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Single-Use Energy Sources and Operating Room Time for Laparoscopic Hysterectomy: A Randomized Controlled Trial
Original Article
Single-Use Energy Sources and Operating Room Time for Laparoscopic Hysterectomy: A Randomized Controlled Trial M. Brigid Holloran-Schwartz, MD*, Jeffrey A. Gavard, PhD, Jared C. Martin, MD, Robert J. Blaskiewicz, MD, and Patrick P. Yeung, Jr, MD From the Department of Obstetrics, Gynecology, and Women’s Health, Saint Louis University School of Medicine, Saint Louis, Missouri (all authors).
ABSTRACT Study Objectives: To compare the intraoperative direct costs of a single-use energy device with reusable energy devices during laparoscopic hysterectomy. Design: A randomized controlled trial (Canadian Task Force Classification I). Setting: An academic hospital. Patients: Forty-six women who underwent laparoscopic hysterectomy from March 2013 to September 2013. Interventions: Each patient served as her own control. One side of the uterine attachments was desiccated and transected with the single-use device (Ligasure 5-mm Blunt Tip LF1537 with the Force Triad generator). The other side was desiccated and transected with reusable bipolar forceps (RoBi 5 mm), and transected with monopolar scissors using the same Covidien Force Triad generator. The instrument approach used was randomized to the attending physician who was always on the patient’s left side. Resident physicians always operated on the patient’s right side and used the converse instruments of the attending physician. Measurements and Main Results: Start time was recorded at the utero-ovarian pedicle and end time was recorded after transection of the uterine artery on the same side. Costs included the single-use device; amortized costs of the generator, reusable instruments, and cords; cleaning and packaging of reusable instruments; and disposal of the single-use device. Operating room time was $94.14/min. We estimated that our single use-device cost $630.14 and had a total time savings of 6.7 min per case, or 3.35 min per side, which could justify the expense of the device. The single-use energy device had significant median time savings (24.7 min per side, p , .001) and total intraoperative direct cost savings ($254.16 per case). Conclusions: A single-use energy device that both desiccates and cuts significantly reduced operating room time to justify its own cost, and it also reduced total intraoperative direct costs during laparoscopic hysterectomy in our institution. Operating room cost per minute varies between institutions and must be considered before generalizing our results. Journal of Minimally Invasive Gynecology (2016) 23, 72–77 Ó 2016 AAGL. All rights reserved. Keywords:
DISCUSS
Costs; Laparoscopic hysterectomy; Operating room time; Reusable energy devices; Single-use energy device
You can discuss this article with its authors and with other AAGL members at http:// www.AAGL.org/jmig-22-6-JMIG-D-14-00562.
Use your Smartphone to scan this QR code and connect to the discussion forum for this article now* * Download a free QR Code scanner by searching for ‘‘QR scanner’’ in your smartphone’s app store or app marketplace.
Presented at the 2013 Global Congress of the American Association of Gynecologic Laparoscopists, November 11–14, 2013, Washington, D.C. Corresponding author: M. Brigid Holloran-Schwartz, MD, Department of Obstetrics, Gynecology, and Women’s Health, Saint Louis University School of Medicine, 6420 Clayton Road, Suite 230, Saint Louis, MO 63117. E-mail: [email protected] Submitted November 10, 2014. Accepted for publication August 19, 2015. Available at www.sciencedirect.com and www.jmig.org 1553-4650/$ - see front matter Ó 2016 AAGL. All rights reserved. http://dx.doi.org/10.1016/j.jmig.2015.08.881
Single-use bipolar radiofrequency hybrid devices are available that can both desiccate and cut vascular tissue during surgery with an integrated mechanical knife, but these devices add costs to the procedure. The Ligasure 5-mm Blunt Tip LF1537 (Covidien, Dublin, Ireland) desiccates tissue with impedance feedback using the Force Triad Generator (Covidien, Dublin, Ireland) and cuts using an integrated mechanical knife. With this device, an audible signal denotes when impedance rises to a level that suggests complete
Holloran-Schwartz et al.
