Posttraumatic syringomyelia: predisposing factors.

Posttraumatic spinal cord cavitation (syrinx) and progressive myelopathy associated with a posttraumatic syrinx (PTS) have been recognized for many years. Predisposing factors for PTS have not been well defined. All symptomatic PTS patients (n = 58) treated at the University of Toronto neurosurgical units over 30 years were analysed retrospectively to discover risk factors for the development of PTS. There were 46 males and 12 females (mean age 42.2 years); 28 patients had cervical (CSCI), and 30 had thoracic and lumbar spinal cord injuries (TSCI). Neurological deficit was complete in 40 (69%) compared with 43% complete injuries in the concurrent spinal and injury (SCI) population in general (p = 0.0003). Onset of PTS was earlier with: increasing age (p < 0.02), cervical and thoracic levels of injury (p < 0.007 and p < 0.02, respectively, compared with lumbar injuries), dislocated fractures (p < 0.003) and spinal surgery (p < 0.001) and, marginally, with complete SCI (p = 0.06). Mean time to onset of PTS appears to have decreased in recent years (p < 0.0001). PTS follows complete spinal cord injury (SCI) more often than incomplete and is frequently associated with arachnoiditis. Onset is earlier with increasing age, cervical and thoracic levels compared with lumbar, displaced fractures and spinal instrumentation without decompression. A group of SCI patients who are at greater risk of developing early PTS is thus identified, facilitating cost-effective follow-up.

Cerebrospinal fluid leak after acoustic neuroma surgery: influence of tumor size and surgical approach on incidence and response to treatment.

OBJECT: The aims of this study were to review the incidence of cerebrospinal fluid (CSF) leakage complicating the removal of acoustic neuroma and to identify factors that influence its occurrence and treatment. METHODS: Prospective information on consecutive patients who underwent operation for acoustic neuroma was supplemented by a retrospective review of the medical records in which patients with CSF leaks complicating tumor removal were identified. This paper represents a continuation of a previously published series and thus compiles the authors' continuous experience over the last 24 years of practice. In 624 cases of acoustic neuroma the authors observed an overall incidence of 10.7% for CSF leak. The rate of leakage was significantly lower in the last 9 years compared with the first 15, most likely because of the abandonment of the combined translabyrinthine (TL)-middle fossa exposure. There was no difference in the leakage rate between TL and retrosigmoid (RS) approaches, although there were differences in the site of the leak (wound leaks occurred more frequently after a TL and otorrhea after an RS approach, respectively). Tumor size (maximum extracanalicular diameter) had a significant effect on the leakage rate overall and for RS but not for TL procedures. The majority of leaks ceased with nonsurgical treatments (18% with expectant management and 49% with lumbar CSF drainage). However, TL leaks (especially rhinorrhea) required surgical repair significantly more often than RS leaks. This has not been reported previously. CONCLUSIONS: The rate of CSF leakage after TL and RS procedures has remained stable. Factors influencing its occurrence include tumor size but not surgical approach. The TL-related leaks had a significantly higher surgical repair rate than RS-related leaks, an additional factor to consider when choosing an approach. The problem of CSF leakage becomes increasingly important as nonsurgical treatments for acoustic neuroma are developed.

Primary spinal epidural mantle cell lymphoma: case report.

OBJECTIVE AND IMPORTANCE: Mantle cell lymphoma is a distinct clinicopathological type of non-Hodgkin's lymphoma that often presents at an advanced stage, with systemic spread. Spinal involvement is uncommon and generally occurs as part of advanced disease or generalized relapses. Primary spinal epidural lymphoma is a rare initial manifestation of non-Hodgkin's lymphoma, and mantle cell lymphoma with initial presentation in the spinal epidural space is extremely rare, having been previously reported in only two cases. CLINICAL PRESENTATION: We report a case of a 71-year-old man who presented with increasing weakness and numbness of the legs. Magnetic resonance imaging revealed a spinal epidural mass in the lumbosacral region. INTERVENTION: The patient underwent a partial L4 and L5-S1 laminectomy, with incomplete resection of the mass for spinal decompression and tissue diagnosis. Mantle cell lymphoma was diagnosed in the pathological examination. CONCLUSION: After radiotherapy, the disease recurred with a soft-tissue mass in the anterior maxillary area of the face. The patient underwent restaging and was treated with chemotherapy, with only a partial response. Mantle cell lymphoma with primary spinal epidural presentation is rare. This diagnosis can be established and other causes of spinal cord compression can be ruled out by obtaining tissue for proper histopathological examinations. Because of its aggressive behavior and poor prognosis, mantle cell lymphoma should be treated using a combined-modality approach.

