Biomechanical Study of Posterior Dynamic Fixation at Atlantoaxial Joints / 医用生物力学

Objective To evaluate the influence of dynamic fixation (rotating and sliding pedicle screws) on stability of the atlantoaxial joint. Methods A series of in vitro biomechanical tests were performed using six fresh adult cervical spines (occipital bone-C4 segment) to simulate different conditions in surgery， including the intact state, the injury state, rigid fixation, rotating pedicle screw fixation, sliding pedicle screw fixation. The repeated measurement design was employed, and under intact, injury and different fixation states, the pure moment of 1.5 N·m in flexion-extension, left-right lateral bending, left-right axial rotation directions were applied using the spinal testing machine. The movement of atlantoaxial spine was measured consecutively by three-dimensional （3D） measurement system in order to analyze the range of motion (ROM) and neutral zone (NZ) of atlantoaxial joints. Results Under injury state, ROM of atlantoaxial joints was significantly larger than that under intact state during flexion, extension, lateral bending and rotation, leading to the instability of atlantoaxial joints. ROM of fixation segments was significantly reduced during flexion, extension, lateral bending and rotation after rigid and dynamic fixation. Compared with rigid fixation, dynamic fixation showed a significant ROM increase during lateral bending. NZs of fixation segments after dynamic fixation were significantly reduced. There were no significant ROM differences between rigid fixation and dynamic fixation. Conclusions The stability of atlantoaxial joints by dynamic fixation during flexion, extension and rotation was comparable to that by rigid fixation, but weaker during lateral bending. Dynamic screw fixation can maintain the relative stability of atlantoaxial joints.

Orthognathic surgery for patients with fibrous dysplasia involved with dentition / 대한악안면성형재건외과학회지

BACKGROUND: Fibrous dysplasia (FD) is characterized by the replacement of normal bone by abnormal fibro-osseous connective tissue and typically treated with surgical contouring of the dysplastic bone. When dysplastic lesions involve occlusion, not only is surgical debulking needed, orthognathic surgery for correction of dentofacial deformity is mandatory. However, the long-term stability of osteotomized, dysplastic bone segments is a major concern because of insufficient screw-to-bone engagement during surgery and the risk of FD lesion re-growth. CASE PRESENTATION: This case report reviewed two patients with non-syndromic FD that presented with maxillary occlusal canting and facial asymmetry. Le Fort I osteotomy with recontouring of the dysplastic zygomaticomaxillary region had been performed. The stability of osseous segments were favorable. However, dysplastic, newly formed bone covered the previous plate fixation site and mild bony expansion was observed, which did not influence the facial profile. Including the current cases, 15 cases of orthognathic surgery for FD with dentition have been reported in the literature. CONCLUSION: The results showed that osteotomy did not appear to significantly reduce the long-term stability of the initial fixation insufficiency of the screw to the dysplastic bone. However, based on our results and those of the others, long-term follow-up and monitoring are needed, even in cases where the osteotomized segment shows stable results.

Complicaciones en cirugía ortognática: conceptos actuales y revisión de la literatura / Complications in orthognathic surgery: current concepts and review of the literature

La cirugía ortognática es el tratamiento de elección para corregir deformidades dentofaciales congénitas o adquiridas en menor cantidad de casos, estas técnicas pueden ser aplicadas en la resección de tumores y apnea del sueño. Usualmente se lleva a cabo entre la segunda y tercera década de vida. Dentro de los benefi cios que se obtienen se incluyen una mejor función masticatoria, resultados estables en discrepancias dentofaciales severas y un mejor aspecto estético facial. Sin embargo, aun el cirujano más experimentado puede enfrentar complicaciones, entre las que destacan las vasculares, técnicas, nerviosas, periodontales, infecciosas, oftálmicas, de oclusión, psicológicas y necrosis ósea. Algu-nas de estas complicaciones pueden discutirse en detalle con el paciente antes del procedimiento. A pesar de lo anterior, el tratamiento de cirugía ortognática puede ser considerado como un procedimiento seguro. Las complicaciones se pueden dividir en preoperatorias, transoperatorias y postoperatorias, teniendo en las dos últimas una mayor incidencia.

