Orbicularis Oris Research Articles

Transconjunctival correction of involutional entropion: A video demonstration.

Involution or aging is the most common cause of lower eyelid entropion (in-turning of eyelid margin) in the elderly population. Various pathomechanisms have been postulated for its occurrence. Aging leads to laxity of tissues and loss of muscle tone. Disinsertion/dehiscence of inferior retractors is considered as the major reason along with the loss of orbicularis muscle tone with or without over-riding of pre-septal fibers onto pretarsal fibers, and laxity of overall eyelid and/canthal tendons. The examination should focus on testing the above-mentioned predisposing factors. The clinical tests are as below. 1. Distraction/pinch test-This test is conducted to assess the overall eyelid laxity. The patient is asked to look in the primary gaze and the lower eyelid is pulled away from the globe. The distance between the pulled eyelid and the globe is measured in millimeters. The laxity is considered significant if the value is more than 6 to 8 mm, which varies according to the age of the patient. 2. Snapback test-This test is conducted to assess the tone of the orbicularis muscle. After doing the distraction test, leave the eyelid and check for its position in relation to the globe. If it snaps back immediately or follows a blink, then it is normal for an old patient. If on leaving the eyelid, it does not come in contact with the globe after blinking repeatedly, then the loss of tone is significant. 3. Medial canthal laxity-Pull the eyelid laterally and observe the shift of the puncta. Laxity is significant if the shift of puncta is 4 mm. 4. Lateral canthal laxity-Pull the eyelid medially and observe the shift of the lateral canthus. Laxity is significant if the shift of the lateral canthus is 4 mm. 5. Eyelid sagging/sclera show-The presence of the sclera due to eyelid sagging is suggestive of significant horizontal lid laxity. 6. Inferior retractor weakness-Inferior retractor weakness occurs because of its dehiscence or disinsertion. The presence of the following signs is suggestive of weakness, that is, higher eyelid resting in primary gaze, eyelid fails to retract on down gaze (normal excursion of the lower eyelid is 3-4 mm), increase in the depth of inferior fornix, and presence of white infratarsal band of retractors separated from the lower tarsal border by a pinkish orbicularis band. Surgical management of involutional entropion includes tackling the vertical component (inferior retractors reinsertion/plication or eyelid margin rotation surgery) with or without the horizontal component. Horizontal tightening (lateral tarsal strip procedure or full-thickness pentagon excision) is indicated in the presence of significant laxity of the overall eyelid and/or canthal laxity. Tackling both vertical and horizontal components gives the best long-term outcome. To highlight important surgical steps of transconjunctival correction of left eye involutional entropion in a 70-year-old patient. The video 1 shows the correction of involution entropion by horizontal tightening (lateral tarsal strip procedure) and vertical tightening (advancement and reattachment of inferior retractors on the anterior surface of the tarsus) by conjunctival approach. The limitations of the procedure are mainly that it needs surgical expertise and excessive skin excision if needed cannot be conducted. In our experience, skin excision is not needed in unilateral cases to avoid asymmetry. The suture removal especially at the eyelid margin should be removed at 2-3 weeks to provide a strong attachment of inferior retractors with the tarsal surface. Steps of transconjunctival correction of involutional entropion.Video Link:https://youtu.be/JVLi0PngKm4.

The efficacy of non-depolarizing muscle relaxant as adjuvants to local anesthesia in peribulbar block during cataract surgery

Peribulbar anesthesia is mainly used for cataract surgery. Many studies had used atracurium and rocuronium as an additive to the local anesthetic (LA) drugs in eye surgery. The aim of this study is to evaluate the efficacy of adding atracurium versus rocuronium to a local anesthetic mixture, in providing an early onset of orbital akinesia and corneal anesthesia during cataract surgery. Ninety-three patients met the inclusion criteria and gave a written informed consent to participate. Patients were randomly allocated in three study groups (31 patients in each group). Group I received either 3 mL of a lidocaine2%(mixed by hyaluronidase 50 IU/ml) and 3 ml bupivacaine mixture, plus 0.5 mL rocuronium (5 mg) total volume 6.5 ml. Group II 3 mL of a lidocaine2%(mixed by hyaluronidase 50 IU/ml) and 3 ml bupivacaine mixture plus 0.5 mL (5 mg) atracurium total volume 6.5 ml. Group III or3 mL of a lidocaine2%(mixed by hyaluronidase 50 IU/ml) and − 3 ml bupivacaine mixture, plus 0.5 mL saline total volume 6.5 ml. The onset time of orbital akinesia was significantly lower in the rocuronium group and the atracurium group compared to the control group. Akinesia score was (0.90 ± 0.30) and (0.19 ± 0.40) in rocuronium group at 4 min and 6 min respectively which result in highly significant difference than atracurium and control groups. The use of rocuronium and atracurium will result in rapid orbital akinesia and rapid orbicularis muscle akinesia.

