Quantifying the Impact of C7 Root Harvest on Spontaneous, Patient-Initiated Movement of the Donor Upper Extremity
Whitney E Muhlestein, MD1, Tommy Nai-Jen Chang, MD2, Rachel N. Logue Cook, M.S.1, Kate Wan-Chu Chang, MA, MS3, Johnny Chuieng- Yi Lu, MD2, Kevin C. Chung, MD, MS4, Susan H Brown, PhD1 and David Chwei-Chin Chuang, MD2, 1University of Michigan, Ann Arbor, MI, 2Chang Gung Memorial Hospital, Taoyuan, Taiwan, 3Section of Plastic and Reconstructive Surgery, University of Michigan, Ann Arbor, MI, 4Section of Plastic Surgery, University of Michigan, Ann Arbor, MI
INTRODUCTION
The contralateral C7 (CC7) root is a potential source of axons that can be used for nerve transfer in patients with pan-brachial plexus injury (BPI). Its use remains controversial owing to concern for neurological injury to the healthy donor arm. Utilizing wearable motion-sensor technology, we aimed to quantify donor arm morbidity after C7 root harvest, reporting both the time and magnitude of spontaneous, patient-initiated donor arm movement compared to healthy controls.
MATERIALS AND METHODS
Seventeen patients with pan-BPI who underwent transfer of the entire contralateral C7 root for nerve reconstruction and had at least 2 years of follow-up were compared to 14 healthy controls. Each participant wore an accelerometer on both arms for 7 consecutive days. The vector time (VT), or the amount of time measured in hours per day, and the vector magnitude (VM), or the magnitude with which each arm moved measured as a single vector magnitude per second (termed activity units), were collected. VT and VM were compared between the donor arms of patients who underwent C7 root harvest and the arms of control patients.
RESULTS
At mean 7.7 years after C7 root harvest, there was no difference between donor arms and the arms of healthy controls for VT (5.76 hours ± 0.11 vs 5.45 ± 1.22, p = 0.56) or VM (2242236 ± 753852.8 activity units vs 1919223 ± 579723 activity units, p = 0.20). There was also no difference in donor arm VT or VM amongst the C7 root harvest group regardless of donor arm dominance.
CONCLUSIONS
At 7.7 years after C7 root harvest for nerve transfer for pan-BPI, study participants moved their donor arms the same amount of time and with the same magnitude as healthy controls in the real-world setting. These data support the relative safety of C7 root harvest for the donor extremity.
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