Relational Anatomy of the Mimetic Muscles and Its Implications on Free Functional Muscle Inset in Facial Reanimation.

BACKGROUND: The human smile is a complex coordinated activity of mimetic muscles predominantly recognizable by a superolateral pull at the commissure and elevation of the upper lip. The aim of this study was to revisit the muscles of facial expression responsible for these motions, evaluate their relational anatomy and orientation, and relate this to optimal positioning of free muscle transfer in smile reanimation. METHODS: Nineteen hemifaces from fresh cadaveric specimens were dissected. A subsuperficial muscular aponeurotic system skin flap was elevated to expose the zygomaticus major, zygomaticus minor, levator labii superioris, and levator labii superioris alaeque nasi. Muscle location, length, width, angle of pull, and any anatomic variation were noted. RESULTS: All specimens had zygomaticus major, levator labii superioris, and levator labii superioris alaeque nasi muscles present bilaterally. Conversely, the zygomaticus minor was present in only 10 of 19 hemifaces. There was no significant difference in muscle length, width, or line of pull between specimen sides. Of all the assessed muscles, the zygomaticus minor had the most transverse line of pull, at 31.6°; the zygomaticus major was more oblique with a line of pull of 55.5°; and the levator labii superioris and levator labii superioris alaeque nasi were oriented almost vertically with angles of 74.7° and 79.0°, respectively. CONCLUSIONS: The mimetic muscle vector is quite vertical in comparison to the angle obtained by traditional dynamic smile reconstruction surgeries. A more vertical vector, especially at the upper lip, should be considered in smile reconstruction.

Management of the Inferior Alveolar Nerve in Large Sagittal Split Advancements: To Free or Not?

SUMMARY: The purpose of this study was to evaluate whether neurosensory recovery of the inferior alveolar nerve (IAN) is influenced by its location following sagittal split osteotomy (SSO) in patients undergoing large mandibular movements. This was a prospective, split-mouth study of skeletally mature patients undergoing bilateral SSO. Patients were included as study subjects if they underwent bilateral SSO for mandibular advancement greater than 10 mm and, following the splits, the IAN was freely entering the distal segment on one side and within the proximal segment on the other. Descriptive, bivariate, and Kaplan-Meier statistics were computed. The study sample included 13 subjects (eight female subjects; mean age, 18.7 ± 1.8 years) undergoing 26 SSOs. Eleven subjects underwent bimaxillary surgery; 10 had simultaneous genioplasty. The mean mandibular movement was 12.2 ± 1.4 mm and was not significantly different between sides ( P = 0.43). All subjects achieved functional sensory recovery (FSR) bilaterally within 1 year of surgery. There was no difference in the median times to FSR based on the location of the IAN (distal segment, 105 days, versus proximal segment, 126 days; P = 0.57). In SSO for mandibular advancement with movements greater than 10 mm, leaving the IAN within the proximal segment may not impact time to FSR. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, II.

DOES THE LOW AND SHORT MEDIAL CUT AFFECT LINGUAL NERVE RECOVERY AFTER SAGITTAL SPLIT OSTEOTOMY?

PURPOSE: To evaluate the recovery of lingual nerve (LN) neurosensory function in patients undergoing sagittal split osteotomy (SSO) with a low and short medial horizontal cut. MATERIALS AND METHODS: This was a prospective study of patients with mandibular deformities undergoing SSO with a low and short medial horizontal cut over a 4-year period. The outcomes of interest were neurosensory recovery of the LN, as assessed objectively using functional sensory recovery (FSR) and subjectively by patient report. RESULTS: The sample included 123 SSOs in 62 subjects with a mean age of 19.3 ± 3.1 years. Thirty-seven (61.7%) subjects were female. Mandibular advancements were performed in 52 SSOs (42.3%); mandibular setbacks were performed in 71 SSOs (57.7%). One subject underwent revision BSSO. FSR was achieved at 122 LNs (99.1%) within 6-weeks post-operatively, with 120 sites (97.5%) having S4 sensation at 6-weeks. Decreased LN sensation was reported at 10 (8.3%) sites at 1-week post-operatively. At 6-weeks post-operatively, 118 sites (97.5%) had reported normal sensation. By 12-weeks post-operatively, all LN sites had S4 sensation and there were no subjective complaints. Revision sagittal split osteotomy was associated with prolonged (≥6 weeks) time to S4 sensation (p = 0.02) and subjective complaint of decreased sensation (p = 0.02). CONCLUSION: LN sensory recovery occurs rapidly following the low and short SSO, with 99% of sites achieving FSR and subjectively normal sensation within 6-weeks of surgery and all patients achieving FSR with S4 sensation by 12-weeks post-operatively. LN sensory recovery may be prolonged in patients undergoing revision SSO.

Pediatric Nasal and Septal Fractures.

Pediatric nasal bone and septal fractures represent a large number of craniofacial injuries in children each year. Due to their differences in anatomy and potential for growth and development, the management of these injuries varies slightly from that of the adult population. As with most pediatric fractures, there is a bias toward less-invasive management to limit disruption to future growth. Often this includes closed reduction and splinting in the acute setting followed by open septorhinoplasty at skeletal maturity as needed. The overall goal of treatment is to restore the nose to its preinjury shape, structure, and function.