Three-Dimensional Efficacy Evaluation of Nasal Symmetry in Unilateral Cleft Lip Primary Repair: A Modified Rotation Advancement Technique

Objective: Objective assessment of the long-term postoperative outcomes of a modified rotation advancement combined with force balance orbicularis oris muscle reconstruction in patients with unilateral complete cleft lip and palate. Methods: Consecutive patients undergoing cleft lip primary repair were included (n=90). Three-dimensional images preoperatively (n=90), postoperatively (n=90), and at 5 years follow-up (n=57) were assessed and compared to age-matched controls. Results: In preoperative measurement, the subnasale and pronasale both exhibited a significant deviation. The cleft subalare was displaced both medially and posteriorly in comparison to the controls. Conversely, the noncleft subalare demonstrated a lateral drift. These observations collectively indicated an overall lateral drift of the nasal base towards the noncleft side. Surgical intervention successfully resulted in landmark positions that closely mirrored those of the controls. The symmetry of the nasal base was maintained at late follow-up within the cleft lip group. However, there was a significant downward and retrusive displacement of the cleft alar base, along with a notable lateral displacement of the subnasale and the noncleft alar base in both the cleft lip and alveolus/palate groups. Conclusion: The modified rotation advancement technique combined with force balance reconstruction of orbicularis oris results in promising symmetry of nasal base in patients with unilateral complete cleft lip. The alar base retrusion in patients with cleft lip and alveolus/palate is probably due to bony defect, which might be addressed by secondary alveolar bone grafting.

Histological and Molecular Manifestations of Cleft Myopathy.

Apart from rupture and displacement of muscle fibers, structural defects exist in cleft muscles but have not been adequately investigated. This study aimed to examine the histological and molecular features of the cleft muscles. Orbicularis oris (OO) and tensor fasciae latae (TFL) muscle samples were obtained from patients with cleft lip and alveolar. The non-cleft OO muscles were obtained from patients with facial trauma. Myofiber histology, stem cell composition, and molecular signatures were compared among the cleft OO muscle, non-cleft OO muscle, and TFL muscle. Histological analysis of the fibrotic area, myofiber size, fiber type composition, and dystrophin expression pattern was performed to characterize the pathological manifestations in cleft muscles. Immunofluorescent staining of Pax7+ muscle satellite cells (MuSCs) and PDGFRα+ fibro-adipogenic progenitors (FAPs) and transcriptional profiling of MuSCs were carried out to explore the stem cell number and behavior in the cleft muscle. Cleft muscles had an increased fibrotic area, variation in fiber size, and proportion of human fast myofiber. The defect in dystrophin expression was considerable in the non-cleft OO muscle and was even higher in the cleft OO muscle. MuSCs from cleft muscles showed a trend of increased Dux4 signature gene expression and repressed Pax7 target gene expression. Cleft myopathy resembles facial muscle-specific muscular dystrophy. The characterization of structural deformity inherited in cleft muscles could pave the way for a deeper understanding of orofacial cleft pathology.

Intraoperative stimulation mapping of sensory branches of the trigeminal nerve using unconditioned reflexes

