Application of an augmented reality tool for maxillary positioning in orthognathic surgery – A feasibility study

BACKGROUND: An augmented reality tool for computer assisted surgery named X-Scope allows visual tracking of real anatomical structures in superposition with volume rendered CT or MRI scans and thus can be used for navigated translocation of bony segments. METHODS: In a feasibility study X-Scope was used in orthognathic surgery to control the translocation of the maxilla after Le Fort I osteotomy within a bimaxillary procedure. The situation achieved was compared with the pre-operative situation by means of cephalometric analysis on lateral and frontal cephalograms. RESULTS: The technique was successfully utilized in 5 patients. Maxillary positioning using X-Scope was accomplished accurately within a range of 1mm. The tool was used in all cases in addition to the usual intra-operative splints. A stand-alone application without conventional control does not yet seem reasonable. CONCLUSION: Augmented reality tools like X-Scope may be helpful for controlling maxillary translocation in orthognathic surgery. The application to other interventions in cranio-maxillofacial surgery such as Le Fort III osteotomy, fronto-orbital advancement, and cranial vault reshaping or repair may also be considered.     

Periapical radiographic techniques during endodontic diagnosis and treatment

The objective of this article is to describe various radiographic projections which can be used during endodontic therapy. Changes to the angulation of the X-ray beam in relation to the teeth and film can help diagnosis and treatment by producing images which provide additional information not always visible on radiographs taken with standard angulations. For example, changes in angulation can be useful to determine the number and curvature of roots and canals, to identify superimposed roots and to distinguish between anatomical landmarks and apical pathology. Although use of such techniques increases the diagnostic yield of films, it must be appreciated that such views lead to images that are less distinct because of inherent image distortion. Nevertheless, use of the various techniques during endodontics can provide substantial benefit for clinicians in their daily practice.     

Mechanical Testing of Seven Fixation Methods for Generation of Compression Across a Midtarsal Osteotomy: A Comparison of Internal and External Fixation Devices

The purpose of this study was to assess 7 methods of fixation for a midtarsal osteotomy. Polyurethane foam models (N = 6) and cadaver specimens (N = 4-7) were used to examine the force generated by the different constructs of fixation. A midtarsal osteotomy was performed on each specimen in the test groups. The osteotomies were fixated either with 2 parallel 0.062-in Kirschner wires and 40-mm-long, 4-mm partially threaded, cancellous, cannulated titanium screws, an external ring fixator (frame), a frame with wires tensioned (tension), a frame with wires tensioned and compressed toward the osteotomy (tension and compression), a frame with tension, compression, and parallel Kirschner wires, or a frame with tension, compression, and two 4.0 cannulated parallel screws, respectively. Each model was fixated, and the force generated by the construct across the osteotomy was recorded via the use of pressure-sensitive film. Statistical analysis of the data in the polyurethane foam group determined that the use of frame with tension, compression, and two 4.0 parallel cannulated screws was statistically superior to 1) frame, 2) frame with tension, 3) 2 parallel Kirschner wires, 4) two 4.0 cannulated parallel screws, and 5) frame with tension and compression. A cadaver study determined that the frame with tension, compression, and 2 parallel Kirschner wires was statistically superior to 1) frame and 2) two parallel Kirschner wires. These findings suggest that there is a difference in the force generated by the type of fixation construct across a midtarsal osteotomy.     

Osteotomy of the tibial tubercle in complex primary total knee replacement

Objective  Stiffness and severe deformity pose a major challenge in total knee arthroplasty. Numerous techniques have been described to gain exposure and improve knee flexion. Tibial tubercle osteotomy provides excellent and safe exposure of the joint, although mechanical and wound complications have been reported. Materials and methods  We present a series of 32 consecutive complex primary total replacements where an osteotomy of the tibial tubercle was utilised. Results  The patients had a mean follow-up of 2 years and 11 months. Following the procedure, with the exception of one case complicated with deep infection, all of the patients had improved clinically. The mean postoperative range of motion had increased to 102° (give P value < 0.005) and there were no cases of delayed union or non-union. A mechanical complication related to technique occurred in one patient; there were no other cases with a postoperative extension lag. Conclusion  In this challenging population group, we have found a tibial tubercle tuberosity osteotomy to greatly facilitate exposure without compromising the clinical and radiographic outcome.     

颏形态综合分析在颏部水平截骨整形术中的应用

目的探讨分析小颏畸形的颏部形态特征及其在颏部水平截骨整形手术应用中的效果。方法通过头颅正侧位X线头影测量分析12例小颏畸形患者的颏部形态,按测量值与正常值之间的差值,计算截骨段移动范围,手术采用颏部水平截骨整形手术方法。结果12例患者均按照术前预测值移动截骨段,术后头颅正侧位X线头影测量结果与术前预测值相近,治疗效果满意。结论通过头颅正侧位X线头影测量分析小颏畸形的特点,精确计算截骨段的移动范围和方向,是保证颏部水平截骨整形术达到良好美容效果的基础。     

Correction of hallux valgus deformity with distal soft tissue realignment and proximal metatarsal osteotomy

Abstract Fifty moderate to severe hallux valgus deformities were corrected with a distal soft tissue realignment and proximal crescentic metatarsal osteotomy. With an average follow-up of 5.6 years, 40 feet (80%) were pain free and 42 (84%) caused no functional limitation. The average hallux valgus angle improved from 38.2° preoperatively to 12.4° at follow-up. The average intermetatarsal angle improved from 15.4° to 6.8°. The arch of motion of the first metatarsophalangeal joint was 75° preoperatively and 62° at follow-up. According to the AOFAS scoring system, 29 results (58%) were excellent, 14 (28%) good, 2 (4%) fair and 5 (10%) poor. The 5 poor results were attributed to recurrence of hallux valgus (2 cases), stiffness (1), hallux varus (1) and malunion of the osteotomy in dorsiflexion (1). The incidences of hallux varus and malunion in dorsiflexion were 8% and 14%, respectively. This technique is valuable in correction of moderate to severe hallux valgus deformities.     

GIEBEL系统在胫骨高位截骨术中的应用

[目的]探讨GIEBEL内固定系统固定的胫骨高位截骨术治疗膝内翻畸形的效果。[方法]对19例31膝,平均53.5岁的膝内翻患者进行评价。术前内翻畸形平均12.29°;膝关节症状以内侧间室疼痛为主。不伴有其他关节间室病变。对患膝进行精确的胫骨高位截骨术后应用GIEBEL系统内固定截骨端。手术前后拍摄双下肢负重位全长X线片,测量内翻角、机械轴线和解剖轴线。记录内外侧关节间隙距离的差值以及关节活动度。同时进行Lysholm评分。术后对患者进行主观满意度调查。[结果]对19例患者平均随访22个月。术后1例腓总神经一过性麻痹,2例切口脂肪液化延迟愈合。截骨处至术后12~16周均骨性愈合。测量矫正角度平均12.32°。3例患者残留膝前疼痛和关节绞锁症状。在随访期间膝内外侧间隙无明显退变加重。手术效果优良率为89.5%。84.2%患者对手术效果表示满意。除膝关节活动度外,Lysholm评分、内外关节间隙差以及内翻角度在手术前后差异均有统计学显著性差异。[结论]GIEBEL系统可有效地固定胫骨高位截骨术截骨端,对轻中度膝关节内翻畸形患者固定强度大,骨愈合率高。