Scientific Abstract Presentations: Craniomaxillofacial Session 8 Saturday, October 11 Sat, Oct 11 10:30 a.m.-12:30 p.m. CDT

Background: Mandibular distraction osteogenesis (MDO) is an effective treatment for life-threatening upper airway obstruction in pediatric patients with micrognathia. However, recent data on how age at the time of distraction affects complication rates is limited. This study seeks to fill this gap by evaluating age-related risks associated with MDO and offering updated insights into complication rates based on patient age at the time of surgery.

Methods: A retrospective review on patients who underwent MDO between 2004 and 2023 at a tertiary institution was conducted. Patients with less than 6 months of follow-up were excluded from the analysis. The study population was divided into three equal groups by age at surgery: less than 3 weeks old, 3–14 weeks old, and greater than 14 weeks old at time of MDO. Primary outcomes assessed were 30-day postoperative infection rates, major complications (defined as those requiring rehospitalization or reoperation), and minor complications (defined as self-resolving or medically managed issues that did not require hospitalization or general anesthesia). Statistical analyses were performed using Fisher's exact test, Pearson's chi-squared test, and the Mann-Whitney U test.

Results: A total of 133 patients met the inclusion criteria, with a median age of 5.6 weeks at the time of surgery and a median follow-up of 6.1 years. Preoperative tracheostomy was only observed in the oldest cohort (9.3%, p=0.16). There were no significant differences across cohorts in the presence of craniofacial syndromes, total distraction distance, distraction rate, or activation duration. Postoperative outcomes revealed no significant differences in major complications or 30-day infection rates. However, minor complication rates were highest in the youngest cohort at 53.5%, followed by 39.5% in the 3–14 weeks cohort, and 20.9% in the oldest cohort (p=0.008). Specifically, wound dehiscence that did not require surgical intervention was most prevalent in the youngest cohort (20.9%), this was significantly higher than the 2.3% rate in the 3–14 weeks cohort and the 4.7% in the oldest cohort (p=0.005). No significant differences were observed in need for postoperative tracheostomy or oxygen requirements across cohorts.

Conclusion: Age does not significantly affect major complications following MDO, however, younger patients may be at a higher risk for minor complications, such as wound dehiscence. Overall, MDO remains a safe and effective procedure for patients of all ages, though attention to wound care and nutrition is especially critical for those who undergo surgery before three weeks of age.

Background Recent studies have identified various socioeconomic disparities in postoperative outcomes among adults undergoing head and neck (H&N) microsurgical reconstruction (1, 2). This dynamic has yet to be rigorously evaluated within the pediatric context. This study aimed to measure the impact of socioeconomic factors on outcomes of H&N free tissue transfer in a pediatric population.

Methods A retrospective review was conducted of children who underwent H&N free tissue transfer (FTT) at a tertiary children's hospital from May 2007 to May 2024. Patients were grouped into cohorts according to the Area Deprivation Index (ADI) associated with their household zip code. ADI is a composite measure designed to quantify the geographic distribution of socioeconomic deprivation on a 10-point scale. Cohorts were defined as low deprivation for ADI 1-5 and high deprivation for ADI 6-10. Patients were further characterized by race, insurance status, and primary diagnosis. Outcomes included flap failure, flap dehiscence, flap revision, and duration of hospitalization.

Results A total of 59 patients, undergoing 75 FTTs, met inclusion criteria, among whom 43.1% were considered low deprivation and 56.9% high deprivation. Mean age at surgery was 11.8 ± 4.8 years. Overall flap survival was 97.3%. Rates of flap failure, unanticipated revision, and readmission did not differ between cohorts. However, flap dehiscence was significantly more likely among high deprivation patients (25.6% vs. 6.2%, p=0.034). Furthermore, every 1 point increase in ADI over 5 was associated with a 7.8% increase in the odds of flap dehiscence (p<0.05).

Discussion Neighborhood socioeconomic deprivation was independently predictive of flap dehiscence among children undergoing H&N FTT, but was not associated with flap failure, flap revisions, or 30-day readmissions. This finding underscores the broader impact of socioeconomic factors on pediatric health outcomes, particularly surgical wound healing. Poor nutrition, lower health literacy, and limited resources may drive this dynamic within our study population. Integrating socioeconomic considerations into pediatric microsurgical care may optimize outcomes for vulnerable patients after head and neck free flap reconstruction.

References

1. Njoroge MW, Karwoski AS, Gornitsky J, et al. Socioeconomic Disparities in Postoperative Outcomes of Osteocutaneous Fibula Free Flaps for Head and Neck Reconstruction. Ann Plast Surg. 2024;92(4S Suppl 2):S167-S171. doi:10.1097/SAP.0000000000003869

2. Goldberg ZN, Jain A, Wu R, Cognetti DM, Goldman RA. Social Determinants of Health Impact Complications Following Free-Flap Reconstruction for Head and Neck Cancer.

Introduction: Since its introduction by Hidalgo in 1989, the free fibula flap has been the gold standard for mandibular reconstruction following oncologic resections. Despite advancements such as fibula-cutting guides, implant exposure remains a major complication, leading to increased patient morbidity and healthcare costs. Plate exposure rates in the literature range from 10% to 15%, with surgical site infections identified as a significant risk factor. While negative pressure dressings and local flap coverage may mitigate exposure, severe cases often necessitate implant removal and secondary reconstruction. This study presents a novel osteotomy technique designed to improve implant coverage, reduce long-term exposure, and enhance outcomes, particularly in the setting of postoperative radiotherapy. Materials and Methods: A retrospective review of 580 free fibula flaps performed for mandibular reconstruction between January 2018 and December 2024 was conducted. Patients undergoing primary unilateral mandibular reconstruction were included, while those receiving double free flaps, secondary reconstructions, or treatment for recurrence were excluded. Patients were categorized into two groups: Group A (implant exposure) and Group B (no implant exposure). Demographic variables, comorbidities, pre- and postoperative radiotherapy, ischemia time, soft tissue coverage, flap complications, and reconstructive outcomes were analyzed. Statistical analysis included univariate and multivariate logistic regression to identify independent risk factors for implant exposure. Results: Implant exposure occurred in 9 out of 580 cases (1.55%). Group A patients were significantly older (mean age: 58.11 years vs. 51.81 years, p = 0.027) and more likely to have undergone central segment reconstruction (p = 0.004). Adequate muscle coverage over the implant was significantly lower in Group A (33.33%) compared to Group B (97.02%, p < 0.0001), highlighting the importance of soft tissue protection. Postoperative chemoradiotherapy (CTRT) was significantly lower in Group A (33.33%) compared to Group B (76.53%, p = 0.008), suggesting a protective effect of adjuvant therapy. Total flap ischemia time was also lower in Group A (35 minutes vs. 41 minutes, p < 0.0001). Multivariate analysis identified age ≥65 years (OR = 7.263, p = 0.023), central segment reconstruction (OR = 43.357, p = 0.001), and inadequate muscle cover (OR = 22.669, p < 0.0001) as independent risk factors for implant exposure. Discussion: Insufficient soft tissue coverage is a primary contributor to implant exposure and osteoradionecrosis (ORN). Our technique incorporates the flexor hallucis longus (FHL) muscle for additional coverage, significantly reducing implant exposure. Central segment reconstructions demonstrated the highest exposure risk, likely due to difficulty in achieving adequate muscle coverage in this region. Modifications such as harvesting a longer FHL muscle or discarding the distal 2–3 cm of fibula may enhance implant protection. While smoking and preoperative radiation are known risk factors for poor wound healing, they were not significantly associated with exposure in our study.

