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Effects of Preoperative Virtual Reality Magnetic Resonance Imaging on Preoperative Anxiety in Patients Undergoing Arthroscopic Knee Surgery: A Randomized Controlled Study
Original Article with Video Illustration
Effects of Preoperative Virtual Reality Magnetic Resonance Imaging on Preoperative Anxiety in Patients Undergoing Arthroscopic Knee Surgery: A Randomized Controlled Study Jae-Hyuk Yang, M.D., Ph.D., Jae Joon Ryu, M.D., Eunwoo Nam, Ph.D., Hee-Suk Lee, A.S., and Jin Kyu Lee, M.D., Ph.D.
Purpose: To assess the effect of a preoperative virtual reality (VR) experience of 3-dimensional (3D) reconstructed magnetic resonance images (MRIs) on anxiety reduction in patients undergoing arthroscopic knee surgery. Methods: Patients in the VR group watched a 3D model of their own MRI through a VR headset describing the anatomy of the knee as well as their own lesion of interest for an arthroscopic procedure. Patients in the non-VR (NR) group received standard preoperative information about their MRI. The primary outcome for analysis was the Amsterdam Preoperative Anxiety and Information Scale score to measure level of anxiety and the need for information in patients undergoing arthroscopic knee surgery. Secondary outcomes were rated with visual analog scale (VAS) scores measuring patient pain, preparedness, satisfaction, and stress. Results: Regarding the Amsterdam Preoperative Anxiety and Information Scale score, the sum S (surgery-related anxiety) and sum C (combined anxiety component) subscales showed significantly better outcomes in the VR group (median [interquartile range] for sum S ¼ 2.0 [2.0-4.0], median [quartile 1-quartile 3] sum C ¼ 4.0 [4.0-8.5]) than in the NR group (median [interquartile range] for sum S ¼ 4.9 [3.0-5.0], median [quartile 1-quartile 3] sum C ¼ 8.0 [5.3-9.8]) (P ¼ .014 and P ¼ .005, respectively). Regarding VAS scores, preoperative measures showed significantly better outcomes in satisfaction among VR group patients (95 [90.0-100.0]) in comparison to NR group patients (85 [70.0-96.0]) (P ¼ .010). For postoperative VAS measures, the VR group (satisfaction score ¼ 95 [90.0-100.0], stress score ¼ 15 [2.5-37.5]) showed significantly better outcomes in satisfaction and stress in comparison to the NR group (satisfaction score ¼ 85 [70.0-97.5], stress score ¼ 30 [30.050.0]). Conclusions: Application of preoperative VR experience of 3D reconstructed knee MRIs in patients undergoing arthroscopic knee surgery reduces anxiety around surgical encounters. The VR patient group was more satisfied overall and less stressed postoperatively. However, perioperative pain and preparedness were not affected by VR exposure. Level of Evidence: Level I, randomized controlled trial.
See commentary on page 2400
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urgery is a stressful event, and most patients admitted for surgery experience some degree of anxiety during the preoperative period.1,2 Preoperative anxiety may be influenced by multiple factors, including
patient age, sex, type of surgery, rapport with medical staff, previous experience or knowledge of surgical procedures, and personal characteristics and susceptibility to stressful situations.3,4 Most of the time, patients use
From the Department of Orthopaedic Surgery, Hanyang University Guri Hospital (J-H.Y.), Guri, Gyeonggi-do; Department of Orthopaedic Surgery, Hanyang University Hospital (J.J.R., J.K.L.), Seoul; Biostatistical Consulting and Research Laboratory, Hanyang University College of Medicine (E.N.), Seoul; and VRAD Inc., (H-S.L.), Seoul, Republic of Korea. The authors report the following potential conflicts of interest or sources of funding: The Ministry of SMEs and Startups provided funding for this research: C0515624. Full ICMJE author disclosure forms are available for this article online, as supplementary material. The trial was registered at ClinicalTrials.gov (a service of the U.S. National Institutes of Health), with a trial identification number of NCT03426163.
Received September 21, 2018; accepted February 17, 2019. Address correspondence to Jin Kyu Lee, M.D., Ph.D., Department of Orthopaedic Surgery, Hanyang University College of Medicine, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. E-mail: [email protected] Ó 2019 Published by Elsevier on behalf of the Arthroscopy Association of North America 0749-8063/181152/$36.00 https://doi.org/10.1016/j.arthro.2019.02.037
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Fig 1. Consolidated Standards of Reporting Trials (CONSORT) flowchart.
coping mechanisms to regulate their emotions,5 but when distressing psychological symptoms are unchecked, these symptoms may have a negative impact on treatment results and recovery after surgery.6 A lack of education and misinformation regarding indicated surgical procedures have been suggested as significant factors that influence perioperative anxiety and patient compliance with treatment.7-10 Providing visualized information before surgical procedures has proved to reduce anxiety in various surgeries.7,11-13 Magnetic resonance imaging (MRI) allows physicians to provide patients with pathology information by showing the MRIs before scheduling surgery.14 Very often, however, it is not easy for a patient to fully understand the process by seeing a single section of an MRI for a limited time.15 Two-dimensional (2D) images presented in slices (e.g., axial, sagittal, and coronal), which patients view on monitors, often limit patients from visualizing the proper orientation of the knee. In light of this, attempts have been made to reconstruct 3D knee images by volume-rendering techniques based on MRI. Mallikarjunaswamy et al.16 used a volumerendering technique to reconstruct a 3D knee model following the segmentation of menisci from knee MRIs. 3D MRI has been shown to be helpful in evaluation and diagnosis of pathology, as 3D imaging allows demonstration of fine anatomic detail and manipulation of the images by removal or transparency of unwanted overlying structures, thus emphasizing the area of interest.17 Virtual reality (VR) is a technology that may further
enhance patient understanding of 3D models by allowing both physicians and patients to “fly” inside an imaginary body to understand the anatomy and indicated surgical procedures.18 The purpose of this study was to assess the effect of preoperative VR experience of 3D reconstructed knee MRIs on anxiety reduction in patients undergoing arthroscopic knee surgery. We hypothesized that patients presented with a preoperative VR experience of 3D reconstructed knee MRIs would show reduced anxiety in comparison with knee arthroscopic surgery patients undergoing a standard preoperative process.
