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Surgeon Volume and Outcomes in Benign Hysterectomy
Review Article
Surgeon Volume and Outcomes in Benign Hysterectomy Kemi M. Doll, MD, Magdy P. Milad, MD, MS, and Dana R. Gossett, MD, MSCI* From the Division of Gynecologic Oncology, University of North Carolina, Chapel Hill, North Carolina (Dr. Doll), and the Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, Illinois (Drs. Milad and Gossett).
ABSTRACT Annual surgeon case volume has been linked to patient outcome in a variety of surgical fields, although limited data focus on gynecologic surgery performed by general gynecologists. Herein we review the literature addressing the associations between intraoperative injury, postoperative morbidity, and resource use among surgeons performing a low vs high volume of hysterectomies. Although study design and populations differ, individual and composite morbidity outcomes consistently favored high-volume surgeons. Given the growing emphasis on competency-based evaluation in surgery, gynecology departments may soon consider volume requirements a component of privileging. Journal of Minimally Invasive Gynecology (2013) 20, 554–561 Ó 2013 AAGL. All rights reserved. Keywords:
DISCUSS
Hysterectomy; Operative outcomes; Surgeon volume
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Annual surgeon case volume has been linked to patient outcomes in a variety of surgical fields. Annual surgical volume of procedures such as abdominal aortic aneurysm repair, esophageal cancer resection, colon cancer surgery, and orthopedic procedures have demonstrated significant associations with operative morbidity and overall mortality [1]. Recently, surgeon volume requirements have been incorporated into maintenance of certification for cardiothoracic surgery [2]. Surgeon and hospital volume have also been incorporated into procedure-specific facility certification, as exemplified by the Centers of Excellence program for bariatric surgery. Ultimately, this designation has also been tied to Medicare and Medicaid reimbursement [3]. Inasmuch as hysterectomy is one of the most common surgical procedures performed in the United States, such a trend in emphasis on surgeon volume could have important repercussions for the general gynecologic surgeon. In older literature, The authors have no commercial, proprietary, or financial interest in the products or companies described in this article. Corresponding author: Dana R. Gossett, MD, MSCI, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, 680 N. Lake Shore Dr., Ste. 1015, Chicago, IL 60611. E-mail: [email protected] Submitted September 27, 2012. Accepted for publication March 16, 2013. Available at www.sciencedirect.com and www.jmig.org 1553-4650/$ - see front matter Ó 2013 AAGL. All rights reserved. http://dx.doi.org/10.1016/j.jmig.2013.03.005
Arndt et al [4] published a public health study that examined the relationship between surgeon volume and hospital resource use at 42 hospitals in Pennsylvania. They examined cholecystectomy, prostatectomy, intervertebral disc surgery, and hysterectomy. For hysterectomy, no relationship was found between surgeon volume and hospital charges or length of stay (LOS) [4]. In 2001, a study reporting on the incidence of ureteral injury in hysterectomy retrospectively examined 10 110 such procedures performed in Finland. A significantly decreased rate of bladder (0.8%) and ureteral (0.5%) injury was reported for surgeons performing .30 procedures per year, compared with those with lower volume (2.2% and 2.0%, respectively) [5]. A recent prospective study by Twijnstra et al [6] of predictors of surgical success for laparoscopic hysterectomy included a surgeon volume analysis. A significant favorable effect of surgeon experience (number of hysterectomies performed before the study period) on blood loss and adverse events was found [6]. The objective of the present review was to summarize the available literature about surgeon volume and patient outcomes in performance of benign hysterectomy by general gynecologic surgeons. The most common intraoperative and postoperative complications of benign hysterectomy and standard resource use parameters are presented. We hypothesize that, similar to other fields, annual surgeon case volume is associated with outcome measures.
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Surgeon Volume and Outcomes in Benign Hysterectomy
Literature Search and Article Selection Literature searches were conducted by the primary investigator (K.M.D.) and a professional health sciences research librarian. MEDLINE and Embase databases were searched for articles pertaining to annual surgeon case volume and hysterectomy. Using all dates available, indexed search terms pertaining to this topic were searched systematically. The first search was performed on December 1, 2011, and the last on August 11, 2012. The following details the search method for the MEDLINE database, using the PubMed search engine. The search terms (surgeon) AND ‘‘high volume’’ OR ‘‘low volume,’’ AND hysterectomy were searched. These results were combined individually with the following indexed terms using the boolean additive AND: treatment outcomes; intraoperative complications; clinical competence. (Surgeon) AND hysterectomy AND ‘‘morbidity’’ was then searched, and combined with postoperative complications and with intraoperative complications individually. Using indexed MeSH terms from the articles retrieved from these searches, the following individual searches were conducted: (‘‘surgical volume’’) AND hysterectomy and ([‘‘surgeon volume’’] AND gynecologic surgical procedures) AND intraoperative complications. All search results were combined. Table 1 gives the step-by-step search approach. With duplicates removed, 62 unique citations were identified. Similar searches were conducted in Embase (search engine Embase v6/2011). Efforts were made to include all studies. Reference lists of applicable articles were reviewed for any publications not identified in the search. Non– English language studies and abstracts were included, and their titles were translated by the search engines. Meeting
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abstracts were included in the Embase search. One additional citation was discovered in these databases that had not been previously found in MEDLINE. Re-inquiry in MEDLINE demonstrated that this study was recent and had not yet been indexed. Another additional study was found in reviewing the reference list of identified articles. Of the 64 articles identified, titles and abstracts were reviewed for inclusion by the primary investigator. Fifty-four studies were excluded for the following reasons: surgery for malignant indications, non-hysterectomy procedure, no case-volume analysis, and not an actual study (e.g., case report). Exclusions are detailed in Figure 1. We identified five articles that focused primarily on surgeon volume as related to outcomes for abdominal hysterectomy (AH), laparoscopic hysterectomy (LH), and vaginal hysterectomy (VH). Two additional articles featured a volume-outcome analysis as part of a larger study, mentioned in the introduction above. Study Methods All studies identified were retrospective reviews of surgical databases. Table 2 gives the design of the five primary studies [7–11]. The following section highlights important differences between the study designs that may affect interpretation of their results. For further details of each study’s methods, see the primary articles. Rogo-Gupta et al [8] and Wallenstein et al [11] used a multi-institutional, fee-supported national database. Boyd et al [10] used a multi-institutional, statewide database, and the results by Handstede et al [9] and Tunitsky et al [7] were based on single-institution reviews. For four of the studies, unadjusted and adjusted data were compiled
Table 1 MEDLINE search Search
Add to builder
Query
17 16
Add Add
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Add Add Add Add Add Add Add Add Add Add Add Add Add Add Add
Search (#15) OR #16 Search ((‘‘surgeon volume’’) AND gynecologic surgical procedures) AND intraoperative complications Search (#13) OR #14 Search (‘‘surgical volume’’) AND hysterectomy Search (#12) OR #2 Search (#10) OR #11 Search (#9) AND postoperative complications Search (#9) AND intraoperative complications Search ((surgeon) AND hysterectomy) AND ‘‘morbidity’’ Search (#2) AND #7 Search clinical competence Search (#2) AND #5 Search intraoperative complications Search (#2) AND #3 Search treatment outcomes Search (#1) AND hysterectomy Search (surgeon) AND ‘‘high volume’’ OR ‘‘low volume’’
No. of items found 62 4 61 13 55 38 36 17 67 2 64 615 7 60 369 7 745 858 22 3766
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Fig. 1 Search results and article exclusions.
