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ORIGINAL REPORTS

Surgical Skills Acquisition Among Left-Handed Trainees—True Inferiority or UnfairAssessment: A Preliminary Study

Jason Y. Lee, MD,* Phillip Mucksavage, MD,† and Elspeth M. McDougall, MD‡

*St. Michael’s Hospital, Division of Urology, University of Toronto, Toronto, Ontario, Canada; †PennsylvaniaHospital, Division of Urology, University of Pennsylvania, Philadelphia, Pennsylvania; ‡UCI Medical Center,

Department of Urology, University of California, Irvine, Orange, California

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INTRODUCTION: Studies involving the formal assessmentof surgical skills have often reported inferior abilities amongleft-handed surgical trainees (LHT). Most surgical training cur-ricula and assessment methods, however, are inherently gearedtoward right-handed trainees (RHT); potentially placing LHTat both a training and assessment disadvantage. We evaluatedthe effect of a hand dominance-based curriculum for acquisi-tion of basic suturing and knot tying skills among medicalstudents.

METHODS: After Institutional Review Board approval, first-and second-year medical students from the University of Cali-fornia, Irvine School of Medicine were recruited to participatein a basic suturing and knot tying skills course. Consentingstudents were randomized to either a left-handed curriculum ora right-handed curriculum consisting of (1) a 30-minute intro-ductory video and (2) a 2-hour instructor-led, hands-on train-ing session on basic suturing and knot tying. All instructionalmethods, instruments, and instructors were exclusively right-handed or left-handed for the right-handed curriculum or left-handed curriculum, respectively. Students were assessed on theperformance of 2 suturing tasks, continuous running suturingand instrument knot tying, and performance assessments wereconducted both immediately and 2 weeks posttraining.

RESULTS: A total of 19 students completed the trainingourse and both assessments (8 LHT, 11 RHT). Students ran-omized to a curriculum “concordant” with their hand domi-ance performed significantly better than those randomized to“discordant” curriculum on both tasks (p � 0.01). This dif-

erence was found at both immediate and 2 weeks posttrainingssessments. Within concordant and discordant groups, thereere no significant differences between LHT and RHT.

Correspondence: Inquiries to Jason Y. Lee, MD, FRCSC, Division of Urology, Departmentof Surgery, St. Michael’s Hospital, University of Toronto, 61 Queen St E – Suite 9-103,

pToronto, Ontario, Orange, Canada M5C 2T2; fax: �416 867 7433; e-mail: leejasoSMH@mail.com

Journal of Surgical Education • © 2012 Association of Program DirecPublished by Elsevier Inc. All rights res

CONCLUSIONS: This preliminary study demonstrates thatedical students, both LHT and RHT, immersed in a training

nvironment that is discordant with their hand dominanceight have inferior acquisition of basic suturing and knot tying

kills. (J Surg 70:237-242. © 2012 Association of Programirectors in Surgery. Published by Elsevier Inc. All rights re-

erved.)

KEY WORDS: medical education, handedness, motor skills,assessment

COMPETENCY: Medical Knowledge

INTRODUCTION

Left-handed (LH) individuals comprise approximately 10%-12% of the general population.1-3 Historically, it has not beeneasy for this minority group as they have long suffered unfairdiscrimination, living in a world designed for and often domi-nated by right-handed (RH) individuals. For example, the OldLatin word “sinistra” originally meant “left,” however, centuries-long cultural persecution of LH individuals has resulted in thenow more popular meaning of the Latin root, which connotes asense of “evil” or “wickedness.”

Demographic data suggest a disproportionately low numberof LH individuals among surgeons.4,5 When compared withother professionals, such as lawyers, architects, and mathemati-cians, surgeons have often been found to have the lowest prev-alence of LH individuals; even in comparison with other phy-sicians.4 Though the cause of this disparity is unknown, aommon explanatory theory alludes to a difference in innateanual dexterity between LH and RH individuals. If LH train-

es (LHT) truly lacked the technical aptitude required to be-ome successful surgeons, either on objective assessment or byelf-evaluation, it would follow then that they would be lessikely accepted into, or perhaps even pursue, a surgical training

rogram. However, is there truly a difference in innate manual

tors in Surgery 1931-7204/$30.00erved. http://dx.doi.org/10.1016/j.jsurg.2012.09.007

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skill between LHT and RH trainees (RHT), or is it once againa result of unfair discrimination?

