Marginal and segmental mandibulectomy in patients with oral cancer: a statistical analysis of 106 cases.

PURPOSE: The treatment of oral squamous cell carcinoma may require mandibular resection to secure adequate margin. This bone resection often is segmental or marginal mandibulectomy. The purpose of this work was to evaluate the local control and survival after surgical treatment of oral cancer, according to these 2 different mandibular resection procedures. PATIENTS AND METHODS: We conducted a retrospective study of a 20-year cohort of 106 patients who underwent marginal or segmental mandibulectomy for oral cancer. All patients had a biopsy-confirmed diagnosis of squamous cell carcinoma involving either the floor of the mouth, mandibular gingiva, retromolar trigone, tongue, buccal mucosa, or oropharynx. The type of mandibular resection and treatment outcome were compared, using an univariate analysis by the Pearson chi(2) test, logistic regression model for multivariate analysis, and Kaplan-Meier method to determine survival. RESULTS: The 5-year observed survival rate was 60.35%. The presence of histologic mandibular invasion increased the local recurrence rate. Early tumor stages (P =.02) were found to be associated with decreased local recurrence rates. Our findings indicate that tumor stage and size of mandibulectomy are more important than the type of mandibulectomy in predicting histologic bone involvement. The cases treated with a greater than 4 cm bone resection showed a lower survival rate than those treated with less than 4 cm mandibulectomy (P =.01). Patients in advanced stages (P =.006) and those with surgical margin (P =.0001) or the bone (P =.003) affected by the tumor showed a statistically significant lower survival rate. However, no statistically significant differences were found between patients treated by marginal or segmental mandibulectomy. CONCLUSIONS: Among the prognostic factors studied, the status of the surgical resection margin, the bony involvement and the size of mandibulectomy affected the prognosis for oral carcinoma. Mandibular conservation surgery is oncologically safe for patients with squamous carcinoma in early stages. The marginal technique was not associated with worse prognosis.     

下颌骨矩形切除术术后并发病理性骨折临床分析

目的：分析与下颌骨矩形切除术术后并发病理性骨折的相关因素，为改进手术方式减少骨折发生提供依据。方法：74例口腔癌病例分别采直角形和曲线形截骨方法进行了下颌骨矩形切除术，术后曲面断层片检查，测量剩余下颌骨高度的最小值并观察有否病理性骨折。结果：5例并发病理性骨折，其中直角形截骨4例，骨折发生率为8．9％；典线形截骨1例，骨折发生率为3．4％。术后并发病理性骨折的病例下颌骨剩余骨段高度最小值为0．96cm(SD,0.03)。骨折均发生于截骨区远中部。结论：保留下牙槽动脉血供．剩余下颌骨高度保留在1cm以上对预防病理性骨折有重要意义；曲线形截骨具有良好的生物力学结构以及较好的术后形态和生理功能，可减少术后骨折发生。     

Mandibular invasion in oral squamous cell carcinoma: investigation by clinical examination and orthopantomogram

Assessing the relationship of oral squamous carcinoma with the mandible prior to definitive therapy poses a perplexing problem for the head and neck oncologist. We carried out a prospective open study of 51 (21 female and 30 male; mean age of 53.4 years) patients undergoing mandibular resections for oral squamous cell carcinoma to examine the incidence of mandibular bone invasion and to assess the predictive capabilities of clinical and radiological examination in detecting bone involvement. A detailed clinical examination was followed by radiographic evaluation of mandible for bone invasion. After resection, the mandible was sectioned serially at every cm to find the pathological bone involvement. Sensitivity, specificity, and positive and negative predictive values of clinical and radiological findings were calculated. Specimens from 25 patients (49%) (4 segmental 21 hemi) demonstrated tumour invasion on histological examination. Clinical impression of mandibular invasion showed a sensitivity of 96% and specificity of 65%, whereas radiological examination had a sensitivity of 92% and specificity of 88%. When considered together, clinical and radiological examinations were able to detect all the cases of bone invasion, but specificity was only 58%. This study advocates careful correlation of clinical and radiological findings prior to definitive therapy, as clinical examination tends to over diagnose bone invasion in tumours adjacent to the mandible. The specificity of imaging was also found to be low pointing towards the need for more specific diagnostic tools in doubtful cases. Aggressive surgical therapy, namely segmental or hemi resection of mandible is warranted in case of tumours of the lower alveolus with definite bone invasion. In case of carcinomas of the buccal mucosa and tongue the mandibular resection can be limited to that required for clearance of margins provided the radiology is negative.     

