Huawei Liu

Recurrent Pleomorphic Adenoma of the Parotid Gland Intraoperative Facial Nerve Monitoring during Parotidectomy

Objective To determine the benefit to postoperative facial function of intraoperative facial nerve monitoring (IFNM) during recurrent pleomorphic adenoma (RPA) parotid surgery. Study Design Cohort study with planned data collection. Setting Chinese PLA General Hospital. Subjects and Methods Fifty-eight RPA parotidectomies were performed between 2004 and 2012. Recurrence was confirmed by histopathologic examination. None of the patients had preoperative facial palsy. Electromyography-based IFNM was used in 28 patients; 30 patients were unmonitored. The durations of surgery and the severity of postoperative facial nerve palsy were compared between the 2 groups. Results There were no significant differences between the 2 groups in the incidence of immediate or permanent facial paralysis after RPA parotidectomy (P = .95 and P = .36, respectively). However, the differences in the average duration of surgery and the severity of postoperative facial nerve palsy after total parotidectomy or wide resection were significant (P < .01 and P = .01, respectively). In contrast, these differences were not significant after superficial parotidectomies (P = .43 and P = .49, respectively). The average recovery time of temporary facial nerve paralysis was significantly shorter in the monitored group compared with the unmonitored group, independent of surgical technique (P < .01). Conclusion The use of IFNM during total or wide resection RPA parotidectomy reduced the duration of surgery and the incidence of postoperative facial paralysis and enhanced recovery. However, there was little impact on facial nerve outcomes when IFNM was used during superficial RPA parotidectomy.

Clinical and radiological outcomes after treatment of sagittal fracture of mandibular condyle (SFMC) by using occlusal splint in children

This study was designed to investigate the effects of occlusal splints in the treatment of sagittal fractures of the mandibular condyle in children. From January 1995 to December 2011, 37 sagittal fractures of the mandibular condyle in 30 patients aged 4-8 years old were included in this study. All the patients were treated with 1-2mm occlusal splints in the molar region. The mouths of the patients were kept slightly open by the occlusal splints for 3-6 months, and we reviewed the clinical and radiological remodelling of the affected condyles after treatment. Excellent (n=20) and good (n=10) clinical outcomes were achieved with full radiological remodelling seen in 19 and partial remodelling in 11. Treatment with occlusal splints is effective in delivering good results and function with minimal morbidity in children with sagittal fractures of the condyle, while permitting ongoing remodelling and growth in the short term.

Chitosan conduits combined with nerve growth factor microspheres repair facial nerve defects

Microspheres containing nerve growth factor for sustained release were prepared by a compound method, and implanted into chitosan conduits to repair 10-mm defects on the right buccal branches of the facial nerve in rabbits. In addition, chitosan conduits combined with nerve growth factor or normal saline, as well as autologous nerve, were used as controls. At 90 days post-surgery, the muscular atrophy on the right upper lip was more evident in the nerve growth factor and normal sa-line groups than in the nerve growth factor-microspheres and autologous nerve groups. physiological analysis revealed that the nerve conduction velocity and amplitude were significantly higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. Moreover, histological observation illustrated that the di-ameter, number, alignment and myelin sheath thickness of myelinated nerves derived from rabbits were higher in the nerve growth factor-microspheres and autologous nerve groups than in the nerve growth factor and normal saline groups. These findings indicate that chitosan nerve conduits bined with microspheres for sustained release of nerve growth factor can significantly improve facial nerve defect repair in rabbits.

Reconstruction of Beagle Hemi-Mandibular Defects with Allogenic Mandibular Scaffolds and Autologous Mesenchymal Stem Cells

Objective Massive bone allografts are frequently used in orthopedic reconstructive surgery, but carry a high failure rate of approximately 25%. We tested whether treatment of graft with mesenchymal stem cells (MSCs) can increase the integration of massive allografts (hemi-mandible) in a large animal model. Methods Thirty beagle dogs received surgical left-sided hemi-mandibular defects, and then divided into two equal groups. Bony defects of the control group were reconstructed using allografts only. Those of the experimental group were reconstructed using allogenic mandibular scaffold-loaded autologous MSCs. Beagles from each group were killed at4 (n = 4), 12 (n = 4), 24 (n = 4) or 48 weeks (n = 3) postoperatively. CT and micro-CT scans, histological analyses and the bone mineral density (BMD) of transplants were used to evaluate defect reconstruction outcomes. Results Gross and CT examinations showed that the autologous bone grafts had healed in both groups. At 48 weeks, the allogenic mandibular scaffolds of the experimental group had been completely replaced by new bone, which has a smaller surface area to that of the original allogenic scaffold, whereas the scaffold in control dogs remained the same size as the original allogenic scaffold throughout. At 12 weeks, the BMD of the experimental group was significantly higher than the control group (p<0.05), and all micro-architectural parameters were significantly different between groups (p<0.05). Histological analyses showed almost all transplanted allogeneic bone was replaced by new bone, principally fibrous ossification, in the experimental group, which differed from the control group where little new bone formed. Conclusions Our study demonstrated the feasibility of MSC-loaded allogenic mandibular scaffolds for the reconstruction of hemi-mandibular defects. Further studies are needed to test whether these results can be surpassed by the use of allogenic mandibular scaffolds loaded with a combination of MSCs and osteoinductive growth factors.

