双侧升支矢状劈开截骨后退下颌术后骨的稳定性的研究

目的：探讨双侧升支矢状劈开截骨术（BSSRO）后退下颌骨以钢丝结扎固定两骨段加颌间固定术后骨的稳定性，了解导致复发的有关因素。方法：双侧下颌升支矢状劈开截骨手术后退下颌的患者14例，于手术前1周，手术后1周，术后6个月分别拍摄定位头颅侧位片及许勒位X线片，用于测量下颌移动的距离及确定下颌骨髁状突的位置。结果：双侧下颌升支矢状劈开截骨后退术后，6个月的复发率为27.2%，多元逐步回归分析示下颌后退的距离与复发相关。结论：BSSRO后退下颌骨的距离越大，术后下颌骨向前移位的可能越大。     

CT三维重建下探讨BSSRO术舌侧水平截骨线与骨劈开效果的关系

目的:应用CT三维重建来探讨双侧下颌骨矢状劈开截骨术舌侧水平截骨线与骨劈开效果的关系,为下颌骨矢状劈开截骨术舌侧水平截骨位置的选择提供指导。方法:选择17例双侧下颌骨前突患者(34例),经过下颌骨矢状劈开截骨术,术后应用三维重建观测水平截骨线及劈开效果。结果:只有10.87%的劈开结果理想(符合Hunsuck描述),54.35%的劈开效果较理想,32.61%的穿过了下颌管,4.35%穿过了其它部位。劈开的效果直接受水平截骨位置的影响(P<0.01)。结论:三维CT在评价下颌骨矢状劈开截骨术效果方面是有效的工具,为下颌骨矢状劈开截骨术选择舌侧水平截骨线位置提供重要数据,并能降低不良劈开的发生率。     

与下颌升支矢状劈开截骨相关的下颌管解剖研究

目的 研究下颌管在下颌骨内的走行和位置关系，为下颌升支矢状劈开截骨手术提供指导。方法 选用30具完整的干燥下颌骨标本，分别在第二磨牙远中的垂直线，磨牙后三角尖至下颌角连线及下颌孔下3mm呈冠状锯开下颌骨，观察测量下颌管的解剖位置。结果 下颌管是下颌骨睁骨松质内较薄的骨密质骨管。下颌管在下颌第二磨牙后缘切面的位置靠内侧型占87％，中间型占13％；在连线切面的住置内侧型占92％，中间型占8％；在下颌孔下3mm平面内侧型占98％，外侧型占2％。越接近下颌孔，烦侧骨皮质越厚。结论 了解下颌管在下颌骨内的位置及比邻关系，可避免下颌升支矢状劈开截骨中下齿槽神经血管束的损伤。     

骨支持式3D打印导板在上颌骨LeFortⅠ型截骨术中的应用

目的 探讨3D打印技术制作的截骨导板和再定位导板在上颌骨LeFortⅠ型截骨术中的应用效果。方法 选择8例因上颌发育不良行LeFortⅠ型截骨术的的患者为研究对象,所有患者均进行锥形束CT（CBCT）扫描并建立上颌骨三维模型,使用3D打印技术制作上颌骨截骨导板和再定位导板。所有手术均由同一名医生操作,术中使用截骨导板截骨和再定位导板固定上颌骨块。术后复查CBCT,测量6个标志点到3个基准平面的距离,比较术前虚拟手术与实际手术中上颌骨的位移误差,评估其用于正颌术中上颌骨截骨和再固定的准确性。结果 术后所有患者口内切口均Ⅰ期愈合,无明显并发症。位移误差均值最大为1.35 mm,是左上磨牙点到冠状平面的位移误差;标准差最大为0.85,标准误最大为0.30。位移误差均为临床所接受范围。结论 3D打印技术制作的截骨导板和再定位导板有助于安全、准确地完成上颌骨LeFortⅠ截骨术。     

