11 Digital Nerve Repair


11 Digital Nerve Repair

Dariush Nikkhah

11.1 Digital Nerve Repair

Digital nerve injuries are common in hand trauma and the most frequently injured are the peripheral nerves. Best outcomes in terms of sensory recovery are seen in children and young adults with more variable results in adults. The prime goals after epineural repair are to achieve some sensory recovery and to reduce the chances of neuroma formation. Digital nerve repair should ideally be done under a microscope to facilitate accurate epineural repair (Fig. 11‑1, Fig. 11‑2, Fig. 11‑3). In some cases, injury, secondary to machinery such as a powered circular saw, can result in segmental defects that cannot be repaired end to end. This necessitates nerve grafting either from the forearm or dorsal wrist. Other options include vein conduits, although these are only effective in short nerve gaps of 1 cm. If nerve gaps are greater than 1 cm, the vein conduit is likely to collapse, there by impeding nerve regeneration.

Fig. 11.1 Cut ends of radial digital nerve secondary to a knife laceration.
Fig. 11.2 Using a green background, the ends of the divided digital nerve are cut clean in preparation for epineural repair.
Fig. 11.3 Four 8.0 Ethilon stitches were used to repair the nerve. Usually the ends of the first two stitches are kept long so the surgeon can turn the repair around to do the back wall stitches.

11.2 Nerve Grafting for Segmental Defects

The case demonstrated highlights a segmental defect of 1 cm, which cannot be repaired primarily end to end (Fig. 11‑4). Many authors feel that nerve grafting is the gold standard approach for repair in these injuries. Donor site includes the forearm, either the medial or lateral antebrachial nerves of the forearm. These nerves run suprafascially and with the superficial veins (Fig. 11‑5, Fig. 11‑6). The branches of the main nerves should be ideally taken to minimize donor site morbidity. The nerve stumps can also be buried into the muscle to reduce the risk of donor site neuroma. Finally, an end-to-end repair without tension is achieved with the nerve graft (Fig. 11‑7).

Fig. 11.4 Segmental nerve defect between jeweller’s forceps secondary to circular saw.
Fig. 11.5 (a,b) The nerve branches run with the veins above the fascia. The veins should be marked before the elevation of the tourniquet and thin skin flaps raised. The segment of donor nerve is measured for resection.
Fig. 11.6 Bird’s eye view of donor site and recipient site for nerve graft.
Fig. 11.7 The nerve is repaired end to end to the proximal and distal stumps of the recipient site with 8.0 Ethilon.

An alternative site for digital nerve graft harvest is the posterior interosseous nerve (PIN), which is located in the dorsal wrist (Fig. 11‑8).

Fig. 11.8 One can harvest up to 3.5 cm of PIN graft material. This nerve is located under the extensor retinaculum on the radial aspect of the fourth extensor compartment.

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May 21, 2020 | Posted by in Hand surgery | Comments Off on 11 Digital Nerve Repair
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