Dependence of odontogenic abscess on meteorological parameters: truth or myth?

OBJECTIVES: It is still a common belief among dental practitioners that odontogenic abscesses are somehow linked to meteorological parameters. We investigated the influence of different meteorological parameters on the type of surgical abscess treatment (intra- versus extraoral incision) as a measure of the weather-dependent severity of infection. MATERIALS AND METHODS: In this retrospective cohort study, we analyzed 841 patients who presented at our outpatient clinic with an odontogenic abscess between 2004 and 2013. RESULTS: We found no statistical dependence between intra- versus extraoral abscess incision with regard to temperature, atmospheric pressure, or relative air humidity. The annual distribution of abscesses was even, and the number of abscesses with greater or lesser mean values of each meteorological parameter did not differ significantly. CONCLUSIONS: Our results showed no statistical relationship between meteorological parameters and intra- or extraoral abscess incisions. CLINICAL RELEVANCE: Our analysis supports the assumption that the theorized relationship between odontogenic abscesses and meteorological parameters remains a myth.

Toll-like receptor 2/6-dependent stimulation of mesenchymal stem cells promotes angiogenesis by paracrine factors.

Reconstruction of critical size bone defects represents a major challenge in orthopaedic surgery. Insufficient angiogenesis is a limiting factor for engraftment of large-scale tissue transplants. Transplantation or stimulation of local mesenchymal stem cells (MSCs) represents a potential solution to enhance angiogenesis. We recently identified angiogenic properties for the Toll-like receptor (TLR) 2/6 agonist MALP-2 and now investigated if MALP-2 could be used to stimulate MSCs in order to promote angiogenesis in vitro and in vivo. Human MSCs from the bone marrow of healthy subjects were isolated, cultured and expanded in vitro and were shown to be positive for mesenchymal stem cells markers as well as for the MALP-2 receptors TLR2 and TLR6. MALP-2 directly enhanced migration but not proliferation of human MSCs. Conditioned medium from MALP-2 stimulated MSCs significantly increased proliferation, migration and tube formation of endothelial cells. Analysis of the conditioned medium from MSCs revealed that MALP-2 stimulation enhanced the secretion of several chemokines and growth factors including vascular endothelial growth factors (VEGF) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Finally, we studied MALP-2 effects on MSCs in a sheep model of tissue engineering in vivo. Therefore, MSCs were isolated from the iliac crest of black head sheep and co-cultivated with MALP-2 ex vivo. Implantation of autologous MSCs within a scaffold cylinder into the M. latissimus dorsi significantly enhanced vessel density of these constructs after 6 months. We here present the first evidence that TLR2/6-dependent stimulation of MSCs promotes angiogenesis in vitro and in vivo offering a novel strategy for therapeutic angiogenesis, e.g., for tissue engineering of bone.

Paediatric gingival extra-axial chordoma: an extremely rare entity.

Extra-axial chordomas are rare malignant tumours. As a subcategory of axial chordomas, these tumours arise outside the axial skeleton. This report describes the case of a 13-year-old male patient with a gingival mass in the left upper jaw, who was referred to Hannover Medical School with a preliminary diagnosis of a calcifying epithelial odontogenic tumour (CEOT). Pathological examination of the enucleated tumour led to the final diagnosis of a chordoma. Thereafter, a stepwise radical resection was performed with the aim of complete resection of the tumour with wide safety margins. The main tumour mass was found to be located on the maxillary gingiva, with focal infiltration into the maxillary bone. Following resection, reconstruction was performed with a free latissimus dorsi flap. Follow-up after 1 year revealed no signs of recurrence or metastasis. This case highlights that although extremely rare, extra-axial chordoma may occur at sites distant from the midline and as such must be included in the differential diagnosis of bone and soft tissue tumours in the maxillofacial region.

Reduction in perioperative blood loss using ultrasound-activated scissors during tumour surgery.