Chitosan conduit combined with hyaluronic acid prevent sciatic nerve scar in a rat model of peripheral nerve crush injury

In the present study, the effects of hyaluronic acid (HA) combined with chitosan conduit on peripheral nerve scarring and regeneration were investigated in a rat model of peripheral nerve crush injury. A total of 60 Sprague-Dawley rats were randomly distributed into four groups (15 rats in each group), in which the nerve was either not treated (control group) or treated with chitosan conduit, hyaluronic acid, or chitosan conduit coupled with hyaluronic acid following clamp injury to the sciatic nerve. The surgical sites were evaluated by assessing the sciatic functional index, the degree of scar adhesions, the numbers of myelinated nerve fibers, the average diameter of myelinated nerve fibers and the myelin sheath thickness. Larger epineurial scar thickness was observed in the control groups compared with the treatment groups at 4, 8 and 12 weeks following surgery. There was no significant difference in scar adhesion among the four groups at 4 weeks following surgery. However, animals receiving chitosan coupled with HA demonstrated better neural recovery, as measured by reduced nerve adherence to surrounding tissues, less scar adhesion, increased number of axons, nerve fiber diameter and myelin thickness. In conclusion, the application of chitosan conduit combined with HA, to a certain extent, inhibited sciatic nerve extraneural scaring and adhesion, and promoted neural regeneration and recovery.

A comparative study of acellular nerve xenografts and allografts in repairing rat facial nerve defects

Acellular nerves are composed of a basal lamina tube, which retains sufficient bioactivity to promote axon regeneration, thereby repairing peripheral nerve gaps. However, the clinical application of acellular allografts has been restricted due to its limited availability. To investigate whether xenografts, a substitute to allograft acellular nerves in abundant supply, could efficiently promote nerve regeneration, rabbit and rat acellular nerve grafts were used to reconstruct 1 cm defects in Wistar rat facial nerves. Autologous peroneal nerve grafts served as a positive control group. A total of 12 weeks following the surgical procedure, the axon number, myelinated axon number, myelin sheath thickness, and nerve conduction velocity of the rabbit and rat‑derived acellular nerve grafts were similar, whereas the fiber diameter of the rabbit‑derived acellular xenografts decreased, as compared with those of rat‑derived acellular allografts. Autografts exerted superior effects on nerve regeneration; however, no significant difference was observed between the axon number in the autograft group, as compared with the two acellular groups. These results suggested that autografts perform better than acellular nerve grafts, and chemically extracted acellular allografts and xenografts have similar effects on the regeneration of short facial nerve defects.

Phase II Study of Post-surgery Radiotherapy Combined with Recombinant Adeno-viral Human P53 Gene Therapy in Treatment of Oral Cancer

Objective: To evaluate benefits of Recombinant Adeno-viral Human p53 (rAd-p53) gene therapy combined with radiotherapy in prevention of oral cancer recurrence after a radical resection. Methods: A total of 215 patients with resectable Tongue Cancer (TCa) and 268 patients with resectable Gingival Carcinoma (GCa) satisfying the inclusion criteria and were randomly assigned to two groups: the Experiment Group (EG) and the Control Group (CG). The EG received multi-point injections of rAd-p53 into the wound surface at a dose of 1 × 10 12 Viral Particles (VP) after a radical resection. Both EG and CG were given radiotherapy at a total dose of 60 Gy three weeks after surgery. All these patients will be followed at least for 3 years. Results: Among these 483 cases, 107 patients (57 in EG and 50 in CG) finished 3-years follow-up. Two cases (2/27) of TCa and 2 (2/30) in GCa patients had a local recurrence in EG, but 8 (8/24) TCa and 8 (8/26) GCa patients in CG had a local recurrence. Both recurrent rates of TCa (33.3%) and GCa (30.8%) in CG are statistically significantly higher than that of TCa (7.4%) and GCa (6.7%) in EG, respectively. The overall recurrent rate in EG is 7.0%, which is also statistically significantly lower than that (32%) in CG. Overall 3-years survival (OS) rate of EG is 100% and the progress free survival (PFS) rate is 93.0% and the minimum PFS time is 29 months. The 3-years OS and PFS rates of CG are 94.0% and 68.0%, respectively. Except for self-limited fever, no other adverse reaction was found to be relative to rAd-p53.

