Symmetrical Midfacial Growth After Pediatric Mandibular Reconstruction With Free Fibula Flap.

BACKGROUND: Free fibula is the workhorse flap for mandibular reconstruction and is increasingly being used in pediatric patients. However, craniomaxillofacial growth and development involve interdependent processes, and it remains unknown whether mandibular reconstruction with free fibula allows symmetric growth of the midface. PURPOSE: The study evaluated midfacial symmetry after pediatric mandibular defect reconstruction. STUDY DESIGN, SETTING, SAMPLE: This retrospective cohort study included pediatric patients aged ≤14 years who underwent mandibular reconstruction with free fibula flap. Postoperative computed tomography data were obtained at predefined follow-up time points. Midfacial symmetry was evaluated based on 3-dimensional (3D) cephalometry. PREDICTOR VARIABLE: The predictor variable was the side of the midface (affected or healthy side relative to the mandibular defect). MAIN OUTCOME VARIABLES: The primary outcome variable was postoperative midfacial symmetry (at 1 week, 6 months, 1 year, 2 years, and >3 years, or after the age of 18 years), assessed in horizontal, vertical, and anteroposterior dimensions using 3D cephalometry. Another outcome variable was patient satisfaction based on a self-evaluation using visual analog scoring. COVARIATES: Sex, age, diagnosis, and type of denture restoration. ANALYSES: Paired t tests were performed to assess the relationship between the predictor and outcome variables, with the significance level of P < .05. RESULTS: A total of 13 patients were included in this study (9 males and 4 females; mean age: 12.23 ± 2.39 years). The average distance from upper first molar point (U6) to the horizontal plane on the affected side became greater than on the healthy side (difference: 0.7 ± 0.5 mm to 1.6 ± 1.4 mm, P < .05), while the average distance from pterygomaxillary fissure to coronal plane on affected side became shorter than that on the healthy side (difference: 0.6 ± 0.6 mm to 1.2 ± 1.1 mm, P < .05) from 1 year after the surgery. There were no statistically significant differences in the remaining measurements between the 2 sides (P > .05). All the patients were satisfied with their postoperative facial symmetry. CONCLUSIONS AND RELEVANCE: There were no severe midface deformities after pediatric mandibular reconstruction with free fibula flap. Meanwhile, pediatric mandibular reconstruction and proper occlusion could promote midfacial growth and symmetry.

Vascularized Free Fibular Flap in Oral and Maxillofacial Reconstruction: A 20-year Experience at a Single Institution Using 2640 Flaps.

BACKGROUND: This retrospective study reviewed all patients who underwent oral and maxillofacial reconstruction with fibular flaps in the last 2 decades at a single hospital. MATERIALS AND METHODS: We reviewed all patients with fibular flaps from 1999 to 2018. The following data were collected: sex; age; reconstruction region; diagnosis; the number of days spent in the hospital after surgery; time spent using a tourniquet for harvesting a fibula flap; vessels at the recipient site; the prevalence of unplanned reoperations; the prevalence of flap failure; history of preoperative radiotherapy; virtual surgical planning; segments of the fibula. RESULTS: In total, 2640 patients were included. The mean age was 45.5 years. The most prevalent region of reconstruction was the mandible (n=2347, 88.9%). The most common diagnosis was squamous cell carcinoma (n=1057, 40.0%). The mean number of days spent in the hospital after surgery decreased year-by-year from 18.3 days to 10.4 days. The first choice of recipient artery was the facial artery (n=1643, 62.2%) and that of the recipient vein was the external jugular vein (n=1196, 45.3%). The prevalence of surgical success was 97.6%. Prevalence of unplanned reoperations was 7.5%. CONCLUSIONS: The fibular flap was a good choice for oral and maxillofacial bony reconstruction in most cases.

Reconstruction of Complete Bilateral Maxillary Defects With Free Flaps.

