Analysis of hand motion differentiates expert and novice surgeons

doi:10.1016/j.jss.2013.12.009

Journal of Surgical Research

Volume 188, Issue 1, 1 May 2014, Pages 8-13

https://doi.org/10.1016/j.jss.2013.12.009 Get rights and content

Abstract

Background

The number of operations performed by a surgeon may be an indicator of surgical skill. The hand motions made by a surgeon also reflect skill and level of expertise. We hypothesized that the hand motions of expert and novice surgeons differ significantly, regardless of whether they are familiar with specific tasks during an operation.

Methods

This study compared 11 expert surgeons, each of whom had performed >100 laparoscopic procedures, and 27 young surgeons, each of whom had performed <15 laparoscopic procedures. Each examinee performed a specific skill assessment task, in which instrument motion was monitored using magnetic tracking system. We analyzed the paths of the centers of gravity of the tips of the needle holders and the relative paths of the tips using two mathematical methods of detrended fluctuation analysis and unstable periodic orbit analysis.

Results

Detrended fluctuation analysis showed that the exponent in the function describing the initial scaling exponent (α₁) differed significantly for experts and novices, being close to 1.0 and 1.5, respectively (P < 0.01). This indicated that the expert group had a greater long-range coherence with an intrinsic sequence and smooth continuity among a series of motions. Likewise, unstable periodic orbit analysis showed that the second period of unstable orbit was significantly longer for experts in comparison with novices (P < 0.01). This demonstrates mathematically that the hands of experts are more stable when performing laparoscopic procedures.

Conclusions

Objective evaluation of hand motion during a simulated laparoscopic procedure showed a significant difference between experts and novices.

Introduction

Although laparoscopic surgery has many advantages, such as decreased scarring, faster recovery, and cosmetic advantages, laparoscopic surgical skills may be harder to learn for some surgeons, and in some ways differ from the techniques used in conventional open surgery. Specialized training is important and necessary for surgeons to perform laparoscopic surgery safely and accurately.

The number of operations performed by a surgeon is sometimes considered an indicator of surgical skill, and surgeons who have performed many operations are considered “expert surgeons.” In addition to facilitating the safe and efficient conduct of an operative procedure, experience enables surgeons to seek strategic remedies when faced with difficulties during an operation. The hand motions made by a surgeon during an operation may also reflect the skill of a surgeon. It is sometimes said that surgeons seek “economy of motion” in reference to manipulating surgical instruments, but measuring this desirable trait is a complex matter. We hypothesized that the hand motions of expert surgeons differ significantly from those of novice surgeons, regardless of whether the expert surgeons are familiar with the specific tasks during a particular operation.

Ordinarily, expert surgeons are distinguished from novice surgeons by performance scores, which are based on performance time, the speed with which instruments are manipulated, and the number of errors made during an operation. Performance scores are frequently used to assess surgeons being trained to perform laparoscopic procedures [1], [2], [3], [4] and have been used to distinguish experts from novices in the conduct of laparoscopic procedures. Performance scores alone, however, cannot assess the skills required for laparoscopic surgery. Other measures that may distinguish expert from novice surgeons being trained in laparoscopic procedures include psychomotor skills and eye–hand coordination [5], [6], [7], [8], [9], [10], [11], although these factors alone are neither necessary nor sufficient for distinguishing the skills of expert and novice surgeons in performing laparoscopic procedures.

The goal of this study was to identify latent factors possessed by experts in the conduct of laparoscopic procedures. Kinematic analysis of the motions made by a surgeon's forceps during a skill assessment task were evaluated, and two mathematical analysis techniques used to assign numerical values to features of surgical performance such as “fluctuation” and “unstable periodic orbits,” which may at least in part describe the concepts attributed to “economy of motion.”

Section snippets

Study participants

Participants in this study included 38 surgeons who have taken a laparoscopic surgery training course held at Kyushu University Training Center for Minimally Invasive Surgery [1], [12], [13]. Examinees were divided into two groups. The expert group included 11 expert surgeons, each of whom had performed >100 laparoscopic surgical procedures and completed the skill assessment task, and the novice group had 27 young surgeons, each of whom had performed <15 laparoscopic surgeries and had not

Detrended fluctuation analysis

We applied detrended fluctuation analysis to the center movement of both hands for all 38 participants. Figure 3A shows the plot for the initial scaling exponent, α₁. The exponent α₁ was significantly higher for the novice than for the expert group (P < 0.01), with α₁ for the novice group being about 1.5 and that for the expert group about 1.0 (1/f), indicative of Brown noise (i.e., no correlation). These results indicate that the expert group, with a lower value of α₁ was closer to “long-range

Discussion

The number of operations performed by a surgeon is sometimes considered an indication of surgical skill, and surgeons who perform large numbers of a particular type of surgery are often referred to as “expert surgeons” [18], [19], [20]. We have defined expert surgeons as those who previously performed >100 laparoscopic procedures. The aim of this study was to identify the unique characteristics of expert surgeons through a mathematical analysis of hand motion. We have applied mathematical

Conclusions

These mathematical analyses provide a new way of quantitative differences in the hand motions of expert and novice surgeons during a simulated laparoscopic procedure. Further studies of these analytic techniques are indicated, and may provide a useful tool in both training and assessment of future laparoscopic surgeons.

Acknowledgment

Drs Uemura, Tomikawa, Kumashiro, Miao, Sozaki, Ieiri, Ohuchida, Lefor, and Hashizume have no conflicts of interest or financial ties to disclose.

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EducationAnalysis of hand motion differentiates expert and novice surgeons

Abstract

Background

Methods

Results

Conclusions

Introduction

Section snippets

Study participants

Detrended fluctuation analysis

Discussion

Conclusions

Acknowledgment

Am J Surg

J Surg Res

J Am Coll Surg

Gait Posture

J Am Coll Surg

Development of an objective endoscopic surgical skill assessment system for pediatric surgeons: suture ligature model of the crura of the diaphragm in infant fundoplication

Pediatr Surg Int

A computer-based laparoscopic skills assessment device differentiates experienced from novice laparoscopic surgeons

Surg Endosc

Scientific assessment of endoscopic surgical skills

Minim Invasive Ther Allied Technol

Perceptual impairment and psychomotor control in virtual laparoscopic surgery

Surg Endosc

Construct validity for eye-hand coordination skill on a virtual reality laparoscopic surgical simulator

Surg Endosc

Transfer validity of laparoscopic knot-tying training on a VR simulator to a realistic environment: a randomized controlled trial

Surg Endosc

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Surg Endosc

A study of psychomotor skills in minimally invasive surgery: what differentiates expert and nonexpert performance

Surg Endosc

Effectiveness of endoscopic surgery training for medical students using a virtual reality simulator versus a box trainer: a randomized controlled trial

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Education
Analysis of hand motion differentiates expert and novice surgeons