The aim of this study was to compare the effectiveness of Harmonic Focus+ scissors with the conventional surgical method regarding surgical blood loss and transfusion of blood products in the surgical treatment of head and neck tumours. In a retrospective study, the intraoperative blood loss, number of units of transfusion products given, operating time, and inpatient length of stay of 74 patients with squamous cell carcinoma were compared. Patients who underwent classic tumour surgery were compared with a group treated with Harmonic Focus+ scissors. A significantly lower intraoperative blood loss (496.15⬰ml vs 1096.0⬰ml, respectively; P⬰=⬰0.002) and shorter operation time (436.89 minutes vs 493.13 minutes, respectively; P⬰=⬰0.030) were achieved using the Harmonic Focus+ scissors when compared to the classic tumour surgery. Additionally, fewer units of blood products needed to be transfused (administration of red cell concentrates, P⬰<⬰0.001) and the length of stay in the intensive care unit was shorter for patients treated with the Harmonic Focus+ scissors (P⬰=⬰0.009). The study results indicate that the use of Harmonic Focus+ scissors during surgery for cancer of the oral cavity and pharynx is a safe and cost-effective method. This is of paramount importance during a pandemic when medical resources are scarce, including access to blood reserves.

Quantitative analysis of soft tissue sagging after lateral midface fractures: A 10-year retrospective study.

BACKGROUND: Lateral midface fractures occasionally require open reduction and internal fixation to restore function and facial symmetry. However, some patients retain facial asymmetry despite undergoing surgery due to hard tissue displacement or soft tissue sagging. This study aimed to determine the influence of soft tissue sagging on the postoperative facial symmetry. METHODS: We examined the medical records of 590 patients who underwent planned plate removal after lateral midface or zygomatic bone fractures. After applying the inclusion and exclusion criteria, we analyzed 106 cases of lateral midface fractures for hard tissue displacement and soft tissue sagging using pre- and postoperative radiological imaging and postoperative face scanning. RESULTS: We observed significantly larger soft tissue sagging (p < 0.001) and hard tissue displacement (p = 0.006) on the fractured side than on the non-fractured side. There was no correlation between differences in the soft tissue sagging and those in the hard tissue displacement (|rho|=0). Linear regression analysis showed no statistical influence of sex or age group on the soft tissue sagging and hard tissue displacement. CONCLUSION: Therefore, we recommend treating soft tissue sagging as a discrete aspect of midfacial fracture treatment to achieve optimal postoperative facial symmetry. From a clinical perspective, we recommend better soft tissue management during open fracture treatment than focusing mainly on the reduction of bony hard tissues.

Intraoperative real-time navigation and intraoperative three-dimensional imaging for patient-specific total temporomandibular joint replacement.

Customized solutions for replacement of the temporomandibular joint (TMJ) along with surgical guides enable precise and fast transfer of the virtual plan to the patient. However, these guides lack information on screw vectors and length, and well-defined borders for bony resections towards the medial skull base. This retrospective study was performed to investigate the feasibility and benefit of real-time navigation and intraoperative three-dimensional imaging during total TMJ replacement (TJR), as well as patient clinical outcomes. Between 2016 and 2020, 26 customized prostheses were implanted in 21 patients either with or without real-time navigation and instrument tracking. The clinical, surgical, radiological, and navigational data were analysed. The accuracy of navigation registration with instrument tracking, precision of screw insertion, and implant and screw positions were analysed by fusion of the virtual plan and surgical outcome. Real-time navigation aided orientation during lateral skull base dissection and resection. However, the results of real-time navigation-aided drilling were inconclusive regarding vector and length control. At a mean 15.3±3.0 months of follow-up, average mouth opening had improved from 21.69±2.80mm to 36.40±1.25mm; the average pain score decreased from 6.18±0.74 to 1.06±0.52. Thus, intraoperative real-time navigation for TJR assists lateral skull base dissection and resection.

Intraorbital volume augmentation with patient-specific titanium spacers.