and presented. To summarize, Rogo-Gupta, Boyd, and Wallenstein and their colleagues used large multi-institutional databases and reported results adjusted for age, comorbidity index, and insurance status. Rogo-Gupta and Wallenstein and their colleagues further accounted for urban-rural setting, race/ethnicity, teaching hospital, performance of secondary procedures, and indication for surgery. Boyd and colleagues further controlled for route of hysterectomy. Hanstede and colleagues controlled for age, race/ethnicity, route of hysterectomy, indication for surgery, and surgeon training. Although oncologists were included in the present study, the generalist-only data were also analyzed, and only those subgroups are presented herein. Tunitsky and colleagues evaluated common confounders in each group and found no significant differences for which to control. The definitions of low and high volume differed among studies. Tunitsky et al [7] noted that initially an annual case number of 40 was chosen because of its optimal receiver operator characteristics curve; however, only one surgeon met this high-volume definition, and thus a cutoff of 30 cases per year was used. In the studies by Rogo-Gupta et al [8] and Wallenstein et al [11], a three-tier volume definition of low, intermediate, and high was used. The case volume delineation was generated from the distribution of case volume from their data set and chosen to create equal data
groups. In the studies by Hanstede et al [9] and Boyd et al [10], the cutoff between high and low volume was made at the discretion of the authors and set at 10 cases in each study. The range of annual case volume was reported in two of the studies. Handstede and colleagues reported a range of 1 to 1135 cases over 11 years, yielding an annual case range of 1 to 103 cases per year. Boyd and colleagues reported a range of annual case volume from 1 to 106 cases per year. This information was not given in the other studies. Overview of Surgical Volume Data Intraoperative Injury An overview of intraoperative injury data is given in Table 3. Three studies evaluated intraoperative injury as a composite outcome, with both results favoring highvolume surgeons. In Hanstede et al [9], the unadjusted injury rate for AH was 5% vs 1.6%, with an adjusted odds ratio (OR) of 0.31 (95% confidence interval [CI], 0.15–0.65). Rogo-Gupta et al [8], evaluating VH, reported a 2.5% vs 1.7% unadjusted rate, with an adjusted OR of 0.69 (95% CI, 0.59–0.80). Wallenstein et al [11] found a 2.6% vs 1.9% unadjusted rate, with an adjusted OR of 0.85 (95% CI, 0.74–0.96). All composite outcomes combined genitourinary, intestinal, and vascular injuries.
Surgeon Volume and Outcomes in Benign Hysterectomy
Urinary Tract Injury Four studies reported on bladder and ureteral injuries. Two studies found no significant relationship with surgeon volume. In one study [9], there was a 1.8% vs 1.8% unadjusted urinary tract injury rate for AH, with an adjusted OR of 0.43 (95% CI, 0.11–1.74). Another study [7] reported a urologic injury rate of 1.2% vs 1.3%, with p . .99 in an LH group. Two studies did report differences. Wallenstein et al [11] reported a higher rate of ureteral (0.3% vs 0.1%; p , .001) and bladder (1.3% vs 1.0%; p , .001) injury for low-volume surgeons performing LH. Boyd et al [10], combining LH, VH, and AH, found a relationship between surgeon volume and ureteral injury, with 0.14% in the lowvolume surgeon group and 0.09% in the high-volume surgeon group (p 5 .005). The same study did not show a relationship between bladder injury and surgeon volume (0.79% vs 0.78%; p 5 .847).
National database
Intestinal Injury Two studies reported a significant association between surgeon volume and bowel injury. In AH, Hanstede et al [9] found similar bowel injury rates, 1.6% vs 1.6%, but with a significant adjusted OR of 0.14 (95% CI, 0.04– 0.53). For AH, LH, and VH, Boyd et al [10] also found similar rates, 1.83% (LV) vs 1.61% (HV), with a significant difference for surgeon volume (p 5 .004). For LH alone, Wallenstein et al [11] found no significant difference (0.2% vs 0.2%; p 5 .44) between low- and high-volume surgeons. Of note, in the smallest study (n 5 1016 patients), there were no reported bowel injuries among either low- or high-volume surgeons [7].
a
Benign disease identified by excluding ICD-9 codes for malignancy and obstetric indications.
Low: ,5.9 Medium: 5.9–14.0 High: R14.1 Laparoscopic 124 615 7925 Wallenstein [11], 2012
2000–2010
1016 48 Tunitsky et al [7], 2010
1999–2008
Abdominal, vaginal, and laparoscopic Laparoscopic 146 494 4511 2001–2006 Boyd et al [10], 2010
77 000 6195 2003–2007 Rogo-Gupta et al [8], 2010
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Endometriosis, hyperplasia, leiomyomas, menorrhagia/bleeding, ovarian/adnexal mass, pelvic organ prolapse, pelvic pain Endometriosis, leiomyomas, menorrhagia/ bleeding, ovarian/adnexal mass, pelvic organ prolapse
National database
Low: ,5.4 Medium: 5.5–13 High: .13 Low: ,10 High: R10 Low: ,30 High: R30 Vaginal
Single site
Leiomyomas, menorrhagia/bleeding, ovarian/adnexal mass, pelvic organ prolapse, pelvic pain Endometriosis, leiomyomas, menorrhagia/ bleeding, ovarian/adnexal mass, pelvic organ prolapse Benign diseasea Single site Low: ,10 High: R10
Statewide database
Indications for hysterectomy Data set Volume
Abdominal 7166 214 Hanstede et al [9], 2009
1995–2005
No. of procedures No. of surgeons Study date Study
Overview of studies addressing surgeon volume and hysterectomy outcomes
Table 2
Type of hysterectomy
Doll et al.
Vascular Injury Major vessel injury was reported as an individual outcome in two studies [9,11]. It was not significantly associated with surgeon volume in either study, with a rate of 1.5% for both low-volume (n 5 37) and high-volume (n 5 6) surgeons (OR, 0.59; 95% CI, 0.30–1.19) reported by Hanstede et al [9] and 0.01% reported by Wallenstein et al [11] for both low- and high-volume surgeons (p 5 .91). Table 3 Intraoperative morbidity as associated with high-volume surgeons Site of injury Study
Urinary tract
Intestine
Vascular
Composite
Hanstede et al [9] Rogo-Gupta et al [8] Boyd et al [10] Tunitsky et al [7] Wallenstein et al [11]
NA NP/NR [ NA [
[ NP/NR [ NAa NA
[ NP/NR NP/NR NP/NR NA
[ [ [ NP/NR [
NA 5 no association found; NP/NR 5 analysis not performed or not reported; [ 5 favors high-volume surgeons. a No occurrence of bowel injury was reported in either group.
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Table 4 Postoperative morbidity as associated with surgeon volume Morbidity Study
Transfusion Fever
Ileus
Hanstede et al [9] Rogo-Gupta et al [8] Boyd et al [10] Tunitsky et al [7] Wallenstein et al [11]
[ [
[ [ NA [ NP/NR NP/NR NP/NR [
[ NA [
[ NA NA
[ NA [
VTE
Composite
[ [ NP/NR NP/NR NA [
NA 5 no association found; NP/NR 5 analysis not performed or not reported; VTE 5 venous thromboembolism; [ 5 favors high-volume surgeons.