Fronto-Orbital Advancement for Metopic and Unilateral Coronal Craniosynostoses.

Fronto-orbital advancement remains a powerful technique for the correction of anterior cranial vault differences related to metopic (trigonocephaly) or unilateral coronal (anterior plagiocephaly) craniosynostoses. Traditional fronto-orbital advancement requires access to the forehead and superior 2/3 of the orbit via a coronal incision. The frontal bone and orbital segment (bandeau) are then separated from the skull and reshaped. In patients with metopic craniosynostosis, the bandeau and frontal bone will need to be advanced and widened. In patients with unilateral coronal craniosynostosis, the bandeau will need to be "untwisted" to address the supraorbital retrusion on the affected side, the affected orbit will need to be shortened and widened, and the frontal bone flap will need to be proportionately advanced on the affected side. Overcorrection of the affected dimension should be undertaken to account for growth and relapse.

Management of Artery-Only Digit Replantation: A Systematic Review of the Literature.

BACKGROUND: Artery-only replantation may be necessary in circumstances when venous repair cannot be performed due to their size or vessel injury. Venous congestion of the replanted part is inevitable. A systematic review was performed to identify techniques for mitigating congestion and analyze the outcomes of those techniques. METHODS: A comprehensive literature search was performed to identify relevant articles related to artery-only replantation. An initial query identified 1286 unique articles. A total of 55 articles were included in the final review. Included studies were categorized by decongestive technique. Data from each article included the number of patients treated, level of amputation, graft use, anticoagulation or antiplatelet therapy, replant viability, and follow-up duration. Weighted averages were determined from studies that reported five or more digits. RESULTS: A total of 1498 individual digital replantations were described. Very rarely did studies report artery-only replantation proximal to the distal interphalangeal joint. An overall survival rate of 78.5 percent was found irrespective of technique but was variable based on each particular study. Studies utilizing medicinal leech therapy were more likely to report use of intravenous anticoagulation, whereas surface bleeding techniques were more likely to report use of topical or local anticoagulant. CONCLUSIONS: Lack of a vein for anastomosis should not be regarded as a contraindication to replantation. These digits instead require a method to establish reliable drainage sufficient to allow for low resistance inflow and maintain a physiologic pressure gradient across capillary beds. The surgeon should select a decongestive technique that best suits the patient and their specific injury.

Burn Outcomes at Extremes of Body Mass Index: Underweight Is as Problematic as Morbid Obesity.

Limited evidence suggests that obesity adversely affects burn outcomes. However, the impacts of body mass index (BMI) across the continuum have not been fully characterized. Therefore, we aimed to characterize outcomes after burn injury across the BMI continuum. We hypothesized that "normal" BMI (18.5-24.9) would have the lowest mortality and complication rates. The US National Trauma Data Bank (NTDB) was queried for adult burn-injured patients from 2007 to 2015. Admission BMI was calculated and grouped according to World Health Organization (WHO) classification. The primary outcome was in-hospital mortality. Secondary outcomes of time to wound closure, length of stay, and inpatient complications were similarly assessed. Of the 116,008 burn patient encounters that were identified, 7243 underwent at least one operation for wound closure. Mortality was lowest in the overweight (P = .039) and obese I cohorts (BMI 25-29.9, 30.0-34.9) at 2.9% and increased in both directions of the BMI continuum to 4.1% in the underweight (P = .032) and 5.1% in the morbidly obese (class III) group (P = .042). Time to final wound closure was longest in the two BMI extremes. BMI ≥40 was associated with increased intensive care unit days, ventilator days, renal and cardiac complications. BMI <18.5 had increased hospital days and rates of sepsis. Aberrations in metabolism associated with both increases and decreases of body weight may cause pathophysiologic changes that lead to worsened outcomes in burn-injured patients. In addition to morbidly obese patients, underweight patients also experience increased burn-related death and complications. In contrast, overweight BMI patients may have greater physiologic reserves without the burden of obesity or sarcopenia.

National Evaluation of the Association Between Resident Labor Union Participation and Surgical Resident Well-being.