ABSTRACT: Reconstruction of complete bilateral maxillary defects (CBMDs) can be challenging due to the extensive loss of bone and soft tissues. This is a retrospective case series of 46 consecutive patients with CBMDs that were reconstructed with different micro-vascular free flaps. The authors aimed to evaluate the surgical outcomes and discuss the different reconstruction options in this case series. Thirty-six patients underwent reconstruction following ablation surgery for malignant tumors, 6 for benign tumors, 3 patients were treated for osteomyelitis, and 1 patient underwent free flap reconstruction for posttraumatic defects. Free fibula flap (n = 26) is the most commonly used reconstruction method in this case series, which was used in all defect types. This is followed by anterolateral thigh flap (n = 10), 5 rectus abdominis myocutaneous free flap, 3 radial forearm free flaps, and 2 composite free flaps. In this series, 44 free flaps survived, whereas only 2 flaps were lost. All patients could resume a soft diet postoperatively. Reconstruction of CBMDs with vascularized free flaps is a safe and reliable procedure.

Outcomes of Zygomatic Complex Reconstruction With Patient-Specific Titanium Mesh Using Computer-Assisted Techniques.

PURPOSE: Zygomatic complex defects after extensive maxillectomy can cause severe esthetic and functional deformities. Patient-specific titanium mesh fabricated using a computer-assisted technique is a promising method for such midface reconstruction. The aim of this study was to evaluate the application and clinical outcomes of this technique. PATIENTS AND METHODS: This was a retrospective study that included 9 patients with zygomatic complex defects after extensive maxillectomy from 2015 through 2017 at the authors' institution. A 3-dimensional stereo model was obtained based on mirror images of the unaffected side to fabricate a patient-specific titanium mesh using computer-assisted design and manufacturing. Titanium mesh was used to restore the contour of the zygomatic complex with free flap reconstruction after tumor resection. Anterolateral thigh flaps were used in 8 cases and a myocutaneous fibula flap was used in 1 case. Symmetry of the zygomatic complex was evaluated by measuring the zygomatic eminence on the postoperative computed tomogram, and complications were recorded during follow-up visits. Facial symmetry was self-evaluated and scored. RESULTS: Mean duration for follow-up was 27.3 months (range, 15 to 39 months). Mean deviation of the zygomatic eminence between the reconstructed and unaffected sides was 1.4 ± 0.5 mm. No significant difference was noted in the zygomatic eminence between the reconstructed and unaffected sides (P = .591). Titanium mesh exposure occurred in only 1 patient after radiotherapy. There were no other remarkable complications. All patients were satisfied with their postoperative facial symmetry. CONCLUSION: Patient-specific titanium mesh fabricated using a computer-assisted technique was an alternative option for extensive zygomatic complex reconstruction, resulting in acceptable clinical outcomes. A study with a larger sample and long-term follow-up is needed for the observation of long-term outcomes and risk of titanium mesh-related complications.

The Use of Submental Island Flap for Total Lower Lip Reconstruction: A Case Report.

Total lower lip reconstruction was performed in a 72-year-old man following a squamous cell carcinoma resection. To obtain an optimal functional result and to avoid any additional facial scarring, a submental island flap was used in a one-stage procedure. After 2.5 years of follow-up, the patient is very satisfied with the shape and function of the lower lip.

[Clinical features of osteonecrosis of jaws after bisphosphonates therapy for bone metastasis of breast cancer].

OBJECTIVE: To understand the clinical features of osteonecrosis of the jaw after bisphosphonates use for therapy of breast cancer patients with bone metastasis. METHODS: The cases diagnosed as bisphosphonates-related osteonecrosis of the jaws (BRONJ) were retrospectively analyzed from January 2011 to August 2015 in the Peking University School and Hospital of Stomatology, and those breast cancer patients with bone metastasis were selected. The clinical symptoms, imaging characteristics and treatment results were summarized. RESULTS: A total of 14 cases of breast cancer patients with bone metastasis were selected, with an average age of 60.21 years. The average time of suffering from breast cancer was 9.77 years, and the average time of bone metastasis and bisphosphonates drugs use was 5.67 and 3.29 years individually. There was no patient with systemic application history of hormone therapy, and no history of diabetes. There were 9 patients with tooth extractions history, and the mean time of bone necrosis symptoms was 8.58 months. There were 10 cases with bone necrosis occurring on mandible, 3 cases on maxilla, and one case with both upper and lower jaws involved. Among the 10 patients with surgical treatment, there were 3 cases cured, and 6 cases improved. However, the clinical symptoms of 2 cases with conservative treatment were significantly aggravated. CONCLUSION: The medication time between the bisphosphonates use beginning and the occurrence of BRONJ is relatively long. The history of diabetes and long-time hormone use did not exist in this group. Tooth extraction itself does not determine the severity of BRONJ. Mandible is the most common site involved by BRONJ. Surgical treatment can alleviate the clinical symptoms of BRONJ with breast cancer to some extent.

