Patient Outcomes as a Function of Shoulder Surgeon Volume: A Systematic Review.

PURPOSE: To examine surgical complications, length of stay, surgical time, cost, revision rates, clinical outcomes, current surgical trends. and minimum number of cases in relationship to surgeon volume for shoulder arthroplasty and rotator cuff repair. METHODS: We performed a systematic review of studies using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All studies that met inclusion criteria from January 1990 to January 2016 were included. Inclusion criteria included Level IV evidence or greater, contained specific surgeon volume, and were written in or translated into English. Exclusion criteria included non-English manuscripts, abstracts, and review papers. A written protocol was used to extract relevant data and evaluate study results. Data extracted included volume-specific data pertaining to length of stay, operating time, complications, and cost. RESULTS: A total of 10 studies were included. Seven studies evaluated arthroplasty with 88,740 shoulders, and 3 studies evaluated rotator cuff repair with 63,535 shoulders. Variation was seen in how studies defined low- versus high-volume surgeon. For arthroplasty, <5 cases per year met the criteria for a low-volume surgeon and were associated with increased length of stay, longer operating room time, increased in-hospital complications, and increased cost. Mortality was not significantly increased. In rotator cuff surgery, <12 surgeries per year met the criteria for low volume and were associated with increased length of stay, increased operating room time, and increase in reoperation rate. CONCLUSIONS: Our systematic review demonstrates increased surgical complications, length of stay, surgical time, and surgical cost in shoulder arthroplasty and rotator cuff repair when performed by a low-volume shoulder surgeon, which is defined by those performing <5 arthroplasties and/or <12 rotator cuff repairs per year. LEVEL OF EVIDENCE: Level III, systematic review of Level II and III studies.

Phonation threshold pressure and flow in excised human larynges.

OBJECTIVES/HYPOTHESIS: To determine the phonation threshold pressure (PTP) and phonation threshold flow (PTF) in excised human larynges; determine the effects of posterior glottal width, glottal area, and gender on PTP and PTF; test the hypothesis that hysteresis is present in excised human laryngeal phonation; and compare these results to those from canine experiments and human subject measurements. STUDY DESIGN: Induced phonation of excised human larynges in the laboratory. METHODS: Nine human larynges were harvested within 24 hours postmortem. PTP and PTF at phonation onset and offset were measured on a bench apparatus. The effects of posterior glottal width, glottal area, and gender were examined. RESULTS: Large intersubject variability was observed in PTP and PTF. PTP was comparable to those measured in vivo, whereas PTF was substantially higher. One-way ANOVA showed no significant dependence of PTP and PTF on posterior glottal width. Hysteresis was observed, with offset PTP and PTF lower than onset values. Offset measurements had significantly less variability than onset measurements (P = .012 for PTP, P = .0001 for PTF). CONCLUSIONS: This study is one of the first to report onset and offset PTP and PTF in fresh excised human larynges. The high PTF observed likely reflects a large direct current flow component due to vocal fold bowing. Offset PTP and PTF values may be intrinsically more reliably measured than onset values. The large intersubject variability in PTP and PTF may have implication for the clinical application of these aerodynamic parameters of phonation.

Three-dimensional arytenoid movement induced by vocal fold injections.

OBJECTIVES/HYPOTHESIS: To quantitatively characterize arytenoid movement induced by vocal fold injection augmentation in an excised larynx model. STUDY DESIGN: : Laboratory and computational. METHODS: Vocal folds of human cadaveric larynges were injected with calcium hydroxylapatite. High-resolution computed tomography scans were obtained before and after injection. Densities corresponding to the arytenoid and cricoid cartilages were extracted and processed with custom MATLAB routines to generate selective three-dimensional reconstructions of the larynx. Pre- and postinjection positions of the arytenoid were compared. RESULTS: Vocal fold injections resulted in predominantly small-magnitude medial rotation and medial translation of the arytenoid. Movements in other directions as would be expected in physiologic adduction were not observed. CONCLUSIONS: Vocal fold injection augmentation induced passive movement of the arytenoid that has not been described previously. This movement does not reproduce the trajectory of physiologic adduction. This finding has implications for the treatment of unilateral vocal fold paralysis without arytenoid repositioning maneuvers.