Raquel Salomone

Mesenchymal bone marrow stem cells within polyglycolic acid tube observed in vivo after six weeks enhance facial nerve regeneration

Autografting is the gold-standard method for facial nerve repair with tissue loss. Its association with high-quality scaffolds and cell implants has disclosed distinct experimental outcomes. The aim of this study was to evaluate the functional and histological effects of bone marrow stem cells (BMSC) combined with polyglycolic acid tube (PGAt) in autografted rat facial nerves. After neurotmesis of the mandibular branch of the rat facial nerve, surgical repair consisted of nerve autografting (groups A-E) contained in pGAT (groups B-E), filled with basement membrane matrix (groups C-E) with undifferentiated BMSC (group D) or Schwann-like cells that had differentiated from BMSC (group E). Axon morphometrics and an objective compound muscle action potentials (CMAP) analysis were conducted. Immunofluorescence assays were carried out with Schwann cell marker S100 and anti-β-galactosidase to label exogenous cells. Six weeks after surgery, animals from either cell-containing group had mean CMAP amplitudes significantly higher than control groups. Differently from other groups, facial nerves with Schwann-like cell implants had mean axonal densities within reference values. This same group had the highest mean axonal diameter in distal segments. We observed expression of the reporter gene lacZ in nerve cells in the graft and distally from it in groups D and E. Group-E cells had lacZ coexpressed with S100. In conclusion, regeneration of the facial nerve was improved by BMSC within PGAt in rats, yet Schwann-like cells were associated with superior effects. Accordingly, groups D and E had BMSC integrated in neural tissue with maintenance of former cell phenotype for six weeks.

Bone marrow stem cells in facial nerve regeneration from isolated stumps

Severe lesions in the facial nerve may have extensive axonal loss and leave isolated stumps that impose technical difficulties for nerve grafting. Methods: We evaluated bone marrow stem cells (BMSC) in a silicone conduit for rat facial nerve regeneration from isolated stumps. Group A utilized empty silicone tubes; in groups B–D, the tube was filled with acellular gel; and, in groups C and D, undifferentiated BMSC (uBMSC) or Schwann‐like cells differentiated from BMSC (dBMSC) were added, respectively. Compound muscle action potentials (CMAPs) were measured, and histology was evaluated. Results: Groups C and D had the highest CMAP amplitudes. Group C had shorter CMAP durations than groups A, B, and D. Distal axonal number and density were increased in group C compared with groups A and B. Conclusions: Regeneration of the facial nerve was improved by both uBMSC and dBMSC in rats, yet uBMSC was associated with superior functional results. Muscle Nerve 48: 423–429, 2013

Assessment of a Neurophysiological Model of the Mandibular Branch of the Facial Nerve in Rats by Electromyography

Objectives: Our objective was to develop an experimental model for the noninvasive and objective evaluation of facial nerve regeneration in rats using a motor nerve conduction test (electromyography). Methods: Twenty-two rats were submitted to neurophysiological evaluation using motor nerve conduction of the mandibular branch of the facial nerve to obtain the compound muscle action potentials (CMAPs). To record the CMAPs, we used two needle electrodes that were inserted into the lower lip muscle of the rat. A supramaximal electrical stimulus was applied, and the values of CMAP latency, amplitude, length, area, and stimulus intensity obtained from each side were compared by use of the Wilcoxon test. Results: There was no significant difference (all p > 0.05) in latency, amplitude, duration, area, or intensity of stimuli between the two sides. The amplitudes ranged between 1.61 and 8.30 mV, the latencies between 1.03 and 1.97 ms, and the stimulus intensities between 1.50 and 2.90 mA. Conclusions: This is a noninvasive, easy, and highly reproducible method that contributes to an improvement of the techniques previously described and may contribute to future studies of the degeneration and regeneration of the facial nerve.

Treatment and Prognosis of Facial Palsy on Ramsay Hunt Syndrome: Results Based on a Review of the Literature

Introductionu2003Ramsay Hunt syndrome is the second most common cause of facial palsy. Early and correct treatment should be performed to avoid complications, such as permanent facial nerve dysfunction. Objectiveu2003The objective of this study is to review the prognosis of the facial palsy on Ramsay Hunt syndrome, considering the different treatments proposed in the literature. Data Synthesisu2003We read the abstract of 78 studies; we selected 31 studies and read them in full. We selected 19 studies for appraisal. Among the 882 selected patients, 621 (70.4%) achieved a House-Brackmann score of I or II; 68% of the patients treated only with steroids achieved HB I or II, versus 70.5% when treated with steroids plus antiviral agents. Among patients with complete facial palsy (grades V or VI), 51.4% recovered to grades I or II. The rate of complete recovery varied considering the steroid associated with acyclovir: 81.3% for methylprednisolone, 69.2% for prednisone; 61.4% for prednisolone; and 76.3% for hydrocortisone. Conclusionsu2003Patients with Ramsay-hunt syndrome, when early diagnosed and treated, achieve high rates of complete recovery. The association of steroids and acyclovir is better than steroids used in monotherapy.

Quantitative histological analysis of the mandibular branch of the facial nerve in rats

PURPOSEnTo establish a model to quantitative histological analysis of the mandibular branch of the facial nerve in rats.nnnMETHODSnEleven Wistar rats had their right and left mandibular branches of the facial nerve surgically removed and were sacrificed afterwards. Quantitative histological analysis was performed with: a) partial number of axons; b) partial area of the transversal cut of the nerve (9000 μm(2)); c) partial density. The averages of partial density were obtained. The statistical study was established by Wilcoxon test (p=0.05).nnnRESULTSnIn relation to density of axons, comparison between sides shows no statistically significant difference (p=0.248; p=0.533). Mean partial density of distal and proximal samples was, respectively, 0.18 ± 0.02 and 0.19 ± 0.02 axons/μm(2). Comparison between proximal and distal samples shows no statistically significant difference (p=0.859; p=0.182).nnnCONCLUSIONnThis study has successfully established a model to histological quantitative analysis of the mandibular branch of the facial nerve in rats.

