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.

Incidental findings on craniomaxillofacial cone beam computed tomography in orthodontic patients.

PURPOSE: Cone beam computed tomography (CBCT) in orthodontics is increasingly used for detecting impacted or ectopic teeth or for orthognathic and cleft lip and palate treatment. Incidental findings (IFs) are frequently encountered and often relevant. The aim of this study was to detect the prevalence of relevant pathologies on CBCT scans of orthodontic patients. METHODS: Over a 6-year period, incidental imaging findings were analyzed in 345 CBCT scans (181 men; 164 women; age 16.3 ± 8.4 years), and subdivided into dental (Group 1), skeletal (Group 2), sinunasal (Group 3), and infrequent other pathologies (Group 4). RESULTS: A total of 502 IFs were detected in 345 patients (1.4 IFs per patient, on average). Most IFs were found in Group 1 (358 IFs; 71.3%), followed by Group 2 (129 IFs; 25.7%), Group 3 (14 IFs; 2.8%), and Group 4 (1 IF; 0.2%). There were 119 (34.5%) patients with a missing wisdom tooth, 94 (27.3%) with dental aplasia, 71 (20.6%) with dislocations, 33 (9.6%) with partial opacifications, and 27 (7.8%) with signs of sinusitis. CONCLUSIONS: This study found that IFs in orthodontic CBCT scans are frequently encountered, even in younger orthodontic patients. When interpreting CBCT scans, orthodontists should be aware of potential relevant IFs that may require further investigation, change patients' treatment or affect their quality of life.

Prevention and management of bacterial infections of the donor site of flaps raised for reconstruction in head and neck surgery.

PURPOSE: In the field of reconstructive head and neck surgery, surgical site infections (SSI) are commonly investigated for the recipient site of various reconstructive procedures. Data about SSI of the donor site of different flaps raised for reconstruction are rare. MATERIAL AND METHODS: With regard to the bacterial donor site infections, we retrospectively investigated the medical data, surgical reports and wound management protocols of 267 patients who received reconstruction of the head and neck after ablative surgery. All patients underwent reconstruction with one of the following flaps: free fasciocutaneous radial forearm flap (RFFF), free fasciocutaneous anterolateral thigh flap (ALTFF), pedicled myocutaneous latissimus dorsi flap (PLDF), pedicled myocutaneous pectoralis major flap (PPMF), free osteocutaneous fibula flap (FFF). Follow-up was conducted for 12 months. RESULTS: The lowest detection ratio (DR: number of infected sites/flaps raised from the respective donor site) was calculated for the radial forearm, 0.087. Pedicled flaps presented a moderate DR (PLDF: 0.27, PMMF:0.35). Donor sites of the leg possessed the highest DR (ALTFF:0.61, FFF: 045). Mainly gram-positive facultative anaerobic bacteria (n = 41) were detected and gram-negative bacteria (aerobe/anaerobe) were present in 27 cases. The most frequently detected bacteria were Staphylococcus spp., Viridans Streptococci, Pseudomonas aeruginosa and Escheria coli. Continuous wound management for in-hospital patients was able to prevent any local spreading or a prolonged length of in-hospital stay. CONCLUSION: Overall, gram-positive facultative anaerobic bacteria, mainly Staphylococcus spp., are the predominant bacteria detected in donor site wounds. For wound care management, an infection with gram-negative pathogens should not be neglected.

Supportive topical tranexamic acid application for hemostasis in oral bleeding events - Retrospective cohort study of 542 patients.