Introduction: Intraoperative stimulation mapping enables to determine the location of nerves in the surgical field when visualization is difficult, as well as to identify visualized nerves, thereby reducing the risk of postoperative iatrogenic complications. Motor nerve mapping is widely used in neurosurgical procedures but only a few attempts at intraoperative sensory nerve mapping have been reported to date. The introduction of an effective method for mapping the sensory branches/portions of the trigeminal nerve can reduce the risk of complications such as facial hypo- and hyperesthesia after operations in the posterior cranial fossa. Objective: To demonstrate the possibility of using unconditioned reflex motor reactions for stimulation mapping of the sensory branches/portions of the trigeminal nerve.Methods: Intraoperative neuromonitoring records were analyzed in three patients with trigeminal neuralgia who underwent nerve stimulation mapping during microvascular decompression. The using of an extended to 40 ms time window for recording myographic responses enabled to record both short-latency direct motor responses to stimulation of motor nerves and long-latency reflex motor responses to stimulation of the sensory branches of the trigeminal nerve. Results: It was shown that unconditioned reflex reactions of the orbicularis oculi muscle (stimulation of the V1 portion of the trigeminal nerve, blink reflex) and tongue muscles (stimulation of V3, trigemino hypoglossal reflex) were successfully induced in patients under total intravenous anesthesia with both monopolar and bipolar stimulation. One patient also showed a reaction of the orbicularis oris muscle (stimulation of V2, snout reflex). The technique used enabled to differentiate not only the motor and sensory roots of the trigeminal nerve, but also its different sensory portions separately.Conclusion: The intraoperative stimulation mapping of sensory branches/portions of the trigeminal nerve via unconditioned reflex motor responses can be performed using the equipment and anesthesia regimen typical for motor nerve mapping. Received 10 October 2024. Revised 1 November 2024. Accepted 12 November 2024. Informed consentThe patients’ informed consent to use the records for medical purposes is obtained. FundingThe study was supported by the grant of Russian Science Foundation No. 23-25-00322. Conflict of interestThe authors declare no conflict of interest. Contribution of the authorsThe authors contributed equally to this article.

Effectiveness of comprehensive approach in rejuvenating the aging lower periorbita.

To investigate the efficacy of a comprehensive surgical approach for rejuvenation of the aging lower periorbita. Between February 2018 and January 2023, 80 eyes of 40 patients with lower lid dermatochalasis (LLD), lower lid laxity (LLL) or orbicularis laxity of the lower lid (OL) admitted to the oculoplastic surgery department of our clinic were included in the study. 18 eyes had LLD, 14 eyes had LLL, 18 eyes had LLD and LLL, and 30 eyes had LLD, LLL and OL. Patients were re-evaluated preoperatively, postoperatively at 1st week, 1st month and 6th month. In the LLD scoring, skin laxity was evaluated as 1 point for skin laxity, 2 points for fat prolapse, 3 points for tear trough deformity, 1 point for LLL and 1 point for OL. Patients with a total score below 3 points were defined as mild, and patients with a score of 3 and above were defined as advanced. Of the 40 patients, 30 were female (75%), 10 were male (25%) and the mean age was 56.7years (45.67years). Eighteen (22.5%) eyes underwent lower lid blepharoplasty (LLB) only, 14 (17.5%) eyes underwent lateral retinacular suspension (LRS) only, 18 (22.5%) eyes underwent LLB and LRS, 30 (37.5%) eyes underwent LLB, LRS and orbicularis muscle suspension (OMS).78 (97. 5 eyes with upper lid dermatochalasis underwent concomitant upper lid blepharoplasty (ULB) and 42 eyes (52.5%) with brow ptosis underwent additional browpexy. As a result of scoring, 34 eyes (42.5%) had mild and 46 eyes (57.5%) had severe lower periorbital aging. As a result of combined surgical treatments for each sign of aging of the lower periorbita in all patients, complications such as lid malpositioning, corneal exposure, orbital hemorrhage were not seen in any eye and surgical and cosmetic success was achieved. In patients with varying degrees of lower periorbital aging, a comprehensive surgical treatment can provide effective and safe results in rejuvenating the lower periorbital area. Additional treatments such as LRS and OMS have the advantage of providing a comprehensive approach to skin and muscle tightening while maintaining support to the lateral canthus and improving the lid-cheek junction.

How I Do It : Bilateral Cleft Lip Repair

Several techniques have evolved to achieve better outcomes in bilateral cleft lip repair. The techniques performed should overcome the challenge presented in bilateral cleft lip, such as protrusion of premaxilla, the short columella, the wide gap, minimal dry mucosa in prolabium also the low socioeconomic level that typically presented in cleft patient. Considering the challenges mentioned above, a proper design and precise technique should be defined. We proposed a design and technique with promising results, which involves: 1) The precision of the design, the adjustable point of the design to modify lateral flap will provide adequate thickness of vermillion to create tubercle as well as to provide adequate tissue for nasal floor. 2) The possibility to approximate the orbicularis oris muscle although the premaxilla is protruded. It is beneficial and cost-effective for the patients who cannot afford preoperative orthodontic treatment. 3) The suggestion to not worry about the immediate postoperative result as it will evolve to a satisfactory result. 4) The use of non-absorbable nylon 5.0 and 6.0 for the whole layers will overcome tension and reduce cost.

