- Email: [email protected]
Medical students impact laparoscopic surgery case time
j o u r n a l o f s u r g i c a l r e s e a r c h 1 9 7 ( 2 0 1 5 ) 2 7 7 e2 8 2
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.JournalofSurgicalResearch.com
Medical students impact laparoscopic surgery case time Makoto Mori, BS,a Albert Liao, BS,a Thomas M. Hagopian, MD,b Sebastian D. Perez, MSPH,a Barbara J. Pettitt, MD,a and John F. Sweeney, MDa,* a
Department of Surgery, Emory University School of Medicine, Emory University, Atlanta, Georgia Division of Plastic and Reconstructive Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
b
article info
abstract
Article history:
Background: Medical students (MS) are increasingly assuming active roles in the operating
Received 6 February 2015
room. Laparoscopic cases offer unique opportunities for MS participation. The aim of this
Received in revised form
study was to examine associations between the presence of MS in laparoscopic cases and
22 March 2015
operation time and postoperative complication rates.
Accepted 3 April 2015
Materials and methods: Data from the American College of Surgeons National Surgical
Available online 9 April 2015
Quality Improvement Program were linked to operative records for nonemergent, inpatient, and laparoscopic general surgery cases at our institution from January, 2009
Keywords:
eJanuary, 2013. Cases were grouped into eight distinct procedure categories. Hospital
Medical students
records provided information on the presence of MS. Demographics, comorbidities,
Operating rooms
intraoperative variables, and postoperative complication rates were analyzed.
Operative time
Results: Seven hundred laparoscopic cases were included. Controlling for wound class,
Laparoscopic surgery
procedure group, and surgeon, MS were associated with an additional 28 min of total
University hospitals
operative time. The most significant increase occurred between the skin incision and skin closure. No significant association between the presence of MS and postoperative complications was observed. Conclusions: This is the first retrospective analysis to examine the effect of MS presence during laparoscopic procedures. Increase in the operation time associated with the presence of MS should be examined further, to optimize the educational experience without incurring increased cost due to increased operation time. ª 2015 Elsevier Inc. All rights reserved.
1.
Introduction
Laparoscopic surgery has become widely established; its growth and popularity can be directly attributed to its broad application in various abdominal procedures as well as its postoperative benefits. Advantages include reduced postsurgical complications, reduced postoperative pain, and
improved cosmetic results [1,2]. In addition, patients benefit from decreased postoperative hospital length of stay, which directly translates into lower health care costs [1]. As health care in the United States become more oriented toward cost effectiveness and patient satisfaction, the prevalence and importance of laparoscopic procedures will only continue to grow.
* Corresponding author. Department of Surgery, Emory University School of Medicine, 1365 Clifton Road, NE, Building A, Suite A5048, Atlanta, GA 30322. Tel.: þ1 404 727 1540; fax: þ1 404 727 4716. E-mail address: [email protected] (J.F. Sweeney). 0022-4804/$ e see front matter ª 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jss.2015.04.021
278
j o u r n a l o f s u r g i c a l r e s e a r c h 1 9 7 ( 2 0 1 5 ) 2 7 7 e2 8 2
In its “Recommendations for Clinical Skills Curricula for Undergraduate Medical Education,” the American Association of Medical Colleges establish that medical students (MS) should be required to master basic surgical techniques including gowning, gloving, and suturing [3]. Hands-on experience in the operating room (OR) is a critical component of MS surgical clerkships, positively transforming their perception of the field and surgeons [4] and influencing their specialty choices [5]. Camera navigation during a laparoscopic procedure represents a unique opportunity for MS to become more involved during the operation compared with that of traditional open operations. However, there is no standardized instruction in basic laparoscopic skills for MS, in particular, skills related to camera navigation such as focusing, maintaining the correct axes, and tracking instruments in motion. Students may be taught by attending surgeons, residents, technicians, or other students, resulting in variations in the individual student’s education. Involvement of inexperienced residents in operative procedures increases their length significantly [6,7], but the effects of MS’ involvement in the OR remains poorly understood. Increases in operative time translate into increased cost for the institution [6,8,9]. In addition, increased operative times represent an opportunity cost for the attending surgeon, time that could have been invested in pursuing additional research, procedures, or didactic teaching. Because of this, it is important to examine the impact of MS on operative times of laparoscopic procedures. Our hypothesis is that operative times are increased without increasing postoperative complication rates when MS are present during laparoscopic operations.
present, time stamps of checkpoints during the operation (the time of patient entry to the room, skin incision, end of skin closure, and patient exit from the OR), and the role of each person in the OR such as primary surgeon, secondary surgeon, anesthesia staff, nursing staff, students, administrative staff, and observers. Cases with at least one MS for more than 33% of the total operative time were defined as cases with a MS present. This cohort was compared against cases without MS, which were defined as cases with MS present for less than 33% of the total operative time. The 33% threshold was used to isolate cases with significant MS presence during the case without compromising the sample sizes in each cohort. The components of operative time were defined as the following: total operative time (patient entry to patient exit from the OR), in-to-incision (patient entry-to-skin incision), skin-to-skin (skin incision-to-skin closure), and closure-to-exit (skin closure-to-patient exit from the OR).
2.3.
Definition of complications
The following complications were obtained from the NSQIP report in each patient: acute renal failure, cardiac arrest, deep incisional skin site infection, vein thrombosis requiring therapy, myocardial infarction, on ventilation within 48 h postoperatively, pneumonia, pulmonary embolism, progressive renal insufficiency, cerebral vascular accident, superficial skin site infection, unplanned intubation, urinary tract infection, wound disruption, and organ space infection. Number of patients who have had at least one of the listed complications during the postoperative period were compared with patients who had undergone operations with and without the presence of MS in the OR.
