Unicystic Ameloblastoma Involving the Mandible: A Case Report

Unicystic ameloblastoma (UA) refers to those cystic lesions that show clinical, radiographic, or gross features of a mandibular cyst, but on histological examination show a typical ameloblastomatous epithelium lining part of the cyst cavity, with or without luminal and/or mural tumour growth. UA is believed to be the less aggressive than the solid or multicystic ameloblastomas. We present a case report of 40 year old male patient with UA involving the entire body of the mandible.

Procedimentos cirúrgicos e protéticos para o implante dentário de corpo único: uma opção social / Clinical surgical and prosthodontic procedures for the single-body dental implant system: a social option

Os implantes de corpo único, também conhecidos como implantes de ativação imediata, atravessaram o período da história de transição entre a Implantodontia convencional à osseointegrada, adequando-se no que se refere ao tipo de metal (titânio) e tratamento de superfície. Porém, o protocolo protético manteve-se a mercê da criatividade de cada cirurgião-dentista. Por meio de uma transferência, com analogia aos casquetes de moldagens sobre os dentes naturais, esse relato de caso clínico abordou desde a cirurgia até a prótese, mostrando ser uma opção viável no arsenal de procedimentos implantodônticos

Single-body implants, also known as immediate activation fixtures, has survived to the transition period between conventional and contemporary osseointegration philosophies. However, all prosthodontic procedures depends on individual creativity. This clinical case report demonstrates all surgical steps and a clinical procedure similar to the resin coping impression technique over natural teeth that can be a viable option for the implant practitioner

The Availability of Autogenous Bicortical Iliac Bone Graft in Anterior Cervical Interbody Fusion

STUDY DESIGN: Retrospective study. OBJECTIVES: To demonstrate the fusion rate, degree of subsidence and donor site morbidity of anterior cervical interbody fusion with autogenous bicortical iliac bone graft and anterior cervical locking plate. SUMMARY OF THE LITERATURE REVIEW: In anterior cervical discectomy and fusion with autogenous tricortical iliac bone graft, a large percentage of patients report chronic donor site pain. MATERIALS AND METHODS: Retrospective research was done for 39 patients who underwent anterior cervical interbody fusion with autogenous bicortical iliac bone graft, from January 2006 to July 2011, with a follow up period of longer than 1 year. Fusion rates and subsidece of the graft is estimated with radiographs. Neck pain and donor site pain was estimated with visual analogue scale (VAS) and dysfunction was estimated with the neck disability index (NDI). RESULTS: A 95% of patients who underwent anterior cervical interbody fusion with autogenous bicortical iliac bone graft revealed definitive fusion with little amount of subsidence. The mean VAS score was 0.7 on the donor site and the mean NDI score was 3.8 at the final visit. There was excellent clinical outcome without complication at the donor site or the recipient site. CONCLUSIONS: Anterior cervical interbody fusion with autogenous bicortical iliac bone graft showed high fusion rates and minimal subsidence with excellent clinical outcomes. Therefore, bicortical iliac bone graft is an effective operational procedure in anterior cervical interbody fusion.

Fractures of the Proximal Fifth Metatarsal: Percutaneous Bicortical Fixation

BACKGROUND: Displaced intraarticular zone I and displaced zone II fractures of the proximal fifth metatarsal bone are frequently complicated by delayed nonunion due to a vascular watershed. Many complications have been reported with the commonly used intramedullary screw fixation for these fractures. The optimal surgical procedure for these fractures has not been determined. All these observations led us to evaluate the effectiveness of percutaneous bicortical screw fixation for treating these fractures. METHODS: Twenty-three fractures were operatively treated by bicortical screw fixation. All the fractures were evaluated both clinically and radiologically for the healing. All the patients were followed at 2 or 3 week intervals till fracture union. The patients were followed for an average of 22.5 months. RESULTS: Twenty-three fractures healed uneventfully following bicortical fixation, with a mean healing time of 6.3 weeks (range, 4 to 10 weeks). The average American Orthopaedic Foot & Ankle Society (AOFAS) score was 94 (range, 90 to 99). All the patients reported no pain at rest or during athletic activity. We removed the implant in all cases at a mean of 23.2 weeks (range, 18 to 32 weeks). There was no refracture in any of our cases. CONCLUSIONS: The current study shows the effectiveness of bicortical screw fixation for displaced intraarticular zone I fractures and displaced zone II fractures. We recommend it as one of the useful techniques for fixation of displaced zone I and II fractures.