Importance: Labor unions are purported to improve working conditions; however, little evidence exists regarding the effect of resident physician unions. Objective: To evaluate the association of resident unions with well-being, educational environment, salary, and benefits among surgical residents in the US. Design, Setting, and Participants: This national cross-sectional survey study was based on a survey administered in January 2019 after the American Board of Surgery In-Training Examination (ABSITE). Clinically active residents at all nonmilitary US general surgery residency programs accredited by the American Council of Graduate Medical Education who completed the 2019 ABSITE were eligible for participation. Data were analyzed from December 5, 2020, to March 16, 2021. Exposures: Presence of a general surgery resident labor union. Rates of labor union coverage among non-health care employees within a region were used as an instrumental variable (IV) for the presence of a labor union at a residency program. Main Outcomes and Measures: The primary outcome was burnout, which was assessed using a modified version of the abbreviated Maslach Burnout Inventory and was defined as experiencing any symptom of depersonalization or emotional exhaustion at least weekly. Secondary outcomes included suicidality, measures of job satisfaction, duty hour violations, mistreatment, educational environment, salary, and benefits. Results: A total of 5701 residents at 285 programs completed the pertinent survey questions (response rate, 85.6%), of whom 3219 (56.5%) were male, 3779 (66.3%) were White individuals, 449 (7.9%) were of Hispanic ethnicity, 4239 (74.4%) were married or in a relationship, and 1304 (22.9%) had or were expecting children. Among respondents, 690 residents were from 30 unionized programs (10.5% of programs). There was no difference in burnout for residents at unionized vs nonunionized programs (297 [43.0%] vs 2175 [43.4%]; odds ratio [OR], 0.92 [95% CI, 0.75-1.13]; IV difference in probability, 0.15 [95% CI, -0.11 to 0.42]). There were no significant differences in suicidality, job satisfaction, duty hour violations, mistreatment, educational environment, salary, or benefits except that unionized programs more frequently offered 4 weeks instead of 2 to 3 weeks of vacation (27 [93.1%] vs 52 [30.6%]; OR, 19.18 [95% CI, 3.92-93.81]; IV difference in probability, 0.77 [95% CI, 0.09-1.45]) and more frequently offered housing stipends (10 [38.5%] vs 9 [16.1%]; OR, 2.15 [95% CI, 0.58-7.95]; IV difference in probability, 0.62 [95% CI 0.04-1.20]). Conclusions and Relevance: In this evaluation of surgical residency programs in the US, unionized programs offered improved vacation and housing stipend benefits, but resident unions were not associated with improved burnout, suicidality, job satisfaction, duty hour violations, mistreatment, educational environment, or salary.

Early Masseter to Facial Nerve Transfer May Improve Smile Excursion in Facial Paralysis.

BACKGROUND: Masseter-to-facial nerve transfer has been shown to be an effective and safe treatment option in patients with acute and subacute facial palsy. The present article aims to characterize whether there is a benefit in early nerve transfers while minimizing other confounding variables; we present a study that consist of only patients with complete facial nerve paralysis resulting from intratemporal facial nerve resections. METHODS: Between 2012 and 2016, 7 masseter-to-facial nerve transfers were performed for complete facial nerve palsy after intratemporal proximal nerve resections. Pre- and postoperative photographic and video evaluations were performed using both the Sunnybrook facial grading scale and the MEEI FACE-gram software for more objective metric measurements. Statistical analysis was performed to determine which patient and surgical variables had significant effects on outcome. RESULTS: Mean 14-month follow-up revealed that patients who underwent nerve transfer prior to 6 months' denervation achieved postoperative oral commissural excursion of 11.1 mm versus 6.5 mm in patients who underwent nerve transfer after 6 months (P = 0.003). Performing masseter-to-facial nerve transfer to the main facial nerve trunk resulted in a significantly higher improvement in the modiolus-philtral ratio (31.6% versus 6.1%) than selective transfer in patients (P = 0.01) at the latest follow-up. CONCLUSIONS: Early masseter-to-facial nerve transfers, before 6 months of palsy duration, can potentially improve smile excursion and symmetry of open mouth smile. Additionally, truncal coaptations may provide improved tone over coapting to selective facial nerve branches. These findings necessitate larger studies regarding the importance of denervation time with fifth-to-seventh nerve transfers.

Correlation between Facial Nerve Axonal Load and Age and Its Relevance to Facial Reanimation.

BACKGROUND: Two-stage facial reanimation procedures with a cross-facial nerve graft often have unsatisfactory results in the older patient. Although the cause of result variability is likely multifactorial, some studies suggest that increased donor nerve axonal load improves function of a free muscle transfer after a cross-facial nerve graft. This study attempts to characterize the relationship between age and facial nerve axonal load. METHODS: Sixty-three fresh cadaveric heads were dissected to expose the facial nerve. For each hemiface, two facial nerve samples were taken: one proximal as the nerve exits the stylomastoid foramen, and one distal at the buccal branch (at a point 1 cm proximal to the anterior parotid border). Nerve samples were stained and quantified. Correlation analysis was completed using a Pearson correlation coefficient. RESULTS: Thirty-six female and 27 male cadavers were dissected; their average age was 71 years (range, 22 to 97 years). At the proximal (r = -0.26; p < 0.01; n = 104) and distal (r = -0.45; p < 0.0001; n = 114) sampling points, there was a significant negative correlation between age and axonal load. CONCLUSIONS: As age increases, the axonal load of the facial nerve decreases at the buccal and zygomatic branches approximately 1 cm proximal to the anterior parotid border. The authors previously suggested this location as significant for cross-facial nerve coaptation. These results propose that decreasing axonal load can be a factor in the unsatisfactory outcomes of cross-facial grafting in the aging population. Moreover, this underscores the importance of recruiting more donor axons in attempting to improve facial reanimation in the older patient.