Botulinum Toxin: A Non-surgical Approach for Non-myasthenic Mild-to-Moderate Blepharoptosis Treatment.

Mild-to-moderate blepharoptosis can be aesthetically displeasing for patients, particularly in cases involving a single eyelid. However, certain patients are reluctant to undergo surgical intervention. Botulinum neurotoxin A (BoNT-A) injection offers a potential solution in such cases. Patients meeting the following inclusion criteria were included in the study: mild-to-moderate eyelid ptosis of different etiologies (excluding myasthenic disorders), robust activity of the orbicularis oculi muscle, proficiency in Italian language, standardized pre- and postoperative photo-documentation, and signed consent for study participation. A 32-33 Gauge 4-mm needle was employed to inject the BoNT-A in the pretarsal orbicularis muscle. Standardized videos and photos were obtained before the treatment, 2 weeks, 4 weeks, and 24 weeks post-treatment. Outcomes were evaluated by measuring changes in the margin reflex distance-1 (MRD-1) and assessing patient point of view through two subjective questionnaires. Forty-nine patients were enrolled, 39 females and 10 males, aged between 30 and 88 years old. We observed a significant increase in the MRD-1 after 2 weeks and after 4 weeks compared to the baseline (p < 0.0001), with a mean elevation of the eyelid of 0.71 mm and 0.67 mm respectively. Patients ceased to require furrowing of the frontalis muscle to compensate for the eyelid elevation dysfunction. After 24 weeks, the BoNT-A effect diminished, and the treated eyelid returned to its baseline position. 67.4% of patients reported an improvement with only mild inconvenience in their blepharoptosis, and 16.3% of patients reported a complete improvement. 85.7% of patients expressed the desire to undergo the treatment again. BoNT-A has demonstrated effectiveness in temporarily managing mild-to-moderate blepharoptosis and may represent a viable option for addressing minor eyelids asymmetries. 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 .

Combining local flap with depressor anguli oris transfer for lower lip reconstruction and orbicularis oris sphincter function restoration.

Despite the versatility of flap designs for lower lip reconstruction, the notion of orbicularis oris (OO) ring integrity was barely stressed. Traditional flap transfer leads to fibrous orientation inconsistency with the remaining OO. Therefore, the aim of this study is to share the experience of combining local flaps with depressor anguli oris (DAO) transfer for lower lip reconstruction and OO sphincter function restoration. 48 patients were included in this study. Four types of local flaps were transferred for lower lip reconstruction. Each technique was modified by adding an additional DAO transfer for OO reconstruction. Functional outcomes were evaluated by grading scales based on clinical examination and observation. Aesthetic outcomes were evaluated by Patient and Observer Scar Assessment Scale. The surgical outcomes were favorable in both functional and aesthetic aspects. No statistically significant differences were observed among different types of flaps. Patients at T1 stage showed statistically significant mouth opening compared with patients at T2 stage (P = 0.004). Patients whose commissure was preserved showed statistically significantly better competence compared with patients whose commissure was sacrificed (P = 0.006). Combining local flap with DAO transfer is a reliable and effective approach for lower lip reconstruction and OO sphincter function restoration. Moreover, the modiolus seems to play a vital role in enhancing competence. Thus, it should be preserved during oncologic ablation if possible. It is vital to match the orientation of the transferred muscle fiber with the orientation of the remaining OO. Therefore, DAO becomes an excellent candidate.

Restoration of Oral Competence With Local Advancement Flap After Free-Flap Reconstruction.

