Reprogramming activated astrocytes into GABAergic neurons to treat trigeminal neuralgia.

Reconstruction of central facial regions, particularly the lower eyelid and lateral nasal areas, continues to pose significant challenges for plastic surgeons. These regions encompass multiple esthetic subunits, necessitating meticulous consideration of texture compatibility and tension-free closure within each unit. Although various perforator flaps-such as those based on the facial artery or supraorbital artery-have been employed for mid-cheek reconstruction, achieving optimal contour and esthetic integration of the periorbital and nasal subunits remains difficult. In this study, we investigate the application of an infraorbital artery (IOA) perforator flap for the reconstruction of the lower eyelid and lateral nasal region, aiming to improve postoperative esthetic outcomes. This study provides an anatomical description and its clinical applications. In a cadaveric study, eight hemifaces were used to illustrate the precise location of the IOA, and the flap and artery pedicle were dissected to confirm surgical feasibility. Between August 2022 and May 2024, four patients underwent surgery with IOA perforator flaps to repair their lower eyelid or nose. Anatomical Study: In anatomical dissections, the mean distance between the infraorbital artery (IOA) and the infraorbital rim was 10.12 ± 1.10mm, while the mean diameter of the IOA at its origin from the infraorbital foramen measured 1.50 ± 1.09mm. During the dissection of the IOAP and its accompanying nerves, the mean diameter of the perforating vessels was approximately 0.5mm. The length of the vascular pedicle that could be mobilized ranged from 2 to 4cm. In the clinical series, four patients underwent reconstruction with an IOA perforator flap. All flaps survived without signs of necrosis or vascular compromise, indicating excellent flap viability and reliable perfusion. According to the FACE-Q assessment scale, patients showed significant improvements in both esthetic appearance and functional outcomes. The infraorbital artery perforator flap represents a feasible and effective option for the reconstruction of defects involving the nose and lower eyelid, offering superior contour restoration of the periorbital and nasal regions compared to alternative techniques. 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 the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Transarterial chemoembolization (TACE) has recently emerged as a new alternative and palliative treatment option for head and neck cancers in human medicine, with a few case reports in veterinary medicine also showing good outcomes for canine oronasal tumors. Therefore, this study aimed to analyze the anatomical structures of canine head arteries using computed tomography angiography (CTA), focusing on the feeding arteries of oronasal tumors, as this information is essential for interventional procedures. This retrospective multicenter study used triple-phase CTA images of nasal tumors (n=30), oral tumors (n=31) (including one case of a caudal mandibular tumor with two tumors), and a control group (n=51). Among the 100 feeding arteries identified in the 61 oronasal tumors, the descending palatine artery (27/45; 60%) had the highest prevalence in nasal tumors. In rostral maxillary tumors, the infraorbital artery (10/24; 41.7%) was identified as the major feeding artery, whereas in mandibular tumors, the facial artery was the most prevalent feeder in both the rostral (4/4; 100%) and caudal (6/7; 85.7%) locations. Of the 222 head arteries observed on CTA, all lingual and facial arteries originated separately. The mean diameters of the major head arteries in different groups were significantly and positively correlated with body weight. However, when comparing the diameters of the head arteries normalized to body weight between the tumor feeder group and the control group, no significant difference was observed. This study provided comprehensive information on canine head arteries, including the feeding arteries of oronasal tumors, which is important for preprocedural planning.

