The synkinetic mentalis muscle and its negative effect on the smile: pathomechanism and treatment with mentalis targeted selective neurectomies.

BACKGROUND: The treatment of post-paretic facial synkinesis is based on a combination of nonsurgical and surgical strategies. Even if improvements towards the restoration of a natural smile have been obtained with selective neurectomies (SN) and depressor anguli oris (DAO) myectomy, the lower lip frequently remains asymmetric and cranially displaced. The aim of this study was to evaluate the effect of the mentalis muscle on the position and symmetry of the lower lip in patients with synkinesis and to assess the added benefit of neurectomies of nerves innervating the mentalis muscle in improving the lower lip configuration and mandibular teeth show. METHODS: A retrospective cohort study on all patients affected by post-paretic synkinesis at our Institution was performed. A Non-mentalis Neurectomy Group including twelve patients treated with SN without targeting the branches to mentalis muscle was compared to a Mentalis Neurectomy Group, including sixteen patients who underwent additional specific mentalis branches neurectomies. All patients underwent DAO myectomy. Analyses of standardized images were performed with ImageJ software. RESULTS: Post-operative comparisons between the two groups showed superior and significant improvements in the Mentalis Neurectomy Group across all measures, including lower and upper border deviation (p=0.035 and p=.004, respectively), inclination of the lower lip (p=.019), and lower quadrant dental show (p=.004). CONCLUSIONS: The addition of targeted selective neurectomies to the branches innervating mentalis muscle significantly improved dental show and caudal position and symmetry of the lower lip during open mouth smile.

Effect of Lower Extremity Nerve Decompression in Patients With Painful Diabetic Peripheral Neuropathy: The Diabetic Neuropathy Nerve Decompression Randomized, Observation Group and Placebo Surgery-Controlled Clinical Trial.

OBJECTIVE: To evaluate the effect of nerve decompression on pain in patients with lower extremity painful diabetic peripheral neuropathy (DPN). BACKGROUND: Currently, no treatment provides lasting relief for patients with DPN. The benefits of nerve decompression remain inconclusive. METHODS: This double-blinded, observation and same-patient sham surgery-controlled randomized trial enrolled patients aged 18 to 80 years with lower extremity painful DPN who failed 1 year of medical treatment. Patients were randomized to nerve decompression or observation group (2:1). Decompression-group patients were further randomized and blinded to nerve decompression in either the right or left leg and sham surgery in the opposite leg. Pain (11-point Likert score) was compared between decompression and observation groups and between decompressed versus sham legs at 12 and 56 months. RESULTS: Of 2987 screened patients, 78 were randomized. At 12 months, compared with controls (n=37), both the right-decompression group (n=22) and left-decompression group (n=18) reported lower pain (mean difference for both: -4.46; 95% CI: -6.34 to -2.58 and -6.48 to -2.45, respectively; P < 0.0001). Decompressed and sham legs equally improved. At 56 months, compared with controls (n=m 14), pain was lower in both the right-decompression group (n=20; mean difference: -7.65; 95% CI: -9.87 to -5.44; P < 0.0001) and left-decompression group (n=16; mean difference: -7.26; 95% CI: -9.60 to -4.91; P < 0.0001). The mean pain score was lower in decompressed versus sham legs (mean difference: 1.57 95% CI: 0.46 to 2.67; P =0.0002). CONCLUSIONS: Although nerve decompression was associated with reduced pain, the benefit of surgical decompression needs further investigation as a placebo effect may be responsible for part or all of these effects.

Polyetheretherketone Implant Cranioplasty for Large Cranial Defects: A Seven-Year Follow-Up.

