Patient-specific beta-tricalcium phosphate scaffold for customized alveolar ridge augmentation: a case report : Case Report: patient-specific β-TCP scaffold for alveolar ridge CBR

BACKGROUND

Beta-tricalcium phosphate (β-TCP) is a biocompatible ceramic material widely used in the field of oral regeneration. Due to its excellent biological and mechanical properties, it is increasingly utilized for alveolar ridge augmentation or guided bone regeneration (GBR). With recent advances in computer-aided design and manufacturing (CAD/CAM), β-TCP can now be used in the form of digitally designed patient-specific scaffolds for customized bone regeneration (CBR) of advanced defects in a two-stage implant therapy concept. In this case report following the CARE case report guidelines, we present a novel application of a patient-specific β-TCP scaffold in pre-implant mandibular alveolar ridge augmentation.

CASE PRESENTATION

A 63-year-old female patient with significant horizontal bone loss in the posterior mandible was treated with a custom β-TCP scaffold in the context of a two-stage backward-planned implant therapy. Cone-beam computed tomography nine months after augmentation showed successful integration of the scaffold into the surrounding bone, allowing implant placement. Follow-up until two years after initial surgery showed excellent oral and peri-implant health.

CONCLUSIONS

This case highlights the potential of patient-specific β-TCP scaffolds for alveolar ridge augmentation and their advantage over traditional techniques, including avoidance of xeno-, allo-, and autografts. The results provide encouraging evidence for their use in clinical practice. Patient-specific β-TCP scaffolds may be a promising alternative for clinicians seeking to provide their patients with safe, predictable, and effective alveolar ridge augmentation results in customized bone regeneration procedures.

The Effectiveness of Three-Dimensional Osteosynthesis Plates versus Conventional Plates for the Treatment of Skeletal Fractures: A Systematic Review and Meta-Analysis

PURPOSE

To assess the difference between preformed anatomically shaped osteosynthesis plates and patient-specific implants versus conventional flat plates for the treatment of skeletal fractures in terms of anatomical reduction, operation time, approach, patient outcomes, and complications.

MATERIAL AND METHODS

MEDLINE (1950 to February 2023), EMBASE (1966 to February 2023), and the Cochrane Central Register of Controlled Trials (inception to February 2023) databases were searched. Eligible studies were randomised clinical trials, prospective controlled clinical trials, and prospective and retrospective cohort studies (n ≥ 10). Inclusion criteria were studies reporting the outcomes of preformed anatomically shaped osteosynthesis plates and patient-specific implants versus conventional flat plates after treating skeletal fractures. Outcome measures included anatomical reduction, stability, operation time, hospitalisation days, patients' outcomes, and complications. Two independent reviewers assessed the abstracts and analysed the complete texts and methodologies of the included studies.

RESULTS

In total, 21 out of the 5181 primarily selected articles matched the inclusion criteria. A meta-analysis revealed a significant difference in operation time in favour of the preformed anatomical plates and patient-specific implants versus conventional plates. Significant differences in operation time were found for the orbital (95% CI: -50.70-7.49, p = 0.008), upper limb (95% CI: -17.91-6.13, p < 0.0001), and lower limb extremity groups (95% CI: -20.40-15.11, p < 0.00001). The mean difference in the rate of anatomical reduction in the lower limb extremity group (95% CI: 1.04-7.62, p = 0.04) was also in favour of using preformed anatomical plates and patient-specific implants versus conventional plates.

CONCLUSIONS

This systematic review showed a significant mean difference in surgery time favouring the use of preformed anatomical plates and patient-specific implants for orbital, upper, and lower limb extremity fractures. Additionally, preformed anatomical plates and patient-specific implants in the lower limb group result in a significantly higher rate of anatomical reduction versus conventional flat plates.

Visualization of Inferior Alveolar and Lingual Nerve Pathology by 3D Double-Echo Steady-State MRI: Two Case Reports with Literature Review

Injury to the peripheral branches of the trigeminal nerve, particularly the lingual nerve (LN) and the inferior alveolar nerve (IAN), is a rare but serious complication that can occur during oral and maxillofacial surgery. Mandibular third molar surgery, one of the most common surgical procedures in dentistry, is most often associated with such a nerve injury. Proper preoperative radiologic assessment is hence key to avoiding neurosensory dysfunction. In addition to the well-established conventional X-ray-based imaging modalities, such as panoramic radiography and cone-beam computed tomography, radiation-free magnetic resonance imaging (MRI) with the recently introduced black-bone MRI sequences offers the possibility to simultaneously visualize osseous structures and neural tissue in the oral cavity with high spatial resolution and excellent soft-tissue contrast. Fortunately, most LN and IAN injuries recover spontaneously within six months. However, permanent damage may cause significant loss of quality of life for affected patients. Therefore, therapy should be initiated early in indicated cases, despite the inconsistency in the literature regarding the therapeutic time window. In this report, we present the visualization of two cases of nerve pathology using 3D double-echo steady-state MRI and evaluate evidence-based decision-making for iatrogenic nerve injury regarding a wait-and-see strategy, conservative drug treatment, or surgical re-intervention.