2.
Material and methods
2.4.
2.1.
Case selection
Univariate analysis comparing cases with MS to those without MS was performed to identify variables that were statistically different between the groups. Categorical variables were compared with chi-square tests (or Fisher exact test where appropriate), and continuous variables (such as operative time) were compared with two sample t-tests. Univariate analysis was conducted to compare the rates of postoperative complications. Interaction variables between MS presence and procedure category were tested for significance. Variables found to be statistically significant on univariate analysis or those determined to be clinically important were included as independent variables in the final linear regression model of operative time and MS presence. P values of <0.05 were considered significant. All statistical calculations were performed using JMP 10.0 for OSX (SAS; Cary, NC).
We identified all laparoscopic general surgery cases at our institution from January 2009eJanuary 2013. The University Hospital in which the operations were performed is a 580-bed tertiary care center affiliated with our institution. Third and fourth year MS rotate at this hospital as parts of clerkship, subinternship, and electives. General surgical case volume generally exceeds the volume that can be attended by MS, resulting in cases without MS. Medical record numbers for these cases were cross-referenced with the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database to obtain demographic information, comorbidities, intraoperative variables, and postoperative complications. Emergent and ambulatory surgery cases were excluded, as these cases were much less likely to include MS participants. Reoperations due to complications and cases that were not sampled by NSQIP during the study period were also excluded.
2.2.
Definition of OR time and cases with MS
Data from NSQIP were combined with data from hospital electronic medical records. This included the number of people present for the case, the amount of time they were
3.
Statistical analysis
Results
Seven hundred cases were identified that met inclusion criteria. Using current procedural terminology codes, cases were grouped into eight procedure categories (Table 1). Patient age averaged 54 y. Slightly more than half were female and 71% were white. The largest category of cases was colectomy and/or colostomy (27%). Cholecystectomy,
j o u r n a l o f s u r g i c a l r e s e a r c h 1 9 7 ( 2 0 1 5 ) 2 7 7 e2 8 2
Table 1 e CPT codes of each procedure category. Procedure category Appendectomy Bariatric Cholecystectomy and biliary tract Colectomy and ostomy
Hernia repairs Small bowel resection Ventral hernia repair Other
CPT codes 44970 43644, 43770, 43774, 43775 47562, 47563, 47564 44187, 44188, 44204, 44205, 44206, 44207,44208, 44210, 44211, 44212, 44227, 45395, 45397, 45400 49650, 49652, 49653, 49654, 49655, 49656, 49657 44202 44180 38120, 38570, 43279, 43280, 43281, 43282, 49321, 49322, 49323,49324, 60650
CPT ¼ current procedural terminology.
appendectomy, and hernia repair were the next most commonly performed procedures in the study (18%, 17%, and 15%, respectively). Ventral hernia repair was the least performed (2%). Mean total operative time for all cases was 204 min. MS were present for 38% of the cases (Table 2). Comparison of cases with MS present to cases without students demonstrated that patients who underwent operations with MS present during their operations had statistically significant differences in dyspnea before surgery, preoperative hematocrit, procedure category, wound class, and mean operative time (Table 2). Comparing patients who underwent operations with and without the presence of MS in the OR, there was no statistically significant difference in the number of patients who experienced at least one of the defined
Table 2 e Patient characteristics. Characteristic Mean age, y (SD) Sex Male Female Race* White Nonwhite Procedure group Appendectomy Bariatric Cholecystectomy Colectomy and ostomy Hernia repairs Small bowel resection Ventral hernia repair Other Mean operation time, min (SD) In-incision time Skin-skin time Close-out Medical student present for greater than 33% of case SD ¼ standard deviation. * 19 patients with unknown race.
Laparoscopic cases, N ¼ 695 n 325 370 481 195 116 37 126 185 102 21 11 97 203 (101) 45 (15) 147 (110) 11 (56) 262
54 (17) % of total 47 53 69 28 17 5 18 27 15 3 2 14
38
279
complications during the postoperative period (14% versus 14%, P ¼ 0.95; Table 3). An interaction variable between MS presence and procedure category was tested and found to be nonsignificant, and therefore were not included in the final model. Body mass index greater than 30 was thought to be possibly clinically significant and thus was included. The final multivariate linear regression model consisted of the independent variable operative time and the dependent variables MS present for greater than 33% of the case, procedure category, wound class, body mass index greater than 30, dyspnea before surgery, and preoperative hematocrit. In the multivariate linear regression model, the presence of MS was associated with a statistically significant increase of 27.9 min in the total operative time (P < 0.05). Breaking down the total operation time into separate components, statistically significant increases were observed in the in-to-incision time and skin-to-skin time (þ2.3 and þ21.2 min, respectively; Table 4). No significant change in time was observed in close-exit time.
4.
