Surg Endosc DOI 10.1007/s00464-014-3497-7
and Other Interventional Techniques
FLS tasks can be used as an ergonomic discriminator between laparoscopic and robotic surgery Ahmed M. Zihni • Ikechukwu Ohu • Jaime A. Cavallo • Jenny Ousley • Sohyung Cho Michael M. Awad
•
Received: 3 October 2013 / Accepted: 17 February 2014 Ó Springer Science+Business Media New York 2014
Abstract Introduction Robotic surgery may result in ergonomic benefits to surgeons. In this pilot study, we utilize surface electromyography (sEMG) to describe a method for identifying ergonomic differences between laparoscopic and robotic platforms using validated Fundamentals of Laparoscopic Surgery (FLS) tasks. We hypothesize that FLS task performance on laparoscopic and robotic surgical platforms will produce significant differences in mean muscle activation, as quantified by sEMG. Methods Six right-hand-dominant subjects with varying experience performed FLS peg transfer (PT), pattern cutting (PC), and intracorporeal suturing (IS) tasks on laparoscopic and robotic platforms. sEMG measurements were obtained from each subject’s bilateral bicep, tricep, deltoid, and trapezius muscles. EMG measurements were normalized to the maximum voluntary contraction (MVC) of each muscle of each subject. Subjects repeated each task three times per platform, and mean values used for pooled analysis. Average normalized muscle activation (%MVC) was calculated for each muscle group in all subjects for each FLS task. We compared mean %MVC values with paired
A. M. Zihni (&) J. A. Cavallo M. M. Awad Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA e-mail: [email protected] I. Ohu S. Cho Department of Industrial and Manufacturing Engineering, Southern Illinois University at Edwardsville, Edwardsville, IL, USA J. Ousley Meharry Medical College, Nashville, TN, USA
t tests and considered differences with a p value less than 0.05 to be statistically significant. Results Mean activation of right bicep (2.7 %MVC lap, 1.3 %MVC robotic, p = 0.019) and right deltoid muscles (2.4 %MVC lap, 1.0 %MVC robotic, p = 0.019) were significantly elevated during the laparoscopic compared to the robotic IS task. The mean activation of the right trapezius muscle was significantly elevated during robotic compared to the laparoscopic PT (1.6 %MVC lap, 3.5 %MVC robotic, p = 0.040) and PC (1.3 %MVC lap, 3.6 %MVC robotic, p = 0.0018) tasks. Conclusions FLS tasks are validated, readily available instruments that are feasible for use in demonstrating ergonomic differences between surgical platforms. In this study, we used FLS tasks to compare mean muscle activation of four muscle groups during laparoscopic and robotic task performance. FLS tasks can serve as the basis for larger studies to further describe ergonomic differences between laparoscopic and robotic surgery. Keywords Ergonomics Robot-assisted laparoscopic surgery Laparoscopic surgery Fundamentals of laparoscopic surgery Human factors Simulation Laparoscopic surgery has offered several benefits to patients. Laparoscopic approaches result in shorter hospitalizations [1], less post-operative pain [2], and lower complication rates [3] when compared to open surgical approaches. For surgeons, however, laparoscopic procedures are often associated with greater ergonomic stress. In a recent survey of laparoscopic surgeons, 73 % reported physical complaints of neck, lower back, shoulder, and thumb pain during or after performing laparoscopic procedures [4]. Park et al. [5] reported that as many as 87 % of
123
Surg Endosc
laparoscopic surgeons experienced musculoskeletal symptoms and discomfort, and that this was independent of number of years in practice. Rather, these symptoms correlated with increased case loads, suggesting fatigue as an associated factor. Frequently cited limitations of conventional laparoscopic surgery include suboptimal design of instrument handles, poor table height adjustment, and bad monitor positioning [6–9]. By design, robotic surgical systems have the potential to overcome each of these limitations. In fact, several authors have described improvements in physical stress while performing procedures with the da Vinci Surgical SystemÒ (dVSS) (Intuitive Surgical, Incorporated; Sunnyvale, CA) [10–12]. However, to date most of these descriptions have been subjective and qualitative in nature [13–15]. Our group seeks to describe the potential differences in ergonomic stress between conventional laparoscopy and the dVSS. Measurement of ergonomic performance is a wellstudied discipline and has been described in a wide variety of industrial fields [16, 17]. The field of surgical ergonomics is a rapidly developing one, sparked in large part by the emergence of laparoscopy and the recognition of associated occupational injuries [18]. There are several well-described methods of measuring ergonomic stress including motion analysis, force plate systems, and electromyography (EMG). Of these, EMG is perhaps the best suited to measure the fatigue and musculoskeletal discomfort experienced during laparoscopic procedures, as it involves direct data collection from the impacted muscles. During surface EMG (sEMG), electrodes with built-in amplifiers are attached to the skin over target muscles. The advantage of sEMG is that it is a simple, noninvasive way to quantify muscle fatigue and force with high reliability. As such, it has become a validated and widely adopted tool for measuring physical workload and fatigue [19]. In order to perform studies of surgical ergonomics, we sought to identify tasks that could be performed by surgeons in a dry-lab setting using both laparoscopic and robotic surgical platforms. The ideal tasks for this purpose should be validated, easily accessible and reproducible, amenable to repeated trials, applicable to both surgical platforms, low cost, widely familiar to surgeons from varying specialties, and simple enough that participants with varying levels of surgical training could be expected to complete them. The fundamentals of laparoscopic surgery (FLS), a didactic and surgical skills examination jointly developed by the American College of Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons, includes tasks that have the potential to meet all of these criteria [20]. In particular, the peg transfer (PT), pattern cutting (PC), and intracorporeal suturing (IS) tasks are appropriate for both platforms. FLS tasks are validated, and a broad body of literature exists examining
123
their use in surgical education [20]. Completion of the FLS examination is now a pre-requisite for certification of completion of residency training in general surgery, and FLS skills training has been widely adopted in other surgical disciplines as well [21, 22]. The use of FLS tasks to study comparative surgical ergonomics is less widely studied, however, similar dry-lab tasks have been used to identify ergonomic differences between open and laparoscopic surgical platforms [7]. Berguer et al. [23] used tasks similar to FLS tasks (glove suturing, pin transfer) to compare dominant-arm sEMG data during robotic and laparoscopic task performance. They noted significantly lower dominant-arm thenar activation, but no significant differences in deltoid or forearm activation. These findings suggest a role for dry-lab tasks such as FLS tasks in comparing the ergonomics of robotic and laparoscopic surgery. The Berguer study used the ZEUS robotic surgical system (Computer Motion, Inc., Goleta, CA) which has been discontinued and is distinct from the dVSS, evaluated activation of muscles only in the dominant arm, and did not evaluate the bicep or tricep muscle groups. More recent studies have examined surgical ergonomics of laparoscopic and dVSS platforms using various experimental models [24]. To date, however, there have been no evaluations of the discriminatory power of FLS tasks as an experimental model in studies of surgical ergonomics. In this pilot study, we sought to evaluate the use of FLS tasks to identify ergonomic differences between laparoscopic and robotic surgical task performance in bilateral bicep, tricep, deltoid, and trapezius muscle groups, as quantified by sEMG data. We hypothesize that in subjects of varying levels of surgical experience, statistically significant differences in muscle activation will be noted between the laparoscopic and robotic platforms. In addition, we further hypothesize that there will be a statistically significant increase in muscle activation when performing more technically challenging FLS tasks, such as IS when compared to simpler tasks such as PT and PC. We expect these differences to be mitigated on the robotic platform compared to the laparoscopic platform.