Vascular complications after facial filling with hyaluronic acid/poly-l-lactic acid (HA/PLLA) composite fillers are rare. Herein, the authors report a case of vascular occlusion after nose and nasolabial fold augmentation with HA/PLLA that resulted in necrosis of the gingival papilla and unilateral hard palate mucosa and pulpitis. To explain the pathogenesis of necrosis of the gingival papilla and unilateral hard palate mucosa, the authors hypothesized that an embolus was accidentally injected into the infraorbital artery and nasal septum branch of the upper lip artery and subsequently flowed into the branches of the great palatine artery through the abundant vascular anastomoses. Regarding the pathophysiology of the pulpitis, the authors presumed that bacteria or an embolus was injected into the infraorbital artery and subsequently entered the superior and inferior alveolar arteries through the maxillary artery, resulting in pulpitis. After receiving hyaluronidase injections, the patient's prognosis was favorable. In addition to being aware of the risk of embolism of the occult lesion created by using an HA/PLLA composite, surgeons should be knowledgeable about the anatomy of the nose and nasolabial fold. In cases of vascular embolization, hyaluronidase should be promptly administered in appropriate amounts at the filling injection site. To prevent exacerbation of the mucosal ischemia, small-volume, high-concentration, multipoint injections into the hard palate mucosa are advised.

Background/Objectives: The infraorbital canal (IOC) is a critical anatomical structure that passes through the anterior surface of the maxilla and opens at the infraorbital foramen, containing the infraorbital nerve, artery, and vein. Accurate localization of this canal in maxillofacial, dental implant, and orbital surgeries is of great importance to preventing nerve damage, reducing complications, and enabling successful surgical planning. The aim of this study is to perform automatic segmentation of the infraorbital canal in cone-beam computed tomography (CBCT) images using an artificial intelligence (AI)-based model. Methods: A total of 220 CBCT images of the IOC from 110 patients were labeled using the 3D Slicer software (version 4.10.2; MIT, Cambridge, MA, USA). The dataset was split into training, validation, and test sets at a ratio of 8:1:1. The nnU-Net v2 architecture was applied to the training and test datasets to predict and generate appropriate algorithm weight factors. The confusion matrix was used to check the accuracy and performance of the model. As a result of the test, the Dice Coefficient (DC), Intersection over the Union (IoU), F1-score, and 95% Hausdorff distance (95% HD) metrics were calculated. Results: By testing the model, the DC, IoU, F1-score, and 95% HD metric values were found to be 0.7792, 0.6402, 0.787, and 0.7661, respectively. According to the data obtained, the receiver operating characteristic (ROC) curve was drawn, and the AUC value under the curve was determined to be 0.91. Conclusions: Accurate identification and preservation of the IOC during surgical procedures are of critical importance to maintaining a patient's functional and sensory integrity. The findings of this study demonstrated that the IOC can be detected with high precision and accuracy using an AI-based automatic segmentation method in CBCT images. This approach has significant potential to reduce surgical risks and to enhance the safety of critical anatomical structures.

The safety of tear trough injections requires examination of the arterial topography in this region. The aim of this study was to elucidate the distribution of blood vessels in the tear trough region at a specific three-dimensional (3D) location. Computed tomography scans of 158 adult cadaver hemifaces were obtained and reconstructed, focusing on the origin of angular artery (AA) and the positioning of detoured facial artery (DeFA). The AA in the tear trough region has three main sources: 57.6% directly from the ophthalmic artery (OA), 38% from branches of the facial artery (FA), and 4.4% from branches of the infraorbital artery (IOA). Within this region, the detoured AA originating from the OA is observed in 3.8% of cases, located at a mean distance of 3.4 ±2.0 mm from the inferior orbital margin near the inner canthus. The DeFA is present in 38.6% of cases, located at a mean distance of 7.3 ±2.8 mm from the inferior orbital margin near the inner canthus. Additionally, the main arterial supply to the infraorbital area is provided by branches of the IOA (53.8%). 3D technology enables offer high-resolution guidance for clinical practice in the tear trough area. 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 the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Peripheral nerve sheath tumours present a diagnostic challenge. Only one case where ante-mortem diagnosis was achieved following a wedge biopsy is described in the literature; this is the first case described of canine peripheral nerve sheath tumour diagnosed via tru-cut biopsy. This technique represents a less invasive approach to diagnose trigeminal peripheral nerve sheath tumours. A 7-year-old female Bull Terrier presented with an 8-week history of left temporalis muscle atrophy and facial irritation. A subcutaneous mass was detected on the left maxilla at the level of the infraorbital foramen. Exophthalmos, atrophy of the temporalis and masseter muscles, and reduced sensation of the nostril were detected on the left side. Magnetic resonance imaging revealed enlargement and hyperintense signal intensity compared to muscle signal intensity in T2-weighted magnetic resonance images of the left mandibular and maxillary branches of the trigeminal nerve, extending into the infraorbital branch of the maxillary nerve, and enlargement of the infraorbital foramen was noted. Affected nerves showed marked heterogeneous contrast enhancement. Six ultrasound-guided tru-cut biopsies of the trigeminal nerve were taken, and histopathology and immunohistochemistry confirmed the diagnosis of a peripheral nerve sheath tumour. Surgical excision and radiation therapy were discussed, but a palliative approach was elected, and gabapentin was prescribed. The facial irritation improved but did not resolve. The patient was lost to follow up after a few weeks.

