Depressor Labii Inferioris Research Articles

Deciphering Depressor Anguli Oris for Lower Face Rejuvenation: A Prospective Ultrasound-based Investigation.

The depressor anguli oris muscle (DAO) is a pivotal treatment target when creating a harmonic jawline. However, evidence of its live morphology remains scarce. In this study we aimed to reevaluate the DAO with a facile ultrasound analysis and thereby guide safer and more effective botulinum toxin type A (BTX-A) injection. A prospective ultrasound assessment was conducted in 41 patients. Morphology of the DAO and its relative position to neighboring structures were appraised at the ubiquitous facial landmark, the labiomandibular fold (LMF). Three-dimensional images were captured before and after the patient received the BTX-A injection based on sonographic evidence. The skin-to-muscle depths of the DAO on average (measured from the medial to lateral border) were 5.26, 5.61, and 8.42 mm. The DAO becomes thinner and wider from zone 1 to zone 3 (P < .001). Overlapping lengths of the DAO and the depressor labii inferioris increased from zone 1 to zone 3: 4.74, 9.68, 14.54 mm (P < .001). The medial border of the DAO was located at 4.33, 6.12, 8.90 mm medial to the LMF (zone 1-3), and no muscle fibers of the DAO were observed in zone 1 or zone 2 in nearly one-third of patients. Improvement of the mouth corner downturn angle upon receiving BTX-A injection at zones 2 and 3 were 88.3%, 32.3%, and 14.7% for the neutral, maximum smile, and down-turning mouth corner expressions. This work established an informative ultrasound portrait of the DAO and structures in the perioral region, which suggested the LMF as a convenient landmark for locating the DAO. Injection at the middle and lower thirds of the LMF at a 4- to 5-mm depth is recommended.

Preoperative assessment of depressor anguli oris to prevent myectomy failure: An anatomical study using high-resolution ultrasound

Myectomies of the lower lip depressor muscles have unexplained high failure rates. This study aimed to examine the depressor anguli oris (DAO) muscle using high-resolution ultrasound to identify potential anatomical explanations for surgical failures and to determine the accuracy of utilizing preoperative ultrasound assessment to improve myectomies. Anatomical features of DAO and the surrounding anatomy were examined in 38 hemifaces of human body donors using high-resolution ultrasound and dissection. The ultrasound and dissection measurements showed the DAO muscle width to be 16.2±2.9 versus 14.5±2.5mm, respectively, and the location of the lateral muscle border 54.4±5.7 versus 52.3±5.4mm lateral to the midline. In 60% of the cases, the facial artery was either completely covered by lateral DAO muscle fibers or was found to be in direct contact with the lateral border. Significant muscle fiber continuity was present between the DAO and surrounding muscles in 5% of cases, whereas continuity between the depressor labii inferioris and surrounding muscles was considerably more common and pronounced. High-resolution ultrasound can accurately reveal important preoperative anatomical information in myectomies. Two potential explanations for the surgical failures were discovered: an overlap of lateral DAO muscle fibers over the facial artery could lead to inadequate resections and continuity with the surrounding muscles might lead to muscle function takeover despite adequate resections. Both can be uncovered preoperatively by the surgeon through a brief, directed ultrasound examination, which may allow for modification of the surgical plan to reduce surgical failure.

The Functional Anatomy and Innervation of the Platysma is Segmental: Implications for Lower Lip Dysfunction, Recurrent Platysmal Bands, and Surgical Rejuvenation.