PURPOSE: Tranexamic acid (TXA) is widely used in the prevention of postsurgical oral bleeding. Tranexamic acid in addition to further surgical measures is widely utilized in prevention of post-surgical oral bleeding. The aim of the present study was to investigate: Can oral hemostasis be achieved by merely compression and topical application of tranexamic acid in different anticoagulant regimes among patients attending a general emergency department? Where are the limits to this procedure? Which has the greater impact on surgeons' choice for an invasive hemostatic approach-bleeding quality or oral anticoagulant therapy? MATERIALS AND METHODS: A retrospective cohort study of 542 patients who consecutively received treatment for oral bleeding was performed. We surveyed the values of the diverse hemostatic approaches. Special attention was granted to patient anticoagulant regimen and quality of the oral bleeding event. RESULTS: A total of 199 of 542 (36.7%) oral bleeding events were stopped by compression with a gauze or gauze soaked with TXA (4.8%). Stopping an oral bleeding event with wound compression can be improved by factor 1.6 if the gauze is soaked with tranexamic acid (4.8%), p ≤ 0.05. LMWH presented significantly more moderate bleeding than bloody oozing of the wound, p < 0.05. The quality of bleeding had a strong influence on oral surgeons' decisions to apply further surgical means. Sutures and native collagen fleeces were the favored methods to stop moderate and severe bleeding (p < 0.05). CONCLUSION: Topical application of TXA aids as a useful supportive tool to stop mild bleeding events such as the bloody oozing of an oral wound. The quality of an oral bleeding episode should be considered in the choice of hemostatic measure. Hemostatic approaches should begin with the least invasive procedure. TXA is a helpful tool.

Size distribution and clinicoradiological signs of aggressiveness in odontogenic myxoma-three-dimensional analysis and systematic review.

OBJECTIVES: Therapeutic assessment of odontogenic myxoma (OM) is poorly standardized. Unidimensional size criteria have shown to be unreliable in therapeutic decision-making. We evaluate the size distribution of OM and scan for associated clinicoradiological signs of aggressiveness. Additionally, we evaluate three-dimensional size delineation of OM aiming to improve future therapeutic assessment of this destructive neoplasm. METHODS: Primarily, we reviewed the database "PubMed" for data concerning the size of OMs as radiologically determined. Afterwards, the impact of age, sex, locularity and location on the size was investigated by χ² test, Student's t-test and regression analysis. Furthermore, we statistically evaluated the impact of size on the occurrence of clinicoradiological signs of aggressiveness. Secondly, we approximated the volume of five unpublished cases of OM by semi-automatic image segmentation of cone-beam CT images. RESULTS: Multilocular OMs were significantly larger than unilocular ones (p < 0.002). Age (0.042) and multilocularity (<0.002) significantly impacted size. Size was significantly associated with cortical perforation (0.032) and multilocularity (<0.002), further regression analysis revealed tooth resorption (0.019), cortical perforation (0.005) and multilocularity (<0.002) as significant predictors of size. Employing the volume as a mean of comparison, we found that the biggest OM (38.42 ml; multilocular) was 124 times larger than the smallest (0.31 ml; unilocular). However, using the maximum diameter (cm) as a surrogate for size, the biggest lesion (6.3) was only 5.25 times larger than the smallest (1.2). CONCLUSIONS: Locularity and volumetric size characterization might help in therapeutic decision-making and could help to improve our understanding of OM.

Lymph node ratio as prognosticator in floor of mouth squamous cell carcinoma patients.

BACKGROUND: Recently, lymph node ratio (LNR) has been recognized as an important prognosticator for oral squamous cell carcinoma (OSCC). However, its relevance for the specific subsite floor of mouth (FOM) has not been investigated. This study was conducted to elucidate the prognostic significance of LNR for the subsite FOM among other prognostic factors. METHODS: A retrospective study of 155 patients with FOM SCC who received primary curative resection and neck dissection was conducted. We analyzed the impact of LNR among other clinicopathologic variables on overall survival (OS) in univariate and multivariate analysis. RESULTS: In univariate analysis, patients detected with LNR ≤ 0.07 (cutoff-point: 0.07) showed an 85% 5-year OS rate, whereas for patients with LNR > 0.07 the OS rate reached 25% after 5-years (p < 0.001). The 5-year DFS rate was 72% for patients with LNR ≤ 0.07; on the contrary, patients with LNR > 0.07 the 5-year DFS rate was 17% (p < 0.001). LNR was detected as an independent predictor of OS in multivariate analysis (p = 0.032) for the subsite FOM. CONCLUSION: We concluded that LNR is an important predictor of prognosis in patients with FOM SCC, LNR should be considered in the choice of adjuvant treatment for these patients.

