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Vascularized Brachial Plexus Allotransplantation—An Experimental Study in Brown Norway and Lewis Rats

Chang, Tommy Nai-Jen, MD1,2; Chen, Kuang-Te, MD3; Gorden, Tessa, PhD4; Daniel, Bassem W., MD2; Hernon, Catherine, MD2; Shafarenko, Mark, MS5; Huang, Yen-Lin, MD6; Lu, Johhny Chuieng-Yi, MD1,2; Chuang, David Chwei-Chin, MD1,2

doi: 10.1097/TP.0000000000002387
Original Basic Science—General

Background Brachial plexus injuries are devastating. Current reconstructive treatments achieve limited partial functionality. Vascularized brachial plexus allotransplantation could offer the best nerve graft fulfilling the like-with-like principle. In this experimental study, we assessed the feasibility of rat brachial plexus allotransplantation and analyzed its functional outcomes.

Methods A free vascularized brachial plexus with a chimeric compound skin paddle flap based on the subclavian vessels was transplanted from a Brown Norway rat to a Lewis rat. This study has 2 parts. Protocol I aimed to develop the vascularized brachial plexus allotransplantation (VBP-allo) model. Four groups are compared: no reconstruction, VBP-allo with and without cyclosporine A immunosuppression, VBP autotransplantation (VBP-auto). Protocol II compared the recovery of the biceps muscle and forearm flexors when using all 5, 2 (C5 + C6) or 1 (isolated C6) spinal nerve as the donor nerves. The assessment was performed on week 16 and included muscle weight, functionality (grooming tests, muscle strength), electrophysiology and histomorphology of the targeted muscles.

Results Protocol I showed, the VBP-allo with cyclosporine A immunosuppression was electrophysiologically and functionally comparable to VBP-auto and significantly superior to negative controls and absent immunosuppression. In protocol II, all groups had a comparable functional recovery in the biceps muscle. Only with 5 donor nerves did the forearm show good results compared with only 1 or 2 donor nerves.

Conclusions This study demonstrated a useful vascularized complete brachial plexus allotransplantation rodent model with successful forelimb function restoration under immunosuppression. Only the allotransplantation including all 5 roots as donor nerves achieved a forearm recovery.

1 Center for Vascularized Composite Allotransplantation, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, and School of Medicine, Chang Gung University, Taoyuan, Taiwan.

2 Division of Reconstructive Microsurgery, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, Taoyuan, Taiwan.

3 Department of Plastic and Reconstructive Surgery, Saint Paul’s Hospital, Taoyuan, Taiwan.

4 Division of Plastic and Reconstructive Surgery, Department of Surgery, The Hospital for Sick Children and The Hospital for Sick Children Research Institute, Program in Neuroscience and Mental Health, Toronto, Ontario, Canada.

5 Faculty of Medicine, Toronto, University of Toronto, Ontario, Canada.

6 Department of Anatomic Pathology, Chang Gung Memorial Hospital, and School of Medicine, Chang Gung University, Taoyuan, Taiwan.

Received 9 February 2018. Revision received 19 June 2018.

Accepted 20 June 2018.

This study was supported by a grant from the Ministry of Science and Technology Taiwan (NSC94-2314-B-182A-176) and the Chang Gung Memorial Hospital, Linkou, Taiwan (CMRPG3A0441-3).

The authors declare no conflict of interest.

Correspondence: David Chwei-Chin Chuang, MD, Department of Plastic and Reconstructive Surgery, Chang Gung Memorial Hospital, No. 5 Fu-Shing St., Taoyuan, Taiwan. (dccchuang@gmail.com).

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