Sampath Somanna

The incidence of postoperative meningitis in neurosurgery: An institutional experience

INTRODUCTION Meningitis is the most dreaded cause of morbidity and mortality in neurosurgical patients. The reported incidence of postoperative meningitis is quite varied 0.5-8%. MATERIAL AND METHODS The study cohort included all the patients who underwent neurosurgery at the department of neurosurgery, National Institute of Mental Health and Neurological Sciences, Bangalore, India over a period of seven years (2001 - 2007). Patients with culture positive meningitis were included for analysis. The incidence of postoperative meningitis was analyzed depending on the type of surgery performed and the microbiological profile of the organisms, and their sensitivity pattern. RESULTS Of the 18,092 patients who underwent neurosurgical procedures during the study period, 415 patients developed infection. The overall incidence of meningitis was 2.2%. The incidence of meningitis was high (7.7%) in patients who had a pre-existing infection like post-pyogenic meningitis or tuberculosis hydrocephalus. The procedure mainly performed in this subgroup was shunt. The most common organisms causing meningitis were non-lactose fermenting Gram-negative bacillus followed by Pseudomonas and Klebsiella species. The methicillin-resistant Staphylococcus aureus strains were isolated in 2.6% of the patients. Ninety-one strains were multi-drug resistant, among which four strains were resistant to all antibiotics tested. The overall mortality in patients with meningitis was 5%. CONCLUSION Meningitis remains one of the most dreaded complications of neurosurgical procedures and is common in patients with preexisting infection. Gram-negative organisms are the most common causative pathogens of postoperative meningitis.

The role of decompressive craniectomy in cerebral venous sinus thrombosis

OBJECT Studies on the role of decompressive craniectomy for cerebral venous sinus thrombosis (CVST) in the literature are scanty. Randomized trials face a lot of drawbacks, including ethical issues. In this article the authors discuss their experience with this procedure for CVST and review the available literature. METHODS This study was a retrospective analysis of all patients who underwent decompressive craniectomy for CVST between August 2006 and June 2008 at the National Institute of Mental Health and Neurosciences. The cases were evaluated for demographic and clinicoradiological features, operative findings, and outcome of surgery. Ethical clearance was obtained from the institutional ethics committee. The data for each patient were obtained from the database of the department. Follow-up data were obtained either through direct clinical evaluation or mailed self-report questionnaire. The Glasgow Outcome Scale (GOS) and the Rankin Disability Scale were used to assess the outcome. RESULTS A total of 34 patients (13 men and 21 women) were included; their mean age was 31.6 years, with a range from 18 to 65 years. In univariate analysis, the Glasgow Coma Scale (GCS) score prior to surgery and that in the immediate postoperative period had a statistically significant correlation with poor outcome. The GCS score immediately postoperatively was the only independent, significant predictor of poor outcome on multivariate analysis. CONCLUSIONS Decompressive craniectomy in a selected cohort of patients had a good outcome in a majority of the patients: 26 of 34 in this study had a GOS score of 4 or 5. In this series, which is the largest in the available literature, the authors review their experience and recommend usage of this procedure in selected patients.

Spinal osteochondroma: spectrum of a rare disease

Osteochondromas are the most common benign bone tumor. Although the metaphysial region of long bones is the usual site of these tumors, the vertebrae may be infrequently affected. The presentation may vary from typical compressive myelopathy to radiculopathy or radiculomyelopathy, depending on the site of involvement. The authors present 3 consecutive cases of cervical spine osteochondromas encountered over 3 years at their institution, each different in its site of involvement, presentation, and chosen treatment. The patient in Case 1 had the typical presentation and lesion site, and was treated with a conventional laminectomy. The patient in Case 2 presented with an extensive disease that required complex, staged surgery with spinal fusion and instrumentation. The patient in Case 3 presented with monoradiculopathy and had a facet joint osteochondroma that was successfully treated with a simple partial facetectomy, without laminectomy.

Outcome of ventriculoperitoneal shunt placement in Grade IV tubercular meningitis with hydrocephalus: a retrospective analysis in 95 patients. Clinical article.

