Indications and surgical technique for distraction osteogenesis of the alveolar bone for augmentation prior to insertion of dental implants.

When bone is limited, short, ultra-short, or narrow implants help to restore oral rehabilitation with an acceptable long-term outcome. This becomes more difficult with severe vertical bone loss. Guided bone regeneration, onlay block transplantation, or sandwich osteotomy have been established to build up these defects. The alternative to the alveolar distraction osteogenesis (ADO) has only been established in some centers, with a standardized protocol. On the one hand, ADO is a biological procedure that allows almost a "restitutio ad integrum" when building up hard and soft tissue. On the other hand, there are clear indications, limitations, and complications of the procedure in the literature. In addition to the literature, concept of Tissue Regeneration by Alveolar Callusdistraction Cologne (TRACC), which has been practiced successfully for over two decades, will be presented for different indications.

Prophylactic removal of titanium osteosynthesis miniplates in patients after midface fractures - A retrospective cohort study.

The aim of the study was to evaluate prophylactic removal of titanium osteosynthesis miniplates in patients after midface fractures. Complaints after fracture treatment and complications after plate removal were analyzed, retrospectively. A total of 205 patients were included. Plate removal was performed in 99 cases. Complaints related to the osteosynthesis material resulted in more frequent plate removal (p < 0.001). Complications were noted in 22 patients after plate removal. Duration of plate removal did not correlate with postoperative complications. In 69 patients, plates were removed without previous symptoms. Of these patients, postoperative complications were recorded in 15 cases. In patients with complaints after osteosynthesis, complications after plate removal occurred in seven (23.3%) patients. Ectropia developed significantly more often with increasing age (p < 0.05). CONCLUSION: Within the limitations of the study it seems that prophylactic plate removal is a treatment option that is not associated with an increased complication rate.

Morphological Studies to Identify the Nasopalatine and Inferior Alveolar Nerve Using a Special Head and Neck MRI Coil.

OBJECTIVES: Procedures in oral and maxillofacial surgery bear a high risk of nerve damage. Three-dimensional imaging techniques can optimize surgical planning and help to spare nerves. The aim of this study was to investigate the diagnostic value of a 1.5 T magnetic resonance imaging (MRI) scanner with a dedicated dental signal amplification coil for the assessment of nerves in the oral cavity as compared with cone beam computed tomography (CBCT). METHODS: Based on 6 predefined criteria, the assessability of the inferior alveolar and nasopalatine nerves in CBCT and MRI with a dedicated 4-channel dental coil were compared in 24 patients. RESULTS: Compared with CBCT, MRI with the dental coil showed significantly better evaluability of the inferior alveolar nerve in the sagittal and axial plane and the nasopalatine nerve in the axial plane. In the sagittal plane; however, the assessability of the nasopalatine nerve was significantly better in CBCT as compared with MRI. Yet, pertaining to overall assessability, no significant differences between modalities were found. CONCLUSIONS: In this pilot study, it can be reported that 1.5- T MRI with a dedicated dental coil is at least equivalent, if not superior, to CBCT in imaging nerve structures of the stomatognathic system. CLINICAL RELEVANCE: Preoperative, 3-dimensional images are known to simplify and refine the planning and execution of operations in maxillofacial surgery. In contrast to computed tomography and CBCT, MRI does not cause radiation exposure while enabling visualization of all relevant hard and soft tissues and, therefore, holds an advantage over well-established techniques.

Airway-Associated Complications With and Without Primary Tracheotomy in Oral Squamous Cell Carcinoma Surgery.