Systematic three-dimensional analysis of wafer-based maxillary repositioning procedures in orthognathic surgery.

PURPOSE: Little is known about the three-dimensional (3D) transfer accuracy in maxillary repositioning procedures based on conventionally manufactured dental-mounted wafers. The purpose of the present study was a systematic 3D analysis for wafer-based maxillary positioning in orthognathic surgery. MATERIALS AND METHODS: A total of 92 patients underwent Le Fort I in addition to mandibular bilateral sagittal split osteotomies (BSSO). Alignment of the pre- and postsurgical CBCT data sets allowed measuring maxillary position changes in axial, sagittal and transversal directions. RESULTS: The highest achieved absolute transfer inaccuracies were 1.37 mm, ±0.84 in the sagittal direction, followed by 1.15 mm, ±0.69 in the axial, as well as 1.05 mm, ±0.79 in the transversal direction. The largest relative deviations could be found for repositions in the transversal plane (109.4%, ±4.5), followed by the axial (66.2%, ±51.5) and sagittal plane (49.3%, ±2.2). Significant transfer accuracy differences of repositioning procedures in the sagittal direction, mainly advancement procedures, could be detected if performed with (1.75 mm, ±0.90) or without (1.18 mm, ±0.78) additional rotational correction component. No significant differences were found between unidirectional and multidirectional maxillary correction procedures. CONCLUSION: The present study for the first time delivers systematic 3D accuracy data of wafer-based maxillary positioning procedures, attesting to its feasibility but also further encouraging the search for improvement strategies.

The impact of surgical intervention and antibiotics on MRONJ stage II and III - Retrospective study.

OBJECTIVES: Metastatic bone disease and osteoporosis are the main indications for bisphosphonates and anti-resorptive agent therapy. Inhibition of bone turnover and angiogenesis are mainly responsible for the development of Medication Related Osteonecrosis of Jaws (MRONJ) as therapeutic side-effect. Yet, the role of infection for the development and recurrence of MRONJ is not fully elucidated. The aim of this retrospective study is to explore if a difference in antibiotic regimes has an impact on the surgical intervention needed to achieve a painless stable stage of the disease. Furthermore, we investigated concomitant submucosal infections in local relation to the MRONJ site. METHODS: A retrospective study (2006-2015) of 143 patients treated with MRONJ stage II and stage III in a single institutional university hospital was performed. All patients experienced at least one surgical intervention and received antibiotics. Their medical records, pathological and microbial findings were reviewed. Data was controlled for the achievement of an event free time period of at least 12 months. RESULTS: We investigated the number and kind of treatments that were performed on patients with MRONJ stage II and III to achieve a painless stable stage of the disease. The first and second healing approach differed significantly from each other (p < 0.05). In 7 (4.9%) cases up to four surgical interventions were needed to achieve oral rehabilitation. In 135 (95.1%) of all cases a segmental resection could be prevented, with extended decortication being the most applied method. Patients under perioperative ampicillin/sulbactam showed a significant reduction for a second or fourth intervention compared to the clindamycin group (p < 0.05). Results for a third intervention presented a similar difference between both groups, but were not significant (p = 0.06). Intraoperatively in 76 out of 241 (31.5%) cases presented putrid submucosal infections. The isolated bacteria were gram-negative facultative anaerobes (39.1%) and strictly anaerobic bacteria (gram-positive/38.2%, gram-negative/19.1%). Susceptibly of the cultured bacteria were significantly (p < 0.05) in favor to ampicillin/sulbactam (79.1%) compared to clindamycin (49.5%). CONCLUSION: The perioperative antibiotic regime for patients with MRONJ stage II and III undergoing surgically treatment does have an influence on the recurrence of the disease. Further investigation is needed to elucidate the role of infection in the treatment of MRONJ.

