Neuromuscular Pedicle Of The First Dorsal Interosseous Muscle Branch Transfer To Renovate Opponens Policis: Applied Anatomy Study

BACKGROUND & OBJECTIVEThumb function accounts for 36%-40% of hand function, while the function of the thumb opposing function accounts for 60% of motor function. The dysfunction of thumb opposition, which influences the hand function seriously, mainly is caused by peripheral nerve injury and hand injury. As the opposing muscle of thumb plays a major role in the thumb opposition movement, how to repair the function of opposing muscle becomes the focus of clinical treatment and research.The opposition movement which is a complex associated movement with poly-muscle and poly-joint, needs four activities of abduction, pronation, radial leaning and flection. The thumb opposition muscle is the most important muscle, while the first metacarpophalangeal joint is the most important joint. To evaluate the effect of functional rehabilitation of thumb opposition, the main consideration is the angle of thumb abduction and pronation after operation as only sufficient abduction and pronation can accomplish the function of pinch and grip.At present, the methods for functional reconstruction of thumb opposition include three types:fixed reconstruction, tendon transposition and various kinds of microsurgery method. The research of peripheral nerve injury and repair has been great progress at home and abroad, but promoting nerve regeneration, functional reconstruction, variant nerve transplantation, tissue engineering nerve applications and so on, needs further study. Currently, various tendon transpositions to repair the function of thumb opposition are the most methods of clinical applications. However, it has not a standard surgical mode for functional reconstruction of thumb opposition as the complexity of hand trauma and peripheral nerve injury. In recent years, many scholars whose research direction is the transplantation of nerve muscle with pedicle or without, has done a lot of work in the microsurgical reconstruction of thumb opposition research and achieved some results, but surgery is difficult, technique is demanded and long-term effect is uncertain.Fixed reconstruction usually uses bone fusion form. Bone graft fixation of the first and second metacarpal which is mainly applied in bone and joint disease influenced opposition function and is a suitable surgical mode in case of absence of suitable dynamic tendon to switch.With the clinical application of artificial joints and the development of microsurgical techniques, this surgical mode is applied less and less. The most widely used method in clinical application is the tendon transposition reconstruction of thumb opposition, and at present almost all the forearm muscles were used as donor area muscle of functional reconstruction of thumb opposition. The key points of tendon transposition reconstruction of thumb opposition are the choice of tendon transposition, whether to rebuild the pulley and the pulley position, embedded point of transfer tendon. After applying the surgery, radial abduction function of thumb can be most partial restoration, but thumb pronation is not enough to do action of opposition sufficiently. Therefore, the surgical mode which can be more consistent with biomechanical demand and physiological function is still exploring. The research about variant nerve and tissue engineering nerve progress rapidly in recent years and there are few clinical reports at home and abroad, but there is still a long way to reach the large-scale clinical application. With the development and maturation of microsurgery, a variety of microsurgical methods of reconstruction of thumb opposing functions are growing, which mainly include:1. small muscle graft pedicled with neurovascular, such as the little finger abductor translocation for reconstruct thumb opposition function; 2. motor nerve transposition for repair thenar branch, such as third lumbrical branch and anterior interosseous nerve branch of ulnar nerve transposition; 3. small muscle graft with anastomosis vascular nerve, such as the extensor digitorum brevis and pectoralis minor muscle used for repair thumb opposition function. Many scholars believe that this approach can better restore the physiological function of muscle itself and overcome the drawbacks of mechanical and traction methods. However, a higher technique is demanded and long-term clinical effects need further observation.The main problems which exist in current reconstruction of thumb opposition in treatment are:1. mismatch biomechanics of the thumb opposition which is often formed laterad opposition or digital opposition angulation, so that the effects are not satisfied; 2. not enough of shift muscle strength or glide extent which bring the thumb to opposition insufficient or can not meet the functional requirements; 3. injury of significant tendon but some residual dysfunction; 4. reconstruction of tackle or around the ligament carpal transversum or a tendinous insertion, shift tendon to overcome resistance