Expanding the top rungs of the extremity reconstructive ladder: targeted muscle reinnervation, osseointegration, and vascularized composite allotransplantation

Abstract

Osseointegration (OI), targeted muscle reinnervation (TMR), and vascularized composite allotransplantation (VCA) are just a few ways by which our reconstructive ladder is evolving. It is important to recognize that amputation does not necessarily denote failure, but surgeons should strive to find ways to provide these patients with means for obtaining better satisfaction and quality of life postoperatively. TMR and OI have added options for mutilating lower extremity injuries that necessitate amputation. More recently, the senior author (Levin LS) described the "penthouse" floor of the reconstructive ladder being VCA. Despite the advances in VCA over the last 20 years, there are many challenges that face this discipline including indications for patient selection, minimizing immunosuppressive regimens, standardizing outcome measures, establishing reliable protocols for monitoring, and diagnosing and managing rejection. Herein, the authors review TMR, OI, and VCA as additional higher rungs of the reconstructive ladder.

Lower extremity amputation: the emerging role of targeted muscle reinnervation (TMR) and regenerative peripheral nerve interface (RPNI)

“…There are several papers with anatomical roadmaps for both upper and lower extremities to identify the major branch points of motor nerves and motor entry points on muscles [41,[55][56][57][58] . Handheld neurostimulators can also be used intraoperatively to identify the locations of these nerves [59] . These neurostimulators, such as those from Checkpoint Surgical (Cleveland, OH), do not result in neuronal fatigue despite repeated stimulation when identifying the nerves.…”

“…The distal motor nerve and the prepared sensory nerve are coapted usually with 6-0, 7-0, or 8-0 nonabsorbable monofilament suture through the epineurium [60] . Others have described methods in which a single 8-0 suture is placed in the center of the recipient nerve to loosely intussuscept the motor branch into the center of the donor nerve, then reinforcing this with several interrupted 6-0 suture on the epineurium to the fascia and epimysium around the target nerve [Figure 2] [59] . The excision of the prior neuroma can be coded as excision of major peripheral neuroma (64784), and TMR can be coded as pedicle nerve transfers (64905).…”

Free flap reconstruction of elbow soft tissue defects: Lessons learned from 15 years of experience

“…For example, pedicled latissimus dorsi flaps are often limited by deficient pedicle length and are often unable to provide sufficient elbow coverage, particularly in cases of olecranon fracture (Heitmann et al, 2004). As such, there has been growing interest in bypassing lower rungs of the reconstructive ladder and proceeding directly to microvascular free flap coverage, as providing more tissue bulk can better support subsequent limb salvage procedures and functionality of the joint as a whole (Azoury et al, 2020; Chui et al, 2012; Jensen & Moran, 2008; Kahramangil et al, 2022; Koteswara Rao Rayidi et al, 2019). The choice of flap can then be tailored to the defect and aid in avoiding donor site morbidities that may interfere with additional orthopedic interventions, such as external fixation (Jensen & Moran, 2008; Kelley & Chung, 2015).…”