Can cyst volume be used to stratify risk of complications following cyst defect reconstruction with iliac crest graft?

INTRODUCTION: The role of the volume of radicular and dentigerous cysts on clinical symptoms is unclear and potentially may predict development of pre- and postoperative complications, especially after cystectomies with large bony defects. Therefore the aim of this study was to assess pre- and postoperative symptoms associated to the volume of jaw cysts. MATERIAL AND METHODS: Retrospective chart review of 111 patients with follicular or dentigerous cysts from 2008-2012. Anterior iliac crest grafts were used to fill defects after cystectomy. χ2-test was performed to analyze associations between two qualitative variables. Binary logistic regression analysis was used as multivariate analysis. P-values p < 0.05 were considered as significant. Volume measurement was performed in a semiautomatic segmentation method with the software "ITK-Snap". RESULTS: Postoperative hypaesthesia correlated significantly with histology (p = 0.025) and localization (p = 0.006). Volume was associated significantly with preoperative hypaesthesia (p = 0.052), postoperative hypaesthesia (p < 0.001), wound healing complications (p < 0.001) and length of wound healing complications (p = 0.001). Multivariate analysis identified volume as independent risk factor for postoperative hypaesthesia (p = 0.015). CONCLUSIONS: Volume analysis appears to be a method that allows risk stratification after surgery of jaw cysts. Therefore we recommend a precise treatment planning with the means of volume analysis to improve therapy outcome of patients with jaw cysts.

Odontogenic sinusitis maxillaris: A retrospective study of 121 cases with surgical intervention.

PURPOSE: Otolaryngologists, dentists and maxilla-facial surgeons see patients suffering from odontogenic maxillary sinusitis on a daily routine. The study was performed to investigate the different origins of the odontogenic maxillary sinusitis ranging from periodontitis to augmentative implant surgery. Furthermore, the microbial flora of purulent odontogenic maxillary sinusitis was analyzed in order to present a proper antibiotic treatment in addition to a surgical approach. MATERIALS AND METHODS: A retrospective study was performed, analyzing the clinical trials of 121 patients suffering from odontogenic maxillary sinusitis who undergone surgery. Harvested bacteria were tested for susceptibility on a routine base, surgical reports of removed foreign material or dental focus were reviewed as well as preoperative CBCT. RESULTS: Patients mean age was 56.62 (±16 SD) with a slight female gender dominance. Allergic profile to ß-lactam antibiotics had no influence on patients' length of in-hospital stay. 69 out of 121 cases of OMS occurred after dental surgery (extractions, augmentation or implant surgery). Maxillary molars were the teeth mostly hold accountable for an onset without surgery in recent history. 22.3% of the patients possessed a dislocated foreign body in the maxillary sinus. Pseudomonas aeruginosa infection was significantly associated with misplaced foreign bodies (root filling, augmentative dental material e.g. p < 0.05). We protocoled an anaerobic dominance with 45 anaerobes versus 19 aerobes. Ampicillin/Sulbactam (80%) and Piperacillin/Tazobactam (93.3%) present sufficient susceptibly rates to the harvested bacteria. Likewise showed Moxifloxacin (86.3%) equal results, whereas Clindamycin had a poor outcome with merely 50% of the tested bacteria being susceptible to Clindamycin. CONCLUSION: If OMS is diagnosed dental focus should be treated, misplaced bodies should be removed and purulent exacerbation has to be additionally treated with a calculated antibiotic therapy according to the pathogens resistance patterns.

Empiric systemic antibiotics for hospitalized patients with severe odontogenic infections.