The endoscopic endonasal approach offers a safe, reliable, and minimally invasive method to access the pterygopalatine fossa. In this study, we provide a detailed anatomical exploration of the pterygopalatine fossa, with a particular focus on the nerves and their spatial relationships to key endoscopic landmarks. A total of 12 pterygopalatine fossae from six formalin-fixed cadaveric heads (five female, one male) were dissected using both endoscopic approach and anatomical microscopic dissection to measure the lengths, diameters, and anatomical relationships of the nerves and arteries. The maxillary nerve measured 15.93 ± 6.19 mm in length and 3.96 ± 0.69 mm in diameter, while infraorbital nerve measured 24.4 ± 4.38 mm in length and 3.00 ± 0.71 mm in diameter. The greater palatine nerve measured 13.15 ± 4.25 mm in length and 2.70 ± 0.39 mm in diameter. The Vidian nerve measured 16.78 ± 1.18 mm in length and 2.15 ± 0.51 mm in diameter. The pterygopalatine ganglion had a width of 4.59 ± 1.16 mm and a height of 5.18 ± 1.63 mm. The infraorbital nerves were primarily located lateral to the infraorbital artery, while the greater palatine nerves were typically found medial to the descending palatine arteries. Our findings indicate that the maxillary, infraorbital, and greater palatine nerves, together with the pterygopalatine ganglion, are key landmarks for defining the surgical boundaries of the pterygopalatine fossa. These insights are expected to enhance the safety and precision of surgical interventions in this complex anatomical region, ultimately improving patient outcomes.

Background/objectivesTo characterise the infraorbital artery (IOA) and its orbital branch, which are key structures encountered during inferior orbital explorations, with potential for orbital haemorrhage and vision loss if inappropriately handled.MethodsThirteen embalmed heads (26 orbits) were dissected. The following parameters were measured: orientation of the IOA in relation to the infraorbital nerve (ION); presence or absence of the orbital branch of the IOA; and the distance between the orbital branch of the IOA to the inferior orbital rim.ResultsIn the pterygopalatine fossa, the orientation of the IOA relative to V2 was medial (n = 9, 34.6%), inferior (n = 4, 15.4%), lateral (n = 4, 15.4%), inferolateral (n = 3, 11.5%), superolateral (n = 3, 11.5%), inferomedial (n = 2, 7.7%) and superior (n = 1, 3.8%). In the infraorbital canal, the IOA in relation to the ION was as follows: superomedial (n = 12, 46.2%), medial (n = 9, 34.6%), superior (n = 2, 7.7%), inferomedial (n = 2, 7.7%) and superolateral (n = 1, 3.8%). An orbital branch of the IOA was identified in 21/26 orbits (80.8%). The mean distance of the orbital branch to the inferior orbital rim was 13.0 ± 4.8 mm (range 2.0-23.0 mm).ConclusionsThe IOA is an important vascular structure to recognise during inferior orbitotomies. The most common configuration is an IOA that runs medially to V2 in the pterygopalatine fossa, then superomedially to the ION within the infraorbital canal. The orbital branch of the IOA emerges 13 mm posterior to the inferior orbital rim. Recognition of these arterial branches and appropriate cauterization are paramount for avoiding significant operative complications.

