The impact of spinal anaesthesia on perioperative opioid consumption, postoperative pain and oncological outcome in radical retropubic prostatectomy—a retrospective before-and-after effectiveness study

BACKGROUND: Spinal anaesthesia preceding general anaesthesia has been conducted for open radical retropubic prostatectomy (RRP) to decrease immediate postoperative pain for many years. Nevertheless, the effectiveness of spinal anaesthesia to reduce postoperative opioid requirements remains unknown. The aim of the present study was to determine the effect of spinal anaesthesia preceding general anaesthesia on opioid requirements, postoperative pain and biochemical cancer-free survival. METHODS: This before-and-after effectiveness study investigated effects of two different anaesthesia techniques in 636 patients with RRP. Three hundred eighteen consecutive patients in the SPA group (spinal anaesthesia preceding general anaesthesia) were compared with 318 patients in the GA group (general anaesthesia alone). The primary endpoint of the study was opioid consumption in the post-anaesthesia care unit. Secondary endpoints were intraoperative opioid consumption, postoperative pain, postoperative recovery time, the length of hospital-stay, persistence of pain 1 year after surgery and cancer-free survival. Differences between the groups were analysed by a two-sided t-test, χ(2)-test, Fisher’s exact test and Mann–Whitney U test and the influence of possible confounders on opioid consumption with a general linear model. Cancer-free survival was determined by Kaplan–Meier curves and group differences by log-rank tests and multivariable Cox regression analyses. RESULTS: The total amount of morphine equivalent administered postoperatively was 7.5 [6.9; 8.1] mg in the SPA group and 6.0 [5.5; 6.5] mg in the GA group (mean [95% CI], p < 0.001). The amount of intraoperative sufentanil was 56.9 [55.1; 58.7] μg in the SPA group and 84.5 [82.5; 86.5] μg in the GA group (mean [95% CI], p < 0.001). There was no difference found in the postoperative pain level, length of hospital-stay and pain level 1 year after surgery. Biochemical cancer-free survival was highly related to TNM stage (p < 0.001, pT3 vs. pT2 hazard ratio 5.4 [95%CI 3.3; 9.2]) but not to the type of anaesthesia (p = 0.29). CONCLUSIONS: Spinal anaesthesia preceding general anaesthesia for RRP is associated with increased postoperative opioid consumption compared to general anaesthesia alone. Postoperative pain level and the oncological outcome are not affected by the adjunctive use of spinal anaesthesia. Thus, the addition of spinal anaesthesia to general anaesthesia has no advantage in RRP. TRIAL REGISTRATION: ClinicalTrial.gov, NCT03565705.