Improvement of arthroscopic surgical performance using a new wide-angle arthroscope

Background We have developed a new arthroscope with a field of view of 150°. This requires less motion to maneuver, and the optical error is decreased. It also improves how novices learn arthroscopy. We hypothesized that surgical performance using this arthroscope is superior to a conventional arthroscope. This study tested the hypothesis using motion analysis and a new validated parameter, “dimensionless squared jolt” (DSJ). Methods We compared the surgical performance using between the wide-angle and the conventional arthroscope among 14 novice orthopedic residents who performed three standardized tasks three times with each arthroscope. The tasks simulated arthroscopic rotator cuff repair surgical skills. Their motion was analyzed using an optical tracking system. The differences in performance parameters, such as time taken, average acceleration of the hands (m/s2), the number of movements, and the total path length (m) including DSJ between the two arthroscopes, were investigated using paired t-tests. Results All the estimated values for the tasks using the 150° arthroscope were lower than those for the 105° arthroscope. There were statistically significant differences in performance between the two arthroscopes only for DSJ (p = 0.014) and average acceleration (p = 0.039). Conclusions DSJ and average acceleration are reliable parameters for representing hand-eye coordination. The surgical performance of novice arthroscopists was better with the new wide-angle arthroscope than with the conventional arthroscope.


INTRODUCTION
42 Shoulder arthroscopy has evolved and has become an important tool for minimally invasive 43 surgery. As arthroscopic techniques have evolved, arthroscopy has become the gold standard 44 for diagnosis and management of shoulder disorders [1][2][3][4]. However, several issues remain, 45 particularly with regards to the long learning curve and demands on the time required for 46 training. Additionally, technical errors arise from the technical errors arising from the 47 limitations of hand-eye coordination required for arthroscopic systems, especially for novice 48 arthroscopists. Several studies have shown that training using a dry or virtual simulator is 49 effective and safe for overcoming these issues [5][6][7]. However, cost-effectiveness remains a 50 limitation of every training hospital.

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Based on our experience, one of the main issues in arthroscopy is the limited field of 52 view (FOV) of conventional arthroscopic systems. Several studies have reported that a 53 limited arthroscopic FOV can make it difficult to identify entire anatomic structures; this was 54 often associated with poor hand-eye coordination regarding surgical triangulation and 55 handling the instrument [8][9][10][11]. We hypothesized that a wide-angle arthroscope with a better 56 FOV would result in better hand-eye coordination and would bring important benefits such as 57 an accelerated learning technique, reduction of technical errors, and improvement in the long-58 term performance of surgical skills.

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The aim of this study was to compare hand-eye coordination and the performance of 60 surgical skills between a newly developed wide-angle arthroscope (150° FOV) and the 61 conventional arthroscope (105° FOV). We used motion analysis to evaluate the performance 62 of novice arthroscopists, assessing their hand-eye coordination by using the "dimensionless 63 squared jolt" (DSJ), which is widely accepted as an objective parameter of hand-eye 64 coordination in the field of engineering. 78 participant was given an instructional video manual that covered all the experimental 79 processes and arthroscopic tasks to be performed, as well as an introduction to the 80 experimental and surgical instruments. The participants were allowed 10 minutes to become 81 familiar with the experimental system and surgical instruments. The participants performed 82 the tasks without any assistance.

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A dry right shoulder model (Arthrex, Naples, FL, USA) was used for the tasks (Fig   84 2a). Black nylon sutures were made at five sites along the lateral border of the rotator cuff, 85 and the bicipital groove was marked in blue. A pilot hole for an anchor was made at an 86 appropriate position on the greater tuberosity (Fig 2b). The model and related instruments 87 were set up on a table, with a pair of reflective hand illustrations placed on the table to mark 88 the start and end positions for the participants (Fig 4b).
The three assigned tasks, which simulated basic surgical techniques, were as follows: 90 (a) touching the five points along the rotator cuff marked by sutures twice using the grasper, 91 passing through the anterior portal; (b) inserting an anchor at the predetermined point on the 92 footprint of the rotator cuff; and (c) pulling the suture through the anterior portal using the 93 grasper (Fig 3a-3c). These three tasks have been validated by previous studies [6,[13][14][15].
94 Each task was performed three times with each scope. 99 OR, USA) (Fig 4a), 10-mm reflective marker balls placed on the third metacarpal area of the 100 dorsal side of participant's hands, and tracking software (Motive: Tracker; Natural Point, 101 Inc.) (Fig 4b).
The system continuously recorded three-dimensional (3D) data for the two   130 DSJ (p=0.014) and average acceleration (p=0.039) were the only parameters which showed a 131 statistically significant difference between the two arthroscopes. There were no other 132 statistically significant differences between the arthroscopes, including the time taken 133 (p=0.282), the number of movements (p=0.323), or total path length (p=0.142). All other 134 estimated values for the tasks using the 150° arthroscope were lower than those for the 105° 135 arthroscope. The collected data are summarized in Table 1 and Figure 5.

152
To overcome this subjective limitation, we tried to objectively find the tool to assess 153 hand-eye coordination, which is highly related to the surgical performance. Fortunately, 154 motion tracking systems make it possible to obtain objective data regarding hand movements 155 [14, 27-30]. Using the motion tracking system, we evaluated the participants' performance 156 and hand movements by the time taken to complete the tasks, the total path length traveled by 157 their hands, the number of movements made, and the average acceleration of the hands. From 158 these, we calculated DSJ, a relatively simple indication of movement quality. A "jolt," also 159 known as a "jerk," is a physical value indicating the rate of change of acceleration for a