Discussion
The present study was undertaken to investigate associations between the presence of MS and measurements of quality such as operative time and complication rates in laparoscopic procedures. Using our institutional medical record and a prospective standardized national database, we found MS’ presence in the OR associated with increased total operative and in-toincision and incision-to-close time without statistically significant difference in the postoperative complication rates. Laparoscopic cases offer a unique opportunity for MS participation. In contrast to open cases, where MS participation is typically limited to holding retractors, simple suturing, or observation, some surgeons will allow MS to drive the laparoscopic camera during the operation. This makes the MS an active participant in the operation. The camera driving technique, however, is complex and has been shown to require formal training to achieve proficiency [10]. Although the data used in this study did not allow us to examine the degree of MS involvement in this regard, we suspect that direct MS participation in the operation through camera operation may be partly responsible for the increased operative times. Monitors used in laparoscopic cases are easily visualized from anywhere in the room, allowing any MS present in the room to be taught by the surgeon regardless of participation in the operation. This increased opportunity for teaching may also be responsible for the observed increase in operative time. A previously published study from our institution documented an additional 14 min of operative time when MS were present, but that study included open and laparoscopic operations [11]. The increase in operative time that we observed in the present study lends further evidence to the unique nature of laparoscopic procedures when compared with open cases because students who are not scrubbed-in during an open case may be less likely to receive detailed teaching about anatomy or procedural steps they cannot adequately see.
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Table 3 e Comparison of laparoscopic cases with MS to cases without MS. Patient characteristics
Cases with MS, (n ¼ 267, 38%)
Mean age (y) (SD) Male, n (%) White, n (%) ASA class 3e5, n (%) BMI >30, n (%) Diabetes, n (%) COPD, n (%) Smoker, n (%) Dyspnea, n (%) History of bleeding disorder, n (%) Independent functional status, n (%) Hypertension requiring meds, n (%) Dialysis before surgery, n (%) Disseminated cancer, n (%) Transfusion before surgery, n (%) Weight loss before surgery, n (%) Preoperative laboratory, mean (SD) Sodium BUN Creatinine Albumin Total bilirubin Hematocrit Platelet Procedure category, n (% of total) Appendectomy Bariatric Cholecystectomy and biliary tract Colectomy and ostomy Hernia repairs Small bowel resection Ventral hernia and LOA Other Wound class, n (% of total) Clean Clean/contaminated Contaminated Dirty/infected Operative time (min), mean (SD) Mean In-incision Skin-skin Close-out Number of patients with at least one complication, % Any complication Primary surgeon*
Cases without MS, (n ¼ 428, 62%)
P 0.61 0.89 0.72 0.23 0.035 0.18 0.32 0.76 0.031 0.18 0.26 0.15 0.43 0.19 0.75 0.22
54.1 124 184 102 128 44 12 32 25 9 256 131 2 3 3 8
(17.2) (46.4) (68.9) (38.2) (47.9) (16.5) (4.4) (12.0) (9.4) (3.4) (9.6) (49.0) (0.7) (1.1) (1.1) (3.0)
53.5 (16.7) 201 (46.9) 297 (69.4) 193 (45.0) 170 (40.0) 55 (12.9) 13 (3.0) 48 (11.2) 22 (5.1) 24 (5.6) 402 (93.9) 186 (43.5) 6 (1.4) 11 (2.6) 6 (1.4) 21 (4.9)
138.3 12.1 1.0 3.6 0.82 37.0 240.1
(2.4) (6.6) (0.8) (0.5) (0.88) (5.1) (90.5)
138.2 (2.5) 13.3 (10.3) 1.0 (0.7) 3.6 (0.6) 0.84 (0.78) 37.5 (5.2) 234.0 (80.0)
22 16 46 77 42 12 5 47
(8.2) (6.0) (17.2) (28.8) (15.7) (4.5) (1.9) (17.6)
94 21 80 108 60 9 6 50
(21.9) (4.9) (18.7) (25.2) (14.0) (2.1) (1.4) (9.5)
0.0002
90 124 40 13
(33.7) (46.4) (15.0) (4.9)
113 185 78 52
(26.4) (43.2) (18.2) (12.1)
0.0033
186.4 (92.4) 43.0 (14.9) 130.0 (86.1) 13.4 (11.3)
<0.0001 <0.0001 <0.0001 0.46
60 (14)
0.95 0.25
231.1 47.7 170.3 13.1
(111.4) (14.7) (104.7) (6.9)
37 (14)
ASA ¼ American Society of Anesthesiologists physical status classification; BMI ¼ body mass index; BUN ¼blood urea nitrogen; COPD ¼ chronic obstructive pulmonary disease; SD ¼ standard deviation; LOA ¼ lysis of adhesions. Percentages may not add up to 100% in some cases due to rounding. Bold implies P< 0.05. * 21 surgeons, hidden for identification purposes.
