Clinic-oriented injectable smart material for the treatment of diabetic wounds: Coordinating the release of GM-CSF and VEGF.

Chronic wounds are often caused by diabetes and present a challenging clinical problem due to vascular problems leading to ischemia. This inhibits proper wound healing by delaying inflammatory responses and angiogenesis. To address this problem, we have developed injectable particle-loaded hydrogels which sequentially release Granulocyte-macrophage- colony-stimulating-factor (GM-CSF) and Vascular endothelial growth factor (VEGF) encapsulated in polycaprolactone-lecithin-geleol mono-diglyceride hybrid particles. GM-CSF promotes inflammation, while VEGF facilitates angiogenesis. The hybrid particles (200-1000 nm) designed within the scope of the study can encapsulate the model proteins Bovine Serum Albumin 65 ± 5 % and Lysozyme 77 ± 10 % and can release stably for 21 days. In vivo tests and histological findings revealed that in the hydrogels containing GM-CSF/VEGF-loaded hybrid particles, wound depth decreased, inflammation phase increased, and fibrotic scar tissue decreased, while mature granulation tissue was formed on day 10. These findings confirm that the hybrid particles first initiate the inflammation phase by delivering GM-CSF, followed by VEGF, increasing the number of vascularization and thus increasing the healing rate of wounds. We emphasize the importance of multi-component and sequential release in wound healing and propose a unifying therapeutic strategy to sequentially deliver ligands targeting wound healing stages, which is very important in the treatment of the diabetic wounds.

A Case of Nasal Glial Heterotopia That Can Be Misdiagnosed as Storiform Patterned Sclerotic Fibroma/Collagenoma.

OBJECTIVE: Nasal glioma, also known as nasal glial heterotopia, is a rare tumor-like lesion that often affects newborns or infants with no hereditary predisposition. CASE REPORT: A 4-year-old child with a growth on the nasal dorsum since birth was diagnosed with nasal glial heterotopia/nasal glioma. The lesion showed a sclerotic fibroma/collagenoma-like storiform pattern with entrapped glial tissue that was S100 and GFAP positive. CONCLUSION: When a biopsy of the nasal dorsum demonstrates sclerotic microscopic findings with a storiform pattern, nasal glioma should be considered before making a diagnosis in the collagen-rich tissue spectrum (collagenoma or Gardner's fibroma), and an immunohistochemical panel should be requested to demonstrate the presence of an unrecognized light microscopically visible glial component.

Assessment of Ecotropic Viral Integration Site 2B (EVI2B) Gene in Juvenile Myelomonocytic Leukemia and Neurofibromatosis Type 1 NF1 Tumors.

Neurofibromatosis type 1 (NF1) is an autosomal dominant disease that affects the development and growth of various tissues. NF1 is a major risk factor for the development of malignancies, particularly malignant peripheral nerve sheath tumors, optic gliomas, and leukemia. NF1 encodes a neurofibromin. Three genes, EVI2A, EVI2B, and OMGP, are embedded within intron 27b of NF1. However, the function of these genes remains unclear. EVI2A and EVI2B encode for putative transmembrane proteins. Mouse homologs are associated with viral insertions involved in leukemia in mice. Mouse Evi2b has been identified as a direct target gene of C/EBPα, a transcription factor critical for myeloid differentiation. Also possible is that these genes are related to the leukemia observed in patients with NF1. These genes might act as modifiers of NF1 phenotypic variations. Therefore, we investigated the EVI2B gene in leukemia and NF1 tumors. We analyzed DNA from 10, 20, and 3 patients with NF1, leukemia, and NF1-leukemia, respectively, and six NF1 tumor tissues. DNA sequencing analysis was used to identify the viral integration sequence, and the protein amounts and EVI2B gene expression were analyzed by flow cytometry and quantitative real-time PCR techniques. The EVI2B gene expression was increased in cutaneous neurofibroma compared with the control both at the level of protein and mRNA. However, its expression in plexiform neurofibroma was decreased significantly at protein level and increased at mRNA level compare to control. Moreover, integration of 455 bases near the 3' end of the exon was detected. When this integrated sequence was blasted into the NCBI retroviral genome database, an 87% match with the HIV-1 virus envelope gene was obtained. These preliminary results show that EVI2B might be important in NF1 tumorigenesis and leukemia.

Surgical method for critical sized cranial defects in rat cranium.

