Assessing the Impact of Neighborhood and Built Environment on Pediatric Perioperative Care: A Systematic Review of the Literature.

CONTEXT: Neighborhood and built environment encompass one key area of the Social Determinants of Health (SDOH) and is frequently assessed using area-level indices. OBJECTIVE: We sought to systematically review the pediatric surgery literature for use of commonly applied area-level indices and to compare their utility for prediction of outcomes. DATA SOURCES: A literature search was conducted using PubMed, Ovid MEDLINE, Ovid MEDLINE Epub Ahead of Print, PsycInfo, and an artificial intelligence search tool (1/2013-2/2023). STUDY SELECTION: Inclusion required pediatric surgical patients in the US, surgical intervention performed, and use of an area-level metric. DATA EXTRACTION: Extraction domains included study, patient, and procedure characteristics. RESULTS: Area Deprivation Index is the most consistent and commonly accepted index. It is also the most granular, as it uses Census Block Groups. Child Opportunity Index is less granular (Census Tract), but incorporates pediatric-specific predictors of risk. Results with Social Vulnerability Index, Neighborhood Deprivation Index, and Neighborhood Socioeconomic Status were less consistent. LIMITATIONS: All studies were retrospective and quality varied from good to fair. CONCLUSIONS: While each index has strengths and limitations, standardization on ideal metric(s) for the pediatric surgical population will help build the inferential power needed to move from understanding the role of SDOH to building meaningful interventions towards equity in care. TYPE OF STUDY: Systematic Review. LEVEL OF EVIDENCE: Level III.

The Challenge of Small Intestine Length Measurement: A Systematic Review of Imaging Techniques.

BACKGROUND: Short bowel syndrome is the most common cause of intestinal failure, with morbidity and mortality linked to remanent small intestine length. There is no current standard for noninvasive bowel length measurement. MATERIALS AND METHODS: The literature was systematically searched for articles describing measurements of small intestine length from radiographic studies. Inclusion required reporting intestinal length as an outcome and use of diagnostic imaging for length assessment compared to a ground truth. Two reviewers independently screened studies for inclusion, extracted data, and assessed study quality. RESULTS: Eleven studies met the inclusion criteria and reported small intestinal length measurement using four imaging modalities: barium follow-through, ultrasound, computed tomography, and magnetic resonance. Five barium follow-through studies reported variable correlations with intraoperative measurements (r = 0.43-0.93); most (3/5) reported underestimation of length. US studies (n = 2) did not correlate with ground truths. Two computed tomography studies reported moderate-to-strong correlations with pathologic (r = 0.76) and intraoperative measurements (r = 0.99). Five studies of magnetic resonance showed moderate-to-strong correlations with intraoperative or postmortem measurements (r = 0.70-0.90). Vascular imaging software was used in two studies, and a segmentation algorithm was used for measurements in one. CONCLUSIONS: Noninvasive measurement of small intestine length is challenging. Three-dimensional imaging modalities reduce the risk of length underestimation, which is common with two-dimensional techniques. However, they also require longer times to perform length measurements. Automated segmentation has been trialed for magnetic resonance enterography, but this method does not translate directly to standard diagnostic imaging. While three-dimensional images are most accurate for length measurement, they are limited in their ability to measure intestinal dysmotility, which is an important functional measure in patients with intestinal failure. Future work should validate automated segmentation and measurement software using standard diagnostic imaging protocols.

Axonal Regeneration Through Autologous Grafts: Does the Axonal Load Influence Regeneration?