Single-Use Energy Source and Operating Time
desiccation of the tissue between the 2 electrodes embedded in each jaw of the device; this creates a seal that can withstand 3 times the normal systolic blood pressure [1–3]. Several studies in the gastrointestinal literature that used a variety of Ligasure models have demonstrated a decrease in operating room time and/or blood loss compared with instruments that use ultrasonic or conventional radiofrequency energy [4–8]. A variety of Ligasure models have also been described for use in vaginal and laparoscopic hysterectomies [9–12]. Costs that should be considered when using a single-use radiofrequency device for a laparoscopic hysterectomy would be the purchase price of the single unit, the capital and amortized cost of the electrosurgical generator needed, and the cost of disposing of the instrument. Although some facilities ‘‘refurbish’’ these devices, this study focused on the cost as a single-use device. Alternatively, at our hospital, if a reusable approach is chosen to perform a laparoscopic hysterectomy, a 5-mm Rotating Bipolar Forcep (RoBi; Karl Storz, Tuttlingen, Germany) is available that can desiccate vascular tissue, and a reusable 5-mm monopolar scissor (model 34425 mA, Karl Storz) that can transect tissue is also available. Costs that should be considered when using reusable instruments are the capital and amortized costs of the instruments, with cords, repairs, and cleaning, and processing during its theoretical 100-use lifetime, as well as the capital and amortized costs of the electrosurgical generator needed. The purpose of this study was to determine if a single-use device that desiccates and cuts tissue during laparoscopic hysterectomy at an academic institution with resident physicians as first assistants could reduce operating room time and costs enough to justify its expense, when these and other intraoperative direct costs were compared between singleuse and reusable devices. Materials and Methods This study was approved by the Institutional Review Board of both St. Louis University and St. Mary’s Health Center. All women ages 18 years or older who presented for laparoscopic hysterectomy from March 2013 to September 2013 were asked to participate. They gave written consent to 1 of the 2 attending physicians (MBHS and PY) on the day of surgery. Both attending physicians have performed .500 laparoscopic hysterectomies. Exclusion criteria included age younger than 18 years, suspected malignancy, or if the first assistant was another attending physician, surgical assistant, or fellow. Inclusion criteria required a resident physician to be the first assistant. We chose a unique study design in which each patient could serve as her own control, and the energy source used on each side of the uterus was randomized. We used the Ligasure 5-mm Blunt Tip LF1537, using the Force Triad Electrosurgical Generator (software version 3.5 on a 2-bar standard setting that was never adjusted) to desiccate and transect 1 ‘‘side’’ of the uterine attachments. For each
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pedicle, including the uterine artery that was secured at the level of the internal os, 2 applications using the Ligasure were applied before transecting with the mechanical blade. Two reusable devices were used to desiccate and transect the other side. The reusable RoBi 5-mm Forceps were used to desiccate tissue using the same Force Triad Electrosurgical Generator at a standard setting of 35 W for bipolar coagulation. The attending physician subjectively assessed if desiccation had been achieved by visual and tactile feedback. The reusable 5-mm monopolar scissors (model 34425 mA, Karl Storz), which is standard for any laparoscopic tray at our hospital, was used to transect tissues using the Force Triad Electrosurgical Generator, with a cutting current of 30 W. The uterine artery was always secured and transected at the level of the internal os. The attending physician always operated on the left side of the patient, and the resident operated on the right. The resident always completed their side first. We hoped that patients serving as their own controls would help control for other patient specific characteristics that could contribute to surgical difficulty (e.g., body mass index, uterine size, uterine shape, adhesions, and mobility). Once consent was obtained before the start of the procedure, a blank, sealed, opaque envelope with paper inserts was randomly chosen after shuffling a container that held all of the envelopes. These sealed envelopes were kept in a locked office with the 30 inserts designated ‘‘reusable’’ and 30 inserts designated ‘‘disposable’’ (for the single-use device). If the insert with disposable was chosen, the attending physician used the single-use device. If the reusable insert was chosen, the attending physician used the reusable instrument approach. At the start of the procedure, adhesiolysis was performed, and the anatomy was normalized when needed before the start of the hysterectomy and recording of the times of the procedure. A side was defined as desiccation and transection of all upper pedicles, starting with the utero-ovarian (start time), fallopian tube and round ligament, to the final transection of the uterine artery (stop time). Adnexa were removed after the hysterectomy when indicated; these were not included in our analysis. The anterior leaf of the broad ligament was reflected inferiorly on each side using the designated energy source only to skeletonize the uterine vessels and safely displace the bladder. The full development of the bladder flap was not recorded in either side time, because the stopwatch was stopped and restarted when this plane needed to be developed to protect the bladder. Time was recorded in seconds by a medical student or circulating nurse, and was not discussed with the surgeons during the procedure. Colpotomy time was not included in the analysis. Data were entered into a database by a resident physician (JM) and validated by the statistician (JG). We considered the following costs of the single-use device (the Ligasure 5-mm Blunt Tip): the purchase price of the device ($630); the amortized cost of the Force Triad generator (software version 3.5); and the disposal fee of
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the device. The capital cost of the generator was $34,000, with the cost per case estimated to be $0.51. This was calculated by taking the original cost, dividing it by 10 years of use, and estimating that 90% of the surgical cases done in the hospital would use the generator. In our hospital, we use the same generator for the reusable approach, thus negating this cost. The disposal cost was estimated based on the total cost of disposing equipment at St. Mary’s Health Center for an entire year per pound converted to grams. The weight of the single-use device is 270 g, with a disposal cost of $0.11. We recognized, but did not calculate, the burden to the environment this additional waste would add. Costs that were considered with the reusable device, the RoBi Forceps included the amortized costs of the device and associated cord. The capital cost of the RoBi Forceps was $1200, with an additional cost of $270 for the cord. Both have a theoretical 100-use lifetime. The respective amortized costs of the RoBi and the cord thus were $12.00 and $2.70. Again, the same Force Triad generator was used for both arms of the study at a cost of $0.51/case. The reusable scissors used for transection and colpotomy are standard for any laparoscopic tray at our facility. They were required for the completion of the hysterectomy using this technique, regardless of which coagulation device was used, and therefore, they were not included in our analysis. Our hospital was unable to provide us with a cost for cleaning and repackaging reusable instruments; we therefore used an estimation from ‘‘Economics and Energy Sources,’’ by Munro of $15.00 [13]. The sample size was determined by estimating the mean time for vessel sealing and cutting (including an uncomplicated bladder flap), which was 20 min for both sides, with 70% of all cases being completed within 35 min (62 SDs). We considered our major costs to be the cost of the single-use device of $630.14 and operating room time of $94.14/min. The $94.14/min included support staff salaries, drapes, room maintenance, and use of the nonchargeable items (e.g., blankets, and so on). Costs did not include the professional fees of the surgeon or anesthesia staff. A time savings of 3.35 min per side with the single-use device at an a level of 0.05 and a level of power of 0.80 required a sample size of 45 women. Continuous variables were expressed as medians and ranges due to the lack of normality of the distributions. Categorical variables were expressed as numbers and percentages. Differences in uterine vessel desiccation and electrosurgical cutting time between single-use and reusable devices within patients were compared using the Wilcoxon signed rank test. Differences in uterine vessel desiccation and electrosurgical cutting time were compared between single-use and reusable devices for attending physicians and residents separately by using the independent Student’s t test for data, were normally distributed. The KolmogorovSmirnov test was used for data that were not normally distributed. Total single-use and reusable device intraoperative direct costs per case were estimated through itemized
Journal of Minimally Invasive Gynecology, Vol 23, No 1, January 2016
Fig. 1 Flow of participants through the study.