Cranial tissue models are a widely used model to show the bone repair and the regeneration ability of candidate biomaterials for tissue engineering purposes. Until now, efficacy studies of different biomaterials for calvarial defect bone regeneration have been reported, generally in small animal models. This paper offers a versatile, reliable, and reproducible surgical method for creating a critical-sized cranial defect in rats including critical steps and tried-and-tested tips. The method proposed here,•Shows a general procedure for in vivo cranial models.•Provide an insight to restore bone tissue repair that may be used in combination with several tissue engineering strategies•Is a crucial technique that may guide in vivo bone tissue engineering.

Endovascular Treatment of Peripheral Arteriovenous Malformations (AVMs): Do Angiographic Outcomes Relate to the Quality of Life?

PURPOSE: Patients with arteriovenous malformations (AVMs) have a lower health-related quality of life (QoL) than the general population. QoL assessment of patients with peripheral AVMs after endovascular treatment is scarce in the literature. Radiologic and clinical outcomes are not always correlated in vascular malformation treatment. This study aimed to investigate the relationship between clinical outcomes, QoL, and angiographic outcomes. MATERIALS AND METHODS: Patients with peripheral AVM that underwent endovascular treatment between January 2009 and December 2021 in a single center were retrospectively evaluated. Patients' characteristics (age, sex), AVM characteristics (Schobinger classification, location, angiographic architecture), previous treatment, treatment characteristics (type of endovascular approach, embolizing agent and number of sessions), percentages of angiographic response, complications, and recurrence were evaluated. The angiographic architecture was evaluated according to the Yakes classification. The questionnaire was applied for evaluation of clinical response and QoL. Patients older than 12 years and those who can be contacted were included in clinical and QoL analysis. Clinical response was defined as improvement in the patient's most important pretreatment symptom. Treatment response was defined as clinical response plus >50% angiographic response. RESULTS: Eighty-six patients (41 males [47.7%], 45 females [52.3%]) were included in angiographic analysis. The mean age was 28.44±12.99 years (range=5-61). Forty-three patients (50%) had previous treatment. The median number of sessions was 2 (range 1-15, InterQuartile Range [IOR]=2). Sixty-one patients (30 males [49.2%], 31 females [50.8%]) were included in clinical analysis. The clinical response rate was 73.8%, 95% confidence interval (CI) [0.60, 0.84]. The treatment response rate was 45.9%, 95% CI [0.33, 0.59]. The complication rate was 8.2%. Before treatment, 48 patients (78.7%) reported a negative impact on their QoL. Thirty-three of 48 patients (68.8%) reported improvement on their QoL after treatment. Higher Schobinger stages were related to a negative impact on QoL before treatment (p<0.01). Yakes types were not related to QoL (p=0.065). Clinical response was related to improvement on QoL after treatment (p<0.01). Angiographic and treatment responses were not related to improved QoL after treatment (p=0.52 and p=0.055, respectively). CONCLUSION: Angiographic architecture and outcomes were not always reflected in QoL after endovascular treatment. CLINICAL IMPACT: This study's findings will help clinicians with what to focus on in AVM treatment and how to monitor patients with peripheral AVM after endovascular treatment. Rather than relying too much on the angiographic response, patients should be checked for symptoms and quality of life improvement. No clear data in the literature regarding the applicability of the Yakes Classification in patients with previous treatment. This study questioned the applicability of the Yakes Classification in patients with previous treatments. In this study, type 4 AVMs were more common in patients with previous treatment.

Clinical results of polidocanol sclerotherapy in venous malformation treatment: Patient-perceived improvement and satisfaction.

PURPOSE: This study evaluated the results of polidocanol sclerotherapy in the treatment of venous malformations (VM) including patient satisfaction, perceived improvement, and predictors of satisfaction. MATERIAL AND METHOD: Patients with VM that underwent polidocanol foam sclerotherapy between June 2013 and July 2021 in a single center were retrospectively evaluated. Patient demographics, VM, and treatment characteristics were analyzed. Patient-reported outcomes and satisfaction were analyzed with a questionnaire. RESULTS: This study included 232 (136, 58.6%, female) patients. The mean age was 24.49 ± 12.45 years (range 3-72). The clinical response rate was 82.3%. The rate of satisfaction was 82.3%, and 116 (50%) patients were significantly satisfied. There were no major complications. Clinical response and VM margin were related to satisfaction (p < 0.01, p = 0.012, respectively). Clinical response to pretreatment swelling was related to significant satisfaction (p = 0.02). CONCLUSION: Polidocanol sclerotherapy was safe and effective in VM treatment with high satisfaction and low complication rates.

