Application of computer-assisted navigation systems in oral and maxillofacial surgery

The oral and maxillofacial region has a complicated anatomy with critical contiguous organs, including the brain, eyes, vital teeth, and complex networks of nerves and blood vessels. Therefore, advances in basic scientific research within the field of intraoperative oral and maxillofacial surgery have enabled the introduction of the features of these techniques into routine clinical practice to ensure safe and reliable surgery. A navigation system provides a useful guide for safer and more accurate complex in oral and maxillofacial surgery. The effectiveness of a navigation system for oral and maxillofacial surgery has been indicated by clinical applications in maxillofacial trauma surgery including complex midfacial fractures and orbital trauma reconstruction, foreign body removal, complex dentoalveolar surgery, skull base surgery including surgery of the temporomandibular joint (TMJ), and orthognathic surgery. However, some fundamental issues remain involving the mobility of the mandible and difficulty in updating images intraoperatively. This report presents an overview and feasible applications of available navigation systems with a focus on the clinical feasibility of the application of navigation systems in the field of oral and maxillofacial surgery and solutions to current problems.

Deep Learning for Osteoporosis Classification Using Hip Radiographs and Patient Clinical Covariates

This study considers the use of deep learning to diagnose osteoporosis from hip radiographs, and whether adding clinical data improves diagnostic performance over the image mode alone. For objective labeling, we collected a dataset containing 1131 images from patients who underwent both skeletal bone mineral density measurement and hip radiography at a single general hospital between 2014 and 2019. Osteoporosis was assessed from the hip radiographs using five convolutional neural network (CNN) models. We also investigated ensemble models with clinical covariates added to each CNN. The accuracy, precision, recall, specificity, negative predictive value (npv), F1 score, and area under the curve (AUC) score were calculated for each network. In the evaluation of the five CNN models using only hip radiographs, GoogleNet and EfficientNet b3 exhibited the best accuracy, precision, and specificity. Among the five ensemble models, EfficientNet b3 exhibited the best accuracy, recall, npv, F1 score, and AUC score when patient variables were included. The CNN models diagnosed osteoporosis from hip radiographs with high accuracy, and their performance improved further with the addition of clinical covariates from patient records.

Multi-Task Deep Learning Model for Classification of Dental Implant Brand and Treatment Stage Using Dental Panoramic Radiograph Images

It is necessary to accurately identify dental implant brands and the stage of treatment to ensure efficient care. Thus, the purpose of this study was to use multi-task deep learning to investigate a classifier that categorizes implant brands and treatment stages from dental panoramic radiographic images. For objective labeling, 9767 dental implant images of 12 implant brands and treatment stages were obtained from the digital panoramic radiographs of patients who underwent procedures at Kagawa Prefectural Central Hospital, Japan, between 2005 and 2020. Five deep convolutional neural network (CNN) models (ResNet18, 34, 50, 101 and 152) were evaluated. The accuracy, precision, recall, specificity, F1 score, and area under the curve score were calculated for each CNN. We also compared the multi-task and single-task accuracies of brand classification and implant treatment stage classification. Our analysis revealed that the larger the number of parameters and the deeper the network, the better the performance for both classifications. Multi-tasking significantly improved brand classification on all performance indicators, except recall, and significantly improved all metrics in treatment phase classification. Using CNNs conferred high validity in the classification of dental implant brands and treatment stages. Furthermore, multi-task learning facilitated analysis accuracy.

Radiographic characteristics of the calcifying odontogenic cyst

4 additional cases of calcifying odontogenic cysts (COC) were reported, together with the radiographic interpretation of 138 cases from the literature. From the review of the literature and of our own cases, the root resorption is one of the most common diagnostic findings as is cystic radiolucency accompanied by radiopacities. Other radiographic characteristics, such as loculation, tooth divergency and bone resorption were emphasized.

Does a Retromandibular Transparotid Approach for the Open Treatment of Condylar Fractures Result in Facial Nerve Injury?