Two-versus three-screw osteosynthesis of the mandibular condylar head: A finite element analysis

Titanium screws are commonly used for osteosynthesis of mandibular condylar head fractures. Evidence suggests that the insertion of three screws may result in better fracture stability. Two screws only, on the other hand, could reduce adverse effects, mainly bone resorption. This study aimed to investigate the biomechanical differences in mandibular condylar head osteosynthesis with two versus three titanium screws using finite element analysis. A finite element model of the mandible with a right type P condylar head fracture fixed with two or three titanium screws was analyzed in ANSYS Mechanical. The geometry of the model assembly was constructed in ANSYS Spaceclaim. Biomechanical load boundary conditions were obtained from a validated musculoskeletal model in AnyBody Modeling System™. The preprocessing of the finite element model and mapping of the obtained boundary conditions was done in docq VIT. Fracture displacement, fragment deformation, von Mises stress distribution, and reaction forces within the screws were evaluated in ANSYS for three different loading scenarios. Finite element analysis showed similar results when comparing osteosynthesis with two versus three titanium screws for all three loading scenarios. Contralateral molar loading resulted in the highest stress on both the fracture and the screws with the maximum von Mises stress being found at the condylar neck. Stress concentration within the screws was found in the fracture gap and was higher in the lateral fragment. In all scenarios, maximum von Mises stress values were smaller when forces were distributed among three screws. However, stability was also adequate when two screws were used. Mandibular condylar head osteosynthesis with two titanium screws appears to provide sufficient fracture stability. Further clinical studies are needed to clarify the implications of these results.

Volumetric Evaluated Bone Resorption After Open Reduction and Internal Fixation of Condylar Head Fractures of the Mandible

PURPOSE

Decision making in the management of condylar head fractures remains difficult due to its dependency on multiple factors like fracture type, degree of dislocation, patient`s age and dental condition. As open reduction and internal fixation (ORIF) of condylar head fractures (CHFs) becomes more popular, the question of osteosynthesis removal is controversial. So far, information on volumetric changes after ORIF are available for a short-term period (<6 months) only. This study, therefore, was performed to assess bone resorption after condylar head fractures and to follow-up intermediate-term (>1 year) remodelling after removal of metallic osteosynthesis material. Furthermore clinical outcome was measured using Helkimo Index and put in relation with bone resorption.

MATERIALS AND METHODS

A retrospective analysis of 19 patients who underwent open reduction and internal fixation of condylar head fractures at the University Hospital of Zürich between January 2016 and April 2018 using intraoperative cone-beam computed tomography repositioning control was conducted. The bone resorption on the condylar head was measured in the course after removal of osteosynthesis material by segmenting and superimposing of the postoperative 3D radiologic follow-up exam (T2) over the initial intraoperative cone-beam computed tomography (T1) using iPlan-CMF software. Complementary Helkimo index was assessed to put resorption rate in relation to clinical outcome.

RESULTS

A total of 19 patients fulfilled the inclusion criteria. The mean follow-up time was 15.6 months and the mean bone resorption on the condylar head was -0.348cm³ or -15.29% of segmented condylar head. There was no correlation of clinical outcome and bone resorption.

CONCLUSIONS

Helkimo index showed satisfying results; therefore, ORIF of condylar head fracture proves as a feasible treatment option. The mean bone resorption rate of -15.29% in the intermediate-term follow-up time (mean 15.6 months) is comparable to findings of other studies with short-term follow-up time (< 6 months). Thus, postinterventional remodeling activity and resorption seems highest in the first 4 to 6 postoperative months with little further resorption. In prevention of negative sequelae of protruding implants, timing of osteosynthesis material removal after this period of high bone remodeling activity is recommended. The resorption rate showed no correlation to clinical outcome.

ASA score and procedure type predict complications and costs in maxillofacial reconstructive surgery: a retrospective study using a hospital administrative database

BACKGROUND

Reconstruction of osseous and soft tissue defects after surgical resection of oral cavity cancers can be achieved by a single-stage procedure with a microvascular bone flap or by a two-step approach with a soft tissue flap and subsequent bone augmentation. The therapeutic approach should be selected based on the patient&rsquo;s needs. Economic pressure requires preoperative risk assessment and estimation of the postoperative course. Flat-rate reimbursement systems via diagnosis-related groups with insufficient morbidity adjustments and financial sanction of medical complications might additionally cause false incentives in the choice of treatment.

OBJECTIVE

This study aimed to assess the influence of the type of flap chosen for maxillofacial reconstructive surgery on the total costs. Complication rates of different types of flap surgery and their prediction by a preoperative risk assessment tool (American Society of Anesthesiologists [ASA] score) were determined. Overall, the fairness of the current reimbursement system was rated.

METHODS

Patient characteristics, clinical data, and data on total costs and reimbursement of patients aged 18 years and older having undergone maxillofacial reconstructive flap surgery at the University Hospital of Zurich (Switzerland) between 2012 and 2014 were analysed. The preoperative risk was classified by the ASA score. Complications were graded according to the Clavien-Dindo classification system and the comprehensive complication index (CCI). Statistical analysis included Spearman and Pearson rank correlation, Kruskal-Wallis and Mann-Whitney nonparametric tests, and linear regression analysis.

RESULTS

129 patients were included in this study. Soft tissue flaps were performed in 82 patients, of which 56 were radial forearm flaps (43.4%), bone flaps in 41 patients, of which 32 were fibula flaps (24.8%), and combined flaps in 6 patients (4.7%). Patients with fibula flaps showed a significantly higher CCI and higher total costs. Higher preoperative ASA scores were significantly associated with increased length of stay, total costs and complications. Both the ASA score and reconstruction with a radial forearm flap were significant predictors of complications and total costs. Total median costs for radial forearm flaps were CHF 50,560 (reimbursement: CHF 60,851; difference: CHF 10,291) and for fibula flaps CHF 66,982 (reimbursement: CHF 58,218; difference: CHF &minus;8,764).

CONCLUSION

The ASA score allows a reliable preoperative assessment of patient outcomes and financial burden in maxillofacial reconstructive flap surgery. The type of flap reconstruction significantly influences complications and ultimately total costs. The current reimbursement system via diagnosis-related groups (DRGs) does not take sufficient account of this fact. Adaptations are therefore needed to prevent misplaced incentives to the detriment of patients.