口腔鳞癌患者下颌骨受侵的术前诊断和处理

目的：探讨临床检查、影像学检查（X线、CT、MRI）及术中探查诊断口腔鳞状细胞癌侵犯下颌骨及选择手术方式的价值。方法：对1993～2004年间49例口腔鳞状细胞癌行手术治疗的患者资料进行总结，将临床检查、影像学检查（X线、CT、MRI）及术中探查判断下颌骨受侵的结果与术后病理进行比较。利用SPSS13．0统计软件包比较上述方法在诊断下颌骨受侵及选择下颌骨手术方式上的价值。结果：临床检查诊断下颌骨受侵的敏感度为42．9％（9／211．特异度为100％（28／28），阳性预测值为100％（9／9），阴性预测值为70.0％（28，40），准确率为75.5％（37/49）；术中探查分别为：90．5％（19/21）、75．0％（21/28）、73．1％（19/26）、91.3％（21／23）和81．6％（40/49）；X线、CT、MRI的敏感度分别为100％（2/2）、83．3％（10／12）和40％（2/5）；特异度分别为100％（5／5）、100％（11／11）和100％（2／2）。下颌骨未受侵而行下颌骨切除者28例，其中帽状切除20例，骨段切除8例；而下颌骨受侵的21例患者中，行帽状切除3例，骨段切除18例。下颌骨手术方法对患者生存率的影响无显著性差异（P＞0．05）。结论：综合应用临床检查、下颌骨X线片、CT、MRI及术中探查能提高口腔癌下颌骨受侵诊断的准确率，为保留下颌骨的完整性提供比较可靠的依据。     

3种方式处理下颌骨对舌鳞癌患者手术预后的影响

目的：探讨舌癌病人下颌骨的不同处理方法与手术远期预后的关系,为舌癌患者的手术选择提供参考。方法：随访71例接受手术治疗的舌癌患者5年,分析术后影响预后因素,评价3种不同的下颌骨处理方式与患者预后的关系。结果：下颌骨处理方式对于舌鳞癌患者生存率有直接影响,其中未处理下颌骨患者5年总体生存率56.3%,边缘性去骨截骨患者的5年总体生存率为53.6%,而节段性截骨患者的仅为51.7%。结论：舌癌的预后不完全由下颌骨的切除方式决定的,而是由其侵袭性决定的,因此对于舌癌患者要根据不同情况选择不同方式处理下颌骨,在提高患者生存率的情况下,尽量保存下颌骨的完整性。     

Zur Indikation und Morbidität der Kontinuitätsresektion des Unterkiefers beim Plattenepithelkarzinom der unteren Mundhöhlenetage

Background

Segmental resection of the mandibula in oral cancer surgery leads to both functional and aesthetic problems. The decision to preserve or resect the mandible depends on the vicinity of the lesion to the bone. Consequently, based on the rules of safety margins to all planes that are recommended for soft tissues, each lesion that is closer than 10 mm to the mandible needs resection of the bone.

Patients and methods

To establish data-based treatment modalities, a retrospective study was initiated and the results from all preoperative staging investigations of 152 patients with intraoral squamous cell carcinoma who underwent continuity or marginal resection of the mandible were evaluated. The histological outcome of the resected bone was compared to the staging results. Functional rehabilitation and long-term follow-up including survival rates were evaluated. The study reports on typical complications following segmental resection such as fracture of the reconstruction plate and demonstrates experiences with secondary microsurgical reconstructive surgery.

