Wearable computing devices

Section Editor: Bennie G.P. Lindeque, MD Emerging Technology in Surgical Education: Combining Real-Time Augmented Reality and Wearable Computing Devices Brent A. Ponce, MD; Mariano E. Menendez, MD; Lasun O. Oladeji, MS; Charles T. Fryberger, BS; Phani K. Dantuluri, MD Abstract: The authors describe the first surgical case adopting the combination of real-time augmented reality and wearable computing devices such as Google Glass (Google Inc, Mountain View, California). A 66-year-old man presented to their institution for a total shoulder replacement after 5 years of progressive right shoulder pain and decreased range of motion. Throughout the surgical procedure, Google Glass was integrated with the Virtual Interactive Presence and Augmented Reality system (University of Alabama at Birmingham, Birmingham, Alabama), enabling the local surgeon to interact with the remote surgeon within the local surgical field. Surgery was well tolerated by the patient and early surgical results were encouraging, with an improvement of shoulder pain and greater range of motion. The combination of realtime augmented reality and wearable computing devices such as Google Glass holds much promise in the field of surgery. [Orthopedics. 2014; 37(11):751-757.] Surgery is a highly methodological field constantly in The authors are from the Department of Orthopaedics (BAP, MEM, LOO, CTF), University of Alabama at Birmingham, Birmingham, Alabama; and the Department of Orthopaedics, Emory University (PKD), Atlanta, Georgia. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Brent A. Ponce, MD, Department of Orthopaedics, University of Alabama at Birmingham, Orthopaedic Specialities Bldg, 1313 13th St S, Birmingham, AL 35294-5327 (bponce@ uabmc.edu). Received: December 4, 2013; Accepted: February 20, 2014; Posted: November 6, 2014. doi: 10.3928/01477447-20141023-05 need of technological advancements aimed at improving patient outcomes while facilitating cost-effective treatment strategies, knowledge transfer, and skill acquisition. 1-4 For a technology to have application to surgery, it must offer utility in a portable, fiscally responsible package. Wearable computing devices such as Google Glass (GG) (Google Inc, Mountain View, California) have recently aroused the interest of the medical community. In contrast to traditional videoconferencing platforms, GG is a device with an optical headmounted display that possesses the ability to capture and display audio and video images in real time while interacting with the surrounding environment. Flexible mobile platforms such as GG could hold considerable potential in furthering the development of telemedicine (ie, the remote diagnosis and treatment of patients by means of telecommunications technology) as a tool to spread time-sensitive medical expertise to areas that are physically difficult to reach. 5-7 Google Glass has been tested in several academic medical centers worldwide to stream live point-of-view footage from surgeries to the medical community. 8-11 Early adopters have praised the device s portability and ease of use; however, real-time broadcasts of operative cases using traditional videoconferencing platforms over the Internet have been reported since the late 1990s. 12-14 Currently, no peer-reviewed reports have described limitations or potential concerns with adoption of this tool by the surgical community. Of the more than 16,000 citations for telemedicine on PubMed (Medline), fewer than 250 pertain to surgery, suggesting that the rapid growth in telehealth has largely not affected the realm of surgery. Augmented reality is a separate emerging technology that also has a promising future in medicine and especially in surgery. 15-17 Whereas NOVEMBER 2014 Volume 37 Number 11 751

A Figure 2: Preoperative shoulder anteroposterior radiograph (A) and coronal T2-weighted magnetic resonance image (B). Postoperative anteroposterior radiograph (C). B Figure 1: Composite surgical field seen by student surgeon and teacher surgeon, using the Virtual Interactive Presence and Augmented Reality system (University of Alabama at Birmingham, Birmingham, Alabama). virtual reality replaces the real world with a simulated one, augmented reality can be defined as enhancing an individual s visual experience with the real world through the integration of digital visual elements. The Virtual Interactive Presence and Augmented Reality (VIPAAR) system, an augmented reality platform conceptualized and developed at the University of Alabama at Birmingham, has effectively demonstrated the practicality and potential usefulness of virtual interactive guidance in the fields of neurosurgery, otolaryngology, and orthopedics. 7,18,19 The core concept of the VIPAAR system is virtual interactive presence (VIP); VIP enables an expert, or a helper, to view a remote task (surgical) field and insert his or her hands or instruments virtually into the remote field for real-time guidance, training, and assistance as needed. In essence, VIP merges 2 realities into a single shared task field, enabling participants to interact as if they were physically together (Figure 1). 