Background: Trauma is a major cause of injury and mortality in children, and facial fractures in pediatric patients can lead to significant aesthetic, functional, and psychosocial issues. However, mechanisms and management of pediatric midface fractures, especially maxillary fractures, have not been extensively studied. This study analyzes injury mechanisms and treatment approaches for maxillary fractures in children and adolescents over two decades.

Methods: A retrospective review was conducted on patients with maxillary fractures treated at a major children's hospital from 2005 to 2024. Inclusion criteria focused on patients with Le Fort, dentoalveolar, or maxillary wall fractures confirmed by CT. Data collected included age, gender, fracture mechanism, type, referral, dental complications, and treatment. Patients were categorized into two age groups: children (0-12 years) and adolescents (13-18 years).

Results: Of 2401 patients with maxillofacial fractures, 176 had maxillary fractures. The mean age was 7.5 ± 3.5 years in children (89 patients) and 15.9 ± 2.5 years in adolescents (87 patients), with a male-to-female ratio of 2.75:1. Falls were the most common cause, followed by baseball injuries. Adolescents were 9 times more likely to sustain fractures from assault than children (18.4% vs. 2.7%, p<0.05). Most fractures were managed conservatively, while 24% required open reduction and fixation. Management methods, dentoalveolar fractures, tooth injuries, and referral types did not vary significantly between the age groups.

Conclusions: Falls were the primary cause of maxillary fractures across both age groups, with a higher male incidence. Adolescents were more likely to suffer fractures from assault compared to younger children. While conservative treatment prevailed, open reduction and fixation were effective for severe cases. These findings underscore the need for tailored strategies to prevent and manage midface fractures in pediatric patients, especially in adolescents affected by interpersonal violence.

Background Free tissue transfer has become the standard procedure for head and neck reconstruction after cancer ablation. Thigh fap is the mainstream region for flap harvest and anterolateral thigh (ALT) flap is also the most common workhorse flap. However, some reasons that ALT flap could not be used such as it has been used before in recurrent case, or could not see visible sizable perforators intraoperatively. In this retrospective study, the authors present an alternative method using the posteromedial thigh (PMT) perforator flap for head and neck reconstruction and its clinical indications and complications encountered.
Materials and Methods This is a retrospective study, reviewing 1026 patients' electronic records who had undergone head and neck reconstruction in Kaohsiung Medical University Hospital from 2016 to 2022.
Posteromedial thigh (PMT) perforator flap which major originated from profunda femoral artery was used in 52 patients for head and neck reconstruction, average age of 61.4 years old (ranged from 45 to 81). Fifty-one of the patients were men. 27 of them were undergoing their third operation, while 9 were receiving their fourth operation. Locations of the defects after cancer resection included buccal area (n=11), tongue (n=6), mandible (n=5), lower gingiva (n=4), upper gingiva (n=2), hard palate (n=5), hypopharynx (n=1), lower lip (n = 4), oropharynx (n=2), cheek (n=1), retromolar trigone (n=1), floor of mouth (n=1), soft palate and right tongue base (n=1), left mandible and lower lip (n=1), floor of mouth and right mandible (n=1), buccal and left lower gingiva (n=1). Results Previous operations include: bilateral anterolateral thigh flap (ALT) (n=25), bilateral ALT and unilateral PMT or fibular flap (n=9), left ALT and left tensor fascia latae (TFL) or PMT flap (n=12), and no previous surgery but unusable ALT flap during flap dissection or surgeon's preference (n=6). Forty-seven reconstruction cases were secondary to head and neck cancer resection, 3 for osteoradionecrosis and 2 cases for releasing of fibrosis. In this series, the pedicle length of PMT flap was around 8-12 cm. Most perforators were located 8 to 12 cm away from the pubic crease on the reference line between the perineum and the insertion of the semitendinosus muscle. The average of perforator number was around 2 (range, 1 to 3). Most were musculocutaneous perforators. Flap size around 15x6 cm to 25x8cm. There was a 30% complication rate (n=16) including 6 infections, 6 vascular compromise, 1 hematoma, 3 mixture of hematoma, infection and vascular compromise. The overall success rate was 88.5%. Six flaps (11.5%) failed which the flaps were unsalvageable and subsequently reconstruction with contralateral PMT (n=4) and ALT (n=2) were successfully used. Conclusion PMT flap is a good option for head and neck reconstruction for difficult cases whereby patients had already undergone two to three unsuccessful reconstruction. PMT can be considered even when ALT flap has already been harvested on the same leg. The location of the perforators is consistent, and the pedicle length is suitable for this reconstruction. The donor-site scar is well concealed and has minimal and comparable morbidity to other thigh flaps.

Introduction: Craniofacial deformities, including craniosynostosis, midface underdevelopment, and orbital asymmetries, can result in both aesthetic and functional complications such as proptosis and distorted orbital geometry. Surgical techniques such as subcranial Lefort III osteotomy, fronto-orbital advancement (FOA), and periorbital osteotomies are designed to address these abnormalities by reshaping skeletal structures. However, their secondary effects on orbital volume augmentation are not well-documented. Methodology: This study analyzed orbital volume changes in eight following craniofacial surgeries. Orbital volumes were assessed pre- and postoperatively using DICOM-based CT imaging processed with InVivo Anatomage software. Results were compared with age- and sex-specific normative data to determine both absolute and normalized volume changes. Surgical procedures included one subcranial Lefort III osteotomy, three FOA cases, and four periorbital osteotomies. Results: All procedures demonstrated improvements in orbital volume, with subcranial Lefort III osteotomy producing the most significant increases. FOA primarily enhanced the superior orbital region, yielding moderate volume restoration. Periorbital osteotomies, including box and segmental osteotomies, provided localized adjustments to correct asymmetries with subtle improvement in volume. Younger patients exhibited greater relative volume increases, highlighting the effectiveness of early interventions in achieving substantial corrections. Conclusion: This study underscores the unintentional yet impactful role of these surgeries in enhancing orbital volume alongside skeletal realignment. By demonstrating these additional benefits, it lays the groundwork for future investigations into optimizing craniofacial procedures for both functional and aesthetic outcomes through personalized surgical strategies and advanced planning tools.