In addition to examining the total operative time, as we have done in our previous study [11], the present study examined the composition of the total operative time. The time from the patient’s entrance to the OR to the time of incision (in-to-skin time) was statistically significantly increased in cases with MS present, but the overall contribution of the additional time to the total OR time was minimal (þ2 min). This suggests that patient preparation time (Foley catheter insertion, positioning, and so forth) was minimally
impacted by the presence of MS. The majority of the additional operative time occurred during the operation (skin-toskin time), suggesting that the students’ involvement in the case indeed was the major contributing factor. Rates of laparoscopic and minimally invasive surgery continue to increase. The effect of the learning environment on laparoscopic cases that is present in teaching hospitals has not been studied. If the association with MS and operative time observed in this study is indeed causal, it represents an
281
j o u r n a l o f s u r g i c a l r e s e a r c h 1 9 7 ( 2 0 1 5 ) 2 7 7 e2 8 2
Table 4 e Multivariate analysis of MS and operative time. Independent variables
MS present (y/n] Procedure category Ventral hernia and lysis of adhesions Appendectomy Bariatric Cholecystectomy and biliary tract Colectomy and ostomy Hernia repairs Small bowel resection Other Wound class Clean Clean/contaminated Contaminated Dirty/infected BMI >30 Dyspnea Hematocrit
Total operative time (mean difference [95% CI]) 27.9 [15.1e40.7]
In-to-incision (mean difference [95% CI])
Skin-to-skin (mean difference [95% CI])
Close-to-out (mean difference [95% CI])
2.3 [0.1e4.4]
21.2 [6.1e36.3]
Reference
Reference
Reference
92.6 [153.0 to 32.1] 38.6 [22.9 to 100.0] 11.7 [70.0 to 46.5]
3.1 [13.4 to 7.1] 5.8 [4.7 to 16.3] 2.7 [7.2 to 12.7]
86.9 [158.4 to 15.4] 31.1 [41.5 to 103.8] 14.5 [83.3 to 54.3]
3.0 [44.9 to 38.9] 1.5 [41.1 to 44.1] 0.1 [40.5 to 40.2]
105.9 77.1 27.4 88.0
[41.1e163.5] [20.6e133.7] [38.5 to 93.4] [32.6e143.3]
11.8 4.0 6.8 11.3
[1.9e21.6] [5.6 to 13.6] [4.4 to 18.0] [1.9e20.1]
95.8 65.4 23.6 83.0
Reference [146.0 to 54.4] [74.2 to 23.5] [29.7 to 21.0] [27.4 to 0.9] [38.4 to 12.2] [0.2 to 2.3]
Reference 2.6 [5.1 to 10.5] 0.4 [4.0 to 4.7] 3.4 [1.0 to 7.7] 1.7 [4.0 to 0.5] 1.9 [6.2 to 2.4] 0.2 [0.4 to 0.01]
89.3 43.5 3.0 17.2 4.7 1.5
Reference
100.2 48.8 4.3 14.1 13.1 1.1
[27.6e164.0] [1.4 to 132.2] [54.3 to 101.5] [143.4 to 35.2] Reference [143.4 to 35.2] [73.5 to 13.5] [32.9 to 27.0] [32.9 to 1.5] [34.6 to 25.2] [0.04 to 3.0]
4.3 [4.6 to 13.1]
1.9 8.3 3.2 6.5
[41.9 [30.8 [48.8 [44.8
to 38.1] to 47.5] to 42.5] to 31.8]
Reference 13.8 [45.5 to 18.0] 5.8 [23.4 to 11.8] 4.8 [22.4 to 12.7] 5.1 [4.1 to 14.3] 6.4 [24.0 to 11.1] 0.15 [1.0 to 0.7]
BMI ¼ body mass index; CI ¼ confidence interval. Differences in operative time among procedures shown are compared with ventral hernia repair and lysis of adhesions. For example, appendectomies have operative times that are 93 min less when compared with ventral hernia and/or lysis of adhesion cases (the reference). The presence of MS was associated with an additional 28 min of operative time. Bold implies P < 0.05.
area of potential quality improvement and cost-savings. Regardless of the operative-time increase, there was no statistically significant association between MS presence in the OR and postoperative complications. We hope that this reassuring result will allow MS to continue to assume an active role in the OR and in postoperative patient care. A limitation of this study is that it is retrospective. A prospective study is necessary to determine the true relationship between MS and operative time. Current standardized laparoscopic training programs for surgery residents [12] could be adapted for MS and incorporated into the surgery clerkship, potentially resulting in increased willingness to involve MS in laparoscopic procedures and decreased operative times when they participate. From the abstracted intraoperative reports, it was not possible to determine the degree of students’ involvement in the surgical procedure (i.e., camera driving). Although we did not examine residents’ presence in the cases as a confounding factor, residents cover essentially all general surgical cases at our University Hospital. Therefore, we did not feel the need to control for this element in our analysis. Finally, this study was conducted at a single-academic institution, and although MS participation in the OR may be generalized across the country, hospital settings may be different, limiting the external validity of these results.
5.
Conclusions
To our knowledge, this is the first study to examine the association between the presence of MS during laparoscopic cases and postoperative outcomes. The presence of MS was
associated with increased operative time but not postoperative complication rates. Further study is needed to identify the cause of this operative time increase to find ways to minimize it without compromising MS surgery education.
Acknowledgment We thank Atlanta Clinical and Translational Science Institute and Mr. Jeff Weaver for technical supports in the process of data acquisition. Authors’ contributions: M.M. and T.M.H. contributed to the data acquisition. M.M., A.L., B.J.P., and J.F.S. contributed to the article preparation. T.M.H., B.J.P., and J.F.S. did the study design. T.M.H. did the statistical analysis. S.D.P. did the data interpretation. B.J.P. and J.F.S. did the supervision. All authors approved this article.
Disclosure The authors reported no proprietary or commercial interest in any product mentioned or concept discussed in this article. The authors declared no conflict of interest.
references
[1] Nguyen NT, Goldman C, Rosenquist J, et al. Laparoscopic versus open gastric bypass: a randomized study of outcomes, quality of life, and costs. Ann Surg 2001;234:279.
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[2] Ding J, Xia Y, Liao GQ, et al. Hand-assisted laparoscopic surgery versus open surgery for colorectal disease: a systematic review and meta-analysis. Am J Surg 2014;207:109. [3] Danoff D, Corbett E, Fortin A, Lown B, Novak D. Recommendations for clinical skills curricula for undergraduate medical education. Task Force on the Clinical Skills Education of Medical Students, Association of American Medical Colleges; Washington, DC, 2005:42. http:// www.aamc.org/meded/clinicalskills/ [4] Berman L, Rosenthal MS, Curry LA, Evans LV, Gusberg RJ. Attracting surgical clerks to surgical careers: role models, mentoring, and engagement in the operating room. J Am Coll Surg 2008;207:793. [5] O’Herrin JK, Lewis BJ, Rikkers LF, Chen H. Medical student operative experience correlates with a match to a categorical surgical program. Am J Surg 2003;186:125. [6] Babineau TJ, Becker J, Gibbons G, et al. The “cost” of operative training for surgical residents. Arch Surg 2004;139:366. discussion 369e70.
