Sean Mackay

The use of electromagnetic motion tracking analysis to objectively measure open surgical skill in the laboratory-based model.

BACKGROUND Technical performance has traditionally been assessed subjectively within the operating theater, with few successful attempts at objective analysis. The Imperial College Surgical Assessment Device (ICSAD) has already been shown to be a valid quantitative measure of dexterity in laparoscopic surgical simulation. We describe its application to the assessment of open surgical procedures. STUDY DESIGN Fifty-one participants were recruited from four different levels of general surgical experience: basic surgical trainees (n = 12), junior specialist registrars (n = 13), senior specialist registrars (n = 13), and consultants (n = 13). They completed two tasks: a small bowel anastomosis and a vein patch insertion into an artery. Surgical performance was measured with the Imperial College Surgical Assessment Device, a motion analysis system that measures the number of hand movements made and time taken to complete a task. The four groups were compared statistically using the Kruskal-Wallis test (K-W). Pairwise group comparisons used the Mann-Whitney U test and p values were adjusted for multiple comparisons to determine the statistical significance of these comparisons. RESULTS Mean values for number of movements and time (secs) for small bowel anastomosis were 2,080/1,236 (basic surgical trainees), 1,673/1,016 (junior specialist registrars), 1,375/862 (senior specialist registrars), and 1,337/782 (consultants), respectively. Comparison of the medians by K-W revealed a p < 0.001 for each variable (No. of movements, time), respectively. Mean vein patch insertion results were 1,653/1,258, 1,297/1,006, 1,090/912, and 925/736 for each of the four groups. Again, comparison of the medians by K-W revealed a p < 0.001 for each variable. CONCLUSIONS These findings suggest that hand motion analysis may be an effective objective measure of dexterity in open surgical simulation.

Practice distribution in procedural skills training: a randomized controlled trial.

Background“Massed” and “distributed” practice are important concepts in the acquisition of fine motor skills, and may be important in training in procedural skills.MethodsA total of 41 novice subjects were recruited and randomized to three groups to receive training on the MIST VR surgical trainer. There were 14 subjects in each of groups A and B and 13 subjects in group C. Training comprised 20 min of massed practice for group A, 20 min of distributed practice in 5 min blocks for group B, and 15 min of distributed practice in 5-min blocks for group C. Following the training period, all groups had a 5-min rest period, followed by a 5-min retention test. Comparisons were made between groups A and B, and groups A and C.ResultsThere was a statistically significant difference between groups A and B (p= 0.023) on the retention test, with group B performing better. The increment between the groups was 19% for the overall score on MIST VR. There were also significant differences in the time taken to complete the task during the training phase (p=0.023, training blocks 3 and 4). Graphical representation suggests no effect between groups A and C, and statistical analysis confirms that the observed difference in median score is not significant.ConclusionThis study demonstrates a benefit for distributed practice over massed practice in learning laparoscopic surgical skills on the MIST VR surgical trainer. This finding has potential implications for skills training in all areas of medicine.

Recent advances in minimal access surgery

Minimally invasive surgery is the most important revolution in surgical technique since the early 1900s. Its development was facilitated by the introduction of miniaturised video cameras with good image reproduction. Laparoscopic cholecystectomy was the first procedure to be widely accepted, and several others are now well established. Other procedures are being validated, but further use of the technique may partly depend on the development of new enabling technologies. For example, a virtual reality laparoscopic simulator was recently used to assess the value of a three dimensional laparoscopic camera system.1 We present an overview of advances in minimal access surgery, concentrating on procedures that have most recently become established in everyday surgical practice. We selected the topics to be discussed after consultation with the other surgeons in our department. We then conducted a literature search (Medline 1993-2000) separately for each section of the paper. Because of the broad nature of the topics covered, we have generally cited good quality reviews rather than the original papers. Laparoscopy has been well established in gynaecology for many years, but the technique was adopted much more slowly in surgery. This is mainly because of the early limits of the technology. Gynaecologists used a purely optical telescope for illumination and visualisation and operated unassisted. With one hand on the telescope, the gynaecologist had only one hand to manipulate the viscera, and thus the technical repertoire was limited. The development of miniaturised television cameras that give an adequate image was key in the minimal access revolution. It allowed the assistant to have the same view as the surgeon. The assistant could therefore hold the camera (allowing the surgeon to operate with two hands) and retract the viscera to improve the access. Laparoscopic cholecystectomy was soon shown to be possible, and rapidly became the procedure of choice. …

The challenge of objective assessment of surgical skill

Technical performance in surgery has come under increased scrutiny in recent years, not least due to several highly publicized cases where it has been suggested that poor outcomes were the result of inadequate technical skill [1–3]. In the Bristol case, which involved a pediatric cardiac surgery unit, the concerns voiced by a member of medical staff have now resulted in disciplinary action against two surgeons by the General Medical Council, and a judicial inquiry, which is yet to hand down its report (www.bristol-inquiry.org.uk). The resulting debate, both public and within the profession, has focused on the need for objective and independent assessment of surgical skill, and a significant research interest has developed in this area.

The PreOp flexible sigmoidoscopy trainer

AIM: To demonstrate face and construct validity of a computer based flexible sigmoidoscopy trainer. METHODS: The PreOp (Immersion Medical, USA) system is a virtual reality based flexible sigmoidoscopy simulator. The system records several performance parameters, such as percentage of colonic mucosa visualized, time taken, and pathlength of endoscope travel. Forty-five subjects were divided into three groups: novice (never performed a lower GI endoscopy), intermediate (5–50 examinations), and trained (greater than 200 examinations). After initial familiarization subjects were assessed three times on a case module. Results showed a nonparametric distribution. RESULTS: There was a significant difference between all three groups with respect to percentage of mucosa visualized (novice 71.0 ± 3.7%, intermediate 77.3 ± 5.6%, expert 84.8 ± 4.6%, Kruskal–Wallis p <0.001) and efficiency ratio (%mucosa/time, novice 0.163 ± 0.055, intermediate 0.259 ± 0.07, expert 0.306 ± 0.058, p <0.001). The novice group was also slower and had a lower pathlength of instrument travel compared to the others. CONCLUSION: PreOp virtual reality simulator is a valid discriminator of flexible sigmoidoscopic experience. Its effect on training needs to be explored.

Electromagnetic motion analysis in the assessment of surgical skill: Relationship between time and movement

Introduction:  Electromagnetic motion analysis is a promising method of assessing surgical skill in a skills‐laboratory setting. There is a very strong correlation between movement and time data, and this study was conducted to determine whether this relationship is fixed, or whether it can vary.

Motion Analysis in the Assessment of Surgical Skill

Abstract Manual skill is now widely recognised as an important aspect of training in surgery. However, measurement of the skill of a surgeon has in the past been rather subjective in nature, relying on the judgement of experts in the analysis of videotapes. Objective measurements can be made by analysing the velocities of a surgeons hands during a procedure. In particular, we have found that the number of movements made during a typical procedure will decrease as the surgeons skill increases. Velocity traces display purposeful movements corrupted by uncorrelated noise from sources such as hand tremor and measurement artefacts. However, we have found that it is possible to filter the noise effectively. Furthermore, we have shown that the skill measurement obtained by counting movements is highly robust to over or under filtering.