Postoperative Complications An overview of postoperative complications is given in Table 4. There was heterogeneity among studies insofar as how postoperative complications were defined and assessed. Rogo-Gupta et al [8] reported a composite postoperative outcome for VH (repeated operation, venous thromboembolism [VTE], and wound complications) of 5% vs 4.2% vs 4.0% for low-, intermediate-, and high-volume surgeons (OR, 0.81; 95% CI, 0.72–0.92; p , .001). They separately reported a medical complication composite, defined as cardiovascular, infectious, renal, gastrointestinal, and pulmonary complications, of 5.7% vs 4.7% vs 3.9% (OR, 0.76; 95% CI, 0.67–0.86; p , .001) [8]. Wallenstein et al [11] followed a similar format with a composite surgical site complication outcome (wound, abscess, hemorrhage, bowel obstruction, and ileus) of 2.7% vs 2.1% vs 1.8% (p , .001) for low-, intermediate-, and high-volume surgeons (OR, 0.70; 95% CI, 0.60–0.82). They also separately reported a composite medical complication rate (VTE, cardiopulmonary arrest, respiratory failure, renal failure, stroke, bacteremia or sepsis, shock, and pneumonia) of 1.6% vs 1.2% vs 0.9% (p , .001) for low-, intermediate-, and high-volume surgeons (OR, 0.63; 95% CI, 0.53–0.76) [11]. Hanstede et al [9] reported a composite postoperative outcome (fever, VTE, pulmonary embolism, myocardial infarction, paralytic ileus, and hemorrhage) of 11.6 vs 5.4% for low- vs high-volume surgeons (OR, 0.47; 95% CI, 0.32–0.69). Blood Transfusion All hysterectomy studies evaluated blood transfusion, with four of the five studies finding a significant relationship between surgeon volume and transfusion rate. For AH in a single institution there was a transfusion rate of 14.7% vs 10.4% (OR 0.50; 95% CI, 0.31–0.80) for low-volume and high-volume surgeons, respectively [9]. For VH, the rate was 2.2% vs 1.6% (OR, 0.72; 95% CI, 0.61–0.85) across a national database [8]. In the same national database, for LH, the rate was 1.8% vs 1.1% (OR, 0.75; 95% CI,
0.61–0.93) [11]. In a statewide database including LH, VH, and AH, the rate was 8.49 vs 5.6% among low- vs high-volume surgeons (p , .001) [10]. For LH alone, Tunistky et al [7] reported no significant difference, 3.0% vs 1.7% (p 5 .175), related to surgeon volume. Fever Of four studies that reported on febrile morbidity, two found a surgeon volume association. For AH, Hanstede et al [9] found a rate of 8.1% vs 36% (OR, 0.47; 95% CI, 0.34–0.65) among low- vs high-volume surgeons. For combined LH, AH, and VH, Boyd et al [10] reported a rate of 3.44% vs 2.11% (p , .001). In the two studies that compared only LH, Tunistky [7] found no significant difference, 2.4% vs 1.7% (p 5 .515), and Wallenstein et al [11], who reported only bacteremia and/or sepsis, found a difference of 0.1% vs 0.02% (p 5 .05). Ileus Four studies reported on postoperative ileus. For AH, Hanstede et al [9] found no difference, with 2.2% vs 1.5% (OR, 0.63; 95% CI, 0.20–1.96), among low- vs highvolume surgeons. For combined LH, AH, and VH, Boyd et al [10] reported 1.79% vs 1.4% (p , .001). For LH, the outcomes differed, with no difference, 0.6% vs 0.6% (p . .99) in one study [10] and a significant difference, 0.8% vs 0.5% (p , .001) in another [11]. Venous Thromboembolism Three studies reported on VTE. Hanstede et al [9] found no significant difference, 0.2% vs 0.2% (OR, 1.72; 95% CI, 0.55–5.35), for AH at a single institution. Wallenstein et al [11] reported no difference for LH, 0.1% vs 0.1% (p 5 .30). Boyd et al [10, examining AH, VH, and LH in a statewide database, found a significant difference in VTE rates of 0.23% vs 0.14% (p , .001). Mortality Mortality outcomes were reported in three studies. RogoGupta et al [8], when examining VH outcomes in a national database, found no difference in mortality (0.01% vs 0.01%; p 5 .56) for low- vs high-volume surgeons. The same was true for LH outcomes with similar death rates (0.01% vs 0.01%; p 5 .78) in both surgeon volume groups [11]. In contrast, Boyd et al [10], analyzing AH, LH, and VH from a statewide database, found a significant difference (0.21% vs 0.06%; p , .001) for low- vs high-volume surgeons. Resource Utilization Operative Time Three studies [7–9] addressed surgeon volume and operating time. All found a significantly shorter operating time among high-volume surgeons. The degree of difference was –16.9 minutes (95% CI, 235.12 to 21.27 minutes) for
Doll et al.
Surgeon Volume and Outcomes in Benign Hysterectomy
AH, 26.95 minutes (95% CI, 28.3 to 25.5 minutes) for VH, and for LH, 188 minutes (673.7 minutes) vs 163 minutes (659 minutes) for low- vs high-volume surgeons (p , .001) [7,8]. Readmission Three studies addressed readmission rate and surgeon volume. For AH, readmission was not significantly associated with surgeon volume (3.3% vs 2.2%; OR, 0.86; 95% CI, 0.44–1.69) [9]. For VH, readmission rates were higher in the high-volume surgeon group (1.4% vs 1.1%; OR, 1.24; 95% CI, 1.04–1.47) [8]. There was no difference for LH (4.2% vs 3.8%; p 5 .824) [7]. Length of Stay Five studies examined LOS. Hanstede et al [9] reported a LOS of 2.92 vs 2.74 days for low- vs high-volume surgeons, with a difference of –0.15 days (95% CI, 20.52 to 0.22) for AH. For VH, LOS was 1.97 vs 1.67 days, with a difference of 20.24 days (95% CI, 20.21 to 0.25) [8]. Boyd et al [10] examined LOS in a multivariable regression model and found a –0.44 day difference between low- and highvolume surgeons (95% CI, 20.35 to 20.53). For LH, in the data by Wallenstein et al [11], LOS .2 days was reported as 9.6% vs 6.3% for low- vs high-volume surgeons (p , .001) [1]. In the study of LH by Tunistky et al [7], there was no difference in LOS based on surgeon volume. Cost Two studies evaluated surgeon volume as it relates to cost of care. Rogo-Gupta et al [8] examined the cost of VH as related to surgeon case volume. Cost of VH was $5246.79 for low-volume surgeons vs $4550.14 for high-volume surgeons. After adjustment for concomitant procedures and other confounders, they reported a $609 difference in cost, still favoring high-volume surgeons [8]. Wallenstein et al [11] performed a similar analysis and reported an average cost of $6390 for low-volume vs $5523 for high-volume surgeons (p , .001). They further estimated an annual nationwide savings of $71.5 million if all hysterectomies were performed by high-volume surgeons [11]. Commentary In gynecologic surgery there are relatively limited data that address the relationship between surgeon volume and perioperative outcomes. We review herein the largest studies addressing AH, VH, and LH outcomes and surgeon volume. The studies are heterogeneous in their design, ranging from single-institution retrospective reviews to multi-institutional national database analyses. They include wide-ranging hospital settings, from small private hospitals to large academic institutions, as well as urban and rural communities. Surgeon volume is also defined differently (Table 2). With these differences, as well as our consolidation of AH, LH, and VH, it is not surprising that some results are contradictory.