Orthognathic surgery is the treatment of choice for the correction of congenital or acquired dentofacial deformities; in a minority of cases, the techniques involved can be applied to tumor resection and to treat sleep apnea. This type of surgery is usually performed between the second and third decades of life. The benefi ts obtained include a better chewing function, stable results in severe dentofacial anomalies, and improved facial aesthetics. However, even the most experienced surgeon can encounter a range of issues, most notably vascular, technical, ner-vous, periodontal, infectious, ophthalmic, psychological, those related to occlusion, and bone necrosis. Some of these can be discussed in detail with the patient prior to the procedure. Nevertheless, orthognathic surgery treatment can be considered a safe procedure. Complications can be classifi ed into three types: preoperative, intraoperative, and postoperative, the latter two being the most common.

Uso de tornillos bicorticales de rosca invertida para fijación rígida en osteotomías sagitales de rama mandibular / Use of bicortical screws thread inverted rigid fixation in sagittal ramus osteotomy

La osteotomía sagital de rama mandibular bilateral, es un procedimiento que se considera seguro, predecible y estable utilizado para corregir las anomalías dentofaciales de origen esquelético únicas o en combinación con otras osteotomías faciales. La fijación de los segmentos osteotomizados se realiza mediante el uso de material de osteosíntesis no reabsorbible de material tipo titanio, en su mayoría con tornillos bicorticales de longitudes mayores con respecto a los tornillos convencionales utilizados para fijación rígida ósea facial, sin embargo en algunos casos, la oclusión definitiva posterior a la cirugía ortognatica no es similar al planeamiento prequirúrgico planeado, debido a factores asociados a la fijación rígida con tornillos bicorticales, Se ha observado en una amplia cantidad de osteotomías sagitales bilaterales de rama mandibular durante la fijación con tornillos bicorticales, movimientos de tipo indeseado por el operador, a menudo observando máxima intercuspidacion en la zona posterior derecha y leve mordida abierta en la zona posterior izquierda; de acuerdo a la biomecánica mandibular dichos movimientos ocurren por la presencia del eje de la rosca de los tornillos bicorticales utilizados para la fijación rígida que en su mayoría están dirigidos en sentido de las agujas del reloj. El propósito de este artículo es proponer el uso de tornillos bicorticales de rosca invertida para la fijación de la osteotomía sagital mandibular contrarrestando el efecto indeseado observado en la oclusión definitiva de pacientes sometidos a osteotomías sagitales bilaterales de rama mandibular, en paciente sometidos a cirugía ortognatica monomaxilar y bimaxilar para la corrección de anomalías dentofaciales.

The bilateral sagittal ramus osteotomy is a procedure that is considered safe, predictable and stable dentofacial used to correct skeletal abnormalities unique origin or in combination with other facial osteotomies. Osteotomized fixing segments is performed using non-resorbable osteosynthesis material type titanium material, mostly bicortical screws with longer lengths compared to conventional screws used for rigid fixation facial bone, however in some cases, the subsequent final occlusion orthognathic surgery is not similar to preoperative planning planned due to factors associated with rigid fixation with bicortical screws, it has been observed in a wide number of bilateral sagittal osteotomy of ramus during fixation with bicortical screws movements unwanted by the operator type, often observing maximum intercuspation in the right posterior open bite and mild in the left rear area; according to the mandibular biomechanics such movements occur by the presence of the thread axis of the bicortical screws used for rigid fixation which mostly are directed in the direction of clockwise. It is the purpose of this review article, proposing the use of bicortical screws reverse threaded for fixing the mandibular sagittal osteotomy counteracting the undesirable effect observed in the final occlusion patients undergoing bilateral sagittal osteotomy of ramus in patients undergoing surgery monomaxilar bimaxillary orthognathic and for the correction of dentofacial anomalies.