INTRODUCTION: Estimating the needed overcorrection of the globe position depends mainly on the clinical evaluation during an operation to correct hypo- and enophthalmos in primary and secondary orbital reconstruction for which several autogenous and alloplastic materials can be used. However, donor-side morbidity and time loss in obtaining autogenous materials are problematic. We developed a novel technique using titanium spacers that minimizes these factors. METHODS: We conducted a retrospective study of all patients treated with titanium spacers for orbital reconstruction at our department between 2014 and 2018. The primary predictor variable was a change in the deformity. The outcome variable was visual appearance, measured on a scale from 0 to 3. Other study variables included binocular vision and complications. Descriptive statistics and the Mann-Whitney rank sum test were used to check for statistical significances. The P-value was set at 0.05. RESULTS: The study sample was composed of 29 patients. Postoperative results were comparable to the results of other methods described in the literature with approximately 25% of our patients experiencing residual visual deformity. The overall visual deformity decreased in our study, and visual appearance improved significantly (P<0.001). Complication rates were also comparable to those reported by other investigators. CONCLUSION: Our method is an effective and safe procedure for correcting hypo- and enophthalmos while minimizing donor-side morbidity and treatment time.

Oral health-related quality of life in tumour patients treated with patient-specific dental implants.

Dental rehabilitation after surgically acquired bone deficiency related to tumour treatment remains a challenge. The insertion of patient-specific implants geared to the contour of the remaining bone is a feasible method of supporting fixed or removable dentures. As oral health-related quality of life (OHRQoL) is of great interest in these cases, 12 individuals treated with patient-specific implants for severe bone deficiency were surveyed and their Oral Health Impact Profile (OHIP) scores after dental rehabilitation were evaluated. The OHIP-G53 questionnaire was used to measure overall treatment outcomes. The distribution of OHIP sum-scores for participants treated with patient-specific implants was almost homogeneous when compared to those cited in the literature for patients treated with conventional dental implants. OHIP items related to functional impairment and physical pain showed the highest scores (occurring occasionally), and financial loss related to treatment was frequently stated. Moreover, higher scores were detected in almost all OHIP dimensions for participants with patient-specific implant-supported removable dentures. Conversely, those treated with patient-specific dental implants and fixed dentures showed lower psychosocial impact scores and equal or superior OHRQoL. Hence, patient-specific dental implants, especially combined with fixed dentures, can lead to a positive OHRQoL in patients with severe bone deficiencies related to tumour therapy.

Reality or wishful thinking: do bicycle helmets prevent facial injuries?

Standard bicycle helmets are designed to protect the cranial vault. Numerous studies have demonstrated the beneficial effect of standard bicycle helmets on craniocerebral trauma, but their protective effect on facial injuries remains unclear. Therefore, this study used data obtained by an accident research unit to investigate the protective effect of standard bicycle helmets on facial injuries. A total of 31,634 bicycle accidents were registered between 1999 and 2015; of these, 7004 met the study requirements. Demographic characteristics, technical information (relative collision speed, collision type, collision partner, helmet use), and clinical data (injury type) relating to these accidents were analyzed. Of all affected cyclists, 1005 (14.3%) had a facial injury (fracture and/or soft tissue injury). Bicycle helmets were worn in 11.8% of accidents. Of these, 75.4% involved males and 24.6% involved females. The bicycle helmet did not protect against facial injuries. Furthermore, sex and the type of collision partner were found to be risk factors for facial injuries. In the future, helmet designs should be modified to improve facial protection, and better education should be provided to the public regarding the benefits of bicycle helmets.

Scapula pre-augmentation in sheep with polycaprolactone tricalcium phosphate scaffolds.

A scapula free flap is a commonly used method to reconstruct intraoral defects of the mandible and maxilla. Despite its clear advantages, it shows some deficiencies concerning the amount and shape of the available bone, especially with respect to later implant placement. To overcome these limitations, we pre-augmented the scapula prior to a potential flap-raising procedure with polycaprolactone (PCL) tricalcium phosphate (TCP) scaffolds in a sheep model. In our study, the scapula angle was augmented with a block of PCL-TCP in three adult sheep. After 6 months, the amount of newly formed bone and scaffold degradation were evaluated using cone-beam computed tomography scans and histomorphometric analysis. All animals survived the study and showed no problems in the augmented regions. The scaffolds were attached firmly to the scapula and showed a bonelike consistency. A fair amount of the scaffold material was degraded and replaced by vital bone. Our method seems to be a valid approach to pre-augment the scapula in sheep. In further experiments, it will be interesting to determine whether it is possible to transplant a modified scapula flap to an intraoral defect site.