PURPOSE

The retromandibular transparotid approach (RMA) to condylar fractures of the mandible provides excellent access, but can increase the risk of complications. The aim of this study was to estimate the frequency of facial nerve paralysis (FNP) and associated postoperative complications after open reduction and rigid internal fixation (ORIF) of subcondylar fractures through the RMA.

MATERIALS AND METHODS

This was a retrospective cohort study of patients with condylar fractures requiring ORIF through the RMA. The inclusion criteria were 1) a medical record of surgical treatment of a subcondylar fracture by RMA; 2) preoperative and postoperative radiographs; 3) mental status permitting an adequate neuromotor examination; 4) absence of a post-injury or pretreatment functional facial nerve deficit; and 5) regular postoperative follow-up longer than 6 months with documentation of complications, functional results, and fixation stability. The predictive variables were age, gender, fracture site, fracture pattern, concomitant fractures, etiology, and plate types. The outcome variable was FNP. Univariate, bivariate, and multiple logistic regression statistics were computed.

RESULTS

Fifty patients with 55 displaced mandibular subcondylar fractures (35 men, 15 women; mean age, 44.5 yr; range, 17 to 87 yr) met the inclusion criteria. The condylar fracture involved the neck in 35 patients (63.6%) and the base in 20 patients (36.4%). The fracture pattern was deviation in 11 patients (20.0%), displacement in 23 (41.8%), and dislocation in 21 (38.2%). Precise ORIF with double-buttress fixation resulted in immediate functional recovery in all patients. Seven fractures (12.7%) were associated with FNP that resolved completely within 6 months. Further statistical analysis showed that dislocated and displaced condylar neck fractures were significant risk factors for postoperative FNP (P < .05). Other postoperative complications were minimal.

CONCLUSION

The RMA for subcondylar fractures is feasible and safe. Dislocated condylar neck fractures are associated with a highly increased risk of temporary postoperative FNP as a surgical complication.

The retromandibular transparotid approach for reduction and rigid internal fixation using two locking miniplates in mandibular condylar neck fractures

We evaluated the safety, efficacy, and morbidity associated with the treatment of displaced mandibular condylar neck fractures using a retromandibular transparotid approach to reduce and rigidly fix using two 2.0-mm locking miniplates. Our surgical inclusion criteria were: patient selection of open reduction and fixation, displaced unilateral condylar fractures with derangement of occlusion, and bilateral condylar fractures with an anterior open bite. The study group consisted of 19 patients who underwent surgery for 19 mandibular condylar neck fractures; patients were analyzed prospectively, with more than 6 months of follow-up, and were evaluated in terms of functional results, scar formation, postoperative complications, and stability of fixation. The results showed that functional occlusion identical to the preoperative condition and correct anatomical reduction of the condylar segments in centric occlusion, followed by immediate functional recovery, was achieved in all patients. No patient suffered from any major or permanent complication postoperatively, although there were two cases (11%) of temporary facial nerve palsy, which resolved completely within 3 months. Surgical scars were barely visible. The retromandibular transparotid approach with open reduction and rigid internal fixation for displaced condylar neck fractures of the mandible is a feasible and safe, minimally invasive surgical technique that provides reliable clinical results.

Identification of osteoporosis using ensemble deep learning model with panoramic radiographs and clinical covariates

Osteoporosis is becoming a global health issue due to increased life expectancy. However, it is difficult to detect in its early stages owing to a lack of discernible symptoms. Hence, screening for osteoporosis with widely used dental panoramic radiographs would be very cost-effective and useful. In this study, we investigate the use of deep learning to classify osteoporosis from dental panoramic radiographs. In addition, the effect of adding clinical covariate data to the radiographic images on the identification performance was assessed. For objective labeling, a dataset containing 778 images was collected from patients who underwent both skeletal-bone-mineral density measurement and dental panoramic radiography at a single general hospital between 2014 and 2020. Osteoporosis was assessed from the dental panoramic radiographs using convolutional neural network (CNN) models, including EfficientNet-b0, -b3, and -b7 and ResNet-18, -50, and -152. An ensemble model was also constructed with clinical covariates added to each CNN. The ensemble model exhibited improved performance on all metrics for all CNNs, especially accuracy and AUC. The results show that deep learning using CNN can accurately classify osteoporosis from dental panoramic radiographs. Furthermore, it was shown that the accuracy can be improved using an ensemble model with patient covariates.