Outcomes of Orbital Floor Reconstruction After Extensive Maxillectomy Using the Computer-Assisted Fabricated Individual Titanium Mesh Technique.

PURPOSE: Orbital floor defects after extensive maxillectomy can cause severe esthetic and functional deformities. Orbital floor reconstruction using the computer-assisted fabricated individual titanium mesh technique is a promising method. This study evaluated the application and clinical outcomes of this technique. PATIENTS AND METHODS: This retrospective study included 10 patients with orbital floor defects after maxillectomy performed from 2012 through 2014. A 3-dimensional individual stereo model based on mirror images of the unaffected orbit was obtained to fabricate an anatomically adapted titanium mesh using computer-assisted design and manufacturing. The titanium mesh was inserted into the defect using computer navigation. The postoperative globe projection and orbital volume were measured and the incidence of postoperative complications was evaluated. RESULTS: The average postoperative globe projection was 15.91 ± 1.80 mm on the affected side and 16.24 ± 2.24 mm on the unaffected side (P = .505), and the average postoperative orbital volume was 26.01 ± 1.28 and 25.57 ± 1.89 mL, respectively (P = .312). The mean mesh depth was 25.11 ± 2.13 mm. The mean follow-up period was 23.4 ± 7.7 months (12 to 34 months). Of the 10 patients, 9 did not develop diplopia or a decrease in visual acuity and ocular motility. Titanium mesh exposure was not observed in any patient. All patients were satisfied with their postoperative facial symmetry. CONCLUSION: Orbital floor reconstruction after extensive maxillectomy with an individual titanium mesh fabricated using computer-assisted techniques can preserve globe projection and orbital volume, resulting in successful clinical outcomes.

[Classification and reconstruction of 1,107 cases of maxillary defects].

OBJECTIVE: To investigate the defect types and reconstruction methods of maxillary defects. METHODS: The database of 1,107 cases with maxillary defects in Peking University School and Hospital of Stomatology from January 1985 to December 2010 was established. There construction methods were reviewed. The defect types were classified according to Brown classification system. RESULTS: In the 1,107 cases, 1,104 cases could be classified according to Brown classification system. The most common type was 2a with 559 cases (50.6%). Among all the 1,107 cases, 349 cases were reconstructed with autotransplantation, 443 cases with prosthesis, 107 cases untreated, and 208 patients lost to the follow-up. There was a significant growing trend over time for the application of free flaps and a downward trend of prosthesis. The most popular free flaps were fibular flap (88 cases) and radial forearm flap (75 cases). Rectus abdominis flap and anterolatreal thigh flap were fit for extensive maxillary defects. CONCLUSION: The most common defect type is 2a. Free flap has become the dominant option for maxillary reconstruction. Free flaps could be selected according to the maxillary defect types.

Long-Term Outcomes after Pediatric Mandibular Reconstruction Using Vascularized Free Fibula Flap.

BACKGROUND: The purpose of this study was to evaluate the long-term outcomes of mandibular reconstruction with vascularized free fibula flap in pediatric patients. METHODS: Consecutive cases of mandibular reconstruction with vascularized free fibula flaps in pediatric patients at Peking University School and Hospital of Stomatology between 1999 and 2019 were reviewed. Postoperative computed tomography (CT) data of all patients were collected at each postoperative follow-up point, and after the age of 18 years. The length and height of the grafted fibula and the length of the remaining mandible were evaluated by measuring the three-dimensional CT data using ProPlan CMF 3.0 software. Lower limb function was evaluated using the Enneking evaluation scale. Facial symmetry was self-evaluated and scored. Statistical analysis was performed on the data obtained. RESULTS: Fourteen patients were included in this study. All flaps were successful. The CT measurement results showed growth in the length of the grafted fibula that reconstructed the mandibular ramus and the residual mandible ( P < 0.05). The height of the grafted fibula remained stable ( P > 0.05). Eight patients were followed up until they were older than 18 years, and the CT measurement results after 18 years showed an essentially symmetric mandible profile ( P > 0.05). All patients were satisfied with their postoperative facial symmetry. Enneking evaluation scores showed good recovery of lower limb functions. CONCLUSIONS: The vascularized free fibula flap for mandibular reconstruction in pediatric patients is safe and reliable. It also provides good cosmetic and functional outcomes, as it demonstrated positive growth. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Three-dimensional attachment morphometry and volumetric changes of masticatory muscles after free fibular flap reconstruction of the mandibular condyle.