A study of vestibular schwannomas using positron emission tomography and monoclonal antibody Ki-67.

OBJECTIVE: This study aimed to evaluate the role of positron emission tomography (PET) as an in vivo determinant of tumor aggressiveness and growth. STUDY DESIGN: The study design was a prospective pilot study. SETTING: Positron emission tomography was performed at the Clarke Institute of Psychiatry. All patients were treated at the Sunnybrook Health Science Centre. Both institutions are affiliated with the University of Toronto, Toronto, Canada. PATIENTS: The study consisted of five consecutive patients with vestibular schwannomas with tumor size of 1 cm or larger within the cerebellopontine angle. One was a recurrent tumor and four were primary tumors. INTERVENTIONS: Preoperative PET studies were conducted using 18-fluorodeoxyglucose (FDG) as a radionuclide tracer to measure glucose metabolism within tumors. Tumors were processed and immunostained against Ki-67 nuclear antigen; their proliferative potentials were quantified based on immunoreactivity of tumor cells. MAIN OUTCOME MEASURES: Tumor metabolic activity on PET was compared with that of contralateral cerebellum to arrive at an FDG index. This number was compared with clinical parameters and Ki-67 reactivity. RESULTS: On PET, all tumors showed less metabolic activity than the cerebellum. The FDG uptake varied greatly between tumors independent of clinical parameters. All the tumors had a low proliferative index (<5%) with immunohistochemistry; there were quite a bit of intralesional variations in proliferative activities. CONCLUSION: Large tumor size and recurrent disease did not correlate well with increased FDG uptake on PET. Similarly, they did not show increased cellular activities as expressed by Ki-67 immunostaining.

Changing practice and costs of carotid endarterectomy in Toronto, Canada.

BACKGROUND AND PURPOSE: During our annual audits of carotid endarterectomy (CEA) in Toronto metropolitan hospitals, we have been aware of major changes in the practice of this operation in recent years. To evaluate the effect of changing practice on costs of carotid endarterectomy, we have therefore compared the effects of changes in length of stay, complication rates, and other variables on cost during the last 3 years for which we have complete data. METHODS: We evaluated 757 consecutive patients, of whom 600 had CEA procedures in 3 teaching hospitals, and 190 procedures in 2 community hospitals in metropolitan Toronto. We estimated costs using a specially designed computer program, Transitional System Incorporated, including surgical complications, in patients admitted between January 1994 and December 1996. RESULTS: There was a significant decrease in length of stay in both groups of hospitals, mainly due to preoperative outpatient evaluation but also due to lower complication rates, which probably reflect an increase in asymptomatic surgery in both hospital groups. Costs fell from approximately $8000 per procedure to $5000 in asymptomatic patients and from approximately $10,000 to $7000 in symptomatic patients (Can $). CONCLUSIONS: Major changes in the management of patients undergoing CEA have resulted in a significant decrease in both length of hospital stay and utilization of postoperative intensive care. At the same time, complication rates have significantly fallen, although our mortality and morbidity figures remain slightly higher than those from published multicenter trials. Future changes in surgical practice in Canada, including noninvasive carotid imaging, should produce even lower costs within the next few years.

Cervical myelopathy caused by hypoplasia of the atlas: two case reports and review of the literature.

OBJECTIVE AND IMPORTANCE: Congenital anomalies of the posterior arch of the atlas (C1) are uncommon. They range from partial clefts to total agenesis of the posterior arch. Developmental cervical canal stenosis is a congenital anomaly that may cause cervical myelopathy. Myelopathy caused by cervical stenosis at the level of the atlas has been reported in only three cases. We present two cases of nontraumatic cervical myelopathy caused by spinal stenosis at the level of the atlas associated with a hypoplastic but complete posterior arch of C1. CLINICAL PRESENTATION: Two elderly Chinese men developed cervical myelopathy gradually during months to years, without preceding trauma. Imaging revealed a hypoplastic but complete posterior C1 arch associated with changes of spondylosis in both patients, producing severe spinal stenosis and spinal cord compression. Posterior decompression was achieved in both by the removal of the posterior arch of C1 with its surrounding thickened posterior ligaments. Symptoms and clinical findings improved in the two patients during the follow-up period. CONCLUSION: The anomaly presented in our two cases differs from the established classification of congenital abnormalities of the posterior arch of the atlas, suggesting a different embryological defect. The hypoplastic posterior C1 arch created a congenitally narrowed spinal canal in our patients, rendering the spinal cord more susceptible to compression related to degenerative changes of the spine. Surgical removal of the shortened posterior C1 arch and surrounding degenerative ligaments is an effective treatment for symptomatic patients with this condition.