INTRODUCTION: Odontogenic infections may lead to severe head and neck infections with potentially great health risk. Age, location of purulent affected sites and beta-lactam allergy are some mentionable factors regarding patients' in-hospital stay and course of disease. Are there new challenges regarding bacteria' antibiotic resistance for empiric treatment and what influences do they have on patients' clinical course? METHODS: We analyzed in a 4-year retrospective study the medical records of 294 in-hospital patients with severe odontogenic infections. On a routine base bacteria were identified and susceptibility testing was performed. Length of stay in-hospital was evaluated regarding patients' age, beta-lactam allergy profile, affected sites and bacteria susceptibility to empiric antibiotics. RESULTS: Length of stay in-hospital was detected to be associated with affected space and penicillin allergy as well (p < 0.05). Isolates presented large amounts of aerobic gram-positive bacteria (64.2%), followed by facultative anaerobic bacteria (gram+/15.8%, gram-/12.7%). Tested ampicillin in combination with sulbactam (or without) and cephalosporins displayed high susceptibility rates, revealing distinguished results regarding clindamycin (p < 0.05). Co-trimoxazol and moxifloxacin showed high overall susceptibility rates (MOX: 94.7%, COTRIM: 92.6%). DISCUSSION: This study demonstrates ampicillin/sulbactam in addition to surgical intervention is a good standard in treatment of severe odontogenic neck infections. Cephalosporins seem to be a considerable option as well. If beta-lactam allergy is diagnosed co-trimoxazol and moxifloxacin represent relevant alternatives. CONCLUSION: Age, allergic profile and bacteria' resistance patterns for empiric antibiotics have an influence on patients in-hospital stay. Ampicillin/sulbactam proves itself to be good for empiric antibiosis in severe odontogenic infections. Furthermore cephalosporins could be considered as another option in treatment. However moxifloxacin and co-trimoxazol deserves further investigation as empiric antibiosis in odontogenic infections if beta-lactam allergy is diagnosed.

Changes in volume during the four months' remodelling period of iliac crest grafts in reconstruction of the alveolar ridge.

Our aim was to assess the four months' resorption rates of onlay iliac crest grafts in atrophic jaws prospectively, and to identify factors that influence them. Twenty-four patients had reconstructions of the alveolar ridge with iliac crest onlay grafts at 30 sites on the mandibles and maxillas. The augmentation volumes were measured on cone-beam computed tomographic (CT) data-sets directly after augmentation (V1), and after four months' remodelling (V2). Statistical analysis allowed identification of potential influences from the recipient sites, volume of the graft, and the patients' smoking behaviour. The mean (range) initial onlay graft volume (V1) was 2.82 (0.66 to 6.41) ml. After four months, the mean measured onlay graft volume (V2) was 2.39 (0.47 to 6.21) ml. Mean iliac crest onlay graft volume resorption after four months of remodelling was 0.43 (-0.15 - 1.78) ml (15%). We found no significant differences in the resorption rates of iliac crest onlay grafts between different recipient sites (maxilla and mandible) or in dependence on the volume of iliac crest grafts. Smokers tended to have a higher rate of resorption, but not significantly so (p=0.056). The results of this study indicate the most favourable resorption rates for iliac crest onlay grafts that we know have seen published to date.

Prevention of post-operative bleeding in hemostatic compromised patients using native porcine collagen fleeces-retrospective study of a consecutive case series.