Autologous Adipose-Derived Tissue Stromal Vascular Fraction (AD-tSVF) for Knee Osteoarthritis.

Adipose tissue contains adult mesenchymal stem cells that may modulate the metabolism when applied to other tissues. Stromal vascular fraction (SVF) can be isolated from adipose tissue mechanically and/or enzymatically. SVF was recently used to decrease the pain and improve the function of knee osteoarthritis (OA) patients. Primary and/or secondary OA causes inflammation and degeneration in joints, and regenerative approaches that may modify the natural course of the disease are limited. SVF may modulate inflammation and initiate regeneration in joint tissues by initiating a paracrine effect. Chemokines released from SVF may slow down degeneration and stimulate regeneration in joints. In this review, we overviewed articular joint cartilage structures and functions, OA, and macro-, micro-, and nano-fat isolation techniques. Mechanic and enzymatic SVF processing techniques were summarized. Clinical outcomes of adipose tissue derived tissue SVF (AD-tSVF) were evaluated. Medical devices that can mechanically isolate AD-tSVF were listed, and publications referring to such devices were summarized. Recent review manuscripts were also systematically evaluated and included. Transferring adipose tissues and cells has its roots in plastic, reconstructive, and aesthetic surgery. Micro- and nano-fat is also transferred to other organs and tissues to stimulate regeneration as it contains regenerative cells. Minimal manipulation of the adipose tissue is recently preferred to isolate the regenerative cells without disrupting them from their natural environment. The number of patients in the follow-up studies are recently increasing. The duration of follow up is also increasing with favorable outcomes from the short- to mid-term. There are however variations for mean age and the severity of knee OA patients between studies. Positive outcomes are related to the higher number of cells in the AD-tSVF. Repetition of injections and concomitant treatments such as combining the AD-tSVF with platelet rich plasma or hyaluronan are not solidified. Good results were obtained when combined with arthroscopic debridement and micro- or nano-fracture techniques for small-sized cartilage defects. The optimum pressure applied to the tissues and cells during filtration and purification of the AD-tSVF is not specified yet. Quantitative monitoring of articular joint cartilage regeneration by ultrasound, MR, and synovial fluid analysis as well as with second-look arthroscopy could improve our current knowledge on AD-tSVF treatment in knee OA. AD-tSVF isolation techniques and technologies have the potential to improve knee OA treatment. The duration of centrifugation, filtration, washing, and purification should however be standardized. Using gravity-only for isolation and filtration could be a reasonable approach to avoid possible complications of other methodologies.

Evaluation of histopathological margin and other recurrence parameters in basal cell carcinoma: A retrospective analysis of 8821 lesions.

Basal cell carcinoma (BCC) is the most common skin cancer. Removing the lesion with wide surgical margins and obtaining a microscopically intact margin is considered sufficient in the treatment of BCC. However, it may not always be possible to provide wide and intact margins in cosmetically and functionally important areas. Although recurrence rates after BCC excision vary among studies, the recurrence rate at 5 years is considered to be 2%. BCC subtype, perineural invasion, and close margin are important factors in recurrence. The aims of this study are to investigate the other factors associated with recurrence in BCC treatment and reveal the value of the "histopathological surgical margin" which can help in making the decision for re-excision. A statistically significant correlation is observed between the increase in tumour size and recurrence(p<0.05). The recurrence rate after excision with a histopathologic margin of 1 mm or less is 19%. This rate is found to be 8% in patients with a histopathological margin greater than 1 mm and 3 mm or less. Reticular dermis and deeper tissue invasion statistically increase the recurrence rate. Multiple excision and the presence of residual tumour in the re-excision sample also increase the recurrence rate. In conclusion, recurrence in BCC patients is affected by more than one parameter. We highly recommend re-excision in patients with a histopathological margin of 1 mm or less. In tumours with histopathological margins between 1 mm and 3 mm, the decision for re-excision or "wait-and-see" approach should be made according to the characteristics of the tumours and patients.

A novel ultrasound-guided minimally invasive technique for the treatment of extracapsular condylar fractures.