Surgical management of head and neck cancer (HNC) can result in significant functional deficits. Large tumors of the oral cavity may require extensive resection and the need for microvascular free-flap reconstruction involving the use of adynamic tissue. This may result in oral incompetence, drooling, and unsatisfactory esthetic outcomes. Maintenance of the orbicularis oris and function of the oral sphincter are important objectives in the reconstruction of large defects. When this cannot be accomplished, secondary local flaps can be employed to restore the orbicularis oris. We present 2 cases of oral incompetence following microvascular free- flap reconstruction for large resections of HNC. All cases were managed with debulking of flap, modified Karapandzic flaps, and advancement of composite skin, muscle, and buccal mucosa to restore the function of the oral sphincter and improve oral competence. The surgical techniques demonstrated in our cases resulted in improvement in both functional and esthetic outcomes. Restoring continuity of the orbicularis oris muscle is a critical functional and esthetic consideration in microvascular free flap reconstruction where the lip is involved or disrupted. However, when this cannot be achieved, restoration of the oral sphincter and oral commissure can be achieved with a secondary reconstructive procedure.

Functional and Aesthetic Lower Lip Reconstruction With Depressor Anguli Oris Muscle Flap and Reverse Superior Labial Artery Flap.

The lower lip is an important anatomical structure involved in daily activities such as eating, drinking, and speaking, as well as in facial expressions. Lower lip defects should be repaired to preserve lip function without disrupting the aesthetic harmony of the lips within the face. This goal is difficult for plastic surgeons because, for functional and aesthetic repair, it is necessary to replace the mucosa, muscle (especially contractile), and skin tissues present in the lip. Subtotal lower lip repair was performed using an innervated depressor anguli oris muscle flap and a desepithelialized reverse superior labial artery flap in seven male patients with a mean age of 63 years. A depressor anguli oris muscle flap was used to repair the orbicularis oris muscle defect. The desepithelialized part of the reverse superior labial artery flap was used for mucosal defect repair, whereas the remaining part was used for skin defect repair. Patients were followed up for an average of 15 months. Patient lips, epithelialization, sensation, and sphincter function were clinically evaluated. Electromyography (EMG) was performed at 6 and 12 months to evaluate the function of the depressor anguli oris muscle flap. All the reverse superior labial artery flaps survived without any loss. Trapdoor deformity developed in the flaps of two patients. The desepithelialized parts of the flaps were completely epithelialized (covered with mucosa) by approximately 6th week. In the EMG controls of the patients at 6 months, the depressor anguli oris muscle was contractible. Sensation regained in the operated lip during the follow-up period. The combination of an innervated depressor anguli oris muscle flap and a desepithelialized reverse superior labial artery flap is an important surgical option for the functional and aesthetic repair of subtotal lower lip defects.

Selective midfacial neurectomy for postparalytic facial nerve syndrome.

Chemodenervation with botulinum A toxin and neuromuscular retraining therapy are commonly performed as first-line treatments for postparalytic facial nerve syndrome (PFS). However, their effects are temporary, and side effects typically develop. Currently available selective neurectomy approaches are limited by variations in the anatomy of the peripheral branches of the facial nerve and the ability to reduce perioral synkinesis, but not periocular synkinesis. We devised a novel selective midfacial neurectomy for PFS that considers anatomical characteristics and is effective for both periocular and perioral synkinesis. In our approach, the facial flap was elevated subcutaneously, and facial nerve branches were identified at the anterior margin of the parotid gland. Using intraoperative nerve stimulation, the thin cranial zygomatic branches that innervate the lateral portion of the orbicularis oculi muscle and the buccal branches that innervate the orbicularis oris muscle independently were preserved. The thick caudal zygomatic branch and its communicating branch with the cranial buccal branches, which simultaneously and strongly contract both the periocular and perioral mimetic muscles, especially around the medial upper and lower eyelids, were selectively excised. From March 2021 to September 2022, selective midfacial neurectomy was performed in five patients with House-Brackman (HB) grade III-IV unilateral facial paralysis. With respect to the synkinesis score and palpebral fissure width ratio, statistically significant improvements were observed between the preoperative and 18-month postoperative values. Selective midfacial neurectomy is effective in treating patients with postparalytic facial nerve syndrome.

Physiological and Functional Restoration of the Modiolus Using a Double Tendon Sling in Patients With Full-Thickness Oral Defects.