INTRODUCTION: Various anticoagulant therapy regimes bear the risk of postsurgical bleeding events after dental extractions. Local hemostyptic measures, e.g., collagen fleeces, are applied by surgeons to prevent such bleedings. No standard protocol in prevention of bleeding events has met general acceptance among surgeons yet. PURPOSE: The purpose of this retrospective study was to determine if post-operative bleeding can be prevented by suturing native collagen fleeces into extraction wounds immediately after teeth removal, regardless what anticoagulant regime is performed. METHODS: A total of 741 extraction units were removed from 200 consecutive in-ward patients with or without alternation of different anticoagulant therapy regimes. Anti-vitamin K agents were the most prescribed drugs (n = 104, 52 %), followed by Acetylsalicylate (ASS) (n = 78, 39 %). Nineteen (9.5 %) patients received a dual anti-platelet therapy. Out of 104 patients receiving an anti-vitamin K agent (phenprocoumon), 84 patients were bridged, 20 patients continued to their anticoagulant therapy without alterations. Following careful tooth extraction, extraction sockets were filled using a native type I and III porcine collagen sponge (Collacone, Botiss Biomaterials, Berlin), supported by single and mattress sutures for local hemostasis. Post-operative bleeding events were rated according to their clinical relevance. RESULTS: In the post-operative phase, 8 out of 200 consecutively treated patients experienced a post-operative bleeding event. All of them had been designated for a long-term anti-vitamin K therapy (p ≤ 0.05), and extractions were performed under a heparin bridging regime (n = 6) or an uninterrupted anti-vitamin K agent therapy (n = 2). No bleeding events occurred in patients with ASS 100 therapy or low-dose LMWH therapy (p ≤ 0.05), or in patients with dual anti-platelet therapy (0 out of 24). None of the bleeding events put patients' health at risk or required systemic intervention. CONCLUSION: Sufficiently performed local hemostyptic measures, like the application of collagen fleeces in combination with atraumatic surgery, bears a great potential for preventing heavy bleeding events in hemostatic compromised patients, regardless of their anticoagulant therapy.

The importance of early diagnosis in patients with maxillary sinus carcinoma.

There are two major challenges in the early diagnosis of maxillary sinus carcinoma: the maxillary sinus is not susceptible to direct inspection and palpation, and symptoms are uncharacteristic. The aim of this study was to assess the impact of the time interval between first symptoms noticed by the patient and the detection of the tumor on survival. 88 patients with maxillary sinus tumors were included in the retrospective study. Prognostic factors were identified through univariate analysis. Univariate analysis (p = 0.019) revealed a significant impact of the time interval from first symptom to diagnosis on overall survival. With increasing duration of the symptoms 5-year overall survival was reduced from 65 % for duration between 0 and 2 months to 24 % for duration of symptoms longer than 12 months. Furthermore, we found a significant association (p = 0.033) between local extension of the tumor and time interval from first symptom to diagnosis. Early diagnosis is often difficult because of uncharacteristic symptoms, which are identical with benign diseases of the maxillary sinus. The delay between the occurrence of the first symptom and diagnosis often makes a curative treatment impossible.

Prognostic quality of the Union Internationale Contre le Cancer/American Joint Committee on Cancer TNM classification, 7th edition, for cancer of the maxillary sinus.

BACKGROUND: Carcinomas of the maxillary sinus are classified according to the Union Internationale Contre le Cancer (UICC)/American Joint Committee on Cancer (AJCC) TNM classification. The purpose of this study was to assess the prognostic significance of the UICC/AJCC TNM classification seventh edition, which was introduced in 2010. METHODS: One hundred thirteen patients with malignant tumors of the maxillary sinus were included in this study. The prognostic impact of the TNM classification and the UICC/AJCC seventh edition's stage grouping were analyzed in univariate and multivariate analysis. RESULTS: The UICC/AJCC stage grouping, the T classification, and the N classification had a significant impact on overall survival (OS) in univariate analysis (p < .05). No significant differences were observed between the groups T4a and T4b (p = .109). In multivariate analysis, the UICC/AJCC stage grouping (p = .031), the N classification (p = .014), and age (p < .001) had a significant impact on OS. CONCLUSION: Although UICC/AJCC stage grouping and the N classification provided a significant prediction of OS in univariate and multivariate analysis, T classification only influenced OS in univariate analysis.

