Ketan Desai

Atlantoaxial fixation using plate and screw method: a report of 160 treated patients.

OBJECTIVE We review our experience with the use of the plate and screw method of fixation in the treatment of 160 patients with atlantoaxial instability during a 14-year period at our center. We previously described this method of fixation in 1994. METHODS Between 1988 and 2001, 160 patients with atlantoaxial instability were treated with the use of a plate and screw method of fixation at the Department of Neurosurgery at King Edward Memorial Hospital in Bombay, India. The study group was composed of 91 males and 69 females (mean age, 23 yr; age range, 18 mo-79 yr). Atlantoaxial instability was a result of congenital abnormality in 132 patients (83%) and occurred after trauma in 28 patients (17%). All patients had mobile, completely reducible atlantoaxial dislocation. For 3 months postoperatively, a hard cervical collar was used. The mean follow-up period was 42 months (range, 4 mo-14 yr). RESULTS Three patients died in the postoperative phase. Successful stabilization of the atlantoaxial region was documented with dynamic radiography in the other 157 patients. There was no incidence of implant rejection. In one patient, one screw was found to be broken 18 months after surgery; however, firm bony fusion was documented in this patient. There were no neurological, vascular, or infective complications. CONCLUSION The plate and screw method of fixation with the use of intra-articular bone grafts in patients with atlantoaxial instability yielded a 100% fusion rate with a low incidence of complications.

Surgical management of colloid cyst of the third ventricle—a study of 105 cases

BACKGROUND Colloid cyst of the third ventricle is a relatively rare intracranial tumor. It generates tremendous interest for the neurosurgeon because of its benign nature, deep location, and an excellent prognosis when diagnosed early and excised. METHOD A retrospective analysis of 105 cases of third ventricle colloid cyst treated between 1967 to 1998 was conducted. The clinical presentation, radiological findings, different surgical approaches, and outcome were analyzed. The transcallosal and transcortical-transventricular approaches were predominantly used. Memory and psychological assessment were carried out both pre- and postoperatively. A computerized tomography (CT) scan was performed during follow-up. RESULTS The male to female ratio was 1.5:1. The age of the patients ranged from 10 to 68 years. Headache was the most common symptom. Papilledema and short-term memory disturbances were the most common signs. In 5 patients the colloid cyst was detected incidentally. Surgery for colloid cyst was performed in 93 patients. Transcallosal and transcortical-transventricular approaches were performed in 62 and 30 patients, respectively. In 1 patient the cyst was excised through the subfrontal lamina terminalis approach. Total excision was achieved in 90 patients, while partial cyst excision was done in three patients. Moderate to severe lateral ventricular enlargement was found in 76 patients at presentation. A ventriculoperitoneal shunt was the only surgical procedure performed in 7 patients. In 16 patients colloid cyst excision was conducted after cerebrospinal fluid (CSF) diversion via a shunt. No surgical treatment of any kind was performed in 5 patients. Five patients died. Eighty-six patients came for follow-up, with a range from 1 month to 25 years (average 3 years and 8 months). Postoperatively, transient recent memory deficits occurred in 14 patients, while a permanent recent memory loss was noted in 2 patients. There was no incidence of postoperative disconnection syndrome or behavioral disturbance. A CT scan was performed in 44 patients during follow-up. Recurrence was detected in 1 patient in whom the cyst had been partially excised. CONCLUSIONS Colloid cyst, although a benign tumor, is surgically challenging because of its deep midline location. Early detection and total excision of the colloid cyst carries an excellent prognosis.

Surgery on anterior foramen magnum meningiomas using a conventional posterior suboccipital approach: a report on an experience with 17 cases.