Despite the central role of the platysma in face and neck rejuvenation, much confusion exists regarding its surgical anatomy. This study was undertaken to clarify the regional anatomy of the platysma and its innervation pattern and to explain clinical phenomena, such as the origin of platysmal bands and their recurrence, and the etiology of lower lip dysfunction after neck lift procedures. Fifty-five cadaver heads were studied (16 embalmed, 39 fresh, mean age 75 years). Following preliminary dissections and macro-sectioning, a series of standardized layered dissections were performed, complemented by histology and sheet plastination. In addition to its origin and insertion, the platysma is attached to the skin and deep fascia across its entire superficial and deep surfaces. This composite system explains the age-related formation of static platysmal bands, recurrent platysmal bands after complete platysma transection, and recurrent anterior neck laxity after no-release lifting. The facial part of the platysma is primarily innervated by the marginal mandibular branch of the facial nerve, whereas the submandibular platysma is innervated by the "first" cervical branches, which terminate at the mandibular origin of the depressor labii inferioris. This pattern has implications for postoperative dysfunction of the lower lip, including pseudoparalysis, and potential targeted surgical denervation. This anatomical study, comprised of layered dissections, large histology, and sheet plastination, fully describes the anatomy of the platysma including its bony, fascial, and dermal attachments, as well as its segmental innervation including its nerve danger zones. It provides a sound anatomical basis for the further development of surgical techniques to rejuvenate the neck with prevention of recurrent platysmal banding.

Lower Facial Nerve Nomenclature Clarification: Cervical Branch Controls Smile-Associated Lower Lip Depression and Dental Display.

In head and neck ablative surgery, traditional teaching is that the key facial nerve branch to preserve along the plane of the lower border of the mandible is the marginal mandibular branch (MMb), which is considered to control all lower lip musculature. The depressor labii inferioris (DLI) is the muscle responsible for pleasing lower lip displacement and lower dental display during natural emotive smiling. To understand the structure/function relationships of the distal lower facial nerve branches and lower lip musculature. In vivo extensive facial nerve dissections under general anesthesia. Intraoperative mapping was performed in 60 cases, using branch stimulation and simultaneous movement videography. In nearly all cases, the MMb innervated the depressor anguli oris, lower orbicularis oris, and mentalis muscles. The nerve branches controlling DLI function were identified 2 ± 0.5 cm below the angle of the mandible, originating from a cervical branch, separately and inferior to MMb. In half of the cases, we identified at least 2 independent branches activating the DLI, both within the cervical region. An appreciation of this anatomical finding may help prevent lower lip weakness following neck surgery. Avoiding the functional and cosmetic consequences that accompany loss of DLI function would have a significant impact on the burden of potentially preventable sequelae that the head and neck surgical patient frequently carries.

Novel anatomical proposal for botulinum neurotoxin injection targeting depressor anguli oris for treating drooping mouth corner.

The depressor anguli oris (DAO) muscle is a thin, superficial muscle located below the corner of the mouth. It is the target for botulinum neurotoxin (BoNT) injection therapy, aimed at treating drooping mouth corners. Hyperactivity of the DAO muscle can lead to a sad, tired, or angry appearance in some patients. However, it is difficult to inject BoNT into the DAO muscle because its medial border overlaps with the depressor labii inferioris and its lateral border is adjacent to the risorius, zygomaticus major, and platysma muscles. Moreover, a lack of knowledge of the anatomy of the DAO muscle and the properties of BoNT can lead to side effects, such as asymmetrical smiles. Anatomical-based injection sites were provided for the DAO muscle, and the proper injection technique was reviewed. We proposed optimal injection sites based on the external anatomical landmarks of the face. The aim of these guidelines is to standardize the procedure and maximize the effects of BoNT injections while minimizing adverse events, all by reducing the dose unit and injection points.