This retrospective case-series study aimed to elucidate the three-dimensional attachment morphometric features and to quantify the volumetric changes of the masticatory muscles following free fibular flap reconstruction of the mandibular condyle. Navigation software (iPlan, version 3.0; Brainlab) was used to perform delineation and volumetric measurement of the masticatory muscles using DICOM data. In total, 30 patients were included in this retrospective case series. In 25 cases (83.33%), the lateral pterygoid muscle achieved reattachment within 6 months postoperatively. The medial pterygoid muscles on the affected side achieved ectopic attachment in all cases. However, masseter reattachment on the affected side was achieved in only three cases. On the normal side, the volumes of lateral pterygoid muscle, medial pterygoid muscle, and masseter had recovered to almost preoperative levels at 1 year postoperatively. On the affected side, the volume of medial pterygoid muscle had decreased significantly (p = 2.4e-04) at 3 months postoperatively. The volumes of lateral pterygoid muscle and masseter showed mild decreases at 3 months postoperatively, but these were not significant (p = 0.52 and p = 0.05 for the pterygoid muscle and masseter, respectively). At 6 months after surgery, with the exception of the volume of the lateral pterygoid muscle (p = 0.06), the total volume of the masticatory muscles decreased significantly on the affected side. The volumes of lateral pterygoid muscle, medial pterygoid muscle, and masseter showed significant decreases at 1 year postoperatively (p = 0.03, p = 4.7e-08, and p = 1.1e-05, respectively) on the affected side. The postoperative volumes of the masseter, medial pterygoid, and lateral pterygoid muscles showed significant decreases due to the loss of reattachment. The results of this study may not help to ascertain whether reattachment of masticatory muscles will lead to better function. As a consequence, clinical trials of higher quality are needed.

Quality of life in patients with cancer-related Brown IIb maxillary defect: A comparison between conventional obturation rehabilitation and submental flap reconstruction.

OBJECTIVES: The purpose of this retrospective study was to compare the differences in quality of life (QOL) outcomes between the conventional obturator prostheses (COP) and the pedicled submental artery island flap (SAIF) in the reconstruction of Brown IIb maxillary defects. MATERIALS AND METHODS: The QOL of 116 eligible patients who had a lapse ≥ 12 months after the cancer-related maxilla ablation was evaluated by the University of Washington quality of life scale (UW-QOL), Performance Status Scale for Head and Neck (PSS-HN), and Obturator Functioning Scale (OFS). RESULTS: Patients in the SAIF group reported statistically and clinically significant higher overall QOL scores but lower chewing scores in the UW-QOL scale when compared with those in the COP group (P < 0.05). Clinically significantly higher scores were also observed in the recreation and anxiety domains in the UW-QOL scale for the SAIF group, but there was no statistical significances. The COP group reported more complaints about the nasal leakage when swallowing and the shape of the upper lip, and had a stronger willingness to avoid family or social events in the OFS (P < 0.05). CONCLUSIONS: For patients with Brown IIb defects, SAIF reconstruction can achieve reduced nasal leakage when swallowing, improved upper-lip contour, increased social activity, and superior overall QOL than COP. The inferior chewing function in the SAIF group indicated the need for dental rehabilitation with a conventional denture or osseointegrated implants.

Microanatomic study of the vascular and duct system of the submandibular gland.

