.
    • CT scan with contrast is a viable alternative but is inferior to MRI for viewing structures in the posterior fossa.
    • Neuroimaging is indicated if the headaches are atypical in any way or if they are associated with abnormalities in the neurologic examination. 

    Medical Care

    See the list below:
    

    • Management of TTH consists of pharmacotherapy, psychophysiologic therapy, and physical therapy.
      

      • Treatment of headache must be tailored for individual patients.
      • Recognition of comorbid illness is essential. Migraine may be associated with TTH, and management overlaps. Other associated conditions may include depression, anxiety, and emotional or adjustment disorders.
      • Management of CTTH with a combination of tricyclic antidepressant medication and stress management therapy may result in a better outcome than monotherapy. 

    • Pharmacotherapy consists of abortive therapy (to stop or reduce severity of the individual attack) and long-term preventive therapy. Preventive drugs are the main therapy for CTTH, but they seldom are needed for ETTH.
      

      • These headaches (especially ETTH) generally respond to simple over-the-counter (OTC) analgesics such as paracetamol (ie, acetaminophen), ibuprofen, aspirin, or naproxen.
      • If treatment is unsatisfactory, the addition of caffeine or use of prescription drugs is recommended. If possible, avoid use of barbiturates or opiate agonists.
      • Also discourage overuse of all symptomatic analgesics because of the risk of dependence, abuse, and development of chronic daily headache.
      • Fiorinal with codeine is generally significantly more effective than placebo or Fiorinal alone. The combination is also significantly better than codeine alone in relieving pain and maintaining ability to perform daily activities. However, Fiorinal with codeine is not first-line therapy and carries a significant risk of abuse.
    • Consider preventive medications if the headaches are frequent (>2 attacks per wk), of long duration (>3-4 h), or severe enough to cause significant disability or overuse of abortive medication.
      

      • Amitriptyline (Elavil) and nortriptyline (Pamelor) are the most frequently used tricyclic antidepressants.
      • The selective serotonin reuptake inhibitors (SSRIs) fluoxetine (Prozac), paroxetine (Paxil), and sertraline (Zoloft) also are used commonly by many physicians. In a double-blind placebo-controlled trial conducted by Saper et al of fluoxetine in patients with chronic daily headache and migraine, it was reported to be helpful.
      • Other antidepressants such as doxepin, desipramine, protriptyline, and buspirone also can be used. According to Cohen, protriptyline may be comparable in effectiveness to amitriptyline in CTTH without producing drowsiness and weight gain.
      • As reported by Bendtsen et al, in one double-blind trial that compared citalopram to amitriptyline and a placebo, patients on citalopram demonstrated lower headache scores than those on placebo, but amitriptyline was significantly more effective.
      • Tizanidine may improve inhibitory function in the central nervous system and can provide pain relief. One recent study by Saper et al provides support for the efficacy of tizanidine in the prophylaxis of chronic daily headache.Currently the use of tizanidine remains investigational in the treatment of this disorder.
    • Physical therapy techniques include hot or cold applications, positioning, stretching exercises, traction, massage, ultrasound therapy, transcutaneous electrical nerve stimulation (TENS), and manipulations.
      

      • Heat, massage, and stretching can be used to alleviate excess muscle contraction and pain.
      • Cranial electrotherapy stimulation is different from TENS, is safe, and may be effective in alleviating the pain intensity of TTH. It may be considered as an alternative to long-term analgesic use.
    • Psychophysiologic therapy includes reassurance, counseling, relaxation therapy, stress management programs, and biofeedback techniques. With these modalities of treatment, both frequency and severity of chronic headache may be reduced. 
      • In a few studies, such as that by Holroyd et al, benefits from cognitive-behavioral therapy and biofeedback therapy have been reported.
      • Biofeedback may be helpful in some patients when combined with medications.
      • One prospective study of TTH in an elderly population suggested that relaxation therapy may be an effective intervention.
    • The following various minimally invasive techniques may provide pain relief:
      

      • Trigger point injections
      • Greater or lesser occipital nerve blocks
      • Auriculotemporal nerve block
      • Supraorbital nerve block
      • Botulinum toxin injection in the pericranial muscle
      • Other alternative treatments: In one study, Biondi and Portuesi suggested that acupuncture results are difficult to assess and that acupuncture should be reserved for selected patients.