Overcorrection in vertical alveolar distraction osteogenesis for dental implants

A decrease in bone height following alveolar distraction osteogenesis (DO) before implant placement is common, and can be severe when alveolar DO is performed soon after surgical intervention. The aim of this study was to investigate the decrease in bone height after vertical alveolar DO and determine the need for overcorrection with implant placement. Thirty-five patients (17 males and 18 females, mean age 43.9 years) underwent 38 procedures with successful placement of 141 dental implants. Alveolar ridge height was evaluated using digital orthopantomographic radiographs taken shortly after the end of distraction, at consolidation and before implant placement. The mean distraction was 9.7 mm. The total vertical alveolar bone decrease was 2.1mm (21%) during the consolidation period and 3.6mm (37%) at implant placement. Although the 20 sites with a healthy alveolus (surgery >6 months) had bone reductions of 1.5 and 2.5mm (15 and 25%) the 18 sites at which alveolar DO was performed within 6 months (mean 3.0) of surgical intervention had much greater bone loss of 2.7 and 4.8mm (28 and 50%), respectively ((**)P<0.01). These results indicate that any alveolar DO protocol should include a waiting period after the surgical intervention, as well as consider an overcorrection of more than 25% within the limits of the applied surgical protocol.

Corticotomy and compression osteogenesis in the posterior maxilla for treating severe anterior open bite

A new technique is described for outpatient treatment of anterior open bite. The compression osteogenesis method with a two-stage corticotomy was used in the posterior maxilla to treat a woman with severe anterior open bite. Three-week post-surgical compression using anchor plates and elastics repositioned the posterior maxillary bone/teeth segments by 7 mm to the ideal superior position. The patient had a stable skeletal position of the maxilla at 14-month follow-up with satisfactory results and no complications after orthodontic treatment. This technique appears to be an efficient option for treating patients with anterior open bite.

Transoral open reduction with rigid internal fixation for subcondylar fractures of the mandible using a small angulated screwdriver system: is endoscopic assistance necessary?

PURPOSE

Although endoscopically assisted transoral open reduction and internal fixation of condylar mandible fractures is currently a popular technique, the need for it and its benefits remains unclear. This prospective study evaluated the efficacy and safety of open reduction and rigid internal fixation of subcondylar fractures of the mandible using a new small angulated screwdriver system without endoscopic assistance.

PATIENTS AND METHODS

Fifteen patients with 15 linear subcondylar fractures were treated using this intraoral approach from June 2007 through March 2010 at the Division of Oral and Maxillofacial Surgery, Kagawa Prefectural Central Hospital, Kagawa, Japan. The anatomic reduction of the displaced condylar segments and rigid fixation with 2 2.0-mm locking miniplates were performed using a small angulated screwdriver system, with an average follow-up of 13 months (range, 6 to 30 months).

RESULTS

Correct anatomic reduction of the condylar segments at centric occlusion followed by immediate functional recovery was achieved in all patients. Mean operating time was 50 minutes (range, 35 to 70 minutes) when performed by the consultant surgeon and the residents. In addition, all patients had good temporomandibular joint articular function, with no harmful clinical symptoms or deviation.

CONCLUSIONS

The surgical treatment of linear subcondylar fractures of the mandible can be achieved with an intraoral approach alone, using a small angulated screwdriver system, without endoscopic assistance, offering reliable clinical results and safe and minimally invasive surgery.

