Trimurti Nadkarni

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.

The importance of the cortical subarachnoid space in understanding hydrocephalus

OBJECT In this paper the authors define the role of the cortical subarachnoid space (CSAS) in poorly understood forms of hydrocephalus to cerebrospinal fluid (CSF) dynamics to improve understanding of the importance of the CSAS and its role in selecting patients for endoscopic third ventriculostomy (ETV). The secondary purpose of this work was to define testable hypotheses to explain enigmatic disorders of CSF dynamics and to suggest how these concepts could be tested. METHODS The magnitude of the contribution of the CSAS is explored using the solid geometry of concentric spheres. With this starting point, clinical conditions in which CSF dynamics are not easily understood are explored regarding the potential role of the CSAS. Overall, problems of CSF dynamics are easily understood. Insights may be gained when the results of a pathological process or its treatment vary from what has been expected. RESULTS Acute changes in ventricular volume at the time that hydrocephalus develops, the failure of shunts, and the changes in ventricular volume with shunt repair may occur very rapidly. Changes in the volume of water in the brain, especially in the brain substance itself, are unlikely to occur at this rapid rate and may be interpreted as a simple redistribution of the CSF between the ventricle and CSAS with no initial change in the actual volume of brain parenchyma. Problems such as pseudotumor cerebri, shunt failure with nonresponsive ventricles, and negative-pressure hydrocephalus can be explained by assessing the ability of ventricular CSF to flow to the CSAS and the ability of this fluid to exit this compartment. Ventricular enlargement at the time of shunt failure implies a failure of flow between the ventricles and CSAS, implying that all patients who show this phenomenon are potential candidates for ETV. CONCLUSIONS The important role of the CSAS in the pathophysiology of various forms of hydrocephalus has been largely ignored. Attention to the dynamics of the CSF in this compartment will improve understanding of enigmatic conditions of hydrocephalus and improve selection criteria for treatment paradigms such as ETV. These concepts lead to clearly defined problems that may be solved by the creation of a central database to address these issues.

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.

Basal Lateral Subtemporal Approach for Trigeminal Neurinomas: Report of an Experience with 18 Cases

Summary Subtemporal craniotomy centred on the external ear canal was used to surgically treat 18 trigeminal neurinomas. The approach was found to be suitable to deal with either or both the middle fossa and the posterior cranial fossa components of the tumour. The basal extension of the exposure was achieved by resection of the roots of the zygomatic arch, roof of the external ear canal and superior third of the mastoid bone. The temporalis muscle was rotated anteriorly. The direction of the approach to the tumour was the shortest and perpendicular from the surface and avoided any neural or vascular exposure or manipulation. The basal exposure was horizontally wide and significantly low which reduced the operating distance, limited the extent of temporal lobe retraction and provided additional space for manipulation of instruments. The exposure was manoeuvreable with anterior, posterior and medial expansion being possible during or prior to tumour resection. The approach had the advantage of being simple and relatively quick and of its familiarity to general neurosurgeons. The experience with the approach with trigeminal neurinomas and its possible advantages over other available approaches to these lesions are analysed in this report.

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.

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.

Supratentorial glioblastoma multiforme with spinal metastases

Glioblastoma multiforme is the most common malignant brain tumor in adults. Metastasis of intracranial glioblastoma via the cerebrospinal fluid to the spine is a rare occurrence. We present two cases of glioblastoma multiforme with spinal leptomeningeal spread who presented with back pain and paraparesis.

An intradural–extramedullary gas-forming spinal abscess in a patient with diabetes mellitus

Spinal infections are commonly reported to be located in the extradural or intramedullary spaces. Infection involving the intradural-extramedullary space are uncommon. We report a patient with uncontrolled diabetes mellitus and an infected foot ulcer who presented with a cervical cord abscess and intradural gas. Early diagnosis and aggressive treatment are necessary for a favourable outcome in gas-forming intradural spinal abscesses. To our knowledge, a gas-forming intradural spinal abscess has not been reported previously and we discuss the relevant literature.

Treatment of refractory intracranial hypertension in a spina bifida patient by a concurrent ventricular and cisterna magna-to-peritoneal shunt

Case reportA 20-year-old female born with a thoracic level myelomeningocele, Chiari II malformation, and hydrocephalus treated at birth developed clinical features of increased intracranial pressure (ICP) due to shunt malfunction. The patient became comatose. Her ICP remained high despite a functioning shunt and even after the ventricular catheter was exteriorized. Diagnostic imaging consistently demonstrated slit-like ventricles, a Chiari II malformation, and a tethered spinal cord. We attributed her neurological condition either to brainstem compression or increased ICP related to venous outlet obstruction at the foramen magnum.Outcome The patient improved rapidly after undergoing a Chiari II decompression and placement of a shunt from the cisterna magna and upper cervical subarachnoid space to the peritoneum connected by a “Y” connector to the ventricular catheter.Conclusion The complex hydrocephalus was effectively treated by this concurrent ventricular and cisterna magna-to-peritoneum shunt.

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.