The aim of this study was to present a novel ultrasound-guided minimally invasive technique for the treatment of extracapsular condylar fractures and evaluate its long-term outcomes. Seven patients with isolated extracapsular condylar fractures with a noncomminuted proximal segment were included in this study. Ultrasound was used for identification of the position of the bone segments and intraoperative confirmation of appropriate reduction. Reduction of the displaced segments was performed using threaded K-wires under ultrasonographic visualization. The bone segments were stabilized using an adjustable modified external fixator designed by us, which allows manipulation of the segments in three planes intraoperatively and postoperatively, if needed. The functional outcomes of patients were evaluated. Patients treated with ultrasound-guided percutaneous reduction and external fixation achieved normal occlusion with satisfactory mouth opening (>35 mm) and had no pain during mandibular movements at long-term follow-up. None of the patients had any signs of facial nerve injury. Within the limitations of the study it seems that the poposed approch might be an alternative to the open approach in selected cases.

ALX-Related Frontonasal Dysplasias: Clinical Characteristics and Surgical Management.

AIM: The term frontonasal dysplasia (FND) represents a spectrum of anomalies and its genetics have not been well defined. Recently, the critical role of the aristaless-like homeobox (ALX) gene family on the craniofacial development has been discovered. In the present study, we aimed to propose a systematic surgical treatment plan for the ALX-related FNDs according to the genotypic classification as well as demonstrating their clinical characteristics to help surgeons diagnose the underlying pathology accurately. DESIGN: Single-institution retrospective. SETTING: Tertiary health care. PATIENTS AND METHODS: Eighty-nine FND cases were evaluated. Eight of them had ALX1-related FND3, 3 had ALX3-related FND1, and 2 had ALX4-related FND2. Phenotype characteristics of ALX-related FNDs were evaluated, and relevant surgical interventions were assessed. RESULTS: The ALX1-related FND3 phenotype is striking due to the involvement of the eyes in addition to the presence of hypertelorism, facial clefts, and nasal deformities. A widened philtrum and prominent philtral columns are remarkable features of the ALX3-related FND1, whereas the ALX4-related FND2 has more severe deformities: severe hypertelorism, brachycephaly, large parietal bone defects, broad nasal dorsum, and alopecia. Facial bipartition, box osteotomies, eyelid coloboma repair, cleft lip and palate repair, nasal reconstruction, and fronto-orbital advancement can be performed in ALX-related FNDs based on the characteristics of each subtype. CONCLUSIONS: This genetic classification system will help surgeon diagnose patients with FND with unique features and draw a roadmap for their treatment with a better surgical perspective.

Temporomandibular joint innervation: Anatomical study and clinical implications.

BACKGROUND: Temporomandibular disorders and related pain are commonly seen in clinical practice. Due to its recurrent nature, they adversely affect a patient's social life. Current knowledge on the temporomandibular joint (TMJ) innervation is debatable and insufficient to ensure optimal treatment for the underlying pathology. This study aimed to elucidate the pathophysiology of temporomandibular pain by revealing the TMJ innervation topography, its variations, and its relationships with the surrounding anatomical structures. This will aid in creating a guide for temporomandibular, infratemporal, and preauricular interventions. METHODS: A total of 20 cadaver half heads, 10 fresh frozen and 10 embalmed, were used. The TMJ nerves were dissected together with the surrounding anatomical structures. RESULTS: We showed that the TMJ is mainly innervated by the auriculotemporal nerve posteriorly, the masseteric nerve anteriorly, the posterior deep temporal nerve anteromedially, and the TMJ branch originating directly from the mandibular nerve medially, and that there are variations in these innervation pathways. Additionally, we emphasized how these nerves might be affected in certain clinical conditions based on their anatomical relationships and pathophysiological mechanisms. To our knowledge, this is the first study showing the existence of a branch of the mandibular nerve directly innervating the TMJ. CONCLUSION: In light of our findings, elucidating TMJ pain based on the anatomical characteristics of the region will allow precise treatment algorithms and better clinical outcomes in these patients. Based on this study, new clinical studies and interventions can be designed to reduce healthcare costs and alleviate the burden of temporomandibular disorders.

Biofabrication of Poly(glycerol sebacate) Scaffolds Functionalized with a Decellularized Bone Extracellular Matrix for Bone Tissue Engineering.