Prelamination of the latissimus dorsi flap for reconstruction in head and neck surgery.

Free microsurgical tissue transfer of the latissimus dorsi flap may be indicated for the restoration of intra- and extraoral defects, especially when a large-sized skin island flap is required. In many cases, use of the latissimus dorsi flap for coverage of large-sized intraoral defects results in bulkiness due to the proportion of subcutaneous fat. Prelamination of free flaps appears to be a promising technique to overcome this flap bulkiness. This modification in flap design could improve the postoperative functional outcome, as well as reduce donor site morbidity. This article presents four novel clinical cases, in which the patients underwent prelamination of the latissimus dorsi flap with local skin grafts during oral cancer treatment in order to reduce the thickness of the free flap and allow tension-free primary closure of the donor site. These attempts successfully covered large-sized intraoral defects, achieving good functional outcomes with minimal donor site morbidity.

Modified lateral orbital wall decompression in Graves' orbitopathy using computer-assisted planning.

Graves' orbitopathy, a condition seen in the autoimmune syndrome Graves' disease, affects the fatty tissue and muscles inside the orbit. Graves' orbitopathy is associated with increasing exophthalmos and sometimes leads to compressive dysthyroid optic neuropathy, resulting in progressive vision loss. Dysthyroid compressive optic neuropathy, functional problems, and cosmetic problems are the main indications for surgical decompression of the orbit, especially if conservative treatment has not led to a reduction in symptoms. Many surgical techniques are described in the literature. This article presents a modification of the lateral orbital wall osteotomy, involving the rotation and reduction of the osteotomized bone segment using preoperative planning, intraoperative computed navigation, and piezoelectric surgery. This new method combines the advantages of different techniques and appears to be a valid approach to the treatment of severe cases of Graves' orbitopathy.

In vivo tissue engineered bone versus autologous bone: stability and structure.

This pilot study investigated the biomechanical properties of prefabricated, vascularized bioartificial bone grafts, which may provide an alternative bone source for the restoration of segmental osseous defects. Vascularized bioartificial bone grafts comprise an artificial customized scaffold made of beta-tricalcium phosphate. Bone formation along the prefabricated scaffold is induced by autogenous cancellous bone. Vascularization of the bone graft is provided by the host's vascular system. Within 6 months, a mammalian bioreactor (sheep were used in the present study) creates heterotopic vascularized bioartificial bone grafts of a predetermined anatomical shape, which can be harvested for reconstructing osseous defects. The bioartificial bone grafts in this study contained up to 25% bone tissue, as shown by histomorphometric analysis and computed tomography. Moreover, unconfined compression tests revealed that the constructs had mechanical characteristics similar to those of ovine cancellous bone. Therefore, this method could be applied to generate vascularized prefabricated bone substitutes for critical-size defects.

Piezoelectric surgery and navigation: a safe approach for complex cases of Eagle syndrome.

Eagle syndrome was first described by Eagle in 1937. It is associated with an elongated styloid process and/or calcification of the stylohyoid ligament, mainly resulting in pain in the orofacial region. The treatment of Eagle syndrome includes conservative treatment with physical therapy supported by medication, or surgical removal of the styloid process. Two different surgical approaches are described in the literature: the transoral and transcervical approaches. Both have their limitations and specific intraoperative risks. A modification of the transcervical approach that adds an extra security measure to the treatment of complex cases of Eagle syndrome is presented herein. The styloid process was removed by combining piezoelectric surgery, preoperative digital planning, and surgical navigation. No complication was noted, and the patient recovered quickly after surgery. A follow-up visit 2 months later showed no remaining symptoms of Eagle syndrome on the treated side. Therefore, digital planning and surgical navigation could add valuable safety measures to the treatment of complex cases of Eagle syndrome.

