A novel PRP-filled collagen tube reliably clinically restores meaningful sensory and motor function across long nerve gaps with long repair delays and in older patients: a case series

Background Autografts, the clinical "gold standard" technique for restoring meaningful function across peripheral nerve gaps, have limitations, including the need to sacrifice a sensory nerve and being reliably effective only for short gaps (< 4 cm), short repair delays (< 5 months), and young patients (< 25). Further, as the value of any of these three variables increases, recovery decreases, and when the values of two or all three increase simultaneously, recovery is minimal or none. Method Clinically, upper-extremity nerve gaps were bridged with a novel autologous PRP-filled collagen tube to determine whether this induced meaningful sensory and motor function without the limitations on recovery seen by autografts due to increasing gap length, repair delay, and patient age. Results Repairs were performed on nine nerves in eight patients, aged 18–58 years (mean 35.8 years), with gaps 5–12 cm (mean 6.4) long and repair delays of 0.1–3.25 years (mean 0.94). Meaningful motor function was restored to 44% of the nerves, while 67% developed meaningful sensory function, including 100% with sensitivity to 4–8 different types of sensory stimuli, and 78% with fingertip static 2-point discrimination ≤ 15 mm. These recoveries developed despite each patient having the values of 2–3 of the variables that restrict recovery, simultaneously large. Conclusions Without sacrificing a sensory nerve, bridging nerve gaps with a novel PRP within a collagen tube, a technique shown to reliably and rapidly eliminate chronic neuropathic pain in each patient, restores meaningful sensory and motor function despite simultaneously long nerve gaps and long repair delays in older patients, conditions where autografts and other techniques exert little to no effect. Further testing will determine the potential limitations of this technique and whether further modifications to the PRP can induce more extensive recovery.