Biomedical subjects
Publications and source records attributed to J C Maroon.
Mucoceles arising from accessory paranasal sinuses about the orbit are quite rare. A case is reported of a retro-orbital mucocele arising from the pterygoid recess of the sphenoid sinus. The clinical and anatomical presentations, computerized tomographic and magnetic resonance imaging characteristics, and laser surgical management of such lesions are described.
There has long been a controversy over the cause of trigeminal neuralgia. Most clinical data favor a peripheral cause. However, most of the experimental data tend to favor a central mechanism. Drugs that are effective in the treatment of trigeminal neuralgia facilitate segmental inhibition in the trigeminal nucleus, as well as depressing excitatory transmission. The most plausible hypothesis to reconcile all of these observations is that trigeminal neuralgia has a peripheral cause and a central pathogenesis. Chronic irritation of the trigeminal nerve apparently leads to both a failure of segmental inhibition in the trigeminal nucleus, and ectopic action potentials in the trigeminal nerve. This combination of increased firing and impaired efficiency of inhibitory mechanisms leads to paroxysmal discharges in the trigeminal nucleus, which are perceived as attacks of trigeminal neuralgia when they involve nociceptive trigeminothalamic-relay neurons.
A retrospective clinical study of optic nerve sheath meningiomas based on 22 patients showed that symptoms most commonly develop in women between the ages of 35 and 60 years. The most common presenting symptoms were decreased vision and transient visual obscurations. In the earliest stages, many patients presented with normal to mildly impaired acuity (despite subjectively decreased vision), optic disc edema and enlargement of the blind spot. Optic disc edema was frequently associated with refractile bodies indicative of chronic swelling. Optic disc edema preceded the development of optic atrophy. Another group of patients presented with a history of longstanding vision loss, visual acuity of 20/200 or worse and optic atrophy. Optociliary shunt vessels were late findings only seen in five patients. The most consistent visual field abnormality was peripheral constriction. Cecocentral scotomas were uncommon. Intracranial involvement was present in five patients. There were two patients with bilateral optic nerve sheath meningiomas without CT evidence of intracranial involvement. Computerized tomography was found to be indispensable in the diagnosis of optic nerve sheath meningiomas and the detection of intracranial involvement.
We report the clinical features, radiological studies, operative management, and follow-up data in a series of 27 patients with tentorial meningiomas. Headache and extremity or gait ataxia were the most common presenting symptoms. Signs of elevated intracranial pressure and cranial nerve, pyramidal, or cerebellar deficits were the most common findings on neurological examination. Computed tomography was the single most important diagnostic tool. Cerebral arteriography was considered important to define arterial and venous relationships to the tumor. Two patients in the series underwent cerebrospinal fluid shunting only. The others underwent an operation on the tumor, with or without a shunt. There were 2 postoperative deaths early in the series, 1 due to cerebellar swelling and the other due to brain stem infarction. With an average follow-up of 5.5 years, 19 patients are independent and have resumed their premorbid level of activity. The pathological anatomy of these lesions is described. The different operative approaches to this tumor are discussed.
The authors review their experience with over 300 patients with orbital tumors, and summarize their surgical techniques and indications for each surgical approach. A fronto-orbital approach is described which is used for tumors with intracranial extension and for those located in the orbital apex and deep medial orbital compartment. Lateral micro- orbitotomy is used for tumors located in the superior, temporal, or inferior compartment of the orbit and those in the lateral apex. A medial microsurgical approach is used for tumors located medial to the optic nerve but not deep in the apex. By thus approaching tumors directly, optimal exposure is obtained and functional deficits are minimized. The pertinent surgical anatomy is illustrated and the technique of fine-needle aspiration biopsy is discussed.