References: 1. Katzen JT, McCarthy JG. Syndromes involving craniosynostosis and midface hypoplasia. Otolaryngol Clin North Am. 2000 Dec;33(6):1257-84, vi. doi: 10.1016/s0030-6665(05)70280-2. PMID: 11449786. 2. Richardson, D., Thiruchelvam, J. Craniofacial surgery for orbital malformations. Eye 20, 1224–1227 (2006). https://doi.org/10.1038/sj.eye.6702475 3. Grauer D, Cevidanes LS, Proffit WR. Working with DICOM craniofacial images. Am J Orthod Dentofacial Orthop. 2009 Sep;136(3):460-70. doi: 10.1016/j.ajodo.2009.04.016. PMID: 19732681; PMCID: PMC2761026. 4. Tiwana PS, Turvey TA. Subcranial procedures in craniofacial surgery: the Le Fort III osteotomy. Oral Maxillofac Surg Clin North Am. 2004 Nov;16(4):493-501. doi: 10.1016/j.coms.2004.08.001. PMID: 18088750. 5. Mendonca, Derick; Gejje, Somashekar; Kaladagi, Nitin. Fronto-orbital advancement: Revisited. Journal of Cleft Lip Palate and Craniofacial Anomalies 2(1):p 20-26, Jan–Jun 2015. | DOI: 10.4103/2348-2125.150739

Background: Overcorrection for trigonocephaly has been reported to achieve better shape outcomes for trigonocephaly.1 The aim of this study was to quantify cranial shape and measure the effect of fronto-orbital advancement (FOA) on 2-year bandeau shape in metopic craniosynostosis (MCS). Methods: A retrospective chart review was conducted to identify patients who underwent FOA for metopic synostosis. Patients with inadequate imaging were excluded. A control cohort of age-matched patients with no craniofacial abnormalities were used as shape comparison. Preoperative, immediate postoperative and 2-year postoperative computed tomography (CT) scans were annotated, cephalometric measurements and axial vectors at the level of bandeau were automatically calculated. A circularity measure was devised to evaluate the axial contour at the level of bandeau. On postoperative CTs, the advancement distances at the osteotomy were recorded near both zygomaticofrontal (ZF) sutures and nasion. Bivariate and multiple linear regression analyses were completed. A p-value < 0.05 was considered significant. Results: CT data at 3 timepoints for 88 patients with MCS, 84 CT scans for control and 74 scans for 2-yr control cohorts were included. Age at FOA was 10.7 months (±2mo). Preoperatively, MCS group had significantly lower circularity score than matched controls. After FOA, the circularity of MCS group increased but relapsed slightly at 2-year follow-up. At 2-year follow-up MCS group still had higher circularity scores than matched control cohort, indicating rounder forehead shape. In linear regression models, preoperative circularity score was a significant predictor of 2-year circularity score (p=0.02), while advancement distance and age were not (p=0.60 and p=0.88). Further analysis revealed that, advancement distance was negatively correlated with preoperative circularity (correlation coefficient=-0.33, p=0.004).
Conclusions: FOA is effective in normalizing cranial shape in metopic synostosis with favorable morphometric outcomes at 2-year follow-up. We utilized a circularity score to quantify the forehead shape. Cranial shape improved from preop to postop across MCS and comparable to controls at 2-year postop even with a slight relapse. Our longitudinal analysis found that the magnitude of advancement and shape correction negatively correlated with preoperative severity, where more severe trigonocephaly indicated further advancement and reshaping of the bandeau. Our multi-variable regression models revealed that preoperative severity was predictive of 2-year postoperative shape. References: 1. Patel KB, Skolnick GB, Mulliken JB. Anthropometric Outcomes following Fronto-Orbital Advancement for Metopic Synostosis. Plast Reconstr Surg. 2016 May;137(5):1539-1547.

Background: Overcorrection for trigonocephaly has been reported to achieve better shape outcomes for trigonocephaly.1 The aim of this study was to quantify cranial shape and measure the effect of fronto-orbital advancement (FOA) on 2-year bandeau shape in metopic craniosynostosis (MCS). Methods: A retrospective chart review was conducted to identify patients who underwent FOA for metopic synostosis. Patients with inadequate imaging were excluded. A control cohort of age-matched patients with no craniofacial abnormalities were used as shape comparison. Preoperative, immediate postoperative and 2-year postoperative computed tomography (CT) scans were annotated, cephalometric measurements and axial vectors at the level of bandeau were automatically calculated. A circularity measure was devised to evaluate the axial contour at the level of bandeau. On postoperative CTs, the advancement distances at the osteotomy were recorded near both zygomaticofrontal (ZF) sutures and nasion. Bivariate and multiple linear regression analyses were completed. A p-value < 0.05 was considered significant. Results: CT data at 3 timepoints for 88 patients with MCS, 84 CT scans for control and 74 scans for 2-yr control cohorts were included. Age at FOA was 10.7 months (±2mo). Preoperatively, MCS group had significantly lower circularity score than matched controls. After FOA, the circularity of MCS group increased but relapsed slightly at 2-year follow-up. At 2-year follow-up MCS group still had higher circularity scores than matched control cohort, indicating rounder forehead shape. In linear regression models, preoperative circularity score was a significant predictor of 2-year circularity score (p=0.02), while advancement distance and age were not (p=0.60 and p=0.88). Further analysis revealed that, advancement distance was negatively correlated with preoperative circularity (correlation coefficient=-0.33, p=0.004).
Conclusions: FOA is effective in normalizing cranial shape in metopic synostosis with favorable morphometric outcomes at 2-year follow-up. We utilized a circularity score to quantify the forehead shape. Cranial shape improved from preop to postop across MCS and comparable to controls at 2-year postop even with a slight relapse. Our longitudinal analysis found that the magnitude of advancement and shape correction negatively correlated with preoperative severity, where more severe trigonocephaly indicated further advancement and reshaping of the bandeau. Our multi-variable regression models revealed that preoperative severity was predictive of 2-year postoperative shape. References: 1. Patel KB, Skolnick GB, Mulliken JB. Anthropometric Outcomes following Fronto-Orbital Advancement for Metopic Synostosis. Plast Reconstr Surg. 2016 May;137(5):1539-1547.

