The reconstruction of nerve continuity after traumatic nerve injury is the gold standardin hand surgery. Immediate, tension-free, end-to-end nerve suture ensures the bestprognosis. The recovery is mostly promising; however, in a few cases, insufficient outcomes in motor or sensory function are observed. Intra- and extra-fascicular scarring accompanies the nerve regeneration process and limits final outcomes. Secondary nerve release in those cases is recommended. Unfortunately, scarring recurrence cannot be eliminated aftersecondary revision and neurolysis. The supportive influences of mesenchymal stem cells in the process of nerve regeneration were observed in many preclinical studies. However, a limited number of studies in humans have analyzed the clinical usage of mesenchymal stem cells in peripheral nerve reconstruction and revisions. The objective of this study was toevaluate the effects of undifferentiated adipose-derived stromal/stem cell injection during a last-chance surgery (neurolysis, nerve release) on a previously reconstructed nerve.Three patients (one female, two males; mean age 59 ± 4.5 years at the time of injury),who experienced failure of reconstructions of median and ulnar nerves, were includedin this study. During the revision surgery, nerve fascicles were released, and adipose-derived stromal/stem cells were administered through microinjections along the fascicles and around the adjacent tissues after external neurolysis. During 36 months of follow-up, patients noticed gradual signs of sensory and in consequence functional recovery.No adverse effects were observed. Simultaneous nerve release with adipose-derivedstromal/stem cells support is a promising method in patients who need secondary nerverelease after nerve reconstruction. This method can constitute an alternative procedurein patients experiencing recovery failure and allow improvement in cases of limited nerve regeneration. The study protocol was approved by the Institutional Review Board (IRB) at the Centre of Postgraduate Medical Education (No. 62/PB/2016) on September 14, 2016.