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Endoscope-assisted surgery is becoming a preferred technique in salivary gland surgery. However, this technique has not yet been applied in submandibular gland (SMG) preservation surgery. This retrospective study was performed to evaluate the outcomes of endoscope-assisted gland-preserving surgery through a hairline incision in patients with benign SMG tumours. The study included 38 patients with benign SMG tumours who underwent tumour excision with gland preservation: 19 who underwent local excision of the tumour through an endoscope-assisted hairline approach and 19 who received the conventional cervical approach. The feasibility of the surgical procedure, perioperative patient variables, and postoperative appearance and functional outcomes were evaluated. Patients in both groups had their tumours removed successfully with tumour-free margins. The intraoperative blood loss, postoperative amount of drainage, mean length of the incision, and unstimulated saliva flow rate did not differ between the two groups. There was no difference in the stimulated saliva flow rate between the preserved gland and unaffected SMG. The aesthetic result was better in the endoscope-assisted hairline incision group. No tumour recurrence occurred during follow-up (range 12-52 months). Thus, gland-preserving tumour dissection appears to be a safe method for benign SMG tumours, with good functional results. Furthermore, the endoscope-assisted hairline incision is a feasible method with excellent cosmetic results.

The purpose of this ambispective study was to investigate whether deep learning-based automatic segmentation and landmark detection, the SkullEngine, could be used for orthognathic surgical planning. Sixty-one sets of cone beam computed tomography (CBCT) images were automatically inferred for midface, mandible, upper and lower teeth, and 68 landmarks. The experimental group included automatic segmentation and landmarks, while the control group included manual ones that were previously used to plan orthognathic surgery. The qualitative analysis of segmentation showed that all of the automatic results could be used for computer-aided surgical simulation. Among these, 98.4% of midface, 70.5% of mandible, 98.4% of upper teeth, and 93.4% of lower teeth could be directly used without manual revision. The Dice similarity coefficient was 96% and the average symmetric surface distance was 0.1 mm for all four structures. With SkullEngine, it took 4 minutes to complete the automatic segmentation and an additional 10 minutes for a manual touchup. The results also showed the overall mean difference between the two groups was 2.3 mm for the midface and 2.4 mm for the mandible. In summary, the authors believe that automatic segmentation using SkullEngine is ready for daily practice. However, the accuracy of automatic landmark digitization needs to be improved.

The aim of this study was to evaluate the feasibility and accuracy of occlusion-driven maxillary reconstruction with the deep circumflex iliac artery (DCIA) flap, using computer-assisted design and manufacturing (CAD/CAM) technology and intraoral anastomosis. The data of 11 patients who underwent occlusion-driven maxillary reconstruction with this method between December 2018 and December 2020 in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology were reviewed retrospectively. Postoperative complications and functional and aesthetic outcomes were recorded. The accuracy of the postoperative restoration was assessed using Geomagic Control 2014. Reconstruction was successful in nine patients; all were satisfied with their aesthetic and functional outcomes. One patient underwent extraoral anastomosis after failure of intraoral anastomosis. In another patient, the DCIA flap had to be removed after the operation because of flap failure. Among the 10 patients with DCIA flap success, colour map analysis showed a mean deviation of 0.40 ± 0.08 mm between the preoperative and postoperative craniomaxillary models. Thus, occlusion-driven maxillary reconstruction with the DCIA flap, using CAD/CAM technology and intraoral anastomosis, appears to be a feasible and accurate method for the repair of maxillary defects.

Craniomaxillofacial surgery has been experiencing a deep conceptual change in surgical planning over the last decade, with virtual reality technologies becoming widely adopted. The high demand has led to an exponential increase in available software. The aim of this review was to outline the current literature and provide evidence on the most used software for virtual surgical planning (VSP), and also to define contemporary knowledge on which procedures are more ready candidates for VSP. A search was performed in the major databases, and screening of the results according to the PRISMA statement identified 535 articles reporting the implementation of preoperative VSP during the years 2010-2020. A total of 77 different software programs were identified. The surgical procedures were assigned a standardized nomenclature and further simplified into 10 categories for analysis: temporomandibular joint (TMJ), implants (IMPL), malformations (MALF), reconstruction (REC), oncology (ONCO), oral surgery (ORAL), orthognathic surgery (ORTH), cranial surgery (CRANIO), trauma (TRAUMA), miscellaneous (OTHER). The journals they were reported in and the sample size of each study were also investigated. The results showed that the Materialise suite was the most widespread tool for VSP, with a prevalence of 36.3%, followed by the Geomagic family. Several packages were found to be associated with a specific type of surgical procedure. This review offers a synopsis of the array of VSP software reported in the literature and sets the basis for an informed, evidence-based use of this software in craniomaxillofacial surgery.

