Assessing Survival, Distribution, and Optimal Loading Technique of Schwann Cell-Derived Exosomes Into Second-generation Axon Guidance Channels.

INTRODUCTION: Peripheral nerve injury (PNI) occurs in approximately 3% of all trauma patients and can be challenging to treat, particularly when injury is severe such as with a long-segmental gap. Although peripheral nerves can regenerate after injury, functional recovery is often insufficient, leading to deficits in the quality of life of patients with PNI. Although nerve autografts are the gold standard of care, there are several disadvantages to their use, namely a lack of autologous nerve material for repair. This has led to the pursuit of alternative treatment methods such as axon guidance channels (AGCs). Second-generation AGCs have been shown to be able to deliver growth-enhancing substrates for nerve repair directly to the injury site. Although our laboratory has had success with second-generation AGCs filled with Schwann cells (SCs), SCs have their own set of issues clinically. Because of this, we have begun to utilize SC-derived exosomes as an alternative, as they have the appropriate protein markers, associate to axons in high concentrations, and are able to improve nerve regeneration. However, it is unknown how SC-derived exosomes may react within second-generation AGCs; thus, the aim of the present study was to assess the ability of SC-derived exosomes to be loaded into a second-generation AGC and how they would distribute within it. MATERIALS AND METHODS: A total of 4 dry second-generation AGCs were loaded with SC-derived exosomes that were derived from green fluorescent protein (GFP)-labeled SCs. They were subsequently frozen and sliced before imaging. RESULTS: Here, we present findings that SC-derived exosomes can be loaded into second-generation AGCs through our established loading method utilizing negative pressure and are able to survive and equally distribute along the length of the AGC. CONCLUSIONS: Although only 4 second-generation AGCs were utilized, these findings indicate a potential use for SC-derived exosomes within second-generation AGCs to treat severe PNI. Future research should focus on exploring this in greater detail and in different contexts to assess the ability of SC-derived exosomes to survive at the site of injury and treat PNI.

Management of Maxillofacial Trauma in Pregnant Women.

INTRODUCTION: Trauma during pregnancy deserves special attention as management must be directed towards both the mother and the fetus. Management of maxillofacial fractures in pregnancy can adversely affect the well-being of the fetus by impinging on normal functions such as respiration, mastication, and nutrition. Pregnancy complicates the management of facial injury due to the maintenance of the patent airway, anesthesia considerations, and imaging restraints. The purpose of this study is to use three illustrative from our own institution to further elucidate education on the management of mandible fracture in pregnancy with a focus on multidisciplinary treatment and outcomes. METHODS: A retrospective chart review was performed for all cases of facial fractures admitted to Ryder Trauma Center from 2012 to 2022. During this time, 4,910 patients presented with facial fractures 1319 patients were female. Three of the patients were pregnant at the time of admission. Demographics, mechanism of injury, associated injuries, and management information were collected. RESULTS: Patient 1 was a 20-year-old female presented to Ryder Trauma Center following a motor vehicle collision. She was 17 weeks pregnant at the time of admission and was found to have a left mandibular angle fracture. Patient 2 was a 14-year-old female who presented to Ryder Trauma Center status post gunshot wound to the mandible after she and her brother were unknowingly playing with a loaded gun. She was 18 weeks pregnant at the time of admission, with a past medical history of domestic violence, suicidal ideation, and major depressive disorder. Patient 3 was a 20-year-old female 36 weeks pregnant at the time of admission. She presented with a right paraymphyseal fracture and left mandibular angle fracture as a result of falling on the stairs. Patients all underwent surgical repair of fractures.

Prepectoral Direct-to-Implant versus Staged Tissue Expander Breast Reconstruction: A Comparison of Complications.

BACKGROUND: Direct-to-implant (DTI) reconstruction has multiple advantages over a staged tissue expander (TE) approach. However, its use may be limited by concerns of increased complications. This study is the largest series to date comparing postoperative outcomes for DTI versus TE reconstruction in the prepectoral plane. METHODS: The authors retrospectively reviewed 348 patients that received 536 total immediate, prepectoral implant-based breast reconstructions between January 2018 and December 2021. The authors compared the presence of risk factors and the rate of six separate complications between patients that received DTI versus TE reconstruction up to one year after surgery. RESULTS: Of 348 patients, 147 (42%) and 201 (58%) underwent TE and DTI reconstruction (p=0.1813), respectively. Overall infection rate was 16.4% (n=57). DTI patients had a significantly greater incidence of wounds (p<0.0001), including minor (p<0.0011) and major wounds (p<0.0053). Significantly greater mastectomy resection weights were found for DTI patients that experienced any complication (p<0.0076), postoperative wounds (p<0.0001), and major wounds specifically (p<0.0035). Compared to medium thickness, extra-thick acellular dermal matrix (ADM) was associated with significantly increased rates of infection (p<0.0408) and wounds (p<0.0001). CONCLUSIONS: Prepectoral DTI reconstruction in patients with adequate flap perfusion may have comparable complication rates to staged TE reconstruction apart from a higher incidence of postoperative wounds. Greater mastectomy resection weights and thickness of ADM may specifically contribute to infectious and wound-healing complications. Prepectoral DTI reconstruction is encouraged in the patients with adequate flap perfusion and moderate to low mastectomy resection weights that desire comparable or smaller implant volumes.

Clinical applications of electrical stimulation for peripheral nerve injury: a systematic review.