[7] Raval MV, Wang X, Cohen ME, et al. The influence of resident involvement on surgical outcomes. J Am Coll Surg 2011;212: 889. [8] Bridges M, Diamond DL. The financial impact of teaching surgical residents in the operating room. Am J Surg 1999; 177:28. [9] Harrington DT, Roye GD, Ryder BA, Miner TJ, Richardson P, Cioffi WG. A time-cost analysis of teaching a laparoscopic entero-enterostomy. J Surg Educ 2007;64:342. [10] Franzeck FM, Rosenthal R, Muller MK, et al. Prospective randomized controlled trial of simulator-based versus traditional in-surgery laparoscopic camera navigation training. Surg Endosc 2012;26:235. [11] Hagopian TM, Vitiello GA, Hart AM, Perez SD, Pettitt BJ, Sweeney JF. Do medical students in the operating room affect patient care? An analysis of one institution’s experience over the past five years. J Surg Educ 2014;71:817. [12] Fundamentals of laparoscopic surgery. http://www.FLS.org, Accessed 23 Jan 2015.
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.JournalofSurgicalResearch.com
Medical students impact laparoscopic surgery case time Makoto Mori, BS,a Albert Liao, BS,a Thomas M. Hagopian, MD,b Sebastian D. Perez, MSPH,a Barbara J. Pettitt, MD,a and John F. Sweeney, MDa,* a
Department of Surgery, Emory University School of Medicine, Emory University, Atlanta, Georgia Division of Plastic and Reconstructive Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California
b
article info
abstract
Article history:
Background: Medical students (MS) are increasingly assuming active roles in the operating
Received 6 February 2015
room. Laparoscopic cases offer unique opportunities for MS participation. The aim of this
Received in revised form
study was to examine associations between the presence of MS in laparoscopic cases and
22 March 2015
operation time and postoperative complication rates.
Accepted 3 April 2015
Materials and methods: Data from the American College of Surgeons National Surgical
Available online 9 April 2015
Quality Improvement Program were linked to operative records for nonemergent, inpatient, and laparoscopic general surgery cases at our institution from January, 2009
Keywords:
eJanuary, 2013. Cases were grouped into eight distinct procedure categories. Hospital
Medical students
records provided information on the presence of MS. Demographics, comorbidities,
Operating rooms
intraoperative variables, and postoperative complication rates were analyzed.
Operative time
Results: Seven hundred laparoscopic cases were included. Controlling for wound class,
Laparoscopic surgery
procedure group, and surgeon, MS were associated with an additional 28 min of total
University hospitals
operative time. The most significant increase occurred between the skin incision and skin closure. No significant association between the presence of MS and postoperative complications was observed. Conclusions: This is the first retrospective analysis to examine the effect of MS presence during laparoscopic procedures. Increase in the operation time associated with the presence of MS should be examined further, to optimize the educational experience without incurring increased cost due to increased operation time. ª 2015 Elsevier Inc. All rights reserved.
1.
Introduction
Laparoscopic surgery has become widely established; its growth and popularity can be directly attributed to its broad application in various abdominal procedures as well as its postoperative benefits. Advantages include reduced postsurgical complications, reduced postoperative pain, and
improved cosmetic results [1,2]. In addition, patients benefit from decreased postoperative hospital length of stay, which directly translates into lower health care costs [1]. As health care in the United States become more oriented toward cost effectiveness and patient satisfaction, the prevalence and importance of laparoscopic procedures will only continue to grow.
* Corresponding author. Department of Surgery, Emory University School of Medicine, 1365 Clifton Road, NE, Building A, Suite A5048, Atlanta, GA 30322. Tel.: þ1 404 727 1540; fax: þ1 404 727 4716. E-mail address: [email protected] (J.F. Sweeney). 0022-4804/$ e see front matter ª 2015 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jss.2015.04.021
278
j o u r n a l o f s u r g i c a l r e s e a r c h 1 9 7 ( 2 0 1 5 ) 2 7 7 e2 8 2
In its “Recommendations for Clinical Skills Curricula for Undergraduate Medical Education,” the American Association of Medical Colleges establish that medical students (MS) should be required to master basic surgical techniques including gowning, gloving, and suturing [3]. Hands-on experience in the operating room (OR) is a critical component of MS surgical clerkships, positively transforming their perception of the field and surgeons [4] and influencing their specialty choices [5]. Camera navigation during a laparoscopic procedure represents a unique opportunity for MS to become more involved during the operation compared with that of traditional open operations. However, there is no standardized instruction in basic laparoscopic skills for MS, in particular, skills related to camera navigation such as focusing, maintaining the correct axes, and tracking instruments in motion. Students may be taught by attending surgeons, residents, technicians, or other students, resulting in variations in the individual student’s education. Involvement of inexperienced residents in operative procedures increases their length significantly [6,7], but the effects of MS’ involvement in the OR remains poorly understood. Increases in operative time translate into increased cost for the institution [6,8,9]. In addition, increased operative times represent an opportunity cost for the attending surgeon, time that could have been invested in pursuing additional research, procedures, or didactic teaching. Because of this, it is important to examine the impact of MS on operative times of laparoscopic procedures. Our hypothesis is that operative times are increased without increasing postoperative complication rates when MS are present during laparoscopic operations.
present, time stamps of checkpoints during the operation (the time of patient entry to the room, skin incision, end of skin closure, and patient exit from the OR), and the role of each person in the OR such as primary surgeon, secondary surgeon, anesthesia staff, nursing staff, students, administrative staff, and observers. Cases with at least one MS for more than 33% of the total operative time were defined as cases with a MS present. This cohort was compared against cases without MS, which were defined as cases with MS present for less than 33% of the total operative time. The 33% threshold was used to isolate cases with significant MS presence during the case without compromising the sample sizes in each cohort. The components of operative time were defined as the following: total operative time (patient entry to patient exit from the OR), in-to-incision (patient entry-to-skin incision), skin-to-skin (skin incision-to-skin closure), and closure-to-exit (skin closure-to-patient exit from the OR).