Methods The institutional review board of the hospital at Hanyang University approved this study, and all patients provided informed consent. The trial was registered at ClinicalTrials.gov (a service of the U.S. National Institutes of Health). Patients Between January and June 2018, 61 patients expected to undergo elective arthroscopic knee surgery under general anesthesia were assessed for eligibility for this prospective, randomized controlled trial. Exclusion criteria were poor MRIs taken at other hospitals, diagnostic arthroscopic procedures without evident findings on MRI, arthroscopic procedures on both knees, osteoarthritic change (Kellgren-Lawrence grade 3), a history of surgery on a corresponding knee, and refusal
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to join the study. A total of 48 patients were enrolled in the study (Fig 1). Arthroscopic procedures were categorized into 3 groups: (1) cruciate ligament reconstruction surgery, (2) meniscus surgery (repair or meniscectomy), and (3) cartilage surgery (simple debridement or microfracture). Interventions Patients were randomized into 2 groups using a computer-generated random sequence. Randomization occurred during the clinic visit after the patient had agreed to undergo arthroscopic surgery and had signed consent to join the study. Because of the nature of the study, both patients and physicians were aware of study group assignments. However, the single assessor (J.J.R.) collecting the outcome data was blinded to the study group assignments. Group VR consisted of 24 patients (24 knees) set to receive a preoperative VR experience, whereas group non-VR (NR) consisted of 24 patients (24 knees) who were to receive standard preoperative information. Patients in the VR group watched a 3D model of their own MRIs through a VR headset (Vive; HTC, New Taipei City, Taiwan) describing the anatomy of the knee as well as their own lesion of interest in need of arthroscopic procedure. Patients in the NR group received standard preoperative information about their MRIs through a picture-archiving and communications system (p-viewer v. 5.0.8.1; Infinite, Seoul, Korea). All patients were provided with pathology information by viewing the MRIs before scheduling surgery at the outpatient clinic, and MRIs through either a VR headset or a picture-archiving and communications system were shown again to patients 1 day (w12 hours) before surgery during the time of preoperative counseling after patients were admitted to the hospital. All images were described by a single surgeon (J.K.L.) who was to perform the arthroscopic procedure. Visualization Process A trained researcher with expertise in 3D modeling segmented the knee MRIs of patients under the supervision of surgeons. Digital Imaging and Communications in Medicine images that consisted of >100 sagittal slices were used as inputs. Section thickness and intersection gaps were 3 and 0.3 mm, respectively. Software 3D Slicer 4.6.2 (Brigham and Women’s Hospital and The Slicer Community, Boston, MA) was used for segmentation, focusing primarily on structures including cruciate ligaments, menisci, cartilage, and collateral ligaments.19 After segmentation in the 3D Slicer, the Digital Imaging and Communications in Medicine file images were converted to .rnnd files to obtain a 3D array of data. Subsequently, surface extraction rendering processes were performed to obtain mesh (surface) data in the .obj file format.20
Software including Autodesk 3ds Max (Autodesk, San Rafael, CA) and ZBrush (Pixologic, Los Angeles, CA) were used to apply final feedback and to change the surface data. Finally, a reconstructed 3D model was exported as an .fbx file, including a texture map. Unreal Engine 4 software (Epic Games, Potomac, MD) was used to render reconstructed 3D models with realistic textures in head-mounted displays on HTC Vive viewers. Hand motion controllers were assigned to the 3D pointer models to provide a real-time tracking system (Video 1, available at www.arthroscopyjournal.org). Outcome Variables The primary outcome for analysis was Amsterdam Preoperative Anxiety and Information Scale (APAIS) score to measure level of anxiety and the need for information in patients.21 Patient APAIS scores were obtained preoperatively on the day of the surgical procedure. The APAIS scale is a validated self-reported instrument to assess preoperative patient anxiety. The questionnaire consists of 2 scales, an anxiety-related scale and an information-need scale related to the situation of waiting for surgery. The instrument has 6 items rated by the patient on a 5-point Likert scale. The APAIS anxiety scale is the sum of items 1, 2, 4, and 5, with a score range from 4 (lowest) to 20 (highest), and the APAIS information-need scale is the sum of items 3 and 6, with a score range from 2 to 10. Four subscales consist of (1) anesthesia-related anxiety (sum A, range ¼ 2-10), (2) surgery-related anxiety (sum S, range ¼ 2-10), (3) an information-need component (sum I, range ¼ 2-10), and (4) a combined anxiety component (sum C, range ¼ 4-20). A score >11 on the APAIS anxiety scale (sum C) indicates that the patient is experiencing anxiety requiring further intervention. Patients with a score of 5 or higher for the APAIS information-need scale (sum I) require information about topics of concern. The higher the score, the greater the degree of anxiety or need for additional information on the part of patients. Secondary outcomes were visual analog scale (VAS) scores (with a range of 0 [worst] to 100 [best]) measuring patient pain, preparedness, satisfaction, and stress. VAS scores were obtained twice preoperatively on the day of surgery and on postoperative day 3. The postoperative survey was identical to the preoperative survey except omitting items regarding preparedness. Statistical Analysis Statistical analysis was done with SPSS version 18.0 for Windows (SPSS, Chicago, IL). Data for VR and NR groups were compared statistically using the Student t test, the c-squared test, the Fisher exact test, and the Wilcoxon rank-sum test as appropriate. A value of P < .05 was regarded as significant. Sample size calculation was conducted before recruiting the patients. Sample
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VIRTUAL REALITY OF RECONSTRUCTED MRI Table 1. Patient Characteristics and Clinical Data Characteristic Sex (female) Age, yr BMI Weight, kg Height, cm Left surgery side Comorbidities Hypertension Diabetes Smoking Diagnosis Ligament rupture Meniscus tear Chondral lesion
VR Group (n ¼ 24) 10 (41.67) 32.5 (15.0-62.0) 24.29 3.38 69.34 11.13 168.95 9.65 16 (53.33)
NR Group (n ¼ 24) 8 (33.33) 38.0 (20.0-65.0) 24.30 3.93 71.04 13.73 170.76 9.07 14 (46.7)
4 (16.67) 1 (4.17) 6 (25.00)
2 (8.33) 0 6 (25.00)
10 (41.7) 10 (41.7) 4 (16.6)
P Value .551* .190y .993z .640z .507z .551* .666x 1.000x 1.000* .423x
7 (29.2) 15 (62.5) 2 (8.3)
NOTE. Values are given as frequency (%), median (range), or mean standard deviation. NOTE. Test results are from *the c-squared test, ythe Wilcoxon ranksum test, z the t test, and xthe Fisher exact test. BMI, body mass index; NR, non-virtual reality; VR, virtual reality.
