title: Restoration of ulnar nerve motor function by pronator quadratus motor branch: an anatomical study.
abstract: BACKGROUND
  The traditional surgical approach to repair of brachial plexus lesions involves use of whole segment ulnar nerve graft for contralateral seventh cervical (cC7) nerve root transfer, which sabotages the possibility of ulnar nerve recovery. We assessed the anatomical feasibility of a new approach that involves preservation of the motor branch of ulnar nerve (MBUN), for a later stage repair using the recovered pronator quadratus motor branch (PQMB), subsequent to the cC7 transfer procedure.
  
  
  METHODS
  Twenty-seven adult cadaver arms and one side of fresh adult cadaver were used in this study. The anterior interosseous nerve and its PQMB, as well as the motor and sensory branches of the ulnar nerve were dissected. The distances from the end of PQMB to the mid-point of a line joining the radial styloid and ulnar styloid, as well as to the point of divergence of the ulnar nerve, were measured. The MBUN was dissected from distal to proximal and the maximum length was measured. The diameter and number of axons of the nerve branches were also recorded.
  
  
  RESULTS
  The distance from the end of the PQMB to the midpoint of the radial styloid and ulnar styloid was 6.04 ± 0.52 cm, and that to the point of divergence of the ulnar nerve was 8.02 ± 0.63 cm. The maximum length of the MBUN after its dissociation was 9.70 ± 1.38 cm. The mean diameters of axons of the MBUN and PQMB were 0.09 ± 0.02 cm and 0.05 ± 0.01 cm, respectively. The corresponding mean numbers of axons were 2913 ± 624 and 757 ± 183, respectively.
  
  
  CONCLUSIONS
  The results indicate that the PQMB is suitable for transferring to the MBUN without nerve graft. This anatomical study paves the way for further testing of this new procedure after cC7 transfer in clinical settings.
authors: Department of Hand Surgery, Huashan Hospital, Fudan University, No. 12 Wulumuqizhong Road, Shanghai, 200040, People's Republic of China.|Key Laboratory of Hand Reconstruction, Ministry of Health, Shanghai, 200040, People's Republic of China.
authors: Jing
authors: J
authors: Rui
authors: Department of Hand Surgery, Huashan Hospital, Fudan University, No. 12 Wulumuqizhong Road, Shanghai, 200040, People's Republic of China.
authors: Yingjie
authors: Y
authors: Zhou
authors: Department of Hand Surgery, Huashan Hospital, Fudan University, No. 12 Wulumuqizhong Road, Shanghai, 200040, People's Republic of China.
authors: Le
authors: L
authors: Wang
authors: Key Laboratory of Hand Reconstruction, Ministry of Health, Shanghai, 200040, People's Republic of China.|Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, 200040, People's Republic of China.
authors: Jifeng
authors: J
authors: Li
authors: Department of Hand Surgery, Huashan Hospital, Fudan University, No. 12 Wulumuqizhong Road, Shanghai, 200040, People's Republic of China.|Key Laboratory of Hand Reconstruction, Ministry of Health, Shanghai, 200040, People's Republic of China.
authors: Yudong
authors: Y
authors: Gu
authors: Department of Hand Surgery, Huashan Hospital, Fudan University, No. 12 Wulumuqizhong Road, Shanghai, 200040, People's Republic of China. laojie633@sina.com.|Shanghai Key Laboratory of Peripheral Nerve and Microsurgery, Shanghai, 200040, People's Republic of China. laojie633@sina.com.
authors: Jie
authors: J
authors: Lao
mesh_terms: D001132:Arm / Q000601:surgery; D001917:Brachial Plexus / Q000293:injuries / Q000601:surgery*; D005542:Forearm / Q000294:innervation*; D006801:Humans; D018482:Muscle, Skeletal / Q000294:innervation; D016067:Nerve Transfer / Q000379:methods*; D014459:Ulnar Nerve / Q000601:surgery*
keywords: Anatomical study; Contralateral C7 transfer; Pronator quadratus motor branch; Ulnar nerve