Tao Xu,1,2,* Bin Wang,1,2,* Yiming Lu,1,3,4 Renjing Qi,1,2 Yu Sun1,2 

1Department of Orthopedics. Northern Jiangsu People’s Hospital, Yangzhou, Jiangsu Province, 225001, People’s Republic of China; 2Northern Jiangsu People’s Hospital Affiliated to Yangzhou University, Yangzhou, Jiangsu Province, 225009, People’s Republic of China; 3Dalian Medical University, Dalian, Liaoning Province, 116000, People’s Republic of China; 4The Yangzhou School of Clinical Medicine of Dalian Medical University, Yangzhou, Jiangsu Province, 225001, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yu Sun, Department of Orthopedics, Northern Jiangsu People’s Hospital, No. 98 Nantong West Road, Yangzhou, Jiangsu, 225001, People’s Republic of China, Tel +86 18051060619, Fax +86 0514 87373012, Email docsunyu@126.com

Introduction: Whether an innervated reverse digital artery island flap is superior remains controversial. To date, no thorough investigation has been undertaken regarding the exact factors underlying this phenomenon. We aim to systematically summarize the innervated reverse digital artery island flap by leveraging our dataset and extract the key contributing factors.
Materials and Methods: A total of 79 patients from June 2016 to September 2019 who underwent innervated reverse digital artery island flap were evaluated retrospectively. Thirty nine underwent sensory nerve reconstruction with similar diameter of cutaneous branches of the proper digital nerve and stump of the proper palmar digital nerve (S-innervated group), while 40 with different diameter (D-innervated group). Sensory function was assessed by static two-point discrimination and the modified sensory evaluation standard of British Medical Research Council. Motor function was assessed by the total activity measurement. Pigmentation of the flap was also evaluated by Taylor hyperpigmentation scale. Seventy who underwent non-innervated reverse digital artery island flap at the same period was considered as the control group.
Results: All 149 flaps survived completely. There was significant difference in age, operation time, time from injury to surgery, s2PD of the flap within 1 year and pigmentation between S-innervated group and Non-innervated group, while operation time and s2PD of the flap within 1 year between D-innervated group and Non-innervated group.
Conclusion: The nerve diameter matching was a critical factor in innervated reverse digital artery island flap in the early restoration of sensory function and pigmentation. A significant discrepancy in nerve diameters not only compromised the intended therapeutic outcomes but also increased the incidence of neuroma formation.

Keywords: digital artery flap, innervated flap, sensory function, nerve diameter matching, pigmentation