[Cinematic Rendering in Cone Beam Computed Tomography: Advanced 3D Reconstructions of Dental and Maxillofacial Pathologies]

Cinematic rendering (CR) is a novel 3D visualisation technique, which provides photorealistic image reconstructions with a high level of image details. Aim of this case series is to show the application of CR in Cone Beam Computed Tomography (CBCT) in dentomaxillofacial pathologies. Four exemplary CBCTs of clinical dentomaxillofacial cases were selected. 3D CR reconstructions were generated from the CBCT by using a vendor-provided standard CR software. Cases include 1) external tooth resorption, 2) ankylosed maxillary molar tooth, 3) giant cell-associated osteolytic lesion of the mandible, 4) unilateral cleft lip/palate with additional skeletofacial deformity. CBCTs of four patients showing dental and osseous pathologies were successfully reconstructed. Overall, a subjectively improved 3D understanding of the presented pathologies was observed. The CR images seem to present more plasticity, giving a better feeling for the spatial depth of the tissue. CR can be applied to CBCT images in dentomaxillofacial patients. The photorealistic appearance might improve the understanding of complex anatomy or pathology, could facilitate patient communication, and might be helpful for advanced medical education. We see potential in the use of CR for additional 3D visualization. The actual image diagnosis is done in the classic sectional planes. The significance of CR reconstruction for image diagnostics must be investigated in appropriate studies.

Surgical Outcomes of Orbital Fracture Reconstruction Using Patient-Specific Implants

PURPOSE

Patient-specific implants (PSIs) are known to yield reliable outcomes in orbital wall fracture reconstruction (high precision, smoother operating techniques, and shorter surgical duration). This study analyzed the surgical error and clinical and esthetic outcomes of orbital reconstructions with PSIs.

METHODS

This ambispective cohort study enrolled patients who underwent orbital reconstruction using PSIs between October 2016 and January 2018. The study end points were surgical error, indication and duration of surgery, long-term sequelae, revision surgeries, and surgical complications. Surgical error was analyzed by superimposing the postoperative implant position onto the preoperative virtual plan. Both qualitative (heat map) and quantitative (distance) measurements were obtained.

RESULTS

Three patients were enrolled prospectively, and 23 were enrolled retrospectively. Indications for surgery were defect size (25 patients), diplopia (10 patients), impaired eye motility (4 patients), and significant enophthalmos (6 patients). At the last patient visit, there were 5 cases of diplopia, 1 case of exophthalmos, and 6 cases of slight enophthalmos of incremental degree. In terms of surgical error, a mean distance of 0.6 mm (95% confidence interval, 0.49 to 0.76), with a mean maximal distance of 3.4 mm (95% confidence interval, 2.79 to 4.02), was noted. No revision surgery was necessary. Lid malposition complications were not observed. However, 1 case each of symblepharon and scleral show were observed. No time-saving component was observed.

CONCLUSIONS

PSI use in orbital reconstruction guarantees a preplanned 3-dimensional anatomical shape with a mean surgical error of just 0.6 mm. Our clinical results were similar to those of other protocols; however, warranting a complex 3-dimensional anatomical shape also in large orbital fractures with a low mean surgical error is feasible by using PSIs.

Antimicrobial peptide gene expression in medication-related osteonecrosis of the jaw

Bisphosphonates and denosumab are commonly used antiresorptive therapies in patients with bone metastasis and osteoporosis. Medication-related osteonecrosis of the jaw (MRONJ) is a serious side effect of these drugs, and infection has been recognized as a contributing factor. Current therapeutic options for MRONJ show limited effectiveness, therefore necessitating novel treatment strategies. Bisphosphonates have recently been reported to induce the expression of antimicrobial peptides (AMPs), an inherent component of the immune system. Therefore, the aim of the present study was to investigate and compare the influence of the anti-RANKL antibody denosumab and bisphosphonates on the gene expression of selected AMPs: human α-defensin-1, human α-defensin-3, human β-defensin-1, and human β-defensin-3. Bone specimens were collected from patients with MRONJ who had been treated with bisphosphonates (n = 6) or denosumab (n = 6), and from healthy subjects (n = 6) with no history of treatment with bone metabolism-influencing drugs. Reverse transcription-quantitative polymerase chain reaction was used to quantify the expression levels of selected AMPs. Samples from patients treated with denosumab showed significantly higher mRNA expression of human α-defensin-3 and human β-defensin-3 than those from healthy subjects. This finding is similar to previously described upregulated expression of human defensins in patients with MRONJ after bisphosphonates treatment. This suggests that the elevated expression of defensins may be at least a part of the mechanism underlying the pathogenesis of osteonecrosis induced by antiresorptive therapies, which can serve as a new target for potential treatment of MRONJ.

3D-cinematic rendering for dental and maxillofacial imaging

OBJECTIVES

Aim of this technical note is to show the applicability of cinematic rendering (CR) for a photorealistic 3-dimensional (3D) visualization of maxillofacial structures. The focus is on maxillofacial hard tissue pathologies.

METHODS

High density maxillofacial pathologies were selected in which CR is applicable. Data from both, CT and cone beam CT (CBCT) were postprocessed using a prototype CR software.

RESULTS

CR 3D postprocessing of CT and CBCT imaging data is applicable on high density structures and pathologies such as bones, teeth, and tissue calcifications. Image reconstruction allows for a detailed visualization of surface structures, their plasticity, and 3D configuration.

CONCLUSIONS

CR allows for the generation of photorealistic 3D reconstructions of high density structures and pathologies. Potential applications for maxillofacial bone and tooth imaging are given and examples for CT and CBCT images are displayed.