Background: The free fibula osteocutaneous flap has become a cornerstone in reconstructive head and neck surgery, particularly for mandibular and maxillary reconstructions. While the procedure is known for its reliability and low complication rate, donor site complications, such as motor weakness in the great toe, have been reported. This weakness is typically due to damage to the nerve supplying the extensor hallucis longus (EHL) muscle, responsible for dorsiflexion of the great toe. This study aims to investigate anatomical variations of the nerve to the EHL and evaluate strategies for minimizing nerve injury during flap harvest. Methods: A prospective study was conducted at a tertiary cancer care institute between January 2024 and June 2024, involving 62 patients who underwent free fibula flap harvest for mandibular or maxillary reconstruction. The course of the deep peroneal nerve and its branches to the EHL muscle were identified using a nerve stimulator to facilitate precise nerve preservation. Key anatomical measurements were recorded, and postoperative functional assessments of the great toe were performed. For comparative analysis, a retrospective cohort of 580 patients who underwent fibula flap harvest without nerve identification (Group B) was also included. Results: The study revealed significant anatomical variability in the nerve supply to the EHL, with the nerve located most frequently on the tibial side (48.3% for the first branch and 53.5% for the second branch). Postoperative isolated EHL weakness occurred in only 1 patient (1.6%) in the experimental cohort, with full recovery within 6 months. In contrast, in the retrospective cohort, 2.06% of patients developed EHL weakness, with 0.86% experiencing complete recovery. Statistical analysis showed no significant difference between the two groups (p=0.11). Conclusions: This study demonstrates that careful identification and preservation of the nerve to the EHL significantly reduces the risk of postoperative functional deficits after free fibula flap harvest. Despite low incidence of weakness, our results emphasize the importance of understanding the nerve's anatomical variations and employing meticulous surgical techniques to protect it, thus enhancing patient outcomes and minimizing motor deficits. Further refinement of surgical strategies and individualized approaches may further optimize outcomes in future cases.

Introduction: Mandibular distraction osteogenesis (MDO) is a critical intervention for addressing severe upper airway obstruction in infants with Robin Sequence (RS). Nevertheless, this procedure carries a risk of facial nerve dysfunction (FND), particularly affecting the marginal mandibular nerve (MMN). Since 2019, our group has routinely monitored real-time facial nerve conduction using electroneuronography (ENoG) during MDO procedures. This pilot study evaluates nerve conduction changes during MDO procedures and their potential association with postoperative clinically visible FND. Methods: Nine infants with RS undergoing MDO from 2019 to 2024 were randomly selected. ENoG recorded motor responses from the orbicularis oculi and mentalis muscles. Significant changes were defined as peak latency increase of ≥10% or an amplitude decrease of ≥60% from baseline. Results: Twenty-five unilateral procedures [osteotomy/placement of hardware (18); hardware removal (6); revision (1)] were analyzed by a certified ENoG technician. Median age at surgery was 11.4 months (IQR 2.4, 42.7). Retraction during osteotomy was the surgical step most associated with a significant amplitude decrease in 83.3% of cases, while device activation caused the most frequent peak latency increase in 44.4% of cases. Temporary MMN dysfunction was observed in 4 postoperative clinical exams (16.7%). Sensitivity/Specificity were 17.6%/87.5% while NPV was 84.8%. Conclusion: This pilot study suggests that the intraoperative risk of MMN injury during MDO is greatest during retraction during osteotomy and device activation. With a NPV of 84.8%, ENoG shows promise in reliably predicting the absence of postoperative FND. Further research is necessary to confirm its utility in mitigating FND risks.

Purpose: Squamosal craniosynostosis (SQS) is a rare form of craniosynostosis characterized by the premature fusion of the minor squamosal suture. Unlike more commonly studied forms of craniosynostosis, SQS remains poorly understood due to its limited reported incidence. Consequently, its pathological effects on cranial morphology and intracranial volume (ICV) have not been thoroughly examined. This study aims to assess the volumetric effects of squamosal craniosynostosis on intracranial compartments using three-dimensional computed tomography (CT) analysis to identify anatomical regions most affected by this condition and provide a foundation for targeted reconstructive strategies. Methods: A retrospective analysis was conducted on patients diagnosed with SQS at a single institution between 2012 and 2024. Eight patients with confirmed squamosal craniosynostosis were identified and matched to age- and sex-matched controls selected from a normative cranial imaging database. High-resolution head CT scans were obtained for all subjects, and volumetric analyses were performed using Syngo.via software. Cranial indices (CI) and intracranial volume measurements, including total intracranial volume and compartmental volumes (anterior, middle, and posterior cranial compartments), were extracted for comparison. Paired t-tests were employed to assess statistical differences between patients with SQS and their respective control counterparts. Results: Analysis of cranial indices and intracranial volumes revealed an overall trend of lower cranial indices and reduced intracranial volumes in patients with squamosal craniosynostosis compared to age-sex-matched controls. However, while reductions in volume were observed across multiple compartments, only specific volumetric measurements demonstrated statistically significant differences. The most pronounced reductions were found in the middle and posterior cranial compartments, as well as in the total intracranial volume. The middle compartment volume was significantly decreased in patients with SQS compared to controls (p = .03). Similarly, the posterior cranial compartment volume was significantly lower in affected patients (p = .006). Finally, total intracranial volume was significantly lower in patients with SQS compared to their matched controls (p = .03). Conclusions: Our preliminary findings demonstrate that squamosal craniosynostosis is associated with a significant reduction in intracranial volume, primarily affecting the middle and posterior cranial compartments. These findings suggest that SQS may alter normal skull development in ways that could have clinical implications, particularly regarding cranial vault expansion and potential elevations in intracranial pressure. While the clinical significance of these volume deficits remains to be fully elucidated, the results of this study provide an anatomical basis for considering targeted surgical intervention when indicated. Future research with larger patient cohorts and long-term neurocognitive assessments will be necessary to further define the implications of these findings and refine treatment strategies for this rare craniosynostosis subtype.

Wagner C, Pontell M, Reddy N, Salinero L, Barrero C, Swanson J, Taylor J, Bartlett SP. Isolated Squamosal Craniosynostosis: Considerations of Presentation, Intracranial Pressure, and Management. Plast Reconstr Surg Glob Open. 2023 Oct 18;11(10 Suppl):140-141. doi: 10.1097/01.GOX.0000992636.42120.95. PMCID: PMC10566778. Fallahian F, Meyer A, Tadisina KK, Lin AY. Surgical Management in Isolated Squamosal Craniosynostosis: A Systematic Review. Ann Plast Surg. 2023 Oct 1;91(4):493-496. doi: 10.1097/SAP.0000000000003642. Epub 2023 Aug 12. PMID: 37553899.

