Contemporary outcomes and prediction of adherent perinephric fat at partial nephrectomy: a systematic review

Objective: Current guidelines recommend partial nephrectomy for the management of T1a tumours. Adherent perinephric fat (APF) has been recognized as a complicating feature of such surgery. The objective of this article was to present a systematic review of the published literature investigating APF aetiology, risk factors and outcomes.Materials and methods: To identify relevant studies, the PubMed, MEDLINE, Web of Science and Google Scholar databases were searched from 1990 to 2017.Results: Eight studies studying APF were identified. The aetiology of APF appears to be multifactorial, but is thought to be associated with a systemic, chronic inflammatory state secondary to metabolic syndrome. Several risk factors have been identified. Clinically, APF is more prevalent in ageing and male populations, particularly those with high body mass index and waist measurements. Radiological risk factors for APF include increased perinephric fat thickness and stranding, which can be combined to produce the Mayo Adhesive Probability (MAP) score, a predictive index that has been validated in small, external cohorts. The presence of APF at partial nephrectomy is associated with increased operative time and estimated blood loss. However, there is no documented increase in warm ischaemia time or perioperative complications in patients with APF.Conclusions: More studies are required to identify outcomes and risk factors for APF. Early identification of patients with APF can allow surgeons to guide preoperative planning and patient assessment.