Methods Subject recruitment Under an IRB-approved protocol, six subjects participated in this pilot study at Washington University in St Louis. Two attending surgeons participated, both of whom were expert laparoscopists (greater than 100 laparoscopic cases) and one of whom was an expert robotic surgeon (greater than 50 robotic cases) as well. Two mid-level surgical residents with laparoscopic experience but no robotic
Surg Endosc
experience, and two surgical novices naive to both the laparoscopic and robotic platforms were also recruited. All subjects were right-hand dominant. The study was performed in a lab equipped with a standard laparoscopic trainer setup including a laparoscopic trainer box (Karl Storz Endoscopy America, IncorporatedÒ; Culver City, CA) positioned on a table, a standard 10 mm 30-degree laparoscope (Karl Storz Endoscopy America, IncorporatedÒ), and laparoscopic instruments including needle drivers, graspers, and scissors. Subjects were instructed to stand in the position most comfortable for them, and step stools were available upon request. The lab was also equipped with a standard da Vinci Surgical SystemÒ (dVSS Intuitive Surgical, IncorporatedÒ; Sunnyvale, CA) attached to a trainer box and equipped with needle drivers, graspers, and scissors. A height-adjustable chair was provided for the dVSS platform. All subjects without robotic experience received a 20-min introductory session on operating the dVSS console before beginning the study. All subjects without significant laparoscopic experience received a 20-min introductory session before beginning the study. As this was an explorative pilot study, a poweranalysis was not carried out during the planning phase of this project. FLS tasks Each subject performed PT, PC, and IS tasks on the laparoscopic and robotic platforms in standard fashion according to FLS protocol [25]. PC, PT, and IS tasks were performed in that order on the laparoscopic platform, then the robotic platform. Subjects were allowed to rest for 10 min between platforms, mitigating the effect of fatigue on subsequent trials. Each subject performed three repetitions of each task on each platform while sEMG data was collected. Surface EMG All sEMG data were collected using an 8-channel BioradioÒ 150 physiologic data acquisition system (Great Lakes Neurotechnologies, IncorporatedÒ; Cleveland, OH). After wiping skin surfaces overlying target muscle groups with rubbing alcohol and allowing the alcohol to dry, two 100 9 100 MVAP-IIÒ electrodes (MVAP Medical Supplies, IncorporatedÒ; Newbury Park, CA) were placed over the muscle bellies of each muscle group and connected to the positive and negative input poles for each channel. The muscles tested were the bilateral bicep, tricep, deltoid, and trapezius muscles. An electrode was also attached to the right elbow and connected to the ground input on the BioradioÒ 150 to complete the input circuit.
The BiocaptureÒ data acquisition software package (Great Lakes Neurotechnologies, IncorporatedÒ; Cleveland, OH) was used to capture and filter sEMG data. sEMG data was captured at a sampling frequency of 256 Hz from each channel. Digital signal processing filters were applied to exclude low (\10 Hz) and high frequency ([127 Hz) signals at the time of data capture. We selected the bilateral bicep, tricep, deltoid, and trapezius muscle groups for analysis in this study. The bicep and tricep muscles are very active muscles of arm flexion and extension, two of the most common actions during laparoscopic and robotic surgery, and were therefore selected as indicators of overall muscle activation during task performance. In addition, these muscle groups were selected to provide continuity and reference points with other surgical ergonomics studies, in which their activation was studied [24]. Trapezius and deltoid muscles were selected because the shoulder and neck are among the most common sites of musculoskeletal symptoms in laparoscopic surgeons [4]. We sought to only assess muscle groups that could be studied using EMG in a dry-lab setting and also in subsequent studies in a live operating room setting. Intrinsic hand and forearm muscles were therefore excluded because EMG sensors cannot easily be sterilized during a surgical scrub. At the start of data collection, EMG data was collected individually from each muscle group while the maximal voluntary contraction (MVC) of that muscle was elicited by an assistant providing resistance. The MVC of the biceps were obtained by arm flexion against resistance, MVC of the triceps were obtained by arm extension against resistance, deltoid MVC data were obtained by abduction of a flexed arm against resistance, and MVC data from trapezius muscles were through a shoulder shrug against resistance. Subjects then performed FLS tasks while EMG data was being collected from the eight muscle groups. Three repetitions of each task were performed on each surgical platform. %MVC The primary outcome variable in this study was the %MVC, calculated in the standard manner for a study of this kind [18], as defined in the formula below: %MVC ¼
iEMG 100 %; MVC
where %MVC is the percentage of maximal voluntary contraction; iEMG is the rectified, processed, and integrated sEMG data for a particular muscle group during a task repetition; and MVC is the voltage generated by that muscle group during a maximal contraction. The %MVC value represents that percentage of maximal muscle effort
123
Surg Endosc
that is generated by task performance. We performed all analyses of raw sEMG data using the MATLABÒ numerical computing environment (MathWorks, IncorporatedÒ; Natick, MA).
significantly elevated during IS compared to both PT and PC (p = 0.0208, p = 0.0269, respectively). No other significant differences are noted. When comparing the FLS tasks to one another on the robotic platform, no significant difference in %MVC is seen in any muscle group.