Partial lesions of the intratemporal segment of the facial nerve: graft versus partial reconstruction.

Objectives: In cases of partial lesions of the intratemporal segment of the facial nerve, should the surgeon perform an intraoperative partial reconstruction, or partially remove the injured segment and place a graft? We present results from partial lesion reconstruction on the intratemporal segment of the facial nerve. Methods: A retrospective study on 42 patients who presented partial lesions on the intratemporal segment of the facial nerve was performed between 1988 and 2005. The patients were divided into 3 groups based on the procedure used: Interposition of the partial graft on the injured area of the nerve (group 1; 12 patients); keeping the preserved part and performing tubulization (group 2; 8 patients); and dividing the parts of the injured nerve (proximal and distal) and placing a total graft of the sural nerve (group 3; 22 patients). Results: Fracture of the temporal bone was the most frequent cause of the lesion in all groups, followed by iatrogenic causes (p < 0.005). Those who obtained results lower than or equal to III on the House-Brackmann scale were 1 (8.3%) of the patients in group 1, none (0.0%) of the patients in group 2, and 15 (68.2%) of the patients in group 3 (p < 0.001). Conclusions: The best surgical technique for therapy of a partial lesion of the facial nerve is still questionable. Among these 42 patients, the best results were those from the total graft of the facial nerve.

Tibial and fibular nerves evaluation using intraoperative electromyography in rats.

PURPOSEnTo evaluate a new model of intraoperative electromyographic (EMG) assessment of the tibial and fibular nerves, and its respectives motor units in rats.nnnMETHODSnEight Wistar rats underwent intraoperative EMG on both hind limbs at two different moments: week 0 and week 12. Supramaximal electrical stimulation applied on sciatic nerve, and compound muscle action potential recorded on the gastrocnemius muscle (GM) and the extensor digitorum longus muscle (EDLM) through electrodes at specifics points. Motor function assessment was performaced through Walking Track Test.nnnRESULTSnExposing the muscles and nerves for examination did not alter tibial (p=0.918) or fibular (p=0.877) function between the evaluation moments. Electromyography of the GM, innervated by the tibial nerve, revealed similar amplitude (p=0.069) and latency (p=0.256) at week 0 and at 12 weeks, creating a standard of normality. Meanwhile, electromyography of the EDLM, innervated by the fibular nerve, showed significant differences between the amplitudes (p=0.003) and latencies (p=0.021) at the two different moments of observation.nnnCONCLUSIONnIntraoperative electromyography determined and quantified gastrocnemius muscle motor unit integrity, innervated by tibial nerve. Although this study was not useful to, objectively, assess extensor digitorum longus muscle motor unit, innervated by fibular nerve.

Avaliação eletromiográfica e ultrassonográfica do músculo masseter em indivíduos com paralisia facial periférica unilateral

INTRODUCTION: Individuals with peripheral Facial Paralysis (FP) show conditions that lead to unilateral mastication, performed by the non-affected side, mainly due to the difficulty of action of the buccinator muscle. OBJECTIVES: characterize the motor control and morphology of the masseter muscle in individuals with unilateral peripheral FP through electromyographic and ultrasonographic evaluation. METHOD: 16 participants, of both sexes, with ages superior to 18 years old. The study group (SG) consisted of 8 individuals whod had idiopathic unilateral peripheral FP for more than 6 months; the control group (CG) consisted of 8 normal individuals. All the subjects were submitted to the masseter muscle evaluation through surface electromyography (sEMG) and ultrasonography (USG) during the following tasks: rest, clenching with cotton roller between the teeth (CT) and clenching with maximum intercuspation (MIC). RESULTS: There was no statistically significant difference in comparisons within and between the groups concerning the hemifacial asymmetry, both for the sEMG and for the USG. Also there were no significant differences in the activation of the masticatory muscles (masseter and temporal) in the sEMG. CONCLUSIONS: Both the motor control and the morphology of the masseter muscles in individuals with unilateral peripheral FP were similar to those of normal individuals. Although literature suggests that the demand of functional adaptations made by FP individuals could exceed the structural and functional tolerance of the temporomandibular joints, the results indicate that the length of analyzed patients FP was not enough to generate anatomical and physiological differences in the masticatory muscles.

Mandibular Branch of the Facial Nerve in Wistar Rats: New Experimental Model to Assess Facial Nerve Regeneration

Introductionu2003The ideal animal model for nerve regeneration studies is the object of controversy, because all models described by the literature have advantages and disadvantages. Objectiveu2003To describe the histologic and functional patterns of the mandibular branch of the facial nerve of Wistar rats to create a new experimental model of facial nerve regeneration. Methodsu2003Forty-two male rats were submitted to a nerve conduction test of the mandibular branch to obtain the compound muscle action potential. Twelve of these rats had the mandibular branch surgically removed and submitted to histologic analysis (number, partial density, and axonal diameter) of the proximal and distal segments. Resultsu2003There was no statistically significant difference in the functional and histologic variables studied. Conclusionu2003These new histologic and functional standards of the mandibular branch of the facial nerve of rats establish an objective, easy, and greatly reproducible model for future facial nerve regeneration studies.

Polyethylene glycol fusion associated with antioxidants: A new promise in the treatment of traumatic facial paralysis

Recent studies in invertebrates have taught us that early cell membrane regeneration is determinant for axonal recovery and survival after trauma. Many authors obtained extraordinary results in neural regeneration using polyethylene glycol fusion protocols, which also involved microsutures and antioxidants.