PURPOSE: This study analyzes postoperative airway management, tracheotomy strategies, and airway-associated complications in patients with oral squamous cell carcinoma in a tertiary care university hospital setting. MATERIAL AND METHODS: After institutional approval, airway-associated complications, tracheotomy, length of hospital stay (LOHS), and length of intensive care unit stay were retrospectively recorded. Patients were subdivided in primarily tracheotomized and not-primarily tracheotomized. Subgroup analyses dichotomized the not-primarily tracheotomized patients into secondary tracheotomized and never tracheotomized. Associations were calculated using regression analyses. A multivariate regression model was used to determine risk factors for secondary tracheotomy. RESULTS: A total of 207 patients were included. One hundred fifty-three patients (73.9%) were primarily tracheotomized. Primarily tracheotomized patients showed longer LOHS [odds ratio (OR) 1.04, 95% confidence interval (CI) 1.01-1.07, P =0.008] but decreased need for reventilation within the intensive care unit stay (OR 0.39, 95% CI 0.15-0.99, P =0.05) compared with not-primarily tracheotomized patients. Within the not-primarily tracheotomized patients, secondary tracheotomized during the hospital stay was needed in 15 of 54 patients (27.8%). In secondary tracheotomized patients, airway management due to respiratory failure was required in 6/15 (40%) patients resulting in critical airway situations in 3/6 (50%) patients. Multivariate regression model showed secondary tracheotomy-associated with bilateral neck dissection (OR 5.93, 95% CI 1.22-28.95, P =0.03) and pneumonia (OR 16.81, 95% CI 2.31-122.51, P =0.005). CONCLUSION: Primary tracheotomy was associated with extended LOHS, whereas secondary tracheotomy was associated with increased complications rates resulting in extended length of intensive care unit stay. Especially in not-primarily tracheotomized patients, careful individualized patient evaluation and critical re-evaluation during intensive care unit stay is necessary to avoid critical airway events.

Surgical side infections of the tracheostomy - A retrospective cohort study of patients with head and neck cancer in intensive care.

This study was conducted to reveal the relevant risk factors for surgical site infections (SSI) of the tracheostomy in ICU tracheostomy patients with oncologic history. Retrospectively, medical and ICU records of patients who received open tracheostomy in a uniform manner were investigated. Of 187 consecutive patients in total, patients with a peri/post-operative antibiotic prophylaxis (POABP) experienced significantly more Organ-Space SSI, whereas patients with a POABP developed less Superficial Incisional SSI and Deep Incisional SSI. Neck Dissection (p = 0.025), especially the more levels are included, and POABP (p = 0.005) have a significant impact on the occurrence of an SSI of the tracheostomy. Deep incisional SSI significantly prolonged a patient's dependency on a ventilator (p = 0.045, M = 3.92, SD = 4.718). The difference between Superficial Incisional, Deep Incisional and Organ-Space SSI should be taken in consideration regarding risk evaluation and treatment. Furthermore, a gram-negative facultative anaerobic biofilm should be taken into consideration in treatment options and thus an escalation regarding antibiotic treatment as a POABP. For fulminant SSI of the tracheostomy the use of piperacillin/tazobactam or 3rd generation cephalosporines or carbapenems is recommendable.

3D-based buccal augmentation for ideal prosthetic implant alignment-an optimized method and report on 7 cases with pronounced buccal concavities.

OBJECTIVES: Screw-retained restoration of implants is advantageous for biological and esthetic reasons. Due to buccal concavities, however, this preferred type of restoration can only be used in about half of the anterior indications. Based on case series, an optimized method for the treatment of such indications is to be described; the clinical reliability is to be ascertained by means of measurements (before and after augmentation) and assigned to the current literature. MATERIAL AND METHODS: A case series of seven cases with buccal concavities of the anterior alveolar ridge were treated with optimized method, which is presented step-by-step until the prosthetic restoration. The depths of the bone concavities were measured and related to the bone gain after augmentation procedure respectively after implantation. RESULTS: Linear measurements of the buccal concavities showed an average undercut of 4 mm [SD ± 1.13]. After healing period of six months, the buccal concavities could be compensated bony to such an extent that implants could be inserted in correct position and angulation. On average, there was a horizontal bone gain of 3.7 mm [SD ± 0.59]. Even after implantation and another six months of healing, stable bone dimensions could be assumed with an average of 4.3 [SD ± 0.83] mm of bone gain compared to baseline. In six of the seven cases, the favorite screw-retained, one-piece full-ceramic restoration could be fixed on the implants. Due to the implant axis, one case had to be treated with a cemented two-part full-ceramic system. CONCLUSIONS: With the described optimized method the most favorable screw-retained restoration can also be used in situations with unfavorable concavities of buccal bone. Especially for this indication, a special form of the horizontal deficit, the customized bone regeneration with titanium meshes is highly reliable in terms of healing and extent of augmentation. However, long-term results and a study/control group are required to evaluate the effectiveness of the presented protocol. CLINICAL RELEVANCE: Since these situations require an augmentation that is up to 5 mm thick and a procedure that is as minimally invasive as possible appears to be necessary in the visible area, an optimized method is described in this publication.