Unreported anomalous musculature of first pharyngeal arch

Musculature of first pharyngeal arch play an important role in mastication, speech and swallowing thus a comprehensive knowledge of anatomical variations will be important for surgeons and Traumatologists which can increase the success of diagnostic evaluation and surgical approaches to the region. Accordingly, the purpose of this study was designed to evaluate the prevalence of anomalous musculature of first pharyngeal arch in the human cadavers. This study was carried out on 107 formalin embalmed human cadavers (male 62 and 45 female), and dissections were performed in accordance with the institutional ethical standards and Indian anatomy act. Out of 107 cadavers, in three cadavers the following rare unreported muscular variations of first pharyngeal arch were encountered in the present study: 1. Rare and unusual unilateral quadrilateral anomalous muscle in the submandibular region superficial to the submandibular gland with an accessory head of depressor labii inferioris muscle; 2. Anomalous unilateral facial muscle extending from the from the right lateral angle of mouth to coronoid process of mandible; and 3. An anomalous accessory head of temporalis muscle extending from the temporalis tendon to the posterior part of buccinator muscle.

The Advantages of Applying a 5-mm Endoscope in the Transoral Endoscopic Thyroidectomy Vestibular Approach.

We sought to compare the effect of applying a 5-mm endoscope and a 10-mm endoscope in the transoral endoscopic thyroidectomy vestibular approach (TOETVA) and to clarify the advantages of using a 5-mm endoscope. A retrospective analysis of the clinical data of 135 patients who were diagnosed with papillary thyroid carcinoma and who had undergone TOETVA in the thyroid disease center of The First Affiliated Hospital of Nanchang University between January 2019 and May 2020 was performed. Among the included patients, a 10-mm endoscope was used in 50 cases (the 10-mm endoscope group) and a 5-mm endoscope was used in 85 cases (the 5-mm endoscope group), respectively. Operative trauma, operative parameters, postoperative complications, and postoperative mandibular sensation score were compared and analyzed. Compared with the 10-mm endoscope group, the 5-mm endoscope group had less surgical trauma, less injury to the mandibular muscles (orbicularis oris, depressor labii inferioris, and mentalis muscle), shorter operative times (107.7±8.1 vs. 121.3±11.6 min, P<0.01), less intraoperative bleeding (14.3±4.8 vs. 17.9±5.3 mL, P<0.01), no obvious postoperative complications, lower mandibular sensation score values (5.7±0.6 vs. 6.0±0.4 points, P<0.01), and shorter mandibular recovery times (9.4±2.5 vs. 12.3±3.6 d, P<0.01). The application of a 5-mm endoscope not only improves the cosmetic effect of TOETVA but also reduces the degree of surgical trauma, saves the surgical space, improves the surgical efficiency, and reduces postoperative discomfort, with a promising application prospect.

Botulinum Toxin Type A Injection in the Treatment of Postparetic Facial Synkinesis: An Integrative Review.

This study aimed to review the recent literature about botulinum toxin type A treatment patterns, including muscle targets, doses, duration of effect, adverse effects, and clinical outcomes in patients with postparetic synkinesis. A bibliographic research of studies published in the last 10 yrs was carried out on PubMed database, using the medical subject heading terms: botulinum toxin and synkinesis. English-language cohort studies or randomized controlled trials about botulinum toxin type A treatment on patients with postparetic synkinesis were eligible for inclusion. Ten studies met the inclusion criteria, seven prospective studies, two retrospective studies, and one randomized controlled trial, involving 23-99 patients. The target facial muscles included frontalis, corrugator supercilli, orbicularis oculi, levator labii superioris, zygomaticus major, orbicularis oris, risorius, buccinator, depressor anguli oris, depressor labii inferioris, mentalis, and platysma. The dose of onabotulinumtoxinA administered per injection site ranged between 0.5 and 10 U. Adverse effects were rare and temporary. The mean duration of onabotulinumtoxinA effect ranges from 66 days to 4 mos. There was a statistically significant improvement in posttreatment evaluation, both in objective and subjective assessments. There is scientific evidence of the benefit of botulinum toxin type A treatment for postparetic synkinesis, but there is lack of standardized treatment protocols.

Advances and future directions in the care of patients with facial paralysis

Advances and future directions in the care of patients with facial paralysis

A Retrospective and Anatomical Study Describing the Injection of Botulinum Neurotoxins in the Depressor Anguli Oris.

