Understanding the Relationship Between Facial Nerve Branch Sacrifice and Selective Neurectomy Outcome.

Introduction: While there is great interest in selective neurectomy (SN) for patients with synkinesis, outcomes can be inconsistent. Objective: To examine the relationships between intraoperative facial nerve branch transection and both postoperative outcome and functional deficits. Methods: SN cases, with minimal follow-up of 4 months, were retrospectively identified between 2019 and 2021; outcome was assessed using FaCE instrument, eFACE and Emotrics. Correlations between intraoperative facial nerve branch preservation or transection, and functional outcome and new functional deficits were examined. Results: Fifty-six cases were performed: 88% were females, and median age was 53 years (range 11-81). Mean follow-up was 19.5 months (range 4-42). Oral commissure excursion improved in patients where all smile branches were preserved, no vertical vector smile branches were transected, and more than three smile antagonist branches were transected. A linear trend between smile antagonist branch sacrifice and favorable smile outcome was found. Lower lip movement was improved in patients in whom more than half of the identified lower lip branches were transected. Thirty percent of patients experienced untoward postoperative functional deficits, from which 47% recovered with interventions. Conclusions: Several correlations between SN intra-operative decisions and outcome were identified; new or worsening functional deficit rate can be high. However, chemodenervation or fillers can help diminish these deficits.

Favorable Outcome Perception in Facial Selective Neurectomy.

OBJECTIVE: Facial selective neurectomy (SN) improves facial function by denervation of muscles antagonistic to the smile in nonflaccid facial paralysis (NFFP) patients. This study aims to assess whether and which objective facial function metrics affect favorable SN outcome in NFFP patients, as perceived by facial nerve (FN) practitioners. STUDY DESIGN: Retrospective cohort study. SETTING: NFFP patients who underwent SN at the facial nerve center. METHODS: Standardized preoperative and postoperative facial photographs of patients undergoing SN were analyzed using clinician-graded measures (eFACE) and automated facial measurement (Emotrics). Favorable outcome was ranked subjectively by 3 independent FN practitioners. Correlations between objective metrics and favorable subjective outcome were examined. RESULTS: Fifty-eight SN cases were included. Oral commissure excursion with smile, interlabial distance, and lower lip movement were all considered statistically significantly important for favorable outcome perception. Each +1 mm of smile excursion increases the odds of a favorable outcome by 75.4% (odds ratio [OR]: 1.754). Each +1 mm of interlabial distance asymmetry decreases the odds of a favorable outcome by 24.7% (OR: 0.753). Each +1-point change in lower lip movement eFACE score increases the odds of a favorable outcome by 2.7% (OR: 1.027). CONCLUSION: Several smile metrics contribute to favorable SN outcome perception among FN practitioners. Smile excursion, interlabial distance, and lower lip movement were significant predictors of success. These observations may be extrapolated to other facial reanimation interventions and serve surgeons and patients during counseling and expectation management, and during surgery.

Pre-Operative Factors May Predict Outcome in Selective Neurectomy for Synkinesis.

Background: While there has been great interest in offering selective neurectomy (SN) to patients with nonflaccid facial palsy (NFFP), postoperative outcomes are inconsistent. Objective: To assess overall SN outcome in NFFP patients and to examine correlation between preoperative factors and SN outcome. Methods: SN cases were retrospectively identified between 2019 and 2021. Patient factors and facial function were assessed using chart review, the Facial Clinimetric Evaluation (FaCE), the electronic clinician-graded facial function tool (eFACE), and an automated computer-aided facial assessment tool (Emotrics). Correlations between preoperative factors and patients outcome were established. Results: Fifty-eight SN cases were performed; 88% were females, and median age was 53 years (range 11-81). Outcome assessment was 8 months on average (1-24 months). Postoperatively, multiple eFACE and Emotrics parameters improved significantly, including ocular, perioral, and synkinesis metrics. In preoperative factors assessment, age >50, facial palsy (FP) duration >2 years, poor preoperative facial function, and nontrauma etiology all correlated with greater improvements compared with younger patients, those with shorter duration facial palsy, trauma etiology, and better preoperative facial function. Conclusions: SN can significantly improve facial function; we have identified several preoperative factors that correlated to outcome.