LH individuals have traditionally been thought to possessincreased creativity and lateral thinking compared with theirRH counterparts, and less aptitude for visuospatial tasks4,6;considered by most to be an important skill set in the field ofsurgery. The evidence for decreased visuospatial ability amongLH individuals, however, is debatable at best and literature tothe contrary is becoming more common.4,6-11 Though contem-porary studies often note no significant differences between thesurgical skill of experienced LH and RH surgeons, supportingthe notion that minimal differences in visuospatial ability exist,many studies have found that novice LHT perform significantlyworse on surgical skills assessments.7,12-14 It has been well doc-

mented that the surgical environment is significantly biasedoward RH surgeons, not only from an operating perspective,ut a training and assessment perspective as well.15,16 Studies

have reported that LHT commonly encounter difficulties withRH trainers, with many reporting a belief that there were sig-nificant disadvantages to being an LH surgeon.1,2,16 In a studyby Adusumilli et al., 1 in 4 LH attending surgeons reported acertain degree of anxiety, as a direct result of their hand domi-nance, when initially entering into the surgical profession.2

In an attempt to better understand both the role of innatemanual dexterity between LHT and RHT and any hand dom-inance-related biases in traditional surgical training and assess-ment methods, our preliminary study examines the effect of ahand dominance-based training curriculum on novice surgicaltrainees’ acquisition of basic open suturing and knot tyingskills.

METHODS

First year medical students from the University of California,Irvine School of Medicine were invited, via an e-mail blast, toparticipate in an introductory course on basic open suturingand knot tying. After obtaining consent from interested stu-dents, a basic demographic questionnaire was administered toall participants. All students were then randomized to partici-pate in either an “LH curriculum” (LHC) or “RH curriculum”(RHC).

Regardless of whether randomized to the LHC or RHC, allstudents participated in 2 educational sessions on basic suturingand knot tying: (1) a 60-minute didactic lecture on core sutur-ing and knot tying concepts, followed by (2) a 2-hour hands-onsession providing students with an opportunity to learn andpractice various suturing and knot tying techniques.

The didactic lecture included an introduction to the in-struments required for suturing and knot tying, the varioussuture types used by surgeons, as well as the various suturingtechniques employed by surgeons. It also included a series ofvideos demonstrating proper suturing and knot tying tech-niques; holding and loading a needle driver, needle driving,instrument knot tying, simple interrupted suturing, contin-

uous running suturing, horizontal mattress suturing, vertical

238 Journal of S

mattress suturing, and subcuticular suturing. Faculty urolo-gists from the University of California, Irvine Medical Cen-ter served as instructors for the hands-on sessions, duringwhich each student was given both group and individualinstruction and feedback on the various suturing and knottying techniques introduced via video during the didacticlecture portion of the curriculum.

Though all students participated in the same standardizededucational sessions, those randomized to the LHC wereimmersed in a completely LH “environment” and those ran-domized to the RHC were taught in a completely RH “en-vironment.” During the didactic lecture, students in theLHC were shown videos of LH surgeons using LH instru-ments, employing only LH suturing and knot tying tech-niques; and vice versa for the RHC. An LH faculty memberled all LHC hands-on sessions and only LH instrumentswere made available to the LHC students; and vice versa forthe RHC. Though students randomized to a curriculum“discordant” with their own hand dominance (eg, RHT inthe LHC) were permitted to use either hand for thehands-on sessions, all instruction of suturing and knot tyingtechniques were demonstrated using the hand “concordant”with the curriculum to which they were randomized.

After completion of the didactic lecture and hands-on ses-sion, each student was assessed on their performance of 2 basictasks: (1) continuous running suturing (CRS) and (2) instru-ment knot tying (IKT). Student testing occurred at 2 timepoints after the course, both immediately after and 2 weeksposttraining, and involved a 6-point task checklist score (Fig. 1)and measurements of time to complete each task. Students werepermitted to use either hand for testing but the instrumentsmade available were always concordant with the curriculum towhich they were randomized. Each assessment was conductedby trained research assistants blinded to the hand dominance ofeach student.