Results

Mainly in cases of stage T1 and T2 carcinomas which are closer than 10 mm to the bone and clinically do not show any infiltration to the mandible, a marginal resection seems to be adequate. The decision about the extension of mandibular resection can be based on intraoperative cross sectional investigation of the periosteum. The survival rate of patients with intraoral carcinomas close to the mandible who underwent marginal mandibulectomy seems to be the same as in cases of continuity resection. A more conservative management of mandibular resection seems to be adequate and a data-based concept to standardize therapy of mandibular resection is presented.     

Influence of bone invasion and extent of mandibular resection on local control of cancers of the oral cavity and oropharynx

The aim of this paper was to evaluate the influence of bone invasion on treatment outcome among patients with cancers of the oral cavity and oropharynx and to determine whether or not outcome was influenced by the extent of mandibular resection. A review of 127 prospectively documented patients who were treated with marginal or segmental resection for oral (n = 110) and oropharyngeal (n = 17) cancers was undertaken. There were 97 males and 30 females with a median age of 61 years. Clinical T stages were: T1 17 patients, T2 33, T3 22, T4 55. Median followup was 4 years. A total of 94 patients underwent marginal resections and 33 underwent segmental resections. Histological bone invasion was present in 17 patients (16%) in the marginal resection group and 21 patients (64%) in the segmental group (P<0.05). Soft tissue surgical margins were positive in 11 patients (12%) in the marginal group and in seven patients (21%) in the segmental group (P=not significant). Local control did not correlate significantly with T stage, the extent of mandibular resection or the presence of histological bone invasion, but was significantly influenced by positive soft tissue margins (P<0.01). Among patients with bone invasion, the local control rate was higher following segmental resection when compared to marginal resections (87% vs 75%) but this was not statistically significant. Survival was significantly influenced by positive soft tissue margins but not bone invasion or the type of resection. We conclude that bone invasion alone did not predict for local control or survival rates among patients with oral and oropharyngeal cancers. Involved soft tissue margins were highly predictive of local recurrence and decreased survival. Conservative resection of the mandible is safe as long as marginal mandibulectomy does not lead to compromise of soft tissue margins. Segmental resection should be reserved for patients extensive bone invasion or those with limited invasion in a thin atrophic mandible.     

Mandibular invasion of lower gingival carcinoma in the molar region: its clinical implications on the surgical management

The spread pattern of a tumour and its extent in the mandible are important in the management of gingival cancer. Sixteen patients with gingival squamous cell carcinoma (SCC) involving the mandible in the molar region were included in this study. Resection specimens of the mandibular bone and adjacent cancer were histologically analysed to identify the type and characteristics of invasion and were compared with the radiological features. Our results showed that the actual width of invasion was underestimated to a greater extent than the actual depth of invasion. For horizontal aspects, four dentate cases had horizontal intramedullary spread underneath intact mucosa or cortical bone extended from the main foci of tumour that infiltrated through the occlusal surface. For vertical aspects, nerve invasion took place in only one of 16 specimens, while five cases showed downward infiltration beyond the inferior alveolar canal without nerve involvement, so that the pattern of tumour spread was mostly transmedullary rather than perineural in previously non-irradiated cases. These cases with deep infiltration showed the infiltrative type of invasion in the dentate mandible. And when the tumour was related with previous dental extractions or curettage, it tended to be more extensive than what was predicted from an imaging point of view. These pathological and clinical features affecting the tumour spread should be considered in the management of gingival SCC in the molar region.     