Data analysis After performing each FLS task three times on a platform, a mean %MVC value was computed for each muscle group of the subject during a given task. Mean %MVC data was calculated for the full group. Mean %MVC values generated by laparoscopic and robotic task performance of each FLS task were compared using two-sided paired t tests. Data obtained from an individual subject on the laparoscopic platform was paired to data from the same subject on the robotic platform. A p value of\0.05 was considered the threshold of statistical significance. To compare FLS tasks to one another, we used ANOVA to perform a comparison of mean %MVC generated by the three FLS tasks in each muscle group. This analysis was performed separately on data derived from each surgical platform. An F statistic corresponding to a probability \0.05 was used as the threshold of statistical significance. Any muscle groups where a significant difference were further analyzed with pairwise comparisons of mean %MVC of each of the three FLS tasks to the other two tasks using two-sided paired t tests. A p value of\0.05 was considered the threshold of statistical significance.
Results Statistically significant differences in muscle activation between the laparoscopic and robotic platforms were noted for at least one muscle group during each FLS task (Fig. 1). Significantly increased right trapezius activation occurred during the robotic compared to the laparoscopic PT task (1.6 %MVC laparoscopic, 3.5 %MVC robotic, p = 0.0400). Significantly increased right trapezius activation occurred during the robotic compared to the laparoscopic PC task (1.3 %MVC laparoscopic, 3.6 %MVC robotic, p = 0.0018). Significantly increased right bicep muscle activation (2.7 %MVC laparoscopic, 1.3 %MVC robotic, p = 0.0190) and right deltoid muscle activation (2.4 %MVC laparoscopic, 1.0 %MVC robotic, p = 0.0190) occurred during the laparoscopic compared to the robotic IS task. When comparing the FLS tasks to one another on the laparoscopic platform (Fig. 2), a significant difference in mean muscle activation is seen in the right trapezius muscle group when comparing the three tasks (PT: 1.6 %MVC, PC: 1.3 %MVC, IS: 3.7 % MVC, F stat. 4.171, Sig. 0.036). Pairwise comparisons revealed that %MVC was
123
Discussion In this study, we describe the use of FLS tasks to study the comparative ergonomics of the laparoscopic and robotic surgical platforms. In our pilot sample with subjects representing varying levels of surgical training and experience, we have shown that the FLS PT, PC, and IS tasks can identify statistically significant differences in muscle activation during laparoscopic and robotic task performance. As expected, more significant differences were seen with the IS task, the most challenging FLS task performed in this study. In addition, all statistically significant differences were seen in muscle groups of the right upper extremity, the side of upper extremity dominance for all of the participating subjects. This may be due to greater exertion during task performance. Our data suggest that laparoscopic task performance may lead to increased activation of the right bicep and deltoid muscles, while robotic task performance may lead to increased right trapezius muscle activation in right-hand dominant individuals. Further study with a larger study population will be required to confirm these findings. The data show that when it comes to robotic task performance, we did not detect any ergonomic difference between PT, PC, and IS tasks. However, significant differences are demonstrated in FLS task performance on the laparoscopic platform. These findings suggest that ergonomic differences may exist between the FLS tasks, and inform future studies using this experimental model. Where differences were detected, the more complex IS task was associated with higher levels of muscle activation than simpler PT and PC tasks, suggesting that more difficult tasks may be associated with higher levels of ergonomic strain. Larger studies are needed to quantify the extent of the interaction between task difficulty and ergonomic strain. In addition, these findings suggest that the robotic platform may play some role in ‘‘equalizing’’ the ergonomic profile of simpler and more challenging FLS tasks. In summary, we have described the use of FLS tasks as an experimental model for studying comparative ergonomics of the laparoscopic and robotic surgical platforms. Further studies using this model will elaborate and expand upon the ergonomic differences identified in this study. As a pilot study, the small sample size limits the generalizability of our ergonomic findings to the general population of surgeons, and limits any subgroup analyses we could
Surg Endosc Fig. 1 Muscle activation during FLS task performance on laparoscopic and robotic platforms. *p \ 0.05
123
Surg Endosc Fig. 2 Comparative ergonomics of FLS tasks. PT FLS peg transfer, PC FLS pattern cutting, IS FLS intracorporeal suturing. *F stat. 4.171, Sig. 0.036
perform. We intend to use this model to study the effects, if any, that age, gender, hand-dominance, and surgical experience may have on the comparative ergonomic stress of the laparoscopic and robotic surgical platforms. In addition, while a body of literature does exist correlating FLS performance and intra-operative performance [21], no such data exist for the use of FLS tasks to evaluate surgical ergonomics. Future studies must elucidate the relationship between intra-operative and FLS ergonomic profiles. Finally, the technical limitation of an eight-channel-wired EMG setup limited the scope of our data collection to four muscle groups bilaterally. Future study will be required to expand on these findings to include muscles of the low back, forearm, hand, and lower extremity. Ergonomic differences between FLS tasks seen in this study support the use of multiple tasks in future ergonomic studies. Aside from being capable of identifying ergonomic differences, FLS tasks are well known to the surgical community, as being reproducible, low cost, and amenable performance by individuals of various levels of surgical experience. Our findings confirm our hypothesis that significant differences in muscle activation can be identified using these tasks and further lend support to the use of FLS tasks as an appropriate experimental model for the study of surgical ergonomics.