Forty female patients with pituitary adenomas were studied retrospectively to determine whether factors could be identified that would help predict outcome from operation. Twenty-five patients had a normal prolactin level (less than or equal to 30 ng/ml) during the early postoperative period (less than or equal to 3 months) and 15 patients had persistent disease (prolactin greater than 30 ng/ml). Nine of the 25 patients who initially had normal prolactin levels during the early postoperative period were found to have elevated prolactin levels during the late postoperative period (greater than 3 months). As has been shown previously, tumor size and preoperative prolactin levels were important factors in predicting surgical outcome. Patients with smaller (Hardy Grades I and II) tumors had significantly better outcome than those with larger (Hardy Grades III and IV) tumors. Patients with successful surgical outcomes had significantly lower preoperative prolactin values (204 ng/ml) than those with operative failures (524 ng/ml). In addition to the known factors, the patient's age at the time of operation, the length of amenorrhea, and the patient's growth hormone response to insulin hypoglycemia were newly identified as factors that helped predict surgical outcome. Patients who were less than or equal to 26 years of age and who had had amenorrhea for less than or equal to 6 years at the time of operation had significantly better surgical outcomes. Patients with normal growth hormone responses to stimulation testing had significantly better surgical outcomes than those with a blunted preoperative growth hormone response. The data suggest that prolactin-secreting pituitary tumors may cause a progressive disorder for which operative cure may be obtained only early in the disease.
A procedure has been developed for maximizing decompression in patients with nonspecific orbital inflammatory disease or dysthyroid orbitopathy that involves removal of parts of all four orbital walls through a lateral orbitotomy using a 30-mm incision combined with a canthotomy and an inferior cul-de-sac incision. The procedure has been performed on seven orbits of four patients who had greater than 30 mm of forward placement of the eyes as measured by Hertel exophthalmometry and/or a 10-mm difference in the forward placement of the two eyes, indications considered for this procedure. The procedure has resulted in 10-17 mm of reduction in proptosis in these patients, which is consistently greater than that obtained by any other procedure. A complication of spinal fluid leak resulted in the recommendation that the procedure not be performed in patients over 65 whose dura is considered too thin to prevent spontaneous leakage and minimal surgical trauma. In all circumstances, this procedure must be performed by an experienced neuro-ophthalmic orbital surgical team.
The clinical and computed tomographic (CT) features of three consecutive cases of temporal lobe contusion emphasize the presentation and frequent subsequent progressive neurological deterioration. The initial presentation was one of lethargy and combativeness with little or no focal neurological deficits. Thereafter all patients developed progressive neurological deterioration with decreasing levels of consciousness and lateralizing signs. Computed tomography (CT) which aided in making the initial diagnosis was repeated following clinical deterioration. Worsening in the patient's clinical condition correlated positively with changes within the contusion as visualized by CT.
A surgical technique is described for radical decompression of the orbit for dysthyroid exophthalmopathy. The operation should be considered in a patient with proptosis greater than 30 mm bilaterally or one with unilateral proptosis of 10 mm or more greater than the opposite eye. Such exophthalmos is frequently associated wih corneal exposure and ulceration, extreme cosmetic disfigurement, and optic neuropathy. The surgical procedure is performed through a 35-mm lateral skin incision and a lateral canthotomy with subconjunctival dissection. All four walls of the orbit are partially removed. This panorbital decompression procedure has been performed on five patients, with reduction of preoperative proptosis by as much as 17 mm. Complications were minimal. A review of the effectiveness of other orbital decompressive procedures is presented. It appears that the four-wall decompressive procedure offers the maximum degree of orbital reduction.
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Patients with intracranial disorders are prone to develop hyponatremia with inability to prevent the loss of sodium in their urine. This was originally referred to as "cerebral salt wasting," but more recently is thought to be secondary to the syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Blood volume determinations were made in 12 unselected neurosurgical patients with intracranial disease who fulfilled the laboratory criteria for SIADH. Ten of the 12 patients had significant decreases in their red blood cell mass, plasma volume, and total blood volume. The finding of a decreased blood volume in patients who fulfill the laboratory criteria for SIADH is better explained by the original concepts of cerebral salt wasting than by SIADH. The primary defect may be the inability of the kidney to conserve sodium.