The depressor anguli oris acts to lower the lateral corners of the mouth and can cause an individual to appear sad or angry and contribute to the development of the labiomental folds. Many patients can benefit from the injection of small amounts of botulinum neurotoxin into the depressor anguli oris to enable the lip elevators to reposition the corners of the mouth. Although effective, the procedure is off-label, and the proximity of the depressor anguli oris to the depressor labii inferioris, particularly inferiorly, can lead to inadvertent treatment of the latter, resulting in lip asymmetry. The authors have taken a threefold approach to establish a depressor anguli oris injection technique that provides optimal aesthetic outcomes with a low incidence of adverse events. This involved, first, reviewing the limited existing literature for studies discussing depressor anguli oris anatomy and botulinum neurotoxin treatment technique; second, supplementing information from the published literature with information from cadaver dissections to demonstrate the relationship between the depressor anguli oris and surrounding anatomical structures; and third, performing a retrospective chart review of 275 patients treated with the authors' three-point injection technique. Combining data from published studies, cadaver dissections, and clinical experience, the authors demonstrate that a three-point technique performed in the upper half of the depressor anguli oris is associated with good clinical outcome and avoids common side effects related to injection or spread of neurotoxin to adjacent muscles. Therapeutic, IV.

Stabilisation et réanimation de la lèvre inférieure paralysée. Étude rétrospective de 66 cas et revue de la littérature. Proposition d’un algorithme décisionnel

Several techniques for the stabilization and the reanimation of the paralyzed lower lip have been proposed, sometimes combined but the authors are rather vague. Thanks to our cases and a literature review, we suggest an algorithm. Sixty-six patients haven been reviewed. The static and dynamic clinical evaluation have been done thanks to the study of the medical files, photographs and videos samples. The different techniques we have used were: (a) botulinum toxin in the contralateral depressor labii inferioris (DLI) (n=66), contralateral DLI myectomy (n=1); (b) a strip of fascia lata (n=16) either combined with a lengthening temporalis myoplasty (MAT) (n=10) or only realizing a passive suspension thanks to one vector (n=4), or a passive suspension with two strips (n=2); (c) digastric muscle transfer (n=4). When the elevator muscles are sounds, botulin toxin (± myectomy) is proposed if the lower lip is not inverted. Otherwise, a suspension thanks to a digastric muscle transfer or a passive suspension with a horizontal and a vertical strips are recommended. If the elevator muscles are no more operational, a MAT with a passive suspension with one vector is considerated and if the lower lip is inverted, a digastric muscle transfer with a fascia lata strip or a MAT with two strips is proposed. This algorithm submission allows to refine the treatment of the stabilization and the reanimation of the lower lip.

The neuropathy of marginal mandibular branch of the facial nerve

To analyze the diagnosis, treatment and rehabiltation of patients with marginal mandibular branch of the facial nerve (MMB). We have collected 6 patients (mean age 40 [33.8; 44] years) with isolated lesion of MMB that innervates the depressor labii inferioris and chin muscle. The illness duration without any improvement was 35 [13; 44] days. Diagnosis and treatment were carried out according to the special algorithm developed and implemented at the N.V. Sklifosovsky Research Institute of Emergency Medicine. With needle myography of the muscle that lowers the lower lip, the change in the ratio of the maximum amplitudes of the interference pattern (MAIP) in all patients exceeded 15%, and in 2 cases it was more than 90%. Comparing with the healthy face side, a change of the MAIP ratio less than 90% was considered as the biomarker of favorable prognosis, with conservative treatment recommendations, e.g. the set of exercises with targeted effects on depressor labii inferioris. With regular exercises, patients noted positive dynamics of restoring the symmetry of the smile in 1-2 months of the disease, full recovery - in 4-5 months. In case of exercises rejection, there was no positive dynamics. A change in the MAIP ratio more than 90% or the absence of motor unit potentials was considered as the biomarker of an unfavorable outcome and an indication for surgical treatment. After surgical treatment, the improvement occurred within 4-5 months. In conservative treatment group, there were no positive changes even with regular exercises. The diagnosis of an isolated lesion of MMB is established clinically using a protocol of step-by-step assessment of facial muscle function, and tactics is determined by needle myography with depressor labii inferioris. Even with favorable myographic predictors, spontaneous recovery may not occur, exercises with a targeted effect on the depressor labii inferioris are required, and in the presence of unfavorable predictors, surgical treatment is reccomended.

