Randomized Comparison of Straight Versus Articulating Instruments for Single-Incision Laparoscopy (SIL)

Byron F Santos, MD, Taylor J Reif, BS, Nathaniel J Soper, MD, Eric S Hungness, MD. Northwestern University Department of Surgery, Chicago, IL.

Introduction: The increased technical difficulty of SIL compared to conventional laparoscopy raises concerns about its safety, and remains a barrier to widespread adoption. Novel instruments have the potential to improve SIL performance, but may come at an increased cost. We conducted a randomized comparison of SIL performance using conventional, straight laparoscopic instruments versus instruments capable of dynamic articulation using a previously validated SIL simulator.

Methods: Medical students were recruited for the study in accordance with an IRB-approved protocol. The subjects were randomized to use either straight or articulating instruments during a standardized, distributed training period consisting of 4 sessions. Subjects performed peg transfer (PEG) and pattern cutting (CIRCLE) tasks from the Fundamentals of Laparoscopic Surgery (FLS) using an FLS box trainer modified to accept a Covidien SILS Port ™ with two working ports for instruments and one port for a 30-degree 5mm laparoscope. Subject performed the tasks using either two straight instruments or one straight instrument plus a disposable, articulating instrument in the dominant hand. Scores were recorded at baseline and after completion of the training period. Performance of FLS tasks was graded using standard time and accuracy metrics. Individual task scores were calculated for each participant, and normalized to previously published FLS scoring criteria used to distinguish competent (>54%) and non-competent surgeons (<54%).

Results: A total of 25 subjects completed the training period and were included in the analysis. Baseline scores for both tasks were low and similar between groups. All scores improved significantly over the training period. There was no statistically or clinically significant difference in the final scores between groups.

Table 1. Performance (%) According to Instrument Type and Training
Straight (n=13)Articulating (n=12)p – value
PEGBaseline27 ± 3119 ± 240.48
Post-training79 ± 16*76 ± 17*0.74
CIRCLEBaseline5 ± 121 ± 40.34
Post-training45 ± 21*32 ± 20*0.14
* P-value < .001 for improvement from Baseline to Post-training.

Conclusion: SIL performance improves with simulator training. Dynamic articulating instruments for SIL do not confer a performance advantage either at baseline or after a period of distributed training. Given their added cost, use of dynamic articulating instruments for clinical SIL should be selective and preceded by simulator training.

Session: SS10
Program Number: S050

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