Risk adjustment in audit of outcome after head and neck surgery applied to cumulative sum chart methodology to monitor of free flap failure

Abstract

Most surgical specialities have attempted to address the concern of unfair comparison by risk-adjusting surgical outcome data in order to benchmark speciality specific indicators of quality of care. In this paper, we update our efforts to produce a robust, validated, means of risk adjustment in key metrics by reporting past efforts and adding a further algorithm to benchmark and report free flap failure rates. A dataset of surgical care episodes, recorded as a prospective clinical audit in multiple NHS hospitals, was analysed for adverse events after surgery for head and neck squamous cell carcinoma (HNSCC). Classification models using preoperative patient demographic data, operation data, functional status data and tumour stage data, were built that predict for complications, length of hospital stay, positivity of margins and free-flap failure. Oncology and Reconstruction are two sub-speciality groups within the Oral & Maxillofacial speciality which are developing metrics within a Quality Outcome in Oral & Maxillofacial Surgery (QOMS) framework. The QOMS framework will allow meaningful comparison of quality of care delivered by surgical units in the UK. In order for metrics to be effective they must demonstrate variation between units, be amendable to change by service personnel, and have baseline data available in the literature. We argue metrics also must be able to be modelled in order that meaningful benchmarking, which takes account of variation in complexity of patient need/care, is possible.