Introduction: Peripheral nerve injuries are common neurologic injuries that are challenging to treat with current therapies. Electrical stimulation has been shown to accelerate reinnervation and enhance functional recovery. This study aims to review the literature on clinical application of electrical stimulation for peripheral nerve injury. Methods: PubMed and Embase were sourced from 1995 to August 2022. Selection was based on predetermined inclusion/exclusion criteria. Eight hundred and thirty-five articles were screened with seven being included in this review. Results: Two hundred and twenty-nine patients with peripheral nerve injuries were represented. Six of the studies were randomized controlled trials. A variety of nerve injuries were represented with all being in the upper extremity and supraclavicular region. Electrical stimulation protocols and evaluation varied. Electrodes were implanted in four studies with one also implanting the stimulator. Length of stimulation per session was either 20 mins or 1 h. Median stimulation frequency was 20 Hz. Stimulation intensity varied from 3 to 30V; pulse width ranged from 0.1 to 1.007 ms. Three protocols were conducted immediately after surgery. Patients were followed for an average of 13.5 months and were evaluated using electrophysiology and combinations of motor, sensory, and functional criteria. Discussion: Patients who received electrical stimulation consistently demonstrated better recovery compared to their respective controls. Electrical stimulation for peripheral nerve injury is a novel treatment that has not been well-studied in humans. Our review illustrates the potential benefit in implementing this approach into everyday practice. Future research should aim to optimize protocol for clinical use.

Correlation Between Altmetric Scores and Citation Count in 4 High-Impact Plastic Surgery Journals.

BACKGROUND: The Altmetric Attention Score (AAS) aims to determine the impact of research articles throughout the internet and social media outlets. The AAS is a weighted average of the interaction on platforms including Twitter, Facebook, Reddit, and more. OBJECTIVES: The aim of this study was to investigate the relationship between the AAS and traditional bibliometrics across plastic surgery journals. METHODS: Articles, number of citations (NOC), and H-index information in Annals of Plastic Surgery (APS), Plastic and Reconstructive Surgery (PRS), Plastic and Reconstructive Surgery Global Open (PRS GO), and Aesthetic Surgery Journal (ASJ) from 2017, 2018, and 2019 were queried with the Scopus Online Tool. AAS metrics were collected with the Altmetric Score Calculator Bookmarklet. Descriptive statistics, Spearman rank-correlation analyses, and analyses of variance were performed to measure associations between NOC and AAS. RESULTS: A total of 3612 articles were analyzed. NOC was weakly correlated with AAS in APS, PRS GO, and ASJ, and moderately correlated with AAS in PRS. NOC was weakly correlated with Twitter mentions in APS, PRS GO, and ASJ, and moderately correlated in PRS. NOC was weakly correlated with news outlet reporting. The H-index of the first author showed more significant correlations with the AAS than the H-index of the last author. CONCLUSIONS: NOC and H-index of the first author correlated with AAS in the plastic surgery literature, suggesting AAS may be a useful adjunct to traditional bibliometrics when evaluating the impact and reach of peer-reviewed articles.

Systematic review of the therapeutic use of Schwann cells in the repair of peripheral nerve injuries: Advancements from animal studies to clinical trials.

Objective: To systematically evaluate the literature on the therapeutic use of Schwann cells (SC) in the repair of peripheral nerve injuries. Methods: The Cochrane Library and PubMed databases were searched using terms [("peripheral nerve injury" AND "Schwann cell" AND "regeneration") OR ("peripheral nerve injuries")]. Studies published from 2008 to 2022 were eligible for inclusion in the present study. Only studies presenting data from in-vivo investigations utilizing SCs in the repair of peripheral nerve injuries qualified for review. Studies attempting repair of a gap of ≥10 mm were included. Lastly, studies needed to have some measure of quantifiable regenerative outcome data such as histomorphometry, immunohistochemical, electrophysiology, or other functional outcomes. Results: A search of the PubMed and Cochrane databases revealed 328 studies. After screening using the abstracts and methods, 17 studies were found to meet our inclusion criteria. Good SC adherence and survival in conduit tubes across various studies was observed. Improvement in morphological and functional outcomes with the use of SCs in long gap peripheral nerve injuries was observed in nearly all studies. Conclusion: Based on contemporary literature, SCs have demonstrated clear potential in the repair of peripheral nerve injury in animal studies. It has yet to be determined which nerve conduit or graft will prove superior for delivery and retention of SCs for nerve regeneration. Recent developments in isolation and culturing techniques will enable further translational utilization of SCs in future clinical trials.

Optimal Technique for Introducing Schwann Cells Into Peripheral Nerve Repair Sites.

Peripheral nerve injury (PNI) is found in a relatively large portion of trauma patients. If the injury is severe, such as with the presence of a long segmental gap, PNI can present a challenge for treatment. The current clinical standard of nerve harvest for the repair of long segmental gap PNI can lead to many potential complications. While other methods have been utilized, recent evidence indicates the relevance of cell therapies, particularly through the use of Schwann cells, for the treatment of PNI. Schwann cells (SCs) are integral in the regeneration and restoration of function following PNI. SCs are able to dedifferentiate and proliferate, remove myelin and axonal debris, and are supportive in axonal regeneration. Our laboratory has demonstrated that SCs are effective in the treatment of severe PNI when axon guidance channels are utilized. However, in order for this treatment to be effective, optimal techniques for cellular placement must be used. Thus, here we provide relevant background information, preclinical, and clinical evidence for our method in the treatment of severe PNI through the use of SCs and axon guidance channels.