PP31. A SYSTEMATIC REVIEW OF THE EFFECT OF CASELOAD ON OUTCOMES IN BRAIN TUMOUR SURGERY

INTRODUCTION: Hospital and surgeon case volume has been shown to impact outcomes in a number of surgical fields, including urology, gastrointestional surgery and neurosurgery. Within neurosurgery, a positive effect for high-caseload has been demonstrated for intracranial aneurysms and craniotomy for brain tumours. Plausible mechanisms for this effect have included, surgeon experience and provider effects such as improved use of intra-operative modalities which can increase resection safety. Previous studies have shown that there is trend towards increasing centralisation of care with increasing numbers of surgeries being performed at high-volume centers. This systematic review aimed to examine the existing evidence to determine the effects of volume on outcomes in brain tumour. METHODS: The MEDLINE, Embase, Cochrane Central Register of Controlled Trials and other databases were scrutinised according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) statement, using a pre-determined search strategy. All studies involving primary analysis of hospital volume and surgeon-volume on outcome in adult and paediatric brain tumour were included. RESULTS: Seven studies covering the period between 1988 to 2009 were included. All seven were retrospective cohort studies using the Nationwide Inpatient Sample (NIS) from the USA. Three studies examined mixed population of beningn and malignant pathologies, with one study focusing on supratentorial tumours (n = 62514). Two of these studies had population samples which overlapped in time (between 2001 to 2007 and between 2000 to 2009). Four studies examined focused popaulations including, meningioma, metastatic brain tumours, transphenoidal pituitary surgeries and paediatric brain tumours. Due to the heterogeneity of the populations examining combined effects was not possible. All the studies supported a beneficial effect on outcome with increasing caseload. In-hospital mortality was reduced when patients are treated at a high-volume center, OR ranged from 0.52 p = 0.03 to 0.76 p = 0.003. For patients treated by high volume surgeons the OR of in-hospital mortality ranged from 0.42 p = 0.012 to 0.62 p = 0.02. Other commonly examined outcomes included, Length of Stay, Adverse discharge deposition and Complication rate. No studies examined mortality and morbidity of patients post-discharge. CONCLUSIONS: Studies examining populations between 1988 to 2009 generally support a positive relationship