A Retrospective Comparative Study of Internal Fixation with Contoured Plate Using Bicortical Screw Versus a Double Plate in Comminuted Olecranon Fractures / 대한정형외과학회잡지

PURPOSE: To analyze the clinical result of a contoured plate fixation using a bicortical screw and a double plate fixation in the surgical treatment of an adult's comminuted olecranon fracture. MATERIALS AND METHODS: A total of 22 patients were classified by Mayo classification as Type IIB (17) and Type IIIB (5). All patients enrolled in the study were treated between July 2002 and September 2009. Twelve patients were operated on using the contoured plate internal fixation using a bicortical screw procedure classified as group 'A'. The 10 patients operated on by a double plate fixation were classified as group 'B'. The Mayo elbow performance score was used to compare postoperative clinical results based on total points in 4 categories: pain, range of motion, articular stability, and articular function. RESULTS: The clinical results of using the Mayo elbow performance score of group 'A' were that 10 scored in the 'excellent' range and 2 scored in the 'good' range the following: in group 'B' were in the excellent range and 3 were in the good range. Both groups showed satisfactory results. Postoperative elbow exercises in group 'A' commenced 7.8 (5-14) days on average, postoperatively. For 'B' group, post-operative elbow exercises began 4.5 (3-7) days following the operation. With regard to the exercise and the range of elbow motion, group 'A' averaged 113.5 degrees and group 'B' averaged 112 degrees. After surgery, the average durations until the bone union were 3.8 (2.4-5.6) months for group 'A' and 4 (2.5-5) months for group 'B', respectively. CONCLUSION: There was no significant difference in the clinical results between patients treated with the contoured plate internal fixation using a bicortical screw or the internal fixation using a double plate in the surgical treatment of adults with comminuted olecranon fracture or dislocation. Therefore, both types of operative approach are acceptable.

Hybrid fixation in the bilateral sagittal split osteotomy for lower jaw advancement

Miniplate and screw fixation has been widely used in bilateral sagittal split osteotomy, but some issues remain unclear concerning its lack of rigidity when compared to Spiessl's bicortical technique. This paper demonstrates the hybrid fixation technique in a case report. A 34-year-old female patient underwent a double jaw surgery with counter-clockwise rotation of the mandible fixed using the hybrid fixation technique. The patient evolved well in the postoperative period and is still under follow up after 14 months, reporting satisfaction with the results and no significant deviation from the treatment plan up to now. No damage to tooth roots was done, maxillomandibular range of motion was within normality and regression of the inferior alveolar nerve paresthesia was observed bilaterally. The hybrid mandibular fixation is clearly visible in the panoramic and cephalometric control radiographs. It seems that the hybrid fixation can sum the advantages of both monocortical and bicortical techniques in lower jaw advancement, increasing fixation stability without significant damage to the mandibular articulation and the inferior alveolar nerve. A statistical investigation seems necessary to prove its efficacy.