[CAD/CAM Revolution in Craniofacial Reconstruction]

CAD/CAM Revolution in Craniofacial Reconstruction Abstract. The face is an important part of the personality and at the same time fulfils a variety of tasks. Aesthetics and function form a unique unit. The formation of the field of oral and maxillofacial surgery began in the first decades of the last century. It includes the prevention, diagnosis, therapy and rehabilitation of diseases, injuries, malformations and changes of the complex structures of the face, oral cavity, jaw and teeth. In the meantime, oral and maxillofacial surgery has arrived in the 21st century. Today's oral and maxillofacial surgery is a link between medicine and dentistry and a protagonist in the implementation of digital workflows in clinical care. Individual solutions with patient-specific implants are the rule, computer-assisted techniques support the surgeon in the planning and performing of surgical procedures. This article intends to give you an insight into how our patients benefit from advanced technologies.

Comparison of preseptal and retroseptal transconjunctival approaches in patients with isolated fractures of the orbital floor

Transconjunctival approach has become a standard procedure to access fractures of orbit and the infraorbital rim. The transconjunctival incision can be performed pre- or retroseptally. Both approaches have been described combined with modifications such as transcaruncular or detachment of the lateral canthus for wider exposure of the orbital walls and rim. Particularly concerning aesthetics, the transconjunctival approach shows advantages compared to the transcutaneous incisions, such as the transciliary and infraorbital access. Moreover, transconjunctival approach is preferred in the literature regarding lid retraction. In this study the preseptal approach is compared with the retroseptal approach concerning en- or ectropion, foreign body sensation and formation of symblepharon. In our collective complication rates were lower in the retroseptal transconjunctival group, although this was not statistically significant. Whether the preseptal or the retroseptal transconjunctival approach is selected, is rather based on the surgeon's preferences. Nevertheless, the retroseptal approach must be considered as advantageous alternative to the preseptal approach because of simpler surgical technique and the safer distance to the vulnerable lid apparatus.

Concept of patient-specific shape memory implants for the treatment of orbital floor fractures

PURPOSE

We will aim to develop implants made of a Ni-Ti shape memory alloy which can be applied for the treatment of midface fractures, such as isolated orbital floor fractures. These can then be implanted in a compressed form and unfold automatically in the body. With the help of newly developed application instruments, the implants can be applied along transnasal and transantral approaches into the maxillary sinus. Our objective is to evaluate the operation process and the functionality of these implants, already in a pre-investigation by an experienced surgeon on a phantom.

METHODS

The functionality of the surgical procedure and an implant prototype were both evaluated with the help of a realistic phantom. The minimally invasive application was carried out using the transnasal and transantral approach. Instruments and implant were rated individually on a scale, from -2 (not at all) to +2 (very good) for vaious criteria, such as the implants functionality or the ergonomics of the entire procedure. For a geometric comparison between the manufactured implant and the planned target geometry, the implants were scanned by micro-computed tomography. CAD models were derived from the scans by using reverse engineering.

RESULTS

Both the implants and the application procedure were assessed as good; thus, the implant concept is suitable for further development.

CONCLUSIONS

Implants made of shape memory alloys could allow in the future and allow less invasive access to treat orbital floor fractures. The implant design has to be modified that the implant can be stabilized and fixed with screws or a suture to avoid dislocation or implant loosening. The complication rates and risks of conventional orbital reconstructions should be lowered by this new method.

Patient-specific biodegradable implant in pediatric craniofacial surgery

Surgical correction of premature fusion of calvarial sutures involving the fronto-orbital region can be challenging due to the demanding three-dimensional (3D) anatomy. If fronto-orbital advancement (FOA) is necessary, surgery is typically performed using resorbable plates and screws that are bent manually intraoperatively. A new approach using individually manufactured resorbable implants (KLS Martin Group, Tuttlingen, Germany) is presented in the current paper. Preoperative CT scan data were processed in iPlan (ver. 3.0.5; Brainlab, Feldkirchen, Germany) to generate a 3D reconstruction. Virtual osteotomies and simulation of the ideal outer contour with reassembled bony segments were performed. Digital planning was transferred with a cutting guide, and an individually manufactured resorbable implant was used for rigid fixation. A resorbable patient-specific implant (Resorb X-PSI) allows precise surgery for FOA in craniosynostosis using a complete digital workflow and should be considered superior to manually bent resorbable plates.

Decelerated vascularization in tissue-engineered constructs in association with diabetes mellitus in vivo

AIMS

Rapid blood vessel ingrowth in transplanted tissue engineering constructs is the key factor for successful incorporation, but many potential patients who may use engineered tissues suffer from widespread diseases that limit the capacity of neovascularization (e.g. diabetes). Thus, in vivo vascularization analyses of tissue-engineered constructs in angiogenically affected organisms are required.

METHODS

We therefore investigated the in vivo incorporation of collagen-coated and cell-seeded poly-L-lactide-co-glycolide scaffolds in diabetic B6.BKS(D)-Lepr(db)/J mice using repetitive intravital fluorescence microscopy over a time period of two weeks. For this purpose, scaffolds were seeded with osteoblast-like or bone marrow mesenchymal stem cells and implanted into the dorsal skinfold chambers of diabetic and non-diabetic (C57BL/6) mice.

RESULTS

Apart from slightly increased inflammatory parameters, diabetic mice showed significantly reduced capillary densities compared with non-diabetic animals from day 6 onward. In line with previous studies, more densely meshed microvascular networks were demonstrated in cell-seeded than in collagen-coated scaffolds from day 6 onward within the single groups (diabetic and control).

CONCLUSIONS

A large number of patients who suffer from systemic diseases that affect angiogenesis would profit from tissue engineering. Therefore, the challenge for the clinical introduction of tissue-engineered constructs will be to overcome the decreased angiogenesis in diabetic organisms.