Purpose: The purpose of this study was to characterize antibiotic prophylaxis practices in pediatric patients who have received cranial vault remodeling surgery and understand how these practices impact 30-day postoperative infection rates. Methods: This was a retrospective cohort study using the National Surgical Quality Improvement Program Pediatric database for years 2021 and 2022. Patients 18 years of age or younger who received cranial vault remodeling were included. Current Procedural Terminology (CPT) codes used included 61558, 61559, 61550, 61552, 61557, and 21175. The outcome of interest was 30-day postoperative surgical site infection (SSI), deep, and organ or space levels. Fisher's exact test and multivariable regression analysis were used to analyze the impact of intravenous antibiotic prophylaxis, intraoperative intravenous antibiotic redosing, postoperative antibiotic prophylaxis, and various antibiotic prophylaxis regimens. Results: A total of 2,598 patients were included in this study, of which 2,565 (98.7%) received preoperative IV antibiotic prophylaxis, while 644 (25.1%) underwent intraoperative antibiotic redosing, and 1,789 (69.7%) had postoperative antibiotics continued after the procedure. The most commonly used primary antibiotics were Cefazolin (92.1%), Clindamycin (2.4%), Cefuroxime (1.5%), and Vancomycin (1.1%). A total of 49 instances of SSIs were observed, resulting in an overall infection rate of 1.88%, with 36 being superficial, 11 deep, and 2 organ-space infections. All patients with infections had received preoperative antibiotics, but none had received intraoperative redosing.

Statistical analysis revealed that preoperative IV antibiotic prophylaxis was not significantly associated with a reduction in SSIs, as demonstrated by the following p-values: Superficial SSI (p = 0.433), Deep Incisional SSI (p = 0.719), and Organ-Space SSI (p = 0.873). Similarly, intraoperative antibiotic redosing (p = 0.719) and postoperative antibiotic continuation (p = 0.433) did not significantly alter SSI rates. Multivariable logistic regression adjusting for age, sex, and procedure type further confirmed that none of the antibiotic regimens significantly reduced the likelihood of developing a postoperative SSI (adjusted OR = 1.03, 95% CI: 0.76–1.39, p = 0.873).

Conclusions: We found that prophylactic IV antibiotic use did not significantly alter the rates of 30-day surgical site infections in pediatric cranial vault remodeling procedures. Results from this study can serve as the basis for further investigation to standardize antibiotic use and stewardship in pediatric craniofacial care.

Purpose: The purpose of this study was to characterize antibiotic prophylaxis practices in pediatric patients who have received cranial vault remodeling surgery and understand how these practices impact 30-day postoperative infection rates. Methods: This was a retrospective cohort study using the National Surgical Quality Improvement Program Pediatric database for years 2021 and 2022. Patients 18 years of age or younger who received cranial vault remodeling were included. Current Procedural Terminology (CPT) codes used included 61558, 61559, 61550, 61552, 61557, and 21175. The outcome of interest was 30-day postoperative surgical site infection (SSI), deep, and organ or space levels. Fisher's exact test and multivariable regression analysis were used to analyze the impact of intravenous antibiotic prophylaxis, intraoperative intravenous antibiotic redosing, postoperative antibiotic prophylaxis, and various antibiotic prophylaxis regimens. Results: A total of 2,598 patients were included in this study, of which 2,565 (98.7%) received preoperative IV antibiotic prophylaxis, while 644 (25.1%) underwent intraoperative antibiotic redosing, and 1,789 (69.7%) had postoperative antibiotics continued after the procedure. The most commonly used primary antibiotics were Cefazolin (92.1%), Clindamycin (2.4%), Cefuroxime (1.5%), and Vancomycin (1.1%). A total of 49 instances of SSIs were observed, resulting in an overall infection rate of 1.88%, with 36 being superficial, 11 deep, and 2 organ-space infections. All patients with infections had received preoperative antibiotics, but none had received intraoperative redosing.

Statistical analysis revealed that preoperative IV antibiotic prophylaxis was not significantly associated with a reduction in SSIs, as demonstrated by the following p-values: Superficial SSI (p = 0.433), Deep Incisional SSI (p = 0.719), and Organ-Space SSI (p = 0.873). Similarly, intraoperative antibiotic redosing (p = 0.719) and postoperative antibiotic continuation (p = 0.433) did not significantly alter SSI rates. Multivariable logistic regression adjusting for age, sex, and procedure type further confirmed that none of the antibiotic regimens significantly reduced the likelihood of developing a postoperative SSI (adjusted OR = 1.03, 95% CI: 0.76–1.39, p = 0.873).

Conclusions: We found that prophylactic IV antibiotic use did not significantly alter the rates of 30-day surgical site infections in pediatric cranial vault remodeling procedures. Results from this study can serve as the basis for further investigation to standardize antibiotic use and stewardship in pediatric craniofacial care.

Purpose: Facial Vascularized Composite Allotransplantation (fVCA) has emerged as a transformative solution for patients with severe facial disfigurement. Current Department of Defense funding aims to standardize indications, management, and outcomes collection in hand and face transplantation. With the 20th anniversary of the first face transplantation in November 2024, we aim to provide a comprehensive overview of our institutional protocol for face transplantation based on decades of clinical and research experience and the largest cohort of transplant patients, aiming to support this effort. Methods: We outline the essential components of the authors' protocol for face transplantation, including a step-by-step guide for program establishment, patient selection, donor screening, preoperative evaluation, surgical planning, immunosuppression and prophylactic therapy regimens, and long-term follow-up for patient outcomes. Results: The development of our face transplantation program is anchored in a robust multidisciplinary collaboration. Key program components include rigorous patient and donor selection criteria, meticulous surgical planning using 3D cutting guides, and comprehensive immunosuppressive and antimicrobial regimens pre and post-transplant. Our protocol also emphasizes long-term follow-up, focusing on functional recovery, aesthetic outcomes, and psychological well-being, and a comprehensive rehabilitation regimen. Conclusions: Despite substantial progress, challenges remain in optimizing immunosuppressive protocols, improving rejection detection, and establishing standardized guidelines for follow-up care. Future research should focus on personalized immunosuppressive strategies and refining long-term outcome tracking. Collaborative efforts across institutions are necessary to establish evidence-based practices and further enhance the success of face transplantation programs globally.