INTRODUCTION: Two-stage free functional muscle transfers for long-standing facial palsy can yield unpredictable results. Earlier studies have demonstrated incomplete regeneration across neurorrhaphies in native nerve and higher donor axonal counts correlating with improved outcomes but axonal count in nerve grafts have not been as thoroughly reviewed. To investigate the impact of varying axonal counts in autologous grafts on functional outcomes of repair. MATERIALS AND METHODS: Animals were allocated into three groups: Direct Nerve Repair (DNR, n = 50), Small Nerve Graft (SNG, n = 50), and Large Nerve Graft (LNG, n = 50). All grafts were inset into the Posterior Auricular Nerve with ear movement recovery (EMR) monitored as functional outcome. At various postoperative weeks (POWs), excised specimens were imaged with electron microscopy. Axonal counts were measured proximal to, distal (DAC) to, and within grafts. Total Success Ratio (TSR) was calculated. RESULTS: In DNR, DAC was significantly lower than proximal axonal counts at all POWs, with maximum TSR of 80%. TSR for LNG and SNG were significantly lower at all POWs when compared to DNR, with maximums of 56% and 38%, respectively. LNG had a significantly larger DAC than SNG at POW12 and beyond. A direct relationship was present between DAC and EMR for all values. CONCLUSIONS: Higher native axonal count of autologous nerve grafts resulted in higher percentage of regeneration across neurorrhaphies.

Central versus peripheral nervous system regeneration: is there an exception for cranial nerves?

There exists a dichotomy in regenerative capacity between the PNS and CNS, which poses the question - where do cranial nerves fall? Through the discussion of the various cells and processes involved in axonal regeneration, we will evaluate whether the assumption that cranial nerve regeneration is analogous to peripheral nerve regeneration is valid. It is evident from this review that much remains to be clarified regarding both PNS and CNS regeneration. Furthermore, it is not clear if cranial nerves follow the PNS model, CNS model or possess an alternative novel regenerative process altogether. Future research should continue to focus on elucidating how cranial nerves regenerate; and the various cellular interactions, molecules and pathways involved.

Pretest and Posttest Evaluation of a Longitudinal, Residency-Integrated Microsurgery Course.

INTRODUCTION: Current microsurgical training courses average 5 consecutive 8-hour days and cost US $1500 to US $2500/individual, making training a challenge for residents who are unable to take leave from clinical duties. This residency-integrated microsurgery course was designed for integration with a residency program, averaging 3 hours/week over 7 weeks. This allows for one-on-one training, beginning with synthetic tissue and concluding with in vivo stimulation. This study was performed to validate this longitudinal training course. METHODS: After recruitment and before the start of coursework, subjects completed a baseline anastomosis without guidance and a survey regarding microsurgical experience. Subjects completed approximately 3 hours/week of practical exercises. Weeks 1 to 5 used synthetic models, whereas 6 to 7 used in vivo rodent models. Nine minimum anastomoses of increasing complexity were completed and assessed with the Anastomosis Lapse Index and the Stanford Microsurgery and Residency Training scale. Scoring was performed by 3 independent reviewers and averaged for comparison. RESULTS: Five subjects completed the course for study. Presurvey results showed an average confidence in theoretical knowledge of 2/5; technical ability to perform procedures, 1.8/5; and ability to manage complications, 1.8/5. Postsurvey revealed confidence in theoretical knowledge of 2.5/5; technical ability to perform procedures, 2.25/5; and ability to manage complications, 2.25/5. None of these differences were significant. Each individual component of the Stanford Microsurgery and Residency Training scale scoring system improved postcourse with P < 0.05, and overall performance score improved from an average of 2.6 to 3.9 (P = 0.006). The total number of errors recorded using the Anastomosis Lapse Index reduced from 6.58 to 3.41 (P = 0.02). Time to completion reduced from an average of 28 minutes, 8 seconds to 24 minutes, 5 seconds (P = 0.003). CONCLUSIONS: Despite a lack in significant confidence improvement, completion of the residency-integrated microsurgery course leads to significant and quantifiable improvement in resident microsurgical skill and efficiency.

Outcome measures of facial nerve regeneration: A review of murine model systems.