下颌升支矢状劈开截骨术后下颌骨短期稳定性的三维分析

目的:本研究利用三维测量方法分析下颌骨在下颌升支矢状劈开截骨术后短期内的复发趋势.方法:收集在北京大学口腔医院接受正颌-正畸联合治疗并行下颌升支矢状截骨手术的患者共49例,分为下颌前徙患者22例,下颌后退患者27例,收集术前4 d(T0)、术后4 d(T1)、术后4～6周(T2)、3个月(T3)的CBCT数据,利用计算机辅助设计软件Pro Plan进行三维头颅重建,建立坐标系并测量下颌骨相关指标.利用SPSS 20.0软件对T1、T2时的测量结果进行配对t检验.结果:在接受下颌升支矢状劈开截骨术的患者中,下颌前徙患者的下颌骨在B点、Pg点存在水平向的复发趋势,下颌平面存在顺时针旋转的倾向.下颌后退患者的下颌骨在B点存在水平向的复发趋势,Pg点存在水平向和垂直向的复发趋势.结论:下颌升支矢状劈开截骨术后术后下颌骨在短期内存在复发倾向,但在临床可接受范围内.     

下颌升支矢状劈开截骨术后退和前徙下颌骨对下颌运动范围的影响

作者对接受下颌升支矢状劈开截骨术患者（下颌骨后退１１例，下颌骨前徙１０例）手术前自下颌运动范围进行了测量，并对颞下颌关节进行了临床检查。发现在术后６个月时，后退组患者的张口度已恢复到术前水平，前徙组患者的张口度仍低于术前，且差异有高度显著性（Ｐ＜０．０１），术后两组患者下颌前伸和侧向运动（左右）均无明显变化。提示下颌升支矢状劈开截骨术后退下颌骨对患者张口度影响较小，且术后恢复较快。     

3D打印截骨导板辅助赝复体术中修复BrownⅡ类缺损的精准度评价

目的 设计制作3D打印截骨导板用于赝复体术中修复BrownⅡ类缺损,评价其临床应用的精准度.方法 8例因肿瘤致BrownⅡ类缺损患者纳入研究,术前设计制作3D打印截骨导板及赝复体,术中在截骨导板引导下完成手术,即刻戴入赝复体修复缺损,将术前虚拟计划与术后CBCT融合,对整体及局部区域行偏差分析评价手术精准度.应用SPS...     

数字化技术在半侧颌骨肥大治疗中的应用1例报道

目的:探讨半侧颌骨肥大(hemimandibular hyperplasia,HMH)的数字化设计和3D打印板的应用。方法 :对1例活跃期半侧颌骨肥大畸形的患者实施了Le Fort I型截骨术、左侧下颌升支矢状劈开截骨术、口内入路右侧升支垂直截骨术合并髁突切除术、右侧下颌下缘轮廓成形术等综合手术。临床流程是先采集螺旋CT数据,并对牙模激光扫描,利用Supervirtual软件进行虚拟手术设计,通过3D打印板,在手术中应用。完整保存了患者的临床资料和放射线检查。结果:3D打印的板精确、有效,手术时间缩短,手术效果好,患者面部中线一致,面型对称。结论:本例报道显示:在半侧颌骨肥大的综合手术治疗中,数字化手术设计和3D打印板是有效可行的。     

正畸-正颌手术联合矫治骨性开(牙合)的长期稳定性研究

目的 研究正畸-正颌手术联合矫治骨性开15年后的骨性以及牙性变化.方法 本研究样本为10例成年骨性开患者,所有患者均采用正畸-正颌手术联合矫治.上颌采用了Le Fort I型截骨术,下颌采用了双侧升支矢状劈开截骨术(BSSO).选择患者在正畸治疗前(T1)、治疗后(T2)以及正颌手术后平均15年(T3)的头颅侧位片进行...     

计算机辅助模型外科设计及虚拟[牙合]板的临床应用

目的：通过计算机辅助软件进行正颌手术模型外科设计，经快速原型技术制作[牙合]板，探讨该[牙合]板的临床应用价值。方法：15例颌面畸形需要正颌手术的患者均进行全头颅三维CT扫描（层厚0．625mm），将DICOM格式的CT数据输入电脑软件Simplant CMF（Materialise Medical，Leuven，Belgium）。通过软件对头颅模型进行上下颌骨的分离、截骨线的设计、截骨、骨块移动等操作，收集并输出数据，经快速原型机制作[牙合]板（虚拟[牙合]板）。同时，每例患者还进行传统石膏模型外科以及传统[牙合]板制作。术中首先利用虚拟[牙合]板进行骨块的移动和固定，然后应用传统[牙合]板检验骨块的新位置，验证虚拟[牙合]板的临床实用性。结果：15例患者中．4例单颌手术（双侧下颌支矢状劈开术）、10例双颌手术（LeFortⅠ型整体截骨术＋双侧下颌支矢状劈开术）以及1例双颌手术（LeFortⅠ型分块截骨术＋双侧下颌支矢状劈开术）。手术中，12例患者的虚拟[牙合]板完全符合临床要求。3例患者（包括1例双侧下颌支矢状劈开术和2例LeFortⅠ型整体截骨术＋双侧下颌支矢状劈开术）的虚拟[牙合]板与传统[牙合]板之间有部分偏差，遂通过传统[牙合]板进行骨块的重新固定。结论：计算机辅助设计可完成LeFortⅠ型整体（或分块）截骨术和双侧下颌支矢状劈开术的模型外科，虚拟[牙合]板基本可实现传统[牙合]板的功能。通过对软件的进一步熟悉、更多病例的积累，计算机辅助模型外科可能取代传统的石膏模型外科。     