Biomechanical analysis on the fixation of mandibular condyle with sagittal fracture by double plates in 3 ways / 实用口腔医学杂志

Objective:To analyze the biomechanical stress distribution on the sagittal fractured of the mandibular condyle(SFMC) fixed by double plates in 3 different ways.Methods:The fixation finite element models with double straight plates(SS),one straight and one L-form plates(SL),and double L-form plates(LL)were established.The biomechanical stresses on condyle were calculated with finite element analysis.Results:In the model of SS fixation the maximum equivalent stress (MES),maximum total displacement (MTD)and maximum total corner(MTC)of condylar stump were 525.475 MPa,0.902 2 mm and 0.260 1°;MES,MTD,and MTC on fractured free-end were 4.425 MPa,0.882 7 mm and 0.019 9°,respectively.In the model of SL fixation MES,MTD and MTC on condylar stump were 1 135 MPa,0.9367 mm and 0.126 1°;MES,MTD and MTC on fractured free-end were 2.656 MPa,0.887 1 mm and 0.016 9°,respectively.In the model of LL fixation MES,MTD and MTC on condylar stump were 2 208 MPa,0.923 8 mm and 0.172 2°;MES,MTD and MTC on fractured free-end were 14.66 8 MPa,0.876 6 mm and 0.018 1°,respectively.Conclusion:Double L plates fixation is a proper way for SFMC.

Abordaje retromandibular transparotídeo con fijación rígida en fracturas subcondíleas / Retromandibular transparotid approach with rigid fixation in subcondylar fractures

Introducción: el manejo terapéutico de las fracturas subcondíleas ha sido controversial, demostrando su reducción abierta y fijación rígida excelentes resultados, por lo que se realizó este estudio del abordaje retromandibular transparotídeo con fijación rígida en fracturas subcondíleas. Objetivo: caracterizar demográficamente la muestra estudiada; describir los resultados clínicos y radiográficos obtenidos e identificar accidentes y complicaciones. Material y métodos: se ejecutó un estudio de casos en 25 pacientes del total de pacientes con fracturas subcondíleas que acudieron al servicio de Cirugía Máxilofacial del Hospital Universitario "Miguel Enríquez", 2002-2011. Se realizó abordaje retromandibular transparotídeo y fijación rígida; se analizaron variables demográficas, variables clínicas y radiográficas, accidentes y complicaciones. Se evaluaron cronológicamente. Resultados: predominaron pacientes con edades entre 15-24 años (40%) y el sexo masculino (80%); las fracturas unilaterales (80%) y las subcondíleas altas (40%). A los 7 días, la máxima apertura bucal promedió 39 mm y 3 mm de deflexión. Se registró 100% de reducción anatómica y oclusión estable. Conclusiones: el abordaje retromandibular transparotídeo con fijación rígida es un método adecuado de tratamiento de las fracturas subcondíleas con excelentes resultados estéticos y funcionales.

Introduction: controversy exists regarding the management of mandibular condyle fractures, but the open approach with rigid fixation has been successful. A study was done about Retromandibular transparotideal approach with rigid fixation in subcondylar fractures. Objective: to characterize demographically the studied sample, to describe the obtained clinical and radiographical results, to identify associated accidents and complications. Material and methods: a case series study was carried out in 25 patients of the total of patients with subcondylar fractures diagnosis who attended to the Maxillofacial Departament, University Hospital "Miguel Enríquez", between 2002-2011. The sample was subjected to surgical treatment by means of retromandibular approach and rigid fixation. The studied variables were: demographical, clinical and radiographical variables; accidents and complications. The patients were evaluated chronologically. Results: patients among 15-24 years (40%), masculine sex (80%), unilateral fractures (80%), and high subcondylar (40%) prevailed. In 7 days the average value of maximum buccal opening was 39 mm and 3 mm of deflexion. 100% of the cases registered anatomical reduction. Conclusions: the transparotideal retromandibular approach with rigid fixation is an appropriate method of treatment of sub-condylar fractures with excellent aesthetic and functional results.

Tooth in the line of fracture: Its prognosis and its effects on healing.

