Most everyone has seen the auto-insurance TV ad where the deep-voiced man asserts, “Safe drivers save 40%.” Insurance savings notwithstanding, patients frequently ask orthopaedic surgeons when they can return to safe driving after surgery. Of course, the answer depends partly on the patient’s ability to drive safely before surgery, but most of the orthopaedic research on this topic has focused on lower extremities. In the September 16, 2020 issue of The Journal, Orfield et al. take a detailed look at the driving question after wide-awake, local-anesthetic, no-tourniquet (WALANT) surgery of the hand.
Twelve right-handed patients drove 18 miles under baseline conditions and completed various parking tasks during the first 45- to 55-minute test. The instrumented vehicle they drove obtained kinematic data automatically, and behavioral responses were recorded on video cameras. Then the same subjects completed the same driving exercise in the same vehicle—but this time after having their right hand injected with 10 mL of 1% lidocaine over the volar wrist, and another 10 mL into the carpal tunnel. To further simulate WALANT conditions, researchers applied a bulky hand dressing to each participant’s right hand. The WALANT-modeled driving test included a simulated “surprise event” that required avoidance maneuvers. Researchers analyzed before-and-after data on a variety of kinematics, including braking, acceleration, right and left turning, and proportion of time spent driving with each or both hands.
Overall, Orfield et al. found no evidence of a negative impact on driving fitness in the simulated WALANT state. In fact, the subjects braked harder and steered more smoothly in the WALANT-modeled state, an indication that they perceived they might be impaired. Not surprisingly, participants in the WALANT-modeled state spent decreased time using both hands (from 72% to 62%), while left-hand-only driving increased from 2% to 16% of the time. All participants reported that they felt safe to drive with a numb, bandaged right hand.
These noninferiority findings suggests that WALANT patients are no worse off with immediate driving after the surgical procedure than they were beforehand. The authors are quick to point out that these findings should not be generalized beyond right-handed people driving a passenger car with an automatic transmission in the United States. Still, this study gives us some evidence-based data to better inform patients undergoing common hand procedures now frequently performed under WALANT conditions, such as trigger-finger and carpal-tunnel release. However, we can’t guarantee they will save on their auto insurance.
Click here to view a 3-minute “Author Insight” video with study co-author Peter J. Apel, MD, PhD.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
The work of Orfield et al in essence is an assessment of how good a group of Right Handed Dominant (RHD) drivers are at driving when their right hand is not as available as it normally would be.
It should be no surprise that left hand only use would be increased, although the interesting part is that this is at the expense of the duration of both hand use, rather than right hand only use. Another interesting observation is that the participants had both hands on the wheel most of the time (at least 62%) rather than one hand (and right hand, I would have expected of RHD), as well as the fact that normally pre-WALANT, the RHD drivers used left hand only driving (15.6%) longer than right hand only driving (11.7%).
It is of course possible that a significant amount of the time taken to complete the 45-55 minute 29-mile course involves specific low speed, high precision maneuvers including various forms of parking, but nevertheless one would conclude all of these study participants exhibit recommended driving posture using both hands most of the time even when cruising; I cannot confirm that Australian drivers do this!
There is, however, a need to be cautious about these findings. The authors used 1% lidocaine buffered with 8.4% sodium bicarbonate without epinephrine; hence the expected anaesthetic duration is between 30 and 120 minutes. In this study the authors demonstrated some numbness hence anaesthetic effect persisting in all patients after the 45-55 minutes of driving. It is unclear how long after the lidocaine injection the participants are put into the driving test, but one would assuming 15-20 minutes at best. Those who had actual surgery under WALANT may report that even if the actual surgical procedure had taken place within 20 minutes or so, the usual banter, checking out, and paperwork would account for another 30 minutes, notwithstanding the time it takes to find where you parked your car in a hospital carpark! Hence, it is possible that by the end of the 55-minute drive, the anaesthetic would have been well worn off if the actual surgery and hospital experience is taken into account.
This is complicated by the fact that there is in fact an absence of a pain generator (ie actual surgery) in the study participants and hence the effect of the anaesthesia wearing off is not overlapped by an increase in pain. It is not uncommon to have BOTH numbness and pain at the same time (as many carpal tunnel syndrome sufferers can attest); hence, the presence of persisting numbness found in all participants after the driving course does not equate to comfort or lack of pain if surgery is actually performed.
Of interest as well is the largely unchanged frequency of right-hand-only driving, considering that a bulky soft dressing was applied to the numbed right arm. The question is whether the dressing presents an obstacle to adequate grip of the steering wheel, although part of the answer may be gleaned from the photos provided in the paper. From what I can tell, I would not call the dressing bulky, although it may be a functionally adequate dressing for certain hand surgery.
As a result of their findings, the authors “recommend that surgeons do not discourage patients from driving immediately after WALANT surgical procedures in the hand”; such enthusiasm may have to be tempered by real-world statutory requirements of local jurisdictions governing driving laws, and insurance clauses covering how impairment is defined. At this point, the authors’ results do not provide a solid foundation of vigorous legal defense of this recommendation.