size calculation was performed based on the findings of Bekelis et al.22 With APAIS scores postulated to show a difference of 5.98 (95% confidence interval 4.90-7.04) between the VR and NR groups, the calculation showed that 24 cases would be needed in each group to reach an alpha value of 0.05 and a test power of 90%.
Results Demographic and clinical parameters including patient sex, age, body mass index, side of operation, comorbidities, and diagnosis were comparable between the 2 groups (P > .05) (Table 1). Regarding APAIS score, the sum S and sum C subscales showed significantly better outcomes in the VR group (median [interquartile range] for sum S ¼ 2.0 [2.0-4.0], median [quartile 1-quartile 3] for sum C ¼ 4.0 [4.0-8.5]) than in the NR group (median [interquartile range] for sum S ¼ 4.0 [3.0-5.0], median [quartile 1-quartile 3] for sum C ¼ 8.0 [5.3-9.8]) (P ¼ .014, P ¼ .005, respectively) (Table 2). Although the VR group also showed better outcomes in sum A and sum I in comparison to the NR group, the differences in outcomes between the 2 groups were not statistically significant (Table 2). Regarding VAS scores, preoperative measures showed significantly better outcomes in satisfaction among VR group patients (95 [90.0-100.0]) in comparison with NR group patients (85 [70.0-96.0]) (P ¼ .010). Although scores mostly showed better outcomes in the VR group, there were no significant differences in measures of pain, preparedness, and stress between the 2 groups. For postoperative VAS measures, the VR group (satisfaction score ¼ 95 [90.0-100.0], stress score ¼ 15 [2.5-37.5]) showed significantly better outcomes in satisfaction and stress in comparison with
the NR group (satisfaction score ¼ 85 [70.0-97.5], stress score ¼ 30 [30.0-50.0]) (Table 3) (P < .05). Postoperative VAS scores on pain were not significantly different between the 2 groups.
Discussion In this study, patients who experienced novel VR procedures preoperatively had improved anxiety around surgical encounters. Patients in the VR group were more satisfied and less stressed postoperatively. However, perioperative pain and preparedness were not affected by VR exposure. Anxiety is a feeling of nervousness or unease, which may be associated with hemodynamic symptoms. Preoperative anxiety begins as soon as a surgical schedule is given to a patient and increases to maximum intensity at the moment of hospital admission.23 Almost all patients experience some degree of anxiety when admitted for surgery, even when a surgery is considered “minor,” and there are numerous studies indicating that patients experience high levels of preoperative anxiety.2,13,24 The APAIS scale is a well-validated tool that assesses both preoperative anxiety and information need.21 The APAIS anxiety score has a cutoff point of 11, indicating that the patient is experiencing high-trait-anxiety requiring intervention. In this study, the APAIS anxiety score (sum C) was below the cutoff point of 11 in both groups, which can be interpreted as an indication that neither group is experiencing anxiety that requires further intervention, although a statistically significant difference exists between the groups. However, the APAIS information need scale (sum I) was higher than the cutoff point of 5 in the NR group, indicating that the patients needed more information about the topic of concern, although there was no statistically significant difference between the 2 groups. Misinformation or lack of information also affects anxiety in patients; therefore, preoperative preparation is very important to ensure the well-being of patients. Standard processes of preanesthetic assessment are intended to reassure patients by providing essential information before surgery. Klopfenstein et al.25 Table 2. APAIS Scores for Assessment of Preoperative Anxiety
Sum Sum Sum Sum
Subset A (range 2-10) S (range 2-10) I (range 2-10) C (range 4-20)
VR Group (n ¼ 24) 2.0 (2.0-3.0) 2.0 (2.0-4.0) 3.0 (2.0-6.7) 4.0 (4.0-8.5)
NR Group (n ¼ 24) 3.5 (2.0-4.0) 4.0 (3.0-5.0) 6.0 (4.0-6.0) 8.0 (5.3-9.8)
P Value .126 .005 .260 .014
NOTE. Values are given as median (interquartile range) for Sum A, S, I data or median (quartile 1-quartile 3) for Sum C data. Results from the Wilcoxon rank-sum test. APAIS, Amsterdam Preoperative Anxiety and Information Scale; NR, non-virtual reality; VR, virtual reality.
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Table 3. VAS Scores for Assessment of Perioperative Pain, Preparedness, Satisfaction, and Stress Factor Preoperative pain Preoperative preparedness Preoperative satisfaction Preoperative stress Postoperative pain Postoperative satisfaction Postoperative stress
VR Group (n ¼ 24) 30 (12.5-50.0) 90 (70.0-100.0) 95 (90.0-100.0) 40 (20.0-65.0) 30 (12.0-49.0) 95 (90.0-100.0) 15 (2.5-37.5)
NR Group (n ¼ 24) 30 (12.5-47.5) 80 (70.0-90.0) 85 (70.0-96.0) 50 (22.5-70.0) 30 (12.0-48.5) 85 (70.0-97.5) 30 (30.0-50.0)
P Value .358 .145 .016 .237 .265 .010 .012
NOTE. Values are given as median (interquartile range) or median (quartile 1-quartile 3). Results from the Wilcoxon rank-sum test. The higher the pain and stress score, the worse the outcome. The higher the preparedness and satisfaction, the better the outcome. NR, non-virtual reality; VAS, visual analog scale; VR, virtual reality.