Aims and Objective: The aim of this prospective study was to compare the postoperative results of mandibular angle fracture cases treated by open reduction and internal fixation wherein the third molar in the line of fracture was preserved in one group while it was extracted in the second group. Materials and Methods: Group I consisted of 30 patients in which the mandibular third molar in the line of fracture was preserved and group II consisted of 24 patients in which it was extracted following specific criteria. Various parameters like postoperative healing, infection, occlusion, tooth vitality, and mobility were graded numerically. Statistical analysis using a t-test was done. Data were expressed as mean±SD and a probability (P) value of <0.05 was considered significant. Results: The presence of infection with pain and tenderness was higher in group I. Osteogenesis was higher in group I till the end of the third week but the difference was not significant later. Discrepancy in occlusion was more in group II. Mobility of tooth decreased and status of periodontal tissue improved significantly with time. In the tooth involved, the return of vitality and decrease in pain/tenderness was significant after 1 week and continued till 24 weeks to normalcy. Two teeth showed mild root resorbtion and none showed ankylosis. Conclusion: Postoperative occlusal discrepancy is less but infection is higher when the tooth in the line of fracture is preserved as compared to when it is removed. More than half of the teeth in the fracture line show complete recovery within a period of 6 months to 1 year. Despite the risk of an increase in the rate of complications, the tooth in the line of fracture should be preserved for its merits.

Lisfranc Injury Repair with the TightRope(TM) Device: A Case Report / 대한족부족관절학회지

Lisfranc injury is complex and difficult to treat. Making the correct diagnosis and achieving an anatomical reduction are important factors in regard to achieving a favorable outcome with this injury. We describe a new technique that we have found to be useful for stabilizing Lisfranc injury. This method is relatively fast and simple, and it provides non-rigid fixation. Also, it eliminates the need for implant removal. To date, we have achieved predictable results for stabilizing and treating this injury with the use of a TightRope(TM) Device, instead of traditional interfragmental screw fixation. In this report, we describe a case in which this method was used with satisfactory short-term results.

Avaliação de seis tipos de osteossíntese usando uma miniplaca dos sistemas regular ou locking para fixação de osteotomia sagital de mandíbula: estudo in vitro / An in vitro biomechanical evaluation of six types of osteosynthesis using one regular or locking plate to fixate the sagittal split ramus osteotomy in mandible

O objetivo da presente investigação foi verificar a resistência ao deslocamento de seis formas diferentes de osteossíntese, usando uma miniplaca para a estabilização da osteotomia sagital da mandíbula. Material e Método: Foram realizadas osteomias sagitais em 30 hemimandíbulas de poliuretano. Um avanço de 4 mm do segmento ósseo distal foi executado e os grupos foram divididos de acordo com a placa utilizada para fixação: Grupo 1 -placa 4 furos regular; Grupo 2 -placa 4 furos Locking; Grupo 3 -placa 6 furos regular; Grupo 4 - placa 6 furos Locking; Grupo 5 -placa sagital 6 furos regular e, Grupo 6 -placa sagital 6 furos Locking. O teste mecânico de três pontos com força compressiva sobre o segundo molar foi realizado e a carga de força foi gerada por uma máquina universal de ensaio Instron até que 3 mm de deslocamento dos segmentos fossem verificados. Os valores obtidos em kN das forças compressivas produzidas para o deslocamento foram submetidos ao teste de Análise de Variância (P<0,01) e ao Teste estatístico de Tukey para a comparação entre grupos (P<0,05). Reultados: A placa sagital locking mostrou maior resistência ao teste biomecâncio que as placas regulares de 4 e 6 furos e não apresentou diferença para a placa sagital regular e placa locking 4 furos. Dentre os 3 Grupos de melhor resultado, 2 pertencem ao sistema locking. Conclusões: Para a fixação da osteotomia sagital de mandíbula empregando-se apenas uma miniplaca, é recomendado o uso da placa sagital 6 furos do sistema locking, da placa sagital 6 furos regular ou da placa linear 4 furos locking porque apresentam maior resistência ao deslocamento. Não foi comprovado do ponto de vista estatístico vantagem na resistência ao deslocamento das placas do sistema locking em relação ao sistema regular...