The effect of various thread designs on the initial stability of taper implants

STATEMENT OF PROBLEM: Primary stability at the time of implant placement is related to the level of primary bone contact. The level of bone contact with implant is affected by thread design, surgical procedure and bone quality, etc. PURPOSE: The aim of this study was to compare the initial stability of the various taper implants according to the thread designs, half of which were engaged to inferior cortical wall of type IV bone (Group 1) and the rest of which were not engaged to inferior cortical wall (Group 2) by measuring the implant stability quotient (ISQ) and the removal torque value (RTV). MATERIAL AND METHODS: In this study, 6 different implant fixtures with 10 mm length were installed. In order to simulate the sinus inferior wall of type IV bone, one side cortical bone of swine rib was removed. 6 different implants were installed in the same bone block following manufacturer's recommended procedures. Total 10 bone blocks were made for each group. The height of Group 1 bone block was 10 mm for engagement and that of group 2 was 13 mm. The initial stability was measured with ISQ value using Osstell mentor(R) and with removal torque using MGT50 torque gauge. RESULTS: In this study, we found the following results. 1. In Group 1 with fixtures engaged to the inferior cortical wall, there was no significant difference in RTV and ISQ value among the 6 types of implants. 2. In Group 2 with fixtures not engaged to the inferior cortical wall, there was significant difference in RTV and ISQ value among the 6 types of implants (P < .05). 3. There was significant difference in RTV and ISQ value according to whether fixtures were engaged to the inferior cortical wall or not (P < .05). 4. Under-drilling made RTV and ISQ value increase significantly in the NT implants which had lower RTV and ISQ value in Group 2 (P < .05). CONCLUSIONS: Without being engaged to the inferior cortical wall fixtures had initial stability affected by implant types. Also in poor quality bone, under-drilling improved initial stability.

Comparision of Non-locking Monocortical and Bicortical Screw System for Anterior Cervical Fusion and Plating in Degenerative Cervical Spondylosis

OBJECTIVE: Non-locking bicortical screw and locking monocortical screw system have usually been used in anterior cervical spine fusion and plating. The purpose of this study is to evaluate the differences in stability and safety between the non-locking bicortical and monocortical screw-plate system. METHODS: The authors reviewed 135 cervical spondylotic patients who underwent anterior cervical fusion from Jan. 1995 through Jun. 2002. The patients were separated into two groups: Group 1. consisted of 68 patients (male: 55, female 13 and mean age: 50.5years) treated with non-locking bicortical screw system, Group 2. consisted of 67 patients (male 50, female 17, mean age: 59.6 years) treated with non-locking monocortical screw system. The mean follow-up duration was 50 months (from 9 to 101 months). A comprehensive evaluation between two groups were made. RESULTS: There were no graft material related complications in both groups. But instrument related complications were 1 case of screw breakage and 1 case of screw loosening in group 1 and 1 case of screw loosening in group 2. Mean time for plate and screw fixation was less required in group 2 than group 1. Fusion had occurred in all patients of both groups. CONCLUSION: Non-locking monocortical screw fixation can be recommended for anterior cervical fusion and plating in degenerative disease, making the procedure quicker, easier, and safer compare with non-locking bicortical screw.

Long-Term Follow-up of Posterior Pedicle Instrumentation and Anterior Lumbar Fusion using a bicortical Iliac Allograft / 대한정형외과학회잡지

PURPOSE: To evaluate long-term results of an anterior lumbar fusion with posterior instrumentation using a bicortical iliac allograft. MATERIALS AND METHODS: Fifty-one patients underwent anterior lumbar fusion with posterior instrumentation using an iliac allograft. This study included 28 patients and 37 levels, and was followed for at least 5 years. Clinical and radiological results were evaluated. RESULTS: Bony fusion was obtained in 92% of the levels and excellent or good clinical results were achieved in 82% of the patients. Mean intervertebral disc space of 10.7 mm preoperatively was increased to 14.6 mm postoperatively and became 12 mm at final follow-up. Ascrew breakage was noted in one patient. CONCLUSION: Our data suggest that bicortical iliac allograft is a satisfactory graft material and produces acceptable clinical and radiological results in anterior lumbar fusion with posterior instrumentation. However, with respect to fusion quality the allograft should be a substitute for autograft in selected case.