studied the effects of preoperative anesthetic consultation before surgery and concluded that consultation preceding surgery in an outpatient clinic significantly reduced preoperative anxiety in patients. Informing and educating patients visually by showing the surgical procedures to which they will be subjected has also been shown to be effective in decreasing preoperative anxiety and increasing patient comprehension. Bayar et al.11 studied the effects of viewing live arthroscopic procedures on postoperative anxiety in 63 patients, finding that arthroscopic experience significantly decreased anxiety and worries about surgery, while increasing overall patient understanding and satisfaction. Most patients undergo MRI before arthroscopic knee surgery; however, it is not easy for a patient to fully understand the process by seeing a single section of an MRI for a limited time.16 To enhance patient understanding of 2D images on MRI, conversion of MRI to 3D images has been attempted by numerous researchers. Anastasi et al.26 reconstructed 3D knee images by volume-rendering techniques based on MRI to further enhance patient understanding of the anatomy of the human knee. Furthermore, Matsumoto et al.27 used 2D brain MRIs as inputs to reconstruct a 3D brain model that provides highly sophisticated views of the human brain. VR is a computer-generated simulation of a 3D image that can be interacted with in real or physical ways. VR has been used before surgery to reduce preoperative anxiety in patients. Bekelis et al.22 studied the effects of immersive preoperative VR on patient-reported outcomes in 127 patients undergoing cranial and spinal elective operations, finding that preoperative VR experiences led to increased satisfaction and decreased preoperative anxiety. Robertson et al.4 correlated preoperative anxiety with levels of pain, analgesic use, and length of hospital stay, finding that distraction via VR reduced self-reported anxiety levels in patients compared with standard (NR-distracted) care in patients before knee arthroscopic surgery. Mosso et al.12 studied the effects of immersive VR provided through a cell phone on reducing anxiety in patients undergoing ambulatory operations under local or regional
anesthesia, finding a significant reduction of anxiety after 45 minutes of operation in the VR group, but not in the nondistracted control group. Furthermore, Ganry et al.,13 in a prospective pilot study, showed that the VAS scores for stress and salivary cortisol levels were significantly reduced after application of immersive VR in patients with a score >11 on the APAIS anxiety and information scales. Limitations Our study has several limitations. First, patients and physicians were not blinded and were aware of study group assignments. However, a single assessor collecting outcome data was fully blinded to study group assignments, thereby minimizing the bias. Second, most of the patients enrolled in this study were relatively young, with an average age of 35.5 years. Thus, the outcomes of our study cannot be applied to elderly patients. Third, there was no standardization of preoperative information for the NR group. Fourth, as the sample size calculation was performed to determine the difference in APAIS anxiety score, other parameters (secondary outcomes) may lack statistical power in comparison. Fifth, although all patients underwent arthroscopic knee surgery, the location, chronicity, and extent of pathology varied between patients. Finally, correlation between preoperative anxiety and clinical outcomes was not studied.
Conclusions Application of preoperative VR experience of 3D reconstructed knee MRIs in patients undergoing arthroscopic knee surgery reduces anxiety around surgical encounters. The VR patient group was more satisfied overall and less stressed postoperatively. However, perioperative pain and preparedness were not affected by VR exposure.
References 1. Kiecolt-Glaser JK, Page GG, Marucha PT, et al. Psychological influences on surgical recovery. Perspectives from psychoneuroimmunology. Am Psychol 1998;53: 1209-1218.
VIRTUAL REALITY OF RECONSTRUCTED MRI 2. Wang SM, Kulkarni L, Dolev J, Kain ZN. Music and preoperative anxiety: A randomized, controlled study. Anesth Analg 2002;94:1489-1494. 3. Duggan M, Dowd N, O’Mara D, Harmon D, Tormey W, Cunningham AJ. Benzodiazepine premedication may attenuate the stress response in daycase anesthesia: A pilot study. Can J Anaesth 2002;49:932-935. 4. Robertson A, Khan R, Fick D, et al. The effect of virtual reality in reducing preoperative anxiety in patients prior to arthroscopic knee surgery: A randomised controlled trial. Presented at the 2017 IEEE 5th International Conference on Serious Games and Applications for Health (SeGAH), Perth, Australia, April 2017. 5. Aust H, Rüsch D, Schuster M, Sturm T, Brehm F, Nestoriuc Y. Coping strategies in anxious surgical patients. BMC Health Serv Res 2016;16:250. 6. Khatib Y, Madan A, Naylor JM, Harris IA. Do psychological factors predict poor outcome in patients undergoing TKA? A systematic review. Clin Orthop Relat Res 2015;473:2630-2638. 7. Ayral X, Gicquere C, Duhalde A, Boucheny D, Dougados M. Effects of video information on preoperative anxiety level and tolerability of joint lavage in knee osteoarthritis. Arthritis Rheum 2002;47:380-382. 8. Erkilic E, Kesimci E, Soykut C, Doger C, Gumus T, Kanbak O. Factors associated with preoperative anxiety levels of Turkish surgical patients: From a single center in Ankara. Patient Prefer Adherence 2017;11: 291-296. 9. Rossi MJ, Guttmann D, MacLennan MJ, Lubowitz JH. Video informed consent improves knee arthroscopy patient comprehension. Arthroscopy 2005;21:739-743. 10. Tou S, Tou W, Mah D, et al. Effect of preoperative 2-dimensional animation information on perioperative anxiety and knowledge retention in patients undergoing bowel surgery: A randomized pilot study. Colorectal Dis 2013;15:e256-e265. 11. Bayar A, Tuncay I, Atasoy N, Ayoglu H, Keser S, Ege A. The effect of watching live arthroscopic views on postoperative anxiety of patients. Knee Surg Sports Traumatol Arthrosc 2008;16:982-987. 12. Mosso JL, Gorini A, De La Cerda G, et al. Virtual reality on mobile phones to reduce anxiety in outpatient surgery. Stud Health Technol Inform 2009;142:195-200. 13. Ganry L, Hersant B, Sidahmed-Mezi M, Dhonneur G, Meningaud JP. Using virtual reality to control preoperative anxiety in ambulatory surgery patients: A pilot study