costs for the device, disposal, the generator, cord, cleaning and packaging, and operating room time differential. A p value of , .05 was used to denote statistical significance. All analyses were performed using SPSS (version 19.0 for Windows, IBM, Armonk, New York).
Table 1 Patient characteristics and operation data for 46 total laparoscopic hysterectomy patients Characteristic
All patients (N 5 46)
Age, yr 39.5 (34.0–46.5) 29.4 (24.0–36.9) BMI, kg/m2 Smoking, n (%) 11 (23.9) Chronic hypertension, n (%) 6 (13.0) Diabetes (any type), n (%) 2 (4.3) Gravidity 2 (0–3) Parity 1.0 (0–2.3) Uterine weight, gm 140 (100–360) Fibroids, n (%) 24 (52.2) Complications,a n (%) 1 (2.2) Estimated blood loss (mL) 75 (50–100) Morcellation, n (%) 15 (32.6) Left side (attending physician) device assignment Single use, n (%) 24 (52.2) Reusable, n (%) 22 (47.8) Left side uterine vessel desiccation and 11.4 (7.6–15.6) electrosurgical cutting time, min Right side (resident) device assignment Single use, n (%) 22 (47.8) Reusable, n (%) 24 (52.2) Right side uterine vessel desiccation and 10.1 (7.7–19.9) electrosurgical cutting time, min Total case time, min, median (IQR) 129 (101–167) BMI 5 body mass index. Data are median (interquartile [IQR]), unless noted otherwise. Uterine weight was unknown for 1 woman, and total case time was unknown for 10 women. a Cystotomy occurred in 1 woman.
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Results The flow of participants through the study is shown in Fig. 1. Fifty-two women gave informed consent, 27 of whom were randomized to attending physicians using the single-use device, and 25 of whom were randomized to attending physicians using the 2 reusable devices. All procedures were completed laparoscopically as planned, and all patients were discharged within 23 hours. Three women in each group were not included in the analysis due to missing seconds for times, which left 46 women in the study. There was 1 intraoperative complication of a cystotomy during development of the bladder flap in the presence of stage 4 endometriosis. The median age of the 46 women was 39.5 years (Table 1). The median uterine weight was 140 g (interquartile range: 100–360 g). The left side (attending physician) device assignment was 24 women using the single-use device and 22 women using the 2 reusable devices; the right side (resident) device assignments were the converse. Paired analyses indicated that the median difference in uterine vessel desiccation and electrosurgical cutting time between the single-use side and the reusable side was
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almost 5 min less with the single-use device than with the reusable device (24.7; p , .001) (Table 2). If both sides of the operation were performed with the single-use device, the median operating room cost savings would be $884.92 from time alone, with a total intraoperative direct cost savings of $254.16 per case. Significantly lower median uterine vessel desiccation and electrosurgical cutting time were found in the single-use group compared with the reusable group for the attending physicians (8.7 min vs 12.5 min; p , .05) (Table 2). This would result in a median operating room cost savings from time alone of $715.46 for attending physicians, if the single-use device was used for the entire operation, and a total intraoperative direct cost savings of $84.70 per case. Significantly lower median uterine vessel desiccation and electrosurgical cutting time were found for the single-use group compared with the reusable group for the resident physicians (8.4 min vs 16.7 min; p , .001) (Table 2). This would result in a median operating room cost savings from time alone of $1562.72 for residents, if the single-use device was used for the entire operation, and a total intraoperative direct cost savings of $931.96 per case.