Conclusions FLS tasks are validated, readily available instruments that are feasible for use in demonstrating ergonomic differences
123
between surgical platforms. In this study, we used FLS tasks to compare mean muscle activation of four muscle groups during laparoscopic and robotic task performance. FLS tasks can serve as the basis for larger studies to further describe ergonomic differences between laparoscopic and robotic surgery. Acknowledgments The authors thank Gyusung Lee, PhD of the Department of Surgery at Johns Hopkins University (Baltimore, MD) for his valuable advice. This study was supported by a research grant from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES), and also by a research grant from Intuitive Surgical, Inc. (Sunnyvale, CA). Disclosures Dr. Zihni has received research grant funding for unrelated studies from the National Institutes of Health. Dr. Cavallo has received research grant funding for unrelated studies from the National Institutes of Health, the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), and the American Hernia Society in collaboration with DavolÒ Incorporated; and has served as a one-time consultant for Guidepoint GlobalÒ Incorporated. Dr. Cho has received research grant funding from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES) and Intuitive, Surgical Inc. (Sunnyvale, CA). Dr. Awad has received research grant funding from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES) and Intuitive, Surgical Inc. (Sunnyvale, CA). Mr. Ohu and Ms. Ousley have no conflicts of interest or financial ties to disclose.
References 1. Bhogal RH, Athwal R, Durkin D, Deakin M, Cheruvu CN (2008) Comparison between open and laparoscopic repair of perforated peptic ulcer disease. World J Surg 32:2371–2374 2. Wilson CH, Sanni A, Rix DA, Soomro NA (2011) Laparoscopic versus open nephrectomy for live kidney donors. Cochrane Database Syst Rev. doi:10.1002/14651858.CD006124
Surg Endosc 3. Li MZ, Lian L, Xiao LB, Wu WH, He YL, Song XM (2012) Laparoscopic versus open adhesiolysis in patients with adhesive small bowel obstruction: a systematic review and meta-analysis. Am J Surg 204:779–786 4. Sari V, Nieboer TE, Vierhout ME, Stegeman DF, Kluivers KB (2010) The operation room as a hostile environment for surgeons: physical complaints during and after laparoscopy. Minim Invasive Ther Allied Technol 19:105–109 5. Park A, Lee G, Seagull FJ, Meenaghan N, Dexter D (2010) Patients benefit while surgeons suffer: an impending epidemic. J Am Coll Surg 210:306–313 6. Berguer R, Smith WD, Chung YH (2001) Performing laparoscopic surgery is significantly more stressful for the surgeon than open surgery. Surg Endosc 15:1204–1207 7. Berguer R, Chen J, Smith WD (2003) A comparison of the physical effort required for laparoscopic and open surgical techniques. Arch Surg 138:967–970 8. Lee G, Lee T, Dexter D, Godinez C, Meenaghan N, Catania R, Park A (2009) Ergonomic risk associated with assisting in minimally invasive surgery. Surg Endosc 23:182–188 9. Berguer R (1998) Surgical technology and the ergonomics of laparoscopic instruments. Surg Endosc 12:458–462 10. O’Sullivan OE, O’Reilly BA (2012) Robot-assisted surgery: impact on gynaecological and pelvic floor reconstructive surgery. Int Urogynecol J 23:1163–1173 11. Kumar P, Kommu SS, Challacombe BJ, Dasgup-Ta P (2010) Laparoendoscopic single-site surgery (LESS) prostatectomy– robotic and conventional approach. Minerva Urol Nefrol 62:425–430 12. Lunca S, Bouras G, Stanescu AC (2005) Gastrointestinal robotassisted surgery. A current perspective. Rom J Gastroenterol 14:385–391 13. Xia T, Baird C, Jallo G, Hayes K, Nakajima N, Hata N, Kazanzides P (2008) An integrated system for planning, navigation and robotic assistance for skull base surgery. Int J Med Robot 4:321–330 14. Frick AC, Falcone T (2009) Robotics in gynecologic surgery. Minerva Ginecol 61:187–199 15. Wright AS, Gould JC, Melvin WS (2004) Computer-assisted robotic antireflux surgery. Minerva Gastroenterol Dietol 50:253–260
16. Anton D, Gerr F, Meyers A, Cook TM, Rosecrance JC, Reynolds J (2007) Effect of aviation snip design and task height on upper extremity muscular activity and wrist posture. J Occup Environ Hyg 4:99–113 17. Jones T, Kumar S (2008) Comparison of ergonomic risk assessment output in a repetitive sawmill occupation: trim-saw operator. Work 31:367–376 18. Lee G, Lee T, Dexter D, Klein R, Park A (2007) Methodological infrastructure in surgical ergonomics: a review of tasks, models, and measurement systems. Surg Innov 14:153–167 19. Lofland KR, Mumby PB, Cassisi JE, Palumbo NL, Camic PM (1995) Assessment of lumbar EMG during static and dynamic activity in pain-free normals: implications for muscle scanning protocols. Biofeedback Self Regul 20:3–18 20. Edelman DA, Mattos MA, Bouwman DL (2012) Value of fundamentals of laparoscopic surgery training in a fourth-year medical school advanced surgical skills elective. J Surg Res 177:207–210 21. Antosh DD, Auguste T, George EA, Sokol AI, Gutman RE, Iglesia CB, Desale SY, Park AJ (2013) Blinded assessment of operative performance after fundamentals of laparoscopic surgery in gynecology training. J Minim Invasive Gynecol 20:353–359 22. Sweet RM, Beach R, Sainfort F, Gupta P, Reihsen T, Poniatowski LH, McDougall EM (2011) Introduction and validation of the American Urological Association Basic Laparoscopic Urologic Surgery skills curriculum. J Endourol 26:190–196 23. Berguer R, Smith W (2006) An ergonomic comparison of robotic and laparoscopic technique: the influence of surgeon experience and task complexity. J Surg Res 134:87–92 24. Lee GI, Lee MR, Clanton T, Sutton E, Park AE, Marohn MR (2013) Comparative assessment of physical and cognitive ergonomics associated with robotic and traditional laparoscopic surgeries. Surg Endosc 28:456–465 25. Vassiliou MC, Dunkin BJ, Marks JM, Fried GM (2010) FLS and FES: comprehensive models of training and assessment. Surg Clin N Am 90:535–558
123
and Other Interventional Techniques
FLS tasks can be used as an ergonomic discriminator between laparoscopic and robotic surgery Ahmed M. Zihni • Ikechukwu Ohu • Jaime A. Cavallo • Jenny Ousley • Sohyung Cho Michael M. Awad
•
Received: 3 October 2013 / Accepted: 17 February 2014 Ó Springer Science+Business Media New York 2014
Abstract Introduction Robotic surgery may result in ergonomic benefits to surgeons. In this pilot study, we utilize surface electromyography (sEMG) to describe a method for identifying ergonomic differences between laparoscopic and robotic platforms using validated Fundamentals of Laparoscopic Surgery (FLS) tasks. We hypothesize that FLS task performance on laparoscopic and robotic surgical platforms will produce significant differences in mean muscle activation, as quantified by sEMG. Methods Six right-hand-dominant subjects with varying experience performed FLS peg transfer (PT), pattern cutting (PC), and intracorporeal suturing (IS) tasks on laparoscopic and robotic platforms. sEMG measurements were obtained from each subject’s bilateral bicep, tricep, deltoid, and trapezius muscles. EMG measurements were normalized to the maximum voluntary contraction (MVC) of each muscle of each subject. Subjects repeated each task three times per platform, and mean values used for pooled analysis. Average normalized muscle activation (%MVC) was calculated for each muscle group in all subjects for each FLS task. We compared mean %MVC values with paired