Animal models of nerve function have been subject to extensive study in order to understand and investigate methods which may improve axon regeneration and promote functional outcomes following nerve injury and repair. As the facial nerve is a cranial nerve, there is mounting evidence that cranial nerve regeneration differs from peripheral, and outcome models specifically addressing the facial nerve are required. Murine models are the most commonly utilized, with a variety of methods employed to measure the actions of whisking, eye closure, or ear movement as indicators of facial nerve regeneration. Each method of measurement is reviewed in terms of validity, strengths, limitations, and the specific outcome data provided. The authors propose that prior to choosing an outcome model, the goals and objectives of a planned study should be well defined, as various outcome measures may be useful depending on the information which is desired. The aim of this paper, therefore, is to provide the reader with a concise review which may facilitate project design.

Thin and Ultra-Thin Split-Thickness Skin Grafts Are Safe and Efficacious in the Burn Population.

Split-thickness skin-grafts are a mainstay of burn management. Studies suggest no benefit to using thick (0.025 inch) over standard (0.012-0.020 inch) grafts, and some support the use of thin (0.008 inch) over standard thickness. Data on the use of even thinner grafts is scarce. This study reviewed outcomes of burn patients treated with thin (0.008-0.011 inch) and ultra-thin (≤0.007 inch) grafts. Retrospective review of records from July 2012 to June 2016 included patients who sustained operative burns treated by a single surgeon. Patients were excluded for nonoperative injuries, inhalational injuries, or prolonged hospitalizations. Outcome measures were compared between thin and ultra-thin groups. One-hundred twenty-eight patients met inclusion criteria; 35 received thin split-thickness skin-grafts while 93 received ultra-thin. Cohort analysis demonstrated equivalent graft-take, time to reepithelialization, and functional outcomes. Time to donor-site healing was significantly faster in the ultra-thin cohort (P = .04). Of those with functional outcomes recorded, 88.1% had good-excellent function and 11.9% retained a limitation in function as designated in physical therapy notes. There were fewer complications overall (P = .004) and a lower incidence of hypertrophic scarring (P = .025) in the ultra-thin cohort. This study presents a single-surgeon experience with thin and ultra-thin split-thickness skin-grafts. These grafts are exhibit excellent graft-take and few complications. There was no correlation between thickness and functional outcome at the time of physical therapy discharge. Donor-site reepithelialization was faster with ultra-thin grafts, which may be important in patients with large burns and limited donor sites.

Imaging Peripheral Nerve Regeneration: A New Technique for 3D Visualization of Axonal Behavior.

BACKGROUND: Peripheral nerve assessment has traditionally been studied through histological and immunological staining techniques in a limited cross-sectional modality, making detailed analysis difficult. A new application of serial section electron microscopy is presented to overcome these limitations. METHODS: Direct nerve repairs were performed on the posterior auricular nerve of transgenic YFP-H mice. Six weeks postoperatively the nerves were imaged using confocal fluorescent microscopy then excised and embedded in resin. Resin blocks were sequentially sectioned at 100 nm, and sections were serially imaged with an electron microscope. Images were aligned and autosegmented to allow for 3D reconstruction. RESULTS: Basic morphometry and axonal counts were fully automated. Using full 3D reconstructions, the relationships between the axons, the Nodes of Ranvier, and Schwann cells could be fully appreciated. Interactions of individual axons with their surrounding environment could be visualized and explored in a virtual three-dimensional space. CONCLUSIONS: Serial section electron microscopy allows the detailed pathway of the regenerating axon to be visualized in a 3D virtual space in comparison to isolated individual traditional histological techniques. Fully automated histo-morphometry can now give accurate axonal counts, provide information regarding the quality of nerve regeneration, and reveal the cell-to-cell interaction at a super-resolution scale. It is possible to fully visualize and "fly-through" the nerve to help understand the behavior of a regenerating axon within its environment. This technique provides future opportunities to evaluate the effect different treatment modalities have on the neuroregenerative potential and help us understand the impact different surgical techniques have when treating nerve injuries.

Development of the interscutularis model as an outcome measure for facial nerve surgery.