PURPOSE: Autologous microvascular submandibular gland (SMG) transfer is an effective treatment for severe keratoconjunctivitis sicca (KCS). However, epiphora (excessive tear secretion) may occur after the successful transfer of whole submandibular gland because tear secretion level is closely related to the size of the transferred gland. The aim of this study was to investigate the microanatomy of SMG to explore the possibility of partial SMG transfer to prevent postoperative epiphora. MATERIALS AND METHODS: Sixty intact and histologically normal human SMGs from patients with benign tumor of the mandible who underwent vascularized mandibular reconstruction and removal of the SMG for anastomosis of the blood vessels were included in the study. SMGs were perfused with methacrylate to form resin casts of blood vessels and ducts. The length and diameter of the blood vessels and ducts in the casts were measured using a sliding caliper. The numbers of lobules, distribution of arteries, veins, and ducts, as well as the relationship among them, were analyzed. RESULTS: The resin cast of the gland showed a treelike structure, with the vessels gradually dividing into multiple branches. The arteries, veins, and ducts run in parallel and were roughly divided into 3 levels: from the stem extending into the main branches (level I), into the narrower secondary branches (level II), and then the secondary branches subsequently divided into terminal branches (level III). The structures of the blood vessels and ducts were similar at each level in the lobules. In the vein casts, communicating vessels were found between the anterior facial vein and the concomitant vein of the facial artery. CONCLUSION: The characteristic treelike structure of the SMG vascular and ductal system may provide useful information for partial gland transfers.

[Functional maxillary reconstruction with free composite fibula flap].

Maxillary defects resulting from tumor resection or trauma can cause severe functional and cosmetic deformities. Maxillary reconstruction has long been a challenge for oral maxillofacial surgeons. Functional maxillary reconstruction with vascularized composite bone flap and osseointegrated implants is one of the most important improvements in head and neck reconstructive surgery. Since 1999, our research group has performed a comprehensive research on functional maxillary reconstruction with free composite fibula flap. Clinical data of the patients with maxillary reconstruction using free fibula flap were analyzed to describe the indications and principles of perioperative period of this technique. The modified free fibula flexor-hallucis longus myofascial flap was introduced, which could overcome the disadvantages of traditional free composite fibula flap. The donor site morbidity, post-operative speech outcome, mastication function, and quality of life were evaluated objectively. The biomechanical effects of stress distribution on maxilla reconstructed by free fibula composite flap were analyzed by three-dimensional finite element analysis. These studies demonstrated maxillary defects can be reconstructed successfully using free fibula flaps. This procedure also allows dental implant or conventional denture rehabilitation, which can improve the patient's appearance and oral function and enhance the overall quality of life. The fibula free flap transfer has a high success rate and low perioperative complication rate, making it an ideal choice for maxillary defect reconstruction.

Long-term Effect of Individualized Titanium Mesh in Orbital Floor Reconstruction After Maxillectomy.

OBJECTIVE: The aim of this study was to determine the clinical outcomes and long-term stability of individualized titanium mesh combined with free flap for orbital floor reconstruction after maxillectomy and to identify the risk factors for titanium mesh exposure. MATERIAL AND METHODS: The data of 66 patients who underwent maxillectomy and orbital floor defect reconstruction by individualized titanium mesh in Peking University School and Hospital of Stomatology between 2011 and 2019 were retrospectively reviewed. Postoperative ophthalmic function and success of aesthetic restoration were assessed. Titanium mesh exposure was recorded and the risk factors were identified. RESULTS: Mean follow-up was for 24.8 months (range, 6-92 months). Ophthalmic function was successfully restored in 63/66 patients. Aesthetic restoration was not considered satisfactory by 10 patients. Titanium mesh exposure occurred in six patients (exposure rate, 9.1%). Preoperative radiotherapy was identified as an independent risk factor for mesh exposure (OR = 28.8, P = 0.006). Previous surgery, postoperative radiotherapy, pathological type of the primary lesion, the type of tissue flap applied, and the use of intraoperative navigation were not significant risk factors. Six patients with titanium mesh exposure underwent second surgery, but mesh exposure recurred in two patients due to insufficient soft tissue coverage. CONCLUSION: Individualized titanium mesh with free flap can effectively restore maxilla-orbital defects. Preoperative radiotherapy is an independent predictor of postoperative titanium mesh exposure. Adequate soft tissue coverage of the mesh may reduce the risk of mesh exposure. LEVEL OF EVIDENCE: 4 (case-control study) Laryngoscope, 131:2231-2237, 2021.

Clinical and anatomic study on the ducts of the submandibular and sublingual glands.