Reconstruction of the oral modiolus should be considered for facial defects involving the lip and cheek. We have performed free flap reconstruction using a novel technique that includes a vertical and a horizontal sling for full-thickness defects involving the oral commissure. We used a free radial forearm flap and the palmaris longus tendon to correct lip and cheek defects in 6 patients (3 men, 3 women; age, 55-84 years). The tendon was divided into 2 portions for use as the double sling. One sling was used to connect the upper and lower stumps of the orbicularis oris in the vertical direction and the other to connect the vertical sling and masseter muscle. The outcomes assessed were esthetic appearance and functional results. The facial defects ranged in size from 3.0 cm × 4.0 cm to 7.0 cm × 6.0 cm and the mucosal defects from 1.5 cm × 4.0 cm to 6.5 cm × 5.0 cm. The length of the harvested tendon ranged from 11.5 to 13.5 cm. All flaps survived without complications. Good esthetic outcomes were achieved (excellent facial appearance, n = 1; no lip deviation or drooping, n = 5). Functionally, all patients had acceptable mouth opening and were able to eat a regular diet. Good physiological and functional results can be achieved using a double tendon sling for reconstruction of the modiolus in patients with full-thickness defects involving the oral commissure.

Surgical Correction of Secondary Bilateral Cleft lip and Nasal Deformities Using the Delaire-Precious Technique.

This study aimed to determine the efficacy of the surgical correction of secondary bilateral cleft lip and nasal deformities using the Delaire-Precious technique for Asian patients with bilateral cleft lip +/- palate (BCL+/-P). Retrospective cohort study. Thirty-six patients with BCL+/-P in Japan, the Philippines, and Vietnam underwent secondary lip correction using the Delaire-Precious technique by a single surgeon. The critical concepts of this surgical technique are discussed and clarified. A patient/parent satisfaction survey was carried out to evaluate the usefulness of this technique. The Delaire-Precious technique improves Cupid's bow's symmetry and the central tubercule's volume. The scar tissue between lateral and medial philtrum incisions is excised. The orbicularis oris muscle is then reconstructed with a midline suture placed above the periosteum of the premaxilla. Most patients (90.9%) and all parents were at satisfied with the surgical result. The technique was highly satisfactory to patients and parents except at the level of scar correction. The secondary bilateral cleft lip and nasal repair using the Delaire-Precious technique is an adaptable technique that can be applied to various ethnic groups. It was found to be a satisfactory technique for Asian patients with BCL+/-P.

Describing the musculature of mystacial pads in harbour seals (Phoca vitulina) using diceCT.

Pinnipeds have long, sensitive, moveable mystacial vibrissae. In other mammals, intrinsic muscles contribute to protracting the vibrissae. However, the mystacial muscles of pinnipeds have not yet been systematically described. Using traditional histological methods provides us with two-dimensional muscle images, but having the ability to visualise these structures in three dimensions would allow for a more comprehensive understanding of pinniped vibrissal anatomy, especially given the challenges posed by their large and extremely curved mystacial pad. We predicted that harbour seals would have large, regular intrinsic muscles due to their well-organised, moveable vibrissae. We adopted diffusible iodine contrast-enhanced computer tomography (diceCT) to describe, for the first time, the three-dimensional architecture of the mystacial vibrissal muscles found in harbour seals. Our observations show that their vibrissae are organised into grids within the mystacial pad. We identified both sling-shaped and oblique intrinsic muscles that connect one vibrissae to the next in the same row. We also identified extrinsic muscles, including the m. nasolabialis, m. maxillolabialis, m. levator nasolabialis and m. orbicularis oris. Contrary to our prediction, the intrinsic muscles were not very large, although they were regularly distributed throughout the pad. Rather, the extrinsic muscles, particularly the m. nasolabialis and m. maxillolabialis were large, deep and well-defined, running throughout the length of the mystacial pad. Therefore, we suggest that these extrinsic muscles, the m. nasolabialis and m. maxillolabialis, are responsible for driving vibrissal protraction underwater. These findings demonstrate the importance of three-dimensional visualisation techniques in advancing our understanding of mystacial anatomy and function in pinnipeds.

Evolutionary divergence of facial muscle physiology between domestic dogs and wolves.

