Malignant bihemispheric cerebral edema after cranioplasty - An extension of the Monro-Kellie doctrine and predictive factors.

Background: Several changes in normal pressure dynamics on the brain occur with a decompressive craniectomy and subsequent cranioplasty. Dead space volume is an important factor contributing to intracranial volume postcranioplasty. A decrease in this volume due to negative suction drain along with relative negative pressure on the brain with the loss of external atmospheric pressure may lead to fatal cerebral edema. Case Description: A 52-year-old gentleman with a 210 mL volume and middle cerebral artery territory infarction underwent an emergency craniectomy and 6 months later a titanium mold cranioplasty. Precranioplasty computed tomography (CT) scan evaluation revealed a sunken skin flap with a 9 mm contralateral midline shift. Immediately following an uneventful surgery, the patient had sudden fall in blood pressure to 60/40 mmHg and over a few min had dilated fixed pupils. CT revealed severe diffuse cerebral edema in bilateral hemispheres with microhemorrhages and expansion of the sunken right gliotic brain along with ipsilateral ventricular dilatation. Despite undergoing a contralateral decompressive craniectomy due to the midline shift toward the right, the outcome was fatal. Conclusion: Careful preoperative risk assessment in cranioplasty and close monitoring postprocedure is crucial, especially in malnourished, poststroke cases, with a sinking skin flap syndrome, and a long interval between decompressive craniectomy and cranioplasty. Elective preventive measures and a low threshold for CT scanning and removal of the bone flap or titanium mold are recommended.

Development and Validation of a Multivariable Model to Predict Surgical Outcome in Patients with Chiari malformations.

Background: Surgical outcome predictive models for Chiari malformations (CM) which are applicable to all age groups and simple enough to use on outpatient basis are lacking. Objective: The aim of this study was to develop and validate a preoperative index for predicting long-term outcomes in Chiari 1 (CM1) and Chiari 0 (CM0) malformations. Materials and Methods: It was a single-institution, ambidirectional, cohort study from 2014 to 2019, having patients between 5 to 70 years. Outcome was assessed using Chicago Chiari outcome score (CCOS) over 2 years follow-up. Preoperative clinical and radiological factors were analyzed using Chi-square test and Mann Whitney U test, in relation to CCOS and those attaining P value ≤0.05, were used to develop model - Chiari Outcome Predictive Index (COPI). COPI was internally validated using 10-fold cross-validation and c-statistic for discrimination. Results: A total of 88 patients (66 in development and 22 in validation cohort) were included in the study. Outcome was negatively associated with presence of motor, sensory or cranial nerve symptoms, poor functional status, basilar invagination, and tonsillar descent. It was positively associated with shorter duration of presenting symptom (<9 months) and syrinx diameter <6 mm. COPI predicted CCOS with 91.1% accuracy (10-fold cross-validation). It had excellent discrimination for improved outcome (c = 0.968 in development and 0.976 in validation cohort), at threshold index of -1. Conclusions: COPI is simple tool that can be administered in outpatient setting. It can facilitate evidence-based preoperative counseling of patients, to help them develop reasonable expectations regarding surgical outcomes.

Efficacy of stereotactic aspiration in deep-seated and eloquent-region intracranial pyogenic abscesses.

OBJECT: Intracranial abscesses located deep in the cerebral parenchyma and in eloquent regions are often difficult to manage surgically. The authors have attempted to analyze the efficacy of stereotactic aspiration in the management of these abscesses. METHODS: Cases involving 22 patients (including 9 children) with deep-seated and/or eloquent-region intracranial abscesses who underwent CT- or MR imaging-guided stereotactic aspiration between January 1995 and July 2001 were analyzed. RESULTS: A definite source of infection could be identified only in 9 of the cases. In 18 patients, the abscess was deep seated, whereas in the rest it was located in the eloquent cortex. Five patients had abscesses located in multiple sites. In 17 patients only 1 aspiration was required; in 5 others subsequent procedures were required. In the initial postaspiration CT, minor hemorrhage was noted in 3 patients not requiring further intervention. Antibiotics were administered for a period varying from 4 to 8 weeks following aspiration. An early recurrence (within 2 weeks of initial aspiration) was evident in 5 patients. All recurrent abscesses were reaspirated. In 2 patients new abscesses developed while the patients were still receiving antibiotic therapy. There were no late recurrences. In 1 patient ventriculitis developed, with subsequent hydrocephalus requiring a shunt insertion. Follow-up CT scans showed complete resolution of the abscess in all patients. There were no deaths. CONCLUSIONS: Stereotactic aspiration is a useful management option for abscesses located in eloquent or inaccessible regions. Repeated aspiration should be considered in patients in whom the initial aspiration proves ineffective or partially effective. Complete resolution may require repeated stereotactic aspirations and continued antibiotic therapy.

A rare case of cellular schwannoma involving the trigeminal ganglion.

Cellular schwannomas rarely involve the cranial nerves, being more common in the spinal and peripheral nerves. A rare case of cellular schwannoma involving the gasserian ganglion, a hitherto unreported site, that extended infratentorially to present as a cerebellopontine angle tumor is reported. It is important to recognize that cellular schwannomas can histologically mimic malignant peripheral nerve sheath tumors because of their high cellularity and mitotic activity, but they are relatively benign tumors with a tendency to recur but not metastasize.