Using SPSS Version 18.0, an independent samples Stu-dent t test was used to compare time scores and a Mann-Whitney U test was used to compare checklist scores. Cron-bach � calculation was used to examine reliability of ourssessment tool.

RESULTS

A total of 19 first-year medical students completed the basicsuturing and knot tying course, 8 LHT and 11 RHT. Five ofthe students were female (26%) and 9 students were random-ized to the LHC; both the LHC and RHC groups had 4 LHTeach. Sixteen of the students (84%) reported having only everseen surgical instruments or surgical videos before, with noactual hands-on surgical experience. Only 8 students (42%)reported an intention to pursue a career in surgery.

There were 9 students randomized to a “discordant” curric-ulum (eg, LHT in the RHC group, or vice versa), and 10students were in a “concordant” curriculum (eg, LHT in the

LHC group, or vice versa). Students in a “concordant” curric-

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ulum were found to perform significantly better than thoserandomized to a “discordant” curriculum (Table 1); mean timeto task completion (128.5 vs 177.4; p � 0.01; and 77.2 vs128.3; p � 0.01) and mean task checklist scores (U � 74.5; p �0.01; and U � 75; p � 0.01) were better in the “concordant”group for both the CRS and IKT tasks, respectively. Superiorperformance scores were seen in the “concordant” group at bothimmediate and 2-week postcourse assessments. Within the“discordant” group, there was no significant difference betweenLHT and RHT for all performance metrics. Similarly, no dif-ference between LHT and RHT was seen within the “concor-dant” group (Table 2).

Comparison of medical student assessments immediately af-ter the course and 2 weeks postcourse demonstrated no differ-ence on the CRS task on both time and task checklist score (p �0.65 and p � 0.89, respectively), though there was a trendoward worse completion times and checklist scores for the IKTask at 2 weeks postcourse (p � 0.09 and p � 0.07, respec-

tively). The reliability of the task checklist assessment tool was

FIGURE 1. Tra

acceptable with a Cronbach � of 0.82. i

Journal of Surgical Education • Volume 70/Number 2 • March/April

DISCUSSION

Fitts and Posner’s 3-stage theory of motor skill acquisitionhas served as a conceptual framework for educators andtrainers since it was introduced in the 1960s,17 and is widelyccepted in both the skills training literature and the surgicalducation literature.18,19 The theory outlines 3 dependent,et distinct, stages of learning that individuals encounterhile advancing from novice learner to that of a skilled

xpert. The first stage is the cognitive stage, which is charac-erized by novice learners focusing on specific intellectualasks (eg, Where does my hand go? How do I position theeedle driver? Which hand do I use to grasp the needle?). It

s during this initial stage that performance is erratic andross errors occur. Transition into the second stage of learn-ng, the associative stage, requires proper instruction, prac-ice, and feedback so the learners can consolidate their newnowledge of what, how, and when, into appropriate motorehavior. The final, autonomous phase of motor skill learn-

ssessment form.

ng is the result of extensive practice and consists of move-

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ments that are efficient, accurate, and require relatively littlemuscular energy; the learner demonstrates fluent and seem-ingly effortless motions when they attain this motor stage oflearning.

Whether formal or informal, objective or subjective, assess-ments of surgical potential and proficiency among surgicaltrainees often occurs during the transition period between thecognitive and associative stages of learning. Because the deter-minants of how long an individual remains in the cognitivephase are multifactorial, involving not only innate skill or abil-ity but also the quality and quantity of instruction, practice andformative feedback, trainees that are immersed in a learningenvironment which limits the number of new intellectual prob-lems are more likely to progress quickly to the associative stageof learning.

When novice LH surgical trainees are observed to have lowersurgical skills assessment scores compared with their RH col-leagues, it begs the question of whether there is actually a dif-ference in innate aptitude or whether it is a function of dealingwith an increased number of cognitive tasks, which slows the

TABLE 1. Medical Student Performance Scores Based on Curri

AssessmentConcordant Curricu

(mean � SD)

ImmediateCRS

Time (s) 128.5 � 30.4Checklist score (1–6) 5.1 � 1.1

IKTTime (s) 77.2 � 27.0Checklist score (1–6) 5.3 � 0.7

Two-WeekCRS

Time (s) 130.5 � 20.6Checklist score (1–6) 5.4 � 0.7

IKTTime (s) 79.1 � 27.5Checklist score (1–6) 5.0 � 1.1

CRS, continuous running suturing; IKT, instrument knot tying.