A Volumetric and Morphological Analysis of Recurrent Odontogenic Keratocysts by Semiautomatic Segmentation.

PURPOSE: The authors conducted this study to provide morphological and volumetric data of recurrent odontogenic keratocysts of the upper and lower jaw to emphasize risk factors in accordance with their radiological appearance and guide clinical decisions for jeopardized patients. METHODS: By applying the open-source software "ITK-Snap" on cone-beam computed tomography images, volumetric measurements of histopathologically diagnosed recurrent odontogenic keratocysts could be performed. For statistical investigations, descriptive statistics and independent Student t test were performed. The intraclass correlation coefficient was used to assess intra- and inter-rater reliabilities. P values P  < 0.05 were considered significant. RESULTS: Forty patients (24 male and 16 female) were included in this study. Recurrent odontogenic keratocysts had a mean maximum diameter of 28.91 mm ± 12.00 mm and a mean volume of 4.48 cm3 ±â€Š4.29 cm3. According to morphology, irregular shape (P = 0.001; P = 0.005), unclear margin (P = 0.001; P = 0.001), multilocular morphology (P = 0.001; P = 0.001), and cortical bone exceedance (P = 0.001; P = 0.007) are statistically significantly associated with a larger cyst diameter and volume. Furthermore, significant differences by diameter and volume could be shown between patients with and without iliac crest graft reconstruction (P = 0.001; P = 0.001). CONCLUSIONS: Volumetric analysis reveals that recurrent odontogenic keratocysts show large diametric and volumetric extension that leads to complex reconstruction by iliac crest grafts, adding an argument that special attention should be paid to this entity and its recurrence. in case of difficult histopathological examination, lesions with irregular shape and margin, multilocular morphology, cortical bone exceedance, and clinically visible symptoms should be considered for close morphological and volumetric clinico- radiological follow-up.

Outcomes of the Nonendoscopic Transoral Approach to Subcondylar Mandible Fractures.

PURPOSE: The transoral approach (TRA) to subcondylar fractures without any endoscopic or transbuccal assistance is not a common technique. The purpose of this study was to measure and compare the quality of open reduction and internal fixation (ORIF) between the TRA and the retromandibular approach (RMB), including types and frequencies of postoperative complications. METHODS: In our retrospective cohort study, we enrolled a sample of patients with displaced subcondylar mandible fractures treated by ORIF. The predictor was the approach mode: TRA or RMB. In postoperative computed tomography (CT) data sets, we measured the angles of the condylar process in relation to references: 1) midline, 2) lateral ramus border, and 3) posterior ramus border. The primary outcome variable was the reduction outcome, which was calculated as the difference between the total of all angles of the operated side and the non-affected side. Secondary outcomes were postoperative complications extracted from patients' files. Other variables were age, gender, number of plates, operation time and a modified AO trauma score. In bivariate analysis, we compared the outcome between both groups. RESULTS: Sixty-four patients were included in total, with TRA performed in 50%. Patients with TRA were younger (31 vs 41, P = .003), and the trauma score was lower (1.9 vs 3.3, P < .001). Reduction outcome remained comparable between both techniques (mean 3.7° for both, P = .92). Complication rates were similar, although facial nerve palsy was absent for TRA (0 vs 4, P = .039). CONCLUSION: We suggest TRA for selected patients with displaced, single fragmented subcondylar fractures. Reduction outcome shows a comparable exactness to RMB, while TRA is safer for the facial nerve.