A. M. Zihni (&) J. A. Cavallo M. M. Awad Department of Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8109, St. Louis, MO 63110, USA e-mail: [email protected] I. Ohu S. Cho Department of Industrial and Manufacturing Engineering, Southern Illinois University at Edwardsville, Edwardsville, IL, USA J. Ousley Meharry Medical College, Nashville, TN, USA
t tests and considered differences with a p value less than 0.05 to be statistically significant. Results Mean activation of right bicep (2.7 %MVC lap, 1.3 %MVC robotic, p = 0.019) and right deltoid muscles (2.4 %MVC lap, 1.0 %MVC robotic, p = 0.019) were significantly elevated during the laparoscopic compared to the robotic IS task. The mean activation of the right trapezius muscle was significantly elevated during robotic compared to the laparoscopic PT (1.6 %MVC lap, 3.5 %MVC robotic, p = 0.040) and PC (1.3 %MVC lap, 3.6 %MVC robotic, p = 0.0018) tasks. Conclusions FLS tasks are validated, readily available instruments that are feasible for use in demonstrating ergonomic differences between surgical platforms. In this study, we used FLS tasks to compare mean muscle activation of four muscle groups during laparoscopic and robotic task performance. FLS tasks can serve as the basis for larger studies to further describe ergonomic differences between laparoscopic and robotic surgery. Keywords Ergonomics Robot-assisted laparoscopic surgery Laparoscopic surgery Fundamentals of laparoscopic surgery Human factors Simulation Laparoscopic surgery has offered several benefits to patients. Laparoscopic approaches result in shorter hospitalizations [1], less post-operative pain [2], and lower complication rates [3] when compared to open surgical approaches. For surgeons, however, laparoscopic procedures are often associated with greater ergonomic stress. In a recent survey of laparoscopic surgeons, 73 % reported physical complaints of neck, lower back, shoulder, and thumb pain during or after performing laparoscopic procedures [4]. Park et al. [5] reported that as many as 87 % of
123
Surg Endosc
laparoscopic surgeons experienced musculoskeletal symptoms and discomfort, and that this was independent of number of years in practice. Rather, these symptoms correlated with increased case loads, suggesting fatigue as an associated factor. Frequently cited limitations of conventional laparoscopic surgery include suboptimal design of instrument handles, poor table height adjustment, and bad monitor positioning [6–9]. By design, robotic surgical systems have the potential to overcome each of these limitations. In fact, several authors have described improvements in physical stress while performing procedures with the da Vinci Surgical SystemÒ (dVSS) (Intuitive Surgical, Incorporated; Sunnyvale, CA) [10–12]. However, to date most of these descriptions have been subjective and qualitative in nature [13–15]. Our group seeks to describe the potential differences in ergonomic stress between conventional laparoscopy and the dVSS. Measurement of ergonomic performance is a wellstudied discipline and has been described in a wide variety of industrial fields [16, 17]. The field of surgical ergonomics is a rapidly developing one, sparked in large part by the emergence of laparoscopy and the recognition of associated occupational injuries [18]. There are several well-described methods of measuring ergonomic stress including motion analysis, force plate systems, and electromyography (EMG). Of these, EMG is perhaps the best suited to measure the fatigue and musculoskeletal discomfort experienced during laparoscopic procedures, as it involves direct data collection from the impacted muscles. During surface EMG (sEMG), electrodes with built-in amplifiers are attached to the skin over target muscles. The advantage of sEMG is that it is a simple, noninvasive way to quantify muscle fatigue and force with high reliability. As such, it has become a validated and widely adopted tool for measuring physical workload and fatigue [19]. In order to perform studies of surgical ergonomics, we sought to identify tasks that could be performed by surgeons in a dry-lab setting using both laparoscopic and robotic surgical platforms. The ideal tasks for this purpose should be validated, easily accessible and reproducible, amenable to repeated trials, applicable to both surgical platforms, low cost, widely familiar to surgeons from varying specialties, and simple enough that participants with varying levels of surgical training could be expected to complete them. The fundamentals of laparoscopic surgery (FLS), a didactic and surgical skills examination jointly developed by the American College of Surgeons and the Society of American Gastrointestinal and Endoscopic Surgeons, includes tasks that have the potential to meet all of these criteria [20]. In particular, the peg transfer (PT), pattern cutting (PC), and intracorporeal suturing (IS) tasks are appropriate for both platforms. FLS tasks are validated, and a broad body of literature exists examining
123
their use in surgical education [20]. Completion of the FLS examination is now a pre-requisite for certification of completion of residency training in general surgery, and FLS skills training has been widely adopted in other surgical disciplines as well [21, 22]. The use of FLS tasks to study comparative surgical ergonomics is less widely studied, however, similar dry-lab tasks have been used to identify ergonomic differences between open and laparoscopic surgical platforms [7]. Berguer et al. [23] used tasks similar to FLS tasks (glove suturing, pin transfer) to compare dominant-arm sEMG data during robotic and laparoscopic task performance. They noted significantly lower dominant-arm thenar activation, but no significant differences in deltoid or forearm activation. These findings suggest a role for dry-lab tasks such as FLS tasks in comparing the ergonomics of robotic and laparoscopic surgery. The Berguer study used the ZEUS robotic surgical system (Computer Motion, Inc., Goleta, CA) which has been discontinued and is distinct from the dVSS, evaluated activation of muscles only in the dominant arm, and did not evaluate the bicep or tricep muscle groups. More recent studies have examined surgical ergonomics of laparoscopic and dVSS platforms using various experimental models [24]. To date, however, there have been no evaluations of the discriminatory power of FLS tasks as an experimental model in studies of surgical ergonomics. In this pilot study, we sought to evaluate the use of FLS tasks to identify ergonomic differences between laparoscopic and robotic surgical task performance in bilateral bicep, tricep, deltoid, and trapezius muscle groups, as quantified by sEMG data. We hypothesize that in subjects of varying levels of surgical experience, statistically significant differences in muscle activation will be noted between the laparoscopic and robotic platforms. In addition, we further hypothesize that there will be a statistically significant increase in muscle activation when performing more technically challenging FLS tasks, such as IS when compared to simpler tasks such as PT and PC. We expect these differences to be mitigated on the robotic platform compared to the laparoscopic platform.