OBJECTIVEThe advantages of a posterior “conventional” suboccipital approach with a midline incision over lateral, anterolateral, and anterior approaches to anteriorly placed foramen magnum meningiomas are discussed. METHODSFrom 1991 to March 2000, 17 patients with foramen magnum meningiomas arising from the anterior or anterolateral rim of the foramen magnum underwent operations in the Department of Neurosurgery at King Edward Memorial Hospital and Seth G.S. Medical College. All patients were operated on in a semi-sitting position by use of a conventional suboccipital approach with a midline incision and extension of the craniectomy laterally toward the side of the tumor up to the occipital condyle. RESULTSThe patients ranged in age from 17 to 72 years, and the tumors ranged in size from 2.1 to 3.8 cm. The intradural vertebral artery was at least partially encased on one side in eight patients and on both sides in two patients. The brainstem was displaced predominantly posteriorly in each patient. A partial condylar resection was performed in two cases to enhance the exposure. Total tumor resection was achieved in 14 patients, and a subtotal resection of the tumor was performed in the other 3 patients. In one patient, a small part of the tumor was missed inadvertently, and in the other two patients, part of the tumor in relation to the vertebral artery and posterior inferior cerebellar artery was deliberately left behind. After surgery, one patient developed exaggerated lower cranial nerve weakness. There was no significant postoperative complication in the remainder of the patients, and their conditions improved after surgery. The average length of follow-up is 43 months, and there has been no recurrence of the tumor or growth of the residual tumor. CONCLUSIONFrom our experience, we conclude that a large majority of anterior foramen magnum meningiomas can be excised with a lateral suboccipital approach and meticulous microsurgical techniques.

Prognostic factors for cerebellar astrocytomas in children: a study of 102 cases.

Objective: To evaluate the prognostic factors influencing the length of survival of pediatric patients with cerebellar astrocytomas. Methods: The clinical data of 102 patients under the age of 12 years with cerebellar astrocytomas were retrospectively analyzed. The radiological features, surgical findings, histology and adjuvant radiotherapy were reviewed. Patients were followed up on an outpatient basis. Computerized tomography (CT) scans of the brain were performed to detect recurrence. Results: The age of the patients at presentation varied from 10 months to 12 years. The mean age at presentation was 7 years and 11 months. The average duration of symptoms was 5.8 months. The clinical features were predominantly related to intracranial hypertension and the location of the tumor. Twenty-six tumors were located in the vermis and 76 in the cerebellar hemisphere. The brain stem was involved in 20 patients. All 102 patients had a preoperative contrast-enhanced CT scan. Midline vermian tumors were predominantly solid and enhancing, whilst the hemispheric tumors were cystic and nonenhancing. The tumors were graded into three subgroups based on histological characteristics: pilocytic astrocytoma, low-grade fibrillary astrocytoma and high-grade fibrillary astrocytoma. Total, radical and subtotal excision, as determined by the surgical impression, were performed in 82, 16 and 4 patients, respectively. Postoperative radiotherapy was administered to 12 patients. CSF diversion was carried out in 11 of 79 cases who had moderate to severe hydrocephalus. Conclusions: Our study has shown that the location of the tumor (p < 0.05), histological grade (p < 0.001) and the extent of tumor resection (p < 0.001) have a significant and definitive relationship to the length of survival of pediatric patients with cerebellar astrocytomas. The patient’s age (p > 0.05) does not influence the outcome. We could not evaluate the effect of brain stem involvement and adjuvant radiotherapy in our study because of the small sample size.

Pathological laughter as a presenting symptom of massive trigeminal neuromas: report of four cases.

OBJECTIVE AND IMPORTANCE This is a report of four cases of huge trigeminal neuromas that presented with the principle symptom of pathological laughter (PL). CLINICAL PRESENTATION All four patients were male and were in either the third or fourth decade of life. In addition to PL, there were neurological deficits related to trigeminal nerve, brainstem, and cerebellar dysfunctions. INTERVENTION All tumors were radically excised via a lateral basal temporal approach. The PL was cured immediately after surgery. CONCLUSION PL sometimes precedes other neurological manifestations and may be a useful localizing sign. The clinical and radiological features in our cases suggest that PL is a result of extra-axial compression of the pons and adjoining neural structures.

Extradural arachnoid cysts: a study of seven cases.

Analysis of the management of 7 cases of extradural arachnoid cyst is presented. A brief review of the literature on the subject is presented. Seven cases of extradural arachnoid cysts were treated surgically between the years 1996 to 2002. These patients were analysed retrospectively. The average follow-up period was 32 months. Three patients were males and four were females and their ages ranged from 12 to 35 years. The patients presented with predominant complaint of progressive motor deficits. There were two cysts in the dorsal region, four in the dorsolumbar region and one in the cervicodorsal region. The extradural arachnoid cyst was located posterior to the dural tube and in the midline in six cases and all these cysts had bilateral multiple intervertebral foraminal extensions. In the case with a cervicodorsal cyst, the cyst was anterolateral to the dural tube and there was no foraminal extension. The surgery comprised of wide exposure of the cyst and radical marsupialization or resection of the cyst wall. There was no recurrence of the cyst during the period of follow-up. Radical resection of the walls leads to a lasting cure from extradural arachnoid cyst. The site of communication of the cyst contents with subarachnoid CSF could not be identified during the surgery in the series.