Volumetric and Morphological Analysis of Mandibular Condyles of Angle Class 2 and 3 Malocclusion Patients.

ABSTRACT: This study was conducted to provide diametric and volumetric data of mandibular condyles from patients with Angle class 2 and 3 malocclusions by semiautomatic segmentation based upon cone-beam computed tomography.Cone-beam computed tomography images of 79 patients were analyzed. By using the open-source software "ITK-SNAP", diametric and volumetric measurements of 158 mandibular condyles were performed. Descriptive statistics were calculated for all normally distributed variables. Correlations between patients with Angle class 2 and 3 were calculated with the independent Student t test. P values P < 0.05 were considered significant.Irrespective of the side, patients with class 2 malocclusion showed smaller mandibular condyles (right: 1.128 ±â€Š0.504 cm3; left: 1.222 ±â€Š0.596 cm3) than patients with class 3 (right: 1.504 ±â€Š0.361 cm3; left: 1.493 ±â€Š0.335 cm3). These results were reproducible also in accordance with the diametric measurement (class 2 right: 16.75 ±â€Š2.72 mm; left: 17.04 ±â€Š3.01 mm) (class 3 right: 18.24 ±â€Š2.54 mm; left: 18.32 ±â€Š2.13 mm). However, volumetric differences were highly statistically significant (right: P = 0.001; left: P = 0.018) while diametric differences were slightly significant for the right and not significant for the left side (right: P = 0.042; left: P = 0.053).Diametric and volumetric analyses offer important additional information based on 3D images of cone-beam computed tomography technology. Significant differences in diameter and volume of mandibular condyles could be assessed between different classes of malocclusion.

1.5 T MRI with a Dedicated Dental Signal-Amplification Coil as Noninvasive, Radiation-Free Alternative to CBCT in Presurgical Implant Planning Procedures.

PURPOSE: Cone beam computed tomography (CBCT) is considered both reliable and safe and provides reproducible results in guided dental implant planning procedures. However, it has weaknesses in soft tissue contrast and is associated with radiation exposure. Recent studies showed promising results with magnetic resonance imaging (MRI) as a possible noninvasive, radiation-free, alternative imaging modality for dental indications. The purpose of this study was to evaluate the quality of 1.5 T MRI with a dedicated dental signal-amplification coil in comparison to CBCT for dental implant planning procedures. MATERIALS AND METHODS: Sixteen subjects undergoing preoperative MRI (3D HR T1w TSE and 3D HR T1w FFE) and CBCT were included in this prospective study. All imaging data were used for dental implant planning procedures using commercially available software. Two experts scored the planning as "ideal," "improvable," or "unacceptable." Furthermore, quantitative distances according to EuCC recommendations were collected. Finally, discrepancies between CBCT and 3D HR T1w TSE were analyzed. Statistical analysis was performed using the Mann-Whitney U test and analysis of variance (ANOVA). RESULTS: The dental implant planning procedure was technically feasibly using all imaging data. CBCT allowed for "ideal" placement in all cases. Ratings for 3D HR T1w TSE and 3D HR T1w FFE were 81.9%, 18.1%, and 0% and 54.2%, 30.0%, and 15.3% for ideal, improvable, and unacceptable, respectively, identifying 3D HR T1w TSE as superior compared with 3D HR T1w FFE. Head-to-head comparison between CBCT and 3D HR T1w TSE revealed no significant differences regarding the apical position of the implant of 1.2 ± 0.7 mm and 1.3 ± 0.5 mm coronally, respectively (P = .287). The deviation of the planed angle was 3.0 ± 1.2 degrees. In these merged data sets, the distance to the mandibular canal was significantly higher with 1.3 ± 0.8 mm, indicating better utilization of the existing bone. CONCLUSION: Within the limits of this pilot study, it can be reported that the dental image planning procedure is feasible using 1.5 T MRI with a dedicated dental coil and specific MRI sequences.