Predictability in orbital reconstruction. A human cadaver study, part III: Implant-oriented navigation for optimized reconstruction

Navigation-assisted orbital reconstruction remains a challenge, because the surgeon focuses on a two-dimensional multiplanar view in relation to the preoperative planning. This study explored the addition of navigation markers in the implant design for three-dimensional (3D) orientation of the actual implant position relative to the preoperative planning for more fail-safe and consistent results. Pre-injury computed tomography (CT) was performed for 10 orbits in human cadavers, and complex orbital fractures (Class III/IV) were created. The orbits were reconstructed using preformed orbital mesh through a transconjunctival approach under image-guided navigation and navigation by referencing orientating markers in the implant design. Ideal implant positions were planned using preoperative CT scans. Implant placement accuracy was evaluated by comparing the planned and realized implant positions. Significantly better translation (3.53 mm vs. 1.44 mm, p = 0.001) and rotation (pitch: -1.7° vs. -2.2°, P = 0.52; yaw: 10.9° vs. 5.9°, P = 0.02; roll: -2.2° vs. -0.5°, P = 0.16) of the placed implant relative to the planned position were obtained by implant-oriented navigation. Navigation-assisted surgery can be improved by using navigational markers on the orbital implant for orientation, resulting in fail-safe reconstruction of complex orbital defects and consistent implant positioning.

Predictability in orbital reconstruction: A human cadaver study. Part II: Navigation-assisted orbital reconstruction

Preformed orbital reconstruction plates are useful for treating orbital defects. However, intraoperative errors can lead to misplaced implants and poor outcomes. Navigation-assisted surgery may help optimize orbital reconstruction. We aimed to explore whether navigation-assisted surgery is more predictable than traditional orbital reconstruction for optimal implant placement. Pre-injury computed tomography scans were obtained for 10 cadaver heads (20 orbits). Complex orbital fractures (Class III-IV) were created in all orbits, which were reconstructed using a transconjunctival approach with and without navigation. The best possible fit of the stereolithographic file of a preformed orbital mesh plate was used as the optimal position for reconstruction. The accuracy of the implant positions was evaluated using iPlan software. The consistency of orbital reconstruction was lower in the traditional reconstructions than in the navigation group in the parameters of translation and rotation. Implant position also differed significantly in the parameters of translation (p = 0.002) and rotation (pitch: p = 0.77; yaw: p < 0.001; roll: p = 0.001). Compared with traditional orbital reconstruction, navigation-assisted reconstruction provides more predictable anatomical reconstruction of complex orbital defects and significantly improves orbital implant position.

Splintless orthognathic surgery: a novel technique using patient-specific implants (PSI)

In the past few years, advances in three-dimensional imaging have conducted to breakthrough in the diagnosis, treatment planning and result assessment in orthognathic surgery. Hereby error-prone and time-consuming planning steps, like model surgery and transfer of the face bow, can be eluded. Numerous positioning devices, in order to transfer the three-dimensional treatment plan to the intraoperative site, have been described. Nevertheless the use of positioning devices and intraoperative splints are failure-prone and time-consuming steps, which have to be performed during the operation and during general anesthesia of the patient. We describe a novel time-sparing and failsafe technique using patient-specific implants (PSI) as positioning guides and concurrently as rigid fixation of the maxilla in the planned position. This technique avoids elaborate positioning and removal of manufactured positioning devices and allows maxillary positioning without the use of occlusal splints.

Patient specific implants (PSI) in reconstruction of orbital floor and wall fractures

Fractures of the orbital wall and floor can be challenging due to the demanding three-dimensional anatomy and limited intraoperative overview. Misfitting implants and inaccurate surgical technique may lead to visual disturbance and unaesthetic results. A new approach using individually manufactured titanium implants (KLS Martin, Group, Germany) for daily routine is presented in the current paper. Preoperative CT-scan data were processed in iPlan 3.0.5 (Brainlab, Feldkirchen, Germany) to generate a 3D-reconstruction of the affected orbit using the mirrored non-affected orbit as template and the extent of the patient specific implant (PSI) was outlined and three landmarks were positioned on the planned implant in order to allow easy control of the implant's position by intraoperative navigation. Superimposition allows the comparison of the postoperative result with the preoperative planning. Neither reoperation was indicated due to malposition of the implant and the ocular bulb nor visual impairments could be assessed. PSI allows precise reconstruction of orbital fractures by using a complete digital workflow and should be considered superior to manually bent titanium mesh implants.

Efficacy of transcutaneous transseptal orbital decompression in treating acute retrobulbar hemorrhage and a literature review

Decreasing visual acuity secondary to orbital trauma may be caused by sudden space-occupying or expanding intraorbital lesions, including retrobulbar hemorrhage (RBH), herniation, or swelling. RBH must be diagnosed and treated immediately. This article addresses the efficacy of transcutaneous transseptal orbital decompression in a combination with a systematic review of the literature for a comparison of this method with existing treatment options. For this study the department's database was retrospectively screened for patients with acute RBH who were treated between 2009 and 2011 using the authors' approach. Patients presenting with RBH were classified into RBH classes I to III according to three different clinical and radiological manifestations of acute RBH. The efficacy of transcutaneous transseptal orbital decompression was assessed by postoperative visual acuities. The literature review was performed by using the MEDLINE database. The time period for the study was between 2009 and 2011 during which 10 patients were diagnosed with suspected RBH and 9 were treated with the authors' technique. Visual acuities were reconstituted or maintained in almost 86% of patients who were diagnosed and treated according to the authors approach and who survived initial trauma. It was concluded that transcutaneous transseptal orbital decompression provides an efficient and rapid approach for treating patients with acute RBH. By distinguishing three different manifestations of acute RBH, the authors present a diagnostic tool that may facilitate classification of RBH and determination of treatment options.

