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Regeneration of Facial Nerve Defects Using a Silicone Tube Filled With Dental Pulp Cells
Oral Abstract Session 8: NERVE REPAIR/TMJ/OTHER Inferior Alveolar Nerve Injury in Trauma-Induced Mandible Fractures Andrew B.G. Tay, BDS, MDS, FDSRCSEd, FAMS, Dept. of Oral & Maxillofacial Surgery, National Dental Centre, 5 Second Hospital Avenue, 168938, Singapore (Wong WY; Lye KW; Lai JB) Statement: Current literature reports a wide range of incidence of inferior alveolar nerve (IAN) sensory disturbance after mandible fracture (5.7% to 58.5%) with a wider range of incidence of IAN dysfunction after surgical treatment (0.4% to 91.3%). We report preliminary results of this prospective study with the aim of determining the incidence of IAN injury in mandible fractures before and after treatment. Materials and Methods: Patients with mandible fractures referred to the Department of Oral & Maxillofacial Surgery at the National Dental Centre and SingHealth hospitals who consented were enrolled in this study. Each patient underwent a specific set of neurosensory tests, namely direction stroke, 2-point discrimination and pinprick pain, before treatment. Patients with pure dentoalveolar fractures, pathologic mandible fractures, previous mandible fractures or major surgery, or who were unable to undergo neurosensory testing for any reason were excluded. Treatment options including no treatment, closed reduction and fixation (CRF), and open reduction and internal fixation (ORIF) with or without maxillomandibular fixation (MMF) were offered in line with the current standard of care, and undertaken according to the patient’s choice. Patients underwent the neurosensory testing (NST) protocol described by Zuniga and Essick at 1 week, 6 weeks, 3 months, 6 months and 1 year after treatment. Data were collated in a database and analysed. Method of Data Analysis: Descriptive statistics were used to analyse data. Results: From March 2005 to February 2007, a total of 42 patients with 63 mandible fracture sides were enrolled in the study. The majority were male (78.6%). Ethnic groups included Chinese (50.0%), Indians [from the Indian subcontinent] (23.8%), Malays (19.0%) and others (7.1%). The great majority were Singaporean citizens (81.0%). The etiology of mandible fractures was nearly equally shared by falls (33.3%), interpersonal violence (31.0%) and motor vehicle accidents (28.6%), followed by worksite accidents (4.8%) and sports injuries (2.4%). Of 63 mandible fracture sides, slightly more occurred on the left (54%). Fracture sites were follows: symphysis/parasymphysis between canines (25.4%), anterior body from the canine to 5mm of the mental fora40.e1
men (9.5%), posterior body from 5mm anterior of the mental foramen to the angle (23.8%), angle up to the mandibular foramen (23.8%), upper ramus above the mandibular foramen (0%) and the condylar region above the sigmoid notch (17.5%). Thirty fractures (47.6%) occurred in the mandible bearing the IAN. The majority of mandible fractures were treated by ORIF (69.8%), followed by CRF (27.0%) and no treatment (3.2%). Only cases treated with ORIF had neurosensory disturbance (NSD) and abnormal NST results (mild sensory impairment or worse), both preoperatively (40.9% NSD, 18.2% abnormal NST) and postoperatively (63.6% NSD, 40.9% abnormal NST). There were no instances of post-treatment NSD or abnormal NST results in cases treated with CRF or no treatment. Of the 63 mandible fracture sides, 19 (30.2%) had NSD and 8 (12.7%) had abnormal NST results before treatment. At 1 week after treatment, 28 (44.4%) had NSD and 18 (28.6%) had abnormal NST results. Of 22 mandible fractures in the mandible anterior to 5mm from the mental foramen, 18.2% had NSD with no abnormal NST results before treatment; 40.9% had NSD and 18.2% had abnormal NST results after treatment. In comparison, of 30 posterior mandible sides bearing the IAN, 50% had NSD and 26.7% had abnormal NST results before treatment (of these, 87.5% had a fracture gap of 5 mm or more). After treatment, 63.3% had NSD and 46.7% had abnormal NST results; all were cases treated with open reduction and rigid fixation. Further follow-up is still ongoing. Conclusion: Clinically severe mandible fractures were more likely to be treated with rigid fixation and were more likely to have a higher incidence of IAN injury. Fractures of the mandible body, angle and ramus bearing the IAN had a higher risk of subjective NSD associated with a higher incidence of abnormal objective NST results. References Thurmuller P, Dodson TB, Kaban LB. Nerve injuries associated with facial trauma. Natural history, management, and outcomes of repair. Oral Maxillofac Surg Clin North Am 2001: 13: 283-293 Zuniga JR, Essick GK. A contemporary approach to the clinical evaluation of trigeminal nerve injuries. Oral Maxillofac Surg Clin North Am 1992: 4: 353-367 Zuniga JR, Meyer RA, Gregg JM, Miloro M, Davis LF. The accuracy of clinical neurosensory testing for nerve injury diagnosis. J Oral Maxillofac Surg 1998: 56: 2-8