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in maxillofacial and plastic surgery. J Stomatol Oral Maxillofac Surg 2018;119:257-261. Subhas N, Patel SH, Obuchowski NA, Jones MH. Value of knee MRI in the diagnosis and management of knee disorders. Orthopedics 2014;37:e109-e116. Bossen JK, Hageman MG, King JD, Ring DC. Does rewording MRI reports improve patient understanding and emotional response to a clinical report? Clin Orthop Relat Res 2013;471:3637-3644. Mallikarjunaswamy MS, Holi MS, Raman R. Knee joint menisci segmentation, visualization and quantification using seeded region growing algorithm. J Med Imaging Health Inform 2015;5:552-560. Tongdee R, Narra VR, Oliveira EP, et al. Utility of 3D magnetic resonance imaging in preoperative evaluation of hepatobiliary diseases. HPB (Oxford) 2006;8:311-317. Klapan I, Vranjes Z, Prgomet D, Lukinovic J. Application of advanced virtual reality and 3D computer assisted technologies in tele-3D-computer assisted surgery in rhinology. Coll Antropol 2008;32:217-219. Fedorov A, Beichel R, Kalpathy-Cramer J, et al. 3D slicer as an image computing platform for the quantitative imaging network. Magn Reson Imaging 2012;30:1323-1341. Levoy M. Display of surfaces from volume data. IEEE Comput Graph Appl 1988;8:29-37. Moerman N, van Dam FS, Muller MJ, Oosting H. The Amsterdam Preoperative Anxiety and Information Scale (APAIS). Anesth Analg 1996;82:445-451. Bekelis K, Calnan D, Simmons N, MacKenzie TA, Kakoulides G. Effect of an immersive preoperative virtual reality experience on patient reported outcomes: A randomized controlled trial. Ann Surg 2017;265:1068-1073. Mitchell M. Patient anxiety and modern elective surgery: A literature review. J Clin Nurs 2003;12:806-815. Gillen E, Biley F, Allen D. Effects of music listening on adult patients’ pre-procedural state anxiety in hospital. Int J Evid Based Healthc 2008;6:24-49. Klopfenstein CE, Forster A, Van Gessel E. Anesthetic assessment in an outpatient consultation clinic reduces preoperative anxiety. Can J Anaesth 2000;47:511-515. Anastasi G, Bramanti P, Di Bella P, et al. Volume rendering based on magnetic resonance imaging: Advances in understanding the three-dimensional anatomy of the human knee. J Anat 2007;211:399-406. Matsumoto S, Asato R, Konishi J. A fast way to visualize the brain surface with volume rendering of MRI data. J Digit Imaging 1999;12:185-190.
Effects of Preoperative Virtual Reality Magnetic Resonance Imaging on Preoperative Anxiety in Patients Undergoing Arthroscopic Knee Surgery: A Randomized Controlled Study Jae-Hyuk Yang, M.D., Ph.D., Jae Joon Ryu, M.D., Eunwoo Nam, Ph.D., Hee-Suk Lee, A.S., and Jin Kyu Lee, M.D., Ph.D.
Purpose: To assess the effect of a preoperative virtual reality (VR) experience of 3-dimensional (3D) reconstructed magnetic resonance images (MRIs) on anxiety reduction in patients undergoing arthroscopic knee surgery. Methods: Patients in the VR group watched a 3D model of their own MRI through a VR headset describing the anatomy of the knee as well as their own lesion of interest for an arthroscopic procedure. Patients in the non-VR (NR) group received standard preoperative information about their MRI. The primary outcome for analysis was the Amsterdam Preoperative Anxiety and Information Scale score to measure level of anxiety and the need for information in patients undergoing arthroscopic knee surgery. Secondary outcomes were rated with visual analog scale (VAS) scores measuring patient pain, preparedness, satisfaction, and stress. Results: Regarding the Amsterdam Preoperative Anxiety and Information Scale score, the sum S (surgery-related anxiety) and sum C (combined anxiety component) subscales showed significantly better outcomes in the VR group (median [interquartile range] for sum S ¼ 2.0 [2.0-4.0], median [quartile 1-quartile 3] sum C ¼ 4.0 [4.0-8.5]) than in the NR group (median [interquartile range] for sum S ¼ 4.9 [3.0-5.0], median [quartile 1-quartile 3] sum C ¼ 8.0 [5.3-9.8]) (P ¼ .014 and P ¼ .005, respectively). Regarding VAS scores, preoperative measures showed significantly better outcomes in satisfaction among VR group patients (95 [90.0-100.0]) in comparison to NR group patients (85 [70.0-96.0]) (P ¼ .010). For postoperative VAS measures, the VR group (satisfaction score ¼ 95 [90.0-100.0], stress score ¼ 15 [2.5-37.5]) showed significantly better outcomes in satisfaction and stress in comparison to the NR group (satisfaction score ¼ 85 [70.0-97.5], stress score ¼ 30 [30.050.0]). Conclusions: Application of preoperative VR experience of 3D reconstructed knee MRIs in patients undergoing arthroscopic knee surgery reduces anxiety around surgical encounters. The VR patient group was more satisfied overall and less stressed postoperatively. However, perioperative pain and preparedness were not affected by VR exposure. Level of Evidence: Level I, randomized controlled trial.
See commentary on page 2400
S
urgery is a stressful event, and most patients admitted for surgery experience some degree of anxiety during the preoperative period.1,2 Preoperative anxiety may be influenced by multiple factors, including
patient age, sex, type of surgery, rapport with medical staff, previous experience or knowledge of surgical procedures, and personal characteristics and susceptibility to stressful situations.3,4 Most of the time, patients use
From the Department of Orthopaedic Surgery, Hanyang University Guri Hospital (J-H.Y.), Guri, Gyeonggi-do; Department of Orthopaedic Surgery, Hanyang University Hospital (J.J.R., J.K.L.), Seoul; Biostatistical Consulting and Research Laboratory, Hanyang University College of Medicine (E.N.), Seoul; and VRAD Inc., (H-S.L.), Seoul, Republic of Korea. The authors report the following potential conflicts of interest or sources of funding: The Ministry of SMEs and Startups provided funding for this research: C0515624. Full ICMJE author disclosure forms are available for this article online, as supplementary material. The trial was registered at ClinicalTrials.gov (a service of the U.S. National Institutes of Health), with a trial identification number of NCT03426163.
