Targeted muscle reinnervation (TMR) is an evolving surgical technique with increasing utility, first developed to improve myoelectric prosthetic control in patients with upper extremity loss,1 and recently reported to have positive results in prevention and treatment of neuroma pain.2,3 TMR involves transfer of the residual major sensory or mixed motor-sensory nerve ends to nearby motor recipients of muscles that no longer have a critical function after limb loss. O’Shaughnessy et al4 first reported their results of TMR for transhumeral amputees, and the authors’ surgical technique was subsequently modified.5 Currently, the most commonly used technique for transhumeral TMR uses two access incisions.5 Herein, we describe a single incision anterior approach for transhumeral TMR, which is more expeditious and efficient than the traditional two incision technique.
In the preoperative holding area, pinpoint sites of maximal pain elicited via Tinel sign are marked. The procedure is performed under general anesthesia without paralytic medications in the supine position with the residual limb on a hand table or arm board. An anterior incision is made approximately 2 cm medial to the raphe between the short and long heads of biceps brachii. Fascia is incised over the biceps raphe. Identification of the musculocutaneous/lateral antebrachial cutaneous, median, ulnar, and medial antebrachial cutaneous nerves proceeds as previously described.6 A nerve stimulator used on the 2-mA setting can be used to localize the target motor nerves. The median nerve is typically transferred to the musculocutaneous motor nerve branch to the short head of the biceps, whereas the ulnar nerve is typically transferred to the musculocutaneous motor nerve branch to brachialis in long transhumeral residual limbs.
Next, the skin incision is retracted posteriorly to provide access to the posterior brachium. In the proximal arm, near the axilla, the radial nerve is found along the medial intermuscular septum, posterior to the brachial artery. Dissection then proceeds from proximal to distal along the course of the radial nerve to identify a suitable motor branch, typically a branch to the long or lateral head of the triceps.
Donor nerves are cut distally, and recipient nerves are cut proximally, as is typical for nerve transfer surgery. To avoid complete denervation of the biceps, brachialis, and triceps, careful use of a nerve stimulator before nerve transection is critical to ensure some motor nerve branches to these muscles will be preserved following nerve transection and subsequent nerve transfer. We recommend nerve coaptation with two or three 8-0 or 9-0 nylon epineural sutures followed by fibrin glue. Given the size mismatch between the large donors and small recipients, we also perform vascularized regenerative peripheral nerve interface implantation (vRPNI) around the coaptation site in an effort to mitigate axonal escape, wherein a flap of selectively denervated muscle supplied by the prior transected motor nerve adjacent to the coaptation site is elevated using electrocautery and then wrapped around the coaptation site.7
The residual limb is placed into a lightly compressive ace wrap. If a pain catheter delivering continuous local anesthetic is used, it is removed at the first postoperative visit.
A 41-year-old, otherwise healthy, previously right-hand-dominant man sustained a crush injury resulting in right transhumeral amputation 10 months before presentation. He had significant residual limb and phantom limb pain and was unable to wear his prosthesis because of pain. On examination, he had positive Tinel sign overlying the median, ulnar, and radial nerves, respectively.
The point of maximal Tinel was marked in the preoperative area. The patient was brought to the operating room where a single anterior incision was made (see figure, Supplementary Digital Content 1, which displays a single incision anterior approach transhumeral TMR with surgical marking following scar from previous surgery distally, extending toward the axilla proximally along the anteromedial aspect of the brachium, http://links.lww.com/PRSGO/B362). In addition to a large median nerve neuroma (Fig. 1), the median, ulnar, musculocutaneous, medial antebrachial cutaneous, and radial nerves were identified (Figs. 1, 2) (See Video 1 [online], which displays identification of the radial nerve main trunk and the lateral head triceps branch from an anterior approach, with intraoperative nerve stimulation in preparation for transfer) (See Video 2 [online], which displays intraoperative stimulation of biceps and brachialis nerve branches in preparation for transfer). Nerve transfers were performed from radial nerve to lateral head triceps motor branch (Fig. 3), the median nerve to medial biceps motor branch, and ulnar nerve to brachialis motor branch with vRPNI (Fig. 4) [see figure, Supplementary Digital Content 2, which displays an ulnar nerve to biceps branch of musculocutaneous nerve transfer (A) and a median nerve to brachialis branch of musculocutaneous nerve transfer (B), http://links.lww.com/PRSGO/B363] [see figure, Supplementary Digital Content 3, which displays raising local muscle flaps for vRPNI coverage of TMR nerve transfers—the muscle flap held by the forceps on the left (A) will provide vRPNI coverage of the median nerve to brachialis branch of musculocutaneous nerve transfer (B); the muscle flap held by the forceps on the right (D) will provide vRPNI coverage for the ulnar nerve to biceps branch of musculocutaneous nerve transfer (C), http://links.lww.com/PRSGO/B364] [see figure, Supplementary Digital Content 4, which displays inset of local muscle flaps for vRPNI coverage of TMR nerve transfers—the muscle flap on the left (A) provides vRPNI coverage of the median nerve to brachialis branch of musculocutaneous nerve transfer (B); the muscle flap on the right (C) provides vRPNI coverage for the ulnar nerve to biceps branch of musculocutaneous nerve transfer (D), http://links.lww.com/PRSGO/B365].
