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

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 20 ±â€Š4 mm and depressor anguli oris 14 ±â€Š3 mm. The distance from the midline to the lateral border of depressor labii inferioris was 32 ±â€Š4 mm and 54 ±â€Š4 mm 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.

A full-thickness chemical burn to the hand using formic acid-based anti-wart treatment: a case report and literature review.

INTRODUCTION: Chemical burns are comparably rare but often result in full-thickness skin defects with frequent involvement of underlying structures. Hands are the most commonly affected injury site and impaired functional outcome is common. We present a case of an unusual chemical burn to the dorsum of the hand of a child secondary to application of a topical anti-wart treatment containing formic acid. CASE REPORT: An 11-year-old girl was referred to our outpatient department with a full-thickness injury resulting from a chemical burn having used a topical formic acid solution in the treatment of common warts. On examination, a 20-mm circular full-thickness defect was noted to the dorsum of the hand. The extensor tendons were not involved and there were no signs of infection. She required surgical debridement and local flap coverage. The postoperative recovery was unremarkable. CONCLUSION: Through a comprehensive literature review, four common topical solutions used in anti-wart treatment were identified to be associated with burns. Together with our case, this highlights the importance of careful patient education in the usage of common topical over-the-counter treatments.

Oculo-zygomatic nerve transfer for facial synkinesis: An anatomical feasibility study.

BACKGROUND: Patients with severe oro-ocular synkinesis often present with concomitant inefficient smile excursion on the affected site. In theory, oculo-zygomatic nerve transfer may decrease synkinesis and improve smile by redirecting nerve fibers to their target muscle. The aim of this study was to explore the feasibility of nerve transfer in human cadavers between a caudal branch innervating the orbicularis oculi to a cephalad branch innervating the zygomaticus major muscles. METHODS: Eighteen hemi-faces were dissected. Reach for direct coaptation of a caudal nerve branch innervating the orbicularis oculi muscle to a cephalad nerve branch innervating the zygomaticus major muscle was assessed. Measurements included total number of nerve branches as well as maximum dissection length. Nerve samples were taken from both branches at the site of coaptation and histomorphometric analysis for axonal count was performed. RESULTS: The number of sub-branches to the orbicularis oculi muscle was 3.1 ± 1.0 and to the zygomaticus major muscle 4.7 ± 1.2. The maximal length of dissection of the caudal nerve branch to the orbicularis oculi muscle was 28.3 ± 7.3 mm and for the cranial nerve branch to the zygomaticus major muscle 23.8 ± 6.5 mm. Transection and tension-free coaptation was possible in all cases but one. The average myelinated fiber counts per mm2 was of 5,173 ± 2,293 for the caudal orbicularis oculi branch and 5,256 ± 1,774 for the cephalad zygomaticus major branch. CONCLUSION: Oculo-zygomatic nerve transfer is an anatomically feasible procedure. The clinical value of this procedure, however, remains to be proven.

Cranial Nerve Coactivation and Implication for Nerve Transfers to the Facial Nerve.

In reanimation surgery, effortless smile can be achieved by a nonfacial donor nerve. The underlying mechanisms for this smile development, and which is the best nonfacial neurotizer, need further clarification. The aim of the present study was therefore to further explore the natural coactivation between facial mimic muscles and muscles innervated by the most common donor nerves used in smile reanimation. The study was conducted in 10 healthy adults. Correlation between voluntary facial muscle movements and simultaneous electromyographic activity in muscles innervated by the masseter, hypoglossal, and spinal accessory nerves was assessed. The association between voluntary movements in the latter muscles and simultaneous electromyographic activity in facial muscles was also studied. Smile coactivated the masseter and tongue muscles equally. During the seven mimic movements, the masseter muscle had fewer electromyographically measured coactivations compared with the tongue (two of seven versus five of seven). The trapezius muscle demonstrated no coactivation during mimic movements. Movements of the masseter, tongue, and trapezius muscles induced electromyographically recorded coactivation in the facial muscles. Bite resulted in the strongest coactivation of the zygomaticus major muscle. The authors demonstrated coactivation between voluntary smile and the masseter and tongue muscles. During voluntary bite, strong coactivation of the zygomaticus major muscle was noted. The narrower coactivation pattern in the masseter muscle may be advantageous for central relearning and the development of a spontaneous smile. The strong coactivation between the masseter muscle and the zygomaticus major indicates that the masseter nerve may be preferred in smile reanimation.

Platysma Motor Nerve Transfer for Restoring Marginal Mandibular Nerve Function.

BACKGROUND: Injuries of the marginal mandibular nerve (MMN) of the facial nerve result in paralysis of the lower lip muscle depressors and an asymmetrical smile. Nerve reconstruction, when possible, is the method of choice; however, in cases of long nerve gaps or delayed nerve reconstruction, conventional nerve repairs may be difficult to perform or may provide suboptimal outcomes. Herein, we investigate the anatomical technical feasibility of transfer of the platysma motor nerve (PMN) to the MMN for restoration of lower lip function, and we present a clinical case where this nerve transfer was successfully performed. METHODS: Ten adult fresh cadavers were dissected. Measurements included the number of MMN and PMN branches, the maximal length of dissection of the PMN from the parotid, and the distance from the anterior border of the parotid to the facial artery. The PMN reach for direct coaptation to the MMN at the level of the crossing with the facial artery was assessed. We performed histomorphometric analysis of the MMN and PMN branches. RESULTS: The anatomy of the MMN and PMN was consistent in all dissections, with an average number of subbranches of 1.5 for the MMN and 1.2 for the PMN. The average maximal length of dissection of the PMN was 46.5 mm, and in every case, tension-free coaptation with the MMN was possible. Histomorphometric analysis demonstrated that the MMN contained an average of 3,866 myelinated fiber counts per millimeter, and the PMN contained 5,025. After a 3-year follow-up of the clinical case, complete recovery of MMN function was observed, without the need of central relearning and without functional or aesthetic impairment resulting from denervation of the platysma muscle. CONCLUSIONS: PMN to MMN transfer is an anatomically feasible procedure for reconstruction of isolated MMN injuries. In our patient, by direct nerve coaptation, a faster and full recovery of lower lip muscle depressors was achieved without the need of central relearning because of the synergistic functions of the PMN and MMN functions and minimal donor-site morbidity.

Use of a pedicled fillet foot flap for knee preservation in severe lower extremity trauma: A case report and literature review.

We report the sequential use of a pedicled fillet foot flap in a clinical case of complex bilateral lower extremity trauma to achieve stable wound closure, maximizing length preservation and gait rehabilitation. In addition, we perform a literature review of the use of fillet foot flaps in lower extremity trauma.