    Consultations

    Psychiatry consultations: CTTH can mask or be associated with comorbid conditions such as depression, anxiety, or other serious emotional disorders.

    Diet

    Balanced meals

    Activity

    These nonpharmacologic methods have shown improvement of central nervous-system related symptoms:
    

    • Regular exercise
    • Adequate sleep: The patient should maintain a regular sleep schedule.
    • Relaxation training

      Medication Summary

      The goals of pharmacotherapy for tension-type headaches (TTHs) are to relieve the headache, reduce morbidity, and prevent complications.

      Analgesics

      Class Summary

      These agents can be used for abortive therapy.
      

      
      

      Acetaminophen (Tylenol, Aspirin Free Anacin, Feverall, Tempra)

      First choice for treatment of headache, especially during pregnancy and breastfeeding.

      Nonsteroidal anti-inflammatory drugs (NSAIDs)

      Class Summary

      These agents inhibit inflammatory reactions and pain by decreasing activity of cyclooxygenase, which is responsible for prostaglandin synthesis. They generally are used in mild to moderately severe headaches; however, they also may be effective for severe headaches.
      

      Ibuprofen (Motrin, Advil)

      First choice for treatment of headache, especially during pregnancy and breastfeeding.
      

      
      

      Naproxen sodium (Anaprox, Naprelan)

      First choice for treatment of headache, especially during pregnancy and breastfeeding.
      

      Antidepressants

      Class Summary

      These drugs increase the synaptic concentration of serotonin and/or norepinephrine in CNS by inhibiting their reuptake by the presynaptic neuronal membrane.
      Cymbalta can also be helpful for patients who have coexisting depression.
      

      
      

      Nortriptyline (Pamelor, Aventyl HCl)

      Has demonstrated effectiveness in treatment of pain.
      

      
      

      Amitriptyline (Elavil)

      Has demonstrated effectiveness in treatment of pain.

      Serotonin reuptake inhibitors

      Class Summary

      These agents specifically inhibit presynaptic reuptake of serotonin. May be considered as an alternative to TCAs.View full drug information
      

      Fluoxetine (Prozac)

      Has potent specific 5-HT uptake inhibition with fewer anticholinergic and cardiovascular adverse effects than TCAs.
      

      
      

      Sertraline (Zoloft)

      Atypical nontricyclic antidepressant with potent specific 5-HT uptake inhibition and fewer anticholinergic and cardiovascular adverse effects than TCAs.
      

      Paroxetine (Paxil)

      Atypical nontricyclic antidepressant with potent specific 5-HT uptake inhibition and fewer anticholinergic and cardiovascular adverse effects than TCAs.

      Electrolyte supplements

      Class Summary

      Electrolytes such as magnesium may help in the treatment of tension headache.
      

      
      

      Magnesium chloride (Slow-Mag, Mag-Delay)

      Magnesium metabolism may have a significant role in both the etiology and the treatment of muscle contraction tension headache.
      
      

      Patient Education

      Advise the patient with tension-type headaches (TTHs) to take the following actions:
      

      • Avoid stressful situations if possible
      • Maintain a regular sleep schedule
      • Exercise regularly
      • Eat balanced meals
      • Avoid uncomfortable stressful positions and bad posture
      • Avoid eyestrain
      • Try biofeedback and relaxation techniques

      
      
    
    

Glomus Tumors

Background

Glomus jugulare tumors are rare, slow-growing, hypervascular tumors that arise within the jugular foramen of the temporal bone. They are included in a group of tumors referred to as paragangliomas, which occur at various sites and include carotid body, glomus vagale, and glomus tympanicum tumors.


Glomus jugulare tumors occur predominantly in women in the fifth and sixth decades of life. Because of the insidious onset of symptoms, these tumors often go unnoticed, and delay in diagnosis is frequent. Because of the location and extent of involvement, glomus jugulare tumors present a significant diagnostic and management, as well as social, challenge.

Lateral view of the initial carotid arteriogram of a 20-year-old woman who presented in June 1970 with episodic hypertension, headaches, and palpitations. Urine catecholamine levels were elevated, and a pheochromocytoma was suspected. She underwent a negative exploratory laparotomy. She subsequently developed palsies of the IX, X, XI, and XII cranial nerves on the right side. A norepinephrine-secreting glomus jugulare tumor with intracranial and cervical extension was identified on radiologic and arteriographic imaging. Arrows delineate the tumor blush. The arrowhead demonstrates branch of the middle meningeal artery providing blood supply to the tumor. This branch was embolized.