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One of the drawbacks of attempting to study the relationship of annual case volume with outcomes is the question of the cutoff threshold. It is presumed that the difference between surgeon outcomes for case volume loads that border the cutoff values would not be very different unless considered in a grouping, as the authors of each study have done. The problem of finding a cutoff is evidenced in the wide range among articles of how high volume was defined. Perhaps a better description is really ‘‘higher’’ volume or ‘‘not low’’ volume, addressing the fact that ‘‘high-volume’’ seems to have been defined in reference to the least productive surgeon group within each study. Despite this, all studies showed statistically significant differences in morbidity and/or resource use. This implies that there may be more a dose-response relationship with annual volume and outcomes than a strict cutoff. This is further supported by the design of the studies by Rogo-Gupta et al [8] and Wallenstein et al [11], who used a graduated definition of volume and found significant, albeit small, differences at each level. Hanstede et al [9] reported that a cutoff of 10 cases was chosen on the basis of the distribution of annual case volume; however, when they applied a more stringent cutoff of 50 cases per year, their results were similar, although this analysis was not reported. We believe the robustness of the study by Tunitsky et al [7], with its comprehensive data on comorbidities and medical record correlation, provides a reasonable cutoff of 30 cases per year. In addition, the indication for surgery can confound the outcomes analysis. Each study is focused on benign indications, and four of five give details as to these conditions and control for them in the analysis (Table 2). Specifics such as stage of endometriosis or uterine size are not reported; thus, potential confounding could still be present. We imagine that high-volume surgeons would be more likely to perform operations with a higher level of technical difficulty. If this is the case, then complication risk and resource use would be balanced against their favor, yet theses studies consistently report better outcomes among these surgeons. The overall complication rate for benign hysterectomy is low. In the largest case series we found in published literature, the complication rate of 10 110 hysterectomies was evaluated according to approach [5]. The data were gathered from 58 hospitals and .100 surgeons in 1996 in Finland. Of reported injuries, 0.2% were ureteral, 0.5% were bladder, and 0.2% were bowel. Postoperative complication rates were 3.1% for wound infection, 0.1% for intraabdominal infection, 4.2% for urinary tract infection, 2.1% for intraabdominal hemorrhage, 0.3% for vaginal cuff hemorrhage, 0.2% for thromboembolism, and 0.02% for death. We report all of the statistically significant findings given by the five surgeon volume studies. Taken individually, some of these results are small numerical differences that may not seem clinically relevant. However, the composite intraoperative and postoperative morbidity analysis consistently favored high-volume surgeons. Inasmuch as benign hysterectomy is still one of the most common surgical procedures
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performed in the United State, these aggregate results are of importance to patient outcomes. The individual type of complication differed with respect to urogenital, intestinal, or vascular injury among the studies and across the types of hysterectomy; however, all three studies that assessed a composite intraoperative injury rate favored high-volume surgeons. The same can be said for postoperative complications, with composite outcomes and selected individual outcomes favoring high-volume surgeons. The largest study, conducted by Boyd et al [10], which included .140 000 procedures performed by .4500 surgeons, found significantly increased mortality among low-volume surgeons. There was an overall 36% increased incidence of total acute morbidity for low-volume surgeons compared with their high-volume colleagues [10]. Because health care costs have an increasingly critical role in our system, perhaps the more compelling results to discuss are the differences found in resource use among the surgeon groups. Although differences in operative time and LOS were again small in absolute terms, e.g., a 0.44-day difference in LOS found by Boyd et al [10], when considered together and multiplied across the thousands of hysterectomies performed each year, they add up. In addition to reporting an almost $1000 difference in cost between high-volume and low-volume surgeons, Wallenstein et al [11] further estimated a savings of $71.5 million if all laparoscopic hysterectomies were performed by highvolume surgeons. Surgeon volume is increasingly being used as a component in assessment of individual and hospital surgical quality [12]. Within gynecology, case volume is a suggested component of clinical privileging, and in other surgical fields it has become a required part of maintenance of certification [2,13]. In bariatric surgery, surgeon and hospital volume have even become linked with insurance reimbursement [3]. As noted, with the current literature on surgeon volume relationships in gynecology, there is significant heterogeneity of results among individual outcomes. One could thus argue that the data do not support reliance on volume as a true marker of surgeon competence. These data, however, are limited by the overall low complication rate in benign gynecologic procedures. We see no reason to expect that ultimately gynecologic surgery will be exempt from the relationships that have been demonstrated in other surgical fields, including gynecologic oncology [14]. Only a large-scale, multiple-year, prospective study would provide stronger evidence to support the effect of surgeon volume in gynecology, and is needed in future research. However, the active press for comprehensive competencybased hospital privileging and board certification may well advance in its absence. The topic of surgeon assessment and quality improvement is multifaceted. In his popular book Outliers, Gladwell [15] argues that 10 000 hours of deliberate practice is required for mastery of any skill. In his essay ‘‘Personal Best,’’ noted surgeon and author Atul Guwande [16] makes the case that even high-volume surgeons
can benefit from focused mentoring. An approach that incorporates both of these concepts could have an adjunctive role in both maintenance of certification and surgical quality improvement initiatives in gynecology departments. Peer review has become a virtually universal and crucial component of hospital credentialing and should be maintained. On the basis of data available both within and outside of gynecology, we believe that annual case volume requirements may also be a useful component of hospital-based surgical credentialing. To be most meaningful, these requirements could be case-specific. Failure to meet such requirements would trigger re-evaluation of specific competencies before renewal, without compromising gynecologists’ privilege to perform procedures with which they are more familiar. In the era of limited work hours for residents and limited patient referral networks for many academic and private attending surgeons, the case load required for 10 000 hours of repetition may not be feasible. The assumption that all new physicians, who will most likely begin as low-volume surgeons, will eventually have the patient roster to become high-volume surgeons may no longer be accurate for many graduating residents today. Wallenstein et al [11] highlight that the percentage of women treated by low-volume surgeons has only increased over 10 years. Boyd et al [10] reported that the range between their 25th and 75th percentiles was narrow at 1 and 8.9 cases per year, again supporting that a large percentage of surgeons perform ,30 procedures per year. This may well represent the larger generalist gynecologic community. The hybrid obstetriciangynecologist career can be uniquely vulnerable to volume requirements, which could ultimately limit major operative cases to select surgeons. We acknowledge that such limitations may not be popular to our audience. It may be that by designating a specific physician(s) as the primary surgeon(s) of a practice, the spirit of generalism and the desire to provide the broadest scope of obstetric-gynecologic care can be maintained within individual practices, if not for individual physicians. Hospital departments may soon be forced to consider incorporating case volume data in the surgical privileging process. There is a need for prospective high-quality data to inform these trends for the sake of improving patient outcomes and striving for the highest quality of care. References 1. Birkmeyer JD, Stukel TA, Siewers AE, et al. Surgeon volume and operative mortality in the United States. N Engl J Med. 2003;349: 2117–2127. 2. American Board of Thoracic Surgery. Certification: operative requirements. Available at www.abts.org/sections/certification/operative_ requirements/index.aspx. Accessed April 18 2012. 3. www.surgicalreview.org/coe-programs/overview. Surgical Review Corp.; 2012. Accessed online December 15, 2011. 4. Arndt M, Bradbury R, Golec J. Surgeon volume and hospital resource utilization. Inquiry. 1995;32:407–417. 5. Makinen J, Johansson J, Tomas C, et al. Morbidity of 10,110 hysterectomies by type of approach. Hum Reprod. 2001;16:1473–1478.
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Surgeon Volume and Outcomes in Benign Hysterectomy
6. Twijnstra AR, Blikkendall MD, von Zwet EW, van Kersteren PJ, de Kroon CD, Jansen FW. Predictors of successful surgical outcome in laparoscopic hysterectomy. Obstet Gynecol. 2012;119:700–708. 7. Tunitsky E, Citil A, Ayaz R, Esin S, Knee A, Harmanli O. Does surgical volume influence short-term outcomes of laparoscopic hysterectomy? Am J Obstet Gynecol. 2010;203:24–26. 8. Rogo-Gupta L, Lewin S, Kim JH, et al. The effect of surgeon volume on outcomes and resource use for vaginal hysterectomy. Obstet Gynecol. 2010;116:1341–1347. 9. Hanstede MM, Wise LA, Stewart EA, et al. The relation of annual surgeon case volume to clinical outcomes and resource utilization in abdominal hysterectomy. J Reprod Med. 2009;54:193–202. 10. Boyd L, Novetsky A, Curtin J. Effect of surgical volume on route of hysterectomy and short-term morbidity. Obstet Gynecol. 2010;116: 909–915.
561 11. Wallenstein M, Ananth C, Kim J, et al. Effect of surgical volume on outcomes for laparoscopic hysterectomy for benign indications. Obstet Gynecol. 2012;119:709–716. 12. Joint Commission Standard MS 4.30. Available at www.jointcommission. org/standards_information. Accessed September 15, 2012. 13. Quality and Safety in Women’s Health Care. 2nd ed. American College of Obstetricians and Gynecologists. Washington, DC; 2010. Available at www.acog.org/resources_and_publications. Accessed December 1, 2011. 14. Bristow RE, Zuharek ML, Diaz-Montes TP, et al. Impact of surgeon and hospital ovarian cancer surgical case volume on in-hospital mortality and related short-term outcomes. Gynecol Oncol. 2009;115:334–338. 15. Gladwell M. Outliers. New York, NY: Little, Brown & Co; 2008. 16. Guwande A. Personal best. The New Yorker; October 3, 2011. Accessed online December 1, 2011.