Objective: The infraorbital foramen is the hole on the face where the infraorbital canal, which carries the infraorbital artery, vein and nerve, opens. In our study, we aimed to investigate the infraorbital foramen, which is important in surgical procedures to be performed in the midface region, anatomically and morphometrically. Materials and Methods: In our study, 111 dry skulls and 144 hemifaces were used. The incidence and type of infraorbital foramen were classified. The incidence of accessory infraorbital foramen was investigated. The shortest distance of the infraorbital foramen to the nasal notch, infraorbital margin, alveolar juga of the canines, and the lower end of the zygomaticomaxillary suture; additionally, face width and nasal height were measured with a digital caliper. Results: As a result of the study, 69.4% of the infraorbital foramen in 144 hemifaces were oval, 15.3% were semilunar, 9% were round, and 0.7% were triangular. We did not encounter infraorbital foramen in 5.6% of the hemifaces.We found the average distance of the infraorbital foramen to the nasal notch as 15±1.9 mm, the shortest distance to the lower end of the zygomaticomaxillary suture as 25.37±2.26 mm, the distance to the infraorbital margin as 8.41±1.53 mm, and the distance to the alveolar juga of the canines as 29.79±2.9 mm. We found the mean face width to be 112.76±6.19 mm and the mean nose height to be 51.61±6.19 mm. Conclusion: The infraorbital foramen is an anatomical reference point used in oral and maxillofacial surgeries, especially for local anesthesia applications. In order to prevent nerve damage and provide reliable regional anesthesia during surgical interventions, it is important to have detailed information about the anatomical features of the infraorbital foramen. We believe that our study will provide information about the variations of the infraorbital foramen to clinicians and surgeons.

Soft-tissue filler injections, particularly hyaluronic acid, are popular for temple volume restoration. Although uncommon, this area poses risk for vision loss from embolic occlusion. Guidelines recommend injecting into the supraperiosteal plane for safety; however, the deep temporal arteries (DTAs) in this plane pose a risk. This study investigates potential pathways from the DTA to the ophthalmic artery (OA) and mechanisms of filler travel. Retrospective analysis of carotid angiograms from patients with marked carotid artery stenosis or vascular malformations, given that collaterals are more visible in the presence of vascular blockages. Select cases were identified by the neurosurgery team. Four anastomotic pathways between the DTA and OA were identified, displaying a combination of anterograde and retrograde flow. Case 1 shows direct DTA-lacrimal artery anastomosis. In cases 2 to 4, the DTA is shown originating from the internal maxillary artery (IMAX) following its anatomical course. Retrograde flow from the DTA into the IMAX can then lead to anterograde flow into branches connecting to the IMAX including the superficial temporal artery, infraorbital artery, and middle meningeal artery. These arteries then form collaterals with the OA. This study is the first to elucidate 4 potential routes for filler-induced OA occlusion originating from DTAs in the supraperiosteal plane. These pathways involve retrograde flow, a mechanism previously suggested for filler-induced occlusion. Notably, the likelihood of these pathways being traversed may be low due to their length and amount of filler volume required; however, it is not impossible.

Severe dry eyes often require surgical intervention. Submandibular salivary and minor salivary gland transplantation are options for refractory dry eyes but have limitations. The authors innovatively designed an insular infraorbital neurovascular pedicle labial salivary gland transplantation (IINPLSGT) and validated its feasibility and safety through anatomical studies. An anatomical study was conducted on 13 red-colored latex arterial-perfused cadavers (24 sides). Two specimens (4 sides) simulated IINPLSGT. The authors recorded the branching patterns and courses of the infraorbital artery, infraorbital nerve, and angular artery, as well as the distribution of nerves, vessels, and salivary glands in the upper lip. Infraorbital artery and angular artery were anatomically classified. The feasibility of the IINPLSGT was validated. Otolaryngologists and ophthalmologists performed IINPLSGT, transferring the labial mucosal flap to the lower eyelid conjunctival fornix to treat severe dry eye in 1 patient. Infraorbital artery exhibited 5 potential branches, classified into 5 types based on developmental patterns. Angular artery was classified into 3 types based on the courses. Patient symptoms significantly improved postoperatively, with Schirmer I increasing from 0 mm to 6 mm, noninvasive breakup time from 0 seconds to 6 seconds, and SPEED (Standard Patient Evaluation of Eye Dryness questionnaire) score decreasing from 10.5 to 3 in the OD 1 year after surgery. No severe complications were observed. IINPLSGT is a safe and feasible method for treating severe dry eyes. The procedure is simple, with a high postoperative gland survival rate, stable secretion, and minimal complications.