Computer-assisted orthognathic surgery: waferless maxillary positioning, versatility, and accuracy of an image-guided visualisation display.

There may well be a shift towards 3-dimensional orthognathic surgery when virtual surgical planning can be applied clinically. We present a computer-assisted protocol that uses surgical navigation supplemented by an interactive image-guided visualisation display (IGVD) to transfer virtual maxillary planning precisely. The aim of this study was to analyse its accuracy and versatility in vivo. The protocol consists of maxillofacial imaging, diagnosis, planning of virtual treatment, and intraoperative surgical transfer using an IGV display. The advantage of the interactive IGV display is that the virtually planned maxilla and its real position can be completely superimposed during operation through a video graphics array (VGA) camera, thereby augmenting the surgeon's 3-dimensional perception. Sixteen adult class III patients were treated with by bimaxillary osteotomy. Seven hard tissue variables were chosen to compare (ΔT1-T0) the virtual maxillary planning (T0) with the postoperative result (T1) using 3-dimensional cephalometry. Clinically acceptable precision for the surgical planning transfer of the maxilla (<0.35 mm) was seen in the anteroposterior and mediolateral angles, and in relation to the skull base (<0.35°), and marginal precision was seen in the orthogonal dimension (<0.64 mm). An interactive IGV display complemented surgical navigation, augmented virtual and real-time reality, and provided a precise technique of waferless stereotactic maxillary positioning, which may offer an alternative approach to the use of arbitrary splints and 2-dimensional orthognathic planning.

The role of clinical versus histopathological staging in patients with advanced oral squamous cell carcinoma treated with neoadjuvant radiochemotherapy followed by radical surgery.

INTRODUCTION: Several studies have questioned the prognostic accuracy of the TNM system for oral cancer since neither patient's comorbidity, specific tumor related factors nor multimodal treatment regimens such as preoperative radiochemotherapy (RCT) are incorporated. The present study was performed in order to evaluate the prognostic impact of cTNM and ypTNM in oral cancer patients treated with preoperative RCT and resection. METHODS: In this retrospective analysis a total of 139 patients (103 male, 36 female, average age 56.8 years) with oral squamous cell carcinoma (UICC II-IVb) were included. Treatment consisted of concomitant RCT with 39.6 Gy radiations and Carboplatin (cumulative dose 300 mg/m(2)) during the first week of radiation, as well as surgical tumor resection and neck dissection. RESULTS: During the mean follow up of 88.9 months 86 patients (61.9%) died. Locoregional recurrences occurred in 41 patients (29.5%). The 5 years overall survival rate was 45.5%. In univariate analysis margin status, ypT, ypN and ypUICC as well as complete pathological response revealed statistical significance on overall survival. In multivariate analysis ypT, ypN and margin status showed independent prognostic impact in our cohort. Neither cT nor cN provided statistical association with overall survival. CONCLUSION: Results indicate that the clinical staging status of advanced oral cancer prior to preoperative RCT and resection should be interpreted with caution in terms of prognosis.

Evaluation of the course of the inferior alveolar nerve in the mental foramen by cone beam computed tomography.

PURPOSE: Implant placement in the edentulous anterior mandible is frequently performed to stabilize prosthetic superstructures. The position of the inferior alveolar nerve (IAN), especially in an atrophic mandible, has to be considered to position implants properly. In this study, the prevalence of looping of the IAN was retrospectively determined to assess the need for imaging prior to implant placement in the anterior mandible. MATERIALS AND METHODS: Cone beam computed tomography scans of consecutive patients were evaluated to assess the prevalence and size of IAN looping. The results were compared with respect to patient age and sex as well as degree of atrophy and bone height at the mental foramen. RESULTS: Scans of 1,010 patients were obtained. IAN loops were found in 31% of the patients, with a significantly higher prevalence in male patients (33.1%) than in female patients (28.1%). The average size of loops was 1.4 ± 0.70 mm, with a maximum of 4.6 mm. For male patients, the average loop size was 1.6 ± 0.74 mm (maximum 4.6 mm), and for female patients an average dimension of 1.4 ± 0.63 mm (maximum 4.4 mm) was recorded. This difference was significant (t test). A significant difference with respect to the various classes of atrophy up to class 4 was not found. CONCLUSION: Loops of the IAN occur in about one third of patients and vary in size from 0.7 to 4.6 mm. Large anterior loops put the IAN at risk when interforaminal implants are placed. Either a sufficient safety distance or three-dimensional imaging procedures should be used to detect loops and locate the incisive canal, which could be harmed during the interforaminal implant placement.