Anatomical and volumetric analysis of fibro-osseous lesions of the craniofacial skeleton.

PURPOSE: Our study aimed to provide volumetric data relating to fibro-osseous lesions of the craniofacial skeleton, in order to highlight risk factors due to the different entities, and to guide clinical decisions for jeopardized patients. METHODS: Volumetric measurements of osteomas and ossifying fibromas were performed by applying the open-source software ITK-Snap to cone-beam computed tomography images. DICOM datasets were imported, identified, and delineated using semiautomatic segmentation; this was then verified using manual segmentation. The volumes of the lesions were computed automatically in cubic millimeters using the program. For statistical investigations, descriptive statistics and independent Student t-tests were performed. Additionally, Pearson's correlation was applied as a bivariate analysis. Values of p < 0.05 were considered significant. RESULTS: 45 patients (11 male and 34 female) were included in this study. The mean volumes were 10.02 ± 18.79 cm3 for osteomas and 4.80 ± 5.71 cm3 for ossifying fibromas (p = 0.016). Males (12.81 ± 20.38 cm3) presented significantly larger volumes than females (5.43 ± 10.32 cm3) (p = 0.042). With regard to shape, morphology, and affection of surrounding anatomical structures, irregular shape (p = 0.001; p = 0.037), multilocular morphology (p = 0.001; p = 0.037), nerve affection (p = 0.001; p = 0.002), tooth affection (p = 0.001; p = 0.594), cortical bone exceedance (p = 0.033; p = 0.001), and clinically visible symptoms (p = 0.004; p = 0.001) were statistically significantly associated with a larger volume of both entities. CONCLUSION: Volumetric analysis revealed that osteomas significantly exceeded the mean size of ossifying fibromas, supporting the argument that special attention should be paid to this entity. In cases of difficult histopathological examination, lesions with irregular shape, multilocular morphology, nerve and tooth affection, cortical bone exceedance, and clinically visible symptoms should be considered for close clinico-radiological follow-up, irrespective of the entity.

Volumetric Analysis and Clinical Outcome in 54 Patients with Retrobulbar Hematoma.

PURPOSE: Retrobulbar hematoma (RBH) is a rare but serious vision threatening emergency. We analyze the relationship between hematoma volume, visual impairment and outcome. METHODS: Fifty-four patients with RBH receiving orbital decompression were retrospectively included. Volumetric analysis of RBH was performed by semi-automatic segmentation based on preoperative CT scans using ITK-SNAP software. Best corrected visual acuity (BCVA) measurements were obtained and correlated in 2 groups (no light perception (NLP), severe visual impairment) with the hematoma volume. RESULTS: NLP was documented preoperatively in 5/28 and postoperatively in 9/43 patients. Preoperative NLP was significantly associated with a larger hematoma volume (P = .03) and higher hematoma/orbital volume ratio (P = .03). Postoperative severe visual impairment showed significant associations with a larger hematoma volume (P = .02) as well as higher hematoma/orbital volume ratio (P = .02). CONCLUSION: Eyes with severe visual impairment and large hematoma volumes preoperatively are at high risk of permanent vision loss. Hematoma volume calculation might represent an additional prognostic parameter for visual outcome after RBH.

An Innovative Approach for Preoperative Perforator Flap Planning Using Contrast-enhanced B-flow Imaging.