A patient with Klippel-Trenaunay-Weber (KTWS), pneumosinus dilatans, and familial Adie's syndrome who developed bilateral perioptic meningiomas is described. This case demonstrates the efficacy of fine-needle aspiration biopsy for tissue diagnosis of optic nerve tumors in blind eyes.
Adenomatous tissue was obtained from 10 women with evidence of prolactin-secreting pituitary adenoma at the time of transsphenoidal removal of the tumor. Tissue levels of prolactin (hPRL) were estimated after extraction and were compared to preoperative peripheral serum levels of hPRL. No correlation was found between the tissue and serum concentrations of hPRL, although high levels of hPRL were found in the tissue extracts. Electron microscopy confirmed active secretion of the individual cells, and the ultrastructural findings were compatible with prolactin-secreting adenomas. Associated with the active secretion was extensive exocytosis of the secretory granules away from the capillary wall. These findings suggest that, although active secretion of hPRL is occurring, large amounts of secreted hPRL are not available for immediate uptake into the capillary plexus; thus a slow absorption of hPRL could be taking place from the adenomatous tissue. These data could explain the failure of provocative tests of hPRL stimulation and inhibition to unequivocally characterize an adenoma in an individual with elevated serum levels of hPRL.
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In the last 5 years there has been a dramatic decrease in the deaths directly related to football participation. The incidence of serious spinal cord injuries, however, appears to be increasing. The number of quadriplegic athletes varies from an estimated 1 per 7,000 to 1 per 58,000 participants per year in different areas of the country. The majority of catastrophic head and neck injuries occurs while tackling or blocking, and defensive players are much more liable to sustain these injuries than offensive players. In addition to permanent and irreversible spinal cord damage, football players may suffer spinal concussions as well as spinal contusions. The latter may be manifested by severe burning paresthesias and dysesthesias in the extremities as the only symptoms. Furthermore, fracture-dislocations with ligamentous tears may be present in this syndrome, with no complaint of cervical pain. Adequate preconditioning and strengthening of the head and neck musculature prior to football participation are essential for the prevention of catastrophic head and neck injury. Furthermore, proper blocking and tackling techniques must be taught, and such punishing maneuvers as spearing, goring, and butt-blocking and tackling must be eliminated. Arbitrarily, most physicians discourage further football participation if an athlete has suffered three cerebral concussions. Strong consideration must be given, however, not only to the number and severity of the concussion, but also to any CAT scan evidence of cerebral edema, contusion, or hemorrhage. With this incredibly sensitive diagnostic tool, one concussion, which is associated with radiographic evidence of structural brain damage, may be enough to strongly discourage or forbid further football participation.
A patient had a thirteen-year history of symptoms clinically indistinguishable from classic migraine: a slowly progressive visual fortification spectrum lasting 40 minutes, followed by a five- to six-hour throbbing unilateral headache with nausea and vomiting. After unsuccessful migraine therapy, investigation revealed a large occipital lobe arteriovenous malformation (AVM). Surgical removal of the AVM resulted in immediate and total resolution of all symptoms.
Frontal sinusitis, or inflamatory complications of sinusitis, may occur as a consequence of frontal craniotomy when the sinus has been entered during the craniotomy. This may happen particularly during surgery to treat an aneurysm or to excise a tumor in the sellar area. These complications may also occur if the sinus is entered during routine craniotomy when the sinus is high or asymmetrical, or during reduction of frontal bone fractures. This presentation describes the etiology of such inflammatory complications and describes the approach to treatment of such complications, as well as outlining their prevention.
We think the use of the operating microscope in deep orbital surgery is essential for a safer and more accurate removal of the tumors that occupy this difficult surgical location.