Lateral segmental mandibulectomy reconstruction with bridging reconstruction plate and anterolateral thigh free flap: a case series of 30 consecutive patients

Lateral posterior segmental mandibular defects present a reconstructive challenge and an osseous flap would be the gold standard to reconstruct such a defect. However, combining a mandibular reconstruction plate (MRP) with a soft-tissue free flap (to restore mucosal integrity and provide durable coverage of the plate itself) offers an alternative option for posterior segmental mandibular defects in patients who are not suitable for osseous reconstruction, or do not choose it. We retrospectively reviewed 30 consecutive patients (19 male and 11 female) who underwent reconstruction of a segmental mandibulectomy defect using a bridging MRP and anterolateral thigh (ALT) free flap. The mean (range) age was 67 (31-87) years. The American Society of Anesthesiologists’ (ASA) status of the study population comprised Grade 1 (n = 10), Grade 2 (n = 18), and Grade 3 (n = 2). The majority of patients had oral cavity squamous cell carcinoma (n = 26) involving the mandible, two had osteoradionecrosis, and two mucoepidermoid carcinoma. Four patients had complications specific to the reconstruction, and flap loss occurred in one (96.7% success rate). Metalwork infection occurred in three, including one plate extrusion and one plate fracture. The median length of stay was 10 days, and mean (range) duration of follow up 23.3 (1-96) months. This technique is an alternative reconstructive option for the non-tooth-bearing mandible. Reconstructing a posterolateral segmental mandibulectomy defect with a bridging MRP and ALT free flap offers a robust reconstructive alternative with a favourable complication profile.     

基于micro-CT的下颌牙龈癌颌骨侵犯的影像学评估及分析

目的： 对下颌牙龈癌颌骨侵犯进行影像学评估及分析,为进一步优化手术方案及术后治疗提供影像学依据。方法： 选择60例下颌牙龈癌手术患者,分析术前曲面体层片、平扫和增强CT,并对其中符合条件的30例手术标本进行micro-CT三维重建,分析骨密度、骨小梁厚度、骨小梁分离度等相关参数。采用SPSS 22.0软件包对数据进行统计学分析。结果： 常规影像学检查,曲面体层片、平扫及增强CT均有不足,micro-CT三维重建可以准确区分骨松质及骨皮质,评估下颌骨侵犯的范围及程度,相应的数据参数分析癌边缘及癌中心与正常下颌骨组织的皮质骨骨密度显著降低（P<0.05）,骨小梁厚度显著变薄（P<0.05）,松质骨骨密度显著降低（P<0.05）。癌中心与正常下颌骨组织骨小梁分离度增加（P<0.05）。结论： 目前对于下颌牙龈癌的手术方案还存在争议,进一步提高CT检查精度,可能会为制定下颌牙龈癌手术方案提供更精确的指导。     

Marginal resection for carcinoma of the mandibular alveolus and gingiva where radiologically detected bone defects do not extend beyond the mandibular canal.

PURPOSE: The study goal was to investigate the adequacy of marginal resection of the mandibular bone in cases of squamous cell carcinomas of the lower alveolus and gingiva where the radiologically detected bone defect does not extend beyond the mandibular canal. PATIENTS AND METHODS: Sixty-two patients who have had a mandibulectomy performed with or without preoperative radiotherapy and chemotherapy were the study subjects. This retrospective study investigated the correlation between the preoperative radiographic appearance and histopathologic findings of the excised tissue. The results of the treatments were evaluated. RESULTS: In the cases with erosive bone defects, the extent of the bone involvement did not exceed the extent of the radiographically detected bone defects. However, in 7 (36.8%) of the cases with moth-eaten type bone defects, the extent of bone involvement exceeded the bone defects detected by radiography. Further, 10 of the 16 cases with no apparent bone defect showed apparent bone involvement by the tumors histologically. There were no differences in the 5-year cumulative survival rate between the marginal resection and segmental groups. CONCLUSIONS: Marginal resection was effective in controlling mandibular alveolus and gingival cancers when radiologically detected erosive bone defects did not extend beyond the mandibular canal. Marginal resection was inadequate when moth-eaten defects were radiologically detected, except when the bone defects were confined to the alveolar bone.     