Methods Subject recruitment Under an IRB-approved protocol, six subjects participated in this pilot study at Washington University in St Louis. Two attending surgeons participated, both of whom were expert laparoscopists (greater than 100 laparoscopic cases) and one of whom was an expert robotic surgeon (greater than 50 robotic cases) as well. Two mid-level surgical residents with laparoscopic experience but no robotic
Surg Endosc
experience, and two surgical novices naive to both the laparoscopic and robotic platforms were also recruited. All subjects were right-hand dominant. The study was performed in a lab equipped with a standard laparoscopic trainer setup including a laparoscopic trainer box (Karl Storz Endoscopy America, IncorporatedÒ; Culver City, CA) positioned on a table, a standard 10 mm 30-degree laparoscope (Karl Storz Endoscopy America, IncorporatedÒ), and laparoscopic instruments including needle drivers, graspers, and scissors. Subjects were instructed to stand in the position most comfortable for them, and step stools were available upon request. The lab was also equipped with a standard da Vinci Surgical SystemÒ (dVSS Intuitive Surgical, IncorporatedÒ; Sunnyvale, CA) attached to a trainer box and equipped with needle drivers, graspers, and scissors. A height-adjustable chair was provided for the dVSS platform. All subjects without robotic experience received a 20-min introductory session on operating the dVSS console before beginning the study. All subjects without significant laparoscopic experience received a 20-min introductory session before beginning the study. As this was an explorative pilot study, a poweranalysis was not carried out during the planning phase of this project. FLS tasks Each subject performed PT, PC, and IS tasks on the laparoscopic and robotic platforms in standard fashion according to FLS protocol [25]. PC, PT, and IS tasks were performed in that order on the laparoscopic platform, then the robotic platform. Subjects were allowed to rest for 10 min between platforms, mitigating the effect of fatigue on subsequent trials. Each subject performed three repetitions of each task on each platform while sEMG data was collected. Surface EMG All sEMG data were collected using an 8-channel BioradioÒ 150 physiologic data acquisition system (Great Lakes Neurotechnologies, IncorporatedÒ; Cleveland, OH). After wiping skin surfaces overlying target muscle groups with rubbing alcohol and allowing the alcohol to dry, two 100 9 100 MVAP-IIÒ electrodes (MVAP Medical Supplies, IncorporatedÒ; Newbury Park, CA) were placed over the muscle bellies of each muscle group and connected to the positive and negative input poles for each channel. The muscles tested were the bilateral bicep, tricep, deltoid, and trapezius muscles. An electrode was also attached to the right elbow and connected to the ground input on the BioradioÒ 150 to complete the input circuit.
The BiocaptureÒ data acquisition software package (Great Lakes Neurotechnologies, IncorporatedÒ; Cleveland, OH) was used to capture and filter sEMG data. sEMG data was captured at a sampling frequency of 256 Hz from each channel. Digital signal processing filters were applied to exclude low (\10 Hz) and high frequency ([127 Hz) signals at the time of data capture. We selected the bilateral bicep, tricep, deltoid, and trapezius muscle groups for analysis in this study. The bicep and tricep muscles are very active muscles of arm flexion and extension, two of the most common actions during laparoscopic and robotic surgery, and were therefore selected as indicators of overall muscle activation during task performance. In addition, these muscle groups were selected to provide continuity and reference points with other surgical ergonomics studies, in which their activation was studied [24]. Trapezius and deltoid muscles were selected because the shoulder and neck are among the most common sites of musculoskeletal symptoms in laparoscopic surgeons [4]. We sought to only assess muscle groups that could be studied using EMG in a dry-lab setting and also in subsequent studies in a live operating room setting. Intrinsic hand and forearm muscles were therefore excluded because EMG sensors cannot easily be sterilized during a surgical scrub. At the start of data collection, EMG data was collected individually from each muscle group while the maximal voluntary contraction (MVC) of that muscle was elicited by an assistant providing resistance. The MVC of the biceps were obtained by arm flexion against resistance, MVC of the triceps were obtained by arm extension against resistance, deltoid MVC data were obtained by abduction of a flexed arm against resistance, and MVC data from trapezius muscles were through a shoulder shrug against resistance. Subjects then performed FLS tasks while EMG data was being collected from the eight muscle groups. Three repetitions of each task were performed on each surgical platform. %MVC The primary outcome variable in this study was the %MVC, calculated in the standard manner for a study of this kind [18], as defined in the formula below: %MVC ¼
iEMG 100 %; MVC
where %MVC is the percentage of maximal voluntary contraction; iEMG is the rectified, processed, and integrated sEMG data for a particular muscle group during a task repetition; and MVC is the voltage generated by that muscle group during a maximal contraction. The %MVC value represents that percentage of maximal muscle effort
123
Surg Endosc
that is generated by task performance. We performed all analyses of raw sEMG data using the MATLABÒ numerical computing environment (MathWorks, IncorporatedÒ; Natick, MA).
significantly elevated during IS compared to both PT and PC (p = 0.0208, p = 0.0269, respectively). No other significant differences are noted. When comparing the FLS tasks to one another on the robotic platform, no significant difference in %MVC is seen in any muscle group.