7 This technology has been validated as effective for guidance and training using surgical visualization systems such as microscopes, endoscopes, and mounted high-definition cameras that capture the surgical field. 7,18,19 Although evaluation of GG suggests it has a valuable role in live point-of-view video recording, the application of GG as a mobile, augmented reality interface remains untested in a surgical setting. 8-11 In this report, the authors describe the first surgical procedure combining the VIPAAR system and GG, which was performed on September 12, 2013, in Birmingham, Alabama. The integration of augmented reality platforms and applications with wearable devices such as GG opens all of surgery to the possibility of expert remote assistance, ultimately aiding in the development of surgical C telementoring. The purpose of this study was to analyze the feasibility of augmented reality technology with a mobile videoconferencing platform in a surgical setting. The authors hypothesized that this pairing would result in a robust construct providing a portable mechanism for the implementation of VIP. The primary questions and challenges addressed in this article are related to the applicability and limitations of GG in the surgical environment, including its ability to host effective virtual interactive systems (eg, VIPAAR) for surgical assistance or education, ethical and confidentiality implications, and its role in the development of surgical telementoring. Methods Case Description A 66-year-old man presented to the authors institution with 5 years of progressive right shoulder pain and decreased range of motion. Physical examination and radiographs were consistent with advanced osteoarthritis with an intact rotator cuff and adequate glenoid bone stock (Figures 2A-B). Secondary to persistent pain despite nonoperative treatment with nonsteroidal anti-inflammatory drugs and activity modification, the patient elected to undergo a total shoulder replacement. His preoperative American Shoulder and Elbow Surgeons (ASES) score was 40, and his preoperative Disabilities of the Arm, Shoulder and Hand (DASH) score was 53.5. The patient was aware of the intended study and provided signed consent to allow broadcasting and transmission of data through GG to a collaborating institution. The patient also consented to the details of the case being published. VIPAAR: Virtual Interactive Presence The VIPAAR system is software based and implements VIP by merging, in real 752 ORTHOPEDICS Healio.com/Orthopedics

time, 2 video streams that capture separate and remote fields into a common task field, thus enabling real-time interaction between participants in that common task field (Figure 1). That is, participants can see each other s actions in the common task field, as rendered by the VIPAAR system, as if they were physically present within the task field. 7 In this case, the common task field was the surgery being performed in Birmingham. The system was used to merge a remote surgeon s hands (a surgeon at Saint Joseph s Hospital, Atlanta, Georgia) into the common surgical field (in Birmingham) using GG. Logistical Set-up Two experienced, fellowship-trained orthopedic surgeons (B.A.P., P.K.D.) participated in this case combining the use of GG and augmented reality. The officiating surgeon performing the surgery (Surgeon A: B.A.P.) was located in an operating room at the University of Alabama at Birmingham Highlands Hospital, Birmingham, Alabama, while the second surgeon (Surgeon B: P.K.D.) was remotely located in a conference room at Resurgens Orthopaedics, Emory Saint Joseph s Hospital, Atlanta, Georgia. A VIP station with an Internet protocolbased connection was positioned in Atlanta. Surgeon A in Birmingham wore GG during the entire case, which enabled him to both interact with and stream live video to Surgeon B in Atlanta. The VIP station positioned in Atlanta received a Figure 3: Schematic diagram of signal transmission. The local surgeon and local elements are physically present in the field of interest. The remote surgeon is not physically present in the field of interest. Each participant views a common field of interest, composed of differing combinations of local and remote elements or participants. streamed video input from the GG camera, thus allowing Surgeon B to virtually reach into the surgical field in real time and remotely assist Surgeon A from a different geographic location. Thus, the attending surgeon (Surgeon A) performing the total shoulder arthroplasty in Birmingham was able to see a hybrid image combining the image of the surgical field with the image of his colleague s hands or tools through the GG head-mounted display. This set-up is shown in Figure 3. The attending surgeon in Birmingham had 3 additional pieces of equipment beyond the arthroplasty suits used in joint replacement surgery. The first piece was GG, which was connected to an extended battery located in the surgeon s back scrub pocket. The second was a headset for audio that was connected to a cell phone placed in the surgeon s front scrub pocket; the audio headset allowed the surgeon to hear the remote surgeon, and the microphone in the cell phone allowed the remote surgeon to hear the