Assessment of mandibular invasion of squamous cell carcinoma by various modes of imaging: constructing a diagnostic algorithm

The aim of this study was to determine the optimal combination of preoperative examination methods to predict mandibular invasion by squamous cell carcinoma of the oral cavity. Data were gathered prospectively but evaluated retrospectively. The preoperative results of clinical examination, conventional radiography, bone single photon emission computed tomography (SPECT), computed tomography and magnetic resonance imaging were compared to the histological results of resection specimens from 67 patients with tumours, adjacent or fixed to the mandible, histologically confirmed as squamous cell carcinoma. The examination methods with acceptable sensitivity and specificity were selected and diagnostic algorithms were constructed using all possible combinations. The preferred diagnostic algorithm was found to be either computed tomography or magnetic resonance imaging, followed by a bone SPECT in cases where the first scan is negative. A negative bone SPECT rules out mandibular invasion (100% sensitivity). This algorithm accurately predicted mandibular invasion in 85% of the patients, without yielding false negative results. In this study group, application of such an algorithm would have resulted in a reduction of the number of unnecessary mandibular resections by 50%. The suggested, preferred, diagnostic algorithm shortens the preoperative screening process, avoiding unnecessary costs, as well as considerably reducing the number of unnecessary mandibular resections.     

Autoradiographic evaluation of 99mTc-methylene diphosphonate accumulation in oral cancer invading the mandible.

PURPOSE: Skeletal scintigraphy, a sensitive diagnostic tool used to detect changes in bone, is helpful for evaluating bone invasion by oral cancer. However, the exact sites of accumulation of 99mTc-phosphate compounds in the mandible have not yet been fully elucidated. The aim of this study was to determine the localization of 99mTc-methylene diphosphonate (MDP) in the areas of mandible that have been invaded by cancer. PATIENTS AND METHODS: Seven patients with oral cancer (lower gingiva, 4; tongue, 2; floor of the mouth, 1) who underwent surgical treatment with mandibular bone resection were included in the study. Autoradiography and contact macroradiography were used for evaluation of 99mTc-MDP accumulation. RESULTS: Radioactivity reflecting accumulation of 99mTc-MDP was documented encircling the portion of the mandible with cancerous invasion, suggesting that 99mTc-MDP accumulated in immature bone. High uptake also was found in the periosteal reactive bone around the cortical bone. CONCLUSIONS: The amount of increased 99mTc-MDP circumscribing carcinoma invasion varies among cases. Additionally, uptake may not correspond directly with the amount of the carcinoma invasion; that seen in periosteal bone could be attributed mistakenly to bone invasion in planar scintigraphy.     

Can radiological examination of mandibular bone invasion accurately predict the need for mandibular resection in oral squamous cell carcinoma?

Bone invasion by oral squamous cell carcinoma necessitates jaw resection, with preoperative imaging ideally able to guide the resection. A retrospective review of 109 patients with oral squamous cell carcinoma who underwent mandibular resection was performed. Eighty-three had preoperative computed tomography (CT) imaging and 72 underwent magnetic resonance imaging (MRI). The presence of bone invasion on imaging was compared to histopathology. Bone invasion was detected in 44 of 109 resection specimens (40.4%) and was identified on CT in 31 of 83 cases (37.4%) and on MRI in 35 of 72 cases (48.6%). The sensitivity and specificity of CT for detecting bone invasion was 69.0% and 79.6%, respectively, while for MRI was 87.1% and 80.5%, respectively. Histological detection of bone invasion was associated with greater disease-specific mortality (P = 0.002), as was MRI detection of bone invasion (P = 0.027). CT detection was not significant (P = 0.240). Negative prediction of bone invasion was 95% accurate for both modalities in clinically non-invaded mandibles. Survival was reduced in patients who underwent marginal mandibular resection when bone invasion was detected histologically (33.3% vs. 70.5%, P = 0.277) and with CT, although this was not statistically significant. More data are required to determine whether more aggressive resection is warranted when bone invasion is detected preoperatively.     