Surgeon Volume and Outcomes in Benign Hysterectomy Kemi M. Doll, MD, Magdy P. Milad, MD, MS, and Dana R. Gossett, MD, MSCI* From the Division of Gynecologic Oncology, University of North Carolina, Chapel Hill, North Carolina (Dr. Doll), and the Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, Chicago, Illinois (Drs. Milad and Gossett).
ABSTRACT Annual surgeon case volume has been linked to patient outcome in a variety of surgical fields, although limited data focus on gynecologic surgery performed by general gynecologists. Herein we review the literature addressing the associations between intraoperative injury, postoperative morbidity, and resource use among surgeons performing a low vs high volume of hysterectomies. Although study design and populations differ, individual and composite morbidity outcomes consistently favored high-volume surgeons. Given the growing emphasis on competency-based evaluation in surgery, gynecology departments may soon consider volume requirements a component of privileging. Journal of Minimally Invasive Gynecology (2013) 20, 554–561 Ó 2013 AAGL. All rights reserved. Keywords:
DISCUSS
Hysterectomy; Operative outcomes; Surgeon volume
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Annual surgeon case volume has been linked to patient outcomes in a variety of surgical fields. Annual surgical volume of procedures such as abdominal aortic aneurysm repair, esophageal cancer resection, colon cancer surgery, and orthopedic procedures have demonstrated significant associations with operative morbidity and overall mortality [1]. Recently, surgeon volume requirements have been incorporated into maintenance of certification for cardiothoracic surgery [2]. Surgeon and hospital volume have also been incorporated into procedure-specific facility certification, as exemplified by the Centers of Excellence program for bariatric surgery. Ultimately, this designation has also been tied to Medicare and Medicaid reimbursement [3]. Inasmuch as hysterectomy is one of the most common surgical procedures performed in the United States, such a trend in emphasis on surgeon volume could have important repercussions for the general gynecologic surgeon. In older literature, The authors have no commercial, proprietary, or financial interest in the products or companies described in this article. Corresponding author: Dana R. Gossett, MD, MSCI, Department of Obstetrics and Gynecology, Northwestern University Feinberg School of Medicine, 680 N. Lake Shore Dr., Ste. 1015, Chicago, IL 60611. E-mail: [email protected] Submitted September 27, 2012. Accepted for publication March 16, 2013. Available at www.sciencedirect.com and www.jmig.org 1553-4650/$ - see front matter Ó 2013 AAGL. All rights reserved. http://dx.doi.org/10.1016/j.jmig.2013.03.005
Arndt et al [4] published a public health study that examined the relationship between surgeon volume and hospital resource use at 42 hospitals in Pennsylvania. They examined cholecystectomy, prostatectomy, intervertebral disc surgery, and hysterectomy. For hysterectomy, no relationship was found between surgeon volume and hospital charges or length of stay (LOS) [4]. In 2001, a study reporting on the incidence of ureteral injury in hysterectomy retrospectively examined 10 110 such procedures performed in Finland. A significantly decreased rate of bladder (0.8%) and ureteral (0.5%) injury was reported for surgeons performing .30 procedures per year, compared with those with lower volume (2.2% and 2.0%, respectively) [5]. A recent prospective study by Twijnstra et al [6] of predictors of surgical success for laparoscopic hysterectomy included a surgeon volume analysis. A significant favorable effect of surgeon experience (number of hysterectomies performed before the study period) on blood loss and adverse events was found [6]. The objective of the present review was to summarize the available literature about surgeon volume and patient outcomes in performance of benign hysterectomy by general gynecologic surgeons. The most common intraoperative and postoperative complications of benign hysterectomy and standard resource use parameters are presented. We hypothesize that, similar to other fields, annual surgeon case volume is associated with outcome measures.
Doll et al.
Surgeon Volume and Outcomes in Benign Hysterectomy
Literature Search and Article Selection Literature searches were conducted by the primary investigator (K.M.D.) and a professional health sciences research librarian. MEDLINE and Embase databases were searched for articles pertaining to annual surgeon case volume and hysterectomy. Using all dates available, indexed search terms pertaining to this topic were searched systematically. The first search was performed on December 1, 2011, and the last on August 11, 2012. The following details the search method for the MEDLINE database, using the PubMed search engine. The search terms (surgeon) AND ‘‘high volume’’ OR ‘‘low volume,’’ AND hysterectomy were searched. These results were combined individually with the following indexed terms using the boolean additive AND: treatment outcomes; intraoperative complications; clinical competence. (Surgeon) AND hysterectomy AND ‘‘morbidity’’ was then searched, and combined with postoperative complications and with intraoperative complications individually. Using indexed MeSH terms from the articles retrieved from these searches, the following individual searches were conducted: (‘‘surgical volume’’) AND hysterectomy and ([‘‘surgeon volume’’] AND gynecologic surgical procedures) AND intraoperative complications. All search results were combined. Table 1 gives the step-by-step search approach. With duplicates removed, 62 unique citations were identified. Similar searches were conducted in Embase (search engine Embase v6/2011). Efforts were made to include all studies. Reference lists of applicable articles were reviewed for any publications not identified in the search. Non– English language studies and abstracts were included, and their titles were translated by the search engines. Meeting
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abstracts were included in the Embase search. One additional citation was discovered in these databases that had not been previously found in MEDLINE. Re-inquiry in MEDLINE demonstrated that this study was recent and had not yet been indexed. Another additional study was found in reviewing the reference list of identified articles. Of the 64 articles identified, titles and abstracts were reviewed for inclusion by the primary investigator. Fifty-four studies were excluded for the following reasons: surgery for malignant indications, non-hysterectomy procedure, no case-volume analysis, and not an actual study (e.g., case report). Exclusions are detailed in Figure 1. We identified five articles that focused primarily on surgeon volume as related to outcomes for abdominal hysterectomy (AH), laparoscopic hysterectomy (LH), and vaginal hysterectomy (VH). Two additional articles featured a volume-outcome analysis as part of a larger study, mentioned in the introduction above. Study Methods All studies identified were retrospective reviews of surgical databases. Table 2 gives the design of the five primary studies [7–11]. The following section highlights important differences between the study designs that may affect interpretation of their results. For further details of each study’s methods, see the primary articles. Rogo-Gupta et al [8] and Wallenstein et al [11] used a multi-institutional, fee-supported national database. Boyd et al [10] used a multi-institutional, statewide database, and the results by Handstede et al [9] and Tunitsky et al [7] were based on single-institution reviews. For four of the studies, unadjusted and adjusted data were compiled
Table 1 MEDLINE search Search
Add to builder
Query
17 16
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15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
Add Add Add Add Add Add Add Add Add Add Add Add Add Add Add
Search (#15) OR #16 Search ((‘‘surgeon volume’’) AND gynecologic surgical procedures) AND intraoperative complications Search (#13) OR #14 Search (‘‘surgical volume’’) AND hysterectomy Search (#12) OR #2 Search (#10) OR #11 Search (#9) AND postoperative complications Search (#9) AND intraoperative complications Search ((surgeon) AND hysterectomy) AND ‘‘morbidity’’ Search (#2) AND #7 Search clinical competence Search (#2) AND #5 Search intraoperative complications Search (#2) AND #3 Search treatment outcomes Search (#1) AND hysterectomy Search (surgeon) AND ‘‘high volume’’ OR ‘‘low volume’’
No. of items found 62 4 61 13 55 38 36 17 67 2 64 615 7 60 369 7 745 858 22 3766
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Fig. 1 Search results and article exclusions.