Purpose: Electric bicycle and scooter use has greatly expanded in major urban areas changing the public transit landscape and intersection traffic. This study reports injury patterns associated with micromobility vehicles treated at Level I trauma center located in a large urban city. This analysis includes incidence and nature of these injuries related to both the operators of the vehicles and the pedestrians stuck.

Methods: A single-institution, retrospective review of all patients presenting to an urban level I trauma hospital from January 2022 to December 2024 with an injury associated with a micromobility vehicle. Patients were identified from the trauma registry and only patients with craniomaxillofacial injuries were included. Patients' medical records were reviewed to assess age, gender, ethnicity, type of device, mechanism, use of protective gear, speed, Injury Severity Score (ISS), substance abuse, alcohol use, disposition from emergency department, operative intervention(s), hospital length of stay, and ICU length of stay. In addition to the operators of the micromobility vehicles, pedestrians stuck were also included in this analysis.

Results: 91 patients were included in the study over a two-year period: 17 electronic bike operators, 24 electronic scooter operators, and 50 pedestrians struck. Electronic bike operators had an average age of 32.3, 88% male, averaged 13.35 injury severity score, and 35% were helmeted. Of the patients with craniofacial trauma, injuries included: intracranial bleed (41%), skull fracture (35%), facial fracture (47%), and craniofacial laceration (35%). Electronic scooter operators had an average age of 42.5, 88% male, Injury severity score of 13.6, and 21% helmeted. Of the patients with craniofacial trauma, injuries included: intracranial bleed (58%), skull fracture (16%), facial fracture (29%), and craniofacial laceration (70%). Subset analysis of patients for helmet use across all micromobility operators demonstrated that helmets reduced: injury severity score, ICU length of stay, hospital length of stay, intubation rate on arrival, intracranial hemorrhage rates, and skull fracture rates. 5 E-scooter patients required decompressive craniotomy compared to 1 E-bike patient. Additionally, 2 E-scooter patients required mandibular fixation, and 1 E-bike patient required zygomatic fracture fixation. Of note, only non-helmeted patients required surgical intervention for craniofacial injuries. Pedestrian struck patients had an average age of 50.22, 48% male, ISS 13.62. Injury patterns included the highest rates of intracranial trauma: 38 intracranial bleeds (76%), 20 skull fractures (40%), and 11 facial fractures (22%). 2 patients underwent decompressive craniotomy.

Conclusions: Motorized micromobility vehicles are associated with significant injuries. The frequent occurrence of concomitant injuries to the craniomaxillofacial region highlights substantial safety concerns. Helmet use reduced injury severity score, length of stay, ICU stay, and risk to intracranial injury. Pedestrians account for over 50% of occurrences and include the highest rate of intracranial injury.

Purpose: Chin is the most prominent feature of the lower face, and it considerably affects the overall facial attractiveness and harmony.[1,2] A broad and square chin is considered aesthetically unpleasing, and a small and slightly protruded chin is deemed attractive among East Asian women.[3-5] Therefore, advancement and narrowing genioplasty is often performed. We have adopted the step genioplasty using trapezoid osteotomy for this purpose, where trapezoid-shaped osteotomized chin bone is placed onto the cephalic bony step. We present the surgical procedures and evaluate the outcomes. Methods: We retrospectively reviewed consecutive patients who received genioplasty between January 2019 and December 2023. Details regarding patient demographics, surgical procedures, and postoperative complications were collected. Lateral cephalometric images were obtained before, immediately after, and at least 6 months after the genioplasty, and measured to evaluate the relapse rate and soft tissue response ratio. Results: A total of 145 patients (127 females and 18 males) received the step genioplasty using trapezoid osteotomy during the study period, with the mean age of 31.0 ± 7.9 years at the time of operation. The mean followed-up period was 17.4 ± 12.8 months postoperatively. Seventy-five patients underwent bimaxillary surgery simultaneously, and 36 patients received other facial bone contouring procedures concomitantly. The remaining 34 patients had genioplasty with or without plate removal. The amount of chin advancement and shortening were 5.3 ± 2.0 and 3.4 ± 1.4 mm, respectively. No patient developed major complications, such as infection, intraoperative or postoperative bleeding, or permanent paresthesia of the chin. Some patients reported mild neurosensory disturbance postoperatively. Lateral cephalogram showed that the efficacy of the genioplasty on chin advancement: the mean soft-to-hard tissue ratio was 0.93:1, and bony relapse was minimal with only 3.0%. Conclusion: The step genioplasty using trapezoid osteotomy was considered to be a highly effective technique with several advantages. The bony step served as a stay and facilitated intraoperative assessment. It also supported to stabilize the bony segment, reducing the risk of postoperative bony relapse. The trapezoid-shaped osteotomy enabled to narrow the chin sufficiently, maintaining the vascularity to the osteotomized bone. This method is a viable option for advancement and narrowing osseous genioplasty.

1. Guyuron B. MOC-PS(SM) CME article: Genioplasty. Plast Reconstr Surg. 2008;121:1-7.
2. Naran S, Steinbacher DM, Taylor JA. Current concepts in orthognathic surgery. Plast Reconstr Surg. 2018;141:925-936.
3. Park S, Noh JH. Importance of the chin in lower facial contour: Narrowing genioplasty to achieve a feminine and slim lower face. Plast Reconstr Surg. 2008;122:261-268.
4. Rohrich RJ, Sanniec K, Afrooz PN. Autologous fat grafting to the chin: A useful adjunct in complete aesthetic facial rejuvenation. Plast Reconstr Surg. 2018;142:921-925.
5. Sati S, Havlik RJ. An evidence-based approach to genioplasty. Plast Reconstr Surg. 2011;127:898-904.

Background Face transplant rejection is primarily monitored through skin biopsies, but mucosal biopsies may detect immune rejection events missed by skin samples, raising concerns about relying solely on cutaneous assessments. This study evaluates the correlation between rejection grades in mucosal, facial skin, and sentinel flap biopsies, aiming to improve rejection monitoring protocols in facial vascularized composite allotransplantation (fVCA).

Methods A retrospective review of 47 paired mucosal and facial skin biopsies and 37 paired facial skin and sentinel flap biopsies was conducted from nine face transplant recipients. Rejection was graded using the 2007 Banff classification for skin and an adapted grading system for mucosa. Statistical analysis included correlation assessments, sensitivity and specificity metrics, and predictive value calculations.

Results Mucosal and facial skin rejection grades correlated strongly (r=0.72, p<0.0001), with mucosal biopsies demonstrating a negative predictive value (NPV) of 0.85 for skin rejection. Mucosal biopsies identified rejection in 10 cases missed by facial skin biopsies, while isolated skin rejection was rare and clinically insignificant. Sentinel skin biopsies correlated well with facial skin biopsies but had an NPV of 0.76, missing 25% of rejection cases.