PURPOSE: To investigate the relationship between the ducts of the submandibular gland (SMG) and sublingual gland (SLG) and discuss its clinical application relating to SMG radiologic examinations and transfer. MATERIALS AND METHODS: The microanatomy of the SMG and SLG was investigated by use of 30 adult cadavers through anatomic dissection by use of a microscope. The relationship between the SMG and SLG ducts was observed and recorded during operations of microvascular autologous SMG transfer in 63 cases of severe keratoconjunctivitis sicca. RESULTS: There were 3 patterns of SLG and SMG duct anatomic variation: 1) The SMG and SLG have their own respective ducts that secrete separately at the orifices of the ducts in the floor of the mouth. 2) The SLG has a major duct that joins the duct of the SMG. 3) The SLG only has many fine ducts (7-15) that secrete in the floor of the mouth. CONCLUSIONS: The anatomy of the ducts of the SMG and SLG is quite complicated. More attention should be paid to the anatomy of the ducts during surgery or imaging procedures related to the SMG.

[Effect of autologous concentrated growth factor fibrin solution combined with Bio-Oss bone powder on mucosal healing and bone regeneration after oral implanted guided bone regeneration].

PURPOSE: To investigate the effect of autologous concentrated growth factor fibrin solution combined with Bio-Oss bone powder on mucosal healing and bone regeneration after oral implanted guided bone regeneration. METHODS: From October 2016 to December 2018, 83 patients with maxillary single anterior tooth loss and labial bone defect were treated, they were divided into two groups. Patients in the experimental group (42 cases) received autologous concentrated growth factor fibrin solution + Bio-Oss bone powder, while patients in the control group (41 cases) received Bio-Oss bone powder alone. The degree of mucosal healing, implant success, bone defect regeneration, pain and other complications were followed up 7 days, 6 weeks and 1 year after operation. The success rate and complications of the two groups were observed, as well as the differences of mucosal color, swelling degree, bleeding index, depth of probing, attachment loss, height of bone graft and thickness of bone formation were measured and recorded. Statistical analysis was performed using SPSS 25.0 software package. RESULTS: There was no significant difference in the success rate of implants between the two groups (95.24% vs 97.56%, P>0.05). The complication rate of the experimental group was significantly lower than that of the control group (2.38% vs 14.63%, P<0.05). The mucosal color and swelling degree scores of the experimental group were significantly lower than those of the control group [(0.65±0.03) points vs (2.01±0.15) points, (1.10±0.37) points vs (2.69±0.54) points, P<0.05], and the bleeding index, probing depth, and attachment loss were significantly lower than the control group [(0.35±0.05) vs (0.49±0.09), (3.39±0.62) mm vs (4.41±0.95) mm, (3.02±0.66) mm vs (5.31±0.91) mm, P<0.05], bone graft height and osteogenesis height were significantly higher than the control group [(2.61±0.50) mm vs (2.20±0.31) mm, (2.53±0.34) mm vs (2.02±0.27) mm, P<0.05]. The degree of postoperative pain in the experimental group was significantly lower than that in the control group(P<0.05). CONCLUSIONS: Rich self-concentrating growth factor fibrin solution combined with Bio-Oss bone powder can effectively promote mucosal healing and bone regeneration after oral implant-guided bone regeneration, and reduce postoperative pain and complications.

Applying computer techniques in maxillofacial reconstruction using a fibula flap: a messenger and an evaluation method.

While the application of computer-assisted maxillofacial surgery becomes increasingly popular, the translation from virtual models and surgical plans to actual bedside maneuvers and the evaluation of the repeatability of virtual planning remain to be major challenges. The objective of this study was to experiment the technique of using a resin template as a messenger in maxillofacial reconstruction involving a fibula flap. Another aim was to find a quantitative and objective method to evaluate the repeatability of preoperative planning. Seven patients who underwent maxillary or mandibular reconstruction were included in this study. The mean age was 25 years, and the mean follow-up period was 18.7 months. Virtual planning was carried out before surgery. A resin template was made according to the virtual design of bone graft through rapid prototyping technique and served as a guide when surgeons shaped the fibula flap during surgery. The repeatability of the virtual plan was evaluated based on the matching percentage between the actual postoperative model and the computer-generated outcome. All patients demonstrated satisfactory clinical outcomes. The mean repeatability was 87.5% within 1 mm and 96.5% within 2 mm in isolated bone graft. It was 71.4% within 1 mm and 89.9% within 2 mm in reconstructed mandible or maxilla. These results demonstrated that a resin template based on virtual plan and rapid prototyping technique is a reliable messenger to translate from computer modeling to bedside surgical procedures. The repeatability of a virtual plan can be easily and quantitatively evaluated through our three-dimensional differential analysis method.