Complications of a poly-L-lactic acid and polyglycolic acid osteosynthesis device for internal fixation in maxillofacial surgery

The purpose of this study was to retrospectively evaluate and examine the incidence of complications using poly-L-lactic acid and polyglycolic acid (PLLA/PGA) copolymer plate system in maxillofacial osteosynthesis. The retrospective study included 87 patients (50 men, 37 women), who needed maxillofacial surgery. We examined the proportion of complications and their factors from clinical data. A comparison was also made for plate decomposition using the molecular weight of the plate without plate exposure and complications. Osteosynthesis sites healed in all patients. Ten cases (11.5%) showed plate exposure-related complications, with all occurring at intraoral surgical sites. There was no significant difference in molecular weight changes of plates in resorbable process. Statistical analysis of study variables between patients with and without exposed plates showed that the plate thickness was significantly associated with the risk of exposed plates (p < 0.05). The commercially available PLLA/PGA device could be a useful rapid resorbable material for maxillofacial osteosynthesis. When thick plates are used on the intraoral site, it may be necessary to pay attention to the complication of plate exposure. Even if exposure-related complications have occurred, resorption and degradation of this material proceeds, suggesting the ease of appropriate risk management.

Biomechanical Loading Evaluation of Unsintered Hydroxyapatite/poly-l-lactide Plate System in Bilateral Sagittal Split Ramus Osteotomy

OSTEOTRANS MX^® (Takiron Co., Ltd., Osaka, Japan) is a bioactive resorbable maxillofacial osteosynthetic material composed of an unsintered hydroxyapatite/poly-l-lactide composite, and its effective osteoconductive capacity has been previously documented. However, the mechanical strength of this plate system is unclear. Thus, the aim of this in vitro study was to assess its tensile and shear strength and evaluate the biomechanical intensity of different osteosynthesis plate designs after sagittal split ramus osteotomy by simulating masticatory forces in a clinical setting. For tensile and shear strength analyses, three mechanical strength measurement samples were prepared by fixing unsintered hydroxyapatite/poly-l-lactide composed plates to polycarbonate skeletal models. Regarding biomechanical loading evaluation, 12 mandibular replicas were used and divided into four groups for sagittal split ramus osteotomy fixation. Each sample was secured in a jig and subjected to vertical load on the first molar teeth. Regarding shear strength, the novel-shaped unsintered hydroxyapatite/poly-l-lactide plate had significantly high intensity. Upon biomechanical loading evaluation, this plate system also displayed significantly high stability in addition to bioactivity, with no observed plate fracture. Thus, we have clearly demonstrated the efficacy of this plate system using an in vitro model of bilateral sagittal split ramus osteotomy of the mandible.

Navigation-Assisted Orbital Trauma Reconstruction Using a Bioactive Osteoconductive/Bioresorbable u-HA/PLLA System

Orbital fractures with orbital wall defects are common facial fractures encountered by oral-maxillofacial surgeons, because of the exposed position and thin bony walls of the midface. The primary goal of surgery is to restore the pre-injury anatomy and volume of hard tissue, and to free incarcerated or prolapsed orbital tissue from the fracture by bridging the bony defects with reconstructive implant material and restoring the maxillofacial-orbital skeleton. Numerous studies have reported orbital fracture repair with a wide variety of implant materials that offer various advantages and disadvantages. The ideal orbital implant material will allow conformation to individual patients' anatomical characteristics, remain stable over time, and are radiopaque, especially for the reconstruction of relatively large and/or complex bony walls. Based on these requirements, novel uncalcined and unsintered hydroxyapatite (u-HA) particles and poly-L-lactide (PLLA; u-HA/PLLA) composite sheets could be used as innovative, bioactive, and osteoconductive/bioresorbable implant materials for orbital reconstruction. In addition, intraoperative navigation is a powerful tool. Navigation- and computer-assisted surgeries have improved execution and predictability, allowing for greater precision, accuracy, and minimal invasiveness during orbital trauma reconstructive surgery of relatively complex and large orbital wall defects with ophthalmological malfunctions and deformities. This review presents an overview of navigation-assisted orbital trauma reconstruction using a bioactive, osteoconductive/bioresorbable u-HA/PLLA system.