Conclusion Mucosal biopsies may offer greater sensitivity in detecting immune activity compared to skin biopsies. However, as mucosal rejection did not invariably precede skin rejection in all patients, mucosa may serve as an early marker, though its long-term clinical significance remains uncertain. Our findings thus support integrating mucosal biopsies into routine rejection monitoring while maintaining the relevance of skin biopsies. Given the limited reliability of sentinel skin biopsies in predicting facial skin rejection, their necessity warrants reconsideration.

Purpose:

Current guidelines recommend < 24 hours of antibiotic prophylaxis (AP) for operative mandibular fractures. However, these guidelines are based on limited patient populations and weak evidence. This study evaluates the effects of AP in GSW-related mandibular fractures.

Methods:

Patients with GSW-related mandibular fractures who presented to a level 1 trauma center (2013-2024) were included. Demographics, clinical characteristics, AP use, and infection rates were collected. Patients were grouped into non-AP and AP cohorts.

Results:

A total of 133 patients were included: 51 (38.3%) had isolated mandibular fractures and 82 (61.6%) had mandibular and concurrent craniofacial fractures. Of these patients, 114 (85.7%) had AP, while 19 (14.2%) had no AP. Both cohorts had similar demographics: mean age 33 (non-AP) vs. 37.4 years (AP) and male predominance (82.7% (non-AP) and 85.2% (AP)).

The overall infection rate was 15% (n = 20/133). The non-AP cohort had higher infection rates than the AP cohort (57.9% vs. 7.89%, p < 0.001). In the isolated mandibular fractures, the total infection rate was 13.7% (n = 7). The non-AP cohort had a a higher infection rate than the AP cohort (50% vs. 8.8%, p = 0.028). Similarly, for mandibular with concurrent craniofacial fractures, total infection rate was 15.9% (n = 13) and the non-AP cohort had higher infection rates than the AP cohort (61.5% vs. 7.25%, p < 0.001).

Conclusions:

In this study, GSW-related mandibular fractures have a 50 - 60% risk of infection without AP. AP significantly reduces infection rates, warranting guideline revision for this population.

Background Up to 30% of patients undergoing primary palatoplasty require secondary surgery due to velopharyngeal insufficiency. In patients with a large pharyngeal gap seen on nasoendoscopy, surgical intervention may risk the development of obstructive sleep apnea. This study reports a novel Arrow Revision Palatoplasty (ARP), a technique that combines revision palatoplasty and buccal flaps to concurrently reconstruct the levator sling and lengthen the palate without the creation of obstructive flaps within the pharynx. Methods A retrospective chart review of all patients undergoing ARP by the senior author between 06/2021 and 06/2024 was performed. Preoperative video speech nasopharyngeal endoscopy were rated by a certified speech language pathologist who also performed perceptual speech analysis on all patients, and rated their hypernasality, hyponasality, and audible nasal emission in accordance with the Americleft Speech Clinical Rating Form. Speech scores were described using median (IQR), and postoperative scores for patients were treated as paired data and assessed using paired samples Wilcoxon test. p<0.05 was considered statistically significant. Results Eleven patients were included in this study. Average age at time of ARP was 16 (SD 7) years. Patients on average underwent 1.5 (SD 0.7) prior palatal surgeries. Nasoendoscopies were available for 9 (82%) patients preoperatively and 6 (55%) patients postoperatively. The median ratio of velopharyngeal sphincter closure was 0.4 preoperatively and increased to 0.95 postoperatively (Figure 1). Perceptual speech analysis was available for 4 (36%) patients preoperatively and 7 (64%) patients postoperatively. Median preoperative hypernasality was 2.25, which corresponds to mild-moderate hypernasality and improved to 1 (borderline/minimal) postoperatively. Hyponasality was consistently 0 (absent) for all patients. Median audible nasal emission was 2 (frequently noted) preoperatively and improved to 1 (occasionally/seldom noted) postoperatively. Conclusion Arrow revision palatoplasty can improve pharyngeal gap and speech outcomes in patients with a cleft and velopharyngeal insufficiency associated with a large pharyngeal deficiency. This technique should be considered for patients with challenging velopharyngeal insufficiency that is at higher risk for developing surgical-induced obstructive sleep apnea.

Purpose: Three-dimensional printed (3DP) bioceramic scaffolds composed of beta-tricalcium phosphate (β-TCP), which possess an interconnected porous architecture, have previously demonstrated the ability to promote bone regeneration across critically-sized calvarial defects. Cranioplasty procedures, however, are often performed when the dura mater is scarred, compromised, or absent, reducing the potential for dura-mediated osteoinduction. This study evaluates whether the interconnected porosity of 3DP β-TCP scaffolds alone is sufficient to support bone regeneration across critically-sized calvarial defects in the absence of dura-mediated osteoinduction.

Methods: Critical-sized, 11mm unilateral calvarial defects were created in skeletally mature rabbits (n=11). Following defect creation, each rabbit received one of two scaffold designs in the defect: (i) a 3DP β-TCP scaffold with a solid, nonporous cap on the inferior surface, preventing direct contact between the scaffold's porous structure and the dura mater, or (ii) a scaffold with a fully porous inferior surface, allowing direct interaction with the dura and enabling dura-mediated osteoinduction. The animals were euthanized 8 weeks postoperatively, and calvarial samples were harvested for analysis. Qualitative morphometric and quantitative volumetric analysis was performed using histology and micro-computed tomography (μCT) imaging, respectively, to evaluate bone, soft tissue, and scaffold. Data was analyzed using generalized linear mixed model, with fixed factor variable of scaffold design (closed versus open), reported as mean and 95% confidence interval.

Results: Volumetric analysis revealed no significant differences between scaffold designs regarding bone volume (open: 9.3% ± 4.5 vs. closed: 10.2% ± 4.5; p=0.71), soft tissue volume (open: 58.5% ± 7.0 vs. closed: 52.5% ± 2.0; p=0.07), or scaffold volume (open: 32.3% ± 3.4 vs. closed 37.3% ± 4.3; p=0.92). Both scaffold designs demonstrated successful bridging bone across the calvarial defects, irrespective of the scaffold design. Qualitative histological analysis revealed vascularized bone within the scaffold with presence of Haversian canals.

