Intracranial pressure monitoring in posterior fossa lesions-systematic review and meta-analysis.

Elevated intracranial pressure (ICP) with reduced cerebral perfusion pressure is a well-known cause of secondary brain injury. Previously, there have been some reports describing different supra- and infratentorial ICP measurements depending on the location of the mass effect. Therefore, we aimed to perform a systematic review and meta-analysis to clarify the issue of optimal ICP monitoring in the infratentorial mass lesion. A literature search of electronic databases (PUBMED, EMBASE) was performed from January 1969 until February 2021 according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement. Two assessors are independently screened for eligible studies reporting the use of simultaneous ICP monitoring in the supra- and infratentorial compartments. For quality assessment of those studies, the New Castle Ottawa Scale was used. The primary outcome was to evaluate the value of supra- and infratentorial ICP measurement, and the secondary outcome was to determine the time threshold until equalization of both values. Current evidence surrounding infratentorial ICP measurement was found to be low to very low quality according to New Castle Ottawa Scale. Eight studies were included in the systematic review, four of them containing human subjects encompassing 27 patients with infratentorial pathology. The pooled data demonstrated significantly higher infratentorial ICP values than supratentorial ICP values 12 h after onset (p < 0.05, 95% CI 3.82-5.38) up to 24 h after onset (p < 0.05; CI 1.14-3.98). After 48-72 h, both ICP measurements equilibrated showing no significant difference. Further, four studies containing 26 pigs and eight dogs showed a simultaneous increase of supra- and infratentorial ICP value according to the increase of supratentorial mass volume; however, there was a significant difference towards lower ICP in the infratentorial compartment compared to the supratentorial compartment. The transtentorial gradient leads to a significant discrepancy between supra- and infratentorial ICP monitoring. Therefore, infratentorial ICP monitoring is warranted in case of posterior fossa lesions for at least 48 h.

Posterior Fossa Hemorrhage Following the Use of Low-Molecular-Weight Heparin: Lessons Learned and Recommendations for the Treatment and Prophylaxis of Postoperative Venous Thromboembolism.

Introduction Venous thromboembolism (VTE) is the most common preventable cause of morbidity and mortality among neurosurgery patients. Several studies have concluded that the use of chemical prophylaxis among patients undergoing a craniotomy reduces the incidence of VTE, and it is presumed to be safe. However, these studies do not differentiate between a supratentorial and posterior fossa craniotomy. Furthermore, the prophylactic or therapeutic use of low-molecular-weight heparin (LMWH) has been reported to increase the risk of intracranial hemorrhage. In this study, we describe the clinical details and outcomes for all patients who underwent posterior fossa craniotomy and developed posterior fossa hemorrhage secondary to postoperative use of LMWH during the study period. We also propose recommendations pertaining to postoperative heparin use after posterior fossa surgeries. Methods Data were retrospectively collected for patients presenting with posterior fossa hemorrhage following anticoagulant use among those who previously underwent posterior fossa craniotomy by the senior author (R.W.P.) from January 1, 2011, through December 31, 2018. Results We identified five patients who experienced postoperative hemorrhage while receiving LMWH in the initial setting of posterior fossa craniotomy. After hemorrhaging, four patients had low Glasgow Outcome Scale (GOS) scores (≤3) and failed to return to their baseline neurological status. These four patients had a Glasgow Coma Scale (GCS) score of 15/15 in the immediate postoperative period and received heparin within 72 hours of surgery. Conclusions Based on our findings, there is a possible association between the increased risk of hemorrhage and the early postoperative use of LMWH. The debilitating outcomes among the majority of these patients warrant the cautious use and further investigation of postoperative LMWH to appropriately quantify the risk. Further comparative studies with a larger sample size are required to provide insight into the pathophysiology of our findings.

The semisitting position: analysis of the risks and surgical outcomes in a contemporary series of 425 adult patients undergoing cranial surgery.

OBJECTIVE The objective of this study was to analyze the incidence of the primary complications related to positioning or surgery and their impact on neurological outcome in a consecutive series of patients undergoing elective surgery in the semisitting position. METHODS The authors prospectively collected and retrospectively analyzed data from adult patients undergoing elective surgery in the semisitting position for a cranial disease. Patients were managed perioperatively according to a standard institutional protocol, a standardized stepwise positioning, and surgical maneuvers to decrease the risk of venous air embolism (VAE) and other complications. Intraoperative and postoperative complications were recorded. Neurointensive care unit (NICU) length of stay (LOS) and hospital LOS were the intermediate endpoints. Neurological outcome was the primary endpoint as determined by the modified Rankin scale (mRS) score at 6 months after surgery. RESULTS Four hundred twenty-five patients were included in the analysis. VAE occurred in 90 cases (21%) and it made no significant statistical difference in NICU LOS, hospital LOS, and neurological outcome. No complication was directly related to the semisitting position, although 46 patients (11%) experienced at least 1 surgery-related complication and NICU LOS and hospital LOS were significantly prolonged in this group. Neurological outcome was significantly worse for patients with complications (p < 0.0001). CONCLUSIONS Even in the presence of intraoperative VAE, the semisitting position was not related to an increased risk of postoperative deficits and can represent a safe additional option for the benefit of specific surgical and patient needs.

Dural-Based Cavernoma of the Posterior Cranial Fossa Mimicking a Meningioma: A Case Report.

Cavernous angiomas usually occur in the parenchyma of both the supra and infratentorial compartments. At times, they can both clinically and radiologically mimic other dural-based lesions. We present a case of a patient with chronic occipital headaches, initially thought to have a meningioma, but proven to be a cavernoma with histological analysis.

Stereotaxic Transcerebellar Approach for the Posterior Fossa Lesions with C.R.W. System

6 patients underwnet CT-guided stereotactic biopsy or hematoma aspiration procedure for posterior fossa lesions. Trajectory for biopsy or aspiration was transcerebellar approach. The patients were placed under general endotracheal anesthesia and positioned prone or sitting. No complications were encountered in the postoperative period when this technique was used. Stereotaxic transcerebellar multiple biopsy can safely provide tissue conformation of the neoplastic nature of a posterior fossa lesion thought to be a tumor. In addition, hematoma aspiration has been demonstrated to be safe, reliable, and efficient.