What are the risk factors for postoperative infections of third molar extraction surgery: A retrospective clinical study?

BACKGROUND

This study aimed to identify (1) the predilection site of postoperative infection after third molar extraction surgery, (2) risk factors associated with postoperative infection, and (3) the cause of the difference between delayed- and early-onset infections.

MATERIALS AND METHODS

This retrospective study included 1010 patients (396 male, 614 female) who had ≥1 third molars extracted (2407; 812 maxilla, 1595 mandible). The risk factors were classified as attributes, general health, anatomic, and operative. Outcome variables were delayed- and early-onset infections.

RESULTS

Postoperative infection was completely absent in the maxilla, and all infections occurred in the mandible, with a probability of 1.94% (31/1595). Bivariate analysis for postoperative infection showed depth of inclusion and intraoperative hemostatic treatment to be significantly associated with the development of infections. Bivariate analysis for delayed- and early-onset infections showed simultaneous extraction of the left and right mandibular third molars to be prominent risk factors.

CONCLUSIONS

Postoperative infection occurs mainly in the mandible, and that in the maxilla is very rare. The risk of postoperative infection in the mandible was found to be related to the depth of inclusion and intraoperative hemostatic treatment. Simultaneous extraction of the left and right mandibular third molars appear to increase the risk of delayed-onset postoperative infection.

Feasible Advantage of Bioactive/Bioresorbable Devices Made of Forged Composites of Hydroxyapatite Particles and Poly-L-lactide in Alveolar Bone Augmentation: A Preliminary Study

Purpose: We aimed to document the clinical usefulness of uncalcined and unsintered hydroxyapatite (u-HA) particles and poly-L-lactide (PLLA) composite materials and their advantageous properties. Methods: Between April 2016 and March 2018, five patients required anterior maxillary alveolar ridge augmentation using fixation with u-HA/PLLA screws for an onlay block bone graft harvested from the mandibular ramus at our institute. Bone biopsies were obtained from the dental implantation site following bone healing for histomorphometric and immunohistochemical (IHC) measurements. Results: Many stromal cells were positive for Osterix, RUNX2, and SOX9 but were negative for CD68. On cell counting, based on IHC staining for Osterix, RUNX2, SOX9 and CD68 from peripheral u-HA/PLLA screw or bone areas, both areas consistently showed no significant difference in terms of Osterix, RUNX2, and SOX9. Hematoxylin-eosin staining revealed direct bone connection to the biomaterials, and no inflammatory cells infiltrated the areas surrounding the bone or artificial material. Area between the bone and u-HA/PLLA screw was seamless with no boundary. Round small cells and immature fibroblasts were noted. The new bone showed the presence of bone lamellae, normal osteocytes, and osteoblasts. Conclusion: The u-HA/PLLA materials showed excellent biodegradability and bioactive osteoconductivity. In addition, this material induced no apparent inflammatory or foreign body reactions following implantation, and it directly bonded to the human bone. Therefore, this u-HA/PLLA material seems ideal and most suitable for use as a substitute for osteosynthesis.

Deep learning model for analyzing the relationship between mandibular third molar and inferior alveolar nerve in panoramic radiography

In this study, the accuracy of the positional relationship of the contact between the inferior alveolar canal and mandibular third molar was evaluated using deep learning. In contact analysis, we investigated the diagnostic performance of the presence or absence of contact between the mandibular third molar and inferior alveolar canal. We also evaluated the diagnostic performance of bone continuity diagnosed based on computed tomography as a continuity analysis. A dataset of 1279 images of mandibular third molars from digital radiographs taken at the Department of Oral and Maxillofacial Surgery at a general hospital (2014-2021) was used for the validation. The deep learning models were ResNet50 and ResNet50v2, with stochastic gradient descent and sharpness-aware minimization (SAM) as optimizers. The performance metrics were accuracy, precision, recall, specificity, F1 score, and area under the receiver operating characteristic curve (AUC). The results indicated that ResNet50v2 using SAM performed excellently in the contact and continuity analyses. The accuracy and AUC were 0.860 and 0.890 for the contact analyses and 0.766 and 0.843 for the continuity analyses. In the contact analysis, SAM and the deep learning model performed effectively. However, in the continuity analysis, none of the deep learning models demonstrated significant classification performance.