Conclusion: This pilot study demonstrated that 3DP β-TCP scaffolds with an interconnected porous architecture facilitate bone regeneration across critically-sized calvarial defects, even without dura-mediated osteoinduction. Both scaffold designs, whether a porous or solid cap, resulted in analogous levels of bone formation, indicating that osteoconduction through the scaffold's interconnected pores is a sufficient mechanism to support bone regeneration. These findings suggest that 3DP bioceramic scaffolds have the potential to serve as an effective alternative to traditional bone grafts in cranioplasty procedures, particularly when the dura is absent or compromised. The results from this pilot study could inform future designs of tissue-engineered scaffolds for cranial reconstruction, offering a potential solution for patients with scarred or missing dura.

Introduction: To better expand the anterior cranial fossa and account for growth and relapse after traditional front-orbital advancement (FOA), an intentional "overcorrection" technique was adopted by our institution in 2012. This study compares the complications, revisions, and long-term aesthetic outcomes between the "traditional" FOA (T-FOA) and "overcorrection" FOA (O-FOA) approaches for isolated metopic craniosynostosis. Methods: A retrospective review was performed of all children who underwent FOA for isolated metopic craniosynostosis from 1987 to 2020 at our institution. Patients with ≥4 years follow-up were included. The Whitaker classification system (I being highest suggesting no revision, IV being lowest suggesting need for major revision) was used for aesthetic assessment.
Results: Of the 270 patients who underwent surgical correction of isolated metopic synostosis, 161 (61.5%) patients met inclusion criteria (n=100 (60.2%) T-FOA and n=66 (39.8%) O-FOA). Mean age at surgery was 10.9±6.3 months with follow-up of 9.5±4.1 years. The O-FOA cohort had similar preoperative (73.5±7.6 vs 75.6±6.1 mm, p=0.098) bitemporal widths, however postoperative (100.1±6.9 vs 91.9±7.5, p<0.001) and absolute difference in increase in bitemporal width (18.0±5.1 vs 24.8±5.4, p<0.001) were higher in the O-FOA cohort. There were 13 (7.8%) surgical complications, and 40 (24.1%) patients underwent at least one secondary surgery, more commonly in the T-FOA cohort (35.0% vs 7.6%, p<0.001). In the intermediate term, patients who underwent T-FOA had higher Whitaker scores (2.2±1.0 vs 1.5±0.8, p<0.001) and were more likely to have palpable bony irregularities (64.0% vs 21.2%, p<0.001), visible irregularity (68.0% vs 48.5%, p=0.012), and lateral orbital retrusion (48.0% vs 15.2%, p<0.001) compared to O-FOA. However, in subgroup analysis of patients ≥10 years old postoperatively (n=85), aesthetic outcomes (Whitaker 2.1±1.0 vs 2.4±1.0, p=0.167) and revisions (48.6 vs 26.7%, p=0.122) were comparable between the two cohorts. Follow-up time was found to be predictive of need for revision (β=0.054, p<0.001), higher Whitaker score (β=0.079, p<0.001), and temporal hollowing (β=0.038, p=0.001) independent of age at intervention, surgical technique, use of interpositional grafts, lateral canthopexy, or resorbable fixation, surgeon, and demographic factors. Conclusion: Despite incorporation of a more aggressive attempt to bitemporally "overcorrect" metopic deformity at time of frontal orbital advancement, similar levels of aesthetic deterioration were seen in patients 10 years or older at follow-up. Though safe and effective at achieving its primary surgical goals with improved aesthetic scores in the intermediate-term follow-up, the FOA technique, even with overcorrection, is associated with a high incidence of aesthetic deformity over time.

Objectives: Impaired glymphatic drainage causes a glymphedema, a condition similar to lymphedema elsewhere in the body(1). Glymphatic dysfunction has been recently associated with neurodegenerative disease (ND) such as Alzheimer's disease, Parkinson's disease, and several other entities(2). Vascularized lymph node transfer has shown benefits to lymphatic drainage outside the central nervous system in both human and animal models(3,4). We hypothesize that vascularized lymph node transfer (VLNT) can be utilized to develop a secondary means of glymphatic drainage and may provide a surgical option for the treatment of ND in the future.

Methods: Long Evans adult male rats were studied using VLNT transfer from the axillary/cervical lymph node basin and placed over the dura/meninges following vertex hemi-craniectomy. After allowing one week for maturation, 100 µl of Evans blue dye (EBD) was injected into the cisterna magna and glymphatic drainage was measured at 4 hours post-EBD injection. Rat brains were sectioned into the right and left hemispheres, and the cerebellum and lysed using radioimmunoprecipitation (RIPA) buffer. Lysate color absorbances were measured at 608 nm (EBD wavelength) for each of the 3 experimental central nervous system (CNS) locations and compared to control rats.

Results: Six rats were investigated. 608 nm color absorbance measures were performed for the left hemisphere brain lysates measuring 0.11 ± 0.02 absorbance units (AU) in VLNT group and 0.19 ± 0.04 AU in controls. For the right hemisphere lysates,608 nm color absorbance measured 0.11± 0.02 AU in VLNT samples versus 0.18 ± 0.01 AU in controls. Cerebellum absorbance measures were 0.18± 0.03 AU in VLNT samples in comparison to 0.31 ± 0.06 AU in controls. Statistical analysis using a two-tailed T-test indicated a significant reduction in the right hemisphere EBD levels (p= 0.03), with other regions demonstrating trends approaching significance. There was detectable EBD content in the transferred lymph node, with an EBD absorbance of 0.13 ± 0.04 AU, indicating passage of glymphatic EBD from the CNS to the VLNT.

Conclusion: Our study demonstrates that VLNT augments glymphatic drainage of the CNS. This proof-of-concept study suggests that VLNT could be used as a potential surgical option for the treatment of glymphedema and its associated neurodegenerative disorders.

References: 1. Louveau A, Smirnov I, Keyes TJ, et al. Structural and functional features of central nervous system lymphatic vessels [published correction appears in Nature. 2016 Feb 24;533(7602):278. doi: 10.1038/nature16999.]. Nature. 2015;523(7560):337-341. doi:10.1038/nature14432 2. Nedergaard M, Goldman SA. Glymphatic failure as a final common pathway to dementia. Science. 2020;370(6512):50-56. doi:10.1126/science.abb8739 3. Raju A, Chang DW. Vascularized lymph node transfer for treatment of lymphedema: a comprehensive literature review. Ann Surg. 2015;261(5):1013-1023. doi:10.1097/SLA.0000000000000763 4. Ramos M, Burdon Bechet N, Battistella R, et al. Cisterna Magna Injection in Rats to Study Glymphatic Function. Methods Mol Biol. 2019;1938:97-104. doi:10.1007/978-1-4939-9068-9_7