Use of intraoperative cytologic assessment of mandibular marrow scrapings to predict resection margin status in patients with squamous cell carcinoma.

PURPOSE: This study assessed the feasibility of intraoperative microscopic assessment of mandibular bone resection margins in patients undergoing segmental resection of mandible for treatment of squamous cell carcinoma. PATIENTS AND METHODS: This prospective pilot study involved 7 consecutive patients undergoing segmental resection of mandible as part of surgical treatment of oral squamous cell carcinoma. Cytologic examination of smear/touch preparations of 35 bone marrow scrapings, including simulated positive margins, was performed. RESULTS: "Malignant" excision margins produced a high cell yield, and it was easy to assign samples to malignant or benign categories on microscopic examination. All the simulated positive margins were easily identified. No false positive results were found. CONCLUSION: Cytologic examination of bone excision margin scrapings is a rapid, inexpensive, and accurate technique. This study confirms its feasibility and accuracy in cases of mandibular resection for squamous cell carcinoma.     

A study of osteoclast-related cytokines in mandibular invasion by squamous cell carcinoma

The purpose of this study was to analyze the mechanism of bone invasion in carcinoma of the mandibular gingiva. We investigated 38 specimens of lower gingival carcinoma and histopathologically classified them into an invasion group (23 cases) and a non-invasion group (15 cases) on the basis of light microscopy evidence. These specimens were examined using immunohistochemical techniques involving antibodies of parathyroid hormone-related protein (PTHrP), tumor necrosis factor (TNF)-alpha, interleukin (IL)-1alpha, -1beta, -6, -11, -18 and transforming growth factor (TGF)-beta. The invasion group showed a high level of expression of PTHrP, TNF-alpha, IL-6 and IL-11 positive cells (P<0.01 versus non-invasion group). The difference in the levels of expression of IL-1alpha, -1beta, -18 and TGF-beta positive cells was not significant between these two groups. Our results suggest that various cancer-derived cytokines, such as PTHrP, TNF-alpha, IL-6 and IL-11, play an important role in the mechanism of bone invasion associated with lower gingival squamous cell carcinoma.     

Computer-aided 3-D 99mTc-DPD-SPECT reconstruction to assess mandibular invasion by intraoral squamous cell carcinoma: diagnostic improvement or not?

OBJECTIVE: A prospective study was designed to compare computer-aided 3-D 99mTc-DPD-SPECT (Technetium-Dicarboxy propan-single photon emission CT) reconstruction with clinical examination, panoramic radiography, CT scan and conventional 99mTc-DPD-SPECT investigation in the assessment of mandibular bone invasion by squamous cell carcinoma. PATIENTS AND METHODS: Between October 1997 and December 1999, 88 patients with intraoral squamous cell carcinoma of the regions adjacent to the mandible were enrolled in this study. In 50 cases, mandibular resection (segmental or marginal) was performed based on the pre-treatment diagnostic results. Imaging studies were read independently by four experienced observers. RESULTS: No differences could be found between presurgical 3-D 99mTc-DPD-SPECT reconstruction and conventional 99mTc-DPD-SPECT investigation. Both techniques revealed a sensitivity of 100% whereas CT scan showed the greatest specificity (93.8%). SPECT investigation had a specificity of 91.6% and the greatest efficiency (95.4%). The greatest predictive positive value was found for CT scan (92.3%). Clinical examination and panoramic radiography displayed the lowest sensitivity, 82.5% vs. 85.0%, and specificity, 79.2% vs. 89.5% respectively. CONCLUSION: This investigation does not provide evidence that 3-D 99mTc-DPD-SPECT reconstruction has any advantages when compared to conventional 99mTc-DPD-ECT investigation in the assessment of mandibular invasion by squamous cell carcinoma. Despite a sensitivity of 100% the specificity is still in need of improvement. Until newer methods or techniques become available the combination of CT scanning and conventional 99mTc-DPD-SPECT investigation appears to be the best means of detecting tumour invasion preoperatively and is thus helpful in directing appropriate surgical procedure.     