The microarchitecture of bone tissue engineering (BTE) scaffolds has been shown to have a direct effect on the osteogenesis of mesenchymal stem cells (MSCs) and bone tissue regeneration. Poly(glycerol sebacate) (PGS) is a promising polymer that can be tailored to have specific mechanical properties, as well as be used to create microenvironments that are relevant in the context of BTE applications. In this study, we utilized PGS elastomer for the fabrication of a biocompatible and bioactive scaffold for BTE, with tissue-specific cues and a suitable microstructure for the osteogenic lineage commitment of MSCs. In order to achieve this, the PGS was functionalized with a decellularized bone (deB) extracellular matrix (ECM) (14% and 28% by weight) to enhance its osteoinductive potential. Two different pore sizes were fabricated (small: 100-150 µm and large: 250-355 µm) to determine a preferred pore size for in vitro osteogenesis. The decellularized bone ECM functionalization of the PGS not only improved initial cell attachment and osteogenesis but also enhanced the mechanical strength of the scaffold by up to 165 kPa. Furthermore, the constructs were also successfully tailored with an enhanced degradation rate/pH change and wettability. The highest bone-inserted small-pore scaffold had a 12% endpoint weight loss, and the pH was measured at around 7.14. The in vitro osteogenic differentiation of the MSCs in the PGS-deB blends revealed a better lineage commitment of the small-pore-sized and 28% (w/w) bone-inserted scaffolds, as evidenced by calcium quantification, ALP expression, and alizarin red staining. This study demonstrates a suitable pore size and amount of decellularized bone ECM for osteoinduction via precisely tailored PGS elastomer BTE scaffolds.

Treatment of tumour tissue with radio-frequency hyperthermia (using antibody-carrying nanoparticles).

Intelligent inorganic nanoparticles were designed and produced for use in imaging and annihilating tumour cells by radio-frequency (RF) hyperthermia. Nanoparticles synthesised to provide RF hyperthermia must have magnetite properties. For this purpose, magnetite nanoparticles were first synthesised by the coprecipitation method (10-15 NM). These superparamagnetic nanoparticles were then covered with gold ions without losing their magnetic properties. In this step, gold ions are reduced around the magnetite nanoparticles. Surface modification of the gold-coated magnetic nanoparticles was performed in the next step. A self-assembled monolayer was created using cysteamine (2-aminoethanethiol) molecules, which have two different end groups (SH and NH2 ). These molecules react with the gold surface by SH groups. The NH2 groups give a positive charge to the nanoparticles. After that, a monoclonal antibody (Monoclonal Anti-N-CAM Clone NCAM-OB11) was immobilised by the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide method. Then, the antenna RF system (144.00015 MHz) was created for RF hyperthermia. The antibody-nanoparticle binding rate and cytotoxicity tests were followed by in vitro and in vivo experiments. As the main result, antibody-bound gold-coated magnetic nanoparticles were successfully connected to tumour cells. After RF hyperthermia, the tumour size decreased owing to apoptosis and necrosis of tumour cells.

A Novel Injection Technique to the Lateral Pterygoid Muscle for Temporomandibular Disorders: A Cadaveric Study.

BACKGROUND: Lateral pterygoid muscle activity is associated with the pathological mechanisms of some temporomandibular disorders. The authors aimed to define and demonstrate a novel, practical, and safe technique for botulinum toxin type A injection to the lateral pterygoid muscle based on their findings. Their secondary aims were to standardize the injection pattern according to the variations of the lateral pterygoid muscle and its surrounding anatomical structures, and to establish its advantages over intraoral injection. METHODS: Twenty cadaver heads were dissected. The lateral pterygoid muscle and its surrounding structures were investigated for anatomical variations. Based on these findings, a standardized extraoral injection protocol was defined and compared with the intraoral technique for accuracy and safety. RESULTS: The average depth of the lateral pterygoid plate from the skin surface was 49.9 ± 2.2 mm, and the mean width of the lateral pterygoid plate was 10.5 ± 3.9 mm. The extraoral injection approach based on the location of the maxillary tuberosity, tragus, and lateral pterygoid plate was consistent in all dissections for the accuracy of the intramuscular injection. In the intraoral approach, standardization of the entry point of the needle through the oral mucosa is difficult, which makes adjustment of the depth of the injection challenging while increasing the risk of neurovascular injury. CONCLUSIONS: The clinical significance of the lateral pterygoid muscle makes it worthwhile to implement minimally invasive treatments before considering more invasive options. The authors define a safe, accurate, and reliable approach with ease of administration in patients with temporomandibular disorders.