History of the Procedure

The glomera jugulare, or glomus bodies, are small collections of paraganglionic tissue. They are derived from embryonic neuroepithelium in close association with the autonomic nervous system and are found in the region of the jugular bulb. In 1840, this tissue was first described by Valentin as ganglia tympanica. In 1878, Krause described the tissue as glandula tympanica. Guild was the first to note the similarity between these collections of tissue and the carotid body. He referred to them as glomus jugulare.

These structures also have been referred to as nonchromaffin paraganglia. The first description of glomus tumor as a hyperplastic glomus bodies was reported by Masson in 1924.


In 1945, Rosenwasser described the first patient diagnosed with glomus jugulare tumor.The patient survived until 1987. An association of glomus tumor with neurofibromatosis Type 1 (NF-1) has been described.
Vascular tumors of the middle ear had previously been reported, but Rosenwasser was the first to recognize the origin of these tumors from the glomus jugulare. He provided the first description of the surgical removal of a glomus jugulare tumor.

Problem

Glomus tumors of the temporal bone occur in the region of the jugular bulb and middle ear. These are rare, vascular, slow-growing tumors, and most are benign. Tumors that originate from the jugular bulb and may extend to involve the middle ear are referred to as glomus jugulare tumors.
Glomus tumors are also referred to as chemodectomas or nonchromaffin paragangliomas.

Paragangliomas are often found at other sites, including the middle ear (glomus tympanicum tumor), the carotid body (carotid body tumor), and the vagus nerve in proximity to the inferior (nodosum) vagal ganglion (glomus vagale tumor, glomus intravagale tumor). Affected sites that are much less commonly reported are the periaortic area, trachea, larynx, mandible, nose, ciliary ganglion, and fallopian canal. Optimal treatment of temporal bone glomus tumors remains controversial.

Epidemiology

Frequency

Glomus tumors occur with an estimated annual incidence of 1 case per 1.3 million people.Although rare, glomus tumors are the most common tumor of the middle ear and are second to vestibular schwannoma as the most common tumor of the temporal bone.

The female-to-male ratio is 3-6:1. Glomus jugulare tumors have also been noted to be more common on the left side, especially in females.
Most tumors occur in patients aged 40-70 years, but cases have been reported in patients as young as 6 months and as old as 88 years. Multicentric tumors are found in 3-10% of sporadic cases and in 25-50% of familial cases.

Etiology

Glomus jugulare tumors originate from the chief cells of the paraganglia, or glomus bodies, located within the wall (adventitia) of the jugular bulb, and can be associated with either the auricular branch of the vagus nerve (Arnold nerve) or the tympanic branch of the glossopharyngeal nerve (Jacobson nerve). Paraganglia are small (< 1.5 mm) masses of tissue composed of clusters of epithelioid (chief) cells within a network of capillary and precapillary caliber vessels. The number seems to increase until the fourth decade of life and then seems to decline. Paraganglia develop from the neural crest and are believed to function as chemoreceptors. Based on the presence of catecholamines and neuropeptides, paraganglia are included in the amine precursor uptake and decarboxylase (APUD) system, which has more recently been referred to as the diffuse neuroendocrine system (DNES).

Although most paragangliomas are sporadic, they can be familial with autosomal dominant inheritance and incomplete penetrance. The development of tumors in familial cases is dependent on age and on the sex of the affected parent. The nonchromaffin paragangliomas have a familial tendency. Tumors rarely occur in people younger than 18 years, and as a result of suspected genomic imprinting, only children of males possessing the disease gene develop tumors. The gene responsible for hereditary paragangliomas has been localized to band 11q23.

Pathophysiology

Glomus tumors are encapsulated, slowly growing, highly vascular, and locally invasive tumors. Sen et al described histological structure of glomus tumors as a dense matrix of connective tissue among nerve fascicles.These tumors tend to expand within the temporal bone via the pathways of least resistance, such as air cells, vascular lumens, skull base foramina, and the eustachian tube. They also invade and erode bone in a lobular fashion, but they often spare the ossicular chain.

Initially, the skull base erodes in the region of the jugular fossa and posteroinferior petrous bone, with subsequent extension to the mastoid and adjacent occipital bone (see the image below). Significant intracranial and extracranial extension may occur, as well as extension within the sigmoid and inferior petrosal sinuses. Neural infiltration is also common.

