title: Peripheral nerve blocks in shoulder arthroplasty: how do they influence complications and length of stay?
abstract: BACKGROUND
  Regional anesthesia has proven to be a highly effective technique for pain control after total shoulder arthroplasty. However, concerns have been raised about the safety of upper-extremity nerve blocks, particularly with respect to the incidence of perioperative respiratory and neurologic complications, and little is known about their influence, if any, on length of stay after surgery.
  
  
  OBJECTIVE
  Using a large national cohort, we asked: (1) How frequently are upper-extremity peripheral nerve blocks added to general anesthesia in patients undergoing total shoulder arthroplasty? (2) Are there differences in the incidence of and adjusted risk for major perioperative complications and mortality between patients receiving general anesthesia with and without nerve blocks? And (3) does resource utilization (blood product transfusion, intensive care unit admission, length of stay) differ between groups?
  
  
  METHODS
  We searched a nationwide discharge database for patients undergoing total shoulder arthroplasty under general anesthesia with or without addition of a nerve block. Groups were compared with regard to demographics, comorbidities, major perioperative complications, and length of stay. Multivariable logistic regressions were performed to measure complications and resource use. A negative binomial regression was fitted to measure length of stay.
  
  
  RESULTS
  We identified 17,157 patients who underwent total shoulder arthroplasty between 2007 and 2011. Of those, approximately 21% received an upper-extremity peripheral nerve block in addition to general anesthesia. Patients receiving combined regional-general anesthesia had similar mean age (68.6 years [95% CI: 68.2-68.9 years] versus 69.1 years [95% CI: 68.9-69.3 years], p < 0.0043), a slightly lower mean Deyo (comorbidity) index (0.87 versus 0.93, p = 0.0052), and similar prevalence of individual comorbidities, compared to those patients receiving general anesthesia only. Addition of regional anesthesia was not associated with different odds ratios for complications, transfusion, and intensive care unit admission. Incident rates for length of stay were also similar between groups (incident rate ratio = 0.99; 95% CI: 0.97-1.02; p = 0.467) CONCLUSIONS: Addition of regional to general anesthesia was not associated with an increased complication profile or increased use of resources. In combination with improved pain control as known from previous research, regional anesthesia may represent a viable management option for shoulder arthroplasty. However, further research is necessary to better clarify the risk of neurologic complications.
  
  
  METHODS
  Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Anesthesiology, Perioperative Medicine and Intensive Care, Paracelsus Medical University, Muellner Hauptstrasse 48, 5020, Salzburg, Austria, otto.stundner@gmail.com.
authors.forename: Ottokar
authors.initials: O
authors.lastname: Stundner
authors.forename: Rehana
authors.initials: R
authors.lastname: Rasul
authors.forename: Ya-Lin
authors.initials: YL
authors.lastname: Chiu
authors.forename: Xuming
authors.initials: X
authors.lastname: Sun
authors.forename: Madhu
authors.initials: M
authors.lastname: Mazumdar
authors.forename: Chad M
authors.initials: CM
authors.lastname: Brummett
authors.forename: Reinhold
authors.initials: R
authors.lastname: Ortmaier
authors.forename: Stavros G
authors.initials: SG
authors.lastname: Memtsoudis
mesh_terms: D000328:Adult; D000368:Aged; D000768:Anesthesia, General; D019643:Arthroplasty, Replacement / Q000009:adverse effects* / Q000401:mortality; D001803:Blood Transfusion; D016009:Chi-Square Distribution; D015897:Comorbidity; D003422:Critical Care; D005260:Female; D006801:Humans; D015994:Incidence; D007902:Length of Stay; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009407:Nerve Block / Q000009:adverse effects / Q000379:methods*; D016017:Odds Ratio; D011183:Postoperative Complications / Q000453:epidemiology / Q000401:mortality / Q000517:prevention & control*; D015995:Prevalence; D012189:Retrospective Studies; D012307:Risk Factors; D012785:Shoulder Joint / Q000294:innervation / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States / Q000453:epidemiology