OBJECT Hydrocephalus is the most common complication of tubercular meningitis (TBM). Relieving hydrocephalus by ventriculoperitoneal (VP) shunt placement has been considered beneficial in patients in Palur Grade II or III. The role of VP shunt placement in those of Grade IV is controversial and the general tendency is to avoid its use. Some authors have suggested that patients in Grade IV should receive a shunt only if their condition improves with a trial placement of an external ventricular drain (EVD). In the present study, the authors assessed the outcome of VP shunt placement in patients in Grade IV TBM with hydrocephalus to examine the factors predicting outcome and to determine whether a trial with an EVD is absolutely necessary prior to shunt placement. METHODS Ninety-five consecutive cases of TBM with hydrocephalus in which the patients underwent VP shunt placement were retrospectively analyzed, and direct VP shunts were placed whenever possible. An EVD was placed first only in the presence of deranged blood parameters. Outcomes were assessed both in the short and long term. RESULTS The mean patient age was 17.5 years (range 1-55 years). Fifty-two patients underwent direct VP shunt placement, and the remaining 43 received EVDs first. Overall, 33 and 45% of patients had favorable short- and long-term outcomes, respectively. Age older than 3 years and duration of altered sensorium < or = 3 days were predictive of a favorable short-term outcome. Glasgow Coma Scale score at presentation was predictive of long-term outcome. Of the patients who did not improve with placement of an EVD prior to VP shunt insertion, 24 and 18% had favorable short- and long-term outcomes, respectively; this was not significantly different from the outcome in the patients who underwent direct VP shunt placement. CONCLUSIONS Direct VP shunt placement is an effective option in patients with Grade IV TBM with hydrocephalus. Age and duration of altered sensorium are predictive of short-term outcome, while Glasgow Coma Scale score at presentation predicts long-term outcome. Ventriculoperitoneal shunts should be considered even in patients who do not improve with an EVD.

Focal intradural brain infections in children: an analysis of management and outcome.

Introduction: Focal intradural infections of the brain include empyema and abscess in the supratentorial and infratentorial spaces. These are amenable to surgical management. Various other issues may complicate the course of management, e.g. hydrocephalus with infratentorial lesions or cortical venous thrombosis with supratentorial lesions. Here, we review the management and identify factors affecting outcome in these patients. Materials and Methods: This is a retrospective analysis of all children (aged <18 years) treated at the National Institute of Mental Health and Neurosciences, Bangalore, India, between 1988 and 2004. Case records were analyzed to obtain clinical, radiological, bacteriological and follow-up data. Results: There were 231 children who underwent treatment for focal intradural abscess/empyema at our institute. These included 57 children with cerebral abscess, 65 with supratentorial empyema, 82 with cerebellar abscess and 27 with infratentorial empyema. All patients underwent emergency surgery (which was either burr hole and aspiration of the lesion or craniotomy/craniectomy and excision/evacuation), along with antibiotic therapy, typically 2 weeks of intravenous and 4 weeks of oral therapy. The antibiotic regimen was empiric to begin with and was altered if any sensitivity pattern of the causative organism(s) could be established by culture. Hydrocephalus was managed with external ventricular drainage initially and with ventriculoperitoneal shunt if warranted. Mortality rates were 4.8% for cerebral abscess, 9.6% for cerebellar abscess, 10.8% for supratentorial subdural empyema and 3.7% for posterior fossa subdural empyema. The choice of surgery was found to have a strong bearing on the recurrence rates and outcome in most groups, with aggressive surgery with craniotomy leading to excellent outcomes with a low incidence of residual/recurrent lesions. Conclusions: Antibiotic therapy, emergency surgery and management of associated complications are the mainstays of treatment of these lesions. We strongly advocate early, aggressive surgery with antibiotic therapy in children with focal intradural infections.

Methicillin-Resistant Staphylococcus aureus central nervous system infections - Analysis and outcome

Abstract Introduction. Methicillin-Resistant Staphylococcus aureus (MRSA)-associated infections are potentially devastating and fatal. It has two distinct pathogenic mechanisms: postoperative and spontaneous. In the study presented here, we review the epidemiology, clinical features, response to treatment, and outcome of MRSA central nervous system infections at our tertiary referral institute. Material and methods. In this analysis, we reviewed the medical records of all patients who were diagnosed with S. aureus meningitis between January 2010 and December 2012. Clinical information included predisposing factors, past medical history, comorbidities, mode of acquisition of infection, as well as therapeutic management, length of treatment, and clinical outcomes were analyzed. Results. A total of 34 cases of MRSA meningitis were diagnosed during the study period. There were 28 (82.4%) cases of postoperative meningitis and 6 (17.6%) cases of spontaneous meningitis. A majority (24/28) of the patients had one or the other predisposing conditions for the infection. Compared with patients with postoperative meningitis, patients with spontaneous meningitis had a significantly older (31.93 yrs vs 55.8 yrs; p = 0.021) and higher frequency of community-acquired infection (100% vs. 39%; p = 0.007). In patients with postoperative meningitis, the median postoperative day when the infection manifested clinically was day- 19 (range, 3–90 days). A total of 25/34 (74%) patients received definitive antibiotic (vancomycin and/or linezolid based) therapy. Nine patients were continued on empirical antimicrobial therapy (combination of ceftriaxone, amikacin, and metronidazole), as the organism was sensitive to those drugs. There were no in-hospital mortalities in our series, though 3/34 patients (8.8%) were discharged with Glasgow coma score (GCS)< 8 and 8/34 patients (23.5%) were discharged with GCS 9–12 from the hospital. Conclusion. In acute bacterial meningitis, there is a progressive shift from methicillin-sensitive strains to methicillin-resistant strains in recent years. Although most patients have a favorable response to vancomycin and linezolid, the beneficial effect of combined antimicrobial therapy or alternative antibiotics needs to be evaluated.