The infraorbital canal (IOC) houses critical structures like the infraorbital artery, vein, and nerve, and its atypical location within the maxillary sinus could pose risks during surgical procedures, making it crucial to understand its prevalence and distribution. The study aims to investigate the localization and frequency of the IOC within the maxillary sinus. This retrospective study analyzed computed tomography (CT) images from 1000 randomly selected patients (500 males, 500 females) aged 18 to 65 years who underwent paranasal region imaging at Istanbul Medipol University Medipol Mega University Hospital between 2015 and 2020. Exclusion criteria included major pathologies, prior surgeries, and poor image quality. The study focused on evaluating the localization of the IOC and its presence within the maxillary sinus, using coronal CT sections. The IOC was found within the maxillary sinus in 8% of cases (44 males, 36 females). This variation was bilateral in 34 cases and unilateral in 46 cases, with no statistically significant relationship between sex and the occurrence or type of variation. The study's findings align with previous research, which reported similar prevalence rates for this anatomical variation. The study confirms that the IOC is located within the maxillary sinus in a significant percentage of cases, emphasizing the importance of preoperative CT evaluation to prevent potential complications during maxillary sinus surgeries. These findings highlight the clinical relevance of considering individual anatomical differences in the localization of the IOC.

To provide a detailed examination of the arterial blood supply to the middle third of the nasal skin through cadaveric dissections, identifying the primary arterial sources and their precise locations. Cadaveric dissections were performed on 14 hemifaces from fresh specimens. The main feeding arteries and their branches were carefully dissected under magnification. Morphometric characteristics of the specimens, along with the caliber of the arteries and their branches vascularizing the mid-third nasal skin were recorded, and statistically analyzed. Four main arteries were identified as responsible for the blood supply to the mid-third of the nasal skin: the facial artery, the nasal branch of the infra-orbital artery (nbIOA), the dorsal nasal artery, and the upper branches of the columellar plexus. The lateral nasal artery (LNA) and the nbIOA were the main contributors, each providing significantly larger arterial branches than the other sources (1.8 ± 0.8 branches of 0.67 ± 0.2mm for the LNA, p-value < 0.001-1 ± 0 branches of 0.55 ± 0.17mm for the nbIOA, p-value < 0.01). The largest arterial branch consistently penetrated the lateral and inferior angle of the mid-third nasal skin, originated either from the LNA or nbIOA. The LNA and nbIOA endorse crucial roles in the arterial blood supply to the mid-third nasal skin. Despite the variability in vascular anatomy, a consistent pattern of arterial supply with convergence in the depth of the alarfacial groove was observed. Understanding these patterns is vital for improving surgical precision and reducing the risk of complications in both aesthetic and reconstructive surgeries.