Recurrent intracranial hemorrhage due to postpartum cerebral angiopathy: implications for management.

BACKGROUND: Postpartum cerebral angiopathy as a cause of hemorrhagic stroke in young women is not well recognized. It is unknown whether this disorder represents a true inflammatory vasculitis or transient vasoconstriction related to the hormonal events of pregnancy and the postpartum period. CASE DESCRIPTION: A 39-year-old woman presented with postpartum intracranial hemorrhage and, 32 months later, with subarachnoid hemorrhage, following normal pregnancies. Cerebral angiography obtained after each stroke demonstrated diffuse irregularity of branches of the middle cerebral arteries consistent with a diffuse vasospastic process or classic vasculitis. Neurological deficits resolved and results of a transcranial Doppler study normalized after a short course of high-dose corticosteroids following the second stroke. CONCLUSIONS: Postpartum cerebral angiopathy should be considered in the differential diagnosis of recurrent intracranial hemorrhagic stroke in young women. Recognition of this condition may preclude treatment with potentially toxic therapies for vasculitis and will have important implications for counseling women on subsequent pregnancies.

Severe tension pneumocephalus complicating frontal sinus osteoma.

BACKGROUND: Tension pneumocephalus, the accumulation of intracranial gas under pressure, is a rare but potentially life-threatening condition which can complicate craniofacial surgery, trauma, or cranial tumor. It presents as an acute or subacute expanding mass lesion. CASE REPORT: We present a case of a 40-year-old male who developed tension pneumocephalus as a consequence of a previously detected but untreated frontal sinus osteoma. Despite prompt decompression and repair of the fistulous connection between the sinus and the intracranial compartment, the patient suffered permanent frontal lobe damage with significant neurocognitive sequelae and seizures. CONCLUSIONS: This case illustrates that tension pneumocephalus can be a dangerous entity with potential for early mortality and long-term morbidity. We recommend, therefore, early treatment and close follow up of destructive lesions involving the posterior frontal sinus wall.

Primary intramedullary primitive neuroectodermal tumor of the spinal cord: case report and review of the literature.

OBJECTIVE AND IMPORTANCE: Primary intraspinal primitive neuroectodermal tumors (PNETs) are rare. We report a case and review the literature. CLINICAL PRESENTATION: A 22-year-old woman presented with rapidly progressive paraparesis and neurogenic bladder. INTERVENTION: Preoperative computed tomography myelograms revealed a complete block at T12-L1, consistent with an intramedullary lesion. An urgent operation was performed with gross total tumor removal. The pathological findings were consistent with a PNET. Recurrence was noted within 10 weeks of surgery and has been somewhat responsive to chemotherapy and radiotherapy thus far. A review of the English literature shows that only 13 cases of primary intraspinal PNETs have been reported to date, and the present case is the second one in which the tumor was purely intramedullary. Most of the reported patients survived less than 2 years. CONCLUSION: Primary intraspinal PNETs are rare tumors and carry a poor prognosis.

Somatosensory evoked potential identification of sensorimotor cortex in removal of intracranial neoplasms.

OBJECTIVE: To assess the ease and reliability of routine use of somatosensory evoked potentials (SSEPs) for identification of sensorimotor cortex in brain tumour removal and to document its influence on the performance and outcome of surgery. METHODS: SSEPs in response to contralateral median nerve stimulation were recorded from the cortical surface by means of a four lead electrode strip. Polarity reversal of short latency SSEP waves was used to identify the position of the central sulcus in 46 consecutive craniotomies for removal of metastases, gliomas, or meningiomas located in, near, or overlying sensorimotor cortex. RESULTS: SSEPs were successfully recorded in 43/46 cases (94%) with demonstration of polarity reversal in 42/43 (98%). SSEP localization led to modification of 14/42 (33%) procedures, most frequently because of either displacement or involvement of sensorimotor cortex by tumour. Six patients (14%) developed new neurological deficits but none of these was attributable to incorrect identification of sensorimotor cortex. CONCLUSIONS: SSEP polarity reversal is a simple, reliable, accurate, and inexpensive method of localizing sensorimotor cortex under general anaesthesia. Correct identification is possible when sensorimotor cortex is displaced or when surface anatomy is obscured by tumour. Routine use of this technique should be considered in all procedures for lesions located near the central sulcus.