Domestic dogs (Canis familiaris) are descended from gray wolf (Canis lupus) populations that inhabited Western Europe and Siberia. The specific timing of dog domestication is debated, but archeological and genetic evidence suggest that it was a multi-phase process that began at least 15,000 years ago. There are many morphological differences between dogs and wolves, including marked divergence in facial muscle morphology, but we know little about the comparative physiology of these muscles. A better understanding of comparative facial muscle physiology between domestic dogs and gray wolves would improve our conceptual framework for the processual mechanisms in dog domestication. To address these issues, we assessed the myosin profiles (type I and type II) from the zygomaticus and orbicularis oris muscles of 6 domestic dogs and 4 gray wolves. Due to small sample sizes, statistical analyses were not done. Results reveal that sampled domestic dogs have almost 100% fast-twitch (type II) muscle fibers while gray wolves have less than 50%, meaning that dog faces can contract fast while wolf faces are able to sustain facial muscle contraction. Sample sizes are limited but the present study indicates that dog domestication is associated with not only a change in facial muscle morphology but a concomitant change in how these muscles function physiologically. Selective pressures in the development of communication between dogs and humans using facial expression may have influenced this evolutionary divergence, but the paedomorphic retention of barking in adult dogs may have also played a role.

Tensile force impairs lip muscle regeneration under the regulation of interleukin-10.

Orbicularis oris muscle, the crucial muscle in speaking, facial expression and aesthetics, is considered the driving force for optimal lip repair. Impaired muscle regeneration remains the main culprit for unsatisfactory surgical outcomes. However, there is a lack of study on how different surgical manipulations affect lip muscle regeneration, limiting efforts to seek effective interventions. In this study, we established a rat lip surgery model where the orbicularis oris muscle was injured by manipulations including dissection, transection and stretch. The effect of each technique on muscle regeneration was examined by histological analysis of myogenesis and fibrogenesis. The impact of tensile force was further investigated by the in vitro application of mechanical strain on cultured myoblasts. Transcriptome profiling of muscle satellite cells from different surgical groups was performed to figure out the key factors mediating muscle fibrosis, followed by therapeutic intervention to improve muscle regeneration after lip surgeries. Evaluation of lip muscle regeneration till 56days after injury revealed that the stretch group resulted in the most severe muscle fibrosis (n=6, fibrotic area 48.9% in the stretch group, P<0.001, and 25.1% in the dissection group, P<0.001). There was the lowest number of Pax7-positive nuclei at Days 3 and 7 in the stretch group (n=6, P<0.001, P<0.001), indicating impaired satellite cell expansion. Myogenesis was impaired in both the transection and stretch groups, as evidenced by the delayed peak of centrally nucleated myofibers and embryonic MyHC. Meanwhile, the stretch group had the highest percentage of Pdgfra+ fibro-adipogenic progenitors infiltrated area at Days 3, 7 and 14 (n=6, P=0.003, P=0.006, P=0.037). Cultured rat lip muscle myoblasts exhibited impaired myotube formation and fusion capacity when exposed to a high magnitude (ε=2688μ strain) of mechanical strain (n=3, P=0.014, P=0.023). RNA-seq analysis of satellite cells isolated from different surgical groups demonstrated that interleukin-10 was the key regulator in muscle fibrosis. Administration of recombinant human Wnt7a, which can inhibit the expression of interleukin-10 in cultured satellite cells (n=3, P=0.041), exerted an ameliorating effect on orbicularis oris muscle fibrosis after stretching injury in surgical lip repair. Tensile force proved to be the most detrimental manoeuvre for post-operative lip muscle regeneration, despite its critical role in correcting lip and nose deformities. Adjunctive biotherapies to regulate the interleukin-10-mediated inflammatory process could facilitate lip muscle regeneration under conditions of high surgical tensile force.

Dynamic and static nasolabial muscle anatomy of unilateral cleft lip adult patients based on magnetic resonance imaging data.

This study aims to obtain a three-dimensional reconstruction model based on magnetic resonance imaging (MRI) data of patients with different degrees of unilateral cleft lip and analyze the anatomy and changes in multiple groups of nasolabial muscles under dynamic and static conditions. One normal person and four adult patients with unilateral cleft lip were included, and MRI was performed under static (upper and lower lips closed naturally) and dynamic (pout and grin) conditions. 3D Slicer software was used to reconstruct the model and draw the anatomic morphology of nasolabial muscles. The distance between the junction (where the muscle merges into the orbicularis oris) of the levator muscle, zygomaticminor muscle, and zygomatic major muscle to the median sagittal plane, the starting point to the junction point, the dynamic and static junction points, and the angle between the connection of dynamic and static junctions and the horizontal plane were measured under three kinds of movements, and the ratio was calculated. In all patients, under dynamic and static conditions, the distance from the muscle junction to the median sagittal plane, their ratios of the cleft side to the non-cleft side were all greater than 1. While the ratio of the distance from the starting point of the muscle to the junction point is less than 1. At static conditions, the two ratios of the same muscle increased gradiently with the severity of the cleft, and the ratio of the zygomatic minor muscle was prominent in the same patient. The ratio of the cleft side to the non-cleft side was greater than 1, and the value for comparison was the angle of the line from the static to the dynamic junction and the horizontal plane. The symmetry of the insertion site of the orbicularis oris and the linear distance of both sides of the muscle are related to muscle and cleft types. The angle of muscle contraction on the cleft side is greater than that on the non-cleft side.