Regeneration of Facial Nerve Defects Using a Silicone Tube Filled With Dental Pulp Cells Ryo Sasaki, DDS, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjyuku-ku, Tokyo, 162-8666, Japan (Uchiyama H; Ogiuchi H) AAOMS • 2007
Oral Abstract Session 8 Statement: Nerve autografting is the most common surgical procedure currently used for repairing facial nerve defects caused by traffic accidents or malignant tumor resections (Kumar et al, 2002). A number of recent studies have shown the effectiveness of tubulation as an alternative therapy to that of nerve autografting for peripheral nerve gaps (Matsumoto et al, 2000). For large peripheral nerve defects, tubulation alone is limited to nerve regeneration. It has been reported that tubulation using brain-derived neural progenitor cells or Schwann cells promotes nerve regeneration (Murakami et al, 2003). However, use of these neural cells from other neural tissues has potentially serious clinical complications along with ethical considerations. Therefore, we focused on the use of dental pulp as a new cell source for such artificial nerves. Dental pulp is derived from the neural crest, included fibroblasts, and Schwann and stem cells. It is assumed that these cells have an important role in peripheral nerve regeneration. Therefore, we investigated whether transplanted dental pulp cells in a facial nerve gap promoted nerve repair. Materials and Methods: Adult Sprague-Dawley (SD) rats were anesthetized by isoflurane using an original nasal mask. A 7-mm defect was prepared in the buccal branch of the facial nerve. Dental pulp cells were isolated from adult SD rat maxillary incisors containing a transgene-expressing green fluorescent protein (GFP). The defect was bridged with a 10-mm silicone tube filled with GFP-positive dental pulp cells (1.0⫻105) embedded in type I collagen gel. Both the proximal and distal stump of the nerve was inserted about 1.0-mm into the tube and connected with 2 sutures of 9-0 nylons under microscopy. Method of Data Analysis: The regenerated nerve was evaluated by immunohistologic study. Results: 14 days after surgery, a GFP-positive regenerated nerve was observed in the silicone tube. The regenerated nerve included Tuj1-positive axons and RECA1positive vessels. These results suggested that transplanted dental pulp cells may differentiate into supportive cells and may support axonal regeneration. Conclusion: When dental pulp cells are transplanted into a large peripheral nerve defect, they may contribute to the promotion of axonal regeneration. Dental pulp may be a viable source of easily obtainable cells for potential use in facial nerve regeneration. References K. Matsumoto et al, Peripheral nerve regeneration across an 80-mm gap bridged by a polyglycolic acid (PGA)-collagen tube filled with laminin-coated collagen fiber: a histrogical and electrophysiological evaluation of regenerated nerves, Brain Res, 868, 3 P. Kumar et al, Cross-face nerve graft with free-muscle transfer for reanimation of the paralyzed face: a comparative study of the singlestage and two-stage procedures, Plast Reconstr. Surg, 109, 451-462, 2002 T. Murakami et al, Transplanted neuronal progenitor cells in a peripheral nerve gap promote nerve repair, Brain Res, 974, 17-24, 2003
AAOMS • 2007
Effect of Recombinant Human BDNF Gene Therapy on the Nerve Regeneration in Rat Sciatic Nerve Transection Kang-Mi Pang, Korea (Lee JH; Jeon SH; Pang KM; Myoung H; Hwang SJ; Seo BM; Choi JY; Choung PH; Kim MJ) Statement: In cases of transection injury to the peripheral nerve, end-to-end anastomosis of the transected nerve segments is the traditional and widely used method. However, full functional recovery is seldom obtained, and regeneration takes a long time, so many attempts have been made to use neurotrophic factors to improve nerve regeneration. Among them, BDNF (brainderived neurotrophic factor) is known to be associated with survival and regeneration of the central and peripheral nervous systems. The purpose of this study is to verify the hypothesis that recombinant human BDNF-adenovirus injection into transected and repaired rat’s sciatic nerves can enhance nerve regeneration in vivo. Materials and Methods: Recombinant human BDNFadenovirus was obtained from professor Yun-Hee Kim in Kyunghee University and was multiplied and purified in our laboratory. Six-week-old male Sprague-Dawley male rats (n⫽40) were anesthetized i.p. and their left sciatic nerves were exposed and isolated. After transection 