TMR has had promising early results, not only for myoelectric prosthesis control8 but also for prevention and relief of neuroma pain.6,9,10 Approximately 25%–50% of all amputees develop chronic pain secondary to symptomatic neuromas, oftentimes preventing the consistent use of a prosthesis.2,11 The nerve transfers in TMR provide a distal target for the free sensory nerve ends in the residual limb, preventing symptomatic neuroma formation while also mitigating neuropathic pain.
An anterior incision permits straightforward access to the musculocutaneous, median, and ulnar nerves. A separate posterior incision has traditionally provided access to the radial nerve.6 This provides access to the major nerves of the arm but requires two incisions and either repositioning of the patient from supine to prone or an assistant to support the arm during the entire posterior portion of the procedure. Repositioning and utilization of a second incision can increase surgical time and potential risk of wound complications. Positioning the residual limb across the chest in a supine position to access the posterior brachium can also be problematic in settings where the surgeon may not have adequate assistance to stabilize the extremity. In addition, such positioning may not provide optimal exposure or a stable platform for neurorrhaphy.
The anterior approach allows adequate visualization of the standard nerve transfer for transhumeral TMR traditionally performed from the posterior approach. This was conceived based on the senior author’s experience performing brachial plexus reconstruction; in such cases using a radial to axillary nerve transfer, an anterior-only approach has previously been described as a safe technique which avoids intraoperative patient repositioning.12 In transhumeral TMR, the exposure required for the short head of biceps transfer is quite proximal, which allows for adequate exposure of the radial nerve (along with its long and lateral head triceps branches) proximal to the spiral groove with minimal additional dissection. Furthermore, in cases where the divided radial nerve has retracted proximally, radial nerve exploration through the anterior approach would be preferable to the double-incision technique, as the anterior approach allows for a more proximal identification of the radial nerve than is possible through a posterior incision.
A single incision anterior exposure allows the surgeon to perform the traditionally posteriorly performed nerve transfers not only safely but also with decreased morbidity and surgical time. We feel that this anterior-only technique presents an excellent alternative to the traditional two incision technique for transhumeral TMR and recommend its use for all cases of transhumeral TMR.
1. Kuiken TA, Dumanian GA, Lipschutz RD, et al. The use of targeted muscle reinnervation for improved myoelectric prosthesis control in a bilateral shoulder disarticulation amputee. Prosthet Orthot Int. 2004;28:245–253.
2. Ducic I, Mesbahi AN, Attinger CE, et al. The role of peripheral nerve surgery in the treatment of chronic pain associated with amputation stumps. Plast Reconstr Surg. 2008;121:908–684; 917.discussion 684
3. Eberlin KR, Ducic I. Surgical algorithm for neuroma management: a changing treatment paradigm. Plast Reconstr Surg Glob Open. 2018;6:e1952.
4. O’Shaughnessy KD, Dumanian GA, Lipschutz RD, et al. Targeted reinnervation to improve prosthesis control in transhumeral amputees. A report of three cases. J Bone Joint Surg Am. 2008;90:393–400.
5. Dumanian GA, Ko JH, O’Shaughnessy KD, et al. Targeted reinnervation for transhumeral amputees: current surgical technique and update on results. Plast Reconstr Surg. 2009;124:863–869.
6. Gart MS, Souza JM, Dumanian GA. Targeted muscle reinnervation in the upper extremity amputee: a technical roadmap. J Hand Surg Am. 2015;40:1877–1888.
7. Valerio IL, Schulz SA, Jordan S, et al. TMR combined with vascularized regenerative peripheral nerve interfaces—a technical evolution in technique for the prevention and management of symptomatic neuromas. Plast Reconstr Surg Glob Open. Accepted for publication.
8. Hargrove LJ, Miller LA, Turner K, et al. Myoelectric pattern recognition outperforms direct control for transhumeral amputees with targeted muscle reinnervation: a randomized clinical trial. Sci Rep. 2017;7:13840.
9. Valerio IL, Dumanian GA, Jordan SW, et al. Preemptive treatment of phantom and residual limb pain with targeted muscle reinnervation at the time of major limb amputation. J Am Coll Surg. 2019;228:217–226.
10. Souza JM, Cheesborough JE, Ko JH, et al. Targeted muscle reinnervation: a novel approach to postamputation neuroma pain. Clin Orthop Relat Res. 2014;472:2984–2990.
11. Wright TW, Hagen AD, Wood MB. Prosthetic usage in major upper extremity amputations. J Hand Surg Am. 1995;20:619–622.
12. Bauer AS, Rabinovich RV, Waters PM. The anterior approach for transfer of radial nerve triceps fascicles to the axillary nerve. J Hand Surg Am. 2019;44:345.e1–345.e6.