Precise perforator mapping of the epifascial and subcutaneous course of the perforator flaps, including the precise detection of the skin point, is mandatory for successful preoperative flap design and planning of supramicrosurgery. We investigated the effectiveness of contrast-enhanced B-flow (BCEUS) imaging for perforator mapping and preoperative perforator flap planning and compared it with B-flow ultrasound, contrast-enhanced ultrasound, and color Doppler ultrasound. Sixteen patients who received an individualized perforator flap reconstruction were included in the study. Preoperative perforator mapping includes the following structures: subfascial course of the pedicle, fascial penetration point, subcutaneous course (epifascial and subcutaneous), and perforator skin point. The precision of the preoperative perforator mapping was analyzed for color Doppler ultrasound, contrast-enhanced ultrasound, B-flow ultrasound, and BCEUS. Each technique was able to precisely display the subfascial course of the vascular pedicle, including the fascial penetration point. However, only BCEUS enabled precise mapping of the epifascial and subcutaneous (suprafascial) course, including the skin point of the perforators with a clear delineation. Precise knowledge of the suprafascial course of the perforators is mandatory for successful supermicrosurgery and perforator flap planning. BCEUS imaging facilitates full perforator mapping, which improves the safety of flap harvesting. However, BCEUS is technically demanding and requires an experienced sonographer.

Bisphosphonate application and volumetric effects on MRONJ lesions.

The purpose of this investigation was to analyze the volume of medication-related osteonecrosis of the jaw (MRONJ) lesions by semi-automatic segmentation of cone-beam computed tomography images, and correlate the results with the underlying diseases and applied medication. MRONJ lesions detected in cone-beam computed tomography images were assessed. The open-source software ITK-Snap enabled volumetric measurements of MRONJ lesions based on semi-automatic segmentation. Results were analyzed according to necrosis volume, localization, and gender. In addition, the underlying disease and the type of application of antiresorptive medication were investigated. Cone-beam computed tomography images of 66 patients were studied. 34 male and 32 female patients were included, with ages ranging from 50 to 93 years at the time of diagnosis. The mean volume was 993.24 ± 620.94 mm3: 484.73 ± 230.97 mm3 for the upper jaw and 1084.04 ± 625.74 mm3 for the lower jaw. The results indicated statistically significant differences between lesions of the upper and lower jaw, regardless of gender (p = 0.003). The analysis of differences between males and females did not show any significant results (p = 0.464), although males presented slightly larger lesions than females. With regard to the underlying disease, patients with osteoporosis presented larger volumes, whereas patients with malignant tumors presented smaller volumes. Nevertheless, no statistically significant differences according to the underlying disease (p = 0.313) were detected. However, patients with intravenous (iv) application showed statistically significantly larger lesions than patients who underwent oral or subcutaneous (s.c.) applications (p = 0.004). It seems that the osteonecrosis volume correlates with the applied antiresorptive agents. Larger MRONJ lesions should be expected in patients who receive intravenous antiresorptive therapy.

Mandible Fractures Associated With the Introduction of an E-Scooter-Sharing System.

ABSTRACT: With the introduction of an e-scooter-sharing system in Germany, standing electric scooters became popular modes of transportation in many urban areas. But the increase in popularity has resulted in an increase in traumatic injuries associated with e-scooter accidents. The purpose of this investigation was to determine the common fracture pattern of patients with mandible fractures as a result of an electric scooter accident. The authors performed a retrospective investigation of 52 patients who were admitted to the trauma unit of an oral and maxillofacial department from June until November 2019 with a fracture of the mandible. Our study investigated the first 6 months of e-scooter sharing system in a major city with more than 1 million inhabitants. Our cohort consists of 52 patients, 38 males, and 14 females with a mean age of 37 years. E-scooter related mandible fractures were with 21% the third biggest group, after physical assault and falls. 45% of these patients were intoxicated by alcohol. Furthermore, the majority of e-scooter patients presented more than one fracture of the mandible (73%). For our cohort, a typical combination of a symphysis or body fracture and bilateral affected ramus and/or condyle was the prevalent recorded fracture combination (55%) of e-scooter related traumata. Small scooter wheels, a speed of 15 miles or 20 kilometers per hour and the individual clinging to the handlebar falling predestinate these vehicles for accidents with craniofacial trauma. Among all cranio-facial traumas mandible fractures were mostly documented for e-scooter accidents. The severity of e-scooter related mandible fractures and their fracture pattern should be recognized by trauma units.

