Browsing by Author "Vikas, V"

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    Acoustic neurinomas: Facial nerve preservation in large and giant tumors - a personal series of over 600 cases
    (13TH ASIAN-AUSTRALASIAN CONGRESS OF NEUROLOGICAL SURGEONS (AACNS), 2012) Nair, S; Gopalakrishnan, CV; Vikas, V; Sudhi Jr; Abraham, M; Menon, G; Easwer, HV; Krishnakumar; George, V; Amit, D
    The goal of vestibular schwannoma surgery has changed over years from preserving patient's life to total or near total excision with functional facial nerve preservation and with hearing preservation in selected cases. These tumours can be unilateral or bilateral, can be purely intracanalicular or intra-extracanalicular, can have varied sizes, can be purely solid or cystic with or without intratumoral bleed, can be vascular or avascular, can have extensive pial breaching with peritumoral edema, can be medially impacted into brainstem with extension across midline or laterally impacted into the petrous bone with involvement of cochlea, can be polylobular, can extend superiorly upto the ambient cistern or inferiorly below foramen magnum, may or may not have extratumoral arachnoid cap and may or may not be associated with hydrocephalus. Each of these poses different problems for the operating surgeon. Sometimes optimal bone removal may itself be complicated by large emissary veins or a highly placed jugular bulb. Over a thirteen and a half year period from 1st February 1998 to 14thNovember 2011, 610 cases of large and giant vestibular schwannomas were operatively managed with an operative mortality of <1% (6 cases). There were 63 patients (10.3%) of cystic vestibular schwannomas and 21 cases of bilateral vestibular schwannomas. Twelve patients of cystic schwannomas presented with imaging evidence of bleed. All the patients were operated by retrosigmoid route in the lateral position. A retrospective analysis of 100 consecutively operated cases was undertaken to compare the clinical presentation and surgical outcome for giant tumors (size >4.5 cm in any dimension on radiological imaging) as opposed to tumors of smaller sizes (large: 2.5 to 4.5 cm & small: <2.5 cm). While 25 patients in the study group had giant tumors, it was large in 72 and small in the remaining three. The incidence of preoperative hearing loss, trigeminal nerve involvement and cerebellar signs were almost identical in the giant and the large tumor groups. But the incidence of preoperative facial paresis, lower cranial nerve involvement and hydrocephalus was significantly more in the giant group. All the patients were operated by retrosigmoid approach in the lateral position. Excepting 5 patients (2 giant & 3 large), where only a sub / near total removal was done, all the remaining had total excision of the lesion. While anatomical preservation of seventh nerve could be achieved in 90% of the large tumors, it was only 60% in the giant category. Mean hospital stay was 18 and 15 days for giant and large group respectively. Acoustic neurinomas of all sizes can be operated by retromastoid approach alone with gratifying results. The technical issues of operative management with particular emphasis on extra-arachnoid dissection in preserving facial nerve is highlighted.
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    Colloid Cyst: Institutional Experience of 293 Cases
    (13TH ASIAN-AUSTRALASIAN CONGRESS OF NEUROLOGICAL SURGEONS (AACNS), 2012) Nair, S; Menon, G; Easwer, HV; Abraham, M; Vikas, V; Krishnakumar; Gopalakrishnan, CV; George, V; Sudhir, J
    Aim: To analyze the clinical presentation, surgical outcome of 293 cases of colloid cysts surgically managed over a period of 32 years beginning January 1980 to September 2011. Methods: Age range was between 9 to 66 years. Raised ICP headache was the most common initial presenting symptom in 74% followed by visual blurring in 7%, memory disturbance in 5.3%, intermittent headaches in 7.6%, drop attacks, gait unsteadiness in 3.4% and incidental in five patients (2%). Imaging with CT scan done showed the cyst to be hyperdense in 69%, isodense in 28% and hypodense in 4% of patients. Shorter duration of symptoms correlated with MRI T2W hyperintensity changes. While an interhemispheric transcallosal approach was used in 271, it was trans-cortical in 22 (endoscope assisted in 6 & endoscopically in 2). Results: Out of the 271 patients operated through the transcallosal approach, the cyst was removed through transforaminal route in 226, interforniceal rote in 24, subchoroidal in 14 and suprachoroidal in seven. Twenty-two patients underwent emergency surgery. Twenty-eight patients had CSF diversionary procedure (14 patients referred with preoperative shunt done elsewhere and 14 required postoperative CSF diversions). Complications included impaired memory in 35, hemiplegia/ hemiparesis in 8 and seizures in twelve. There was an operative mortality of 1% (3 cases). Eight patients had symptomatic recurrence of which 6 had total excision at first surgery. Conclusions: These potentially life threatening lesions can be removed safely through the interhemispheric transcallosal approach. Periodic follow-up with MR imaging is necessary as recurrence can occur even after apparent total excision.