BACKGROUND: Goals of a cranioplasty include protection of the brain, restoration of normal appearance, and neurological function improvement. Although choice of materials for cranial remodeling has changed through the years, computer-designed polyetheretherketone (PEEK) implant has gained traction as a preferred material used for cranioplasty. However, long-term outcomes and complications of PEEK implants remain limited. The goal of this study was to report long-term clinical outcomes after PEEK implant cranioplasty. METHODS: A retrospective chart review was performed on patients undergoing PEEK cranioplasty between January 2007 and February 2023. Preoperative, intraoperative, and postoperative data were collected and analyzed. RESULTS: Twenty-two patients were included in this study. Mean postoperative follow-up time was 83.45 months (range: 35.47-173.87). Before PEEK implant cranioplasty, patients with multiple cranial procedures had undergone a mean of 2.95 procedures. PEEK implant cranioplasty indications were prior implant infection (14) and secondary reconstruction of cranial defect (8). The mean implant size was 180.43 cm2 (range: 68.00-333.06). Four patients received a 2-piece implant. Postoperative complications included: perioperative subgaleal self-resolving fluid collection in 1 patient, hematoma in another, and 3 infections resulting in explantations with successful reinsertion in 2 patients. Four of 5 patients with preoperative history of seizures reported improved seizures and all 4 patients with preoperative syndrome of the trephined reported improved symptoms and neurological function. CONCLUSION: At a mean follow-up of 7 years, most PEEK implants continued to provide protection to the brain and consistent symptom relief in patients suffering from prior postcraniectomy/craniotomy sequelae of seizures and syndrome of the trephined.

Dual-Innervated Gracilis Free Functional Muscle Transfers in Facial Palsy Patients: Comparing Long-Term Outcomes between One- versus Two-Stage Procedures.

BACKGROUND: In facial reanimation, dual-innervated gracilis free functional muscle transfers (FFMTs) may have amalgamated increases in tone, excursion, synchroneity, and potentially spontaneity when compared with single innervation. The ideal staging of dual-innervated gracilis FFMTs has not been investigated. We aim to compare objective long-term outcomes following one- and two-stage dual-innervated gracilis FFMTs. METHODS: Included were adult patients with facial paralysis who underwent either one- (one-stage group) or two-stage (two-stage group) dual-innervated gracilis FFMT with ≥1 year of postoperative follow-up. Facial measurements were obtained from standardized photographs of patients in repose, closed-mouth smile, and open-mouth smile taken preoperatively, 1 year postoperatively, and 3 years postoperatively. Symmetry was calculated from the absolute difference between the paralyzed and healthy hemiface; a lower value indicates greater symmetry. RESULTS: Of 553 facial paralysis patients, 14 were included. Five and nine patients were in the one- and two-stage groups, with mean follow-up time, respectively, being 2.5 and 2.6 years. Within-group analysis of both groups, most paralyzed-side and symmetry measurements significantly improved over time with maintained significance at 3 years postoperatively in closed and open-mouth smile (all p ≤ 0.05). However, only the two-stage group had maintained significance in improvements at 3 years postoperatively in paralyzed-side and symmetry measurements in repose with commissure position (median change [interquartile range, IQR], 7.62 [6.00-10.56] mm), commissure angle (median change [IQR], 8.92 [6.18-13.69] degrees), commissure position symmetry (median change [IQR], -5.18 [-10.48 to -1.80] mm), commissure angle symmetry (median change [IQR], -9.78 [-11.73 to -7.32] degrees), and commissure height deviation (median change [IQR], -5.70 [-7.19 to -1.64] mm; all p ≤ 0.05). In the between-group analysis, all measurements were comparable in repose, closed-mouth smile, and open-mouth smile (all p > 0.05). CONCLUSION: Long-term outcomes demonstrate that both one- and two-stage dual-innervated gracilis FFMTs significantly improve excursion, but only two-stage reconstruction significantly improves resting tone.

Lateral Tarsal Strip versus Tensor Fascia Lata Sling for Paralytic Ectropion: Comparison and Long-Term Outcomes.