Establishment of submandibular gland allotransplantation model in miniature swine.

BACKGROUND: Autologous transplantation of the submandibular gland (SMG) into the temporal fossa with microvascular anastomosis has been successfully applied in severe xerophthalmia patients as a permanent tear substitute. However, severe xerophthalmia can be accompanied by salivary gland dysfunction, making such autotransplantation unsuitable. Therefore, SMG allotransplantation might be a solution. The aim of this study was to assess the technical feasibility of submandibular gland allotransplantation. METHODS: Twelve miniature swine were randomized to serve as donors or recipients. One SMG was transplanted between a donor and a recipient. The donor SMG was revascularized by microvascular anastomosis of its vascular pedicle to the recipient lingual artery and external jugular vein. The secretory duct was implanted into the vestibule of the mouth through a subcutaneous tunnel. No immunosuppressive agent was administered. The results were assessed by visual inspection of the secretion, and histopathological examination of the transplanted SMG. RESULTS: Technically, all surgical procedures were successful. Clear secretion flowed out of the duct as soon as blood supply of the transplanted submandibular gland was reestablished. The secretion of the gland lasted for 5 days. As expected, an acute rejection reaction occurred after surgery because no immunosuppressive agents were used. Secretion from the transplanted SMG ceased within 5 days. CONCLUSIONS: A model of SMG allotransplantation can be established in miniature swine. The technique of submandibular gland allotransplantation is feasible.

Improving the accuracy of mandibular reconstruction with vascularized iliac crest flap: Role of computer-assisted techniques.

While vascularized iliac crest flap is widely used for mandibular reconstruction, it is often challenging to predict the clinical outcome in a conventional operation based solely on the surgeon's experience. Herein, we aimed to improve this procedure by using computer-assisted techniques. We retrospectively reviewed records of 45 patients with mandibular tumor who underwent mandibulectomy and reconstruction with vascularized iliac crest flap from January 2008 to June 2015. Computer-assisted techniques including virtual plan, stereomodel, pre-bending individual reconstruction plate, and surgical navigation were used in 15 patients. The other 30 patients underwent conventional surgery based on the surgeon's experience. Condyle position and reconstructed mandible contour were evaluated based on post-operative computed tomography. Complications were also evaluated during the follow-up. Flap success rate of the patients was 95.6% (43/45). Those in the computer-assisted group presented with better outcomes of the mandibular contour (p = 0.001) and condyle position (p = 0.026). Further, they also experienced beneficial dental restoration (p = 0.011) and postoperative appearance (p = 0.028). The difference between postoperative effect and virtual plan was within the acceptable error margin. There is no significant difference in the incidence of post-operative complications. Thus, computer-assisted techniques can improve the clinical outcomes of mandibular reconstruction with vascularized iliac crest flap.

Pre-mental foramen mandibulotomy for resecting tumors of tongue base and parapharyngeal space.

BACKGROUND: Resection of tumors arising from the tongue base and the parapharyngeal space is difficult for exposure and manipulation because of their obscure location. The aim of this study was to evaluate the surgical approach of the pre-mental foramen mandibulotomy for resecting the tumors of tongue base and parapharyngeal space. METHODS: Fifty-one patients with tumors of tongue base and parapharyngeal space were treated using the mandibulotomy approach on the pre-mental foramen. In the present study, this technique was described in detail. The patients were followed up for three months to six years with a mean of 26 months. RESULTS: The tumors of tongue base and parapharyngeal space could be exposed clearly and be resected radically by surgical approach of pre-mental foramen mandibulotomy. The surgical complications were reduced. CONCLUSIONS: Compared to other surgical approaches, such as lateral mandibulotomy, midline mandibulotomy, the suprahyoid parapharyngeal approach, and paramedian mandibulotomy, we found that the pre-mental foramen mandibulotomy is the ideal choice for resecting the tumors of tongue base and parapharyngeal space.