operating surgeon through a Skype (Microsoft, Redmond, Washington) conference call. The third was the microphone of the television station recording the broadcast, which was attached to the lapel of the scrub shirt and connected to a transmitter on the surgeon s waist. The surgeon was assisted by a resident and a nurse first assistant in addition to the scrub technician and other operating room personnel, including the circulating nurse and the anesthesiologist. Results Surgical Outcomes The patient tolerated the surgery well and was discharged from the hospital the next day. Early surgical results were encouraging, with an improvement of shoulder pain and greater range of motion. In this case, the operative time was approximately 45 minutes longer than usual for this procedure when performed by Surgeon A. A postoperative radiograph demonstrated appropriate alignment with no evidence of failure (Figure 2C). At 1 year postoperatively, the patient continues to express satisfaction with the operation. His 1-year postoperative ASES score was 100 and his DASH score was.8. Technology and Policy Challenges Encountered Before Surgery Prior to broadcasting the live surgery, GG and its hosting of the VIPAAR system was tested. Two key informa- NOVEMBER 2014 Volume 37 Number 11 753

Figure 4: Divergent field of views (Google Glass [Google Inc, Mountain View, California] and surgeon). tion technology and policy concerns required solutions. Secure Network Access. Google Glass does not allow for entry of user name and password for network authentication. Because hospital network security mandates the use of such authentication, for this pilot, the University of Alabama at Birmingham enabled explicit access for GG. Health Insurance Portability and Accountability Act (HIPAA) and Confidentiality. Because GG requires that users communicate through a Google Hangout video session, which is not HIPAA compliant, provisions were made to protect patient privacy and confidentiality. These included patient consent for use of GG and VIPAAR, as well as assurance that no identifiable HIPAA information would be transmitted during the session. Overall Performance of GG During the Surgical Trial The GG form factor was convenient and relatively unobtrusive for Surgeon A. In general, the form factor was more convenient and less obtrusive than a camera mounted in the operating room for the purpose of capturing the surgical field. Limitations Associated With the Use of GG Recognizing that GG is a first-generation prototype, this singular experience enabled identification of several issues important to the eventual commonplace use of GG in the surgical environment. GG Battery Life. During the surgery, GG continually sent and received real-time video, which required significant encoding/decoding and processing. The battery life was limited. To remain on beyond 20 to 30 minutes, GG had to be connected to a power source. Audio. The audio was adequate only for the remote participant (consulting Surgeon B). That is, the receiving station in Atlanta was able to hear the operating surgeon (Surgeon A) at the University of Alabama at Birmingham, but the operating surgeon was unable to hear what was spoken by the consulting remote surgeon. This could be related to operating room noise, the battery pack used to power the head fan employed by the surgeon during arthroplasty procedures, or the surgeon wearing GG not being the one who was custom-fitted for the device by Google. For this particular case, Skype teleconferencing software coupled with a cell phone in the front scrub pocket and a headset worn by the surgeon allowed for adequate audio for communication. Image Quality. The screen resolution of the GG display is 640 360 pixels. The remote surgeon (Surgeon B) felt that the image transmitted by GG, although not high-definition due to GG s limited processing power, allowed him to effectively provide real-time guidance. The image viewed by Surgeon A through GG was of lower resolution and posed some problems with fine details of the surgical field. Additionally, Surgeon A, who wears glasses, had to wear contacts to clearly view the GG display. Line of Sight. The surgical field is generally viewed by directing gaze downward, not tilting the head, which yields a view different from that captured by the GG camera. Thus, the remote surgeon did not always see exactly what the local surgeon s eyes were fixed on. The local surgeon had to position his head excessively downward to align the GG camera (ie, GG field of view) with the surgical field of interest (ie, surgeon s field of view) (Figure 4). In addition, looking up to see the heads-up display (and hence the interaction with Surgeon B) was at times unnatural. The local surgeon had to divert his gaze away from the surgical field to the heads-up display to see the interaction with the remote surgeon; this would also be the case regardless of whether the screen held interactive or static information (eg, radiographs, magnetic resonance images, vital signs) (Figure 4). Although Surgeon A s contacts were helpful, allowing him to view the GG heads-up display and interact with Surgeon B, the image quality for the GG transmission to the remote surgeon was better when GG was closer to the surgical field than what was generally comfortable for Surgeon A s contact-corrected focal length. Both of these issues made the transmitting and receiving of information challenging. Network Delay. There was a noticeable delay between the audio and video. The audio, which was provided by a teleconference call, was ahead of the video because the surgical image was sent back to Mountain View, California (Google Hangout), and sent 754 ORTHOPEDICS Healio.com/Orthopedics