2.3.
Definition of complications
The following complications were obtained from the NSQIP report in each patient: acute renal failure, cardiac arrest, deep incisional skin site infection, vein thrombosis requiring therapy, myocardial infarction, on ventilation within 48 h postoperatively, pneumonia, pulmonary embolism, progressive renal insufficiency, cerebral vascular accident, superficial skin site infection, unplanned intubation, urinary tract infection, wound disruption, and organ space infection. Number of patients who have had at least one of the listed complications during the postoperative period were compared with patients who had undergone operations with and without the presence of MS in the OR.
2.
Material and methods
2.4.
2.1.
Case selection
Univariate analysis comparing cases with MS to those without MS was performed to identify variables that were statistically different between the groups. Categorical variables were compared with chi-square tests (or Fisher exact test where appropriate), and continuous variables (such as operative time) were compared with two sample t-tests. Univariate analysis was conducted to compare the rates of postoperative complications. Interaction variables between MS presence and procedure category were tested for significance. Variables found to be statistically significant on univariate analysis or those determined to be clinically important were included as independent variables in the final linear regression model of operative time and MS presence. P values of <0.05 were considered significant. All statistical calculations were performed using JMP 10.0 for OSX (SAS; Cary, NC).
We identified all laparoscopic general surgery cases at our institution from January 2009eJanuary 2013. The University Hospital in which the operations were performed is a 580-bed tertiary care center affiliated with our institution. Third and fourth year MS rotate at this hospital as parts of clerkship, subinternship, and electives. General surgical case volume generally exceeds the volume that can be attended by MS, resulting in cases without MS. Medical record numbers for these cases were cross-referenced with the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database to obtain demographic information, comorbidities, intraoperative variables, and postoperative complications. Emergent and ambulatory surgery cases were excluded, as these cases were much less likely to include MS participants. Reoperations due to complications and cases that were not sampled by NSQIP during the study period were also excluded.
2.2.
Definition of OR time and cases with MS
Data from NSQIP were combined with data from hospital electronic medical records. This included the number of people present for the case, the amount of time they were
3.
Statistical analysis
Results
Seven hundred cases were identified that met inclusion criteria. Using current procedural terminology codes, cases were grouped into eight procedure categories (Table 1). Patient age averaged 54 y. Slightly more than half were female and 71% were white. The largest category of cases was colectomy and/or colostomy (27%). Cholecystectomy,
j o u r n a l o f s u r g i c a l r e s e a r c h 1 9 7 ( 2 0 1 5 ) 2 7 7 e2 8 2
Table 1 e CPT codes of each procedure category. Procedure category Appendectomy Bariatric Cholecystectomy and biliary tract Colectomy and ostomy
Hernia repairs Small bowel resection Ventral hernia repair Other
CPT codes 44970 43644, 43770, 43774, 43775 47562, 47563, 47564 44187, 44188, 44204, 44205, 44206, 44207,44208, 44210, 44211, 44212, 44227, 45395, 45397, 45400 49650, 49652, 49653, 49654, 49655, 49656, 49657 44202 44180 38120, 38570, 43279, 43280, 43281, 43282, 49321, 49322, 49323,49324, 60650
CPT ¼ current procedural terminology.
appendectomy, and hernia repair were the next most commonly performed procedures in the study (18%, 17%, and 15%, respectively). Ventral hernia repair was the least performed (2%). Mean total operative time for all cases was 204 min. MS were present for 38% of the cases (Table 2). Comparison of cases with MS present to cases without students demonstrated that patients who underwent operations with MS present during their operations had statistically significant differences in dyspnea before surgery, preoperative hematocrit, procedure category, wound class, and mean operative time (Table 2). Comparing patients who underwent operations with and without the presence of MS in the OR, there was no statistically significant difference in the number of patients who experienced at least one of the defined
Table 2 e Patient characteristics. Characteristic Mean age, y (SD) Sex Male Female Race* White Nonwhite Procedure group Appendectomy Bariatric Cholecystectomy Colectomy and ostomy Hernia repairs Small bowel resection Ventral hernia repair Other Mean operation time, min (SD) In-incision time Skin-skin time Close-out Medical student present for greater than 33% of case SD ¼ standard deviation. * 19 patients with unknown race.
Laparoscopic cases, N ¼ 695 n 325 370 481 195 116 37 126 185 102 21 11 97 203 (101) 45 (15) 147 (110) 11 (56) 262
54 (17) % of total 47 53 69 28 17 5 18 27 15 3 2 14
38
279
complications during the postoperative period (14% versus 14%, P ¼ 0.95; Table 3). An interaction variable between MS presence and procedure category was tested and found to be nonsignificant, and therefore were not included in the final model. Body mass index greater than 30 was thought to be possibly clinically significant and thus was included. The final multivariate linear regression model consisted of the independent variable operative time and the dependent variables MS present for greater than 33% of the case, procedure category, wound class, body mass index greater than 30, dyspnea before surgery, and preoperative hematocrit. In the multivariate linear regression model, the presence of MS was associated with a statistically significant increase of 27.9 min in the total operative time (P < 0.05). Breaking down the total operation time into separate components, statistically significant increases were observed in the in-to-incision time and skin-to-skin time (þ2.3 and þ21.2 min, respectively; Table 4). No significant change in time was observed in close-exit time.