BACKGROUND: Paralytic ectropion increases risk for corneal injury in facial palsy patients. Although a lateral tarsal strip (LTS) provides corneal coverage through superolateral lower eyelid pull, the unopposed lateral force may result in lateral displacement of the lower eyelid punctum and overall worsening asymmetry. A tensor fascia lata (TFL) lower eyelid sling may overcome some of these limitations. This study quantitatively compares scleral show, punctum deviation, lower marginal reflex distance, and periorbital symmetry between the two techniques. METHODS: Retrospective review was performed on facial paralysis patients who underwent LTS or TFL sling surgery with no prior lower lid suspension procedures. Standardized preoperative and postoperative images in primary gaze position were used to measure scleral show and lower punctum deviation using ImageJ, and lower marginal reflex distance using Emotrics. RESULTS: Of 449 facial paralysis patients, 79 met inclusion criteria. Fifty-seven underwent LTS surgery and 22 underwent TFL sling surgery. Compared with preoperatively, lower medial scleral show improved significantly with both LTS (10.9 mm 2 ; P < 0.01) and TFL (14.7 mm 2 ; P < 0.01). The LTS group showed significant worsening of horizontal and vertical lower punctum deviation when compared with the TFL group (both P < 0.01). The LTS group was unable to achieve periorbital symmetry between the healthy and paralytic eye across all parameters measured postoperatively ( P < 0.01); and the TFL group achieved symmetry in medial scleral show, lateral scleral show, and lower punctum deviation. CONCLUSION: In patients with paralytic ectropion, TFL sling provides similar outcomes to LTS, with the added advantages of symmetry without lateralization or caudalization of the lower medial punctum. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Dual Versus Single Innervation of Gracilis Free Functional Muscle Transfer in Facial Paralysis - Long-Term Resting and Dynamic Outcomes.

BACKGROUND: Comparing long-term tone and excursion between single- versus dual-innervated free functional muscle transfer (FFMT) in patients with longstanding facial paralysis. METHODS: Longstanding facial palsy patients treated with a FFMT innervated either by a nerve-to-masseter (single-innervation group) or by nerve-to-masseter and cross-facial-nerve graft (dual-innervation group) were included. One year minimal follow up was required. Outcome measures, based on standardized photos, included excursion, smile angle, teeth exposure, commissure height deviation, and upper lip height deviation in repose and in closed and open teeth smile preoperatively, and at 3-months, 1-year, and 3-years postoperatively. Emotrics software (Massachusetts Eye and Ear Infirmary, Boston, MA) and ImageJ (Rasband, W.S., ImageJ, U.S, National Institutes of Health, Bethesda, MD) were used for measurements. Between group and within group longitudinal comparisons were analyzed. RESULTS: At three years (single=24, dual=13), significance was found between groups in commissure position (single=26.42mm, dual=31.51mm, p<0.0001) and excursion with open mouth smile (single=31.32mm, dual=26.59mm, p<0.001). Single-innervation FFMT within group analysis lacked significant improvement in commissure height deviation and upper lip height deviation at 3 years in repose, while dual-innervation group revealed significant improvements (3.67mm and p<0.001, 3.17mm and p<0.001 respectively). Teeth exposure revealed an increase in the dual-innervation group (single=35.753 mm 2, dual=64.177 mm 2), albeit significance was not observed. CONCLUSIONS: Dually innervated FFMT revealed improvements in resting tone and teeth exposure with minimal decrease in smile excursion compared with single innervated FFMT.

Facial Nerve High-Resolution Microanatomy Analysis of the Distal Intratemporal to Extracranial Pes Segment: Reconstructive Implications.

BACKGROUND: Current knowledge of facial nerve topography between the stylomastoid foramen to the pes anserinus is very limited. Elucidating this segment's intraneural microanatomy may be advantageous in certain clinical settings: the planning of nerve grafts for gaps extending from the proximal facial nerve trunk to distal branches or in determining coaptation sites for hypoglossal jump grafts to provide selective upper and lower facial tone. This study is the first to provide high-definition intraneural topography of the aforementioned segment to optimize reconstructive outcomes. METHODS: Sixteen facial nerves extending from the second genu to the pes anserinus were harvested from eight cadavers en bloc to preserve orientation. Specimens were imaged by micro-computed tomography using a serial 6-µm protocol and digitally reconstructed three-dimensionally to be analyzed using bioinformatic tools. RESULTS: No clinically significant fascicular separation was noted between 14.4 mm proximal to the stylomastoid foramen until 4.4 mm distal to the foramen. Fascicles remained separate throughout the remainder of the specimen and were found to undergo a mean rotation of 45.5 degrees ( P = 0.0002) between 8.9 and 13.7 mm distal to the stylomastoid foramen. This reliable clockwise rotation in left nerves and counterclockwise rotation in right nerves resulted in superficially oriented fascicles entering the upper division of the pes anserinus, whereas deep-oriented fascicles entered the lower division. CONCLUSION: Intraneural facial nerve topography and rotation are consistent from 4 to 14 mm distal to the stylomastoid foramen, enabling surgeons to accurately place grafts targeted to either the upper or lower face, thus optimizing functional accuracy and minimizing synkinesis.