Abstract Aim: The aim of this study is to evaluate the prevalence, localization and diameters of Posterior superior alveolar artery (PSAA), one of the branches of maxillary artery, and Infraorbital foramen (IOF) through which the Infraorbital artery (IOA) passes, by using conic beam computed tomography (CBCT) in dentate patients. The study also aims to research whether there is any relationship between PSAA, which has a small diameter and which sometimes cannot be seen on CBCT, and IOF, which has relatively larger diameter, in terms of size, shape and localization and to predict their location relative to each other in surgical procedures involving the maxillary sinus in edentulous patients. Material and Method: Bilateral maxillary sinuses were analysed retrospectively in CBCT images taken for various reasons from 170 patients with no missing teeth in the maxillary posterior region. Demographic characteristics of patients such as age and gender and their radiological findings were recorded. The largest locations of PSAA and IOF in the maxillary sinus were determined and their size, shape, localization in relation to the teeth and their distances from anatomical points such as the midline, medial wall and base of the maxillary sinus and crest were evaluated. Results: While 49.42% of the participants were male, 50.58% were female and mean age was 28.88 ± 9.95. The incidence rate of PSAA on CBCT was found as 56.2%. While the rate of those with a vertical diameter of ≥1 mm was 92.1%, the rate of those with a horizontal diameter of ≥1 mm was 65.4%. When the relationship of PSAA with the maxillary sinus was examined, the most common location was intraosseous with 60.2%. In terms of localization, the highest rate was found in the distal of the second molar with 34.6%. IOF was observed in all CBCT images (100%). Mean horizontal diameter of IOF was found as 3.47 mm, while its mean vertical diameter was found as 3.68 mm. In terms of shape, the most common shape was semi-circular (49.4%). In terms of localization, the most common location was at the second premolar tooth level with a rate of 39.7%. While IOF was mostly seen at the first premolar tooth level in young participants, it was mostly seen at the distal of second premolar tooth in old age. No statistical correlation was found between the diameters, localizations and shapes of PSAA and IOF (p&gt;0.05). However, the median values of horizontal diameter, vertical diameter, distance to the midline, distance to the medial wall and base of the maxillary sinus and distance to the crest were found to be higher in men when compared to women in both anatomical structures. Conclusion: According to the results of this study, in order to prevent a possible bleeding that can occur since PSAA and IOF diameters are higher in men than women and since the vertical and horizontal diameters of PSAA are higher than 1 mm in a great majority of the patients, clinicians are recommended to evaluate the size and localization of these anatomical structures with CBCT before surgical procedures, especially in male patients and older patients. In the present study, no statistical correlation was found between PSAA, one of the branches of maxillary artery, and IOF, through which IOA passes, in terms of characteristics such as localization, distance to anatomical points and shape and our hypothesis of predicting their position relative to each other in surgical procedures of the maxillary sinus in edentulous patients was not confirmed. It may be useful to conduct more detailed studies with higher resolution CBCT devices in which more patients are included.

Although the canal protects the infraorbital nerve and artery, they can be easily injured during manipulation in this area. This study aimed to examine the structure and position of the infraorbital canal (IOC) and nearby features using cone beam computed tomography (CBCT) images. This study was conducted on 94 CBCT images (47 men and 47 women of 20-55years). The infraorbital groove (IOG), infraorbital foramen (IOF) and infraorbital canal (IOC) points, and other related parameters are investigated bilaterally using OnDemand3D software. Data were studied by paired t, independent t, and Kruskal-Wallis statistical tests (α = 0.05). The average angle between IOC, sagittal, axial planes, and IOG 29.08° (SD = 7.33), 56.01° (SD = 10.39), and 121.44° (SD = 43.44). The average IOC and IOG lengths were 10.83 (SD = 3.87) and 19.01 (SD = 5.81) mm. The average IOF vertical diameter was 5.5 (SD = 1.80) mm. The mean skin thickness over IOF was 10.38 (SD = 2.42) mm. The average length between the IOF and the infraorbital rim, the lateral nasal wall, the midsagittal plane, the line perpendicular to the axis of the canine apex, the occlusal plane of the premolar, the vertical axis of the lateral rim of the frontozygomatic suture 9.7 (SD = 2.52), 11.76 (SD = 2.92), 16.4 (SD = 6.42), and 91.11 (SD = 4.15), 42 (SD = 7.61) and 22.55 (SD = 3.25) mm. Images showed the presence of accessory IOF in 13.45% of cases, and the presence of Haller cells in 17.75% of cases, and sex did not affect the studied variables. CBCT is an accurate 3-dimensional imaging modality for assessment of the anatomy of the IOC, IOG, and IOF. Knowledge of the IOC/G anatomy for preoperative treatment planning utilizing CBCT can assist surgeons in avoiding potential surgical complications and improving treatment efficacy.