Received September 21, 2018; accepted February 17, 2019. Address correspondence to Jin Kyu Lee, M.D., Ph.D., Department of Orthopaedic Surgery, Hanyang University College of Medicine, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea. E-mail: [email protected] Ó 2019 Published by Elsevier on behalf of the Arthroscopy Association of North America 0749-8063/181152/$36.00 https://doi.org/10.1016/j.arthro.2019.02.037
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Arthroscopy: The Journal of Arthroscopic and Related Surgery, Vol 35, No 8 (August), 2019: pp 2394-2399
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VIRTUAL REALITY OF RECONSTRUCTED MRI
Fig 1. Consolidated Standards of Reporting Trials (CONSORT) flowchart.
coping mechanisms to regulate their emotions,5 but when distressing psychological symptoms are unchecked, these symptoms may have a negative impact on treatment results and recovery after surgery.6 A lack of education and misinformation regarding indicated surgical procedures have been suggested as significant factors that influence perioperative anxiety and patient compliance with treatment.7-10 Providing visualized information before surgical procedures has proved to reduce anxiety in various surgeries.7,11-13 Magnetic resonance imaging (MRI) allows physicians to provide patients with pathology information by showing the MRIs before scheduling surgery.14 Very often, however, it is not easy for a patient to fully understand the process by seeing a single section of an MRI for a limited time.15 Two-dimensional (2D) images presented in slices (e.g., axial, sagittal, and coronal), which patients view on monitors, often limit patients from visualizing the proper orientation of the knee. In light of this, attempts have been made to reconstruct 3D knee images by volume-rendering techniques based on MRI. Mallikarjunaswamy et al.16 used a volumerendering technique to reconstruct a 3D knee model following the segmentation of menisci from knee MRIs. 3D MRI has been shown to be helpful in evaluation and diagnosis of pathology, as 3D imaging allows demonstration of fine anatomic detail and manipulation of the images by removal or transparency of unwanted overlying structures, thus emphasizing the area of interest.17 Virtual reality (VR) is a technology that may further
enhance patient understanding of 3D models by allowing both physicians and patients to “fly” inside an imaginary body to understand the anatomy and indicated surgical procedures.18 The purpose of this study was to assess the effect of preoperative VR experience of 3D reconstructed knee MRIs on anxiety reduction in patients undergoing arthroscopic knee surgery. We hypothesized that patients presented with a preoperative VR experience of 3D reconstructed knee MRIs would show reduced anxiety in comparison with knee arthroscopic surgery patients undergoing a standard preoperative process.
Methods The institutional review board of the hospital at Hanyang University approved this study, and all patients provided informed consent. The trial was registered at ClinicalTrials.gov (a service of the U.S. National Institutes of Health). Patients Between January and June 2018, 61 patients expected to undergo elective arthroscopic knee surgery under general anesthesia were assessed for eligibility for this prospective, randomized controlled trial. Exclusion criteria were poor MRIs taken at other hospitals, diagnostic arthroscopic procedures without evident findings on MRI, arthroscopic procedures on both knees, osteoarthritic change (Kellgren-Lawrence grade 3), a history of surgery on a corresponding knee, and refusal
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to join the study. A total of 48 patients were enrolled in the study (Fig 1). Arthroscopic procedures were categorized into 3 groups: (1) cruciate ligament reconstruction surgery, (2) meniscus surgery (repair or meniscectomy), and (3) cartilage surgery (simple debridement or microfracture). Interventions Patients were randomized into 2 groups using a computer-generated random sequence. Randomization occurred during the clinic visit after the patient had agreed to undergo arthroscopic surgery and had signed consent to join the study. Because of the nature of the study, both patients and physicians were aware of study group assignments. However, the single assessor (J.J.R.) collecting the outcome data was blinded to the study group assignments. Group VR consisted of 24 patients (24 knees) set to receive a preoperative VR experience, whereas group non-VR (NR) consisted of 24 patients (24 knees) who were to receive standard preoperative information. Patients in the VR group watched a 3D model of their own MRIs through a VR headset (Vive; HTC, New Taipei City, Taiwan) describing the anatomy of the knee as well as their own lesion of interest in need of arthroscopic procedure. Patients in the NR group received standard preoperative information about their MRIs through a picture-archiving and communications system (p-viewer v. 5.0.8.1; Infinite, Seoul, Korea). All patients were provided with pathology information by viewing the MRIs before scheduling surgery at the outpatient clinic, and MRIs through either a VR headset or a picture-archiving and communications system were shown again to patients 1 day (w12 hours) before surgery during the time of preoperative counseling after patients were admitted to the hospital. All images were described by a single surgeon (J.K.L.) who was to perform the arthroscopic procedure. Visualization Process A trained researcher with expertise in 3D modeling segmented the knee MRIs of patients under the supervision of surgeons. Digital Imaging and Communications in Medicine images that consisted of >100 sagittal slices were used as inputs. Section thickness and intersection gaps were 3 and 0.3 mm, respectively. Software 3D Slicer 4.6.2 (Brigham and Women’s Hospital and The Slicer Community, Boston, MA) was used for segmentation, focusing primarily on structures including cruciate ligaments, menisci, cartilage, and collateral ligaments.19 After segmentation in the 3D Slicer, the Digital Imaging and Communications in Medicine file images were converted to .rnnd files to obtain a 3D array of data. Subsequently, surface extraction rendering processes were performed to obtain mesh (surface) data in the .obj file format.20