Precision of posttraumatic primary orbital reconstruction using individually bent titanium mesh with and without navigation: a retrospective study

Background

The aim of orbital wall reconstruction is to reestablish anatomically exact orbital volumes to avoid long-term complications. Navigation could facilitate complex reconstructions.

Methods

Quality of the orbital reconstruction (n = 94) was measured based on (A) volume changes and (B) on 3D shape deviations compared to the unaffected side. Volume analysis included segmentation of the orbital cavity in the pre- and post-operative 3D data set (VoXim®, IVS Solutions, Germany), and shape analysis was performed by vector-based 3D tools (Comparison®, 3Dshape, Germany).

Results

Orbital volume of the unaffected side ranged from 26.6 ml ± 2.8 ml in male and 25.2 ml ± 2.6 ml in female (CT). Significant orbital enlargement was found in orbital fractures with involvement of the posterior third of the orbital floor and in comminuted fracture pattern. Reconstructed orbital volume ranged from 26.9 ± 2.7 ml in male and 24.26 ± 2.5 ml in female (CBCT). 3D Analysis of the color mapping showed minor deviations compared to the mirrored unaffected side.

Conclusion

Measurements demonstrate that even in comminuted orbital fractures true-to-original reconstruction is feasible.

Optic nerve monitoring

Orbital and anterior skull base surgery is generally performed close to the prechiasmatic visual pathway, and clear strategies for detecting and handling visual pathway damage are essential. To overcome the common problem of a missed clinical examination because of an uncooperative or unresponsive patient, flash visual evoked potentials and electroretinograms should be used. These electrophysiologic examination techniques can provide evidence of intact, pathologic, or absent conductivity of the visual pathway when clinical assessment is not feasible. Visual evoked potentials and electroretinograms are thus essential diagnostic procedures not only for primary diagnosis but also for intraoperative evaluation. A decision for or against treatment of a visual pathway injury has to be made as fast as possible due to the enormous importance of the time elapsed with such injuries; this can be achieved additionally using multislice spiral computed tomography. The first-line conservative treatment of choice for such injuries is megadose methylprednisolone therapy. Surgery is used to decompress the orbital compartment by exposure of the intracanalicular part of the optic nerve in the case of optic canal compression. Modern craniomaxillofacial surgery requires detailed consideration of the diagnosis and treatment of traumatic visual pathway damage with the ultimate goal of preserving visual acuity.

Assessment of cervical lymph node metastasis for therapeutic decision-making in squamous cell carcinoma of buccal mucosa: a prospective clinical analysis

Background

Cervical metastasis has a tremendous impact on the prognosis in patients with carcinomas of the head and neck and the frequency of such spread is greater than 20% for most squamous cell carcinomas. With emerging evidence, focus is shifting to conservative neck procedures aimed at achieving good shoulder function without compromising oncologic safety. The purpose of this study was to analyze the pattern of nodal metastasis in patients presenting with squamous cell carcinoma of buccal mucosa.

Materials and methods

This was a prospective clinical analysis of patients who were histologically diagnosed with squamous cell carcinoma of the buccal cavity and clinically N1 and had not received treatment anywhere else. Patients were analyzed for age and sex distribution, tumor staging, location, and metastasis.

Results

The incidence of metastatic lymph node in T4 (n=44) was the highest, that is, level I was 100% (44/44), level II was 43.18% (19/44), level III was 15.90% (7/44), and level IV was 4.5% (2/44). Level V was free of metastasis. Among T3 (n=10) lesions, incidence of metastasis in level I was 100% (10/10), level II was 20% (2/10), and level III, IV, and V were free of metastasis. Among T2 (n=6) lesions, incidence of lymph node metastasis in level I was 100% (6/6) and all other levels of lymph nodes were found free of metastasis.

Conclusion

Lymphatic spread from carcinoma of the buccal mucosa is low. Involvement of level IV is seen in only 3% of patients. A more conservative approach to the neck in patients with carcinoma of the buccal mucosa is recommended.

[Reconstruction of complex midfacial defects with individualized titanium implants]

BACKGROUND

Loss of hard and soft tissue structures of the midface due to resection or trauma is associated with substancial functional and aesthetic deficits. Besides reconstruction of bony contours for preservation of orbit position and facial symmetry, reconstruction often requires simultaneous transplantation of soft tissue flaps for separation of nasal and oral cavities and refilling of soft tissue volume deficits.

PATIENTS AND METHODS

A well-established procedure of our institution will be demonstrated in 10 exemplary patients, in which titanium meshes are customized for individual defect situations using computer-assisted techniques in combination with soft tissue transfer if required.

RESULTS

According to our experience, this procedure provides satisfactory results in functional as well as in aesthetic respects. Especially in patients with loss of bony structures of the orbit and preservation of orbital contents, this procedure forms optimal preconditions for prevention of enophthalmos and diplopia by preservation of the original orbital volume.

CONCLUSION

Individualized titanium implants should be used more frequently in clinical routine for reconstruction of complex midfacial defects.

Increase in periosteal angiogenesis through heat shock conditioning

Objective

It is widely known that stress conditioning can protect microcirculation and induce the release of vasoactive factors for a period of several hours. Little, however, is known about the long-term effects of stress conditioning on microcirculation, especially on the microcirculation of the periosteum of the calvaria. For this reason, we used intravital fluorescence microscopy to investigate the effects of heat shock priming on the microcirculation of the periosteum over a period of several days.

Methods

Fifty-two Lewis rats were randomized into eight groups. Six groups underwent heat shock priming of the periosteum of the calvaria at 42.5°C, two of them (n = 8) for 15 minutes, two (n = 8) for 25 minutes and two (n = 8) for 35 minutes. After 24 hours, a periosteal chamber was implanted into the heads of the animals of one of each of the two groups mentioned above. Microcirculation and inflammatory responses were studied repeatedly over a period of 14 days using intravital fluorescence microscopy. The expression of heat shock protein (HSP) 70 was examined by immunohistochemistry in three further groups 24 hours after a 15-minute (n = 5), a 25-minute (n = 5) or a 35-minute (n = 5) heat shock treatment. Two groups that did not undergo priming were used as controls. One control group (n = 8) was investigated by intravital microscopy and the other (n = 5) by immunohistochemistry.

