Study Design Retrospective cohort study. Objectives Intraoperative neurophysiological monitoring (IONM) is widely used in spinal neurosurgery, particularly for intramedullary tumours. However, its validity in intradural extramedullary (IDEM) spinal tumours is less clearly defined, this being the focus of this study. Methods We compared outcomes for patients that underwent resection of IDEM tumours with and without IONM between 2010 and 2020. Primary outcomes were postoperative American Spinal Injury Association (ASIA) scores. Other factors assessed were use of intraoperative ultrasound, drain placement, postoperative complications, postoperative Eastern Cooperative Oncology Group (ECOG) score, extent of resection, length of hospital stay, discharge location and recurrence. Results 163 patients were included, 71 patients in the IONM group and 92 in the non-IONM group. No significant differences were noted in baseline demographics. For preoperative ASIA D patients, 44.0% remained ASIA D and 49.9% improved to ASIA E in the IONM group, compared to 39.7% and 30.2% respectively in the non-IONM group. For preoperative ASIA E patients, 50.3% remained ASIA E and 44.0% deteriorated to ASIA D in the IONM group, compared to 30.2% and 39.7% respectively in the non-IONM group (all other patients deteriorated further). Length of inpatient stay was significantly shorter in the IONM group ( P = .043). There were no significant differences in extent of resection, postoperative complications, discharge location or tumour recurrence. Conclusions Research focusing on the use of IONM in IDEM tumour surgery remains scarce. Our study supports the use of IONM during surgical excision of IDEM tumours.

Arachnoid cysts are CSF-containing entities that rarely are symptomatic or warrant neurosurgical intervention. In addition, infection of these lesions is an even rarer event, with only four reports in the literature capturing this. In this report, we present the case of a 79-year-old man presenting with paraparesis, secondary to a right parasagittal meningioma, with an incidental asymptomatic right sylvian arachnoid cyst (Galassi type II). The initially planned surgery was postponed for 3 months, due to COVID-19 restrictions, and he was kept on high dose of steroids. Following tumour resection, the patient developed bilateral subdural empyemas with involvement of the arachnoid cyst, requiring bilateral craniotomies for evacuation of the empyemas and drainage of the arachnoid cyst. Suppuration of central nervous system arachnoid cysts is a very rare complication following cranial surgery with the main working hypotheses including direct inoculation from surrounding inflamed meninges or haematogenous spread secondary to systemic bacteraemia, potentiated by steroid-induced immunosuppression. Even though being a rarity, infection of arachnoid cysts should be considered in immunosuppressed patients in the presence of risk factors such as previous craniotomy.

Objectives: Cerebrospinal fluid (CSF) leak following endoscopic transsphenoidal surgery (TSS) remains a challenge and is associated with high morbidity. We perform a primary repair with fat in the pituitary fossa and further fat in the sphenoid sinus (FFS). We compare the efficacy of this FFS technique with other repair methods and perform a systematic review. Design, patients, and methods: Retrospective analysis of patients undergoing standard TSS from 2009 to 2020, comparing the incidence of significant postoperative CSF rhinorrhoea (requiring intervention) using the FFS technique compared with other intraoperative repair strategies. Systematic review of current repair methods described in the literature was performed following the PRISMA guidelines. Results: 439 patients; 276 patients multilayer repair, 68 FFS repair and 95 no repair. No significant differences in baseline demographics between groups. Postoperative CSF leak requiring intervention was significantly lower in the FFS repair group (4.4%) compared to the multilayer (20.3%) and no repair groups (12.6%, p<0.01). This translated to fewer reoperations (2.9% FFS vs. 13.4% multilayer vs 8.4% no repair, p<0.05), fewer lumbar drains (2.9% FFS vs. 15.6% multilayer vs. 5.3% no repair, p<0.01) and shorter hospital stay (median days 4 (3-7) FFS vs. 6 (5-10) multilayer vs. 5 (3-7) no repair, p<0.01). Risk factors for postoperative leak included female gender, perioperative lumbar drain, and intraoperative leak. Conclusions: Autologous fat on fat graft for standard endoscopic transsphenoidal approach effectively reduces the risk of significant post-operative CSF leak with reduced reoperation and shorter hospital stay.