INTRODUCTION: Animal models for the study of facial paralysis have been well developed, but concern has arisen regarding the accuracy of eye closure and whisker movement as outcome measures due to new data regarding interconnectivity between facial nerve branches and autonomic innervation. The posterior auricular nerve (PAN) is an isolated branch of the facial nerve which has been confirmed as the sole motor innervat or of the interscutularis muscle. This study was designed to develop a model for facial nerve palsy utilizing the PAN and interscutularis muscle. METHODS: A custom-made automated video capture system was built into a poly methyl methacrylate cage using a high definition monochrome digital camera and image sensor to record the animal as it drank from a water feeder. A copper floor pad and copper collar around the water feeder were connected to an electrical circuit for automatic saving of the video recording 10 s prior to and 30 s following the drinking event. A pre-operative baseline recording of ear movement during drinking was captured. Female YFP-16 mice at 6 weeks were assigned to sham (Sh, n = 5), nerve excision (Ex, n = 10), or nerve crush (Cr, n = 10) groups with all interventions performed on the right PAN. Sh mice were irrigated with 10 ml normal saline as were the Ex and Cr mice following operative intervention. In Ex mice, a 3 mm section of the PAN was sharply excised and nerve gap was confirmed with fluorescent microscopy. In Cr mice, the PAN was crushed 3 mm from the origin of the facial nerve trunk with size 5 jeweler's forceps for two periods of 20 s. Post-operative video recordings were collected on post-operative days (POD) 1, 10, 20, and 30. To determine the change in ear movement, the right ear was graphically compared to the left control side. RESULTS: Sh animals exhibited a statistically significant reduction in ear movement at POD01 compared to other POD recordings (p < 0.05), but no significant change in right ear movement following POD05. Ex animals had a significant reduction in right ear movement at all PODs in comparison to the left ear (p < 0.05) with no significant change in right ear movement during the study period (p = 0.94). Cr animals showed a significant reduction in right ear movement compared to the left at POD01, POD10, and POD20 (p < 0.05). At POD30, there was no significant difference between ear movement on either side (p = 0.35). There was a significant change in right ear movement during the data collection period (p < 0.05). CONCLUSION: The results show that significant differences were demonstrated between the experimental groups and that significant changes within the crush group were identifiable making this an acceptable model to develop as an accurate outcome measure following rodent facial nerve surgery.

Oral omega-3 fatty acids promote resolution in chemical peritonitis.

BACKGROUND: Recent studies suggest that purified omega-3 fatty acids may attenuate acute inflammation and hasten the transition to healing. In this study, we tested the hypothesis that pretreatment with omega-3-rich fish oil (FO) would promote resolution of peritoneal inflammation through production of specific lipid mediators. METHODS: C57/BL6 mice were given a daily 200-µL oral gavage of saline (CTL) or FO (1.0-1.5 g/kg/d docosahexaenoic acid and 1.3-2.0 g/kg/d eicosapentaenoic acid) for 7 d before chemical peritonitis was induced with thioglycollate. Peritoneal lavage fluid was collected before induction and at days 2 and 4 after peritonitis onset. Prostaglandin E2 (PGE2), Leukotriene B4 (LTB4), Resolvin D1 (RvD1), and the composition of immune cell populations were examined in peritoneal lavage exudates. Cells harvested from the peritoneum were assessed for macrophage differentiation markers, phagocytosis, and lipopolysaccharide-induced cytokine secretion profiles (interleukin [IL]-6, IL-10, IL-1ß, TNFα). RESULTS: The ratio of RvD1 to pro-inflammatory PGE2 and LTB4 was increased in the peritoneal cavity of FO-supplemented animals. FO induced a decrease in the number of monocytes in the lavage fluid, with no change in the number of macrophages, neutrophils, or lymphocytes. Macrophage phagocytosis and M1/M2 messenger RNA markers were unchanged by FO with the exception of decreased PPARγ expression. FO increased ex vivo TNFα secretion after stimulation with lipopolysaccharide. CONCLUSIONS: Our findings provide evidence that nutraceutically relevant doses of FO supplements given before and during chemical peritonitis shift the balance of lipid mediators towards a proresolution, anti-inflammatory state without drastically altering the number or phenotype of local innate immune cell populations.