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BACKGROUND: The polarity of nerve grafts does not interfere with axon growth. Our goal was to investigate whether axons can regenerate in a retrograde fashion within sensory pathways and then extend into motor pathways, leading to muscle reinnervation. METHODS: Fifty-four rats were randomized into four groups. In Group 1, the ulnar nerve was connected end-to-end to the superficial radial nerve after neurectomy of the radial nerve in the axilla. In Group 2, the ulnar nerve was connected end-to-end to the radial nerve distal to the humerus; the radial nerve then was divided in the axilla. In Group 3, the radial nerve was divided in the axilla, but no nerve reconstruction was performed. In Group 4, the radial nerve was crushed in the axilla. Over 6 months, we behaviorally assessed the recovery of toe spread in the right operated-upon forepaw by lifting the rat by its tail and lowering it onto a flat surface. Six months after surgery, rats underwent reoperation, nerve transfers were tested electrophysiologically, and the posterior interosseous nerve (PIN) was removed for histological evaluation. RESULTS: Rats in the crush group recovered toe spread between 5 and 8 days after surgery. Rats with nerve transfers demonstrated electrophysiological and histological findings of nerve regeneration but no behavioral recovery. CONCLUSIONS: Ulnar nerve axons regrew into the superficial radial nerve and then into the PIN to reinnervate the extensor digitorum communis. We were unable to demonstrate behavioral recovery because rats cannot readapt to cross-nerve transfer.

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Treatment of peripheral nerve injury is not always satisfactory. To improve results, specific adjuvant methods have been used, such as platelet-rich fibrin (PRF) and vein conduits. The goal of this study was to assess whether use of PRF and vein conduits after nerve suture improves nerve regeneration as measured by a functional score and histomorphometry analysis. Ten isogenic spontaneously hypertensive rats were randomly assigned to 4 experimental procedures: 1) Sham group (n = 10); 2) Nerve graft (NG) group (n = 10); 3) Nerve graft covered with a vein conduit (NGVC) (n = 10); and 4) Nerve graft covered with a vein conduit pre-filled with PRF (NGVCP) (n = 10). Nerve repair results were evaluated on: sciatic functional index (SFI) at 0, 30, 60 and 90 days; morphometric and morphologic analysis of the distal nerve; and histological analysis of Fluoro-Gold® stained motor neurons in the anterior horn of the spinal cord. Compared to the Sham control group, the NGVC and NGVCP groups exhibited lower SFI on all measures. The NGVC group showed improvement in SFI at day 90, which was significant compared to the NG group. Fiber and axon diameters were comparable in the NGVC and NGVCP groups, which were both significantly lower than in the Sham and NG groups. Significant improvement was expected with PRF, but in fact the release of factors from this substance was not as effective as hoped.

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We report a case of a bilateral glass injury to the wrist with transection of flexor tendons and the ulnar nerve and artery in a 60-year-old male patient. Two days after his accident, we repaired all divided structures, and on the right hand, we added the transfer of the opponens motor branch to the deep terminal division of the ulnar nerve aimed at first dorsal interosseous and adductor pollicis muscle reinnervation. After surgery, the patient was followed over 24 months. Postoperative dynamometry of the hand, which included grasping, key-pinch, subterminal-key-pinch, pinch-to-zoom, and first dorsal interosseous muscle strength, indicated recovery only in the nerve transfer side.

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Intoduction The pathways of the facial nerve are variable, and knowledge of that is essential. The worst impact caused by facial paralysis is related to quality of life, especially regarding the self-esteem and social acceptance on the part of the patients, leading to social isolation and disruption on their mental health. Case Report A 33-year-old female patient, with a stage-T3 acoustic neurinoma, presented with a moderate dysfunction (grades II to III) according to the House- Brackmann (HB) Facial Nerve Grading System. A 43-year-old male patient, with a stage- T4B trigeminal schwannoma, underwent a resective surgery and presented grade-VI dysfunction according to the HB scale. And a female patient with a stage-T4A acoustic neurinoma presented grade-IV dysfunction according to the HB scale. Discussion We performed a literature review of papers related to surgeries for masseteric-facial nerve anastomosis and compiled the results in table; then, we compared these data with those obtained from our cases. Conclusion The masseteric nerve is the one that shows the best prognosis among all the cranial nerves that could be used, but it is also necessary to perform well the surgical technique to access the facial branch and consequently achieve a better masseteric-facial nerve anastomosis.

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The goal of this systematic review and meta-analysis was to compare nerve conduits and nerve graft for peripheral nerve regeneration. This type of lesion frequently causes disability due to pain, paresthesia and motor deficit. On the PICO process, "P" corresponded to patients with peripheral digital nerve lesions of any age, gender or ethnicity, "I" to interventions with nerve conduits or nerve graft, "C" to the control group with no treatment, placebo or receiving other treatment, and "O" to outcome assessment of nerve regeneration. Initial search found in 3859 studies, including 2001 duplicates. The remaining 1858 studies were selected by title and/or abstract; 1798 articles were excluded, leaving 60 articles for full-text review. Thirty-nine of these 60 reports were excluded as not meeting our inclusion criteria, and 21 articles were ultimately included in the systematic review. For patients older than 40 years, there was a greater mean improvement on S2PD and M2PD tests with grafting, which seemed to be the better surgical technique, positively impacting prognosis. On the M2PD test, there was significantly greater improvement in 11-17.99 mm defects with grafting (P < 0.001); this finding should guide surgical strategy in peripheral nerve regeneration, to ensure better outcomes.