Table 2 Times and costs for single use and reusable device sides for 46 total laparoscopic hysterectomy patients Study parameters
Single usea (median)
Reusableb (median)
Uterine vessel desiccation and electrosurgical cutting time (min) Resident physicians 8.4 16.7 Attending physicians 8.7 12.5 Resident and attending physicians combined 8.4 14.6 Costs of single use and reusable devices per case Device cost $630.14 $12.00c d Cost of disposing a single-use device $0.11 d Force triad electrosurgical generator $0.51 $0.51 Cord cost for reusable devices d $2.70c Cleaning and packaging of reusable devices d $15.00 Total device cost $630.76 $30.21 Cost savings based on median operating room time difference ! 2e Resident physicians 2$1,562.72 d Attending physicians 2$715.46 d Resident and attending physicians combined 2$884.92 d Total cost savings with single use device (time savings-cost of single use device) Resident physicians 2$931.96 d Attending physicians 2$84.70 d Resident and attending physicians combined 2$254.16 d e
Single use–reusable (median difference)
p value
28.3 23.8 24.7
,.001 ,.05 ,.001
This estimate of cleaning and packaging reusable devices is provided by Munro [13]. The respective sample sizes for resident and attending physicians are n 5 22 and n 5 24. b The respective sample sizes for resident and attending physicians are n 5 24 and n 5 22. c The cost of the reusable device is $1200, and the cost of the cord for the reusable device is $270. Both have a theoretical 100-use lifetime. The respective costs of the reusable device and the cord per case are thus $12.00 and $2.70. d The total cost of disposing all equipment of this nature for an entire year per pound at St. Mary’s Health Center is $23,499.58/128,413 pounds 5 $0.18/pound. The weight of the single-use device is 270 g (0.6 lb). The disposal cost of the single-use device is thus (0.6 lb) ($0.18/lb) 5 $0.11. e The median difference of minutes per side of each case favoring the single-use device would be multiplied by 2 if both sides of the operation were performed with the singleuse device. At a cost of operating room time at St. Mary’s Health Center of $94.14/min, the cost savings with the single-use device would be 2 (median difference min) ($94.14/ min) 5 cost savings. a
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Discussion The American Association of Gynecologic Laparoscopists Position Statement regarding the route of hysterectomy for benign disease states that a vaginal or laparoscopic approach should be performed when possible, due to reduced morbidity and faster return to normal activities [14]. Furthermore, depending on the instrumentation used during a procedure, the institutional costs may be greater with laparoscopic than vaginal hysterectomy [14–16]. this issue of costs related to an individual procedure is complex, and is the sum of indirect and direct costs that vary between institutions. Direct costs refer to costs that accumulate due to the performance of a procedure, such as surgical instrumentation, length of stay, operating room time, sutures, drapes, maintenance, and staff salaries [13]. Indirect costs refer to costs incurred by the patient, her family, or employer (e.g., lost wages or need for childcare) [14]. Our study attempted to look at the direct costs related to instrumentation. The indirect costs were theoretically the same because all procedures were completed laparoscopically. Our objective was to determine if we could justify the cost of a single-use device, through intraoperative time saved, compared with reusable devices during laparoscopic hysterectomy at a teaching center. Although many intraoperative direct costs were considered in the comparison, the cost effectiveness of the single-use device was largely determined through the saving of operating room time. We believed that the unique design of the patient serving as her own control could control for other factors that contribute to surgical difficulty (e.g., patient body habitus, previous surgery, presence of adhesive disease, and variable diagnosis). We recognized that the degree of difficulty might still vary between sides of a patient using this design, but that any such effects would likely be minimized through randomization. Previous studies randomized energy sources between patients, using either single-use or reusable instruments for an entire procedure for each patient, and subsequently compared operating times between patients. A recent study by Janssen et al [10] compared operating time and blood loss between patients randomized to either the LigaSure or reusable instruments during laparoscopic hysterectomy and found no significant differences between groups. There were limitations to this study because it was conducted in 3 hospitals, with variable experience among the primary surgeons. They attempted to control for variable surgical experience, uterine weight, and other confounding variables. However, this approach has limitations, because every patient’s hysterectomy will be different. Each patient will have a different degree of difficulty, based on size of the uterus, pathology present (fibroids or endometriosis), presence and extent of adhesive disease, body habitus, previous surgery, and other variables. These factors could affect surgical times. Unbiased comparisons of surgical times could
Journal of Minimally Invasive Gynecology, Vol 23, No 1, January 2016
only be achieved through control of these potential confounding variables through patient selection or statistical analysis. We recognized that even within an individual patient, the degree of surgical difficulty between sides of a laparoscopic hysterectomy could be different. There may never be a study design that can completely control for all anatomic differences. Finally, our hospital used the Force Triad electrosurgical unit for both the Ligasure and reusable devices, thus negating the capital and amortized costs of the electrosurgical unit in our study. Other medical centers that do not have this technology may need to consider different capital costs. Dr. Malcolm Munro addressed the complexities of the concept of cost in his comprehensive article, ‘‘Economics and Energy Sources’’ [13]. He noted that single-use surgical instrumentation might be cost effective if there is a significant time or risk reduction. He provided theoretical sample calculations in his article. The authors attempted to apply these factors to their calculations to assess a time reduction and to determine cost effectiveness with laparoscopic hysterectomy. The strengths of this study included its prospective design, adequate power, and randomization. This randomization more accurately controlled for differences of technical difficulty between cases and the experience of surgeons. A limitation of our study was that although surgeons were unaware of exact recorded times, neither the surgeons nor the staff recording times were blinded to the type of instruments used. We did not attempt to evaluate differences in risk reduction or safety between instruments. We did not evaluate the impact of time savings on the surgeon or anesthesiologist, and we recognized that the time savings were not likely enough to add an additional surgical case to the schedule. Although we observed that enough operative time was saved per case to actually translate to a cost savings per case by using a single-use device, our study was not a comprehensive cost analysis because it focused only on direct intraoperative costs. In addition, the cost of operating room time per minute varies between institutions, and therefore, might limit the generalization of our results. Further validation cost studies are needed. Our data demonstrated that the attending and resident physician times were very similar using the single-use device (8.7 min vs 8.4 min, respectively). Both attending and resident physicians demonstrated a significant time savings, and therefore, there were intraoperative direct cost savings using the single-use device for laparoscopic hysterectomy ($84.70 and $931.96, respectively). The time savings actually were beyond what was expected, particularly for the resident surgeon. It is possible that other single-use devices might also be cost effective, especially those that use the same generator as reusable devices, although further studies are needed for validation. This is particularly important and applicable to current practice during this time of limited budgets and demands to contain costs.