back to Birmingham and Atlanta. Hence, when Surgeon B wanted to identify something in the surgical field, Surgeon A had to temporarily stop operating, look up to the heads-up display, and wait for the video to catch up with what was being spoken. Overall Performance of GG Combined With VIPAAR Google Glass supported integration with the VIPAAR system, enabling the local surgeon to interact with the remote surgeon within the local surgical field (Figure 5). Surgeon A reported that he was able to successfully view Surgeon B s presence for the duration of the case. Surgeon B reported that the experience of inserting his hands into the simulated surgical field felt natural, allowing more precise instruction than through verbal interaction. Figure 5: Remote surgeon at the Virtual Interactive Presence and Augmented Reality (University of Alabama at Birmingham, Birmingham, Alabama) station inserting his hand, in real time, into the surgical field in Birmingham, Alabama. Discussion In a financially austere health care marketplace, emerging technology is a key factor in constraining costs while improving efficiency and the quality of care. 20-22 However, for new technology to be adopted, health care providers and educators need to actively justify the cost of such technology and demonstrate measurable improvements to patient health care and medical education as a result. The combination of real-time augmented reality and wearable computing devices such as GG represents a novel breakthrough technology in the field of surgery, poised to irreversibly change health care and medical education. Nonetheless, the authors feel the need to highlight several aspects of GG s functionality as it is used to host interactive augmented reality applications in the future. Although this may temper current enthusiasm regarding GG, a realistic understanding of the areas where improvements can unlock the potential value of this technology should be valuable to both technology developers and health care providers. Surgery requires a high degree of technical skill acquired through an apprenticeship model of stepwise involvement in the operating room that has remained largely unchanged for generations. 23 Given the accelerating complexity within the surgical field, coupled with fewer opportunities for residents to perform surgery, emphasis is currently shifting toward skill acquisition outside the operating room. 23-25 This study demonstrated the application of a GG plus VIP construct between a local and a remote surgeon. For this operation, Surgeon A and Surgeon B were both fellowshiptrained shoulder specialists; however, there is a paradigm for employing this construct with a resident and an attending physician. 18 A recent study by Mattar et al 25 revealed deficits in operative skills and autonomy among general surgery graduate trainees entering accredited surgical subspecialty fellowships in the United States. In the realm of orthopedic surgery, research conducted by Karam et al 26 identified the importance of surgical skills laboratories and simulation technology as a required component of orthopedic residency training; however, only half of residency programs in the United States have a skills laboratory and program. 26 The recent implementation of virtual reality simulation training has been successful in shortening the learning curve of surgical trainees by allowing them to achieve technical skill milestones more rapidly, with the additional benefit of not compromising patient care or extending the length of operations. 27-29 Despite encouraging results, virtual reality simulators are imperfect models of the human body. Their interfaces, although sophisticated, do not allow trainees to view, feel, and manipulate the simulators the way they would a native environment. 30 The use of wearable, lightweight computing devices (eg, GG), with augmented reality technologies (eg, VIPAAR), may aid in propelling the further development of surgical telementoring by facilitating the transfer of complex skills from simulated environments to the operating room. In the real-time augmented reality environment generated by VIP, 2 physical realities are merged to provide a shared first-person environment for learning; hence, a remote surgeon can see what the operating surgeon sees and virtually identify relevant anatomy or help guide the surgical technique. 7 The promising technology combination described here has the potential to bridge the gap between simulated environments and real surgical environments, provided its cost-effectiveness is demonstrated and several technical and ethical concerns outlined below are appropriately addressed. The beta version of GG, with its built-in computer and connectivity, is an effective form factor for transmitting NOVEMBER 2014 Volume 37 Number 11 755