Which fixation methods are better between three-dimensional anatomical plate and two miniplates for the mandibular subcondylar fracture open treatment?

PURPOSE

To compare the clinical outcomes of a single three-dimensional (3-D) anatomical plate versus two conventional straight miniplates for the open treatment of mandibular subcondylar fractures.

METHODS

This retrospective clinical study included patients with mandibular subcondylar fractures treated by the retromandibular transparotid approach using a 3-D plate or two straight miniplates. Outcome variables included preoperative conditions of patients and fractures, extent of postoperative bone healing, and incidence of complications. Other variables included age, sex, fracture site, and follow-up duration. Variables were evaluated using descriptive statistics and compared between groups.

RESULTS

Twenty-eight fractures were analyzed: 13 fractures using 3-D plate and 15 fractures using two straight miniplates. None of the assessed variables showed significant differences between the two groups (p < 0.05). Unfortunately, in the 3-D plate group, reoperation was necessary for nonunion owing to plate breakage in one case with a bone defect around the fracture.

CONCLUSION

The 3-D plate and two straight miniplates were equally effective for the surgical management of mandibular subcondylar fractures. Although a 3-D plate is sufficient for a typical simple fracture, in cases with a bone defect around the fracture, selection of the plate fixation method should be carefully considered.

Surgical treatment of comminuted mandibular fractures using a low-profile locking mandibular reconstruction plate system

Objective:

The treatment of comminuted mandibular fractures is challenging due to the severity of associated injuries and the need for a careful diagnosis with adequate treatment planning. Recently, open reduction and stable internal fixation (OR-IF) with a load-bearing reconstruction plate have been advocated for reliable clinical outcomes with minimal complications. This clinical prospective study evaluated OR-IF in the surgical management of comminuted mandibular fractures with a new low-profile, thin, mandibular locking reconstruction plate.

Materials and Methods:

We prospectively assessed OR-IF of comminuted mandibular fractures with a low-profile locking mandibular reconstruction plate in 12 patients (nine men, three women; mean age 32.2 [range 16-71] years) between April 2010 and December 2011. The clinical characteristics and associated clinical parameters of patients were evaluated over a minimum follow-up period of 12 months.

Results:

Traffic accidents caused 50% of the fractures, followed by falls (25%). Four patients (33.3%) had associated midfacial maxillofacial fractures, while five patients had other mandibular fractures. Seven patients (58.3%) needed emergency surgery, mostly for airway management. Anatomical reduction of the comminuted segments re-established the mandibular skeleton in stable occlusion with rigid IF via extraoral (33.3%), intraoral (50%), or combined (16.7%) approaches. Immediate functional recovery was achieved. Sound bone healing was confirmed in all patients, with no complications such as malocclusion, surgical site infection, or malunion with a mean follow-up of 16.3 (range 12-24) months.

Conclusions:

OR-IF using a low-profile reconstruction plate system is a reliable treatment for comminuted mandibular fractures, enabling immediate functional recovery with good clinical results.

Adenosine 3',5'-cyclic monophosphate stimulates secretion of alpha-melanocyte-stimulating hormone from permeabilized cells of the intermediate lobe of the rat pituitary gland

The effect of Mg-ATP and cyclic AMP on the secretion of alpha-melanocyto-stimulating hormone (alpha-MSH) from electrically permeabilized cells of rat intermediate lobe (IL) were investigated. Addition of exogenous Ca2+ stimulated alpha-MSH secretion in a concentration- (EC50 = 4.8 microM) and temperature-dependent manner. This Ca2+-evoked secretion was further enhanced by Mg-ATP and cyclic AMP. Mg-ATP was required for the fully secretory response in the electrically permeabilized IL cells and the maximal secretion was reached at 1 mM. Cyclic AMP in the presence of GTP gamma S also potentiated Ca2+-evoked alpha-MSH secretion to the same magnitude as Mg-ATP. In the absence of Ca2+ both the cyclic AMP and Mg-ATP did not stimulate alpha-MSH secretion from IL cells. The data suggest that Mg-ATP and cyclic AMP may modulate directly the secretory components rather than change intracellular concentration of free Ca2+.