Impact of Hayes Martin Maneuver and Anterograde Dissection on Identification and Preservation of Marginal Mandibular Nerve during Neck Dissection in Patients with Oral Squamous Cell Carcinoma

Background: Hayes Martin maneuver (HMM) and Anterograde dissection technique (ADT) were originally described in 1951 as a means of preserving the marginal mandibular nerve (MMN) during level 1B clearance in a neck dissection procedure address the cervical metastasis in patients with oral squamous cell carcinomas.&#x0D; Objectives: To compare and evaluate the efficacy of HMM and ADT in preservation of MMN using Electromyography of muscles supplied by the nerve ie Mentalis, Depressor labii inferioris and depressor anguli oris, to evaluate muscle function.&#x0D; Methodology: 20 patients undergoing neck dissection over a period of 6 months grouped were into two groups (10 patients for Hayes Martin manoeuvre and 10 patients for anterograde dissection technique) calculated by purposive sampling method. Postoperative Electromyography and assessment of nerve function using House and Brackmann grading was done on day 5,15 and 30.&#x0D; Expected Results: HMM proves to be a less time consuming technique than Anterograde dissection by a significant margin considering perifacial node clearance and level 1B clearance. Anterograde dissection technique proved to be more effective than Hayes Martin Maneuver for preservation of MMN as average neuromuscular electrical activity in anterograde dissection cases was higher than the average of HMM cases. Although, no significant statistical difference was found when the neural function was compared on a house and brackmann grading scale&#x0D; Conclusion: Anterograde dissection technique is technique sensitive, relatively time consuming and requires a higher surgical operator skill. However, provides statistically proven better results in terms of neural electric activity and post-operative functional neural deficit in the operated subjects.

Depressor Anguli Oris Myectomy versus Transfer to Depressor Labii Inferioris for Facial Symmetry in Synkinetic Facial Paralysis.

Postparalytic synkinesis presents with a combination of hypo- and hypertonic muscles, leading to facial asynchrony with animation and at rest. One ubiquitous finding is a hypertonic depressor anguli oris (DAO) muscle and a weak depressor labii inferioris (DLI) muscle. The goal of this study was to evaluate the utility of DAO myectomy with or without its transfer to the weakened DLI in improving critical components of the dynamic smile. From 2018 to 2020, this single-center, prospective study included of postparetic facial synkinetic patients with evidence of DAO hypertonicity who underwent DAO myectomy with or without transfer to DLI. Objective facial measurements were used to compare the effectiveness of DAO to DLI transfer to pure DAO myectomy in improving asymmetry of the synkinetic hemiface. Twenty-one patients with unilateral postparetic facial synkinesis with DAO hypertonicity were included; 11 underwent DAO myectomy, while 10 underwent DAO to DLI transfer. Baseline demographics and facial measurements were similar between the groups. DAO myectomy resulted in increased modiolus resting position, closed-mouth smile modiolus angle and excursion, open-mouth smile modiolus angle, excursion, dental show, and decreased lower lip height deviation. DAO to DLI transfer demonstrated similar findings but lacked significant increase in excursion and resulted in worsened lower lip height deviation. These findings illustrate the utility of DAO myectomy in improving imbalance in the synkinetic patient and necessitate further technical refinements for DAO transfers or a different approach for improving lower lip depression in this subgroup of patients.