Prévalence du réflexe de Charles Bell et évolution postopératoire dans la chirurgie du ptosis aponévrotique

Background: Ptosis surgery is common in oculoplastics, and its most threatening complication is corneal ulceration. Several factors have been associated with postoperative corneal disorders, such as the strength of the orbicularis muscle, the type of surgery performed, and theBell’s phenomenon reflex (BPR). The goal of this study was to investigate the prevalence of physiological BPR, absence of BPR, and presence of inverse BP in patients undergoing surgery for aponeurotic ptosis. The changes in the BPR during the postoperative course as well as the occurrence of corneal complications were also studied.Materials and Methods: A retrospective study was conducted at the University Hospital of Nice from January 2018 to December 2023. Patients operated on for aponeurotic ptosis were included. Patients with myogenic or neurogenic ptosis or with missing data were excluded. Data were recorded preoperatively and one month postoperatively and included: eyelid height, orbicularis muscle strength, prevalence of BPR, lack of BPR, inverse BPR, and postoperative corneal ulcer.Results: 98 eyelids of 57 patients were included over the study period. Preoperatively, the prevalence of physiological BPR, no BPR, and inverse BPR were 71.4%, 18.4%, and 10.2%, respectively. At one month postoperatively, 30.6% of patients experienced a change in BPR (p=0.004). The postoperative prevalence of BPR, no BPR, and inverse BPR were 77.5%, 17.4%, and 5.1%, respectively. The rate of postoperative corneal ulcers was 1.02%.Conclusion: Among patients operated on for aponeurotic ptosis, the prevalence of physiological BPR was 71.4% preoperatively. Approximately one-third of patients experienced a change in BPR one month postoperatively with a postoperative physiological BPR prevalence of 77.5%. The rate of corneal complications was low.

The other face of facioscapulohumeral muscular dystrophy: Exploring orofacial weakness using muscle ultrasound.

One of the most distinct clinical features of facioscapulohumeral muscular dystrophy (FSHD) is facial weakness. It leads to diminished facial expression and functional impairments. Despite its clinical relevance, little else is known about orofacial muscle involvement. We therefore evaluated orofacial muscle involvement in a sizeable cohort of FSHD participants with muscle ultrasound. Muscle ultrasound images of the following orofacial muscles were scored visually and quantitatively: depressor anguli oris (DAO), orbicularis oris (OO), buccinator, temporalis, masseter, digastric, zygomaticus major and minor bilaterally, and the geniohyoid. Reliability analyses of both visual and quantitative evaluations were performed. Ultrasound results were correlated with other measures: the FSHD clinical score, facial weakness score, and facial function scale. We included 107 FSHD participants (male 54%; age 52 ± 14 years), of whom 92% showed signs of facial weakness. The reliability of visual ultrasound analysis varied widely (κ 0.0-1.0). Quantitative ultrasound reliability was high (intraclass correlation analysis ≥ 0.96). The DAO, buccinator, OO, temporalis, and zygomaticus minor muscles were affected most often (15%-39%). The digastric, geniohyoid, zygomaticus major, and masseter muscles were least often affected (<5%). The ultrasound compound score correlated weakly to moderately with other outcome measures used (ρ = 0.3-0.7). This study adds to the understanding of orofacial weakness in FSHD, confirming the involvement of the muscles of facial expression in FSHD using ultrasound. We showed that orofacial muscle ultrasound is feasible and reliable when quantitatively assessed. Future studies should evaluate orofacial muscle ultrasound longitudinally, alongside clinical and patient-reported facial weakness outcome measures, to assess their potential as outcome measures.