Data analysis After performing each FLS task three times on a platform, a mean %MVC value was computed for each muscle group of the subject during a given task. Mean %MVC data was calculated for the full group. Mean %MVC values generated by laparoscopic and robotic task performance of each FLS task were compared using two-sided paired t tests. Data obtained from an individual subject on the laparoscopic platform was paired to data from the same subject on the robotic platform. A p value of\0.05 was considered the threshold of statistical significance. To compare FLS tasks to one another, we used ANOVA to perform a comparison of mean %MVC generated by the three FLS tasks in each muscle group. This analysis was performed separately on data derived from each surgical platform. An F statistic corresponding to a probability \0.05 was used as the threshold of statistical significance. Any muscle groups where a significant difference were further analyzed with pairwise comparisons of mean %MVC of each of the three FLS tasks to the other two tasks using two-sided paired t tests. A p value of\0.05 was considered the threshold of statistical significance.
Results Statistically significant differences in muscle activation between the laparoscopic and robotic platforms were noted for at least one muscle group during each FLS task (Fig. 1). Significantly increased right trapezius activation occurred during the robotic compared to the laparoscopic PT task (1.6 %MVC laparoscopic, 3.5 %MVC robotic, p = 0.0400). Significantly increased right trapezius activation occurred during the robotic compared to the laparoscopic PC task (1.3 %MVC laparoscopic, 3.6 %MVC robotic, p = 0.0018). Significantly increased right bicep muscle activation (2.7 %MVC laparoscopic, 1.3 %MVC robotic, p = 0.0190) and right deltoid muscle activation (2.4 %MVC laparoscopic, 1.0 %MVC robotic, p = 0.0190) occurred during the laparoscopic compared to the robotic IS task. When comparing the FLS tasks to one another on the laparoscopic platform (Fig. 2), a significant difference in mean muscle activation is seen in the right trapezius muscle group when comparing the three tasks (PT: 1.6 %MVC, PC: 1.3 %MVC, IS: 3.7 % MVC, F stat. 4.171, Sig. 0.036). Pairwise comparisons revealed that %MVC was
123
Discussion In this study, we describe the use of FLS tasks to study the comparative ergonomics of the laparoscopic and robotic surgical platforms. In our pilot sample with subjects representing varying levels of surgical training and experience, we have shown that the FLS PT, PC, and IS tasks can identify statistically significant differences in muscle activation during laparoscopic and robotic task performance. As expected, more significant differences were seen with the IS task, the most challenging FLS task performed in this study. In addition, all statistically significant differences were seen in muscle groups of the right upper extremity, the side of upper extremity dominance for all of the participating subjects. This may be due to greater exertion during task performance. Our data suggest that laparoscopic task performance may lead to increased activation of the right bicep and deltoid muscles, while robotic task performance may lead to increased right trapezius muscle activation in right-hand dominant individuals. Further study with a larger study population will be required to confirm these findings. The data show that when it comes to robotic task performance, we did not detect any ergonomic difference between PT, PC, and IS tasks. However, significant differences are demonstrated in FLS task performance on the laparoscopic platform. These findings suggest that ergonomic differences may exist between the FLS tasks, and inform future studies using this experimental model. Where differences were detected, the more complex IS task was associated with higher levels of muscle activation than simpler PT and PC tasks, suggesting that more difficult tasks may be associated with higher levels of ergonomic strain. Larger studies are needed to quantify the extent of the interaction between task difficulty and ergonomic strain. In addition, these findings suggest that the robotic platform may play some role in ‘‘equalizing’’ the ergonomic profile of simpler and more challenging FLS tasks. In summary, we have described the use of FLS tasks as an experimental model for studying comparative ergonomics of the laparoscopic and robotic surgical platforms. Further studies using this model will elaborate and expand upon the ergonomic differences identified in this study. As a pilot study, the small sample size limits the generalizability of our ergonomic findings to the general population of surgeons, and limits any subgroup analyses we could
Surg Endosc Fig. 1 Muscle activation during FLS task performance on laparoscopic and robotic platforms. *p \ 0.05
123
Surg Endosc Fig. 2 Comparative ergonomics of FLS tasks. PT FLS peg transfer, PC FLS pattern cutting, IS FLS intracorporeal suturing. *F stat. 4.171, Sig. 0.036
perform. We intend to use this model to study the effects, if any, that age, gender, hand-dominance, and surgical experience may have on the comparative ergonomic stress of the laparoscopic and robotic surgical platforms. In addition, while a body of literature does exist correlating FLS performance and intra-operative performance [21], no such data exist for the use of FLS tasks to evaluate surgical ergonomics. Future studies must elucidate the relationship between intra-operative and FLS ergonomic profiles. Finally, the technical limitation of an eight-channel-wired EMG setup limited the scope of our data collection to four muscle groups bilaterally. Future study will be required to expand on these findings to include muscles of the low back, forearm, hand, and lower extremity. Ergonomic differences between FLS tasks seen in this study support the use of multiple tasks in future ergonomic studies. Aside from being capable of identifying ergonomic differences, FLS tasks are well known to the surgical community, as being reproducible, low cost, and amenable performance by individuals of various levels of surgical experience. Our findings confirm our hypothesis that significant differences in muscle activation can be identified using these tasks and further lend support to the use of FLS tasks as an appropriate experimental model for the study of surgical ergonomics.