Functional and radiographic long-term results after bad split in orthognathic surgery

Bilateral sagittal split osteotomy (BSSO) is a standard procedure in orthognathic surgery. The aim of the present study was to perform a matched pair analysis (bad sagittal split versus regular sagittal split) regarding the functional and radiographic long-term results after BSSO. Of 110 cases of mandibular hypoplasy treated with BSSO, 7 cases of bad sagittal splits (Group A) were selected, clinically examined and matched to 7 cases where no bad split occurred (Group B). The Research Diagnostic Criteria for Temporo Mandibular Disorders (RDC/TMD), condylar morphology scale (CMS) and ramus height measurements using orthopantomograms were carried out in the follow-up period to observe the clinical and functional status and condylar resorbtion or remodelling. The mean follow-up time was 28.6 months. The RDC/TMD examination did not show a higher incidence of temporomandibular dysfunction, including pain or clicking in the bad split group. Patients without a bad split showed statistically significant (p<0.05) better mouth opening. The CMS measurements were comparable in both groups. When compared with regular splits, bad splits, if treated in an appropriate manner, have a good chance of functional success, although, some mandibular movements can be compromised.     

One year postoperative hard and soft tissue volumetric changes after a BSSO mandibular advancement

In this study, cone beam computed tomography (CBCT) and three dimensional (3D) stereophotogrammetry are used to compare the 3D skeletal and soft tissue changes caused by a bilateral sagittal split osteotomy (BSSO) 1 year after a mandibular advancement. Eighteen consecutive patients with a hypoplastic mandible were treated with a BSSO according to the Hunsuck modification. Preoperatively and 1 year postoperatively, a CBCT scan was acquired and a 3D photograph. The pre- and postoperative CBCT scans were matched using voxel based registration. After registration, the mandible could be segmented in the pre- and postoperative scans. The preoperative scan was subtracted from the postoperative scan, resulting in the hard tissue difference. To investigate the soft tissue changes, the pre- and postoperative 3D photographs were registered using surface based registration. After registration the preoperative surface could be subtracted from the postoperative surface, resulting in the overall volumetric difference. As expected, a correlation between mandibular advancent and volumetric changes of the hard tissues was found. The correlation between advancement and soft tissues was weak. The labial mental fold stretched after surgery. This study proved that using 3D imaging techniques it is possible to document volumetric surgical changes accurately and objectively.     

The role of cone beam computed tomography in the management of unfavourable fractures following sagittal split mandibular osteotomy

Cone beam computed tomography (CBCT) has been at the forefront of recent technological advances within the maxillofacial region. CBCT is useful in the accurate assessment and planning of patients undergoing orthognathic surgery. We propose that it also has a role in the post-operative evaluation of a subgroup of patients who have suffered complications at the time of surgery. We present two cases where unfavourable splits occurred during a bilateral sagittal split osteotomy (BSSO) of the mandible. Both cases were investigated post-operatively with CBCT with the aim of identifying the potential cause of the unfavourable split and to establish accurate localization of the condyle in the glenoid fossa following intra-operative attempts at proximal segment control. CBCT should be considered for evaluation of the mandible following an unfavourable split where it is deemed that plain radiographs would not provide adequate information.     

