After 2 months of denervation, the number of motor units in the muscle decreases; after 6 months of denervation, muscle atrophy and weakness are irreversible and successful nerve reconstruction does not generally restore function. The babysitter procedure was reported to successfully avoid muscle atrophy. One study found that the babysitter procedure with a 40% neurectomy was most suitable; however, the amount of donor nerve that can be borrowed for the babysitter procedure in peripheral nerve injury is unknown.
One hundred adult female Sprague-Dawley rats were used in this study. The rats were randomly allocated to 5 groups (groups A–E; n = 20 each). The rats underwent different surgeries based on their grouping. At 6, 12, 18, and 24 weeks after surgery, 5 rats in each group were selected for electrophysiology and muscle force tests. These rats were then killed, and the gastrocnemius and tibialis anterior muscles were harvested for weight measurement and cross-sectional muscle measurement.
The results of the effects on the peroneal nerves and tibialis anterior muscles after the babysitter procedure with 40% and 80% neurectomies showed that the functional ability of the recipient nerves was maintained and the muscle was effectively prevented from atrophy, whereas the 20% neurectomy and end-to-side procedures showed relatively poor performance. The results of the effects on the tibial nerve and gastrocnemius muscles after the babysitter procedure with 20% and 40% neurectomies showed that there was little effect on the donor nerve. By contrast, 80% neurectomy strongly and negatively affected the donor nerve.
Our results indicate that the babysitter procedure using a donor nerve with a partial neurectomy of 40% was the best choice for effectively treating peripheral (peroneal) nerve injury in rats.
From the Departments of *Rehabilitation, and †Orthopedics, Zhongshan Hospital, Fudan University, Shanghai, China; and ‡JMS Burn and Reconstruction Center, Jackson, MS.
Received November 21, 2016, and accepted for publication, after revision February 21, 2017.
This study is supported by the National Nature Science Foundation of the People's Republic of China (grant no. 81371376).
Conflicts of interest and sources of funding: none declared.
Reprints: Jian Zhang, MD, PhD, Department of Rehabilitation, Zhongshan Hospital, Fudan University, No. 180 Fenglin Rd, Xuhui District, Shanghai, China. E-mail: email@example.com.