[Prefabrication of vascularized facial bones]. / Präfabrikation vaskularisierter Gesichtsknochen.

Critical size defects in the craniomaxillofacial region often result from ablative tumor surgery, inflammation and posttraumatic deformities. To date, autologous bone grafts are still the gold standard for the reconstruction of these defects; however, they are frequently associated with severe donor site morbidity as well as functional and aesthetic compromises. In this context various resorbable and non-resorbable bone replacement materials have been developed and intensively investigated. Particularly in critical size defects these materials fail due to their lack of osteogenic potential and endogenous vascularization. The combination of alloplastic osteoconductive scaffolds, osteogenic cells, and axial prevascularization in bioartificial bone grafts might present an innovative approach for the microsurgical reconstruction of critical size defects.

Heterotopic bone formation in the musculus latissimus dorsi of sheep using ß-tricalcium phosphate scaffolds: evaluation of an extended prefabrication time on bone formation and matrix degeneration.

We previously generated viable heterotopic bone in living animals and found that 3 months of intrinsic vascularization improved bone formation and matrix degeneration. In this study, we varied the pre-vascularization time to determine its effects on the kinetics of bone formation and ceramic degradation. Two 25-mm-long cylindrical ß-tricalcium phosphate scaffolds were filled intraoperatively with autogenous iliac crest bone marrow and implanted in the latissimus dorsi muscle in six sheep. To examine the effect of axial perfusion, one scaffold was surgically implanted with (group C) or without (group D) a central vascular bundle. All animals were sacrificed 6 months postoperatively and histomorphometric measurements were compared to previous results. All implanted scaffolds exhibited ectopic bone growth. However, bone growth was not significantly different between the 3-month (group A, 0.191±0.097 vs. group C, 0.237±0.075; P=0.345) and 6-month (group B, 0.303±0.105 vs. group D, 0.365±0.258; P=0.549) pre-vascularization durations, regardless of vessel supply; early differences between surgically and extrinsically vascularized constructs disappeared after 6 months. Here, we describe a reliable procedure for generating ectopic bone in vivo. A 3-month pre-vascularization duration appears sufficient and ceramic degradation proceeds in accordance with bone generation, supporting the hypothesis of cell-mediated resorption.

[Prefabrication of bone transplants]. / Präfabrikation von Knochentransplantaten.

Prefabrication of bone transplants is a promising option for large defects of the long bones, especially if there is compromised vascularization of the defect. This is especially true for postinfection bone defects and other types of atrophic nonunion. The generation of a foreign body membrane (Masquelet's technique) has been investigated in order to ameliorate the response of the host tissue surrounding the defect. In an experimental animal study, a blood vessel within a bone construct could be used to generate customized, vascularized osteogenic constructs that can be used to treat large bone defects in the future.

En bloc prefabrication of vascularized bioartificial bone grafts in sheep and complete workflow for custom-made transplants.

The aim of this pilot study was to determine, in a new experimental model, whether complex bioartificial monoblocs of relevant size and stability can be prefabricated in a defined three-dimensional design, in which the latissimus dorsi muscle serves as a natural bioreactor and the thoracodorsal vessel tree is prepared for axial construct perfusion. Eighteen sheep were included in the study, with six animals in each of three experimental groups. Vitalization of the ß-tricalcium phosphate-based constructs was performed by direct application of unmodified osteogenic material from the iliac crest (group A), in vivo application of nucleated cell concentrate (NCC) from bone marrow aspirate (group B), and in vitro cultivation of bone marrow stromal cells (BMSC) in a perfusion bioreactor system (group C). The contours of the constructs were designed digitally and transferred onto the bioartificial bone grafts using a titanium cage, which was bent over a stereolithographic model of the defined subvolume intraoperatively. At the end of the prefabrication process, only the axial vascularized constructs of group A demonstrated vital bone formation with considerable stability. In groups B and C, the applied techniques were not able to induce ectopic bone formation. The presented computer-assisted workflow allows the prefabrication of custom-made bioartificial transplants.