Comparisons of Unicortical and Bicortical Lateral Mass Screws in the Cervical Spine: Safety vs Strength

INTRODUCTION: The purpose of this study was to analyze the safety, pullout strength and radiographic characteristics of unicortical and bicortical screws of cervical facet within cadaveric specimens and evaluate the influence of level of training on the positioning of these screws. METHODS: Twenty-one cadavers, mean 78.9 years of age, underwent bilateral placement of 3.5mm AO lateral mass screw from C3-C6(n=168) using a slight variation of the Magerl technique. Intraoperative imaging was not used. The right side(unicortical) utilized only 14mm screws(effective length of 11mm) while on the left side to determine the length of the screw after the ventral cortex had been drilled. Three spine surgeons(attending, fellow, chief resident) with varying levels of spine training performed the procedure on seven cadavers each. All spines were harvested and lateral radiographs were taken. Individual cervical vertebrae were carefully dissected and then axial radiographs were taken. The screws were evaluated clinically and radiographically for their safety. Screws were graded clinically for their safety with respect to the spinal cord, facet joint, nerve root and vertebral artery. The grades consisted of the following categories: "satisfactory", "at risk" and "direct injury". Each screw was also graded according to its zone placement. Screw position was quantified by measuring a sagittal angle from the lateral radiograph and an axial angle from the axial radiograph. Pull-out force was determined for all screws using a material testing machine. RESULTS: Dissection revealed that fifteen screws on the left side actually had only unicortical and not bicortical purchase as intended. The majority of screws(92.8%) were satisfactory in terms of safety. There were no injuries to the spinal cord. On the right side(unicortical), 98.9% of the screws were "satisfactory" and on the left side(bicortical) 68.1% were "satisfactory". There was a 5.8% incidence of direct arterial injury and a 17.4% incidence of direct nerve root injury with the bicortical screws. There were no "direct injuries" with the unicortical screws for the nerve root or vertebral artery. The unicortical screws had a 21.4% incidence of direct injury of the facet joint, while the bicortical screws had a 21.7% incidence. The majority of "direct injury" of bicortical screws were placed by the surgeon with the least experience. The performance of the resident surgeon was significantly different from the attending or fellow(p<0.05) in terms of safety of the nerve root and vertebral artery. The attending's performance was significantly better than the resident or fellow(p<0.05) in terms of safety of the facet joint. There was no relationship between the safety of a screw and its zone placement. The axial deviation angle measured 23.5+/-6.6 degrees and 19.8+/-7.9 degrees for the unicortical and bicortical screws, respectively. The resident surgeon had a significantly lower angle than the attending or fellow(p<0.05). The sagittal angle measured 66.3+/-7.0 degrees and 62.3+/-7.9 degrees for the unicortical and bicortical screws, respectively. The attending had a significantly lower sagittal angle than the fellow or resident(p<0.05). Thirty-three screws that entered the facet joint were tested for pull-out strength but excluded from the data because they were not lateral mass screws per-se and had deviated substantially from the intended final trajectory. The mean pull-out force for all screws was 542.9+/-296.6N. There was no statistically significant difference between the pull-out force for unicortical(519.9+/-286.9N) and bicortical(565.2+/-306N) screws. There was no significant difference in pull-out strengths with respect to zone placement. CONCLUSION: It is our belief that the risk associated with bicortical purchase mandates formal spine training if it is to be done safely and accurately. Unicortical screws are safer regardless of level of training. It is apparent that 14mm lateral mass screws placed in a supero-lateral trajectory in the adult cervical spine provide an equivalent strength with a much lower risk of injury than the longer bicortical screws placed in a similar orientation.