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    Petroclival Meningiomas: Institutional Experience of 119 cases
    (13TH ASIAN-AUSTRALASIAN CONGRESS OF NEUROLOGICAL SURGEONS (AACNS), 2012) Nair, S; Gopalakrishnan, CV; Vikas, V; Abraham, M; Rao, RM; Menon, G; George, V; Easwer, HV; Sudhir, JK; Amit, D
    A retrospective analysis of 119 cases of petroclival-premeatal meningiomas surgically managed in their institute from 1st Jan 1990 till 14th November 2011 was carried out to see the outcome with various approaches. While the tumor resection was carried through an anterolateral/ lateral route in 32(27%), it was through a combined posterior subtemporal /pre or trans-sigmoid (posterior petrosal) in 24(20%) & retrosigmoid supra-paracerebellar route in 55 cases (46%). In three cases with extra cranial extension to infratemporal area, a modified Fisch approach was used. Five patients who were in poor clinical condition had only a CSF diversionary procedure. The percentage of these tumors operated by conventional retrosigmoid route has increased in the later part of the series thus proving that in many of these tumors without significant middle fossa extension, it is not necessary to use complex and time consuming skull base approaches which in themselves can cause morbidity. The tumor could be radically removed in 79 patients (66%), subtotally in 26 (22%) and decompression only in 9). Six patients had tumor excision in two stages. There was an operative mortality of 8.4% (10 cases). Out of the 85 patients on long term follow up 56 are independent. Six out of the eight patients who had symptomatic recurrence were re-operated.
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    Surgical Management of Foramen Magnum Meningiomas
    (NEUROSURGERY QUARTERLY, 2012) Nair, SN; Vikas, V; Gopalakrishnan, CV; Menon, G
    Background and Objective: Meningiomas involving the foramen magnum (FM) region are rare and constitute 1% to 7% of intracranial meningiomas. Surgical excision is difficult in view of the complex anatomy and the proximity to critical neurovascular structures. Our aim was to analyze the clinical presentation and surgical outcome of patients operated for FM meningiomas. Materials and Methods: Thirty patients who underwent surgery for FM meningioma over a period of 21 years were studied retrospectively. Case records and imaging studies were reviewed for demographic data, presenting symptoms, tumor location, surgical approach, and postoperative complications. The outcome was assessed on the basis of the Glasgow Outcome Scale (GOS). Results: Twenty-three women and 7 men ranging in age between 18 and 75 years were diagnosed after a mean symptom duration of 20 months. The choice of surgical technique was guided by the tumor location (anterior: 6, lateral: 19, posterior: 5), the position of the vertebral artery, and the extent of dural attachment. Although 11 of the lateral meningiomas were resected through the posterior approach, 8 were operated by the posterolateral route. Five anterior meningiomas were operated by the posterolateral corridor, whereas 1 was excised by a posterior approach reaching the tumor from either side of the cervico-medullary junction. Radical resection was performed in 28 patients; 2 patients with extradural extension underwent subtotal removal. There were 2 postoperative deaths, of whom 1 patient died after a surgery for recurrent tumor. Of the 27 patients who came for follow-up, 18 had a GOS of 5, 6 patients were moderately disabled (GOS 4), and 3 were severely disabled (GOS 2 and 3). One patient underwent revision surgery for symptomatic recurrence. Conclusions: Meticulous surgical planning is required for a safe and complete resection of FM meningiomas with minimal morbidity and mortality.
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    Techniques of Facial nerve preservation in vestibular schwannoma surgery
    (8TH ASIAN CONGRESS OF NEUROLOGICAL SURGEONS (ACNS 2010), 2010) Nair, S; Gopalakrishnan, CV; Vikas, V; Menon, G
    The goal of vestibular schwannoma surgery has changed over years from preserving patient's life to total or near total excision with functional facial nerve preservation and with hearing preservation in selected cases. These tumours can be unilateral or bilateral, can be purely intracanalicular or intra-extracanalicular, can have varied sizes, can be purely solid or cystic with or without intratumoral bleed, can be vascular or avascular, can have extensive pial breaching with peritumoral edema, can be medially impacted into brainstem with extension across midline or laterally impacted into the petrous bone with involvement of cochlea, can be polylobular, can extend superiorly upto the ambient cistern or inferiorly below foramen magnum, may or may not have extratumoral arachnoid cap and may or may not be associated with hydrocephalus. Each of these poses different problems for the operating surgeon. Sometimes optimal bone removal may itself be complicated by large emissary veins or a highly placed jugular bulb. Over a twelve and a half year period from 1st February 1998 to 1st November 2010, 547 cases of large and giant vestibular schwannomas were operatively managed with an operative mortality of <1% (5 cases). There were 59 patients (10.8%) of cystic vestibular schwannomas and 20 cases of bilateral vestibular schwannomas. Twelve patients of cystic schwannomas presented with imaging evidence of bleed. All the patients were operated by retrosigmoid route in the lateral position. A retrospective analysis of 100 consecutively operated cases was undertaken to compare the clinical presentation and surgical outcome for giant tumors (size >4.5 cm in any dimension on radiological imaging) as opposed to tumors of smaller sizes (large: 2.5 to 4.5 cm & small: <2.5 cm). While 25 patients in the study group had giant tumors, it was large in 72 and small in the remaining three. The incidence of preoperative hearing loss, trigeminal nerve involvement and cerebellar signs were almost identical in the giant and the large tumor groups. But the incidence of preoperative facial paresis, lower cranial nerve involvement and hydrocephalus was significantly more in the giant group. All the patients were operated by retrosigmoid approach in the lateral position. Excepting 5 patients (2 giant & 3 large), where only a sub / near total removal was done, all the remaining had total excision of the lesion. While anatomical preservation of seventh nerve could be achieved in 90% of the large tumors, it was only 60% in the giant category. Mean hospital stay was 18 and 15 days for giant and large group respectively. Acoustic neurinomas of all sizes can be operated by retromastoid approach alone with gratifying results. The technical issues of operative management with particular emphasis on extra-arachnoid dissection in preserving facial nerve is highlighted.