LAUSR

The relationship between operative volume and patient outcomes after complex cardiovascular and oncologic operations has been well established; more recently, studies have sought to determine whether this relationship also exists for other operative procedures.1,2 High-volume surgeons have lesser rates of recurrent laryngeal nerve injury and hypoparathyroidism after thyroidectomy and parathyroidectomy, although the definition of a “high-volume surgeon” has varied, ranging from a minimum of 20–30 to >100 procedures.2,3 A recent study by Adam et al4 found that a threshold of 26 total thyroidectomies per year was associated with decreasing odds of a postoperative complication. Studies have also sought to determine the association between volume and outcomes in adrenal surgery, an operation that remains a vital component of the practice of a comprehensive endocrine surgeon’s practice.3,5 A difference, however, is that adrenalectomy remains a relatively uncommon operation and, although one might assume that as with other procedures, particularly with the advent of advanced laparoscopy and laparoscopic adrenalectomy, a relationship might exist between volume and outcomes, recent studies have had conflicting results. Stavrakis et al3 utilized discharge data from 2 states (New York and Florida) and found no association between operative volume and adrenal complications, although a greater operative volume was associated with less total costs and duration of hospital stay. In contrast, Park et al5 examined data from the Healthcare Cost and Utilization Project National (Nationwide) Inpatient Sample (HCUP-NIS) and found that lowvolume surgeons (defined as surgeons of any specialty who performed <4 adrenalectomies per year) had a greater rate of inpatient complications and a greater duration of hospital stay than high-volume adrenal surgeons. In this study, because surgeon specialty is not defined in HCUP-NIS, surgeons were grouped as urologists (those who performed ≥1 urologic procedure per year) or general surgeons (all other surgeons in the analysis); after multivariate analyses adjusting for patient and provider characteristics, however, only surgeon volume and not surgeon specialty was an independent predictor of complications and duration of hospital stay.5 In this month’s issue of Surgery, 2 studies have again broached the topic of surgeon volume and outcomes for adrenalectomy. In the first, Lindeman et al6 assessed surgeon specialty, volume, and patient demographics in 6,054 adrenalectomies identified utilizing the New York Statewide Planning and Research Cooperative System (SPARCS) from 2000–2014. SPARCS captures all adrenalectomies performed in New York state and contains specific individual surgeon identifiers, which allowed for specialty designation (urology, general surgery, endocrine surgery) in the analysis. Based on the previously discussed manuscript by Park et al, performance of ≥4 adrenalectomies per year defined a high-volume surgeon in the analysis. Over the 15 years of analyzed data, the median annual surgeon volume was 1 adrenalectomy (interquartile range [IQR], 1–2), with endocrine surgeons having a greater median volume per year (5, IQR, 6–18) as compared with urology (1, IQR, 1–5) and general surgery (1, IQR, 1–4; P < .001). On unadjusted analysis, complications and mortality were more common among urologists and general surgeons than among endocrine surgeons, but after multivariable logistic regression analyses, only surgeon volume and not specialty proved to be an independent predictor of complications, duration of hospital stay, and mortality.6 In the Lindeman et al6 study, however, the threshold of ≥4 adrenalectomies to define a high-volume surgeon was based on the findings of the study by Park et al,5 which utilized the highest quartile of surgeon volume in HCUP-NIS. In the second study in this month’s issue, Anderson et al7 sought to identify the optimal threshold for a high-volume adrenal surgeon with data from the HCUP-NIS from 1998–2009 (3,496 surgeons performed adrenalectomies in 6,712 patients). Like the Lindeman et al6 study, the median annual surgeon volume was 1 (range, 1–70); after adjustment for demographic, clinical, and hospital variables, the likelihood of a postoperative complication decreased with increasing surgeon volume up to an annual volume of 5.6 cases (95% confidence interval, 3.27–5.96). When outcomes were then analyzed by surgeon volume, 83% of patients had an adrenalectomy performed by a low-volume surgeon; these patients had a 36% increase in the odds of having a complication if the surgeon performed 1 adrenalectomy per year, 24% for 2 per year, 15% for 3 per year, 8% for 4 per year, and 3% for 5 per year.7 * Reprint requests: Tracy S. Wang, MD, MPH, Medical College of Wisconsin, 9200 W. Wisconsin Avenue, Milwaukee, WI 53226. E-mail: [email protected].