5mm distal from the sciatic notch, either 3l of PBS (PBS group, control group) or 3l of recombinant human BDNF-adenovirus (BDNF-Ad group, experimental group) was injected, and one epineural suture with 10-0 nylon was made. The rat’s gait was analyzed at 2, 4, 6, 8 and 10 weeks postoperatively, and their sciatic function index (SFI) was calculated. An electrophysiologic study was completed 5 and 10 weeks postoperatively, and nerve conduction velocity and peak voltage were obtained. After the electrophysiologic study, segments of the sciatic nerves were harvested including the end-to-end anastomosis site. Three longitudinal specimens were used for immunofluoroscent study with NF 200 (neurofilament 200), and the last specimens were prepared for crosssection in each group. Axon density, total axon count and myelin thickness of both proximal and distal stumps were calculated. All data were expressed as mean ⫾ SEM. The statistical significance of the difference between the experimental and control groups at the same interval was analyzed by a Mann-Whitney U test using the StatView II program (version 5.0.01 The SAS Institute, USA). Method of Data Analysis: n/a Results: 1. Gait analysis showed that the BDNF-Ad group’s SFIs were higher than the PBS groups’ at every interval, and were significantly different both 4 and 6 weeks postoperatively. 40.e2
men (9.5%), posterior body from 5mm anterior of the mental foramen to the angle (23.8%), angle up to the mandibular foramen (23.8%), upper ramus above the mandibular foramen (0%) and the condylar region above the sigmoid notch (17.5%). Thirty fractures (47.6%) occurred in the mandible bearing the IAN. The majority of mandible fractures were treated by ORIF (69.8%), followed by CRF (27.0%) and no treatment (3.2%). Only cases treated with ORIF had neurosensory disturbance (NSD) and abnormal NST results (mild sensory impairment or worse), both preoperatively (40.9% NSD, 18.2% abnormal NST) and postoperatively (63.6% NSD, 40.9% abnormal NST). There were no instances of post-treatment NSD or abnormal NST results in cases treated with CRF or no treatment. Of the 63 mandible fracture sides, 19 (30.2%) had NSD and 8 (12.7%) had abnormal NST results before treatment. At 1 week after treatment, 28 (44.4%) had NSD and 18 (28.6%) had abnormal NST results. Of 22 mandible fractures in the mandible anterior to 5mm from the mental foramen, 18.2% had NSD with no abnormal NST results before treatment; 40.9% had NSD and 18.2% had abnormal NST results after treatment. In comparison, of 30 posterior mandible sides bearing the IAN, 50% had NSD and 26.7% had abnormal NST results before treatment (of these, 87.5% had a fracture gap of 5 mm or more). After treatment, 63.3% had NSD and 46.7% had abnormal NST results; all were cases treated with open reduction and rigid fixation. Further follow-up is still ongoing. Conclusion: Clinically severe mandible fractures were more likely to be treated with rigid fixation and were more likely to have a higher incidence of IAN injury. Fractures of the mandible body, angle and ramus bearing the IAN had a higher risk of subjective NSD associated with a higher incidence of abnormal objective NST results. References Thurmuller P, Dodson TB, Kaban LB. Nerve injuries associated with facial trauma. Natural history, management, and outcomes of repair. Oral Maxillofac Surg Clin North Am 2001: 13: 283-293 Zuniga JR, Essick GK. A contemporary approach to the clinical evaluation of trigeminal nerve injuries. Oral Maxillofac Surg Clin North Am 1992: 4: 353-367 Zuniga JR, Meyer RA, Gregg JM, Miloro M, Davis LF. The accuracy of clinical neurosensory testing for nerve injury diagnosis. J Oral Maxillofac Surg 1998: 56: 2-8
Regeneration of Facial Nerve Defects Using a Silicone Tube Filled With Dental Pulp Cells Ryo Sasaki, DDS, Tokyo Women’s Medical University, 8-1 Kawada-cho, Shinjyuku-ku, Tokyo, 162-8666, Japan (Uchiyama H; Ogiuchi H) AAOMS • 2007
Oral Abstract Session 8 Statement: Nerve autografting is the most common surgical procedure currently used for repairing facial nerve defects caused by traffic accidents or malignant tumor resections (Kumar et al, 2002). A number of recent studies have shown the effectiveness of tubulation as an alternative therapy to that of nerve autografting for peripheral nerve gaps (Matsumoto et al, 2000). For large peripheral nerve defects, tubulation alone is limited to nerve regeneration. It has been reported that tubulation using brain-derived neural progenitor cells or Schwann cells promotes nerve regeneration (Murakami et al, 2003). However, use of these neural cells from other neural tissues has potentially serious clinical complications along with ethical considerations. Therefore, we focused on the use of dental pulp as a new cell source