images of what the user sees and easily seeing text and images through the heads-up display. There have been favorable reports of surgeons using GG during surgery; however, these reports demonstrated using GG to capture and record surgery or to inject text, numeric, and image data into the display for viewing as needed. 8-11 There have also been reports 31 of using GG for asynchronous consultation with remote experts who view the surgical field. Although there may be value in these implementations, no report has described using GG to host real-time interaction for assistance or guidance within the surgical field as captured by the glasses. The authors have described a novel use of GG to host an interactive augmented reality application for surgical guidance. Their experience with GG to host such real-time interaction has allowed them to identify key issues that should be addressed for the most effective use in a surgical setting. Given its enormous potential value for surgical training and assistance, the authors hope that GG technology will evolve to longer battery life, increased processor power providing higher-definition video image quality, an operating room-optimized matching of surgeon and camera view lines, and improved sound quality. Another improvement would be a binocular heads-up display, instead of the current monocular display. Virtual interactive presence is a relatively new technology that has been implemented in surgery on a limited basis. Early implementations of this technology used existing visualization systems such as endoscopes, operating microscopes, and operating room cameras. 7,18,19 Integration with endoscopy fit in well with existing workflow, since the surgeon operates in the same field within which the remote surgeon s hands are merged. That is, the remote surgeon s hands are seen on the arthroscopy tower monitor, allowing the operating surgeon to view the surgical field as normal while additionally seeing the remote surgeon s hands point to anatomy in real time. Integration with microscopes and other visualization solutions (mounted cameras) required the surgeon to look at a separate monitor to see the merged image. Although useful, this was not the same as seeing the remote surgeon s hands superimposed over the actual surgical field as the operating surgeon worked. Early VIPAAR systems required a cart in the operating room; recent mobile devicebased solutions have reduced the need for an in-room presence, freeing operating room space. Currently, VIP is an audio-visual interactive solution, without tactile feedback. As the use of augmented reality software in surgical education grows, the addition of tactile feedback should enhance the learning and teaching experience. Several shortcomings of this study should be kept in mind, the most significant being that this was a single surgeon s experience involving a single surgical case. In addition, the authors did not seek to quantify benefits or estimate costs related to the adoption of this technological construct. Another limiting factor was that 2 experts in the field of shoulder surgery were involved in this study; therefore, knowledge transfer and skill acquisition were limited. Mainly owing to patient safety concerns and to minimize potential unexpected complications arising from the piloting of this technology combination, the authors did not feel comfortable having a resident perform the surgery while being guided by the remote consulting surgeon. Further research employing the aforementioned study design is warranted. As surgeons increase their use of GG and related technologies, political, regulatory, and financial concerns will need to be addressed at a broad level. A few of these include medicolegal implications for the remote surgeon if untoward events occur, reimbursement for the assistance provided by the consulting surgeon, HIPAA and hospital network security concerns, informed patient consent, and financial support required for such emerging technologies. Conclusion This project demonstrated that GG can be mounted and worn in the operating room and that the system can host facilitative technology applications such as VIPAAR. However, its use as a real-time surgically optimized augmented reality interface is not yet practical. Improvements to GG such as longer battery life, increased processor power providing higher-definition video image quality, an operating roomoptimized matching of surgeon and camera view lines, and better sound quality will enhance its performance in the operating room. Improvements in GG and communications infrastructure will make the integration of head-mounted, line-of-sight systems with real-time mentoring technology increasingly valuable for surgical interaction and mentoring. References 1. Gawande A. Two hundred years of surgery. N Engl J Med. 2012; 366(18):1716-1723. 2. Cosman PH, Shearer CJ, Hugh TJ, Biankin AV, Merrett ND. A novel approach to high definition, high-contrast video capture in abdominal surgery. Ann Surg. 2007; 245(4):533-535. 