Results

During the entire observation period of 14 days, the periosteal chambers revealed physiological microcirculation of the periosteum of the calvaria without perfusion failures. A significant (p < 0.05) and continuous increase in functional capillary density was noted from day 5 to day 14 after 25-minute heat shock priming. Whereas a 15-minute exposure did not lead to an increase in functional capillary density, 35-minute priming caused a significant but reversible perfusion failure in capillaries. Non-perfused capillaries in the 35-minute treatment group were reperfused by day 10. Immunohistochemistry demonstrated an increase in cytoprotective HSP70 expression in the periosteum after a 15-minute and a 35-minute heat shock pretreatment when compared with the control group. The level of HSP70 expression that was measured in the periosteum after 25 minutes of treatment was significantly higher than the levels observed after 15 or 35 minutes of heat shock exposure.

Conclusion

A few days after heat shock priming over an appropriate period of time, a continuous increase in functional capillary density is seen in the periosteum of the calvaria. This increase in perfusion appears to be the result of the induction of angiogenesis.

Pre-operative planning for mandibular reconstruction - a full digital planning workflow resulting in a patient specific reconstruction

Objectives

Reconstruction of large mandiblular defects following ablative oncologic surgery could be done by using vascularized bone transfer or, more often, primarily with simultaneous or delayed bone grafting, using load bearing reconstruction plates. Bending of these reconstruction plates is typically directed along the outer contour of the original mandible. Simultaneously or in a second operation vascularized or non-vascularized bone is fixed to the reconstruction plate. However, the prosthodontic-driven backward planning to ease bony reconstruction of the mandible in terms of dental rehabilitation using implant-retained overdentures might be an eligible solution. The purpose of this work was to develop, establish and clinically evaluate a novel 3D planning procedure for mandibular reconstruction.

Materials and methods

Three patients with tumors involving the mandible, which included squamous cell carcinoma in the floor of the mouth and keratocystic odontogenic tumor, were treated surgically by hemimandibulectomy.

Results

In primary alloplastic mandible reconstruction, shape and size of the reconstruction plate could be predefined and prebent prior to surgery.

Clinical relevance

This study provides modern treatment strategies for mandibular reconstruction.

Orbital metastases as first sign of metastatic spread in breast cancer: case report and review of the literature

Background

Intraorbital metastases of breast cancer is rare with only 3-10% of all ocular metastases. We report a case of orbital metastases as first sign of systemic metastatic spread in a female patient with breast cancer.

Methods

The patient had been diagnosed with breast cancer 3 years before. Her present complain was local pain, diplopia and periorbital swelling. A CT scan revealed extensive bony destruction of the orbital roof/anterior skull base. Bone scintigraphy demonstrated additional uptake at the level of the skull base, cervical spine, ilium and ribs suggesting metastatic spread to the skeleton. A navigation-assisted intraorbital biopsy from the orbital roof revealed a metastasis of breast cancer. With the confirmed diagnosis of metastatic breast cancer the patient was refered to the oncologist for further tumor staging. As further treatment she received systemic palliative chemotherapy in addition to intravenous treatment with bisphosphonates.

Conclusion

In patients with a previous history of breast cancer who complain even of mild ophthalmologic symptoms such as local pain, periorbital edema, it is important to consider ocular or orbital metastatic disease. Adequate 3D-Imaging followed by a biopsy will usually confirm the diagnosis.

Endoscope-assisted transoral reduction and internal fixation versus closed treatment of mandibular condylar process fractures--a prospective double-center study

PURPOSE

The aim of this international AO-study was to compare the functional outcome after open versus closed treatment of mandibular condylar neck fractures.

PATIENTS AND METHODS

A prospective comparative study with two follow-ups (FU) at 8-12 weeks and 1 year was undertaken in two clinics, which exclusively privileged either surgical or conservative treatment due to different therapeutic agendas. Patients from clinic 1 (ENDO group) received endoscope-assisted transoral open reduction and internal fixation, whereas patients from clinic 2 (CONS group) were treated conservatively without surgery. Patients with unilateral condylar neck fractures showing one or more of the following conditions were included: displacement of the condyle with an inclination >30° and/or severe functional impairment such as malocclusion or open bite, with or without dislocation of the condylar fragment; severe pain upon palpation or movement, and/or vertical shortening of the ascending ramus. High or intracapsular condylar neck fractures were excluded.

RESULTS

75 patients (44 CONS and 31 ENDO patients) with condylar neck fractures were included in this study. The Asymmetric Helkimo Dysfunction Score (A-HDS) was slightly lower in the CONS group than in the ENDO group at the 8-12-week FU, corresponding to better function on the short-term. At the 1-year FU, however, there were slightly better values in the ENDO group. For the Clinical Dysfunction Index (Di) and the Anamnestic Dysfunction Index (Ai), CONS patients had a better outcome than ENDO patients at the 8-12 week FU, ie, a higher proportion of ENDO patients had severe symptoms due to the operative trauma. Yet these symptoms improved by one year, finishing with a significant higher proportion of symptom-free patients in the ENDO group. In addition, these patients had better values for the Index for Occlusion and Articulation Disturbance (Oi) at both FU examinations, ie, the proportion of patients without any occlusal disturbances was significantly higher in the ENDO group. On average, the duration of postoperative maxillo-mandibular fixation (MMF) was 3 times longer for the CONS group than for the ENDO group (33 vs. 11 days).