The aim of this study was to perform a timewise meta-analysis of randomized clinical trials (RCTs) comparing the outcomes of short implants (≤6 mm) versus lateral sinus floor augmentation followed by regular implants (≥10 mm) in the deficient posterior maxilla. Eleven RCTs with 1, 3, and 5 years of follow-up were reported in 21 articles. There was no significant difference in the implant loss rate at the patient level after 1 and 3 years between the two groups (risk ratio 0.50, P = 0.17; risk ratio 1.71, P = 0.51). After 5 years, the risk ratio was in favour of regular implants with augmentation and approached significance (3.28, P = 0.06). Excluding the results of two studies on ultrashort implants, the risk ratio for complications was in favour of short implants, but without significance (0.33, P = 0.08). Mean marginal bone loss was significantly lower at 1, 3, and 5 years for the short implants when compared to regular implants with augmentation. The residual osseointegration length of implants was between 3.4 mm and 5.9 mm in the short implants group and between 10.1 mm and 12.5 mm in the regular implants group after 5 years. In conclusion, short implants in the atrophic posterior maxilla demonstrate comparable outcomes to regular implants within the first 5 years. Patients who are fit for surgery should be informed about the risks and benefits of both options.

Three-dimensional positional changes of the temporomandibular joint after mandible reconstruction using microvascular fibula flaps were investigated in 58 patients. The results of preoperative virtually planned surgery, intraoperative resection- and cutting-guided surgery, and non-guided surgery were compared. Pre- and postoperative computed tomography data of each patient were processed and superimposed digitally. The condyle deviations and rotations along the axes and planes of the skull, as well as Euclidean distances, were determined. Reliability analyses, descriptive statistics, and non-parametric tests were performed with the alpha level set at P = 0.05. Reliability proved to be excellent for all variables. The median Euclidean distance was 2.07 mm for the left condyle and 2.11 mm for the right condyle. Deviations of ≥ 10 mm occurred in nine (16%) cases. The maximum deviation occurred in the horizontal plane and the least deviation in the sagittal plane. Median rotation was ≤ 1.4° around all axes. The condylar displacements did not differ significantly between the different surgical techniques investigated. The three-dimensional measurement method applied is highly reliable for evaluating the three-dimensional condylar position after mandibular reconstruction.

Facial symmetry plays an important role in facial attractiveness and is one of the major criteria used to determine attractiveness in humans. In craniomaxillofacial surgery, facial symmetry is one of the main considerations. The aim of this study was to determine anthropometric measurements quantitatively and investigate the relationship between facial symmetry and attractiveness in a local Malay population. The study included 30 photographed Malay individuals and 100 photograph assessors, all aged between 18 and 26 years. The assessors indicated their preferences regarding the more attractive face on original and manipulated (symmetrical face) photographs. None of the photographed subjects had a perfectly symmetrical face (asymmetry index (AI) of 0%); 33.3% of the photographed subjects had an AI in the range of 1.6-2.0%. The majority of assessors chose the manipulated symmetrical face as the most attractive (manipulated photograph selected in 91.2% of cases). As facial symmetry is considered a critical factor in attractiveness, it is beneficial to consider balance and symmetry prior to facial reconstruction. The AI values found in this study may be useful as guidance to determine the normal minimum balance of facial symmetry. No AI values indicating perfect symmetry were observed for the unedited facial anthropometric measurements. However, the projection of a perfectly symmetrical face does influence the perception of facial attractiveness.

Robotic assistance can help in physically guiding the drilling trajectory during zygomatic implant positioning. A new robot-assisted strategy for a flapless zygomatic implant placement protocol is reported here. In this protocol, a preoperative computed tomography scan is used to plan the surgical path. After surface registration, the ROSA robot (Zimmer Biomet Robotics) guides several steps, which are performed with shared control. The surgeon performs the drilling and tapping, guided by the robotic arm, which is positioned according to the planned trajectory. Placement of the zygomatic implant is done manually. Immediate intraoperative 3D verification is performed by cone beam computed tomography (flat-panel detector, Medtronic O-arm II). Four zygomatic implants were placed in the case patient according to the flapless protocol, with a mean vector error of 1.78 mm (range 0.52-4.70 mm). A screw-retained temporary prosthesis was placed on the same day. No significant complications were observed. The application of this robot-assisted surgical protocol, which guarantees a very high degree of precision, may reduce inaccuracies in the positioning of zygomatic implants that could deviate from the surgeon's plan. This appears to be a potentially safe flapless surgery technique. Drill slipping on the crest or on the maxillary wall is the main source of error in this procedure, emphasizing the usefulness of the assisted surgical guidance with haptic feedback.

