Browsing by Author "Easwer, HV"

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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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    Dexmedetomidine as an Anesthetic Adjuvant in Patients Undergoing Transsphenoidal Resection of Pituitary Tumor
    (JOURNAL OF NEUROSURGICAL ANESTHESIOLOGY, 2015) Gopalakrishna, KN; Dash, PK; Chatterjee, N; Easwer, HV; Ganesamoorthi, A
    Background: Transnasal transsphenoidal (TNTS) resection of pituitary tumors involves wide fluctuation in hemodynamic parameter and causes hypertension and tachycardia due to intense noxious stimuli during various stages of surgery. None of routinely used anesthetic agents effectively blunts the undesirable hemodynamic responses, and therefore usually there is a need to use increased doses of anesthetic agents. Dexmedetomidine (DEX) an alpha-2 adrenergic receptor agonist, because its sympatholytic and antinociceptive properties may ensure optimal intraoperative hemodynamic stability during critical moments of surgical manipulation. In addition, DEX reduced the anesthetic requirement with rapid recovery at the end of surgery. The main aim of our study was to evaluate the effect of DEX on perioperative hemodynamics, anesthetic requirements, and recovery characteristics in patients undergoing TNTS resection of pituitary tumors. Materials and Methods: Forty-six patients scheduled for elective TNTS resection of pituitary tumor were randomized to receive a continuous infusion of DEX (group D) or 0.9% saline (group C). Patients in both the groups were subjected to a standardized anesthesia comprising of induction with propofol, fentanyl, vecuronium, and positive pressure ventilation with O-2/air (1: 1)/isoflurane. The response entropy target range during maintenance of anesthesia was 40 to 60. The hemodynamic variables at various stages of surgery, intraoperative anesthetic, and analgesic and recovery characteristics were recorded. Results: Total fentanyl consumption during the study period was significantly lower in group D compared with group C (4.7 and 7.7 mu g/kg, respectively; P < 0.01). End-tidal isoflurane concentration requirement was found to be significantly reduced in group D compared with group C throughout the surgical period. Fentanyl and end-tidal isoflurane concentration requirement was reduced in group D compared with group C by 40% and 33.3%, respectively. Heart rate and mean arterial pressure were significantly higher in the group C compared with group D after intubation, during various stages of surgery and immediately after extubation. The group D had excellent surgical conditions and lesser bleeding in comparison to group C. Emergence time and extubation time were significantly shorter in group D compared with group C. Conclusions: DEX as an anesthetic adjuvant improved hemodynamic stability and decreased anesthetic requirements in patients undergoing TNTS resection of pituitary tumor. In addition, DEX provided better surgical field exposure conditions and early recovery from anesthesia.
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    Effect of Loading Dose of Dexmedetomidine on Dynamic Cerebral Blood Flow Autoregulation in Patients With Intracranial Glial Neoplasms
    (JOURNAL OF NEUROSURGICAL ANESTHESIOLOGY, 2015) Arulvelan, A; Manikandan, S; Easwer, HV; Krishnakumar, K
    Background: Dexmedetomidine has been widely used in neuroanesthesia and critical care settings. The effects of dexmedetomidine on cerebral vascular autoregulation and hemodynamics in patients with intracranial pathology are not well defined. This study is aimed to address this issue. Methods: Fifteen patients with unilateral supratentorial glial tumor (group S) and 15 patients without any intracranial pathology (group C) were included in this study. Transient hyperemic response testing was conducted bilaterally in both groups with transcranial color Doppler. Dynamic autoregulation was assessed with transient hyperemic response ratio (THRR) and strength of autoregulation (SA) at baseline and after infusion of inj. dexmedetomidine (1 mcg/kg) over 10 minutes. Results: THRR and SA values in the hemisphere that had tumor (group S) showed no difference from baseline after a loading dose of dexmedetomidine (P=0.914, 0.217). In the nontumor hemisphere of group S and in both the hemispheres of group C, significant reduction in THRR and SA values were observed (P<0.001) after administration of a loading dose of dexmedetomidine. THRR values were higher in the tumor hemisphere when compared with the nonpathologic hemispheres (P<0.001), suggesting the possibility of baseline hyperemia. Conclusions: In the hemisphere that had glial tumor, autoregulatory indices showed no significant change after dexmedetomidine. It can be because of abnormal vascular architecture and its altered reactivity to dexmedetomidine, or because of baseline hyperemia itself, but the exact mechanism needs to be elucidated. In the nonpathologic hemispheres, THRR and SA values were decreased, suggesting impaired autoregulation with the use of loading dose of dexmedetomidine.
