Browsing by Author "Krishnakumar"

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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.