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

OBJECTIVE: 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. STUDY DESIGN: To understand the structure/function relationships of the distal lower facial nerve branches and lower lip musculature. SETTING: In vivo extensive facial nerve dissections under general anesthesia. METHODS: Intraoperative mapping was performed in 60 cases, using branch stimulation and simultaneous movement videography. RESULTS: 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. CONCLUSION: 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.

Machine Learning Generated Synthetic Faces for Use in Facial Aesthetic Research.

Importance: A centralized repository of clinically applicable facial images with unrestricted use would facilitate facial aesthetic research. Objective: Using a machine learning neural network, we aim to (1) create a repository of synthetic faces that can be used for facial aesthetic research and (2) analyze synthetic faces according to contemporary aesthetic principles. Design, Setting, and Participants: Synthetic facial images were generated using an open source generative adversarial network. Images were refined and then analyzed using computer vision technology. Interventions: Not applicable. Main Outcomes and Measures: Synthetic facial images were created for use as a facial aesthetic research data set. Results: One thousand synthetic images were generated, and 60 images underwent analysis. Image attributes, including age, gender, image principle axis, facial emotion, and facial landmark points, were attained. Images demonstrated accordance with contemporary aesthetic principles of horizontal thirds and vertical fifths. Images demonstrated excellent correspondence when compared with real human facial photographs. Conclusions and Relevance: We have generated realistic synthetic facial images that have potential as a valuable research tool and demonstrate similarity to real human photographs while adhering to contemporary aesthetic principles.

Appraising Otolaryngology-Head and Neck Surgery Clinical Practice Guidelines for Effective Dissemination and Implementation Design.

OBJECTIVES: Dissemination and implementation (D&I) science analyzes interventional strategies that aid in spreading scientific knowledge, adopting evidence into practice, and identifying barriers to maximize successful integration of science into practice. This study set out to critically appraise the published D&I strategies of the American Academy of Otolaryngology-Head and Neck Surgery Foundation (AAO-HNSF) Clinical Practice Guidelines (CPGs) and to introduce the theories of D&I science. METHODS: The 15 AAO-HNSF CPGs underwent appraisal by 2 independent reviewers using the Appraisal of Guidelines for Research & Evaluation II (AGREE II) instrument. CPGs were rated over 23 key items in 6 domains. Each item was rated on a 7-point scale from 1 (strongly disagree) to 7 (strongly agree). CPGs were rated and quality assessments were performed. Intrarater reliability was assessed. RESULTS: The overall mean score of the CPGs was 85.2% (95% confidence interval, 83.4%-86.9%). Individual CPG mean scores ranged from 80.4% to 90.9%. Mean interrater reliability was strong. All domains of the AGREE II instrument, except the Applicability domain, scored a mean of 90.7% or better. D&I strategies within the CPGs, as calculated by the Applicability domain score, ranged from 22.9% to 77.1%. DISCUSSION: There is a paucity of published D&I strategies within the AAO-HNSF CPGs. Nesting a D&I framework, such as the Quality Improvement Framework, within CPGs would allow for identification of barriers to CPG adoption and evaluation of CPG-directed interventions. IMPLICATIONS FOR PRACTICE: A D&I framework within the AAO-HNSF CPGs would allow for objective measurement of the overall impact of CPGs on otolaryngology practices.

Twenty-year perspective of randomized controlled trials for surgery of chronic nonspecific low back pain: citation bias and tangential knowledge.

