Postoperative pain management and the incidence of ipsilateral shoulder pain following thoracic surgery at an Australian tertiary hospital: A prospective audit

Abstract Objectives Ipsilateral shoulder pain (ISP) is a common but variably occurring (42%-85%) complication post thoracic surgery. Multiple potential treatments including upper limb blocks, intrapleural local anaesthetic infiltration and systemic opioids, have been trialed with limited efficacy. Phrenic nerve infiltration is a potential intervention which may prevent ISP. The aim of this study was to assess the incidence and severity of ISP post thoracic surgery at our institution where phrenic nerve infiltration is commonly utilised. Design: Observational cohort study Setting A single centre study in a tertiary referral centre in Brisbane, Australia. Participants This study comprised all adult patients undergoing thoracic surgery at a tertiary care referral centre from May to July 2018. Measurements and Main Results Surgical procedures were divided into open thoracotomy, video-assisted thoracic surgery (VATS) and VATS-guided mini-thoracotomy. The primary outcome was a comparison of incidence of ISP between the three types of surgical procedures.  Data was analysed using Stata (StataCorp) with significance testing by Kruskal-Wallis equality of populations rank test. A p-value of Conclusion In summary, we observed a lower (15.8%) incidence of moderate to severe ISP amongst our thoracotomy patients than reported in prior literature. Injection of local anaesthetic into the phrenic nerve fat pad at the level of the diaphragm appears to be an effective and safe surgical intervention that may eliminate a significant cause of ISP. None of the VATS patients, who received phrenic nerve infiltration experienced ISP.  Post-operative pain in VATS is expected to be reduced by avoiding the use of a rib spreader, severing of the intercostal nerves, and division of muscle tissue which may account for the lower observed rates of ISP in the VATS cohort who did not receive phrenic nerve infiltration. Further randomised controlled trials are warranted to establish if patients undergo various VATS procedure benefit from this intervention.