Congenital cleft of the secondary palate occurs when there is failure of one or both maxillary processes to fuse with the nasal septum during embryonic development. Palatal cleft severity can range from a simple focal fissure of the caudal soft palate to full-thickness defects of varied widths involving the entire soft and hard palate. A novel staged medially positioned single mucoperiosteal flap technique in 4 canine patients is reported. This flap technique is based on the major palatine and infraorbital arteries with strategic extractions of maxillary teeth and placement of allograft membrane in 3 of 4 cases for treatment of clefts wider than may be repaired effectively by traditional methods.

Anatomical variations are a common feature of the human anatomy. Variation can explain some pathological conditions and is important to keep them in mind during surgical procedures. The relations between nerves and their adjacent arteries have been proposed to play a role in the generation of peripheral trigger migraines. Close opposition between nerves and arteries can lead to vascular compression of the nerve that triggers episodes of pain. We did a routine dissection of the infratemporal fossa and orbital floor by opening the maxillary sinus. Here we report a case where the infraorbital nerves form a nervous loop entrapping the infraorbital artery in the infraorbital channel. Similar cases of close nervous and arterial apposition are described for the auriculotemporal and occipital nerves. We think that accumulating knowledge of these rare variations could expand our understanding of rare conditions such as primary infraorbital neuralgia.

Infraorbital filler injection is a commonly used minimally invasive cosmetic procedure on the face, which can cause vascular complications. In this study, we aimed to explore the anatomical structure of the infraorbital vasculature and to establish an accurate protocol for infraorbital filler injection. The vascular structure of the infraorbital region was evaluated in 84 hemifacial specimens using computed tomography. Four segments (P1-P4) and five sections (C1-C5) were considered. We recorded the number of identified arteries in each slice and at each location and the number of deep arteries. Furthermore, we also measured the infraorbital artery (IOA) distribution. At P1-P4, the lowest number of arteries was detected in segment P4, with a 317/1727 (18.4%) and 65/338 (2.3%) probability of total and deep arterial identification, respectively. The probabilities of encountering an identified artery at the five designated locations (C1-C5) were 277/1727 (16%), 318/1727 (18.4%), 410/1727 (23.7%), 397/1727 (23%), and 325/1727 (18.8%), respectively. The probability of an IOA being identified at C2 was 68/84 (81%). We described an effective filler injection technique in the infraorbital region to minimize the associated risks. 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 the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

The aim of this study is to investigate the origin and course of the orbital fat arterial supply in the lower eyelid using traditional anatomy and three-dimensional computed tomography (CT). Twenty-seven cadaver heads were infused with mercury sulfide contrast media through the ophthalmic artery, maxillary artery, transverse facial artery, and facial artery. CT images were obtained after contrast agent injection, three-dimensional CT scans were reconstructed, and the cadaver heads were dissected. Forty-five qualified hemifaces showed that the orbital fat arterial supply in the lower eyelid originates primarily from the inferomedial muscular trunk (IMT) of the ophthalmic artery and the orbital branch of the infraorbital artery. The medial branch of the IMT terminated at the medial fat pad (35.6%) or the orbital floor (64.4%). The lateral branch terminated at the inferior oblique (IO) muscle (28.9%) or the central and lateral fat pads (17.8%). In 53.3%, the lateral branch extended to the anterior part of the lateral fat pad and terminated in the orbital wall or the zygomaticoorbital foramina. The orbital branch of the infraorbital artery coursed between the orbital floor and the orbital fat, providing supply to the IO muscle, inferior rectus (IR) muscle, nasolacrimal duct, and orbital fat. This study elucidated the origin and course of the orbital fat arterial supply in the lower eyelid, which may help to avoid reducing the blood supply of the orbital fat pedicles during surgery. 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 the Table of Contents or the online Instructions to Authors www.springer.com/00266 .