Biomechanical analysis of mandibular bilateral sagittal split ramus osteotomy with bicortical screws internal fixation / 实用口腔医学杂志

Objective: To study the mandibular bilateral sagittal split ramus osteotomy (BSSRO) with bicortical screws rigid internal fixation(RIF) with the three-dimensional finite element method, and supply directions for clinic practice.Methods:CT scanned technology and the finite element software (Ansys) were used to establish the three-dimensional finite element model of BSSRO with bicortical screws RIF. The stress distribution of the mandible and the RIF and the displacement of split mandible were calculated under three kind of occlusion situation.Results:Under the same kind of occlusion situation, the stress and displacement of the split mandible with single upper screws fixation was higher than that with the reverse "L" screws fixation, the stress and displacement of the split mandible with 2.0 mm diameter screws fixation was higher than that with 2.7 mm diameter screws fixation. With the same kind of fixation method, the stress and the displacemen of the mandible under the incisor occlusion was the highest.Conclusion:The fixation distance, position, distribution angle of the bicortical screws all have effects on the fixation stability. The patient should avoid the incisor occlusion after the surgery.

Anterior Ceervical Interbody Fusion: Comparison Study between Simple Fusion, Locked and Non-locked Plating Systems

The use of metallic plate and screws in the anterior cervical fusion has become generally acceptable and popular. Mainly, there are two different plating systems available. However, there has been few attempts to compare their clinical results with and without a plating system or between two different systems in a single series of clinical study. The authors reviewed 117 patients who underwent anterior cervical fusion during the period of January 1992 to September 1996. Simple fusion without a plating system was applied in 55 cases(group 1), a bicortical non-locked plate screw system in 25(group 2), and a monocortical locked plate screw system in 37(group 3). The average follow-up period was 13. 2 months. In group 1, twenty-two patients(40%) with fracture-dislocation or corpectomy required a rigid brace such as halo brace and Minerva cast for 3 months postope ratively and seven patients(13%) experienced graft complications, mainly graft extrusion. In group 2 and 3, the patients required only soft b races for 4 to 8 weeks and no patients experienced serious graft complications like ones in group 1 but, instead two patients with screw breakages, two back-outs and one non-union were observed. In comparison of the clinical complications such as hoarsness, there were no significant differences between the groups. In conclusion, the plating system in anterior cervical fusion appears to be safe despite the facts that mo re technical demands are required during surgery. It also provides better postoperative stability in the spine and permits earlier ambulation without a rigid brace. A monocortical locked plate screw system appears to have less hardware failures and better su rgical results than a bicortical non-locked plate screw system.

Comparative Efficacy Study between Monocortical and Bicortical Screws in Anterior Cervical Fusion

The purpose of the study was to assess the role of two types screws(bicortical screws with 3.5mm diameter and monocortical screws with 4.5mm diameter) in anterior cervical spinal fusion. Seventy patients surgically treated on the same surgeon was retrospectively reviewed. All patients were managed as the same technique(modified Smith-Robinson technique) and the same non-locking plate system(Top plate system), but the bicortical screws were used in 40 patients(Group 1) and the monocorical screws in 30 patients(Group 2). The overall fusion rate during the 3 months follow up at least was to be satisfied on the both groups. The complication from the Group 2 was never seen but Group 1 was observed in 5 patients; one as slip of grafted bone, 2 as screw loosening, 1 as psychologic intolerance and 1 as CSF leakage. The monocortical screw was considered to be superior than bicortical screw and was related to the screw diameter.

The Efficacy of the Unicortical Screw in the Anterior Cervical Fusion of the Degenerative Cervical Spine Disease

Anterior cervical fusion without internal fixation destabilizes an already unstable spine and can result in tenuous bone graft stability and potential for incorporation. Anterior fusion of cervical spine with screw-plates is gaining in popularity in the management of anterior cervical spine instability. Eighty six cases that underwent anterior fusion with or without internal fixation and autogenous iliac bone graft were compared and analyzed. The pathologies included 40 cases of cervical disc disease, 43 of cervical spondylosis and 3 of ossification of posterior longitudinal ligament. Changes in the alignment of the total cervical spine and of the fused segment were evaluated in both groups. Dislodgement of the grafted bone, which was observed in 2 of 11 cases in the nonplate group, was not seen in the plate group. Hardware failure was developed in 3 of 24 cases in the bicortical group, but not in 51 cases in the unicortical group. Alignment of the cervical spine was corrected and relatively well manintained in the plate group compared with the nonplate group. We concluded that a unicortical screw fixation was superior than a bicortical screw and a fusion without plating system could not keep a cervical lordotic curve in the treatment of the degenerative cervical disease.