Effect of Patient Clinical Variables in Osteoporosis Classification Using Hip X-rays in Deep Learning Analysis

Background and Objectives: A few deep learning studies have reported that combining image features with patient variables enhanced identification accuracy compared with image-only models. However, previous studies have not statistically reported the additional effect of patient variables on the image-only models. This study aimed to statistically evaluate the osteoporosis identification ability of deep learning by combining hip radiographs with patient variables. Materials andMethods: We collected a dataset containing 1699 images from patients who underwent skeletal-bone-mineral density measurements and hip radiography at a general hospital from 2014 to 2021. Osteoporosis was assessed from hip radiographs using convolutional neural network (CNN) models (ResNet18, 34, 50, 101, and 152). We also investigated ensemble models with patient clinical variables added to each CNN. Accuracy, precision, recall, specificity, F1 score, and area under the curve (AUC) were calculated as performance metrics. Furthermore, we statistically compared the accuracy of the image-only model with that of an ensemble model that included images plus patient factors, including effect size for each performance metric. Results: All metrics were improved in the ResNet34 ensemble model compared with the image-only model. The AUC score in the ensemble model was significantly improved compared with the image-only model (difference 0.004; 95% CI 0.002–0.0007; p = 0.0004, effect size: 0.871). Conclusions: This study revealed the additional effect of patient variables in identification of osteoporosis using deep CNNs with hip radiographs. Our results provided evidence that the patient variables had additive synergistic effects on the image in osteoporosis identification.

Use of an intraoperative navigation system and piezoelectric surgery for styloidectomy in a patient with Eagle's syndrome: a case report

Background

Elongated styloid process syndrome (Eagle’s syndrome) is the term given to the symptomatic elongation of the styloid process or the mineralization of the stylohyoid or stylomandibular ligament. The two commonly used approaches for the surgical treatment of this syndrome are the transcervical and transoral approaches. Both have their limitations and specific intraoperative risks. Here, we report the treatment of a patient with Eagle’s syndrome using the transoral approach in conjunction with piezoelectric surgery, surgical planning, and intraoperative navigation to reduce the risk of complications.

Case presentation

The elongated styloid process was resected in a 45-year-old Japanese man using a minimally invasive approach with an intraoperative navigation system. Preoperative preparation involved the use of a custom interocclusal splint to produce the mouth opening conditions required during surgery. Using the three-dimensional position of the navigation probe, the location of the elongated styloid process was identified. After confirmation of the resection spot via the transoral approach, the styloid process was dissected by piezoelectric surgery. Follow-up examination showed an uneventful recovery with no associated complications.

Conclusion

The resection of the styloid process using an intraoperative navigation system and a custom interocclusal splint during a transoral approach, together with a piezoelectric cutting device, is safe and effective for the treatment of Eagle’s syndrome.

A radiographic study of recurrent unicystic ameloblastoma following marsupialization. Report of three cases

OBJECTIVES

To study the radiographic sequence in the recurrence of unicystic ameloblastoma following marsupialization.

MATERIALS AND METHODS

Retrospective analysis of three cases of uncystic ameloblastoma.

RESULTS

Six distinct stages were identified in all three cases: bone regeneration starting at the periphery of the cavity; appearance of a diffusely sclerotic band; appearance of scalloping; expansion of scalloping; formation of a multilocular pattern; and enlargement of the cystic lesion.

CONCLUSION

The first radiographic sign of recurrence is scalloping of the sclerotic margin of the regenerated bone.