Anatomical Features in Lower-Lip Depressor Muscles for Optimization of Myectomies in Marginal Mandibular Nerve Palsy.

Myectomies of the lower-lip depressor muscles, with the aim to improve facial balance in unilateral facial paralysis, have unexplained high recurrence rates. A potential explanation is that these recurrences are due to inadequate resection through the muscle width, leaving lateral muscle fibers intact. Revisit the anatomy of the lower-lip depressor muscles and suggest an optimization of the surgical technique. Perform a literature review to identify recurrence rates and surgical technique of the procedure. Ten fresh hemifaces were dissected. The following measurements of depressor labii inferioris and depressor anguli oris were made: the widths of the muscles, the distance from the mandibular midline to the lateral borders of the muscles, and the intraoral distance from the lateral canine to the lateral border of depressor anguli oris. A literature review was performed. The width of depressor labii inferioris was 20 ± 4 mm and depressor anguli oris 14 ± 3 mm. The distance from the midline to the lateral border of depressor labii inferioris was 32 ± 4 mm and 54 ± 4 mm for depressor anguli oris. The literature review revealed a mean recurrence rate of 21%. A potential optimization of the surgical technique in lower-lip depressor myectomies is to extend the muscle resection laterally. To ensure inclusion of the whole width of the depressor muscles and decrease the recurrence rates of the procedure, the measurements presented in this study should be kept in mind during surgery.

Topographic and Neural Anatomy of the Depressor Anguli Oris Muscle and Implications for Treatment of Synkinetic Facial Paralysis.

Synkinetic patients often fail to produce a satisfactory smile because of antagonistic action of a hypertonic depressor anguli oris muscle and concomitantly weak depressor labii inferioris muscle. This study investigated their neurovascular anatomy to partially explain this paradoxical depressor anguli oris hypertonicity and depressor labii inferioris hypotonicity and delineated consistent anatomical landmarks to assist in depressor anguli oris muscle injection and myectomy. Ten hemifaces from five fresh human cadavers were dissected to delineate the neurovascular supply of the depressor anguli oris and depressor labii inferioris muscles in addition to the depressor anguli oris muscle relation to consistent anatomical landmarks. The depressor anguli oris muscle received innervation from both lower buccal and marginal mandibular facial nerve branches, whereas the depressor labii inferioris muscle was solely innervated by marginal mandibular branches. The mandibular depressor anguli oris origin was on average 39 mm wide, and its medial and lateral borders were located 17 mm from the symphysis and 41 mm from the mandibular angle, respectively. The depressor anguli oris fibers consistently passed anterior to the first mandibular molar toward their insertion into the modiolus, which was located 10 mm lateral and 10 mm caudal to the oral commissure. Depressor anguli oris muscle dual innervation versus depressor labii inferioris single innervation may explain why depressor anguli oris hypertonicity and depressor labii inferioris weakness are commonly observed concomitantly in synkinetic patients. Based on treatment goals, diagnostic percutaneous injection with lidocaine can be performed on the depressor anguli oris muscle along a cutaneous line from the modiolus to the mandibular first molar border, and an intraoral depressor anguli oris myectomy can be performed along that same transmucosal line.

An unusual adverse event of botulinum toxin injection in the lower face

In the lower third of the face, botulinum toxin A is used to obtain a more harmonious contour. The anatomical complexity of the face requires a more precise application of botulinum toxin. Describe the treatment of an unexpected effect after botulinum toxin A application in the lower third of the face. A 51-year-old female patient presented to our clinic for application of botulin toxin aiming to improve facial wrinkles and contour. 50U of botulinum toxin type A were applied to the upper third and 20U to the lower third of the face. The patient returned after 10days with a smile asymmetry and an excessive and unconscious lowering on the right side of the lower lip while laughing. So, 3U of botulinum toxin were applied to the center of the depressor labii inferioris muscle on the right side. The patient returned with a satisfactory correction of the smile asymmetry. Although treatments with botulinum toxin A are considered safe, unexpected results can occur. In our case, it probably occurred due to medial injection or diffusion of botulinum toxin A into depressor anguli oris muscle on the left side that may lead to paralysis of the left depressor labii inferioris muscle and downward hyperfunction of the unaffected right lower lip. The correction was made with a new injection of botulinum toxin A in the depressor labii inferioris hyperactive muscle at the right side.