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    Extraventricular neurocytoma, a comprehensive review
    (ACTA NEUROCHIRURGICA, 2014) Patil, AS; Menon, G; Easwer, HV; Nair, S
    Extra ventricular neurocytoms (EVN) are a rare parenchymal brain tumour distinct from central neurocytomas. This review attempts to analyze a series of seven cases of EVN from a single institute against the background of available literature. Retrospective analysis of the clinical manifestation, pathological features, imaging findings, microsurgical treatment effectiveness and progression free survival of seven cases of EVN operated between 2000-2012. The study group included five females and two males in the age group 7-65 years (mean 30.71 yrs). The distribution of the lesion was as follows Lobar 4, Cerebellum 1, Pineal 1, spinal 1. The duration of clinical symptoms ranged from three months to seven years and the presentation was site and size specific. Cystic Changes (71 %), perilesional oedema (57 %) and heterogeneous contrast enhancement (85.7 %), and calcification (42 %) were a few distinct imaging characteristics. Increased perfusion correlated with atypical histology in two patients. Surgical resection remains the main management strategy for longer outcome and patients with STR + RT and GTR had comparable follow-up. Extremes of age and atypical histological features were adverse prognostic factors. EVN are rare tumors with either glial or neuronal differentiation or a potential for atypical changes. Both, GTR and STR combined with RT, offer reasonably good outcome with overall comparable survival. The available literature of EVN is limited, larger series with long term follow-ups are needed to dictate the management protocol. The role of adjuvant therapy is still debatable and needs further validation.
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    Intramedullary spinal cord glial tumours: Management philosophy and surgical outcome
    (MINIMALLY INVASIVE NEUROSURGERY AND MULTIDISCIPLINARY NEUROTRAUMATOLOGY, 2006) Nair, S; Menon, G; Rao, BRM; Rajesh, BJ; Muthurethinam, T; Mathew, A; Easwer, HV; Bhattacharya, RN
    A retrospective analysis of 88 consecutive cases of intramedullary glial tumours, which constituted 58% of 149 cases of intramedullary lesions surgically managed over a 22-year period, is presented. Fifty-six astrocytomas and 32 ependymomas formed the group, which comprised 55 males and 33 females. While majority of the astrocytomas were in the cervical or cervicodorsal location (70%), it was almost equally distributed between the cervical and conus regions in 23 cases of ependymomas. The management philosophy has changed over the years from biopsy to total removal for ependymomas and a generous inside out decompression in case of astrocytomas. While only a biopsy or decompression was done in 35 of the earlier patients of astrocytomas a radical removal (subtotal in 18 and total in 3) could be achieved in 21 of our recent patients. We could achieve total resection in all the last 17 patients of ependymomas. Low grade astrocytomas radically removed and all ependymomas were not given radiotherapy. Out of the 39 patients of astrocytomas who are in follow up, 13 have improved, 19 remaining static and 7 have deteriorated. While only three of the 25 patients of ependymomas on long term follow up have deteriorated 18 have improved and 6 are remaining static. Conclusion: Although total resection of ependymomas have become a procedure with good functional results in most hands, a radical resection can be achieved with long term stabilisation of neurological deficits in majority of astrocytomas.
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    Lack of association of Lysyl oxidase (LOX) gene polymorphisms with intracranial aneurysm in a south Indian population
    (MOLECULAR BIOLOGY REPORTS, 2013) Sathyan, S; Koshy, L; Lekshmi, KRS; Easwer, HV; Premkumar, S; Alapatt, JP; Nair, S; Bhattacharya, RN; Banerjee, M
    Intracranial aneurysm (IA) accounts for 85 % of haemorrhagic stroke and is mainly caused due to weakening of arterial wall. Lysyl oxidase (LOX) is a cuproenzyme involved in cross linking structural proteins collagen and elastin, thus providing structural stability to artery. Using a case-control study design, we tested the hypothesis whether the variants in LOX gene flanking the two LD block, can increase risk of aSAH among South Indian patients, either independently, or by interacting with other risk factors of the disease. SNPs were genotyped by fluorescence-based competitive allele-specific PCR (KASPar) chemistry. We selected 200 radiologically confirmed aneurysmal cases and 235 ethnically and age and gender matched controls from the Dravidian Malayalam speaking population of South India. We observed marked interethnic differences in the genotype distribution of LOX variants when compared to Japanese and African populations. However, there was no significant association with any of the LOX variants with IA. This study also could not observe any significant role of LOX polymorphisms in influencing IA either directly or indirectly through its confounding factors such as hypertension and gender in South Indian population.