Anatomical Safe Zone of Sacral Ala for Ventrolateral Sacral(S1) Screw Placement: Re-evaluation of Its Effectiveness

Among the various sacral fixation techniques used to enhance the strength of fixation, S1 screw placement in the sacrum is the most common method. Ventrolateral S1 screw placement through the sacral ala has been used alone or in combination with a medially-directed screw in the S1 pedicle to enhance pull-out resistance. Although the anatomical safe zone was identified, there is a risk of neurovascular injury particularly when the enhancement of fixation strength requires bicortical purchase. The purpose of this cadaver study is to re-evaluate the previous anatomical safe zone when using an S1 screw laterally directed toward the sacral ala. After dissecting the lateral safe zone of sacral ala in 12 human cadavers, K-wires were intentionally inserted deep into this zone. Each "safe" angle to the center of the safe zone was measured and the degree of risk to neurovascular structures was recorded on the basis of the distance in millimeters from the tips of the penetrating K-wires. The results are as follows: the mean safe angle to the center of the anatomical safe zone was 33.5degrees+/-9.3(20-50). Between 20 and 50 degrees, the range of safe angle was too wide. The distance between the tip of the K-wire and the sacroiliac joint, lumbosacral trunk, obturator nerve was 4.8mm+/-1(4-7.5), 6.8mm+/-1(6-9.5) and 6.8mm+/-3.2(0-10) respectively, while the anterior height between sacral cortex and lumbosacral trunk, internal iliac vein was 0mm and 2.1mm+/-1.8(0-5) respectively. In 29% of cases, the iliolumbar artery, the first branch of the internal iliac artery, abnormally crossed the middle of the safe zone. The sacroiliac joint, lumbosacral trunk, internal iliac vein and iliolumbar artery were at risk from laterally-directed S1 screws. This study shows that bicortical placement of S1 screws into the sacral ala presents unnecessary risks to neurovascular structures. It is concluded that the previous anatomical safe zone for bicortical S1 screw placement into the sacral ala was not surgically safe, and when lumbosacral fixation surgery is planned, operative techniques other than bicortical screw placement should be considered.

Anterior Cervical Fusion: A Retrospective Analysis of 152 Cases

Anterior cervical fusion has enjoyed an increasing acceptance and frequency of utilization in the treatment of symptomatic degenerative, traumatic, and neoplastic disorders. Since the introduction of plate systems, cervical fusion with fixation has become popularized. We present our experiences of 152 cases of cervical fusion in degenerative and traumatic lesions, focusing on their surgical results and complications, along with our opinions about the various plate systems we used. Between March 1993 and May 1996, 152 patients with symptomatic degenerative and traumatic cervical lesions between C3-4 and C7-T1 levels were treated with anterior cervical fusions. These patients were retrospectively studied according to their medical records and radiological studies. A comparison between various plate systems were also done. There were 110 men and 42 women, aged from 21 to 77 years. Mean follow up period was 17 months. Mean fused segments were 1.4. Various plate systems were used: Caspar plate system in 14 patients; Top plate in 102; Orion plate in 21; and none in 15. Dislodgement of bone graft, screw loosening, and fusion failure that required reoperation were occurred in 8 cases. None of them were initially treated with unicortical type screws. Asymptomatic esophageal perforation was developed in one case among them. In conclusion, anterior cervical fusion with screw plate system can be carried out with acceptable complication rate. Although relative follow up period was short, we concluded that the locking type screw plate system was superior than the classic bicortical screw system in their procedural simplicity, unnecessary penetration of posterior cortex, and elimination of the fear for the neurological complication.