and presented. To summarize, Rogo-Gupta, Boyd, and Wallenstein and their colleagues used large multi-institutional databases and reported results adjusted for age, comorbidity index, and insurance status. Rogo-Gupta and Wallenstein and their colleagues further accounted for urban-rural setting, race/ethnicity, teaching hospital, performance of secondary procedures, and indication for surgery. Boyd and colleagues further controlled for route of hysterectomy. Hanstede and colleagues controlled for age, race/ethnicity, route of hysterectomy, indication for surgery, and surgeon training. Although oncologists were included in the present study, the generalist-only data were also analyzed, and only those subgroups are presented herein. Tunitsky and colleagues evaluated common confounders in each group and found no significant differences for which to control. The definitions of low and high volume differed among studies. Tunitsky et al [7] noted that initially an annual case number of 40 was chosen because of its optimal receiver operator characteristics curve; however, only one surgeon met this high-volume definition, and thus a cutoff of 30 cases per year was used. In the studies by Rogo-Gupta et al [8] and Wallenstein et al [11], a three-tier volume definition of low, intermediate, and high was used. The case volume delineation was generated from the distribution of case volume from their data set and chosen to create equal data
groups. In the studies by Hanstede et al [9] and Boyd et al [10], the cutoff between high and low volume was made at the discretion of the authors and set at 10 cases in each study. The range of annual case volume was reported in two of the studies. Handstede and colleagues reported a range of 1 to 1135 cases over 11 years, yielding an annual case range of 1 to 103 cases per year. Boyd and colleagues reported a range of annual case volume from 1 to 106 cases per year. This information was not given in the other studies. Overview of Surgical Volume Data Intraoperative Injury An overview of intraoperative injury data is given in Table 3. Three studies evaluated intraoperative injury as a composite outcome, with both results favoring highvolume surgeons. In Hanstede et al [9], the unadjusted injury rate for AH was 5% vs 1.6%, with an adjusted odds ratio (OR) of 0.31 (95% confidence interval [CI], 0.15–0.65). Rogo-Gupta et al [8], evaluating VH, reported a 2.5% vs 1.7% unadjusted rate, with an adjusted OR of 0.69 (95% CI, 0.59–0.80). Wallenstein et al [11] found a 2.6% vs 1.9% unadjusted rate, with an adjusted OR of 0.85 (95% CI, 0.74–0.96). All composite outcomes combined genitourinary, intestinal, and vascular injuries.
Surgeon Volume and Outcomes in Benign Hysterectomy
Urinary Tract Injury Four studies reported on bladder and ureteral injuries. Two studies found no significant relationship with surgeon volume. In one study [9], there was a 1.8% vs 1.8% unadjusted urinary tract injury rate for AH, with an adjusted OR of 0.43 (95% CI, 0.11–1.74). Another study [7] reported a urologic injury rate of 1.2% vs 1.3%, with p . .99 in an LH group. Two studies did report differences. Wallenstein et al [11] reported a higher rate of ureteral (0.3% vs 0.1%; p , .001) and bladder (1.3% vs 1.0%; p , .001) injury for low-volume surgeons performing LH. Boyd et al [10], combining LH, VH, and AH, found a relationship between surgeon volume and ureteral injury, with 0.14% in the lowvolume surgeon group and 0.09% in the high-volume surgeon group (p 5 .005). The same study did not show a relationship between bladder injury and surgeon volume (0.79% vs 0.78%; p 5 .847).
National database
Intestinal Injury Two studies reported a significant association between surgeon volume and bowel injury. In AH, Hanstede et al [9] found similar bowel injury rates, 1.6% vs 1.6%, but with a significant adjusted OR of 0.14 (95% CI, 0.04– 0.53). For AH, LH, and VH, Boyd et al [10] also found similar rates, 1.83% (LV) vs 1.61% (HV), with a significant difference for surgeon volume (p 5 .004). For LH alone, Wallenstein et al [11] found no significant difference (0.2% vs 0.2%; p 5 .44) between low- and high-volume surgeons. Of note, in the smallest study (n 5 1016 patients), there were no reported bowel injuries among either low- or high-volume surgeons [7].
a
Benign disease identified by excluding ICD-9 codes for malignancy and obstetric indications.
Low: ,5.9 Medium: 5.9–14.0 High: R14.1 Laparoscopic 124 615 7925 Wallenstein [11], 2012
2000–2010
1016 48 Tunitsky et al [7], 2010
1999–2008
Abdominal, vaginal, and laparoscopic Laparoscopic 146 494 4511 2001–2006 Boyd et al [10], 2010
77 000 6195 2003–2007 Rogo-Gupta et al [8], 2010
557
Endometriosis, hyperplasia, leiomyomas, menorrhagia/bleeding, ovarian/adnexal mass, pelvic organ prolapse, pelvic pain Endometriosis, leiomyomas, menorrhagia/ bleeding, ovarian/adnexal mass, pelvic organ prolapse
National database
Low: ,5.4 Medium: 5.5–13 High: .13 Low: ,10 High: R10 Low: ,30 High: R30 Vaginal
Single site
Leiomyomas, menorrhagia/bleeding, ovarian/adnexal mass, pelvic organ prolapse, pelvic pain Endometriosis, leiomyomas, menorrhagia/ bleeding, ovarian/adnexal mass, pelvic organ prolapse Benign diseasea Single site Low: ,10 High: R10
Statewide database
Indications for hysterectomy Data set Volume
Abdominal 7166 214 Hanstede et al [9], 2009
1995–2005
No. of procedures No. of surgeons Study date Study
Overview of studies addressing surgeon volume and hysterectomy outcomes
Table 2
Type of hysterectomy
Doll et al.
Vascular Injury Major vessel injury was reported as an individual outcome in two studies [9,11]. It was not significantly associated with surgeon volume in either study, with a rate of 1.5% for both low-volume (n 5 37) and high-volume (n 5 6) surgeons (OR, 0.59; 95% CI, 0.30–1.19) reported by Hanstede et al [9] and 0.01% reported by Wallenstein et al [11] for both low- and high-volume surgeons (p 5 .91). Table 3 Intraoperative morbidity as associated with high-volume surgeons Site of injury Study
Urinary tract
Intestine
Vascular
Composite
Hanstede et al [9] Rogo-Gupta et al [8] Boyd et al [10] Tunitsky et al [7] Wallenstein et al [11]
NA NP/NR [ NA [
[ NP/NR [ NAa NA
[ NP/NR NP/NR NP/NR NA
[ [ [ NP/NR [
NA 5 no association found; NP/NR 5 analysis not performed or not reported; [ 5 favors high-volume surgeons. a No occurrence of bowel injury was reported in either group.
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Table 4 Postoperative morbidity as associated with surgeon volume Morbidity Study
Transfusion Fever
Ileus
Hanstede et al [9] Rogo-Gupta et al [8] Boyd et al [10] Tunitsky et al [7] Wallenstein et al [11]
[ [
[ [ NA [ NP/NR NP/NR NP/NR [
[ NA [
[ NA NA
[ NA [
VTE
Composite
[ [ NP/NR NP/NR NA [
NA 5 no association found; NP/NR 5 analysis not performed or not reported; VTE 5 venous thromboembolism; [ 5 favors high-volume surgeons.