Retrospective analysis of open bedside tracheotomies in a German tertiary care university hospital.

OBJECTIVE: Open surgical tracheotomy performed beside (STB) is a standardized procedure in critical ill patients. The aim of the study was to evaluate perioperative complications and the safety of STB in a tertiary care university hospital setting. MATERIALS AND METHODS: Intra- and postoperative complications were retrospectively recorded and associations based on the evaluation of clinical and laboratory parameters were studied using regression analyses. RESULTS: A total of 562 patients were included. Early tracheotomy shortened ventilation time after tracheotomy (ventilation before STB ≤ 5 days: mean 9.2 ± 9.1 days; ventilation before STB ≥ 6 days: mean 11.5 ± 10.5 days, p = 0.0001). Overall complications were found in 30/562 cases (5.3%), major complications in 12/562 cases (2.1%). Significant risk factors for overall tracheotomy related complications were higher body mass index (odds ratio [OR] 1.04, 95% confidence interval [CI] 1.01-1.07, p = 0.02), lower CRP (OR 0.99, CI 0.99-1.00, p = 0.03), higher INR (OR 5.67, CI 1.27-25.34, p = 0.02), longer duration of operation (OR 1.03, CI 1.00-1.06, p = 0.04) and tracheotomy during extracorporeal membrane oxygenation (ECMO) support (OR 6.26, CI 1.21-32.44, p = 0.03). CONCLUSION: STB represents a safe surgical procedure, also suitable for patients with an increased risk profile. Careful evaluation of individual risk factors should be favored to reduce procedure related complications.

Survival outcomes after surgical treatment of oral squamous cell carcinoma.

OBJECTIVE: To identify the clinicopathological parameters that influence survival in patients with oral squamous cell carcinoma, in order to allow for the development of individualized surveillance programmes and reduce the delay in diagnosis of recurrence. MATERIALS AND METHODS: Retrospective chart review of 553 patients with a treatment-naïve primary oral squamous cell carcinoma, who underwent primarily curative intended surgery. Exclusion criteria were neoadjuvant radio(chemo)therapy, follow-up < 1 year, perioperative death, inoperable disease, synchronous multiple malignancies and inadequate information on clinicopathological parameters. RESULTS: The clinicopathological factors that influence overall survival, disease-free survival and locoregional control were calculated. In the multivariate survival analysis, the occurrence of recurrence, presence of extracapsular spread, T- and N-classification were shown to be independent risk factors for overall survival. CONCLUSION: The identification of these risk factors can lead to the development of individualized follow-up programmes based on risk stratification. This allows for the earliest possible diagnosis of relapse which is essential to offer the patient a realistic second treatment chance and to improve survival rates.

Volumetric Analysis of the Pterygopalatine Fossa by Semiautomatic Segmentation of Cone Beam Computed Tomography.

The aim of this study was to provide volumetric data of the pterygopalatine fossa by semiautomatic segmentation based upon cone beam computed tomography.Cone beam computed tomography (CBCT) images of 100 patients were analyzed. By using the open source software "ITK-Snap," the volumetric measurements of 200 pterygopalatine fossae were performed. For statistical investigations paired t test, and independent Student t test were performed. Also, the Pearsons chi-square test was applied. P values P < 0.05 were considered significant.The mean volume was 578.376 mm for the right and 560.979 mm for the left side. The results indicated statistically significant differences according to the right and the left pterygopalatine fossa, regardless of gender (P < 0.05). The analysis of differences between males and females did not show any significant results (P > 0.05), although males present a slightly larger volume than females. According to the median age (59 years), younger patients presented smaller volumes, whereas older patients presented larger volumes. Nevertheless, no statistically significant differences according to age (χ = 3.520; P > 0.05) could be found.Clinical intervention with the application of local anesthetics into the complex and vulnerable anatomy of the pterygopalatine fossa makes a thorough knowledge about the volumetric capacity indispensable. Therefore, the semiautomatic segmentation of CBCT images provides a useful, available and validated tool. Our results show that a final injected anesthetic volume larger than 1 ml exceeds the pterygopalatine fossa capacity considerably and could cause complications. To prevent this, volumetric analysis of this region can provide further information and enables an individualized patients' treatment.

