Abstract
Purpose
There are no controlled prospective studies evaluating the effect of dominant handedness in left- and right-sided surgery in otolaryngology. Endoscopic microlaryngeal phonosurgery is an ideal procedure to assess technical aspects of handedness and laterality, due to anatomic symmetry. In this study, we analyzed (1) choice of surgical approach and (2) outcomes based on handedness and laterality in a microlaryngeal simulator.
Methods
Using a validated high-fidelity phonosurgery model, a prospective cohort of 19 expert laryngologists undertook endoscopic resection of a simulated vocal fold lesion. These resections were video-recorded and scored by 2 blinded expert laryngologists using a validated global rating scale, procedure-specific rating scale, and a hand preference analysis.
Results
There were 18 right-handed participants and 1 left-handed. 12 left and 7 right excisions were evaluated. Cronbach’s alpha for inter-rater reliability was good (0.871, global scale; and 0.814, procedure-specific scale). Surgeons used their dominant hand 78.9% of the time for both incision and dissection. In cases where the non-dominant hand would have been preferred, surgeons used the non-dominant hand only 36.4% of the time for incision and dissection. Use of the non-dominant hand did not influence global or procedural rating ( p = 0.132 and p = 0.459, respectively).
Conclusions
In this simulation of microlaryngeal surgery, there were measurable differences in surgical approaches based on hand dominance, with surgeons preferring to cut and perform resection with the dominant hand despite limitations in the instrumentation and exposure. Regardless of hand preference, overall outcomes based on global rating and technique specific rating scales were not significantly different.
1
Introduction
Innate human handedness affects the use of surgical instruments particularly in narrow-field surgery and may be relevant in surgical resident education . Endoscopic microlaryngeal phonosurgery is an ideal procedure for assessing the technical aspects of handedness. Anatomically, there is relative symmetry between sides of the larynx, and given the inherent restraints of a laryngoscope and long-handled instrumentation, hand choice is often dictated by the laterality of the lesion rather than innate handedness or surgeon preference, and crossing one’s hands or instruments could potentially lead to sub-optimal microsurgery. Unlike in open surgery, an endoscopic surgeon cannot easily adjust her body position to optimize maneuverability . Two-handed technique is required for all but the simplest of endoscopic laryngology procedures.
There has been significant investigation into handedness in the general surgery literature, particularly related to the rise of robotic surgery . There have been no controlled prospective studies demonstrating and evaluating the outcomes of left- and right-handed surgery in laryngology, although handedness has been studied in other surgical specialties involving the head and neck .
Simulation has become an integral component of both assessing and developing surgical skills. Furthermore, it affords a controlled environment in which to assess the choices surgeons make (and the resulting outcomes) based on factors like innate handedness and lesion laterality. In this study, a validated laryngeal simulator was used to evaluate the choice of surgical approach to right- or left-sided lesions and, secondly, evaluate the possible effect of handedness using a global and procedure specific rating scale.
2
Methods
Approval of this study was obtained through the Massachusetts Eye and Ear Institutional Review Board (IRB). We utilized a high-fidelity porcine phonosurgery model, which has been described and validated previously . Expert fellowship-trained laryngologists were asked to watch a standardized instructional video at the start of the session. Participants indicated their innate handedness by paper survey. The participants were then asked to undertake an endoscopic resection of a vocal fold lesion, simulated by brown silicone II (General Electric, Fairfield, Connecticut) injected in a subepithelial fashion and cured at 4 degrees Celsius (see Fig. 1 A ). These simulated lesions were placed at a depth of approximately 2 mm. Assignment of left or right lesions was made randomly. The participants were instructed to make a single incision, raise a microflap, excise the lesion, and redrape the microflap at the end of the procedure. The procedures were video-recorded using high-definition cameras and stored in an anonymous fashion.
Two blinded laryngologists then scored each dissection video using a previously validated global rating scale (encompassing ratings for “Respect for Tissue,” “Time and Motion,” “Instrument Handling,” “Flow of Operation,” and “Knowledge of Procedure” rated on a 1 [worst] to 5 [best] scale, with maximum score of 30), as well as a procedure-specific rating scale (which included grades for exposure, incision/microflap, dissection, complete removal, and final appearance on a 1 [worst] to 5 [best] scale, with maximum score of 35) . Hand preference during the procedure (regardless of reported handedness) was defined as using the right or left hand greater than 50% of the procedure time. Reviewers made note of participants for whom the hand performing the dissection (rather than assisting) was on the ipsilateral side to the lesion (i.e., left-handed dissection for a left-sided lesion). Fig. 1 B is an example of such a resection, whereas Fig. 1 C does not.
Review was done over a one-month period in August 2016. Data analysis, including measures of inter-rater reliability and non-parametric tests of significance, was performed using Microsoft Excel (Redmond, WA) and JMP 12 Pro software (Cary, NC). Significance was defined at a p value of 0.05.
2
Methods
Approval of this study was obtained through the Massachusetts Eye and Ear Institutional Review Board (IRB). We utilized a high-fidelity porcine phonosurgery model, which has been described and validated previously . Expert fellowship-trained laryngologists were asked to watch a standardized instructional video at the start of the session. Participants indicated their innate handedness by paper survey. The participants were then asked to undertake an endoscopic resection of a vocal fold lesion, simulated by brown silicone II (General Electric, Fairfield, Connecticut) injected in a subepithelial fashion and cured at 4 degrees Celsius (see Fig. 1 A ). These simulated lesions were placed at a depth of approximately 2 mm. Assignment of left or right lesions was made randomly. The participants were instructed to make a single incision, raise a microflap, excise the lesion, and redrape the microflap at the end of the procedure. The procedures were video-recorded using high-definition cameras and stored in an anonymous fashion.