PI3K/Akt and ERK/MAPK Signaling Promote Different Aspects of Neuron Survival and Axonal Regrowth Following Rat Facial Nerve Axotomy

The ERK/MAPK and PI3K/Akt signaling pathways play important role in neuronal survival and axonal regeneration after peripheral nerve injury. However, the relative importance and degree of functional overlap of the two pathways are still debated due to lack of in-vivo data. We used rats which underwent a facial nerve axotomy, and examined subsequent ERK/MAPK and PI3K/Akt signaling activity by quantifying phosphorylation of ERK and Akt. We also assessed the survival rate of facial neurons, number of regenerated axons, and the length of axonal regrowth in axotomized animals treated with an inhibitor of ERK/MAPK (U0126) or PI3K/Akt (LY294002) phosphorylation, or with vehicle. Axotomy increased phosphorylation of ERK and Akt in the facial nucleus 7 days after injury. The inhibition of ERK phosphorylation significantly reduced the length of regenerated axons, but not the other parameters. Inhibition of Akt phosphorylation significantly reduced the survival rate of facial neurons and the number of new axons, as well as the length of regenerated axons. The results indicate that facial nerve injury activates the ERK/MAPK and PI3K/Akt signaling pathways in the facial nerve nucleus and its axons. However, the pathways promoted aspects of regeneration with only slight overlap: PI3K/Akt signaling improved the survival of neurons, as well as axonal growth and branching, whereas ERK/MAPK signaling promoted only axonal extension.

Acute Response of Neurons: An Early Event of Neuronal Cell Death After Facial Nerve Injury

OBJECTIVE To research the early acute response events of facial nerve injury. METHODS Sixty male Sprague-Dawley rats were randomly divided into 2 groups. Facial nerve anastomosis was performed for rats in study group. Rats in control group underwent the same surgical procedure, but without cutting off the facial nerve. Before nerve anastomosis and at days 1, 3, 7, 14, and 28 after nerve anastomosis, 5 rats of each group were selected and right side brainstem tissue samples containing the facial nerve nucleus were obtained. Hematoxylin and eosin (H&E) staining and TUNEL detection was performed to observe facial neurons changes. Facial neurons mortality and apoptosis were studied. Expression of caspase-3, LC3, and Beclin1 was detected with Western blot assay. RESULTS In study group on day 7 day after nerve anastomosis, Nissl body dissolution and apoptotic facial neurons were significantly increased, the typical polygonal shape and swollen cells disappeared, the number of facial neurons was significantly lower, and the number of apoptotic facial neurons was significantly higher (P < 0.01). In addition, facial neuron mortality rate was significantly increased at day 7, reaching the peak at day 14. Expression of caspase-3, LC3, and Beclin1 was also significantly up-regulated after nerve anastomosis. CONCLUSION Nissl body dissolution, typical polygonal shape disappearing, cell swelling, facial neuron mortality and apoptosis, and up-regulated expression of caspase-3, LC3, and Beclin1 are the early events of cell death after facial nerve injury, which are the important precursors to facial nerve injury.

Effect of chitosan combined with hyaluronate on promoting the recovery of postoperative facial nerve regeneration and function in rabbits

To determine better solutions for postoperative nerve functional recovery, the effects of chitosan and hyaluronate on perineural scar formation and neural function recovery were investigated in 40 rabbits. Rabbits were randomized into 4 groups: A (chitosan), B (chitosan + hyaluronate), C (hyaluronate) and D (control). The rabbits underwent the same parotidectomy surgery, but different materials were used to cover the operated nerves. By evaluating specific indicators, including vibrissae motion tests, neural electrophysiological examinations and extraneural examinations, it was revealed that the amplitude of vibrissae motion of all groups had increased 6 weeks after surgery. The recovery of Group B was superior compared with all other groups at 4 and 12 weeks post-surgery; however no significant differences were detected. Group B exhibited a great number of nerve fibers, thicker myelin sheath and greater nerve conduction velocity. In summary, the use of a chitosan conduit combined with sodium hyaluronate gel may prevent perineural scar formation in facial nerves and promote nerve functional recovery.