Postoperative Complications An overview of postoperative complications is given in Table 4. There was heterogeneity among studies insofar as how postoperative complications were defined and assessed. Rogo-Gupta et al [8] reported a composite postoperative outcome for VH (repeated operation, venous thromboembolism [VTE], and wound complications) of 5% vs 4.2% vs 4.0% for low-, intermediate-, and high-volume surgeons (OR, 0.81; 95% CI, 0.72–0.92; p , .001). They separately reported a medical complication composite, defined as cardiovascular, infectious, renal, gastrointestinal, and pulmonary complications, of 5.7% vs 4.7% vs 3.9% (OR, 0.76; 95% CI, 0.67–0.86; p , .001) [8]. Wallenstein et al [11] followed a similar format with a composite surgical site complication outcome (wound, abscess, hemorrhage, bowel obstruction, and ileus) of 2.7% vs 2.1% vs 1.8% (p , .001) for low-, intermediate-, and high-volume surgeons (OR, 0.70; 95% CI, 0.60–0.82). They also separately reported a composite medical complication rate (VTE, cardiopulmonary arrest, respiratory failure, renal failure, stroke, bacteremia or sepsis, shock, and pneumonia) of 1.6% vs 1.2% vs 0.9% (p , .001) for low-, intermediate-, and high-volume surgeons (OR, 0.63; 95% CI, 0.53–0.76) [11]. Hanstede et al [9] reported a composite postoperative outcome (fever, VTE, pulmonary embolism, myocardial infarction, paralytic ileus, and hemorrhage) of 11.6 vs 5.4% for low- vs high-volume surgeons (OR, 0.47; 95% CI, 0.32–0.69). Blood Transfusion All hysterectomy studies evaluated blood transfusion, with four of the five studies finding a significant relationship between surgeon volume and transfusion rate. For AH in a single institution there was a transfusion rate of 14.7% vs 10.4% (OR 0.50; 95% CI, 0.31–0.80) for low-volume and high-volume surgeons, respectively [9]. For VH, the rate was 2.2% vs 1.6% (OR, 0.72; 95% CI, 0.61–0.85) across a national database [8]. In the same national database, for LH, the rate was 1.8% vs 1.1% (OR, 0.75; 95% CI,
0.61–0.93) [11]. In a statewide database including LH, VH, and AH, the rate was 8.49 vs 5.6% among low- vs high-volume surgeons (p , .001) [10]. For LH alone, Tunistky et al [7] reported no significant difference, 3.0% vs 1.7% (p 5 .175), related to surgeon volume. Fever Of four studies that reported on febrile morbidity, two found a surgeon volume association. For AH, Hanstede et al [9] found a rate of 8.1% vs 36% (OR, 0.47; 95% CI, 0.34–0.65) among low- vs high-volume surgeons. For combined LH, AH, and VH, Boyd et al [10] reported a rate of 3.44% vs 2.11% (p , .001). In the two studies that compared only LH, Tunistky [7] found no significant difference, 2.4% vs 1.7% (p 5 .515), and Wallenstein et al [11], who reported only bacteremia and/or sepsis, found a difference of 0.1% vs 0.02% (p 5 .05). Ileus Four studies reported on postoperative ileus. For AH, Hanstede et al [9] found no difference, with 2.2% vs 1.5% (OR, 0.63; 95% CI, 0.20–1.96), among low- vs highvolume surgeons. For combined LH, AH, and VH, Boyd et al [10] reported 1.79% vs 1.4% (p , .001). For LH, the outcomes differed, with no difference, 0.6% vs 0.6% (p . .99) in one study [10] and a significant difference, 0.8% vs 0.5% (p , .001) in another [11]. Venous Thromboembolism Three studies reported on VTE. Hanstede et al [9] found no significant difference, 0.2% vs 0.2% (OR, 1.72; 95% CI, 0.55–5.35), for AH at a single institution. Wallenstein et al [11] reported no difference for LH, 0.1% vs 0.1% (p 5 .30). Boyd et al [10, examining AH, VH, and LH in a statewide database, found a significant difference in VTE rates of 0.23% vs 0.14% (p , .001). Mortality Mortality outcomes were reported in three studies. RogoGupta et al [8], when examining VH outcomes in a national database, found no difference in mortality (0.01% vs 0.01%; p 5 .56) for low- vs high-volume surgeons. The same was true for LH outcomes with similar death rates (0.01% vs 0.01%; p 5 .78) in both surgeon volume groups [11]. In contrast, Boyd et al [10], analyzing AH, LH, and VH from a statewide database, found a significant difference (0.21% vs 0.06%; p , .001) for low- vs high-volume surgeons. Resource Utilization Operative Time Three studies [7–9] addressed surgeon volume and operating time. All found a significantly shorter operating time among high-volume surgeons. The degree of difference was –16.9 minutes (95% CI, 235.12 to 21.27 minutes) for
Doll et al.
Surgeon Volume and Outcomes in Benign Hysterectomy
AH, 26.95 minutes (95% CI, 28.3 to 25.5 minutes) for VH, and for LH, 188 minutes (673.7 minutes) vs 163 minutes (659 minutes) for low- vs high-volume surgeons (p , .001) [7,8]. Readmission Three studies addressed readmission rate and surgeon volume. For AH, readmission was not significantly associated with surgeon volume (3.3% vs 2.2%; OR, 0.86; 95% CI, 0.44–1.69) [9]. For VH, readmission rates were higher in the high-volume surgeon group (1.4% vs 1.1%; OR, 1.24; 95% CI, 1.04–1.47) [8]. There was no difference for LH (4.2% vs 3.8%; p 5 .824) [7]. Length of Stay Five studies examined LOS. Hanstede et al [9] reported a LOS of 2.92 vs 2.74 days for low- vs high-volume surgeons, with a difference of –0.15 days (95% CI, 20.52 to 0.22) for AH. For VH, LOS was 1.97 vs 1.67 days, with a difference of 20.24 days (95% CI, 20.21 to 0.25) [8]. Boyd et al [10] examined LOS in a multivariable regression model and found a –0.44 day difference between low- and highvolume surgeons (95% CI, 20.35 to 20.53). For LH, in the data by Wallenstein et al [11], LOS .2 days was reported as 9.6% vs 6.3% for low- vs high-volume surgeons (p , .001) [1]. In the study of LH by Tunistky et al [7], there was no difference in LOS based on surgeon volume. Cost Two studies evaluated surgeon volume as it relates to cost of care. Rogo-Gupta et al [8] examined the cost of VH as related to surgeon case volume. Cost of VH was $5246.79 for low-volume surgeons vs $4550.14 for high-volume surgeons. After adjustment for concomitant procedures and other confounders, they reported a $609 difference in cost, still favoring high-volume surgeons [8]. Wallenstein et al [11] performed a similar analysis and reported an average cost of $6390 for low-volume vs $5523 for high-volume surgeons (p , .001). They further estimated an annual nationwide savings of $71.5 million if all hysterectomies were performed by high-volume surgeons [11]. Commentary In gynecologic surgery there are relatively limited data that address the relationship between surgeon volume and perioperative outcomes. We review herein the largest studies addressing AH, VH, and LH outcomes and surgeon volume. The studies are heterogeneous in their design, ranging from single-institution retrospective reviews to multi-institutional national database analyses. They include wide-ranging hospital settings, from small private hospitals to large academic institutions, as well as urban and rural communities. Surgeon volume is also defined differently (Table 2). With these differences, as well as our consolidation of AH, LH, and VH, it is not surprising that some results are contradictory.
