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A combined sensory and motor transfer for median nerve lesions
A COMBINED
S E N S O R Y A N D M O T O R T R A N S F E R FOR M E D I A N N E R V E LESIONS
By J. T. HUESTON,M.S., F.R.C.S., F.R.A.C.S.
Royal Melbourne Hospital, Victoria, Australia A PATIENT with a low median nerve lesion has the combined disability of sensory loss over the radial digital tripod of ~he thumb, index and middle fingers, together with motor loss preventing precision manipulations with this important digital tripod. Unless a high quality of discriminative sensation is restored by median nerve repair, the hand function is grossly impaired and it is unlikely that thenar muscle motor recovery will be adequate in a patient with poor sensory recovery. Hence those patients who require sensory restoration by transfer of a neurovascular island flap often also need restoration of thenar motor balance. Rather than stage these two aspects of reconstruction, it has been found safe and practical to transfer, at the same operation, both sensory and motor elements from the ring finger to the thumb. Having taken a hemidigital neurovascular flap (Hueston, I965) from the ulnarsupplied aspect of the ring finger (Fig. I, A), the lateral aspect of the fibrous flexor sheath of the finger is exposed in its proximal segment beneath the intact lateral skin flap and the flexor digitorum sublimis tendon is removed (Fig. I, t3) and split to allow its withdrawal through a wrist incision. By a Riordan loop at the flexor carpi ulnaris insertion, the sublimis tendon is directed across the thenar eminence in the line of the non-functioning abductor pollicis brevis and brought out beneath the lateral margin of the large excisional defect prepared on the thumb for the island flap (Fig. r, c). The tendon is inserted into the extensor expansion just distal to the metacarpophalangeal joint of the thumb, so that this junction lies beyond the lateral suture line of the island flap (Fig. r, m). A large Wolfe graft is used to resurface the donor site on the ring finger with appropriate darts at each flexure crease. The wounds are closed, dressed and the hand immobilised in plaster before the tourniquet is released. SUMMARY Rather than stage the transfer of the two principal deficiencies in the thumb following the median nerve lesion, namely loss of discriminative sensation and loss of opposition, it is shown that both can be transferred at one operation. A large island flap and sublimis transfer are both taken from the ring finger and transferred by the usual methods to the thumb. REFERENCE
HUESTON,J. T. (1965). Br. J. plast. Surg., I8, 304.
385
386
BRITISH
JOURNAL OF PLASTIC SURGERY
FIG.
I
A~ Planned incisions for dissection of hemidigital island flap transfer from ring finger to thumb. B, T h e island flap and its pedicle are dissected free. T h e sublimis tendon is being detached from the proximal segment of the ring finger, the sheath being entered beneath the intact remaining lateral skin flap. C, T h e tendon re-routed through the sling at flexor carpi ulnaris insertion is lying in the direction of transfer and the island flap lies loosely in its new bed before suture. D, After completion of the combined sensory and motor transfer the wounds are closed using a Wolfe graft in the ring finger defect.
S E N S O R Y A N D M O T O R T R A N S F E R FOR M E D I A N N E R V E LESIONS
By J. T. HUESTON,M.S., F.R.C.S., F.R.A.C.S.
Royal Melbourne Hospital, Victoria, Australia A PATIENT with a low median nerve lesion has the combined disability of sensory loss over the radial digital tripod of ~he thumb, index and middle fingers, together with motor loss preventing precision manipulations with this important digital tripod. Unless a high quality of discriminative sensation is restored by median nerve repair, the hand function is grossly impaired and it is unlikely that thenar muscle motor recovery will be adequate in a patient with poor sensory recovery. Hence those patients who require sensory restoration by transfer of a neurovascular island flap often also need restoration of thenar motor balance. Rather than stage these two aspects of reconstruction, it has been found safe and practical to transfer, at the same operation, both sensory and motor elements from the ring finger to the thumb. Having taken a hemidigital neurovascular flap (Hueston, I965) from the ulnarsupplied aspect of the ring finger (Fig. I, A), the lateral aspect of the fibrous flexor sheath of the finger is exposed in its proximal segment beneath the intact lateral skin flap and the flexor digitorum sublimis tendon is removed (Fig. I, t3) and split to allow its withdrawal through a wrist incision. By a Riordan loop at the flexor carpi ulnaris insertion, the sublimis tendon is directed across the thenar eminence in the line of the non-functioning abductor pollicis brevis and brought out beneath the lateral margin of the large excisional defect prepared on the thumb for the island flap (Fig. r, c). The tendon is inserted into the extensor expansion just distal to the metacarpophalangeal joint of the thumb, so that this junction lies beyond the lateral suture line of the island flap (Fig. r, m). A large Wolfe graft is used to resurface the donor site on the ring finger with appropriate darts at each flexure crease. The wounds are closed, dressed and the hand immobilised in plaster before the tourniquet is released. SUMMARY Rather than stage the transfer of the two principal deficiencies in the thumb following the median nerve lesion, namely loss of discriminative sensation and loss of opposition, it is shown that both can be transferred at one operation. A large island flap and sublimis transfer are both taken from the ring finger and transferred by the usual methods to the thumb. REFERENCE
HUESTON,J. T. (1965). Br. J. plast. Surg., I8, 304.
385
386
BRITISH
JOURNAL OF PLASTIC SURGERY
FIG.
I
A~ Planned incisions for dissection of hemidigital island flap transfer from ring finger to thumb. B, T h e island flap and its pedicle are dissected free. T h e sublimis tendon is being detached from the proximal segment of the ring finger, the sheath being entered beneath the intact remaining lateral skin flap. C, T h e tendon re-routed through the sling at flexor carpi ulnaris insertion is lying in the direction of transfer and the island flap lies loosely in its new bed before suture. D, After completion of the combined sensory and motor transfer the wounds are closed using a Wolfe graft in the ring finger defect.