Purpose: The aim of the present study was to evaluate the efficacy of six types of osteosynthesis using one miniplate for sagittal split osteotomy in mandible. Material and Methods: The osteotomy was done in 30 polyurethane hemi-mandibles. After 4 mm advancement of the distal segment 6 different groups were create using 2.0 screw system: group 1 -4-hole regular plates; group 2 -4-hole Locking; group 3 -6-hole regular plate; group 4 -6-hole locking plates, group 5 -6-hole regular sagittal plate; group 6 -6-hole locking sagittal plate. A 3-point biomechanical test model with compression loads were applied at the second inferior molar site using the INSTRON machine until 3mm displacement was reached. The load for the displacement were gathered and compared using statistics Tukey’s test (P<0.05). Results: The 6-hole sagittal locking plate group followed by the 6-hole sagittal regular plate and 4-holes locking plate are more stable than the others groups and among the 3 best results, 2 groups belong to locking system. Conclusion: It is possible to suggest to the surgeons that use only one plate to fixate the bilateral sagittal split osteotomy to choose the 6-hole locking or regular sagittal plate or 4- bole locking plate because they offer more resistance to displacement. The locking system did not show better statistical results beside the numeric results indicate it...

A Study on Bone-Contact to Inter-Segmental Length Ratio of Rigid Fixation Screws used in Bssro for Mandibular Setback

OBJECTIVE: To evaluate the ratio between bone-contact length and inter-segmental length of the rigid fixation screw used in bilateral sagittal split ramus osteotomy (BSSRO) for mandibular setback. MATERIAL AND METHODS: Records of 40 patients with Class III malocclusion were selected. 20 of them had BSSRO, while the other 20 had BSSRO with maxillary LeFort I osteotomy. All of the patients had three noncompressive bicortical screws inserted at the gonial angle through transcutaneous approach. Two screws were inserted antero-posteriorly above inferior alveolar nerve and one screw was inserted below. The lengths of bone-contact and that of inter-segmental part were measured using cone-beam computed tomography. Ratio between these two measured lengths was calculated. RESULTS: Both bone-contact and inter-segmental lengths were longer in BSSRO group than in BSSRO with maxillary LeFort I osteotomy group. Ratio of bone-contact to inter-segmental length was lower in BSSRO group than in BSSRO with Lefort I group. Both bone-contact and inter-segmental lengths were longer at the antero-superior position than at the inferior position. However, their ratio showed little difference. CONCLUSION: This study suggest that stability of screws in BSSRO group was greater than in BSSRO with Lefort I group. Stability of screws at the antero-superior position was greater than at the inferior position. Ratio of bone-contact to inter- segmental lengths was 0.2 in average.

Clincal analysis of skeletal stability after BSSRO for correction of skeletal class III malocclusion patients with anterir open bite

This study was conducted to patients visited oral maxillo-facial surgery, KNUH and the purpose of the study was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction treated by skeletal Class III malocclusion patients with open bite versus non-open bite. This retrospective study was based on the examination of 40 patient, 19 males and 21 females, with a mean age 22.3 years. The patients were divided into two groups based on open bite and non-open bite skeletal Class III malocclusion patients. The cephalometric records of 40 skeletal Class III malocclusion patients (open bite: n = 18, non-open bite: n = 22) were examined at different time point, i.e. before surgery(T1), immediately after surgery(T2), one year after surgery(T3). Bilateral sagittal split ramus osteotomy was performed in 40 patients. Rigid internal fixation was standard method used in all patient. Through analysis and evaluation of the cephalometric records, we were able to achieve following results of post-surgical stability and relapse. 1. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in maxillary occlusal plane angle of pre-operative stage(p>0.05). 2. Mean vertical relapses of skeletal Class III malocclusion patients with open bite were 0.02+/-1.43mm at B point and 0.42+/-1.56mm at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, 0.12+/-1.55mm at B point and 0.08+/-1.57mm at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in vertical relapse(p>0.05). 3. Mean horizontal relapses of skeletal Class III malocclusion patients with open bite were 1.22+/-2.21mm at B point and 0.74+/-2.25mm at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, 0.92+/-1.81mm at B point and 0.83+/-2.11mm at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in horizontal relapse(p>0.05). 4. There were no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in post-surgical mandibular stability(p>0.05). and we believe this is due to minimized mandibular condylar positional change using mandibular condylar positioning system and also rigid fixation using miniplate 5. Although there was no significant relapse tendency observed at chin points, according to the Pearson correlation analysis, the mandibular relapse was influenced by the amount of vertical and horizontal movement of mandibular set-back(p=0.05, r>0.304).