Retrospective analysis of peripheral nerve sheath tumors of the second cervical nerve root in 60 surgically treated patients.

OBJECT This study is a retrospective analysis of 60 surgically treated patients with 64 peripheral nerve sheath tumors (PNSTs) at the second cervical (C-2) nerve root. The anatomical subtleties of these tumors and their implications for surgical strategy when compared with other spinal PNSTs and other tumors in the foramen magnum region are reviewed. METHODS Sixty patients with C-2 PNSTs treated surgically in the Department of Neurosurgery at King Edward VII Memorial Hospital and Seth Gordhandas Sunderdas Medical College between 1992 and 2006 were studied. All patients underwent magnetic resonance imaging. Tumors were divided into 3 groups depending on their anatomical location identified during surgery. Those tumors located within or extending into the spinal dural tube were called Type A, those located within the dural tube of the C-2 ganglion were labeled as Type B, and tumors extending laterally into the paraspinal region were labeled as Type C. Follow-up durations ranged from 6 months to 15 years (mean 64 months). RESULTS There were 38 male and 22 female patients in the study, who ranged in age from 6 to 62 years (mean 28 years). Nine patients had clinical features indicative of neurofibromatosis (NF). The mean duration of symptoms at the time of presentation was 27 months (range 4 days-5 years). Two patients had no specific symptoms related to the C-2 PNST, 6 patients had only local symptoms such as neck pain or stiffness, and 52 patients had symptoms of varying degrees of myelopathy. There were 5 solely Type A tumors, 7 Type A + B tumors, 31 Type B tumors, and 21 Type B + C tumors. All Type A, A + B, and B tumors were totally resected. Seven of 21 Type B + C tumors were partially resected, and the remainder were completely resected. All patients postoperatively reported varying improvement in their preoperative symptoms. Except for patients with NF who were disabled by other tumors, the rest of the patients resumed their normal life style. There have been no cases of symptomatic tumor recurrence. CONCLUSIONS The majority of PNSTs located at the C-2 level in these patients probably arose from the large C-2 ganglion and are limited within the dural confines or are interdural in location. In contrast to other spinal PNSTs, the location of C-2 PNSTs is in most cases posterior to the lateral mass of the atlas and axis and the atlantoaxial joint and is exposed to the posterior without any bone cover. Radical tumor resection is safe, resolution of clinical symptoms is rapid, and recurrence rates are extremely low. In a selected number of cases, bone work for tumor exposure and resection can be entirely avoided.

Tuberculomas of the hypophysis cerebri: report of five cases

Tuberculomas involving the hypophysis cerebri are extremely rare lesions, and these may occur even in the absence of systemic tuberculosis. This report presents the clinical data of 5 patients harbouring tuberculomas of the pituitary gland. Sellar tuberculomas commonly mimic pituitary adenoma. Histological diagnosis of a sellar lesion is mandatory irrespective of the clinical presentation and radiological findings. A history of extracranial tuberculosis in the past associated with radiological findings like leptomeningeal enhancement, parenchymatous brain tuberculomas or a thickened pituitary stalk on contrast MRI, are indicative of the possibility of a sellar tuberculoma. The aim of surgery is tissue diagnosis and tumour debulking. The response to long-term antituberculous chemotherapy is excellent. There is often a complete resolution of the granuloma and a satisfactory recovery of visual and endocrinological function.

Developmental Deep Venous System Anomaly Associated with Congenital Malformation of the Brain

We report a rare case of developmental deep venous system anomaly. The great vein of Galen and the straight sinus were absent. Both internal cerebral veins and the basal veins of Rosenthal drained into a large frontal interhemispheric falcine vein, which eventually drained into the superior sagittal sinus. The patient also had an associated neuronal migration anomaly.

Basilar invagination and Chiari malformation associated with cerebellar atrophy: report of two treated cases

We report two patients with an unusual complex of anomalies wherein the basilar invagination and Chiari malformation was associated with marked cerebellar atrophy. Both patients presented with relatively severe lower cranial nerve deficits and showed clinical improvement following a posterior foramen magnum bony decompression. The pathogenesis of the anomalies is discussed and the rationale of treatment is analysed.