CONCLUSION

Both treatment options may yield acceptable results for displaced condylar neck fractures. Especially in patients with severe malocclusion directly after trauma, however, endoscope-assisted transoral open reduction and fixation seems to be the appropriate treatment for prevention of occlusal disturbances during FU.

Reconstruction of mandibular defects - clinical retrospective research over a 10-year period -

Backround

Functional and cosmetic defects in the maxillofacial region are caused by various ailments and these defects are addressed according to their need. Simplicity of procedure, intact facial function and esthetic outcome with the least possible donor site morbidity are the minimum requirements of a good reconstruction. Oro-mandibular reconstruction, although a challenge for the head and neck reconstructive surgeon, is now reliable and highly successful with excellent long-term functional and aesthetic outcomes with the use of autogenous bone grafts. Reconstruction of trauma- or mandibular oncologic defects with bony free flaps is considered the gold standard. However the the optimal reconstruction of mandibular defects is still controversial in regards to reconstructive options which include the donor site selection and the timing of surgery. The purpose of this study was to determine the outcome of different osseous reconstruction options using autogenous bone grafts for mandibular reconstructions.

Methods

This study was carried out on 178 patients with mandibular bone defects. They were reconstructed with autogenous bone grafts from different donor sites. At post operative visits they were evaluated for functional and cosmetic results.

Results

The success rate found in this study was around 90%. Only 7.6% of the cases showed poor results regarding facial contours and mouth opening. All other patients were satisfied with their cosmesis and mouth opening at the recipient sites was in the normal range during last follow-up visits. Donor sites were primarily closed in all cases and there was no hypertrophic scar.

Conclusion

Based on this study, autogenous bone grafts are a reliable treatment modality for the reconstruction of mandibular bone defects with predictable aesthetic and functional outcomes. As the free vascularized fibular flap has the least resorption and failure rate, it should be the first choice for most cases of mandiblular reconstruction.

Effects of VEGF loading on scaffold-confined vascularization

Adequate vascularization of tissue-engineered constructs remains a major challenge in bone grafting. In view of this, we loaded ß-tricalcium-phosphate (ß-TCP) and porous poly(L-lactide-co-glycolide) (PLGA) scaffolds via collagen coating with vascular endothelial growth factor (VEGF) and studied whether the VEGF loading improves scaffold angiogenesis and vascularization. Dorsal skinfold chambers were implanted into 48 balb/c mice, which were assigned to 6 groups (n = 8 each). Uncoated (controls), collagen-coated, and additionally VEGF-loaded PLGA and ß-TCP scaffolds were inserted into the chambers. Angiogenesis, neovascularization, and leukocyte-endothelial cell interaction were analyzed repeatedly during a 14-day observation period using intravital fluorescence microscopy. Furthermore, VEGF release from PLGA und ß-TCP scaffolds was studied by ELISA. Micromorphology was studied from histological specimens. Unloaded ß-TCP scaffolds showed an accelerated and increased angiogenic response when compared with unloaded PLGA scaffolds. In vitro, PLGA released significantly higher amounts of VEGF compared with ß-TCP at the first two days resulting in a rapid drop of the released amount at the following days up to day 7 where the VEGF release was negligible. Nonetheless, in vivo VEGF loading increased neovascularization, especially in ß-TCP scaffolds. This increased vascularization was associated with a temporary leukocytic response with pronounced leukocyte-endothelial cell interaction at days 3 and 6. Histology revealed adequate host tissue response and engraftment of both ß-TCP and PLGA scaffolds. Our study demonstrates that ß-TCP scaffolds offer more suitable conditions for vascularization than PLGA scaffolds, in particular if they are loaded with VEGF.

Prefabrication of vascularized bioartificial bone grafts in vivo for segmental mandibular reconstruction: experimental pilot study in sheep and first clinical application

The key elements for bioartificial bone formation in 3D matrices are large numbers of osteogenic cells and supplies of oxygen and nutrition. Vascularization becomes more important with the increasing size and complexity of seeded scaffolds required for clinical application in reconstructive craniomaxillofacial surgery. Prefabrication of vascularized bioartificial bone grafts in vivo might be an alternative to in vitro tissue engineering techniques. Two cylindrical beta-TCP-scaffolds (25 mm long) were intraoperatively filled with autogenous bone marrow from the iliac crest for cell loading and implanted into the latissimus dorsi muscle in 12 sheep. To determine the effect of axial perfusion, one scaffold in each sheep was surgically supplied with a central vascular bundle. Sheep were killed 3 months after surgery. Histomorphometric analysis showed autogenous bone marrow from the iliac crest was an effective source of osteogenic cells and growth factors, inducing considerable ectopic bone growth in all implanted scaffolds. Bone growth, ceramic resorption and angiogenesis increased significantly with axial perfusion. The results encourage the application of prefabricated bioartificial bone for segmental mandibular reconstruction in man. In clinical practice, vascularized bioartificial bone grafts could change the principles of bone transplantation with minimal donor site morbidity and no shape or volume limitations.

[Necrotizing sialometaplasia: diagnosis of a rare entity]

A differential diagnosis of an ulcer on the hard palate must consider a wide variety of diseases and conditions, among them rare entities such as necrotizing sialometaplasia. We report the case of a patient who presented with a painful ulcer on the hard palate. A biopsy taken at the initial presentation of the patient revealed a diagnosis of necrotizing sialometaplasia. Histology showed foci of eosinophilic granulocytes with lobular infarction or necrosis, bland-appearing nuclear morphology of squamous cells, simultaneous metaplasia of ducts and mucous acini. The ulcer resolved spontaneously within seven weeks and required no specific treatment. The case presented here shows that early diagnosis of necrotizing sialometaplasia is important in order to prevent unnecessary treatment.