for such artificial nerves. Dental pulp is derived from the neural crest, included fibroblasts, and Schwann and stem cells. It is assumed that these cells have an important role in peripheral nerve regeneration. Therefore, we investigated whether transplanted dental pulp cells in a facial nerve gap promoted nerve repair. Materials and Methods: Adult Sprague-Dawley (SD) rats were anesthetized by isoflurane using an original nasal mask. A 7-mm defect was prepared in the buccal branch of the facial nerve. Dental pulp cells were isolated from adult SD rat maxillary incisors containing a transgene-expressing green fluorescent protein (GFP). The defect was bridged with a 10-mm silicone tube filled with GFP-positive dental pulp cells (1.0⫻105) embedded in type I collagen gel. Both the proximal and distal stump of the nerve was inserted about 1.0-mm into the tube and connected with 2 sutures of 9-0 nylons under microscopy. Method of Data Analysis: The regenerated nerve was evaluated by immunohistologic study. Results: 14 days after surgery, a GFP-positive regenerated nerve was observed in the silicone tube. The regenerated nerve included Tuj1-positive axons and RECA1positive vessels. These results suggested that transplanted dental pulp cells may differentiate into supportive cells and may support axonal regeneration. Conclusion: When dental pulp cells are transplanted into a large peripheral nerve defect, they may contribute to the promotion of axonal regeneration. Dental pulp may be a viable source of easily obtainable cells for potential use in facial nerve regeneration. References K. Matsumoto et al, Peripheral nerve regeneration across an 80-mm gap bridged by a polyglycolic acid (PGA)-collagen tube filled with laminin-coated collagen fiber: a histrogical and electrophysiological evaluation of regenerated nerves, Brain Res, 868, 3 P. Kumar et al, Cross-face nerve graft with free-muscle transfer for reanimation of the paralyzed face: a comparative study of the singlestage and two-stage procedures, Plast Reconstr. Surg, 109, 451-462, 2002 T. Murakami et al, Transplanted neuronal progenitor cells in a peripheral nerve gap promote nerve repair, Brain Res, 974, 17-24, 2003
AAOMS • 2007
Effect of Recombinant Human BDNF Gene Therapy on the Nerve Regeneration in Rat Sciatic Nerve Transection Kang-Mi Pang, Korea (Lee JH; Jeon SH; Pang KM; Myoung H; Hwang SJ; Seo BM; Choi JY; Choung PH; Kim MJ) Statement: In cases of transection injury to the peripheral nerve, end-to-end anastomosis of the transected nerve segments is the traditional and widely used method. However, full functional recovery is seldom obtained, and regeneration takes a long time, so many attempts have been made to use neurotrophic factors to improve nerve regeneration. Among them, BDNF (brainderived neurotrophic factor) is known to be associated with survival and regeneration of the central and peripheral nervous systems. The purpose of this study is to verify the hypothesis that recombinant human BDNF-adenovirus injection into transected and repaired rat’s sciatic nerves can enhance nerve regeneration in vivo. Materials and Methods: Recombinant human BDNFadenovirus was obtained from professor Yun-Hee Kim in Kyunghee University and was multiplied and purified in our laboratory. Six-week-old male Sprague-Dawley male rats (n⫽40) were anesthetized i.p. and their left sciatic nerves were exposed and isolated. After transection 5mm distal from the sciatic notch, either 3l of PBS (PBS group, control group) or 3l of recombinant human BDNF-adenovirus (BDNF-Ad group, experimental group) was injected, and one epineural suture with 10-0 nylon was made. The rat’s gait was analyzed at 2, 4, 6, 8 and 10 weeks postoperatively, and their sciatic function index (SFI) was calculated. An electrophysiologic study was completed 5 and 10 weeks postoperatively, and nerve conduction velocity and peak voltage were obtained. After the electrophysiologic study, segments of the sciatic nerves were harvested including the end-to-end anastomosis site. Three longitudinal specimens were used for immunofluoroscent study with NF 200 (neurofilament 200), and the last specimens were prepared for crosssection in each group. Axon density, total axon count and myelin thickness of both proximal and distal stumps were calculated. All data were expressed as mean ⫾ SEM. The statistical significance of the difference between the experimental and control groups at the same interval was analyzed by a Mann-Whitney U test using the StatView II program (version 5.0.01 The SAS Institute, USA). Method of Data Analysis: n/a Results: 1. Gait analysis showed that the BDNF-Ad group’s SFIs were higher than the PBS groups’ at every interval, and were significantly different both 4 and 6 weeks postoperatively. 40.e2