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Single-Use Energy Sources and Operating Room Time for Laparoscopic Hysterectomy: A Randomized Controlled Trial M. Brigid Holloran-Schwartz, MD*, Jeffrey A. Gavard, PhD, Jared C. Martin, MD, Robert J. Blaskiewicz, MD, and Patrick P. Yeung, Jr, MD From the Department of Obstetrics, Gynecology, and Women’s Health, Saint Louis University School of Medicine, Saint Louis, Missouri (all authors).
ABSTRACT Study Objectives: To compare the intraoperative direct costs of a single-use energy device with reusable energy devices during laparoscopic hysterectomy. Design: A randomized controlled trial (Canadian Task Force Classification I). Setting: An academic hospital. Patients: Forty-six women who underwent laparoscopic hysterectomy from March 2013 to September 2013. Interventions: Each patient served as her own control. One side of the uterine attachments was desiccated and transected with the single-use device (Ligasure 5-mm Blunt Tip LF1537 with the Force Triad generator). The other side was desiccated and transected with reusable bipolar forceps (RoBi 5 mm), and transected with monopolar scissors using the same Covidien Force Triad generator. The instrument approach used was randomized to the attending physician who was always on the patient’s left side. Resident physicians always operated on the patient’s right side and used the converse instruments of the attending physician. Measurements and Main Results: Start time was recorded at the utero-ovarian pedicle and end time was recorded after transection of the uterine artery on the same side. Costs included the single-use device; amortized costs of the generator, reusable instruments, and cords; cleaning and packaging of reusable instruments; and disposal of the single-use device. Operating room time was $94.14/min. We estimated that our single use-device cost $630.14 and had a total time savings of 6.7 min per case, or 3.35 min per side, which could justify the expense of the device. The single-use energy device had significant median time savings (24.7 min per side, p , .001) and total intraoperative direct cost savings ($254.16 per case). Conclusions: A single-use energy device that both desiccates and cuts significantly reduced operating room time to justify its own cost, and it also reduced total intraoperative direct costs during laparoscopic hysterectomy in our institution. Operating room cost per minute varies between institutions and must be considered before generalizing our results. Journal of Minimally Invasive Gynecology (2016) 23, 72–77 Ó 2016 AAGL. All rights reserved. Keywords:
DISCUSS
Costs; Laparoscopic hysterectomy; Operating room time; Reusable energy devices; Single-use energy device
You can discuss this article with its authors and with other AAGL members at http:// www.AAGL.org/jmig-22-6-JMIG-D-14-00562.
Use your Smartphone to scan this QR code and connect to the discussion forum for this article now* * Download a free QR Code scanner by searching for ‘‘QR scanner’’ in your smartphone’s app store or app marketplace.
Presented at the 2013 Global Congress of the American Association of Gynecologic Laparoscopists, November 11–14, 2013, Washington, D.C. Corresponding author: M. Brigid Holloran-Schwartz, MD, Department of Obstetrics, Gynecology, and Women’s Health, Saint Louis University School of Medicine, 6420 Clayton Road, Suite 230, Saint Louis, MO 63117. E-mail: [email protected] Submitted November 10, 2014. Accepted for publication August 19, 2015. Available at www.sciencedirect.com and www.jmig.org 1553-4650/$ - see front matter Ó 2016 AAGL. All rights reserved. http://dx.doi.org/10.1016/j.jmig.2015.08.881
Single-use bipolar radiofrequency hybrid devices are available that can both desiccate and cut vascular tissue during surgery with an integrated mechanical knife, but these devices add costs to the procedure. The Ligasure 5-mm Blunt Tip LF1537 (Covidien, Dublin, Ireland) desiccates tissue with impedance feedback using the Force Triad Generator (Covidien, Dublin, Ireland) and cuts using an integrated mechanical knife. With this device, an audible signal denotes when impedance rises to a level that suggests complete
Holloran-Schwartz et al.