下颌骨切除骨缺损修复术后的X线影像分析

目的 :观察下颌骨切除骨缺损修复术后X线影像特点。方法 :对下颌骨良性肿瘤切除骨缺损修复术后的42例病例的X线影像分析。结果 :骨性愈合 31例 ;植入骨吸收 5例 ;植入块断裂 6例。结论 :曲面断层和下颌骨侧位应作为术后必备的片位 ;术后 1～ 2周、3～ 6月、1年以后作为随访的三个阶段 ,能较准确地观察术后愈合情况     

Computer-aided 3-DTc-DPD-SPECT reconstruction to assess mandibular invasion by intraoral squamous cell carcinoma: diagnostic improvement or not?

Objective: A prospective study was designed to compare computer-aided 3-D^99mTc-DPD-SPECT (Technetium-Dicarboxy propan-single photon emission CT) reconstruction with clinical examination, panoramic radiography, CT scan and conventional^99mTc-DPD-SPECT investigation in the assessment of mandibular bone invasion by squamous cell carcinoma. Patients and Methods: Between October 1997 and December 1999, 88 patients with intraoral squamous cell carcinoma of the regions adjacent to the mandible were enrolled in this study. In 50 cases, mandibular resection (segmental or marginal) was performed based on the pre-treatment diagnostic results. Imaging studies were read independently by four experienced observers. Results: No differences could be found between presurgical 3-D^99mTc-DPD-SPECT reconstruction and conventional^99mTc-DPD-SPECT investigation. Both techniques revealed a sensitivity of 100% whereas CT scan showed the greatest specificity (93.8%). SPECT investigation had a specificity of 91.6% and the greatest efficiency (95.4%). The greatest predictive positive value was found for CT scan (92.3%). Clinical examination and panoramic radiography displayed the lowest sensitivity, 82.5% vs. 85.0%, and specificity, 79.2% vs. 89.5% respectively. Conclusion: This investigation does not provide evidence that 3-D^99mTc-DPD-SPECT reconstruction has any advantages when compared to conventional^99mTc-DPD-ECT investigation in the assessment of mandibular invasion by squamous cell carcinoma. Despite a sensitivity of 100% the specificity is still in need of improvement. Until newer methods or techniques become available the combination of CT scanning and conventional^99mTc-DPD-SPECT investigation appears to be the best means of detecting tumour invasion preoperatively and is thus helpful in directing appropriate surgical procedure.     

虚拟手术计划在经口内入路行下颌骨切除及精确重建中的应用：附9例报道

目的 介绍在虚拟手术计划辅助下行经口内入路下颌骨切除和血管化骨重建的经验,评价术后重建效果。方法 对9例下颌骨良性肿瘤患者术前行虚拟手术计划,设计、制作适用于口内操作的预设钉孔的导板。然后经口内入路利用截骨导板行下颌骨切除,预弯钛板及血管化骨瓣的植入和固定。术中实时导航验证新下颌骨的空间位置。术后半年,通过临床及影像学检查评价患者外形和功能;通过术后CT与术前STL模型拟合,评估下颌骨重建的精确性。采用SPSS 15.0软件包对数据进行统计学分析。结果 在虚拟手术计划辅助下,9例患者均顺利完成经口内入路下颌骨切除及血管化下颌骨重建,术中导航证实重建下颌骨位置准确。术后半年复查见患者面部对称,无面瘫及开口受限。患者对手术效果满意。图像拟合显示,截骨线位置精确,误差<1 mm[（0.72±0.15）mm],下颌骨重建位置与术前设计高度一致,误差为（1.76±1.99）mm。结论 在虚拟手术计划辅助下,利用预设钉孔的导板和预弯钛板,可以精确实施口内下颌骨切除及血管化骨重建,避免了口外切口,显著提高了下颌骨重建的精确性。