BACKGROUND CONTEXT: After decades of clinical research, the role of surgery for chronic nonspecific low back pain (CNLBP) remains equivocal. Despite significant intellectual, human, and economic investments into randomized controlled trials (RCTs) in the past two decades, the role of surgery in the treatment for CNLBP has not been clarified. PURPOSE: To delineate the historical research agenda of surgical RCTs for CNLBP performed between 1993 and 2012 investigating whether conclusions from earlier published trials influenced the choice of research questions of subsequent RCTs on elucidating the role of surgery in the management of CNLBP. STUDY DESIGN: Literature review. METHODS: We searched the literature for all RCTs involving surgery for CNLBP. We reviewed relevant studies to identify the study question, comparator arms, and sample size. Randomized controlled trials were classified as "indication" trials if they evaluated the effectiveness of surgical therapy versus nonoperative care or as "technical" if they compared different surgical techniques, adjuncts, or procedures. We used citation analysis to determine the impact of trials on subsequent research in the field. RESULTS: Altogether 33 technical RCTs (3,790 patients) and 6 indication RCTs (981 patients) have been performed. Since 2007, despite the unclear benefits of surgery reported by the first four indication trials published in 2001 to 2006, technical trials have continued to predominate (16 vs. 2). Of the technical trials, types of instrumentation (13 trials, 1,332 patients), bone graft materials and substitutes (11 trials, 833 patients), and disc arthroplasty versus fusion (5 trials, 1,337 patients) were the most common comparisons made. Surgeon authors have predominantly cited one of the indication trials that reported more favorable results for surgery, despite a lack of superior methodology or sample size. Trials evaluating bone morphogenic protein, instrumentation, and disc arthroplasty were all cited more frequently than the largest trial of surgical versus nonsurgical therapy. CONCLUSIONS: The research agenda of RCTs for surgery of CNLBP has not changed substantially in the last 20 years. Technical trials evaluating nuances of surgical techniques significantly predominate. Despite the publication of four RCTs reporting equivocal benefits of surgery for CNLBP between 2001 and 2006, there was no change in the research agenda of subsequent RCTs, and technical trials continued to outnumber indication trials. Rather than clarifying what, if any, indications for surgery exist, investigators in the field continue to analyze variations in surgical technique, which will probably have relatively little impact on patient outcomes. As a result, clinicians unfortunately have little evidence to advise patients regarding surgical intervention for CNLBP.

Patterns of strain and activation in the thigh muscles of goats across gaits during level locomotion.

Unlike homologous muscles in many vertebrates, which appear to function similarly during a particular mode of locomotion (e.g. red muscle in swimming fish, pectoralis muscle in flying birds, limb extensors in jumping and swimming frogs), a major knee extensor in mammalian quadrupeds, the vastus lateralis, appears to operate differently in different species studied to date. In rats, the vastus undergoes more stretching early in stance than shortening in later stance. In dogs, the reverse is true; more substantial shortening follows small amounts of initial stretching. And in horses, while the vastus strain trajectory is complex, it is characterized mainly by shortening during stance. In this study, we use sonomicrometry and electromyography to study the vastus lateralis and biceps femoris of goats, with three goals in mind: (1) to see how these muscles work in comparison to homologous muscles studied previously in other taxa; (2) to address how speed and gait impact muscle actions and (3) to test whether fascicles in different parts of the same muscle undergo similar length changes. Results indicate that the biceps femoris undergoes substantial shortening through much of stance, with higher strains in walking and trotting [32-33% resting length (L0)] than galloping (22% L0). These length changes occur with increasing biceps EMG intensities as animals increase speed from walking to galloping. The vastus undergoes a stretch-shorten cycle during stance. Stretching strains are higher during galloping (15% L0) than walking and trotting (9% L0). Shortening strains follow a reverse pattern and are greatest in walking (24% L0), intermediate in trotting (20% L0) and lowest during galloping (17% L0). As a result, the ratio of stretching to shortening increases from below 0.5 in walking and trotting to near 1.0 during galloping. This increasing ratio suggests that the vastus does relatively more positive work than energy absorption at the slower speeds compared with galloping, although an understanding of the timing and magnitude of force production is required to confirm this. Length-change regimes in proximal, middle and distal sites of the vastus are generally comparable, suggesting strain homogeneity through the muscle. When strain rates are compared across taxa, vastus shortening velocities exhibit the scaling pattern predicted by theoretical and empirical work: fascicles shorten relatively faster in smaller animals than larger animals (strain rates near 2 L s-1 have been reported for trotting dogs and were found here for goats, versus 0.6-0.8 L s-1 reported in horses). Interestingly, biceps shortening strain rates are very similar in both goats and rats during walking (1-1.5 L s-1) and trotting (1.5-2.5 L s-1, depending on speed of trot), suggesting that the ratio of in vivo shortening velocities (V) to maximum shortening velocities (Vmax) is smaller in small animals (because of their higher V(max)).