Single-Use Energy Source and Operating Time
desiccation of the tissue between the 2 electrodes embedded in each jaw of the device; this creates a seal that can withstand 3 times the normal systolic blood pressure [1–3]. Several studies in the gastrointestinal literature that used a variety of Ligasure models have demonstrated a decrease in operating room time and/or blood loss compared with instruments that use ultrasonic or conventional radiofrequency energy [4–8]. A variety of Ligasure models have also been described for use in vaginal and laparoscopic hysterectomies [9–12]. Costs that should be considered when using a single-use radiofrequency device for a laparoscopic hysterectomy would be the purchase price of the single unit, the capital and amortized cost of the electrosurgical generator needed, and the cost of disposing of the instrument. Although some facilities ‘‘refurbish’’ these devices, this study focused on the cost as a single-use device. Alternatively, at our hospital, if a reusable approach is chosen to perform a laparoscopic hysterectomy, a 5-mm Rotating Bipolar Forcep (RoBi; Karl Storz, Tuttlingen, Germany) is available that can desiccate vascular tissue, and a reusable 5-mm monopolar scissor (model 34425 mA, Karl Storz) that can transect tissue is also available. Costs that should be considered when using reusable instruments are the capital and amortized costs of the instruments, with cords, repairs, and cleaning, and processing during its theoretical 100-use lifetime, as well as the capital and amortized costs of the electrosurgical generator needed. The purpose of this study was to determine if a single-use device that desiccates and cuts tissue during laparoscopic hysterectomy at an academic institution with resident physicians as first assistants could reduce operating room time and costs enough to justify its expense, when these and other intraoperative direct costs were compared between singleuse and reusable devices. Materials and Methods This study was approved by the Institutional Review Board of both St. Louis University and St. Mary’s Health Center. All women ages 18 years or older who presented for laparoscopic hysterectomy from March 2013 to September 2013 were asked to participate. They gave written consent to 1 of the 2 attending physicians (MBHS and PY) on the day of surgery. Both attending physicians have performed .500 laparoscopic hysterectomies. Exclusion criteria included age younger than 18 years, suspected malignancy, or if the first assistant was another attending physician, surgical assistant, or fellow. Inclusion criteria required a resident physician to be the first assistant. We chose a unique study design in which each patient could serve as her own control, and the energy source used on each side of the uterus was randomized. We used the Ligasure 5-mm Blunt Tip LF1537, using the Force Triad Electrosurgical Generator (software version 3.5 on a 2-bar standard setting that was never adjusted) to desiccate and transect 1 ‘‘side’’ of the uterine attachments. For each
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pedicle, including the uterine artery that was secured at the level of the internal os, 2 applications using the Ligasure were applied before transecting with the mechanical blade. Two reusable devices were used to desiccate and transect the other side. The reusable RoBi 5-mm Forceps were used to desiccate tissue using the same Force Triad Electrosurgical Generator at a standard setting of 35 W for bipolar coagulation. The attending physician subjectively assessed if desiccation had been achieved by visual and tactile feedback. The reusable 5-mm monopolar scissors (model 34425 mA, Karl Storz), which is standard for any laparoscopic tray at our hospital, was used to transect tissues using the Force Triad Electrosurgical Generator, with a cutting current of 30 W. The uterine artery was always secured and transected at the level of the internal os. The attending physician always operated on the left side of the patient, and the resident operated on the right. The resident always completed their side first. We hoped that patients serving as their own controls would help control for other patient specific characteristics that could contribute to surgical difficulty (e.g., body mass index, uterine size, uterine shape, adhesions, and mobility). Once consent was obtained before the start of the procedure, a blank, sealed, opaque envelope with paper inserts was randomly chosen after shuffling a container that held all of the envelopes. These sealed envelopes were kept in a locked office with the 30 inserts designated ‘‘reusable’’ and 30 inserts designated ‘‘disposable’’ (for the single-use device). If the insert with disposable was chosen, the attending physician used the single-use device. If the reusable insert was chosen, the attending physician used the reusable instrument approach. At the start of the procedure, adhesiolysis was performed, and the anatomy was normalized when needed before the start of the hysterectomy and recording of the times of the procedure. A side was defined as desiccation and transection of all upper pedicles, starting with the utero-ovarian (start time), fallopian tube and round ligament, to the final transection of the uterine artery (stop time). Adnexa were removed after the hysterectomy when indicated; these were not included in our analysis. The anterior leaf of the broad ligament was reflected inferiorly on each side using the designated energy source only to skeletonize the uterine vessels and safely displace the bladder. The full development of the bladder flap was not recorded in either side time, because the stopwatch was stopped and restarted when this plane needed to be developed to protect the bladder. Time was recorded in seconds by a medical student or circulating nurse, and was not discussed with the surgeons during the procedure. Colpotomy time was not included in the analysis. Data were entered into a database by a resident physician (JM) and validated by the statistician (JG). We considered the following costs of the single-use device (the Ligasure 5-mm Blunt Tip): the purchase price of the device ($630); the amortized cost of the Force Triad generator (software version 3.5); and the disposal fee of
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the device. The capital cost of the generator was $34,000, with the cost per case estimated to be $0.51. This was calculated by taking the original cost, dividing it by 10 years of use, and estimating that 90% of the surgical cases done in the hospital would use the generator. In our hospital, we use the same generator for the reusable approach, thus negating this cost. The disposal cost was estimated based on the total cost of disposing equipment at St. Mary’s Health Center for an entire year per pound converted to grams. The weight of the single-use device is 270 g, with a disposal cost of $0.11. We recognized, but did not calculate, the burden to the environment this additional waste would add. Costs that were considered with the reusable device, the RoBi Forceps included the amortized costs of the device and associated cord. The capital cost of the RoBi Forceps was $1200, with an additional cost of $270 for the cord. Both have a theoretical 100-use lifetime. The respective amortized costs of the RoBi and the cord thus were $12.00 and $2.70. Again, the same Force Triad generator was used for both arms of the study at a cost of $0.51/case. The reusable scissors used for transection and colpotomy are standard for any laparoscopic tray at our facility. They were required for the completion of the hysterectomy using this technique, regardless of which coagulation device was used, and therefore, they were not included in our analysis. Our hospital was unable to provide us with a cost for cleaning and repackaging reusable instruments; we therefore used an estimation from ‘‘Economics and Energy Sources,’’ by Munro of $15.00 [13]. The sample size was determined by estimating the mean time for vessel sealing and cutting (including an uncomplicated bladder flap), which was 20 min for both sides, with 70% of all cases being completed within 35 min (62 SDs). We considered our major costs to be the cost of the single-use device of $630.14 and operating room time of $94.14/min. The $94.14/min included support staff salaries, drapes, room maintenance, and use of the nonchargeable items (e.g., blankets, and so on). Costs did not include the professional fees of the surgeon or anesthesia staff. A time savings of 3.35 min per side with the single-use device at an a level of 0.05 and a level of power of 0.80 required a sample size of 45 women. Continuous variables were expressed as medians and ranges due to the lack of normality of the distributions. Categorical variables were expressed as numbers and percentages. Differences in uterine vessel desiccation and electrosurgical cutting time between single-use and reusable devices within patients were compared using the Wilcoxon signed rank test. Differences in uterine vessel desiccation and electrosurgical cutting time were compared between single-use and reusable devices for attending physicians and residents separately by using the independent Student’s t test for data, were normally distributed. The KolmogorovSmirnov test was used for data that were not normally distributed. Total single-use and reusable device intraoperative direct costs per case were estimated through itemized
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Fig. 1 Flow of participants through the study.