4.
Discussion
The present study was undertaken to investigate associations between the presence of MS and measurements of quality such as operative time and complication rates in laparoscopic procedures. Using our institutional medical record and a prospective standardized national database, we found MS’ presence in the OR associated with increased total operative and in-toincision and incision-to-close time without statistically significant difference in the postoperative complication rates. Laparoscopic cases offer a unique opportunity for MS participation. In contrast to open cases, where MS participation is typically limited to holding retractors, simple suturing, or observation, some surgeons will allow MS to drive the laparoscopic camera during the operation. This makes the MS an active participant in the operation. The camera driving technique, however, is complex and has been shown to require formal training to achieve proficiency [10]. Although the data used in this study did not allow us to examine the degree of MS involvement in this regard, we suspect that direct MS participation in the operation through camera operation may be partly responsible for the increased operative times. Monitors used in laparoscopic cases are easily visualized from anywhere in the room, allowing any MS present in the room to be taught by the surgeon regardless of participation in the operation. This increased opportunity for teaching may also be responsible for the observed increase in operative time. A previously published study from our institution documented an additional 14 min of operative time when MS were present, but that study included open and laparoscopic operations [11]. The increase in operative time that we observed in the present study lends further evidence to the unique nature of laparoscopic procedures when compared with open cases because students who are not scrubbed-in during an open case may be less likely to receive detailed teaching about anatomy or procedural steps they cannot adequately see.
280
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Table 3 e Comparison of laparoscopic cases with MS to cases without MS. Patient characteristics
Cases with MS, (n ¼ 267, 38%)
Mean age (y) (SD) Male, n (%) White, n (%) ASA class 3e5, n (%) BMI >30, n (%) Diabetes, n (%) COPD, n (%) Smoker, n (%) Dyspnea, n (%) History of bleeding disorder, n (%) Independent functional status, n (%) Hypertension requiring meds, n (%) Dialysis before surgery, n (%) Disseminated cancer, n (%) Transfusion before surgery, n (%) Weight loss before surgery, n (%) Preoperative laboratory, mean (SD) Sodium BUN Creatinine Albumin Total bilirubin Hematocrit Platelet Procedure category, n (% of total) Appendectomy Bariatric Cholecystectomy and biliary tract Colectomy and ostomy Hernia repairs Small bowel resection Ventral hernia and LOA Other Wound class, n (% of total) Clean Clean/contaminated Contaminated Dirty/infected Operative time (min), mean (SD) Mean In-incision Skin-skin Close-out Number of patients with at least one complication, % Any complication Primary surgeon*
Cases without MS, (n ¼ 428, 62%)
P 0.61 0.89 0.72 0.23 0.035 0.18 0.32 0.76 0.031 0.18 0.26 0.15 0.43 0.19 0.75 0.22
54.1 124 184 102 128 44 12 32 25 9 256 131 2 3 3 8
(17.2) (46.4) (68.9) (38.2) (47.9) (16.5) (4.4) (12.0) (9.4) (3.4) (9.6) (49.0) (0.7) (1.1) (1.1) (3.0)
53.5 (16.7) 201 (46.9) 297 (69.4) 193 (45.0) 170 (40.0) 55 (12.9) 13 (3.0) 48 (11.2) 22 (5.1) 24 (5.6) 402 (93.9) 186 (43.5) 6 (1.4) 11 (2.6) 6 (1.4) 21 (4.9)
138.3 12.1 1.0 3.6 0.82 37.0 240.1
(2.4) (6.6) (0.8) (0.5) (0.88) (5.1) (90.5)
138.2 (2.5) 13.3 (10.3) 1.0 (0.7) 3.6 (0.6) 0.84 (0.78) 37.5 (5.2) 234.0 (80.0)
22 16 46 77 42 12 5 47
(8.2) (6.0) (17.2) (28.8) (15.7) (4.5) (1.9) (17.6)
94 21 80 108 60 9 6 50
(21.9) (4.9) (18.7) (25.2) (14.0) (2.1) (1.4) (9.5)
0.0002
90 124 40 13
(33.7) (46.4) (15.0) (4.9)
113 185 78 52
(26.4) (43.2) (18.2) (12.1)
0.0033
186.4 (92.4) 43.0 (14.9) 130.0 (86.1) 13.4 (11.3)
<0.0001 <0.0001 <0.0001 0.46
60 (14)
0.95 0.25
231.1 47.7 170.3 13.1
(111.4) (14.7) (104.7) (6.9)
37 (14)
ASA ¼ American Society of Anesthesiologists physical status classification; BMI ¼ body mass index; BUN ¼blood urea nitrogen; COPD ¼ chronic obstructive pulmonary disease; SD ¼ standard deviation; LOA ¼ lysis of adhesions. Percentages may not add up to 100% in some cases due to rounding. Bold implies P< 0.05. * 21 surgeons, hidden for identification purposes.