Software including Autodesk 3ds Max (Autodesk, San Rafael, CA) and ZBrush (Pixologic, Los Angeles, CA) were used to apply final feedback and to change the surface data. Finally, a reconstructed 3D model was exported as an .fbx file, including a texture map. Unreal Engine 4 software (Epic Games, Potomac, MD) was used to render reconstructed 3D models with realistic textures in head-mounted displays on HTC Vive viewers. Hand motion controllers were assigned to the 3D pointer models to provide a real-time tracking system (Video 1, available at www.arthroscopyjournal.org). Outcome Variables The primary outcome for analysis was Amsterdam Preoperative Anxiety and Information Scale (APAIS) score to measure level of anxiety and the need for information in patients.21 Patient APAIS scores were obtained preoperatively on the day of the surgical procedure. The APAIS scale is a validated self-reported instrument to assess preoperative patient anxiety. The questionnaire consists of 2 scales, an anxiety-related scale and an information-need scale related to the situation of waiting for surgery. The instrument has 6 items rated by the patient on a 5-point Likert scale. The APAIS anxiety scale is the sum of items 1, 2, 4, and 5, with a score range from 4 (lowest) to 20 (highest), and the APAIS information-need scale is the sum of items 3 and 6, with a score range from 2 to 10. Four subscales consist of (1) anesthesia-related anxiety (sum A, range ¼ 2-10), (2) surgery-related anxiety (sum S, range ¼ 2-10), (3) an information-need component (sum I, range ¼ 2-10), and (4) a combined anxiety component (sum C, range ¼ 4-20). A score >11 on the APAIS anxiety scale (sum C) indicates that the patient is experiencing anxiety requiring further intervention. Patients with a score of 5 or higher for the APAIS information-need scale (sum I) require information about topics of concern. The higher the score, the greater the degree of anxiety or need for additional information on the part of patients. Secondary outcomes were visual analog scale (VAS) scores (with a range of 0 [worst] to 100 [best]) measuring patient pain, preparedness, satisfaction, and stress. VAS scores were obtained twice preoperatively on the day of surgery and on postoperative day 3. The postoperative survey was identical to the preoperative survey except omitting items regarding preparedness. Statistical Analysis Statistical analysis was done with SPSS version 18.0 for Windows (SPSS, Chicago, IL). Data for VR and NR groups were compared statistically using the Student t test, the c-squared test, the Fisher exact test, and the Wilcoxon rank-sum test as appropriate. A value of P < .05 was regarded as significant. Sample size calculation was conducted before recruiting the patients. Sample
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VIRTUAL REALITY OF RECONSTRUCTED MRI Table 1. Patient Characteristics and Clinical Data Characteristic Sex (female) Age, yr BMI Weight, kg Height, cm Left surgery side Comorbidities Hypertension Diabetes Smoking Diagnosis Ligament rupture Meniscus tear Chondral lesion
VR Group (n ¼ 24) 10 (41.67) 32.5 (15.0-62.0) 24.29 3.38 69.34 11.13 168.95 9.65 16 (53.33)
NR Group (n ¼ 24) 8 (33.33) 38.0 (20.0-65.0) 24.30 3.93 71.04 13.73 170.76 9.07 14 (46.7)
4 (16.67) 1 (4.17) 6 (25.00)
2 (8.33) 0 6 (25.00)
10 (41.7) 10 (41.7) 4 (16.6)
P Value .551* .190y .993z .640z .507z .551* .666x 1.000x 1.000* .423x
7 (29.2) 15 (62.5) 2 (8.3)
NOTE. Values are given as frequency (%), median (range), or mean standard deviation. NOTE. Test results are from *the c-squared test, ythe Wilcoxon ranksum test, z the t test, and xthe Fisher exact test. BMI, body mass index; NR, non-virtual reality; VR, virtual reality.
size calculation was performed based on the findings of Bekelis et al.22 With APAIS scores postulated to show a difference of 5.98 (95% confidence interval 4.90-7.04) between the VR and NR groups, the calculation showed that 24 cases would be needed in each group to reach an alpha value of 0.05 and a test power of 90%.
Results Demographic and clinical parameters including patient sex, age, body mass index, side of operation, comorbidities, and diagnosis were comparable between the 2 groups (P > .05) (Table 1). Regarding APAIS score, the sum S and sum C subscales showed significantly better outcomes in the VR group (median [interquartile range] for sum S ¼ 2.0 [2.0-4.0], median [quartile 1-quartile 3] for sum C ¼ 4.0 [4.0-8.5]) than in the NR group (median [interquartile range] for sum S ¼ 4.0 [3.0-5.0], median [quartile 1-quartile 3] for sum C ¼ 8.0 [5.3-9.8]) (P ¼ .014, P ¼ .005, respectively) (Table 2). Although the VR group also showed better outcomes in sum A and sum I in comparison to the NR group, the differences in outcomes between the 2 groups were not statistically significant (Table 2). Regarding VAS scores, preoperative measures showed significantly better outcomes in satisfaction among VR group patients (95 [90.0-100.0]) in comparison with NR group patients (85 [70.0-96.0]) (P ¼ .010). Although scores mostly showed better outcomes in the VR group, there were no significant differences in measures of pain, preparedness, and stress between the 2 groups. For postoperative VAS measures, the VR group (satisfaction score ¼ 95 [90.0-100.0], stress score ¼ 15 [2.5-37.5]) showed significantly better outcomes in satisfaction and stress in comparison with
the NR group (satisfaction score ¼ 85 [70.0-97.5], stress score ¼ 30 [30.0-50.0]) (Table 3) (P < .05). Postoperative VAS scores on pain were not significantly different between the 2 groups.