3. Maeso S, Reza M, Mayol JA, et al. Efficacy of the Da Vinci surgical system in abdominal surgery compared with that of laparoscopy: a systematic review and meta-analysis. Ann Surg. 2010; 252(2):254-262. 4. Nguyen NT, Hinojosa MW, Finley D, Stevens M, Paya M. Application of robotics in general surgery: initial experience. Am Surg. 2004; 70(10):914-917. 5. Joseph B, Hadeed G, Sadoun M, Rhee PM, Weinstein RS. Video consultation for trauma and emergency surgical patients. Crit Care Nurs Q. 2012; 35(4):341-345. 6. Lewis ER, Thomas CA, Wilson ML, Mbarika VW. Telemedicine in acute-phase injury management: a review of practice and advancements. Telemed J E Health. 2012; 18(6):434-445. 7. Shenai MB, Dillavou M, Shum C, et al. Virtual interactive presence and augmented reality 756 ORTHOPEDICS Healio.com/Orthopedics

(VIPAR) for remote surgical assistance. Neurosurgery. 2011; 68(1 suppl):200-207. 8. Chang J. Google Glass assists surgeons and medical students at Ohio State University. http:// abcnews.go.com/technology/ google-glass-assists-surgeonsmedical-students-ohio-state/ story?id=20109218. Accessed September 17, 2013. 9. Hay T. Google Glass could become a fixture in the operating room. http://blogs.wsj.com/ venturecapital/2013/08/12/ google-glass-could-becomea-fixture-in-the-operatingroom/?mod=wsj_streaming_latest-headlines. Accessed September 17, 2013. 10. Ekatha JA. In a first, Chennai doctor uses Google Glass to air operation live. http://articles.timesofindia.indiatimes. com/2013-09-18/gadgetsspecial/42181937_1_googleglass-gadget-operaion-theatre. Accessed September 18, 2013. 11. De Benito E. El quirofano global, de la mano de Google Glass. http://www.sociedad.elpais. com. Accessed September 17, 2013. 12. Broderick TJ, Harnett BM, Doarn CR, Rodas EB, Merrell RC. Real-time Internet connections: implications for surgical decision making in laparoscopy. Ann Surg. 2001; 234(2):165-171. 13. Gandsas A, Altrudi R, Pleatman M, Silva Y. Live interactive broadcast of laparoscopic surgery via the Internet. Surg Endosc. 1998; 12(3):252-255. 14. Rafiq A, Moore JA, Zhao X, Doarn CR, Merrell RC. Digital video capture and synchronous consultation in open surgery. Ann Surg. 2004; 239(4):567-573. 15. Abe Y, Sato S, Kato K, et al. A novel 3D guidance system using augmented reality for percutaneous vertebroplasty. J Neurosurg Spine. 2013; 19(4):492-501. 16. Marzano E, Piardi T, Soler L, et al. Augmented realityguided artery-first pancreaticoduodenectomy. J Gastrointest Surg. 2013; 17(11):1980-1983. 17. Mitha AP, Almekhlafi MA, Janjua MJ, Albuquerque FC, McDougall CG. Simulation and augmented reality in endovascular neurosurgery: lessons from aviation. Neurosurgery. 2013; (72 suppl 1):107-114. 18. Ponce BA, Jennings JK, Sheppard ED, et al. Telementoring: augmented reality in orthopaedic education. Paper presented at: American Academy of Orthopaedic Surgeons; March 19-23, 2013; Chicago, IL. 19. Phillips JD, Withrow K. Virtual interactive presence: an operative feasibility study. Paper presented at: American Academy of Otolaryngology Head and Neck Surgery Annual Meeting; September 9-12, 2013; Washington, DC. 20. Chapman WC. No silver bullet in liver transection: what has 35 years of new technology added to liver surgery? Ann Surg. 2009; 250(2):204-205. 21. Koopmann MC, Kudsk KA, Szotkowski MJ, Rees SM. A team-based protocol and electromagnetic technology eliminate feeding tube placement complications. Ann Surg. 2011; 253(2):287-302. 22. Kumar RK. Technology and healthcare costs. Ann Pediatr Cardiol. 2011; 4(1):84-86. 23. Hodgins JL, Veillette C. Arthroscopic proficiency: methods in evaluating competency. BMC Med Educ. 2013; 13:61. 24. Kassab E, Tun JK, Arora S, et al. Blowing up the barriers in surgical training: exploring and validating the concept of distributed simulation. Ann Surg. 2011; 254(6):1059-1065. 25. Mattar SG, Alseidi AA, Jones DB, et al. General surgery residency inadequately prepares trainees for fellowship: results of a survey of fellowship program directors. Ann Surg. 2013; 258(3):440-449. 26. Karam MD, Pedowitz RA, Natividad H, Murray J, Marsh JL. Current and future use of surgical skills training laboratories in orthopaedic resident education: a national survey. J Bone Joint Surg Am. 2013; 95(1):e4. 27. Aggarwal R, Ward J, Balasundaram I, Sains P, Athanasiou T, Darzi A. Proving the effectiveness of virtual reality simulation for training in laparoscopic surgery. Ann Surg. 2007; 246(5):771-779. 28. Grantcharov TP, Bardram L, Funch-Jensen P, Rosenberg J. Learning curves and impact of previous operative experience on performance on a virtual reality simulator to test laparoscopic surgical skills. Am J Surg. 2003; 185(2):146-149. 29. Henn RF III, Shah N, Warner JJ, Gomoll AH. Shoulder arthroscopy simulator training improves shoulder arthroscopy performance in a cadaveric model. Arthroscopy. 2013; 29(6):982-985. 30. Lange T, Indelicato DJ, Rosen JM. Virtual reality in surgical training. Surg Oncol Clin N Am. 2000; 9(1):61-79. 31. Armstrong DG, Rankin TM, Giovinco NA, Mills JL, Matsuoka Y. A heads-up display for diabetic limb salvage surgery: a view through the Google looking glass. J Diabetes Sci Technol. 2014; 8(5):951-956. NOVEMBER 2014 Volume 37 Number 11 757