Mixed-density extradural hematomas on computed tomography-prognostic significance

BACKGROUND It has been variably reported that patients who acutely present with low- or mixed-density blood on CT scan are associated with poor clinical outcome. The aim of the study was to correlate the presence or absence of mixed density within EDHs on CT scanning with the clinical outcome. METHODS This is a retrospective study of a total of 109 patients with EDHs who were operated on from August 2001 to August 2002. The CT scans were reviewed and classified into 2 categories-predominantly hyperdense and mixed density. This was correlated with clinical details and outcome. RESULTS In all, 43.2% (16/37) of patients in the mixed-density category presented with GCS of no more than 8 as compared with 23.6% (17/72) of patients in the hyperdense group (P < .05). Mean hematoma volume in the mixed-density group was 72 cm(3) as compared with 42 cm(3) in the hyperdense group (P < .05). Mortality rate was significantly higher in the mixed-density category (21.6% vs 4.2%, P < .05). CONCLUSION The study portends mixed density in EDH as a potent poor prognostic indicator. The mixed density of the clot probably indicates that the clot is rapidly increasing in size and requires even earlier and more aggressive treatment.

Recurrence in medulloblastoma - influence of clinical, histological and immunohistochemical factors.

Introduction. The therapy for medulloblastomas has gone through several changes over the years. Research has shown that patients with medulloblastoma cannot be satisfactorily stratified into risk groups based on clinical and therapeutic factors alone. Aim. To study the clinical, histological features and expression of immunohistochemical markers in medulloblastoma, and to correlate these features with recurrence rates. Materials and methods. Sixty-three cases of medulloblastomas operated at our institute from 1996–2003 were selected and retrospectively analyzed for therapy received, histological features and immunohistochemical expression of GFAP, synaptophysin, erb B2, p53, Bcl-2 and Trk-C along with assessment of MIB-1 labeling index(LI). Results. The mean age of the 63 cases at presentation was 11.6 yrs. Near/Gross- total resection was achieved in 74.6% (47/63) of the cases. Conclusion. We propose a clinical-histological-immunohistochemical’ model for medulloblastoma where extent of resection, administration of chemotherapy, presence of gross anaplasia and c-erb B2 overexpression status are the most important predictors of recurrence rates.

Unusual complications of a benign tumour – our experience with midline posterior fossa epidermoids

Abstract Epidermoids of the brain are uncommon benign tumours. Their midline posterior fossa location is exceedingly rare. Fifteen patients with this condition were operated during a 14-year period. Majority of the patients presented in their middle age with mean duration of symptoms of 10 months. Gait imbalance was the commonest symptom observed. Seven patients had features suggestive of raised intracranial tension. Computed tomography scanning showed typical hypodense lesions. On MRI, tumours were hypo-intense on T1 weighted images and hyper-intense on T2 weighted images. All patients underwent microsurgical excision. We encountered certain complications in the post-operative period. This prompted us for a review of our case material and literature and is the basis of the present article. Implications of these findings are discussed.

Aneurysms from extracranial, extradurally originating posterior inferior cerebellar arteries: a rare case report

BACKGROUND Aneurysms arising from the PICA are infrequent and those arising from an extracranially originating PICA in the extracranial intradural region are even rare. We report a case of bilaterally extracranial extradurally originating PICAs, each of which had an aneurysm, both being situated below the foramen magnum. This to the best of our knowledge is the first of its kind to be reported. CASE DESCRIPTION A 35-year-old woman presented with giddiness and headache of 2-day duration. CT scan head revealed blood in the 4(th) ventricle. 4 vessel angiogram revealed bilateral extracranial, extradural origin of PICAs from the vertebral arteries between C1 and C2 vertebrae. Both PICAs were associated with a saccular aneurysm each, both of which were extracranial. She underwent a midline suboccipital craniectomy, C1 arch excision, and clipping of both aneurysms. CONCLUSIONS We report a very rare case of bilateral extracranial PICA aneurysms from an aberrantly originating PICA (ie, extracranial and extradural).