Perioperative nerve injury after total shoulder arthroplasty: assessment of risk after regional anesthesia.

Background And Objectives: One of the most debilitating complications after total shoulder arthroplasty (TSA) is perioperative nerve injury (PNI). Interscalene blockade (ISB) improves clinical outcomes after TSA, but it may increase the risk for PNI. The objective of this large-scale, single-institution cohort study was to test the hypothesis that the use of ISB increases the risk for PNI after elective TSA.

Methods: All patients 18 years and older and undergoing primary elective TSA at Mayo Clinic Rochester between 1993 and 2007 were identified. The primary outcome was the presence of new PNI documented within 3 months of the procedural date. The frequency of PNI was summarized using point estimates, along with 95% confidence intervals (CIs) that were calculated using the Poisson approximation. Multivariable logistic regression was used to evaluate potential risk factors for PNI.

Results: A total of 1569 patients underwent elective TSA during the study period; 35 cases met criteria for PNI. The overall incidence of PNI was 2.2% (95% CI, 1.6%-3.1%). Use of ISB was associated with reduced odds for PNI (odds ratio [OR], 0.47; 95% CI, 0.24-0.93; P = 0.031). Sex (OR, 0.85; P = 0.645) and operative time (OR, 1.07 per 30-minute increase; P = 0.263) were not associated with PNI. Most patients with PNI (97%) experienced complete or partial neurologic recovery at last documentation.

Conclusions: The incidence of PNI (2.2%) is consistent with previous estimates in patients undergoing TSA. The use of ISB did not increase the risk for PNI. Most patients with PNI had improvement of their neurologic symptoms. These results further support the use of ISB analgesia for patients undergoing TSA.