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    Pathogenesis of intracranial aneurysm is mediated by proinflammatory cytokine TNFA and IFNG and through stochastic regulation of IL10 and TGFB1 by comorbid factors
    (JOURNAL OF NEUROINFLAMMATION, 2015) Sathyan, S; Koshy, LV; Srinivas, L; Easwer, HV; Premkumar, S; Nair, S; Bhattacharya, RN; Alapatt, JP; Banerjee, M
    Background: Intracranial aneurysm (IA) is often asymptomatic until the time of rupture resulting in subarachnoid hemorrhage (SAH). There is no precise biochemical or phenotype marker for diagnosis of aneurysm. Environmental risk factors that associate with IA can result in modifying the effect of inherited genetic factors and thereby increase the susceptibility to SAH. In addition subsequent to aneurismal rupture, the nature and quantum of inflammatory response might be critical for repair. Therefore, genetic liability to inflammatory response caused by polymorphisms in cytokine genes might be the common denominator for gene and environment in the development of aneurysm and complications associated with rupture. Methods: Functionally relevant polymorphisms in the pro-and anti-inflammatory cytokine genes IL-1 complex (IL1A, IL1B, and IL1RN), TNFA, IFNG, IL3, IL6, IL12B, IL1RN, TGFB1, IL4, and IL10] were screened in radiologically confirmed 220 IA patients and 250 controls from genetically stratified Malayalam-speaking Dravidian ethnic population of south India. Subgroup analyses with genetic and environmental variables were also carried out. Results: Pro-inflammatory cytokines TNFA rs361525, IFNG rs2069718, and anti-inflammatory cytokine IL10 rs1800871 and rs1800872 were found to be significantly associated with IA, independent of epidemiological factors. TGFB1 rs1800469 polymorphism was observed to be associated with IA through co-modifying factors such as hypertension and gender. Functional prediction of all the associated SNPs of TNFA, IL10, and TGFB1 indicates their potential role in transcriptional regulation. Meta-analysis further reiterates that IL1 gene cluster and IL6 were not associated with IA. Conclusions: The study suggests that chronic exposure to inflammatory response mediated by genetic variants in pro-inflammatory cytokines TNFA and IFNG could be a primary event, while stochastic regulation of IL10 and TGFB1 response mediated by comorbid factors such as hypertension may augment the pathogenesis of IA through vascular matrix degradation. The implication and interaction of these genetic variants under a specific environmental background will help us identify the resultant phenotypic variation in the pathogenesis of intracranial aneurysm. Identifying genetic risk factors for inflammation might also help in understanding and addressing the posttraumatic complications following the aneurismal rupture.
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    Pathogenesis of intracranial aneurysm is mediated by proinflammatory cytokine TNFA and IFNG and through stochastic regulation of IL10 and TGFB1 by comorbid factors (vol 12, 135, 2015)
    (JOURNAL OF NEUROINFLAMMATION, 2015) Sathyan, S; Koshy, LV; Srinivas, L; Easwer, HV; Premkumar, S; Nair, S; Bhattacharya, RN; Alapatt, JP; Banerjee, M
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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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    Risk Factors for Aneurysmal Subarachnoid Hemorrhage in an Indian Population
    (CEREBROVASCULAR DISEASES, 2010) Koshy, L; Easwer, HV; Premkumar, S; Alapatt, JP; Pillai, AM; Nair, S; Bhattacharya, RN; Banerjee, M
    Background: Aneurysmal subarachnoid hemorrhage (aSAH) has a mortality rate as high as 50%. The prevalence of intracranial aneurysms from various parts of India varies from 0.75 to 10.3%, with higher numbers of cases being diagnosed due to the increasing age of the population and improvements in imaging techniques. However, little is known about the attributable risk factors of aSAH in the Indian population. Methods: Using a case-control study we estimated the risk of factors such as hypertension, cigarette smoking, alcohol consumption, diabetes mellitus and family history of aSAH in a South Indian population. The population-attributable risk ( PAR) of smoking, hypertension and alcohol use was estimated for the South Indian as well as for the general Indian population. Results: Our results showed that cigarette smoking ( OR, 3.59; p < 0.001) and a history of hypertension ( OR, 2.98; p < 0.001) were significant risk factors associated with aSAH. When patients were classified by gender, it was observed that being a smoker and having hypertension increased the risk for aSAH by nearly fourfold in men. Among women, hypertension and older age were significant risk factors. The PAR estimates indicated that smoking ( OR, 3.59; 95% CI, 2.13-6.06) and hypertension ( OR, 2.98; 95% CI, 1.73-5.12) are significant risk factors. Conclusions: Hypertension and smoking may be causal risk factors which might also modify the effect of genetic factors that could increase susceptibility to aSAH in the Indian population. Since these risk factors are amenable to effective modification, our findings will be useful for a gender-specific management of aSAH. Copyright (C) 2010 S. Karger AG, Basel