Lateral carotid arteriogram obtained 22 years after radiation therapy in a 20-year-old woman who presented in June 1970 with episodic hypertension, headaches, and palpitations.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The parenchyma of the paraganglia consists of 2 primary cell types. Type I cells are more common and are typically round with indistinct cell borders. Type II cells are smaller and irregularly shaped.
Metastases from glomus tumors occur in approximately 4% of cases.A reduction in the proportion of type II cells and a poorer staining of type I cells for s-100 and glial fibrillary acidic protein are reported to be correlated with an increased tumor grade. A metastatic lesion is distinguished from a multicentric lesion based on location. Metastases have been found in the lung, lymph nodes, liver, vertebrae, ribs, and spleen. Malignancy of the tumor probably is related to p53 and p16INK4A mutations.

Additional studies using immunohistochemical techniques revealed that malignant glomus tumors are characterized by the presence of MIB-1, p53, Bcl-2 and CD34.Up to 4% of the tumors are functional and produce clinically significant levels of catecholamines, norepinephrine, or dopamine with symptoms mimicking a pheochromocytoma. Pheochromocytoma, parathyroid adenoma, and thyroid carcinoma have been reported in association with glomus jugulare tumors.

The Glasscock-Jackson and Fisch classifications of glomus tumors are widely used. The Fisch classification of glomus tumors is based on extension of the tumor to surrounding anatomic structures and is closely related to mortality and morbidity.

• Type A tumor - Tumor limited to the middle ear cleft (glomus tympanicum)
• Type B tumor - Tumor limited to the tympanomastoid area with no infralabyrinthine compartment involvement
• Type C tumor - Tumor involving the infralabyrinthine compartment of the temporal bone and extending into the petrous apex
• Type C1 tumor - Tumor with limited involvement of the vertical portion of the carotid canal
• Type C2 tumor - Tumor invading the vertical portion of the carotid canal
• Type C3 tumor - Tumor invasion of the horizontal portion of the carotid canal
• Type D1 tumor - Tumor with an intracranial extension less than 2 cm in diameter
• Type D2 tumor - Tumor with an intracranial extension greater than 2 cm in diameter

Presentation

The clinical course of temporal bone glomus tumors reflects their slow growth and paucity of symptoms. Often, a significant delay in diagnosis occurs, and tumors may be large when first identified.

The most common symptoms are conductive hearing loss and pulsatile tinnitus. Other aural signs and symptoms are ear fullness, otorrhea, hemorrhage, bruit, and the presence of a middle ear mass. Significant ear pain is uncommon. Involvement of the inner ear produces vertigo and sensorineural hearing loss.

Cranial nerve involvement produces hoarseness and dysphagia. The presence of jugular foramen syndrome (paresis of cranial nerves IX-XI) is pathognomonic for this tumor, but it usually follows one year after the initial symptoms of hearing loss and pulsatile tinnitus. Less commonly, glomus tumors produce facial nerve palsy, hypoglossal nerve palsy, or Horner syndrome.
Headache, hydrocephalus, and elevated intracranial pressure may be produced by intracranial extension of the tumor. Ataxia and brainstem symptoms may also develop. Involvement of the dural sinuses may mimic sinus thrombosis.

In about 2-4% of cases, the first or leading symptoms are hypertension and tachycardia (pheochromocytomalike symptoms) produced by catecholamines, norepinephrine, or dopamine excreted by the tumor. Also, somatostatin, vasoactive intestinal polypeptide (VIP), calcitonin, and neuron-specific enolase may be produced by the tumor. Other related symptoms include headache, perspiration, pallor, and nausea.

Otoscopic examination reveals a characteristic, pulsatile, reddish-blue tumor behind the tympanic membrane that is often the beginning of more extensive findings (ie, the tip of the iceberg).
Audiologic examination reveals mixed conductive and sensorineural hearing loss. The sensorineural component tends to be more significant with larger tumors.

Plain skull radiography may show enlargement of the lateral jugular foramen and fossa. Axial and coronal computed tomography (CT) scanning with thin sections are superior at demonstrating the extent of bone destruction. Magnetic resonance imaging (MRI) with gadolinium-diethylenetriamine pentaacetic acid (DTPA) contrast is best for delineating tumor limits. Glomus tumors on T1- and T2-weighted MRI have characteristic soft tissue mixed intensity with intermixed high-intensity signals and signal voids (ie, salt and pepper appearance) representing fast flowing blood. A combination of CT scanning and contrast MRI is the imaging regimen of choice for glomus jugulare tumors.