Hearing preservation in the removal of intracanalicular acoustic neuromas via the retrosigmoid approach.

In a series of 514 consecutive operations for complete excision of acoustic neuromas, 94 procedures were performed via a retrosigmoid approach to preserve the patient's hearing. Twenty-six of these procedures (5.1%) were performed in cases of intracanalicular tumor and 68 (13.2%) were for larger lesions in which most of the tumor was located medial to the porus acusticus within the cerebellopontine angle. Preservation of useful hearing was achieved in 13 (50%) of 26 patients with intracanalicular tumors and in 20 (29%) of 68 with larger tumors. A trend toward higher success rates in intracanalicular tumors appears to be present, although the difference is not statistically significant (p = 0.09). Normal or near normal facial function (House and Brackmann Grades I and II) was present postoperatively in 25 (96%) of 26 patients. Indications for treatment of intracanalicular acoustic neuromas are considered and treatment alternatives are reviewed. Results from other series reporting removal of intracanalicular acoustic neuromas are considered with respect to hearing conservation and postoperative facial nerve function. Surgical excision of intracanalicular acoustic neuromas in otherwise healthy patients appears to be warranted if preservation of useful binaural hearing is considered a worthwhile objective and if perioperative morbidity can be maintained at an acceptably low level. The retrosigmoid approach is familiar to all neurosurgeons and offers a comparable success rate for hearing conservation and probably a superior outcome in terms of facial nerve function when compared with the middle fossa approach.

Cavernous malformation presenting as an extra-axial cerebellopontine angle mass: case report.

OBJECTIVE AND IMPORTANCE: We describe a rare case of an extra-axial cavernoma of the cerebellopontine angle without internal auditory canal involvement and with an unusual appearance on preoperative magnetic resonance imaging (MRI). Only three cases of cerebellopontine angle cavernomas have been previously reported, and none of these reports included preoperative MRI. CLINICAL PRESENTATION: A young man presented with subacute left facial hypesthesia and chronic asymmetrical sensorineural hearing loss. MRI revealed a mass, which was isointense on T1- and T2-weighted images, with evidence of hemorrhage (methemoglobin and hemosiderin). The lesion did not enhance after the injection of gadolinium. INTERVENTION: The lesion was removed without difficulty by a suboccipital approach, with intraoperative electrophysiological monitoring of facial and cochlear nerves. Facial paresis cleared postoperatively. CONCLUSION: The present case suggests that the appearance of cerebelopontine angle cavernomas as revealed by MRI may be similar to that of intraparenchymal cavernomas. This is in contrast to previously reported cases of extra-axial cavernomas at other sites. Evidence of hemorrhage in an extra-axial lesion revealed by MRI suggests a possible diagnosis of cavernoma.

Prognostic factors in intraoperative facial nerve monitoring for acoustic neuroma.

OBJECTIVES: To determine the predictive value of intraoperative threshold stimulus for facial nerve outcome and the prevalence and prognostic value of persistent trains of activity and frequent spontaneous or mechanically induced contractions during acoustic neuroma surgery. STUDY DESIGN: Prospective recording and subsequent review of facial nerve activity. SETTING: Tertiary referral centre. PATIENTS AND METHODS: Consecutive patients undergoing acoustic neuroma surgery. Intraoperative facial nerve activity was digitised and stored on a personal computer for future analysis. Operative events were flagged. Recordings were available in 27 patients. MAIN OUTCOME MEASURES: Frequent mechanically induced contractions (< 20), prolonged trains of facial nerve activity (total time > 199 seconds), and facial nerve brainstem stimulus threshold were correlated with facial nerve outcome. RESULTS: A brainstem stimulus threshold > 0.1 mA was significantly associated with intermediate or poor facial nerve function (House-Brackmann grade > 2) on the sixth postoperative day, at 1 month and 6 months. Patients with normal or near-normal facial function on the first day and a threshold of > 0.1 mA were significantly more likely to develop a delayed facial nerve palsy. Frequent contractions were noted in 74% of patients and persistent train activity in 59%. Neither was predictive of facial nerve outcome. CONCLUSIONS: An elevated brainstem threshold is helpful in predicting delayed facial nerve palsy and suboptimal facial nerve outcome. Persistent train activity and frequent contractions, do not have major prognostic significance.

Hearing preservation in acoustic neuroma surgery: value of monitoring cochlear nerve action potentials.