resulting from activities so affecting the flexibility of thumb opposing activities, while long-term friction of tendon in the pulley location which easily wear resulting in tendon adhesion or rupture; 5. less satisfactory appearance. The research about neuromuscular pedicle has been reported from the very early at home and abroad, the technology of neuromuscular pedicle transfer has been applied in the ENT, reshaping and so on, and the relevant basic and clinical research is also conducted. Neuromuscular pedicle is that small motor nerve branches near recipient area together with a small piece of muscle tissue are transferred to plant bed. Severed nerve branches within pedicle rely on denervation bio-induction, which grow into the muscle graft, give out buds and form new motor endplates in order to repair the muscle motor function. Neuromuscular pedicle can retain a certain amount of nerve branches which can be fixed easily, accrete well in plant bed and recovery early and motor endplates. The host site of neuromuscular pedicle transfer is generally small and important function of the muscles, so as to ensure that the nerve buds within pedicle grow into the whole piece of muscle to restore its function, which also consistent with the operation principle that the less important tissue uses to repair more important tissue in the field of microsurgery and coincident with the characteristics of repair of thumb opposing muscle. Clinically, the injury of thumb opposing function mainly dues to the damage of the median nerve branch which is often irreversible. The injury of nerve results in the loss nerve atrophy of thenar muscle. The reinnervation of thenar muscle must be restoration as soon as possible, which plays an important role in the recovery of thumb opposing function without doubt. Profundus nervi ulnaris are muscular branches, which mainly dominates hypothenar muscles, all of the interosseous muscle, third and fourth lumbrical muscles, adductor pollicis muscle and deep head of flexor pollicis brevis muscle. This research presumption is through the microsurgical anatomy, to investigate the distribution of profundus nervi ulnaris in correlated muscles, and to supply anatomical data for reconstruction of thumb opposition function which uses a muscular branch of profundus nervus ulnaris. The research includes the two parts as flollowing:Chapter.1 Neuromuscular pedicle of the first dorsal interosseous muscle branch transfer to renovate opponens pollicis:an applied anatomy studyObjective:To provide anatomical basis for neuromuscular pedicle of the first dorsal interosseous muscle branch with blood supply transposition to renovate opponens pollicis.Methods:Twenty cadaveric upper extremities were dissected. The course, diamaeter, interfascicular dissectible length of the first dorsal interosseous muscle branch were investigated. To simulate using neuromuscular pedicle of the first dorsal interosseous muscle branch with blood supply to renovate the opponens pollicis.Results:The first dorsal interosseous muscle branch of deep branch of ulnar nerve gives off two branches. Each of them enters into the upper or lower 1/3 segment of the muscle. The diameter of the distal branch is (1.5±0.2)mm. The uninjured dissectible length is (2.8±0.3)cm, which is long enough to the recipient area. The diameter of artery which supply the never branch is (0.8±0.3)mm.Conclusions:It is feasible to renovate the opponens pollicis by transferring neuromuscular pedicle of the first dorsal interosseous muscle branch with blood supply. The new neuromuscular pedicle transfer procedure provides an option for restoration of the opponens pollicis function. anatomyChapter.2 The supply and nerves of the first dorsal interosseous muscle:Anatomy studyObjective:To provide anatomical basis for neuromuscular pedicle of the first dorsal interosseous muscle branch with blood supply transposition to renovate opponens pollicis. Study the supply and nerves of it and value the affection of cutting the distal nerve branch of the first dorsal interosseous muscle.Methods:Ten formalin fixed hand were dissected. The form, bood supply, and the nerve were investigated.By using the modified Sihler's neural straining technique to obverse the distribution of the first dorsal interosseous muscle.Results:The most important blood supply of the first dorsal interosseous muscle is the first dorsal metacarpal artery. There are the first palmar metacarpal arteries and the radial artery of index. The nerve of the first dorsal interosseous muscule are from the profundus branch of the unlar nerve. The nerve diverse two branches and each of them enters into the upper or lower 1/3 segment of the muscle.The proximal branch distribute in the upper 2/3 of the muscle, and the distal branch distribute in the lower 1/3.Conclusions:It is feasible to renovate the opponens pollicis by transferring neuromuscular pedicle of the distal branch of nerve of the first dorsal interosseous muscle. The damage of cutting the distal branch of the nerve of the first dorsal interosseous muscle is limited.