costs for the device, disposal, the generator, cord, cleaning and packaging, and operating room time differential. A p value of , .05 was used to denote statistical significance. All analyses were performed using SPSS (version 19.0 for Windows, IBM, Armonk, New York).
Table 1 Patient characteristics and operation data for 46 total laparoscopic hysterectomy patients Characteristic
All patients (N 5 46)
Age, yr 39.5 (34.0–46.5) 29.4 (24.0–36.9) BMI, kg/m2 Smoking, n (%) 11 (23.9) Chronic hypertension, n (%) 6 (13.0) Diabetes (any type), n (%) 2 (4.3) Gravidity 2 (0–3) Parity 1.0 (0–2.3) Uterine weight, gm 140 (100–360) Fibroids, n (%) 24 (52.2) Complications,a n (%) 1 (2.2) Estimated blood loss (mL) 75 (50–100) Morcellation, n (%) 15 (32.6) Left side (attending physician) device assignment Single use, n (%) 24 (52.2) Reusable, n (%) 22 (47.8) Left side uterine vessel desiccation and 11.4 (7.6–15.6) electrosurgical cutting time, min Right side (resident) device assignment Single use, n (%) 22 (47.8) Reusable, n (%) 24 (52.2) Right side uterine vessel desiccation and 10.1 (7.7–19.9) electrosurgical cutting time, min Total case time, min, median (IQR) 129 (101–167) BMI 5 body mass index. Data are median (interquartile [IQR]), unless noted otherwise. Uterine weight was unknown for 1 woman, and total case time was unknown for 10 women. a Cystotomy occurred in 1 woman.
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Results The flow of participants through the study is shown in Fig. 1. Fifty-two women gave informed consent, 27 of whom were randomized to attending physicians using the single-use device, and 25 of whom were randomized to attending physicians using the 2 reusable devices. All procedures were completed laparoscopically as planned, and all patients were discharged within 23 hours. Three women in each group were not included in the analysis due to missing seconds for times, which left 46 women in the study. There was 1 intraoperative complication of a cystotomy during development of the bladder flap in the presence of stage 4 endometriosis. The median age of the 46 women was 39.5 years (Table 1). The median uterine weight was 140 g (interquartile range: 100–360 g). The left side (attending physician) device assignment was 24 women using the single-use device and 22 women using the 2 reusable devices; the right side (resident) device assignments were the converse. Paired analyses indicated that the median difference in uterine vessel desiccation and electrosurgical cutting time between the single-use side and the reusable side was
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almost 5 min less with the single-use device than with the reusable device (24.7; p , .001) (Table 2). If both sides of the operation were performed with the single-use device, the median operating room cost savings would be $884.92 from time alone, with a total intraoperative direct cost savings of $254.16 per case. Significantly lower median uterine vessel desiccation and electrosurgical cutting time were found in the single-use group compared with the reusable group for the attending physicians (8.7 min vs 12.5 min; p , .05) (Table 2). This would result in a median operating room cost savings from time alone of $715.46 for attending physicians, if the single-use device was used for the entire operation, and a total intraoperative direct cost savings of $84.70 per case. Significantly lower median uterine vessel desiccation and electrosurgical cutting time were found for the single-use group compared with the reusable group for the resident physicians (8.4 min vs 16.7 min; p , .001) (Table 2). This would result in a median operating room cost savings from time alone of $1562.72 for residents, if the single-use device was used for the entire operation, and a total intraoperative direct cost savings of $931.96 per case.