Unless carotid arteriography is necessary for preoperative evaluation and/or embolization, noninvasive techniques are preferred; however, for large tumors involving the internal carotid artery (ICA), preoperative carotid arteriography with cross-compression or trial balloon occlusion is recommended. The venous drainage systems also need to be carefully studied before sinus occlusion is carried out during surgical resection.

For tumors with large intracranial extension, vertebral arteriography is advised to exclude arterial feeders from the posterior circulation.

Differential diagnoses include the following:

• Chordoma
• Otitis Media
• Eosinophilic Granuloma (Histiocytosis X)
• Meningioma
• Schwannoma
• Neurofibroma
• Chondrosarcoma
• Carcinoma (primary and metastatic)
• Cholesteatoma
• Osteoma
• Otosclerosis
• Chronic mastoiditis
• Cholesterol granuloma
• Aneurysm
• Aberrant intrapetrous internal carotid artery
• Idiopathic hemotympanum
• Arterious malformation
• Prominent jugular bulb
• Persistent stapedial artery
• Lymphoma

Indications

See Surgical therapy for specific surgical indications.

Relevant Anatomy

Most jugulotympanic paraganglia are located in the adventitia of the jugular bulb within the jugular foramen. 

The main blood supply is via the ascending pharyngeal artery from the external carotid artery (ECA) and branches from the petrous portion of the internal carotid artery (ICA). Larger glomus jugulare tumors may also have blood supply from other branches of the ECA, ICA, vertebral artery, and thyrocervical trunk.

The walls of the jugular foramen are formed anterolaterally by the petrous bone and posteromedially by the occipital bone. The canal follows an anterior, inferior, and lateral direction to exit the skull.

The posterolateral portion of the foramen (pars venosa) contains the jugular bulb, posterior meningeal artery, and cranial nerves X and XI. The anteromedial portion (pars nervosa) contains the inferior petrosal sinus and cranial nerve IX. The jugular bulb is situated between the sigmoid sinus and the internal jugular vein. The lower cranial nerves are situated medial to the medial wall of the jugular bulb. The inferior petrosal sinus enters the medial aspect of the jugular bulb via several channels anterior to cranial nerves IX, X, and XI.

Many important structures are in proximity to the jugular bulb, including the internal auditory canal, the posterior semicircular canal, the middle ear, the medial external auditory canal, the facial nerve (posterolaterally), and the ICA (anteriorly) within the carotid canal. At the extracranial end of the jugular foramen, the ICA, internal jugular vein, and cranial nerves VII, X, XI, and XII are within a 2-cm area.

Contraindications

 Because this tumor is rare and may present with various symptoms, surgery may be contraindicated for various reasons, including age and general physical condition. Surgical resection of the glomus tumor is relatively simple and complication free for type I tumors. Large tumors that affect the lower cranial nerves and extend beyond the petrous apex carry a significant risk of postoperative complications, especially in older patients. In these cases, other modalities of treatment should be considered (eg, embolization, radiation, gamma knife radiosurgery, intratumoral injection of cyanoacrylate glue).

Glomus Tumors Workup

Staging

The Glasscock-Jackson and Fisch classifications of glomus tumors are widely used. The Fisch classification of glomus tumors is based on extension of the tumor to surrounding anatomic structures and is closely related to mortality and morbidity.

• Type A tumor - Tumor limited to the middle ear cleft (glomus tympanicum)
• Type B tumor - Tumor limited to the tympanomastoid area with no infralabyrinthine compartment involvement
• Type C tumor - Tumor involving the infralabyrinthine compartment of the temporal bone and extending into the petrous apex
• Type C1 tumor - Tumor with limited involvement of the vertical portion of the carotid canal
• Type C2 tumor - Tumor invading the vertical portion of the carotid canal
• Type C3 tumor - Tumor invasion of the horizontal portion of the carotid canal
• Type D1 tumor - Tumor with an intracranial extension less than 2 cm in diameter
• Type D2 tumor - Tumor with an intracranial extension greater than 2 cm in diameter
   
   

  Glomus Tumors Treatment & Management

  Medical Therapy

  Some cases require no treatment. Often, glomus jugulare tumors are diagnosed within the sixth or seventh decade of life and can be followed by imaging only and may not need surgical intervention.
  