Transverse maxillomandibular hypoplasia can be treated with surgically assisted rapid maxillary expansion (SARME) in association with mandibular symphyseal distraction (MSD). This paper introduces a hybrid mandibular Bologna midline distractor (BMD); the effectiveness of the distractor in combination with SARME for the treatment of transverse skeletal deficiency was evaluated. This two-centre study included 10 patients with a transverse arch width deficit7 mm and dental crowding, in both the maxilla and mandible, treated with SARME and MSD. The study design was partly retrospective (seven patients) and partly prospective (three patients). Frontal and lateral cephalometric analyses, as well as measurements on dental models, were performed at three different times: before treatment, after the distraction, and 6 months after postoperative orthodontic treatment. The cephalometric analyses and measurements on dental impressions confirmed a balanced and stable skeletal and dental mandibular expansion. An average symphyseal expansion of 7.8 mm was obtained, resolving dental crowding without dental extractions. In conclusion, mandibular expansion performed with the BMD in combination with SARME appears to be a viable surgical approach to transverse maxillomandibular hypoplasia. This technique allows the surgeon to obtain a balanced skeletal and dental expansion, with a low level of relapse.

The aim of this study was to evaluate the efficacy of marsupialization treatment for odontogenic keratocyst (OKC) and unicystic ameloblastoma (UA) based on the three-dimensional volumetric change over time, and to determine the difference between OKC and UA in terms of the absolute volume reduction (AVR) and absolute shrinkage speed (ASS), and whether they are correlated with the preoperative volume, time after marsupialization (time between marsupialization and second treatment), and patient age. This was a retrospective cohort study with a sample size of 60 patients: 29 with OKC and 31 with UA. Pre- and post-marsupialization cone beam computed tomography images were analysed using Mimics software. The volume reduction and shrinkage speed were analysed and correlated with the preoperative volume, time after marsupialization, and demographic data. Descriptive univariable and multivariable statistics were computed; significance was set at P ≤ 0.05. The mean percentage volume reduction after marsupialization was 67.6 ± 9.6% for OKC and 63.3 ± 20.1% for UA. There was no significant difference in AVR or ASS between the OKC and UA groups. For OKC and UA, the preoperative volume (both P 0.001) and time after marsupialization (P = 0.024 and P 0.001, respectively) were associated with AVR. Moreover, for OKC and UA, the preoperative volume and time after marsupialization were also significantly associated with the ASS (all P 0.001). For both lesions, patient age was not significantly related to AVR or ASS. Marsupialization appears to be a viable option to decrease the volume of OKC and UA. Age was found not to be associated with the volume reduction of either UA or OKC.

The aims of this study were (1) to evaluate the transparotid facial nerve dissection approach (TFND), in which the intraparotid cervicofacial or temporofacial division is identified first through a superficial lobe incision; and (2) to compare extracapsular dissection with a TFND (ECD-TFND) with partial superficial parotidectomy with a retrograde approach (PSP) for benign tumours in the tail of the parotid gland with respect to surgical outcomes. Eighty-nine patients underwent PSP or ECD-TFND for benign tumours in the tail of the parotid gland: 49 were treated surgically with PSP and 40 with ECD-TFND. The mean ( ± standard deviation) surgical time did not differ significantly between the groups: 64 ± 22.4 min for PSP and 59 ± 19.8 min for ECD-TFND (P = 0.302). There was a significant difference in sialocele: 18 (36.7%) patients in the PSP group and four (10%) in the ECD-TFND group (P = 0.002). There was also a significant difference in facial nerve injuries: temporary paralysis was observed in 13 (26.5%) patients in the PSP group and two (5%) in the ECD-TFND group (P = 0.007). It appears that TFND is a viable and safe approach when performing ECD for benign tumours in the tail of the parotid gland. ECD-TFND should be preferred over PSP for benign tumours in the tail of the parotid gland.

The purpose of this study was to assess the 1-year skeletal stability of the osteotomized maxilla after Le Fort I surgery, comparing conventional osteosynthesis with patient-specific osteosynthesis. Patients were assigned to a conventional or patient-specific osteosynthesis group using prospective randomization. The primary outcome was the three-dimensional change in postoperative skeletal position of the maxilla between the 2-week and 1-year follow-up cone beam computed tomography scans. Fifty-eight patients completed the protocol for the 2-week postoperative analysis, and 27 patients completed the 1-year follow-up study protocol. Of the 27 patients completing the entire protocol, 13 were in the conventional group and 14 in the patient-specific osteosynthesis group. The three-dimensional translation analysis showed that the use of the patient-specific osteosynthesis resulted in a skeletally stable result, comparable to that of conventional miniplate fixation. For both the patient-specific osteosynthesis and conventional miniplate fixation groups, median translations of less than 1 mm and median rotations of less than 1° were observed, indicating that both methods of fixation resulted in a stable result for the 27 patients examined. For the Le Fort I osteotomy, the choice between patient-specific osteosynthesis and conventional osteosynthesis did not affect the postoperative skeletal stability after 1 year of follow-up.

