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BACKGROUND: 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. METHODS: Anatomical features of DAO and the surrounding anatomy were examined in 38 hemifaces of human body donors using high-resolution ultrasound and dissection. RESULTS: The ultrasound and dissection measurements showed the DAO muscle width to be 16.2 ± 2.9 versus 14.5 ± 2.5 mm, respectively, and the location of the lateral muscle border 54.4 ± 5.7 versus 52.3 ± 5.4 mm 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. CONCLUSIONS: 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.
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Músculos Faciales , Labio , Humanos , DisecciónRESUMEN
BACKGROUND: Botulinum toxin injection is the accepted standard treatment for synkinesis and gustatory hyperlacrimation in patients with facial paralysis. However, poor injection accuracy can result in inconsistent treatment outcomes, variable treatment durations, and complications. Ultrasound guidance should increase injection accuracy in the facial region; however, this has not been proven. METHODS: Twenty-six hemifaces of nonembalmed cadavers were studied in a randomized split-face manner. Ink was injected with ultrasound or landmark guidance into the lacrimal gland and three common synkinetic muscles: the orbicularis oculi, depressor anguli oris, and mentalis. Injection accuracy was evaluated using several measures. RESULTS: Using ultrasound guidance, most ink (>50%) was found inside the correct target in 88% of cases, compared with 50% using landmark guidance ( P < 0.001). This was most pronounced in the lacrimal gland (62% versus 8%), depressor anguli oris (100% versus 46%), and mentalis (100% versus 54%) ( P < 0.05). All ink was found inside the correct target (no ink outside) in 65% using ultrasound guidance versus 29% without ( P < 0.001). Injection accuracy (any ink in target) was 100% when using ultrasound guidance versus 83% without ( P < 0.01). Twenty-three percent of the landmark-guided depressor anguli oris injections stained the facial artery ( P = 0.22). CONCLUSIONS: Ultrasound guidance significantly increased injection accuracy and reduced the amount of ink lost in the surrounding tissue compared with landmark guidance. Clinical trials are needed to explore the effects of ultrasound guidance on treatment outcome, duration, and complications in patients with facial paralysis.
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Toxinas Botulínicas Tipo A , Parálisis Facial , Humanos , Parálisis Facial/diagnóstico por imagen , Parálisis Facial/tratamiento farmacológico , Inyecciones , Músculos Faciales , Resultado del Tratamiento , Ultrasonografía IntervencionalRESUMEN
Osteoradionecrosis (ORN) manifested as symptomatic nonunion between primary free flap and native mandible after primary bony reconstruction of the mandible is an entity not included in current conventional ORN staging guidelines. This article reports on and proposes early management of this debilitating condition using a chimeric scapular tip free flap (STFF). Methods: A retrospective review was performed examining cases with bony nonunion at the junction of primary free fibula flap (FFF) and native mandible at a single center over a 10-year duration, which required a second free bone flap. Details of each case (patient demographics, oncological details, primary surgery, presentation, and secondary surgery) were documented and analyzed. Outcomes of the treatment were assessed. Results: Four patients (two men and two women; age range, 42-73 years) out of a total of 46 primary FFF were identified. All patients presented with symptoms of low-grade ORN and radiological signs of nonunion. All cases were reconstructed with chimeric STFF. The duration of follow-up ranged from 5 to 20 months. All patients reported resolution of symptoms and radiological evidence of union. Two of four patients subsequently received osseointegrated dental implants. Conclusions: Institutional rate of nonunion after primary FFF requiring a second free bone flap is 8.7%. All the patients of this cohort presented with a similar clinical entity easily discounted as an infected nonunion postosseous flap reconstruction. There is no ORN grading system that currently guides the management of this cohort. Good outcomes are possible with early surgical intervention with a chimeric STFF.
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BACKGROUND: Donor nerve options for lower lip reanimation are limited in patients undergoing oncological resection of the facial nerve. The ansa cervicalis nerve (ACN) is an advantageously situated donor with great potential but has not been examined in detail. In the current study, the anatomical technical feasibility of selective ACN to marginal mandibular nerve (MMN) transfer for restoration of lower lip tone and symmetry was explored. A clinical case is presented. METHODS: Dissections were conducted in 21 hemifaces in non-embalmed human cadavers. The maximal harvestable length of ACN was measured and transfer to MMN was simulated. A 28-year-old male underwent ACN-MMN transfer after parotidectomy (carcinoma) and was evaluated 12 months post-operatively (modified Terzis' Lower Lip Grading Scale [25 observers] and photogrammetry). RESULTS: The harvestable length of ACN was 100 ± 12 mm. A clinically significant anatomical variant ("short ansa") was present in 33% of cases (length: 37 ± 12 mm). Tensionless coaptation was possible in all cases only when using a modification of the surgical technique in "short ansa" cases (using an infrahyoid muscle nerve branch as an extension). The post-operative course of the clinical case was uneventful without complications, with improvement in tone, symmetry, and function at the lower lip at 12-month post-operative follow-up. CONCLUSIONS: Selective ACN-MMN nerve transfer is anatomically feasible in facial paralysis following oncological ablative procedures. It allows direct nerve coaptation without significant donor site morbidity. The clinical case showed good outcomes 12 months post-operatively. A strategy when encountering the "short ansa" anatomical variant in clinical cases is proposed.
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Parálisis Facial , Transferencia de Nervios , Masculino , Humanos , Adulto , Nervio Facial/cirugía , Transferencia de Nervios/métodos , Labio , Parálisis Facial/cirugía , Cadáver , Nervio MandibularRESUMEN
INTRODUCTION: 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. AIM: 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. MATERIALS AND METHODS: 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. RESULTS: The width of depressor labii inferioris was 20â±â4âmm and depressor anguli oris 14â±â3âmm. The distance from the midline to the lateral border of depressor labii inferioris was 32â±â4âmm and 54â±â4âmm for depressor anguli oris. The literature review revealed a mean recurrence rate of 21%. DISCUSSION: 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.