Table 2 Times and costs for single use and reusable device sides for 46 total laparoscopic hysterectomy patients Study parameters
Single usea (median)
Reusableb (median)
Uterine vessel desiccation and electrosurgical cutting time (min) Resident physicians 8.4 16.7 Attending physicians 8.7 12.5 Resident and attending physicians combined 8.4 14.6 Costs of single use and reusable devices per case Device cost $630.14 $12.00c d Cost of disposing a single-use device $0.11 d Force triad electrosurgical generator $0.51 $0.51 Cord cost for reusable devices d $2.70c Cleaning and packaging of reusable devices d $15.00 Total device cost $630.76 $30.21 Cost savings based on median operating room time difference ! 2e Resident physicians 2$1,562.72 d Attending physicians 2$715.46 d Resident and attending physicians combined 2$884.92 d Total cost savings with single use device (time savings-cost of single use device) Resident physicians 2$931.96 d Attending physicians 2$84.70 d Resident and attending physicians combined 2$254.16 d e
Single use–reusable (median difference)
p value
28.3 23.8 24.7
,.001 ,.05 ,.001
This estimate of cleaning and packaging reusable devices is provided by Munro [13]. The respective sample sizes for resident and attending physicians are n 5 22 and n 5 24. b The respective sample sizes for resident and attending physicians are n 5 24 and n 5 22. c The cost of the reusable device is $1200, and the cost of the cord for the reusable device is $270. Both have a theoretical 100-use lifetime. The respective costs of the reusable device and the cord per case are thus $12.00 and $2.70. d The total cost of disposing all equipment of this nature for an entire year per pound at St. Mary’s Health Center is $23,499.58/128,413 pounds 5 $0.18/pound. The weight of the single-use device is 270 g (0.6 lb). The disposal cost of the single-use device is thus (0.6 lb) ($0.18/lb) 5 $0.11. e The median difference of minutes per side of each case favoring the single-use device would be multiplied by 2 if both sides of the operation were performed with the singleuse device. At a cost of operating room time at St. Mary’s Health Center of $94.14/min, the cost savings with the single-use device would be 2 (median difference min) ($94.14/ min) 5 cost savings. a
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Discussion The American Association of Gynecologic Laparoscopists Position Statement regarding the route of hysterectomy for benign disease states that a vaginal or laparoscopic approach should be performed when possible, due to reduced morbidity and faster return to normal activities [14]. Furthermore, depending on the instrumentation used during a procedure, the institutional costs may be greater with laparoscopic than vaginal hysterectomy [14–16]. this issue of costs related to an individual procedure is complex, and is the sum of indirect and direct costs that vary between institutions. Direct costs refer to costs that accumulate due to the performance of a procedure, such as surgical instrumentation, length of stay, operating room time, sutures, drapes, maintenance, and staff salaries [13]. Indirect costs refer to costs incurred by the patient, her family, or employer (e.g., lost wages or need for childcare) [14]. Our study attempted to look at the direct costs related to instrumentation. The indirect costs were theoretically the same because all procedures were completed laparoscopically. Our objective was to determine if we could justify the cost of a single-use device, through intraoperative time saved, compared with reusable devices during laparoscopic hysterectomy at a teaching center. Although many intraoperative direct costs were considered in the comparison, the cost effectiveness of the single-use device was largely determined through the saving of operating room time. We believed that the unique design of the patient serving as her own control could control for other factors that contribute to surgical difficulty (e.g., patient body habitus, previous surgery, presence of adhesive disease, and variable diagnosis). We recognized that the degree of difficulty might still vary between sides of a patient using this design, but that any such effects would likely be minimized through randomization. Previous studies randomized energy sources between patients, using either single-use or reusable instruments for an entire procedure for each patient, and subsequently compared operating times between patients. A recent study by Janssen et al [10] compared operating time and blood loss between patients randomized to either the LigaSure or reusable instruments during laparoscopic hysterectomy and found no significant differences between groups. There were limitations to this study because it was conducted in 3 hospitals, with variable experience among the primary surgeons. They attempted to control for variable surgical experience, uterine weight, and other confounding variables. However, this approach has limitations, because every patient’s hysterectomy will be different. Each patient will have a different degree of difficulty, based on size of the uterus, pathology present (fibroids or endometriosis), presence and extent of adhesive disease, body habitus, previous surgery, and other variables. These factors could affect surgical times. Unbiased comparisons of surgical times could
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only be achieved through control of these potential confounding variables through patient selection or statistical analysis. We recognized that even within an individual patient, the degree of surgical difficulty between sides of a laparoscopic hysterectomy could be different. There may never be a study design that can completely control for all anatomic differences. Finally, our hospital used the Force Triad electrosurgical unit for both the Ligasure and reusable devices, thus negating the capital and amortized costs of the electrosurgical unit in our study. Other medical centers that do not have this technology may need to consider different capital costs. Dr. Malcolm Munro addressed the complexities of the concept of cost in his comprehensive article, ‘‘Economics and Energy Sources’’ [13]. He noted that single-use surgical instrumentation might be cost effective if there is a significant time or risk reduction. He provided theoretical sample calculations in his article. The authors attempted to apply these factors to their calculations to assess a time reduction and to determine cost effectiveness with laparoscopic hysterectomy. The strengths of this study included its prospective design, adequate power, and randomization. This randomization more accurately controlled for differences of technical difficulty between cases and the experience of surgeons. A limitation of our study was that although surgeons were unaware of exact recorded times, neither the surgeons nor the staff recording times were blinded to the type of instruments used. We did not attempt to evaluate differences in risk reduction or safety between instruments. We did not evaluate the impact of time savings on the surgeon or anesthesiologist, and we recognized that the time savings were not likely enough to add an additional surgical case to the schedule. Although we observed that enough operative time was saved per case to actually translate to a cost savings per case by using a single-use device, our study was not a comprehensive cost analysis because it focused only on direct intraoperative costs. In addition, the cost of operating room time per minute varies between institutions, and therefore, might limit the generalization of our results. Further validation cost studies are needed. Our data demonstrated that the attending and resident physician times were very similar using the single-use device (8.7 min vs 8.4 min, respectively). Both attending and resident physicians demonstrated a significant time savings, and therefore, there were intraoperative direct cost savings using the single-use device for laparoscopic hysterectomy ($84.70 and $931.96, respectively). The time savings actually were beyond what was expected, particularly for the resident surgeon. It is possible that other single-use devices might also be cost effective, especially those that use the same generator as reusable devices, although further studies are needed for validation. This is particularly important and applicable to current practice during this time of limited budgets and demands to contain costs.
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