TABLE 2. Left-Handed Trainee (LHT) Versus Right-Handed Traine

Assessment LHT (mean � S

Concordant GroupCRS

Time (s) 127.5 � 17.0Checklist score (1–6) 5.0 � 0.8

IKTTime (s) 71.5 � 5.0Checklist score (1–6) 5.3 � 1.0

Discordant GroupCRS

Time (s) 184.3 � 18.3Checklist score (1–6) 4.0 � 1.2

IKTTime (s) 138.5 � 9.8Checklist score (1–6) 3.5 � 1.0

CRS, continuous running suturing; IKT, instrument knot tying.

240 Journal of S

process of skills acquisition and learning. The novice LH surgi-cal trainees not only have to learn new skills, but they oftenmust learn to do it with their nondominant hand. Studies onmotor skills learning have clearly demonstrated that beginners,in the early stages of learning, are inefficient at processing com-plex information.20-22

To better characterize the nature of this discrepancy, our pre-liminary study aimed to examine the role of hand dominance-based surgical training and assessment. Consistent with previ-ously published studies,7,12-14 our results demonstrated that

HT performed significantly worse in comparison with RHThen participating in a traditional right hand dominant train-

ng and assessment curriculum. However, LHT in a discordanturriculum were no different from RHT in a discordant curric-lum. This suggests that if the world were 90% “lefties,” andost training and assessment methods were left-hand domi-

ant, RHT would consistently score lower than their LHTolleagues. Our study also revealed that LHT in a concordanturriculum demonstrated similar performance scores to RHTn the traditional RHC, suggesting that the learning environ-

Discordant Curriculum(mean � SD) p

177.4 � 32.4 � 0.013.9 � .08 0.01

138.3 � 58.8 � 0.014.0 � 0.7 � 0.01

177.7 � 34.1 � 0.014.6 � 0.9 0.03

153.6 � 47.0 � 0.013.8 � 1.2 0.03

T) Performance Scores (Immediate)

RHT (mean � SD) p

129.2 � 10.2 0.855.2 � 0.8 0.75

81.0 � 9.1 0.105.3 � 0.8 0.89

172.0 � 11.2 0.253.8 � 0.8 0.77

138.2 � 6.3 0.964.4 � 0.9 0.20

culum

lum

e (RH

D)

urgical Education • Volume 70/Number 2 • March/April 2013

ment might play a larger role in skills acquisition than theinnate handedness of trainees.

In an interesting study by Torgerson and colleagues,23 inwhich they studied the effectiveness of teaching LHT to use anotologic drill designed for LH individuals, the authors foundthat RH medical students using standard RH otologic drills andRH drill burs learned bone drilling significantly better than LHmedical students using the same tools. However, similar to ourstudy results, the authors found that LH medical students usingLH tools learned bone drilling just as well as RH students usingRH tools.

In addition to the low number of participants, there are severallimitations to our preliminary study. Though attempts were madeto blind the trained raters from the hand dominance of each par-ticipant and the curriculum to which they were randomized, thisinformation could be deduced by close comparison of the hand-edness of the instruments provided and the hand used by eachparticipant for testing. Also, the task checklists have not been pre-viously validated; though there have been other published suturingassessment tools, based on the curriculum provided to our trainees,these tools were not aligned with our teaching techniques andtherefore were not used. Finally, the study included only medicalstudents who expressed interest in participating in the suturing andknot tying course, which could have introduced an element ofselection bias.

Further research into the effect, role, and feasibility ofhand dominance-based surgical training for novice traineesis required, however, this preliminary study sheds some lighton the need to consider hand dominance when teachingand, more importantly, assessing surgical skills among earlytrainees.

CONCLUSIONS

This preliminary study, examining the effect of hand domi-nance-based surgical training and assessment methods, demon-strates that students in a learning environment that is “discor-dant” with their innate hand dominance might have inferioracquisition of basic suturing and knot tying skills, regardless ofwhether LH or RH. Inferior skills assessments for LHT mightnot be a result of innate dexterity but rather the environment inwhich they are trained and assessed.

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