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One of the drawbacks of attempting to study the relationship of annual case volume with outcomes is the question of the cutoff threshold. It is presumed that the difference between surgeon outcomes for case volume loads that border the cutoff values would not be very different unless considered in a grouping, as the authors of each study have done. The problem of finding a cutoff is evidenced in the wide range among articles of how high volume was defined. Perhaps a better description is really ‘‘higher’’ volume or ‘‘not low’’ volume, addressing the fact that ‘‘high-volume’’ seems to have been defined in reference to the least productive surgeon group within each study. Despite this, all studies showed statistically significant differences in morbidity and/or resource use. This implies that there may be more a dose-response relationship with annual volume and outcomes than a strict cutoff. This is further supported by the design of the studies by Rogo-Gupta et al [8] and Wallenstein et al [11], who used a graduated definition of volume and found significant, albeit small, differences at each level. Hanstede et al [9] reported that a cutoff of 10 cases was chosen on the basis of the distribution of annual case volume; however, when they applied a more stringent cutoff of 50 cases per year, their results were similar, although this analysis was not reported. We believe the robustness of the study by Tunitsky et al [7], with its comprehensive data on comorbidities and medical record correlation, provides a reasonable cutoff of 30 cases per year. In addition, the indication for surgery can confound the outcomes analysis. Each study is focused on benign indications, and four of five give details as to these conditions and control for them in the analysis (Table 2). Specifics such as stage of endometriosis or uterine size are not reported; thus, potential confounding could still be present. We imagine that high-volume surgeons would be more likely to perform operations with a higher level of technical difficulty. If this is the case, then complication risk and resource use would be balanced against their favor, yet theses studies consistently report better outcomes among these surgeons. The overall complication rate for benign hysterectomy is low. In the largest case series we found in published literature, the complication rate of 10 110 hysterectomies was evaluated according to approach [5]. The data were gathered from 58 hospitals and .100 surgeons in 1996 in Finland. Of reported injuries, 0.2% were ureteral, 0.5% were bladder, and 0.2% were bowel. Postoperative complication rates were 3.1% for wound infection, 0.1% for intraabdominal infection, 4.2% for urinary tract infection, 2.1% for intraabdominal hemorrhage, 0.3% for vaginal cuff hemorrhage, 0.2% for thromboembolism, and 0.02% for death. We report all of the statistically significant findings given by the five surgeon volume studies. Taken individually, some of these results are small numerical differences that may not seem clinically relevant. However, the composite intraoperative and postoperative morbidity analysis consistently favored high-volume surgeons. Inasmuch as benign hysterectomy is still one of the most common surgical procedures
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Journal of Minimally Invasive Gynecology, Vol 20, No 5, September/October 2013
performed in the United State, these aggregate results are of importance to patient outcomes. The individual type of complication differed with respect to urogenital, intestinal, or vascular injury among the studies and across the types of hysterectomy; however, all three studies that assessed a composite intraoperative injury rate favored high-volume surgeons. The same can be said for postoperative complications, with composite outcomes and selected individual outcomes favoring high-volume surgeons. The largest study, conducted by Boyd et al [10], which included .140 000 procedures performed by .4500 surgeons, found significantly increased mortality among low-volume surgeons. There was an overall 36% increased incidence of total acute morbidity for low-volume surgeons compared with their high-volume colleagues [10]. Because health care costs have an increasingly critical role in our system, perhaps the more compelling results to discuss are the differences found in resource use among the surgeon groups. Although differences in operative time and LOS were again small in absolute terms, e.g., a 0.44-day difference in LOS found by Boyd et al [10], when considered together and multiplied across the thousands of hysterectomies performed each year, they add up. In addition to reporting an almost $1000 difference in cost between high-volume and low-volume surgeons, Wallenstein et al [11] further estimated a savings of $71.5 million if all laparoscopic hysterectomies were performed by highvolume surgeons. Surgeon volume is increasingly being used as a component in assessment of individual and hospital surgical quality [12]. Within gynecology, case volume is a suggested component of clinical privileging, and in other surgical fields it has become a required part of maintenance of certification [2,13]. In bariatric surgery, surgeon and hospital volume have even become linked with insurance reimbursement [3]. As noted, with the current literature on surgeon volume relationships in gynecology, there is significant heterogeneity of results among individual outcomes. One could thus argue that the data do not support reliance on volume as a true marker of surgeon competence. These data, however, are limited by the overall low complication rate in benign gynecologic procedures. We see no reason to expect that ultimately gynecologic surgery will be exempt from the relationships that have been demonstrated in other surgical fields, including gynecologic oncology [14]. Only a large-scale, multiple-year, prospective study would provide stronger evidence to support the effect of surgeon volume in gynecology, and is needed in future research. However, the active press for comprehensive competencybased hospital privileging and board certification may well advance in its absence. The topic of surgeon assessment and quality improvement is multifaceted. In his popular book Outliers, Gladwell [15] argues that 10 000 hours of deliberate practice is required for mastery of any skill. In his essay ‘‘Personal Best,’’ noted surgeon and author Atul Guwande [16] makes the case that even high-volume surgeons
can benefit from focused mentoring. An approach that incorporates both of these concepts could have an adjunctive role in both maintenance of certification and surgical quality improvement initiatives in gynecology departments. Peer review has become a virtually universal and crucial component of hospital credentialing and should be maintained. On the basis of data available both within and outside of gynecology, we believe that annual case volume requirements may also be a useful component of hospital-based surgical credentialing. To be most meaningful, these requirements could be case-specific. Failure to meet such requirements would trigger re-evaluation of specific competencies before renewal, without compromising gynecologists’ privilege to perform procedures with which they are more familiar. In the era of limited work hours for residents and limited patient referral networks for many academic and private attending surgeons, the case load required for 10 000 hours of repetition may not be feasible. The assumption that all new physicians, who will most likely begin as low-volume surgeons, will eventually have the patient roster to become high-volume surgeons may no longer be accurate for many graduating residents today. Wallenstein et al [11] highlight that the percentage of women treated by low-volume surgeons has only increased over 10 years. Boyd et al [10] reported that the range between their 25th and 75th percentiles was narrow at 1 and 8.9 cases per year, again supporting that a large percentage of surgeons perform ,30 procedures per year. This may well represent the larger generalist gynecologic community. The hybrid obstetriciangynecologist career can be uniquely vulnerable to volume requirements, which could ultimately limit major operative cases to select surgeons. We acknowledge that such limitations may not be popular to our audience. It may be that by designating a specific physician(s) as the primary surgeon(s) of a practice, the spirit of generalism and the desire to provide the broadest scope of obstetric-gynecologic care can be maintained within individual practices, if not for individual physicians. Hospital departments may soon be forced to consider incorporating case volume data in the surgical privileging process. There is a need for prospective high-quality data to inform these trends for the sake of improving patient outcomes and striving for the highest quality of care. References 1. Birkmeyer JD, Stukel TA, Siewers AE, et al. Surgeon volume and operative mortality in the United States. N Engl J Med. 2003;349: 2117–2127. 2. American Board of Thoracic Surgery. Certification: operative requirements. Available at www.abts.org/sections/certification/operative_ requirements/index.aspx. Accessed April 18 2012. 3. www.surgicalreview.org/coe-programs/overview. Surgical Review Corp.; 2012. Accessed online December 15, 2011. 4. Arndt M, Bradbury R, Golec J. Surgeon volume and hospital resource utilization. Inquiry. 1995;32:407–417. 5. Makinen J, Johansson J, Tomas C, et al. Morbidity of 10,110 hysterectomies by type of approach. Hum Reprod. 2001;16:1473–1478.
Doll et al.
Surgeon Volume and Outcomes in Benign Hysterectomy
6. Twijnstra AR, Blikkendall MD, von Zwet EW, van Kersteren PJ, de Kroon CD, Jansen FW. Predictors of successful surgical outcome in laparoscopic hysterectomy. Obstet Gynecol. 2012;119:700–708. 7. Tunitsky E, Citil A, Ayaz R, Esin S, Knee A, Harmanli O. Does surgical volume influence short-term outcomes of laparoscopic hysterectomy? Am J Obstet Gynecol. 2010;203:24–26. 8. Rogo-Gupta L, Lewin S, Kim JH, et al. The effect of surgeon volume on outcomes and resource use for vaginal hysterectomy. Obstet Gynecol. 2010;116:1341–1347. 9. Hanstede MM, Wise LA, Stewart EA, et al. The relation of annual surgeon case volume to clinical outcomes and resource utilization in abdominal hysterectomy. J Reprod Med. 2009;54:193–202. 10. Boyd L, Novetsky A, Curtin J. Effect of surgical volume on route of hysterectomy and short-term morbidity. Obstet Gynecol. 2010;116: 909–915.
561 11. Wallenstein M, Ananth C, Kim J, et al. Effect of surgical volume on outcomes for laparoscopic hysterectomy for benign indications. Obstet Gynecol. 2012;119:709–716. 12. Joint Commission Standard MS 4.30. Available at www.jointcommission. org/standards_information. Accessed September 15, 2012. 13. Quality and Safety in Women’s Health Care. 2nd ed. American College of Obstetricians and Gynecologists. Washington, DC; 2010. Available at www.acog.org/resources_and_publications. Accessed December 1, 2011. 14. Bristow RE, Zuharek ML, Diaz-Montes TP, et al. Impact of surgeon and hospital ovarian cancer surgical case volume on in-hospital mortality and related short-term outcomes. Gynecol Oncol. 2009;115:334–338. 15. Gladwell M. Outliers. New York, NY: Little, Brown & Co; 2008. 16. Guwande A. Personal best. The New Yorker; October 3, 2011. Accessed online December 1, 2011.