The Unfavourable Split: a novel classification and an 11-year retrospective study looking at alternative methods for management of this well-known complication

An unfavourable split is a well-known complication following a sagittal split osteotomy (SSO) of the mandible. Our aim was to analyse all unfavourable mandibular splits that had occurred when carrying out a SSO with the aim to design a classification which can facilitate management. We carried out a retrospective study analysing all orthognathic surgery from January 2010 until April 2021. Data surrounding unfavourable splits during this period were specifically analysed. Orthognathic surgery during this period was performed by a single OMFS unit with osteotomies performed by a single surgeon and their trainee. The dataset included 311 patients who underwent either a bilateral sagittal split osteotomy (BSSO) or a bimaxillary osteotomy. There were 225 bimaxillary osteotomies and 86 BSSOs. Twenty-one patients had unfavourable splits following their BSSO with a total of 22 out of 622 sagittal split osteotomies over this 11-year period. Bilateral unfavourable splits occurred in one patient. These results correlate to an incidence rate of 6.8% of unfavourable splits following SSO's in an 11-year period. The results reveal common patterns of unfavourable splits to suggest a simple classification based on our results. This can be applied to any unfavourable splits in SSO which then allows the clinician to proceed with surgery and prevent abandonment of the procedure. It is classified as follows: Type 1 fractures where the mandibular condyle is attached to the proximal fragment; Type 2 fractures whereby the mandibular condyle is attached to the tooth-bearing segment; Type 3 fractures are lingual cortex fractures. Each of these fracture types has a specific management protocol, which we recommend is used in all unfavourable splits.     

The role of cone beam computed tomography in the management of unfavourable fractures following sagittal split mandibular osteotomy

Abstract

Cone beam computed tomography (CBCT) has been at the forefront of recent technological advances within the maxillofacial region. CBCT is useful in the accurate assessment and planning of patients undergoing orthognathic surgery. We propose that it also has a role in the post‐operative evaluation of a subgroup of patients who have suffered complications at the time of surgery. We present two cases where unfavourable splits occurred during a bilateral sagittal split osteotomy (BSSO) of the mandible. Both cases were investigated post‐operatively with CBCT with the aim of identifying the potential cause of the unfavourable split and to establish accurate localization of the condyle in the glenoid fossa following intra‐operative attempts at proximal segment control. CBCT should be considered for evaluation of the mandible following an unfavourable split where it is deemed that plain radiographs would not provide adequate information.     

The effect of physical rehabilitation on mandibular function after ramus osteotomies

The efficacy of a systematic regimen of rehabilitation of mandibular function after ramus osteotomy was investigated. Forty-eight patients who had had either sagittal split ramus osteotomy to advance the mandible or intraoral vertical ramus osteotomy to retract the mandible were studied; 24 patients received rehabilitation and 24 did not. Pre- and postsurgical maximal mandibular opening, lateral and protrusive mandibular movements, maximum bite force, muscle fatigability, and clinical evaluation of the temporomandibular joints were compared between the two groups. Patients who underwent an intraoral vertical ramus osteotomy did not show a significant decrease in any of the parameters measured whether or not rehabilitation was used. However, patients who underwent sagittal split ramus osteotomies without subsequent rehabilitation had significant decreases (P less than 0.05) in mean mandibular opening and bite force as well as increases (P less than 0.05) in muscular fatigability compared with patients who underwent rehabilitation. These findings indicate the need for routine preoperative evaluation of mandibular and temporomandibular joint function and postsurgical physical rehabilitation after ramus osteotomies.     

Trigeminal nerve hypesthesia after sagittal split osteotomy in setback cases: correlation of postoperative computed tomography and long-term trigeminal somatosensory evoked potentials.

PURPOSE: We sought to assess the relationship of the inferior alveolar nerve to the osteotomy site after bilateral sagittal split osteotomy (BSSO) and to correlate the nerve osteotomy relationship as the cause of long-term postoperative hypesthesia. Patients and Methods: The subjects consisted of 28 patients with mandibular prognathism who underwent BSSO setback surgery. The distance between the ostectomized surface of the mandibular ramus and mandibular canal was measured and scored on a computed tomograph (CT). The relationship between this distance and the presence and degree or absence of trigeminal nerve hypesthesia was objectively evaluated by latency delay of the trigeminal somatosensory evoked potential (TSEP) records. RESULTS: Five of the 56 sides (8.9%) showed latency delays more than 1 year after the operations. Scored CT points between the canal and the split surface strongly correlated with TSEP latency recovery (Y = 1.716X + 41.2). CONCLUSIONS: This relationship between the canal and the osteotomy site is related to long-term hypesthesia in BSSO postoperatively.