Peripheral Nerve Repair Using a Nerve Protector and Detensioning Sutures

Currently, several options exist when addressing peripheral nerve repairs. The essential components of an effective repair include minimizing tension while maximizing strength and promoting a healing environment.1 End-to-end repair of nerve ends with or without nerve grafting is the gold standard method of nerve repair. This can be accomplished with sutures, fibrin glue, or a combination of each. Fibrin glue-only techniques are thought to reduce iatrogenic trauma to the repair site due to epineural sutures through the formation of an adhesive capsule that reduces fibrosis at the coaptation site.2 However, when used alone, fibrin glue was shown to have a higher rate of dehiscence.2 Also, many studies have found mixed results when comparing a suture-only repair and a suture repair with fibrin glue.2 The use of nerve conduits and protectors has been growing as more devices gain FDA approval. Connector-assisted repairs (CAR) have been shown to have equal to or better outcomes than direct suture repair for nerve gaps <5 mm.3 The coaptation aid is theorized to offload tension at the repair site using detensioning sutures, minimize irritation at the repair site, allow diffusion of nutrients into the repair site while protecting the repair from surrounding tissues, and permit direct visualization of the repair due to the transparent connector.3 The coaptation aid can be used with or without direct suture repair of the damaged nerve. When comparing direct repair without a conduit to CAR for upper extremity nerve injuries, patients with a CAR reported greater sensory recovery.4 There are, however, no current in vivo studies that compare direct suture repair and suture repair with a nerve protector. This manuscript will describe the use of a nerve protector, fibrin glue, and detensioning sutures to supplement end-to-end epineural repair of a peripheral nerve injury. The use of detensioning sutures on either side of the repair site is hypothesized to aid in reducing dehiscence and ensure the stability of the nerve wrap around the repair. Fibrin glue is used to strengthen the suture repair site while the detensioning sutures span from the nerve protector to the healthy epineurium to reduce strain on the site of neurorrhaphy. To our knowledge, there are no current articles detailing this technique. TECHNIQUE The following procedure steps are to be taken under microscopic guidance after identifying the damaged nerve and determining whether direct repair is appropriate, or the use of allograft or autograft is necessary. A video of the following procedure is available for the reader to view (Supplemental video file 1, Supplemental Digital Content 1, https://links.lww.com/TIO/A88). The nerve ends are sharply debrided to expose healthy nerve ends and reapproximated (Fig. 1A). A standard epineural repair is done with interrupted sutures; the size of the suture as well as the number of stitches is dependent on the size of the nerve and the surgeon’s preference. In this demonstration, an end-to-end repair using four epineural 9-0 nylon sutures was performed (Fig. 1B). Fibrin glue was then applied to the repair site (Fig. 1C). A nerve protector was wrapped around the coaptation site. In this case, it was the Axoguard nerve protector (AxoGen Inc., Alachua, FL), which was prepared by soaking in normal saline for a few seconds before being cut to size. The protector should extend ∼5 mm on each side of the repair site and should be large enough to wrap around the repaired nerve completely. The nerve was then circumferentially enclosed by the nerve protector (Fig. 1D). A detensioning suture was placed using 9-0 nylon on both sides of the nerve repair in a transverse mattress fashion (Fig. 1E–I). Gentle tension can be applied proximal and distal to the nerve repair to ensure the detensioning sutures maintain functionality. The wound was irrigated, hemostasis was ensured, and the wound was closed in layers. Postoperatively, our protocol is to keep the patient non-weight-bearing on the operative extremity with appropriate splinting to protect the repair for 3 weeks.FIGURE 1: Surgical Procedure. A, Nerve ends approximated. B, End-to-end neurorrhaphy. C, Nerve protector placed, fibrin glue added. D, Nerve protector wrapped circumferentially. E and F, Transverse mattress 9-0 nylon suture from one end of the protector to the epineurium. G, Second similar transverse mattress 9-0 nylon suture at the other end. H and I, Final construct.Expected Outcomes To the best of our knowledge, this technique has not been previously described, and no outcomes have been published in the literature. We anticipate similar or superior outcomes to traditional nerve repair techniques. The addition of the detensioning sutures to the nerve protector should increase the stress required for the repair to fail. Complications The complications of this procedure include those typically associated with nerve repair, including bleeding, infection, damage to surrounding structures, neuroma formation, and failure to recover neurological function. Placing the detensioning sutures does slightly increase operative time, but not significantly. Salvage options include excising the diseased nerve and bridging the repair with nerve grafting if a significant gap exists or nerve transposition from a healthy nerve fascicle.