Selective Myectomies Alone vs Selective Myectomies Combined with Selective Neurectomies in Patients with Post-paretic Synkinesis - Comparing Outcomes.

BACKGROUND: In post-paretic synkinesis, muscle tone imbalance between upper and lower lip depressors and elevators, results in the inability to produce an effective smile. Surgical treatments to improve smile, focus on restoring tonicity balance between peri-oral muscles by weakening hyper-toned muscles through selective myectomies or selective neurectomies. The goal of this study was to compare objective outcomes between selective myectomies alone with those of selective myectomies combined with selective neurectomies. METHODS: Retrospective cohort study performed on post-paretic synkinesis patients who underwent depressor anguli oris (DAO) myectomies or DAO and platysma myectomies with selective neurectomies. Objective outcomes included pre- and post-operative analyses of smile measures (excursion, angle, and dental show) and Botox administration (periorbital and platysmal). RESULTS: Thirty-seven pa tients underwent DAO myectomies only (myectomy group) and eighteen patients underwent DAO and platysma myectomies with selective neurectomies (myectomy-neurectomy group). Within group analyses showed significant angle improvement in both groups (p<.05) and improved smile excursion in the myectomy-neurectomy group (p<.05). Between group comparisons showed significant closed mouth smile excursion improvement (difference in means: -1.14 millimeters; 95% CI -2.19 to -0.09; p=.034) and significant decrease in platysmal Botox administration (difference in means: 27.36 Botox units ; 95% CI 18.72 to 36.00; p<.001) in the myectomy-neurectomy group compared to the myectomy group. CONCLUSIONS: This study suggests that selective myectomies and selective myectomies with selective neurectomies provide overlapping and differing benefits to peri-oral synkinesis. Selective neurectomies and platysma myectomy provided slightly improved excursion and significantly decreased botulinum injections to the platysma.

Do Preoperative Depressor Anguli Oris Muscle Blocks Predict Myectomy Outcomes? A Single-Cohort Comparison in Postparetic Facial Synkinesis.

SUMMARY: The complexity of facial synkinesis will likely benefit from an individualized approach to intervene on discrete synkinetic facial subunits. This overarching treatment algorithm requires understanding each synkinetic mimetic subunit. The depressor anguli oris muscle, because of its antagonistic relationship to the zygomaticus major, is of particular interest. This study aims to provide outcomes of depressor anguli oris muscle myectomies and the predictive value of preoperative lidocaine blocks. Preoperative depressor anguli oris muscle lidocaine blocks were administered to patients with postparetic facial synkinesis, and subsequent isolated depressor anguli oris muscle myectomies were performed on those who showed improvement and elected to proceed. Twenty synkinetic patients underwent isolated depressor anguli oris myectomies after lidocaine blockade, with an average follow-up of 9 months. Facial mimetic parameters and measurements were recorded and analyzed by Massachusetts Eye and Ear Infirmary Emotrics and National Institutes of Health ImageJ software to compare results from both blocks and myectomies. Both lidocaine block and depressor anguli oris myectomy improved dental show by 14.42 mm 2 and 23.012 mm 2 , respectively, and open mouth smile angles above a horizontal plane by 4.66 and 3.32 degrees, respectively. There was no statistical difference between the groups in terms of improvements noted in closed and open mouth smile angles above a horizontal plane, or in dental show ( p = 0.695, p = 0.351, and p = 0.242, respectively). Preoperative lidocaine blockade accurately predicts the improvement in dental show and modiolus smile angle that is provided by isolated depressor anguli oris muscle myectomy. This furthers our understanding of depressor anguli oris muscle abnormality in the overall spectrum of facial synkinesis. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

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

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.