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OBJECTIVE: The common fibular nerve (CFN) is the most frequently injured nerve in the lower limbs. Surgical management is necessary in approximately two thirds of patients and includes neurolysis, suture, graft repair, or nerve transfer. The distal sural nerve is the preferred donor for grafting, but it is not without complications and requires a second incision. We sought to study the surgical anatomy of the lateral sural cutaneous nerve (LSCN) with the aim of repairing CFN injuries through the same incision and as a potential source for grafting in other nerve injuries. METHODS: The popliteal fossa was dissected in 11 lower limbs of embalmed cadavers to study LSCN variations. Four patients with CFN injuries then underwent surgical repair by LSCN grafting using the same surgical approach. RESULTS: At the medial margin of the biceps femoris, the LSCN emerged from the CFN approximately 8.15 cm above the fibular head. The LSCN ran longitudinally to the long axis of the popliteal fossa, with an average of 3.2 cm medial to the fibular head. The mean LSCN length and diameter were 9.61 cm and 3.6 mm, respectively. The LSCN could be harvested in all patients for grafting. The mean graft length was 4.4 cm. Motor function was consistently recovered for foot eversion but was recovered to a lesser extent for dorsiflexion and toe extension. All patients recovered sensitive function (75% of S3). Hypoesthesia was recognized at the calf. CONCLUSIONS: LSCN harvest is a viable alternative for nerve grafting, especially for repairing short CFN injuries, thereby avoiding the need for a second incision.

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BACKGROUND: When it comes to autogenous nerve grafting, the sural and great auricular nerve (GAN) are the 2 nerves predominately used for trigeminal and facial nerve repair. Arising from the second and third cervical ventral rami, the GAN emerges from the posterior border of the sternocleidomastoid coursing superiorly and anteriorly toward the ear. METHODS: Eleven sides from 5 Caucasian and 1 Asian cadaveric heads (all fresh-frozen) were used. One man and 5 women were used with an age at death ranging from 57 to 91 years, with a mean of 80.3 years. Measurements were made from the inferior border of the ear to the GAN, the GAN to the external jugular vein, and the inferior border of the mastoid process to the GAN; the proximal, medial, and distal diameters of the GAN and the length of the GAN that was obtained from this exposure were also measured. RESULTS: The mean distance from the inferior border of the mastoid process to the GAN, inferior border of the ear to the GAN, and GAN to the external jugular vein was 27.71, 31.03, and 13.28 mm, respectively. The mean length of the GAN was 74.86 mm. The mean diameter of its distal, middle, and proximal portions was 1.51, 1.38, and 1.58 mm, respectively. CONCLUSIONS: The GAN is an excellent option for use in nerve grafting for repair of, for example, facial dysfunction. In this study, we review our measurements, techniques for identification, and dissecting techniques for the GAN. The proximity to the operative area and minimal complications associated with GAN grafting might contribute to improved patient satisfaction and better outcomes regarding functional restoration.

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BACKGROUND: The hypoglossal (with or without grafts) and masseter nerves are frequently used as axon donors for facial reinnervation when no proximal stump of the facial nerve is available. We report our experience treating facial nerve palsies via hemihypoglossal-to-facial nerve transfers either with (HFG) or without grafts (HFD), comparing these outcomes against those of masseteric-to-facial nerve transfers (MF). METHOD: A total of 77 patients were analyzed retrospectively, including 51 HFD, 11 HFG, and 15 MF nerve transfer patients. Both the House-Brackmann (HB) scale and our own, newly-designed scale to rate facial reanimation post nerve transfer (quantifying symmetry at rest and when smiling, eye occlusion, and eye and mouth synkinesis when speaking) were used to enumerate the extent of recovery. RESULTS: With both the HB and our own facial reanimation scale, the HFD and MF procedures yielded better outcome scores than HFG, though only the HGD was statistically superior. HGD produced slightly better scores than MF for everything but eye synkinesis, but these differences were generally not statistically significant. Delaying surgery beyond 2 years since injury was associated with appreciably worse outcomes when measured with our own but not the HB scale. The only predictors of outcome were the surgical technique employed and the duration of time between the initial injury and surgery. CONCLUSIONS: HFD appears to produce the most satisfactory facial reanimation results, with MF providing lesser but still satisfactory outcomes. Using interposed grafts while performing hemihypoglossal-to-facial nerve transfers should likely be avoided, whenever possible.

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Treatment of peripheral nerve injuries remains a challenge to modern medicine due to the complexity of the neurobiological nerve regenerating process. There is a greater challenge when the transected nerve ends are not amenable to primary end-to-end tensionless neurorraphy. When facing a segmental nerve defect, great effort has been made to develop an alternative to the autologous nerve graft in order to circumvent morbidity at donor site, such as neuroma formation, scarring and permanent loss of function. Tubolization techniques have been developed to bridge nerve gaps and have been extensively studied in numerous experimental and clinical trials. The use of a conduit intends to act as a vehicle for moderation and modulation of the cellular and molecular ambience for nerve regeneration. Among several conduits, vein tubes were validated for clinical application with improving outcomes over the years. This article aims to address the investigation and treatment of segmental nerve injury and draw the current panorama on the use of vein tubes as an autogenous nerve conduit.