  A study from Vanderbilt University found that in the absence of brainstem compression or concern for malignancy, observation of  glomus jugulare tumors can be a viable initial management approach for elderly patients. Of 15 patients studied (80% female; median age, 69.6 yr), radiologic growth occurred in 5 patients. The median growth rate of the 5 enlarging tumors was 0.8 mm/yr (range, 0.6-1.6 mm/yr) using maximum linear dimension, or 0.4 cm³/yr (0.1-0.9 cm³/yr) with volumetric analysis. No deaths were attributable to tumor progression or treatment. 
  
  Medical therapy may be indicated in some cases. Alpha-blockers and beta-blockers are useful for tumors secreting catecholamines. They are usually administered for 2-3 weeks before embolization and/or surgery to avoid potentially lethal blood pressure lability and arrhythmias. Successful treatment of pulmonary metastases with etoposide (VP-16) and cisplatin has been described. In a preliminary report, a somatostatin analogue (octreotide) has been successfully used for growth control of somatostatin receptor–positive tumors.
  

  Surgical Therapy

  Surgery is the treatment of choice for glomus jugulare tumors. However, more recently, radiation therapy, particularly a gamma knife radiosurgery, has been shown to provide good tumor growth control with a low risk of treatment-related cranial nerve injury.
  
  
  A large retrospective, multicenter, international study analyzed the long-term outcome in 132 patients with primary radiation treatment or radiation after partial resection of a glomus tumor. The study found long-term successful control of the tumor growth, improvement of tinnitus and overall neurological status, as well as cranial nerve function. These results strongly suggest that gamma knife radiosurgery is becoming the treatment of choice for glomus tumors. 
  
  A German study of 32 patients who underwent stereotactic radiosurgery for glomus jugulare tumors showed that stereotactic linear accelerator (LINAC) radiosurgery achieved excellent long-term tumor control, along with a low rate of morbidity. According to the study, following LINAC stereotactic radiosurgery, 10 of 27 patients showed a significant improvement of their previous neurologic complaints, whereas 12 patients remained unchanged. No tumor progression was observed. Five patients died due to unrelated causes. Overall survival rates after 5, 10, and 20 years were 100%, 95.2% and 79.4%, respectively.
  
  
  Because resection of glomus jugulare tumors can be challenging due to their inherent vascularity, preoperative embolization of these tumors with ethylene vinyl alcohol (Onyx) has been proposed.A study by Gaynor et al showed a dramatic reduction of blood loss and facilitation of surgical resection, but these results came at the price of a higher incidence of cranial nerve neuropathy.
  
  
  The surgical approach depends on the localization and extension of the tumor. Intraoperative monitoring including EEGs and somatosensory-evoked potentials (SSEPs) are routinely used.
  Fisch type A tumors (see Pathophysiology) can be excised by a transmeatal or perimeatal approach.
  
  Type B tumors (see Pathophysiology) require an extended posterior tympanotomy.
  Type C tumors (see Pathophysiology) require radical resection via a standard combined transmastoid-infratemporal or transtemporal-infratemporal approach with or without internal carotid artery (ICA) trapping, preceded by external carotid artery (ECA) embolization or superselective embolization. Intraoperatively, temporarily occlude the transverse or sigmoid sinus with EEG monitoring to determine whether vein bypass should be performed for total resection. Surgery leads to therapeutic success in about 90% of patients. Intratumoral injection of cyanoacrylate glue has been proposed to control bleeding.
  
  Large type D tumors (see Pathophysiology) need to be treated with a combined otologic and neurosurgical approach. An infratemporal approach with a skull base resection and a posterior fossa exploration are the most advisable in attempting to remove the entire tumor. Partial resection of the tumor needs to be followed by radiation and follow-up MRI/CT scanning.
  
  Radiation therapy and radiosurgery may be indicated. Both classic fractionated radiation therapy (40-50 Gy) and stereotactic radiosurgery (eg, gamma knife surgery) are successful in long-term control of tumor growth and in decrease of catecholamine excretion in functional tumors; however, the short duration of observation after stereotactic radiosurgery does not allow for definite conclusions. Radiation treatment is advised as the sole treatment modality for elderly or infirm patients who are symptomatic, especially those with extensive or growing tumors.
  