Microvascular free flaps are frequently used for head and neck reconstruction after prior neck dissection (ND) and neck irradiation (RTX). The aim of this study was to investigate the influence of ND and RTX on flap perfusion as a critical factor for flap success. Overall, 392 patients reconstructed with a microvascular fasciocutaneous flap (FF) or perforator flap (PF) in the head and neck region between 2011 and 2020 were analysed retrospectively. Flap perfusion measured intraoperatively and postoperatively with the O2C tissue oxygen analysis system was compared between patients who had received neither ND nor RTX (controls), patients who had received ND but no RTX (ND group), and patients who had received both ND and RTX (ND+RTX group). Intraoperative and postoperative flap blood flow was decreased in FFs in ND group patients compared to controls (median 66.3 AU vs 86.0 AU, P = 0.023; median 73.5 AU vs 93.8 AU, P = 0.045, respectively). In the multivariable analysis, these differences showed a tendency to persist (P = 0.052 and P = 0.056). Flap success rates were similar in control patients, ND patients, and ND+RTX patients (98.7%, 94.0%, and 97.6%, respectively). Flap perfusion is not reduced in FFs and PFs in patients who have undergone ND or ND and RTX. This indicates that neck dissection and neck irradiation should not be contraindications for microvascular free flap reconstruction.

The aim of this technical note is to describe a protocol for three-dimensional virtual simulation of orthognathic surgery that has been designed to be easily implemented, without the need for any special clinical apparatus, software brand, or computed tomography sequence. The protocol comprises innovative concepts and simplified steps for image segmentation, creation of a composite skull, control of the condylar position, and sequencing of bimaxillary surgery. This protocol was applied by the developers in about 2000 cases performed between 2015 and 2022, and has become quite popular among local surgeons. Previous preliminary studies have shown that it meets the accuracy standards for clinical use, although further studies with larger numbers of patients are desirable for additional validation.

Osteosarcoma is the most common bone sarcoma and is typically found in the distal femur, proximal tibia, and proximal humerus. While several factors are known to influence survival, less is known regarding the influence of primary tumor location. This study describes the clinical features and prognosis of mandibular osteosarcoma. The SEER database was utilized to identify cases of mandibular osteosarcoma diagnosed between 2004 and 2015. Sex, age, grade, histological subtype, tumor size, tumor extension, presence of metastasis at diagnosis, and therapeutic intervention were determined. Osteosarcomas originating from other sites were assessed for comparison. There were 164 cases of mandibular osteosarcoma identified, representing 5.5% of all surveyed osteosarcomas. The 2-, 5-, and 10-year overall survival rates were 79.9%, 65.6% and 58.5%, respectively. Survival was worse for patients with older age, larger tumor size, metastatic disease, and absence of surgical resection. Compared to other sites, mandibular osteosarcomas were significantly smaller tumors and were far less likely to metastasize. Mandibular osteosarcoma manifested at an older age than the more common extremity osteosarcomas and presented with smaller tumors. Rates of metastasis of jaw osteosarcoma were much lower than osteosarcoma found in the extremities, while mortality rates were comparable.

The aim of this study was to determine whether the autogenous dentin graft (ADG) shows comparable results and similar clinical performance to other graft materials when utilized for implant placement. Four databases were searched, and controlled human studies that applied autogenous dentin for implant surgery, comparing it with other bone grafts, were included. Nine articles met the inclusion criteria, five of which were randomized controlled trials and were included in the meta-analysis. ADG showed equivalent primary and secondary implant stability when compared to Bio-Oss (primary: mean difference -0.74, 95% confidence interval (CI) - 3.36 to 1.88, P = 0.58; secondary: mean difference - 1.29, 95% CI - 5.69 to 3.11, P = 0.57). The standardized mean difference (SMD) of marginal bone loss at 6 months and at the final follow-up (18 months) showed the two grafts to be similar (6 months: SMD -0.26, 95% CI -0.64 to 0.12, P = 0.18; final follow-up: SMD -0.12, 95% CI -0.50 to 0.26, P = 0.53), and survival after immediate implant placement was the same in the two groups: 97.37% and 97.30%, respectively. Incidences of complications with the autogenous dentin particles or blocks were in line with those of Bio-Oss or autogenous bone blocks, respectively. This meta-analysis indicates that the autogenous dentin graft is an effective option for bone augmentation around dental implants, with acceptable implant stability, marginal bone loss, and incidences of complications and failure.