A Case Report of RED II Distraction Osteogenesis and Early Rigid Fixation by Minimal Invasive Approach Le Fort III Osteotomy in Crouzon's Disease

PURPOSE: Rigid external distraction(RED) is a highly effective technique for correction of maxillary hypoplasia in patients with cleft or syndromic craniosynostosis. Despite many advantages of RED, it also has the problem of relapse as the conventional advancement surgery. Bicoronal approach, that is the common approach to gain access to the craniofacial skeleton, had some morbidity, such as hair loss, sensory loss, wide scar and temporal hollowing. We present our clinical experience of RED distraction with minimal invasive approach and early rigid fixation to overcome these disadvantages. METHODS: A 27-year-old female patient with Crouzon's disease underwent Le Fort III osteotomy and RED device application through the minimal invasive direct skin incisions. After the latent period of 5 days, distraction was undertaken until proper convexity and advancement were obtained. During the rigid retention period, inflammation occurred on the right cheek, and proper conservative managements were done including continuous irrigation. To maintain the stability of distraction, early rigid fixation was undertaken on the osteotomy sites through another skin incisions. Preoperative and postoperative orthodontic treatments were performed. Serial photographs and cephalometric radiographs were obtained preoperatively, after distraction and 6 months after distraction. RESULTS: The cephalometric analysis demonstrated postoperatively significant advancement of the maxilla and improvement of facial convexity. After 6-month follow-up period, the maxilla was stable in the sagittal plane and no relapse was found. Facial scars were not noticeable and other deformity and morbidity did not occur. CONCLUSION: This effective and stable technique will be a good alternative for the patients who need large amount of distraction and for adult patients with severe maxillary hypoplasia or syndromic craniosynostosis.

A Case Report of RED II Distraction Osteogenesis and Early Rigid Fixation by Minimal Invasive Approach Le Fort III Osteotomy in Crouzon's Disease

PURPOSE: Rigid external distraction(RED) is a highly effective technique for correction of maxillary hypoplasia in patients with cleft or syndromic craniosynostosis. Despite many advantages of RED, it also has the problem of relapse as the conventional advancement surgery. Bicoronal approach, that is the common approach to gain access to the craniofacial skeleton, had some morbidity, such as hair loss, sensory loss, wide scar and temporal hollowing. We present our clinical experience of RED distraction with minimal invasive approach and early rigid fixation to overcome these disadvantages. METHODS: A 27-year-old female patient with Crouzon's disease underwent Le Fort III osteotomy and RED device application through the minimal invasive direct skin incisions. After the latent period of 5 days, distraction was undertaken until proper convexity and advancement were obtained. During the rigid retention period, inflammation occurred on the right cheek, and proper conservative managements were done including continuous irrigation. To maintain the stability of distraction, early rigid fixation was undertaken on the osteotomy sites through another skin incisions. Preoperative and postoperative orthodontic treatments were performed. Serial photographs and cephalometric radiographs were obtained preoperatively, after distraction and 6 months after distraction. RESULTS: The cephalometric analysis demonstrated postoperatively significant advancement of the maxilla and improvement of facial convexity. After 6-month follow-up period, the maxilla was stable in the sagittal plane and no relapse was found. Facial scars were not noticeable and other deformity and morbidity did not occur. CONCLUSION: This effective and stable technique will be a good alternative for the patients who need large amount of distraction and for adult patients with severe maxillary hypoplasia or syndromic craniosynostosis.