  Gross total resection of some extensive tumors may be extremely difficult and may carry unwarranted risk. In such cases, radiotherapy may be indicated to treat residual tumor following subtotal resection.However, a 2004 study by Prahbu showed that even complex glomus tumors can be managed surgically. See the images below.
  
  

  

  A significant decrease of tumor vascular blush (arrows) following embolization of a norepinephrine-secreting glomus jugulare tumor with intracranial and cervical extension.

  
  

  

  CT imaging demonstrates the extent of bony destruction (white and black arrows) by the tumor. The normal jugular foramen on the left (arrow head) is shown for comparison. The patient subsequently underwent surgical resection of the extracranial portion of this extensive tumor. The remaining intracranial portion was treated with radiation therapy (54 Gy). Follow-up evaluations, including imaging and laboratory investigations, demonstrated long-term control of both tumor growth and catecholamine production.

  
  

  Preoperative Details

  If routine screening for catecholamine is positive (3 times the reference range), alpha-blockers and beta-blockers are administered for 2-3 weeks before surgery and embolization. This helps to avoid blood pressure lability and arrhythmias. In emergent cases, 3 days of treatment is adequate.
  

  Intraoperative Details

  Surgical approach depends on the localization and extent of the tumor (see Pathophysiology). Fisch type A tumors can be excised by a transmeatal or perimeatal approach. Type B tumors require an extended posterior tympanotomy. Type C tumors require radical resection via a standard combined transmastoid-infratemporal or transtemporal-infratemporal approach with or without ICA trapping, preceded by external carotid artery embolization or superselective embolization. Surgery leads to therapeutic success in about 90% of patients. Treat large type D tumors with a combined otologic and neurosurgical approach. An infratemporal approach with a skull base resection and a posterior fossa exploration are advisable in the attempt to remove the entire tumor.
  

  Postoperative Details

  Patients are usually in the sixth decade of life; therefore, careful monitoring of cardiac function is advisable, especially if a catecholamine secreting tumor was only partially resected.
  Postoperative lower cranial nerve deficits need to be carefully diagnosed, and, when present, early rehabilitation is advocated.
  

  Follow-up

  Radiologic and, when indicated, endocrinologic monitoring for tumor growth or regrowth is indicated every 6 months to 1 year for 2 years and then, depending on the dynamics of the tumor behavior, every 2 years. See the images below.
  

  

  Lateral carotid arteriogram obtained 22 years after radiation therapy in a 20-year-old woman who presented in June 1970 with episodic hypertension, headaches, and palpitations.

  
  

  

  Corresponding MRI of the tumor depicted in the previous image indicating no evidence of tumor growth over time.

  
  

  Complications

  Complications of surgery include death, cranial nerve palsies, bleeding, cerebrospinal fluid (CSF) leak, meningitis, uncontrollable hypotension/hypertension, and tumor regrowth.
  Complications of radiation include ICA thrombosis, secondary tumor development, pituitary-hypothalamic insufficiency, CSF leak, tumor growth, and radiation necrosis of bone, brain, or dura.
  

  Outcome and Prognosis

  Glomus jugulare tumors may grow slowly and produce cranial nerve palsies that, to a certain point, are benign and mostly cosmetic. However, despite this optimistic assessment, a recent study showed a long-term reduced quality of life in patients with glomus tumors.
  
  The mortality rate is 6.2% among patients treated with radiation and 2.5% among those treated surgically. The overall mortality rate is 8.7%.
  Twenty years after treatment, the survival rate is 94%, and 77% of patients remain symptom free. In 1945, Rosenwasser described the first patient diagnosed with glomus jugulare tumor. The patient survived until 1987.
  

  Future and Controversies

  Surgery is the treatment of choice for glomus tumors, and its effectiveness will improve with intraoperative guiding and imaging systems.
  
  The cooperative work of neurosurgeons and neuro-otologists to surgically resect Fisch type A, B, and C tumors has proven to be of value. However, definitive optimal treatment of type D glomus jugulare tumor is still controversial.
  
  Because of its long-term effects on the bone and brain, radiation that is not stereotactically targeted is outdated. Radiosurgery with its influence on neuro-oncology must be proven useful in treatment of these slowly growing tumors. 
  
  Continued tumor growth and postsurgical damage to the lower cranial nerves are issues that still need to be successfully addressed.
  Recent genetic research on familial glomus jugulare tumors suggests future directions of treatment towards gene manipulation.