Discussion In this study, patients who experienced novel VR procedures preoperatively had improved anxiety around surgical encounters. Patients in the VR group were more satisfied and less stressed postoperatively. However, perioperative pain and preparedness were not affected by VR exposure. Anxiety is a feeling of nervousness or unease, which may be associated with hemodynamic symptoms. Preoperative anxiety begins as soon as a surgical schedule is given to a patient and increases to maximum intensity at the moment of hospital admission.23 Almost all patients experience some degree of anxiety when admitted for surgery, even when a surgery is considered “minor,” and there are numerous studies indicating that patients experience high levels of preoperative anxiety.2,13,24 The APAIS scale is a well-validated tool that assesses both preoperative anxiety and information need.21 The APAIS anxiety score has a cutoff point of 11, indicating that the patient is experiencing high-trait-anxiety requiring intervention. In this study, the APAIS anxiety score (sum C) was below the cutoff point of 11 in both groups, which can be interpreted as an indication that neither group is experiencing anxiety that requires further intervention, although a statistically significant difference exists between the groups. However, the APAIS information need scale (sum I) was higher than the cutoff point of 5 in the NR group, indicating that the patients needed more information about the topic of concern, although there was no statistically significant difference between the 2 groups. Misinformation or lack of information also affects anxiety in patients; therefore, preoperative preparation is very important to ensure the well-being of patients. Standard processes of preanesthetic assessment are intended to reassure patients by providing essential information before surgery. Klopfenstein et al.25 Table 2. APAIS Scores for Assessment of Preoperative Anxiety
Sum Sum Sum Sum
Subset A (range 2-10) S (range 2-10) I (range 2-10) C (range 4-20)
VR Group (n ¼ 24) 2.0 (2.0-3.0) 2.0 (2.0-4.0) 3.0 (2.0-6.7) 4.0 (4.0-8.5)
NR Group (n ¼ 24) 3.5 (2.0-4.0) 4.0 (3.0-5.0) 6.0 (4.0-6.0) 8.0 (5.3-9.8)
P Value .126 .005 .260 .014
NOTE. Values are given as median (interquartile range) for Sum A, S, I data or median (quartile 1-quartile 3) for Sum C data. Results from the Wilcoxon rank-sum test. APAIS, Amsterdam Preoperative Anxiety and Information Scale; NR, non-virtual reality; VR, virtual reality.
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Table 3. VAS Scores for Assessment of Perioperative Pain, Preparedness, Satisfaction, and Stress Factor Preoperative pain Preoperative preparedness Preoperative satisfaction Preoperative stress Postoperative pain Postoperative satisfaction Postoperative stress
VR Group (n ¼ 24) 30 (12.5-50.0) 90 (70.0-100.0) 95 (90.0-100.0) 40 (20.0-65.0) 30 (12.0-49.0) 95 (90.0-100.0) 15 (2.5-37.5)
NR Group (n ¼ 24) 30 (12.5-47.5) 80 (70.0-90.0) 85 (70.0-96.0) 50 (22.5-70.0) 30 (12.0-48.5) 85 (70.0-97.5) 30 (30.0-50.0)
P Value .358 .145 .016 .237 .265 .010 .012
NOTE. Values are given as median (interquartile range) or median (quartile 1-quartile 3). Results from the Wilcoxon rank-sum test. The higher the pain and stress score, the worse the outcome. The higher the preparedness and satisfaction, the better the outcome. NR, non-virtual reality; VAS, visual analog scale; VR, virtual reality.
studied the effects of preoperative anesthetic consultation before surgery and concluded that consultation preceding surgery in an outpatient clinic significantly reduced preoperative anxiety in patients. Informing and educating patients visually by showing the surgical procedures to which they will be subjected has also been shown to be effective in decreasing preoperative anxiety and increasing patient comprehension. Bayar et al.11 studied the effects of viewing live arthroscopic procedures on postoperative anxiety in 63 patients, finding that arthroscopic experience significantly decreased anxiety and worries about surgery, while increasing overall patient understanding and satisfaction. Most patients undergo MRI before arthroscopic knee surgery; however, it is not easy for a patient to fully understand the process by seeing a single section of an MRI for a limited time.16 To enhance patient understanding of 2D images on MRI, conversion of MRI to 3D images has been attempted by numerous researchers. Anastasi et al.26 reconstructed 3D knee images by volume-rendering techniques based on MRI to further enhance patient understanding of the anatomy of the human knee. Furthermore, Matsumoto et al.27 used 2D brain MRIs as inputs to reconstruct a 3D brain model that provides highly sophisticated views of the human brain. VR is a computer-generated simulation of a 3D image that can be interacted with in real or physical ways. VR has been used before surgery to reduce preoperative anxiety in patients. Bekelis et al.22 studied the effects of immersive preoperative VR on patient-reported outcomes in 127 patients undergoing cranial and spinal elective operations, finding that preoperative VR experiences led to increased satisfaction and decreased preoperative anxiety. Robertson et al.4 correlated preoperative anxiety with levels of pain, analgesic use, and length of hospital stay, finding that distraction via VR reduced self-reported anxiety levels in patients compared with standard (NR-distracted) care in patients before knee arthroscopic surgery. Mosso et al.12 studied the effects of immersive VR provided through a cell phone on reducing anxiety in patients undergoing ambulatory operations under local or regional
anesthesia, finding a significant reduction of anxiety after 45 minutes of operation in the VR group, but not in the nondistracted control group. Furthermore, Ganry et al.,13 in a prospective pilot study, showed that the VAS scores for stress and salivary cortisol levels were significantly reduced after application of immersive VR in patients with a score >11 on the APAIS anxiety and information scales. Limitations Our study has several limitations. First, patients and physicians were not blinded and were aware of study group assignments. However, a single assessor collecting outcome data was fully blinded to study group assignments, thereby minimizing the bias. Second, most of the patients enrolled in this study were relatively young, with an average age of 35.5 years. Thus, the outcomes of our study cannot be applied to elderly patients. Third, there was no standardization of preoperative information for the NR group. Fourth, as the sample size calculation was performed to determine the difference in APAIS anxiety score, other parameters (secondary outcomes) may lack statistical power in comparison. Fifth, although all patients underwent arthroscopic knee surgery, the location, chronicity, and extent of pathology varied between patients. Finally, correlation between preoperative anxiety and clinical outcomes was not studied.
Conclusions Application of preoperative VR experience of 3D reconstructed knee MRIs in patients undergoing arthroscopic knee surgery reduces anxiety around surgical encounters. The VR patient group was more satisfied overall and less stressed postoperatively. However, perioperative pain and preparedness were not affected by VR exposure.
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