Does SPECT Provide Incremental Value to CT or MRI in Assessing Mandibular Invasion by Oral Squamous Cell Carcinoma?

PURPOSE: Single photon emission computed tomography (SPECT) has been commonly used as an additional method to assess mandibular bone invasion in patients with oral squamous cell carcinoma (OSCC). In the present study, we measured the diagnostic validity of SPECT findings compared with the histologic findings. PATIENTS AND METHODS: We implemented a retrospective cross-sectional study and enrolled a sample of patients with OSCC adjacent to the mandible. The staging examinations included magnetic resonance imaging (MRI) and/or computed tomography (CT) and additional SPECT. The patients' medical records and imaging data were reviewed by 2 readers, and bone invasion was classified as positive or negative for each diagnostic method. The predictor was bone invasion found on CT and/or MRI compared with the combination of CT and/or MRI with either positive or negative SPECT results. The primary outcome variable was histologic bone invasion. Other variables of interest were clinicopathologic data, type of mandibular resection, and resection margin status. Bivariate tests were used to compare the diagnostic specificity, sensitivity, and accuracy of each imaging modality. RESULTS: The study enrolled 122 patients, with a mean age of 67 years (55% male; study period, January 2010 to December 2017). In 60 patients (49%), segmental mandibular resection was performed. The sensitivity and specificity for bone invasion were 100% and 39% for SPECT and 84% and 75% for CT and/or MRI. The negative results for bone invasion using SPECT did not match the false-positive CT and/or MRI results in 5% (n = 6 of 122). Positive SPECT findings, in addition to positive CT and/or MRI findings increased the sensitivity to 100% but decreased the specificity to 29% (P < .001). Considering only negative SPECT findings increased the specificity to 85% (P = .03), sensitivity remaining unaffected. The accuracy of CT and/or MRI alone was 80% and was 84% when combining CT and/or MRI and negative SPECT findings (P = .03). CONCLUSIONS: In oncologic staging with CT and/or MRI, the addition of SPECT provided only small benefits. Only negative SPECT results allowed for greater specificity and accuracy. The use of SPECT could be considered to rule out bone invasion in cases of radiologic uncertainty of positive CT or MRI findings.

Analysis of the Pterygomaxillary Fissure for Surgical Approach to Sphenopalatine Ganglion by Radiological Examination of Cone Beam Computed Tomography.

The pterygopalatine fossa (PPF) is a complex and paired anatomical structure located at the skull base. A clinically and surgically relevant structure located in the pterygopalatine fossa is the sphenopalatine ganglion. Electrical stimulation of the sphenopalatine ganglion is one possible method of treating cluster headache. The pterygomaxillary fissure (PMF) defines the pterygopalatine fossa laterally and determines the surgical approach. As part of preoperative surgical planning, each patient undergoes a preoperative head computed tomography or a cone beam computed tomography. In our study cone beam computed tomography images of 90 male and 110 female PMF were analyzed. Generally, males have a wider fissure than females. Moreover, a significant inter-subject difference could be shown between males and females. The analysis of the right and left PMF according to gender and age does not show any significant intra-subject differences. Following an established protocol for high-resolution CT images the measurements were classified into four fissure types and also analyzed according to gender and age. Fissure type I is significantly more often present in males, whereas the smaller fissure types (II, III, and IV) are significantly more often found in females. Older patients presented statistically significant more often with type I, whereas the younger patients showed more often the narrower types II and IV. Due to the fact that narrow fissures smaller than 2 mm could limit the insertion of neurostimulator implants in the PPF, special attention should be paid to females and younger patients during preoperative planning.