Conclusions FLS tasks are validated, readily available instruments that are feasible for use in demonstrating ergonomic differences
123
between surgical platforms. In this study, we used FLS tasks to compare mean muscle activation of four muscle groups during laparoscopic and robotic task performance. FLS tasks can serve as the basis for larger studies to further describe ergonomic differences between laparoscopic and robotic surgery. Acknowledgments The authors thank Gyusung Lee, PhD of the Department of Surgery at Johns Hopkins University (Baltimore, MD) for his valuable advice. This study was supported by a research grant from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES), and also by a research grant from Intuitive Surgical, Inc. (Sunnyvale, CA). Disclosures Dr. Zihni has received research grant funding for unrelated studies from the National Institutes of Health. Dr. Cavallo has received research grant funding for unrelated studies from the National Institutes of Health, the Society of American Gastrointestinal and Endoscopic Surgeons (SAGES), and the American Hernia Society in collaboration with DavolÒ Incorporated; and has served as a one-time consultant for Guidepoint GlobalÒ Incorporated. Dr. Cho has received research grant funding from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES) and Intuitive, Surgical Inc. (Sunnyvale, CA). Dr. Awad has received research grant funding from the Society of Gastrointestinal and Endoscopic Surgeons (SAGES) and Intuitive, Surgical Inc. (Sunnyvale, CA). Mr. Ohu and Ms. Ousley have no conflicts of interest or financial ties to disclose.
References 1. Bhogal RH, Athwal R, Durkin D, Deakin M, Cheruvu CN (2008) Comparison between open and laparoscopic repair of perforated peptic ulcer disease. World J Surg 32:2371–2374 2. Wilson CH, Sanni A, Rix DA, Soomro NA (2011) Laparoscopic versus open nephrectomy for live kidney donors. Cochrane Database Syst Rev. doi:10.1002/14651858.CD006124
Surg Endosc 3. Li MZ, Lian L, Xiao LB, Wu WH, He YL, Song XM (2012) Laparoscopic versus open adhesiolysis in patients with adhesive small bowel obstruction: a systematic review and meta-analysis. Am J Surg 204:779–786 4. Sari V, Nieboer TE, Vierhout ME, Stegeman DF, Kluivers KB (2010) The operation room as a hostile environment for surgeons: physical complaints during and after laparoscopy. Minim Invasive Ther Allied Technol 19:105–109 5. Park A, Lee G, Seagull FJ, Meenaghan N, Dexter D (2010) Patients benefit while surgeons suffer: an impending epidemic. J Am Coll Surg 210:306–313 6. Berguer R, Smith WD, Chung YH (2001) Performing laparoscopic surgery is significantly more stressful for the surgeon than open surgery. Surg Endosc 15:1204–1207 7. Berguer R, Chen J, Smith WD (2003) A comparison of the physical effort required for laparoscopic and open surgical techniques. Arch Surg 138:967–970 8. Lee G, Lee T, Dexter D, Godinez C, Meenaghan N, Catania R, Park A (2009) Ergonomic risk associated with assisting in minimally invasive surgery. Surg Endosc 23:182–188 9. Berguer R (1998) Surgical technology and the ergonomics of laparoscopic instruments. Surg Endosc 12:458–462 10. O’Sullivan OE, O’Reilly BA (2012) Robot-assisted surgery: impact on gynaecological and pelvic floor reconstructive surgery. Int Urogynecol J 23:1163–1173 11. Kumar P, Kommu SS, Challacombe BJ, Dasgup-Ta P (2010) Laparoendoscopic single-site surgery (LESS) prostatectomy– robotic and conventional approach. Minerva Urol Nefrol 62:425–430 12. Lunca S, Bouras G, Stanescu AC (2005) Gastrointestinal robotassisted surgery. A current perspective. Rom J Gastroenterol 14:385–391 13. Xia T, Baird C, Jallo G, Hayes K, Nakajima N, Hata N, Kazanzides P (2008) An integrated system for planning, navigation and robotic assistance for skull base surgery. Int J Med Robot 4:321–330 14. Frick AC, Falcone T (2009) Robotics in gynecologic surgery. Minerva Ginecol 61:187–199 15. Wright AS, Gould JC, Melvin WS (2004) Computer-assisted robotic antireflux surgery. Minerva Gastroenterol Dietol 50:253–260
16. Anton D, Gerr F, Meyers A, Cook TM, Rosecrance JC, Reynolds J (2007) Effect of aviation snip design and task height on upper extremity muscular activity and wrist posture. J Occup Environ Hyg 4:99–113 17. Jones T, Kumar S (2008) Comparison of ergonomic risk assessment output in a repetitive sawmill occupation: trim-saw operator. Work 31:367–376 18. Lee G, Lee T, Dexter D, Klein R, Park A (2007) Methodological infrastructure in surgical ergonomics: a review of tasks, models, and measurement systems. Surg Innov 14:153–167 19. Lofland KR, Mumby PB, Cassisi JE, Palumbo NL, Camic PM (1995) Assessment of lumbar EMG during static and dynamic activity in pain-free normals: implications for muscle scanning protocols. Biofeedback Self Regul 20:3–18 20. Edelman DA, Mattos MA, Bouwman DL (2012) Value of fundamentals of laparoscopic surgery training in a fourth-year medical school advanced surgical skills elective. J Surg Res 177:207–210 21. Antosh DD, Auguste T, George EA, Sokol AI, Gutman RE, Iglesia CB, Desale SY, Park AJ (2013) Blinded assessment of operative performance after fundamentals of laparoscopic surgery in gynecology training. J Minim Invasive Gynecol 20:353–359 22. Sweet RM, Beach R, Sainfort F, Gupta P, Reihsen T, Poniatowski LH, McDougall EM (2011) Introduction and validation of the American Urological Association Basic Laparoscopic Urologic Surgery skills curriculum. J Endourol 26:190–196 23. Berguer R, Smith W (2006) An ergonomic comparison of robotic and laparoscopic technique: the influence of surgeon experience and task complexity. J Surg Res 134:87–92 24. Lee GI, Lee MR, Clanton T, Sutton E, Park AE, Marohn MR (2013) Comparative assessment of physical and cognitive ergonomics associated with robotic and traditional laparoscopic surgeries. Surg Endosc 28:456–465 25. Vassiliou MC, Dunkin BJ, Marks JM, Fried GM (2010) FLS and FES: comprehensive models of training and assessment. Surg Clin N Am 90:535–558
123