Synkinetic Unilateral Lower Lip Palsy: Diagnosis and Technical Considerations for Facial Reanimation.

Importance: There are no universally adopted surgical techniques to treat depressor labii inferioris (DLI) dysfunction in patients with postfacial paralysis synkinesis. We describe a novel description of this disorder and technical surgical considerations for reanimation. Objective: To describe a new classification for DLI dysfunction and a surgical option to restore a natural appearing full dentition smile. Design: Surgical pearls-description of novel surgical technique. Setting: A private practice. Participants: Patients who underwent the operation.

Preoperative Localization of the Carotid Bifurcation for Cervical Carotid Exposure Using the Mastoid-Hyoid Line.

Background and Importance:The location of the carotid bifurcation (CB) is highly variable, which makes precise exposure of the cervical carotid artery difficult, especially in transverse incisions. The method for preoperative localization of the CB is not well established. We used the distance from the mastoid-hyoid (M-H) line to the CB, measured preoperatively with computed tomography angiography, to localize the location of the transverse skin incision. We describe and evaluate the accuracy of a method for preoperative localization of the CB for cervical carotid exposure.Methods:The researchers retrospectively evaluated 16 patients with aneurysms arising from the internal carotid artery (ICA) who had received cervical carotid exposure using the localization method of incision and were retrospectively evaluated from February 2018 to November 2019. The method of measurement and localization of the skin incision are described, and two illustrative cases are demonstrated.Results:Saccular aneurysms of the ophthalmic (C2) segment and communicating (C1) segment of the ICA were found in 8 and 8 patients, respectively. Nine patients had left-sided exposure, and 7 patients had right-sided exposure. The mean distance from the M-H line to the CB was 2.1 cm (range 0.5–3.5 cm). The accuracy of this method was 93.8%. No paralysis of the depressor anguli oris or the depressor labii inferioris was found postoperatively.Conclusion:The distance from the M-H line to the CB can be used to estimate transverse skin incisions for cervical carotid exposure.

Contralateral Depressor Labii Inferioris Chemodenervation for Congenital Unilateral Lower Lip Palsy.

Congenital unilateral lower lip palsy - also known as asymmetric crying facies - is isolated asymmetry of the lower lip unilaterally. It is characterized by isolated lower lip asymmetry during smiling and speech. Although etiology is unknown, depressor labii inferioris (DLI) weakness is hold responsible. Purpose of this study was to evaluate the effectiveness of contralateral depressor labii inferioris botulinum toxin injection on patients' concern levels and patient satisfaction. Ten units of botulinum toxin A injection was carried out to the healthy contralateral side. Eleven patients were treated. Patients' pretreatment and posttreatment concern regarding asymmetry during speech and smiling was evaluated with a questionnaire. Patients' perception of treatment satisfaction was also evaluated with a questionnaire. Mean score related to concern about asymmetric appearance during smiling decreased from 1.6 ± 0.8 to 0.5 ± 0.5. Mean score related to concern about asymmetric appearance during speech decreased from 1.6 ± 0.5 to 0.4 ± 0.5. Eleven out of 11 patients reported improvement with speech whereas 10 out of 11 patients reported improvement with smiling. No weakness about oral competence was reported. Most congenital unilateral lower lip palsy patients are concerned regarding their asymmetric appearance while smiling or speaking. Chemodenervation of the contralateral DLI muscle reduces concern levels and has high patient satisfaction. Chemodenervation of the contralateral healthy DLI muscle is a valid, practical treatment option.