This study reviews the hearing results in 80 consecutive patients who underwent complete removal of histologically proven acoustic neuromas by use of the suboccipital approach. Of these, 56 patients had successful monitoring of cochlear compound action potentials; 20 were not monitored because their surgery predated monitoring; and 4 had unsuccessful monitoring. A significant difference was found in hearing preservation rates between the group in whom compound action potential monitoring was performed and those in whom monitoring was either unavailable or failed (p = 0.02). Overall, 38% (30 of 80) had preserved hearing. There were 51 patients in whom the click threshold for the cochlear compound action potential was measured during surgery. Twenty-one patients had a threshold shift of 20 dB or less, 15 (71%) of these retained serviceable hearing (speech reception threshold < or = 50 dB; speech discrimination score > or = 60%). Of 12 patients in whom the threshold shift was 30 to 60 dB, none had serviceable hearing after surgery. The click threshold shift was predictive of a significant postoperative hearing change (p < 0.001).

Iatrogenic false aneurysm following repair of intracranial aneurysm.

False aneurysm of the intracranial arteries occurs infrequently as a complication of head injury and rarely as a consequence of other pathology. A case of false aneurysm of the supraclinoid internal carotid artery following minor intraoperative injury during clipping of a basilar-superior cerebellar aneurysm by the pterional approach is described. False aneurysm is a potential cause of recurrent intracranial hemorrhage after successful aneurysm clipping. Arterial bleeding which appears to come from the region of a branch origin should be viewed with concern even if it subsides spontaneously.

Postoperative pain following excision of acoustic neuroma by the suboccipital approach: observations on possible cause and potential amelioration.

Incisional pain and headache have been reported following cerebellopontine angle surgery via the suboccipital approach. The high incidence and severity of pain determined in a retrospective study of acoustic tumor patients prompted the present prospective study. Various modifications of the suboccipital approach have been employed in an attempt to isolate a possible cause and potential method of minimizing this problem. The results of this study suggest that pain may be caused, in part, by adherence of healing nuchal soft tissue to underlying dura following suboccipital craniectomy. The substitution of a craniotomy with bone flap replacement, which prevents such adhesion, appears to have significantly reduced the postoperative pain associated with the suboccipital approach.

Pain after surgery for acoustic neuroma.

Postoperative pain after surgery in the cerebellopontine angle (CPA) is acknowledged to occur, but is rarely taken into account as a factor in the analysis of morbidity of such surgery. It is widely acknowledged that some patients, having undergone such surgery, particularly by means of the suboccipital approach, report significant post-operative pain and headache. This study was undertaken to determine the incidence and severity of pain after excision of acoustic neuromas and to establish whether this differed between the suboccipital and translabyrinthine routes. Ninety-one percent of all patients (n = 58), who had the suboccipital approach used for removal of their tumor, were surveyed. A smaller group (n = 40), matched for tumor size, age, and sex, but in whom the translabyrinthine approach was used, was similarly studied. A standard questionnaire, designed to detect and quantify postoperative pain, was administered to each patient. Of patients who underwent tumor excision by means of the suboccipital approach, 63.7% experienced significant local discomfort and headache, whereas this was notably absent in all those who had undergone translabyrinthine excision. In view of the significant morbidity noted to follow the suboccipital approach, several modifications of the surgical technique used were devised.

Management of cervical spinal cord injury in ankylosing spondylitis: the intervertebral disc as a cause of cord compression.

Twenty-one patients with universal syndesmophytosis due to ankylosing spondylitis were identified in a consecutive series of 1578 patients with acute spine and spinal cord injuries. They were predominantly male, older than spinal cord-injured patients in general, and most were injured by falls. Approximately one-half were managed by halo-vest immobilization alone with good clinical and radiological outcomes. The remainder required surgery either for recurrent dislocation or for spinal cord compression associated with neurological deterioration. Extradural hematoma, a recognized cause of spinal cord compression in ankylosing spondylitis patients with spinal fractures, was encountered in two patients. Herniated intervertebral disc as a cause of spinal cord compression in ankylosing spondylitis does not appear to have been previously reported and was recognized three times in the present series, once in association with extradural hematoma. The pathology of ankylosing spondylitis is such that the nucleus pulposus tends to be spared, allowing disc herniation to occur in the heavily ossified spine. In virtually all patients, satisfactory correction of the flexion deformity could be safely accomplished following spinal fracture. It is concluded that fracture/dislocations of the cervical spine should be managed initially by halo-vest immobilization, without prior traction and with careful incremental correction of flexion deformity. Decompression is performed as required for extradural hematoma or intervertebral disc herniation, and internal fixation is carried out for recurrent dislocation.