Treatment of En Coup de Sabre Deformity with Fat Grafting and Demineralized Bone Matrix: A Case Series.

En coup de sabre deformity (ECDS) is a form of localized scleroderma in the frontoparietal region caused by progressive subcutaneous tissue atrophy and bony defect. Although ECDS involves two layers, skin/subcutaneous tissue and bone, the existing literature mainly focuses only on treating the skin/subcutaneous tissue layer. In this case series, we aimed to propose a novel approach that includes the combined use of fat grafting and demineralized bone matrix (DBM). Four patients with ECDS deformity, operated between February 2016 and October 2018, were retrospectively evaluated. All the patients were treated with the novel approach. Patients were evaluated with localized scleroderma scale and computed tomography (CT) scan in the preoperative period and at the annual follow-up. We observed remarkable improvement in the localized scleroderma scale including appearance, palpation, and size scores in all patients at the annual follow-up. CT scans at the annual follow-up revealed new callus formation at the bony defect area in all patients. Reinforcing fat grafting with DBM could promote healing of the bony and skin/subcutaneous tissue defects associated with ECDS.

Airflow Considerations and the Effect of Webster's Triangle in Reduction Rhinoplasty.

BACKGROUND: Reduction rhinoplasties, regardless of the methods used (structural or preservation), can cause a reduction in the internal nasal volume, which may lead to breathing problems. In 1977, Webster proposed preserving a little triangle in the beginning of the lower lateral osteotomy line to prevent breathing problem. However, its importance is still controversial. OBJECTIVES: and methods: This prospective randomized controlled study (level of evidence 1) included 46 patients without nasal breathing problem. High-to-low (Webster's triangle preservation) osteotomy (control group, n = 23) and low-to-low osteotomy (study group, n = 23) were performed. All operations were performed according to the proposed volumetric rhinoplasty steps (examination/measurement, prevention and treatment). Nasal obstruction symptom evaluation (NOSE) test, visual analog scale, acoustic rhinometry, rhinomanometry, peak nasal inspiratory flow (PNIF), and three-dimensional measurements were performed in all patients. Breathing tests were repeated before and 6 months after surgery with and without xylometazoline administration. RESULTS: No statistically significant difference in NOSE and visual analog scale scores was found between the two groups. Acoustic rhinometry, PNIF, and rhinomanometry findings showed no statistically significant breathing difference between the two groups. CONCLUSIONS: In reduction rhinoplasties, a decrease in the internal volume may be expected as directly proportional with the reduction amount. The decrease in the internal volume may create nasal breathing problems. To prevent it, nasal airflow should be adjusted according to new anatomy. In this study, we discussed "volumetric rhinoplasty" steps to prevent breathing problems in reduction rhinoplasty. Following these steps, not preserving Webster's triangle (low-to-low osteotomy) has no effect on the nasal airway. LEVEL OF EVIDENCE II: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Defining a Preauricular Safe Zone: A Cadaveric Study of the Frontotemporal Branch of the Facial Nerve.

BACKGROUND: In the preauricular region, the frontotemporal branch of the facial nerve is vulnerable to injury, which can result in facial palsy and poor cosmesis after surgical interventions. OBJECTIVES: The purpose of this study was to describe variations in the branching patterns of the frontotemporal branch of the facial nerve and the relation between this branch and the surrounding anatomic landmarks. Based on our findings, we propose a Danger Zone and Safe Zones for preauricular interventions to avoid frontal branch injury. METHODS: Twenty cadaveric half-heads, 10 freshly frozen and 10 embalmed, were dissected. The anatomy of the auriculotemporal nerve, facial nerve, and variations of its branching pattern in the preauricular region were investigated. RESULTS: The mean [standard deviation] number of frontotemporal branches crossing the zygomatic arch was 2.05 [0.6]. Beginning from the X point at the apex of the intertragal notch, frontal branches ran over the zygomatic arch at a distance extending from 10 to 31 mm anterior to the tragus, which can be defined as the Danger Zone for frontal branches. Safe Zones A and B are triangular regions located behind and in front of the Danger Zone, respectively. CONCLUSIONS: Mapping of these Safety and Danger Zones is a reliable and simple approach in preauricular interventions to avoid frontal branch injury because the facial nerve typically has multiple frontal branches. This approach provides practical information for surgeons rather than estimating the trajectory of a single frontal branch from Pitanuy's line.