In addition to examining the total operative time, as we have done in our previous study [11], the present study examined the composition of the total operative time. The time from the patient’s entrance to the OR to the time of incision (in-to-skin time) was statistically significantly increased in cases with MS present, but the overall contribution of the additional time to the total OR time was minimal (þ2 min). This suggests that patient preparation time (Foley catheter insertion, positioning, and so forth) was minimally
impacted by the presence of MS. The majority of the additional operative time occurred during the operation (skin-toskin time), suggesting that the students’ involvement in the case indeed was the major contributing factor. Rates of laparoscopic and minimally invasive surgery continue to increase. The effect of the learning environment on laparoscopic cases that is present in teaching hospitals has not been studied. If the association with MS and operative time observed in this study is indeed causal, it represents an
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Table 4 e Multivariate analysis of MS and operative time. Independent variables
MS present (y/n] Procedure category Ventral hernia and lysis of adhesions Appendectomy Bariatric Cholecystectomy and biliary tract Colectomy and ostomy Hernia repairs Small bowel resection Other Wound class Clean Clean/contaminated Contaminated Dirty/infected BMI >30 Dyspnea Hematocrit
Total operative time (mean difference [95% CI]) 27.9 [15.1e40.7]
In-to-incision (mean difference [95% CI])
Skin-to-skin (mean difference [95% CI])
Close-to-out (mean difference [95% CI])
2.3 [0.1e4.4]
21.2 [6.1e36.3]
Reference
Reference
Reference
92.6 [153.0 to 32.1] 38.6 [22.9 to 100.0] 11.7 [70.0 to 46.5]
3.1 [13.4 to 7.1] 5.8 [4.7 to 16.3] 2.7 [7.2 to 12.7]
86.9 [158.4 to 15.4] 31.1 [41.5 to 103.8] 14.5 [83.3 to 54.3]
3.0 [44.9 to 38.9] 1.5 [41.1 to 44.1] 0.1 [40.5 to 40.2]
105.9 77.1 27.4 88.0
[41.1e163.5] [20.6e133.7] [38.5 to 93.4] [32.6e143.3]
11.8 4.0 6.8 11.3
[1.9e21.6] [5.6 to 13.6] [4.4 to 18.0] [1.9e20.1]
95.8 65.4 23.6 83.0
Reference [146.0 to 54.4] [74.2 to 23.5] [29.7 to 21.0] [27.4 to 0.9] [38.4 to 12.2] [0.2 to 2.3]
Reference 2.6 [5.1 to 10.5] 0.4 [4.0 to 4.7] 3.4 [1.0 to 7.7] 1.7 [4.0 to 0.5] 1.9 [6.2 to 2.4] 0.2 [0.4 to 0.01]
89.3 43.5 3.0 17.2 4.7 1.5
Reference
100.2 48.8 4.3 14.1 13.1 1.1
[27.6e164.0] [1.4 to 132.2] [54.3 to 101.5] [143.4 to 35.2] Reference [143.4 to 35.2] [73.5 to 13.5] [32.9 to 27.0] [32.9 to 1.5] [34.6 to 25.2] [0.04 to 3.0]
4.3 [4.6 to 13.1]
1.9 8.3 3.2 6.5
[41.9 [30.8 [48.8 [44.8
to 38.1] to 47.5] to 42.5] to 31.8]
Reference 13.8 [45.5 to 18.0] 5.8 [23.4 to 11.8] 4.8 [22.4 to 12.7] 5.1 [4.1 to 14.3] 6.4 [24.0 to 11.1] 0.15 [1.0 to 0.7]
BMI ¼ body mass index; CI ¼ confidence interval. Differences in operative time among procedures shown are compared with ventral hernia repair and lysis of adhesions. For example, appendectomies have operative times that are 93 min less when compared with ventral hernia and/or lysis of adhesion cases (the reference). The presence of MS was associated with an additional 28 min of operative time. Bold implies P < 0.05.
area of potential quality improvement and cost-savings. Regardless of the operative-time increase, there was no statistically significant association between MS presence in the OR and postoperative complications. We hope that this reassuring result will allow MS to continue to assume an active role in the OR and in postoperative patient care. A limitation of this study is that it is retrospective. A prospective study is necessary to determine the true relationship between MS and operative time. Current standardized laparoscopic training programs for surgery residents [12] could be adapted for MS and incorporated into the surgery clerkship, potentially resulting in increased willingness to involve MS in laparoscopic procedures and decreased operative times when they participate. From the abstracted intraoperative reports, it was not possible to determine the degree of students’ involvement in the surgical procedure (i.e., camera driving). Although we did not examine residents’ presence in the cases as a confounding factor, residents cover essentially all general surgical cases at our University Hospital. Therefore, we did not feel the need to control for this element in our analysis. Finally, this study was conducted at a single-academic institution, and although MS participation in the OR may be generalized across the country, hospital settings may be different, limiting the external validity of these results.
5.
Conclusions
To our knowledge, this is the first study to examine the association between the presence of MS during laparoscopic cases and postoperative outcomes. The presence of MS was
associated with increased operative time but not postoperative complication rates. Further study is needed to identify the cause of this operative time increase to find ways to minimize it without compromising MS surgery education.
Acknowledgment We thank Atlanta Clinical and Translational Science Institute and Mr. Jeff Weaver for technical supports in the process of data acquisition. Authors’ contributions: M.M. and T.M.H. contributed to the data acquisition. M.M., A.L., B.J.P., and J.F.S. contributed to the article preparation. T.M.H., B.J.P., and J.F.S. did the study design. T.M.H. did the statistical analysis. S.D.P. did the data interpretation. B.J.P. and J.F.S. did the supervision. All authors approved this article.
Disclosure The authors reported no proprietary or commercial interest in any product mentioned or concept discussed in this article. The authors declared no conflict of interest.
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