Open reduction and fixation in acute laryngeal trauma under endoscopic guidance

Acute laryngeal trauma is a great challenge for the otoloaryngologist. Early recognition, accurate evaluation and proper treatment may be crucial to immediate survival and long-term function. Objective:To describe an endoscopically-guided open reduction and adaptation plate fixation of an acute laryngeal fracture secondary to vehicular accident. Methods: a. Study Design: Surgical Innovation/ Case Report b. Setting:Tertiary Hospital in Metro Manila Results: Post-operative follow-up showed good vocal fold function and arytenoid position, with no food regurgitation, signs of aspiration or penetration on fiberoptic endoscopic evaluation of swallowing Conclusion: Endoscopic guidance allows higher magnification minimizing iatrogenic mucosal damage during manipulation. (Author)

Rigid fixation and space maintenance by titanium mesh for reconstruction of the premaxilla

Treatment of mandibular compound-comminuted fractures

Stability after Surgical Correction of Mandibular Prognathism Using Bilateral Sagittal Split Ramus Osteotomy with Rigid Fixation

Sagittal split ramus osteotomy(SSRO) has become one of the most popular procedure for correction of mandibular prognathism. Rigid fixation is favored for its stability and patient comfort. But there were few data presented about skeletal stability and factors contributing to relapse for sagittal split ramus osteotomy with rigid fixation. From August 1997 to August 2002, eleven patients, who underwent sagittal split osteotomy with rigid fixation, were studied. Patients with genioplasty or any other orthognatic surgical procedures were excluded from sample. Lateral cephalograms were analyzed before surgery, 1 month after surgery, and 12 months after surgery. The mean amount of surgical setback was 6.29 mm at pogonion and the mean amount of skeletal relapse was 1.29 mm at pogonion. The mean postoperative horizontal change of soft tissue pogonion was 5.66 mm posteriorly, vertical change of menton was 1.83 mm superiorly, and angular change of ramus inclination was 5.88 degree increased. The mean amount of postoperative movement was 1.9 mm anteriorly at soft tissue pogonion, 2.13 mm superiorly at menton, 0.8 degree was decreases at ramus inclination. The amount of skeletal relapse is related to the amount of setback. The results of this study present that the bilateral sagittal split osteotomy with rigid fixation has many advantages and stable procedure for the correction of mandibular prognathism.

Comparative Study of Skeletal Relapse According to the Fixation Method after BSSRO for Mandibular Setback

Treatment of Degenerative Lumbar Instability with Semi-Rigid Isolock System

For degenerative lumbar instability, various spinal instrumentations have been used to relieve clinical symptom and to stabilize the spine. Most of them are rigid fixation which cause a postfusion instability at adjacent segment with high incidence. It creates a highly susceptible region(neo-hinge) between fixed rigid segment and nonfixed mobile segment. Eventually acceleration of degenerative change in adjacent segment is resulted with clinical deterioration. To avoid of postfusion instability after rigid fixation, a semi-rigid fixation system which has a intermediate transitional zone is developed. In 98 patients with degenerative lumbar instability, semi-rigid fixation which had a damper in the middle of plate were performed with CH titanium cage. Angular instability in lateral dynamic X-ray was improved in all case immediately after operation. Translational instability also much improved. But no degenerative change or instability in adjacent segment(neo-hinge disc) or overlying disc within fusion segment during follow up period of average 16 months. Excellent and good clinical results were achieved in 90.8% of patients and the solid bone fusion was occurred in 98.9%.

Clinical observation on the efficacy of surgical treatment of mandibular condylar fracture by a direct approach / 实用口腔医学杂志

Objective:To explore the therapeutic efficacy of a new access to internal rigid fixation for mandibular condylar fracture. Methods: 7 patients with 9 unilateral mandibular condylar fractures were treated with preauricular beeline incisions. The two trunks of facial nerve were dissected and separated along the surface of the superficial temporal veins. Mandibular ramus periosteum was dissected. The fracture segments were reduced and fixed under sufficient exposure. Results: This operation access provided a sufficient exposure and was convenient for reduction and fixation. All the patients recovered effectively.Conclusion: This surgical approach is one of the feasible methods for reduction and fixation of mandibular condylar fracture.