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    Role of endothelial nitric oxide synthase gene polymorphisms in predicting aneurysmal subarachnoid hemorrhage in South Indian patients
    (DISEASE MARKERS, 2008) Koshy, L; Easwer, HV; Neetha, NV; Natarajan, C; Bhattacharya, RN; Banerjee, M
    Endothelial nitric oxide synthase (eNOS) gene polymorphisms have been implicated as predisposing genetic factors that can predict aneurysmal subarachnoid hemorrhage (aSAH), but with controversial results from different populations. Using a case-control study design, we tested the hypothesis whether variants in eNOS gene can increase risk of aSAH among South Indian patients, either independently, or by interacting with other risk factors of the disease. We enrolled 122 patients, along with 224 ethnically matched controls. We screened the intron-4 27-bp VNTR, the promoter T-786C and the exon-7 G894T SNPs in the eNOS gene. We found marked interethnic differences in the genotype distribution of eNOS variants when comparing the South Indian population with the reported frequencies from Caucasian and Japanese populations. Genotype distributions in control and patient populations were found to be in Hardy-Weinberg equilibrium. In patients, the allele, genotype and estimated haplotype frequencies did not differ significantly from the controls. Multiple logistic regression indicated hypertension and smoking as risk factors for the disease, however the risk alleles did not have any interaction with these risk factors. Although the eNOS polymorphisms were not found to be a likely risk factor for aSAH, the role of factors such as ethnicity, gender, smoking and hypertension should be evaluated cautiously to understand the genotype to phenotype conversion.
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    Treatment of Classical Trigeminal Neuralgias – Our Experience at the Sree Chitra Tirunal Institute for Medical Sciences and Technology
    (SCTIMST, 2024-06-01) Easwer, HV
    Trigeminal Nerve is the fifth of the cranial nerves capturing sensations over face and helping us chew the food that we eat. Trigeminal Neuralgia is a condition where an aberrant neuronal activity in the nerve leads to pain over the face. This pain comes in shock-like manner lasting a minute or more in a recurrent fashion. Also called “Suicide Disease” the pain drives the sufferer to contemplate ending one’s life. Classical Trigeminal Neuralgia is due to an artery compressing the nerve. The treatment of this condition is initially using medicines which often gives relief for some time. As the frequency and intensity of the pain increases despite multiple medications. Each in increasing doses, other treatment options are contemplated. The definitive treatment of Trigeminal Neuralgia is by separating the offending artery from the nerve and positioning a piece of Teflon between the two, a. procedure called. as Microvascular Decompression (MVD). The other treatment options of Trigeminal Neuralgia includes damaging the Trigeminal Nerve partially so that pain sensation is not transmitted. This list includes – Radiofrequency Thermal Rhizotomy (RFTR) Balloon Rhizotomy and Glycerol Rhizotomy. Radiosurgery is a form of focused radiation that can be used for partially damaging the nerve using radiation This presentation details the experience of Sree Chitra Tirunal Institute for Medical Sciences and Technology in attempting to provide relief to patients with Trigeminal Neuralgia with Micro Vascular Decompression (MVD), Radiofrequency Thermal Rhizotomy (RFTR) and Balloon Compression Rhizotomy (BCR) in the last few years Acknowledgement : Easwer HV1, Krishnakumar K, George C.Vilanilam, Jayanand B Sudhir, Prakash Nair, Ganesh Divakar, Gowtham M, Subin Sukesan2 [1 Department of Neurosurgery, SCTIMST, Trivandrum, 2 Department of Cardiac Anesthesia]
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    Women and Neuroscience Publishing: Is the Gender Gap closing in?
    (NEUROLOGY INDIA, 2016) Vilanilam, GC; Easwer, HV; Vimala, S; Radhakrishnan, A; Devi, BI; Nair, SN