Functional pectoralis minor muscle flap transplantation for reconstruction of thumb opposition: an anatomic study and clinical applications

Free Functional Muscle Transfer for Thumb Opposition

Traumatic injuries and other conditions resulting in thenar loss and loss of opposition function can cause significant functional limitations. There are limited options available to restore function and bulk to the thenar musculature. A 26-year-old man had an unfortunate accident at work with a machine mixer creating a crush injury to his left hand. This required several debridements due to the tissue injury and resulted in loss of the thenar muscles and ability to oppose the thumb. He recovered well from the initial injury, however, was left with difficulty with grasp and holding objects due to the loss of thenar motion and strength. His function was also affected by the loss of bulk. He successfully underwent a free functional muscle reconstruction with his serratus anterior. This case report is a description of his reconstruction and a review of the literature. The patient had an excellent outcome. He obtained active opposition and improved grip strength, improving his activities of daily living and vocational life. The serratus anterior muscle can successfully be used for thumb opposition reconstruction. This case report demonstrates good outcomes for both motion and bulk restoration.

Functional pectoralis minor myocutaneous flap transplantation for reconstruction of thumb opposition: An anatomic study with clinical applications

OBJECTIVE

To develop a myocutaneous flap for reconstruction of thumb opposition function in patients with loss of the thenar muscles and skin.

METHODS

An anatomic experiment on the dimensions of the pectoralis minor muscle and its neurovascular supply in 10 adult human cadavers was conducted to evaluate the feasibility of microsurgical transplantation using part of the muscle for thumb opposition reconstruction. Based on these results, we performed surgical thenar reconstruction with a pectoralis minor myocutaneous flap in seven patients (34.7 ± 9.8 years of age) from December 2007 to October 2010.

RESULTS

The transferred muscle was reinnervated with the third lumbrical branch of the ulnar nerve. Six to twelve months after the surgery, follow-up assessment showed that all patients had recovered functional opposition of the carpometacarpal joint with survival of the skin and a muscle power of M4 to M5.

CONCLUSION

Our results support the use of this new technique for thenar and opposition reconstruction in patients with severe loss of the thenar muscles and skin and damage to the median nerve and who wish to improve the appearance of the thenar eminence.

Reinnervation of segmented latissimus dorsi muscle with the distal stump of the thoracodorsal nerve: A preliminary experimental study in rats

To date, nerve stumps have been dissected at the proximal side of the donor muscle for reinnervation of the muscle in free neurovascular muscle transfer. Herein, we examined the use of the distal thoracodorsal nerve, dissected from the muscle belly at the distal side of the latissimus dorsi muscle, for the reinnervation of muscle. The rat right latissimus dorsi muscle was employed as the model for our study. Twenty Wistar rats were used in this study. A rectangular muscle segment was dissected with the distal stump of dominant thoracodorsal nerve. After rotation of muscle, the distal nerve stump was sutured to a severed proximal recipient thoracodorsal nerve (n = 5). The degree of reinnervation through the distal nerve stump was compared with control groups that received proximal-to-proximal nerve sutures (n = 5), nerves that were not severed (n = 5), and severed nerves that were not sutured (n = 5) using electrophysiological, histological, and muscular volume assessments. Reinnervation of the distal nerve stump was confirmed by the contraction of the muscle following electrical stimulation and electromyography. Crossing of axons into motor endplates was confirmed by histology. Results of these assays were similar to that of the proximal nerve suture group. The volume of muscle in the distal nerve suture group was not significant different from that of the proximal nerve suture group (P = 0.63). It was demonstrated that the distal stump of the thoracodorsal nerve can be used to innervate segmented latissimus dorsi muscle. This novel procedure for the reinnervation of transplanted muscle deserves further investigations.