CBCT device dependency on the transfer accuracy from computer-aided implantology procedures.

OBJECTIVES: To evaluate the potential influence of different cone-beam computed tomography (CBCT) devices on the transfer accuracy of an open-source system for computer-aided implantology (CAI). MATERIAL AND METHODS: A total of 108 implants in 18 partially edentulous patient-equivalent models were planned and fully guided implants were inserted using an open-source CAI system with three different CBCT devices. After follow-up CBCT and fiducial marker-matching procedure, linear horizontal, vertical, and maximal three-dimensional deviations, as well as angle deviations between the virtual planning data and the surgical results were calculated. Variance analysis was carried out to prove whether or not the observed differences between the CBCT devices were statistically significant. RESULTS: The observed mean three-dimensional deviation rates between virtually planned and achieved implant positions varied by around 400 µm (45%) at the implant's base and around 540 µm (50%) at the implant's tip in dependence to the applied CBCT device. Mean vertical deviations varied around 370 µm (76%) at the implant's base and 350 µm (69%) at the implant's tip, whereas axes deviations varied around 0.81° (40%) between the three investigated CBCT devices. Except for the axes deviations and the horizontal linear deviations at the implants base, observed differences reached significance level between the CBCT devices. CONCLUSIONS: Until now, the potential influence from different CBCT devices on the transfer accuracy of CAI systems has not yet been investigated. Data from the present study confirm for the first time the in vitro CBCT device dependency on the transfer accuracy of CAI systems reaching up to axes deviations of 0.6 angle degree and linear deviations around half a millimeter.

Preoperative vs. postoperative radiochemotherapy in patients with N2 squamous cell carcinoma of the oral cavity.

BACKGROUND: The aim of our study was to evaluate retrospectively whether neoadjuvant or adjuvant radiochemotherapy yields better survival for patients with N2-oral squamous cell carcinoma and to identify subgroups, which may benefit from one of the therapeutic settings. No studies have been carried out to investigate whether radiochemotherapy should be applied before or after surgery. METHODS: In total, 151 patients with oral squamous cell carcinoma with N2-nodal-status were reviewed. Eighty five patients received neoadjuvant radiochemotherapy, 66 patients were treated with surgery and adjuvant radiochemotherapy. Overall survival was plotted by Kaplan-Meier analysis. Prognostic factors were identified through univariate and multivariate analysis. RESULTS: Patients treated with neoadjuvant radiochemotherapy had a significantly improved 5-year survival in comparison to patients, who received adjuvant radiochemotherapy (46.3% vs. 27.4%, p=0.035). A subgroup analysis by T-stage revealed that neoadjuvant and adjuvant radiochemotherapy yielded similar 5-year survival rates for patients with T2N2-tumors (42.3% vs. 41.2%, p=0.871), whereas patients with T4bN2-tumors significantly benefitted from neoadjuvant treatment (37.3% vs. 9.7%, p=0.019). CONCLUSIONS: Neoadjuvant radiochemotherapy is an effective treatment for patients with nodal status N2-oral squamous cell carcinoma, however prospective randomized trials are needed to confirm, which patients should be treated with neoadjuvant or adjuvant radiochemotherapy.