Objective: To analyze the anatomy and sensory outcomes of targeted nipple-areola complex reinnervation (TNR) in gender-affirming double incision mastectomy with free nipple grafting. Background: TNR is a novel technique to preserve and reconstruct intercostal nerves (ICNs) to improve postoperative sensation. There is little evidence of relevant anatomy and outcomes. Methods: Twenty-five patients were prospectively enrolled. Data included demographics, surgical technique, and axon/fascicle counts. Quantitative sensory evaluation using monofilaments and qualitative patient-reported questionnaires was completed preoperatively, and at 1, 3, 6, 9, and 12 months postoperatively. Results: Fifty mastectomies were performed. Per mastectomy, the median number of ICN found and used was 2 (1–5). Axon and fascicle counts were not significantly different between ICN branches (P > 0.05). Body Mass Index ≥30 kg/m² and mastectomy weight ≥800 g were associated with significantly worse preoperative sensation (P < 0.05). Compared with preoperative values, nipple-areola complex (NAC) sensation was worse at 1 month (P < 0.01), comparable at 3 months (P > 0.05), and significantly better at 12 months (P < 0.05) postoperatively. Chest sensation was comparable to the preoperative measurements at 1 and 3 months (P > 0.05), and significantly better at 12 months (P < 0.05) postoperatively. NAC sensation was significantly better when direct coaptation was performed compared with the use of allograft only (P < 0.05), and with direct coaptation of ≥2 branches compared with direct coaptation of a single branch (P < 0.05). All patients reported a return of nipple and chest sensation at 1 year postoperatively and 88% reported a return of some degree of erogenous sensation. Conclusions: TNR allows for restoration of NAC and chest sensation within 3 months postoperatively. The use of multiple ICN branches and direct coaptation led to the best sensory outcomes.

Background Photochemical tissue bonding (PTB) is a technique for peripheral nerve repair in which a collagenous membrane is bonded around approximated nerve ends. Studies using PTB with cryopreserved human amnion have shown promising results in a rat sciatic nerve transection model including a more rapid and complete return of function, larger axon size, and thicker myelination than suture repair. Commercial collagen membranes, such as dehydrated amnion allograft, are readily available, offer ease of storage, and have no risk of disease transmission or tissue rejection. However, the biomechanical properties of these membranes using PTB are currently unknown in comparison to PTB of cryopreserved human amnion and suture neurorrhaphy. Methods Rat sciatic nerves (n = 10 per group) were transected and repaired using either suture neurorrhaphy or PTB with one of the following membranes: cryopreserved human amnion, monolayer human amnion allograft (crosslinked and noncrosslinked), trilayer human amnion/chorion allograft (crosslinked and noncrosslinked), or swine submucosa. Repaired nerves were subjected to mechanical testing. Results During ultimate stress testing, the repair groups that withstood the greatest strain increases were suture neurorrhaphy (69 ± 14%), PTB with crosslinked trilayer amnion (52 ± 10%), and PTB with cryopreserved human amnion (46 ± 20%), although the differences between these groups were not statistically significant. Neurorrhaphy repairs had a maximum load (0.98 ± 0.30 N) significantly greater than all other repair groups except for noncrosslinked trilayer amnion (0.51 ± 0.27 N). During fatigue testing, all samples repaired with suture, or PTBs with either crosslinked or noncrosslinked trilayer amnion were able to withstand strain increases of at least 50%. Conclusion PTB repairs with commercial noncrosslinked amnion allograft membranes can withstand physiological strain and have comparable performance to repairs with human amnion, which has demonstrated efficacy in vivo. These results indicate the need for further testing of these membranes using in vivo animal model repairs.

The objective of the study was to investigate the association between obesity and the presence of secondary surgery following neurolysis, direct nerve repair, or nerve grafting in patients with traumatic brachial plexus injury. In this retrospective chart review spanning two Level I medical centers in a single metropolitan area, 57 patients who underwent neurolysis, direct nerve repair, or nerve grafting for brachial plexus injuries between 2002 and 2015 were identified. Risk regression analysis was used to evaluate the association between obesity status and secondary surgery. After controlling for the confounding variables of age, high energy injury, associated shoulder dislocation and associated clavicle fracture using multivariate regression (risk regression), the risk ratio of secondary surgery in obese patients compared to non-obese patients was 6.99 (P = 0.028). The most common secondary surgery was tendon or local muscle transfer. There is an increased risk of secondary surgery in obese patients compared to non-obese patients of the same age and with the same severity of injury. The increased risk may be due to challenges related to powering a heavier upper extremity. A weight reduction program might be considered as part of the preoperative strategy.

Background: Nerve xenografts harvested from transgenic α1,3-galactosyltransferase knockout pigs lack the epitope responsible for hyperacute rejection in pig-to-primate transplants. It is unknown whether these cold-preserved nerve grafts support axonal regeneration in another species during and after immunosuppression. The authors compared outcomes between autografts and cold-preserved xenografts in a rat sciatic model of nerve gap repair. Methods: Fifty male Lewis rats had a 1-cm sciatic nerve defect repaired using autograft and suture (n = 10); 1-week or 4-week cold-preserved xenograft and suture (n = 10 per group); or 1-week or 4-week cold-preserved xenograft and photochemical tissue bonding using a human amnion wrap (n = 10 per group). Rats with xenografts were given tacrolimus until 4 months postoperatively. At 4 and 7 months, rats were killed and nerve sections were harvested. Monthly sciatic functional index (SFI) scores were calculated. Results: All groups showed increases in SFI scores by 4 and 7 months. The autograft suture group had the highest axon density at 4 and 7 months. The largest decrease in axon density from 4 to 7 months was in the group with 1-week cold-preserved photochemical tissue bonding using a human amnion wrap. The only significant difference between group SFI scores occurred at 5 months, when both 1-week cold-preserved groups had significantly lower scores than the 4-week cold-preserved suture group. Conclusions: The results suggest that α1,3-galactosyltransferase knockout nerve xenografts may be viable alternatives to autografts. Further studies of long-gap repair and comparison with acellular nerve allografts are needed. Clinical Relevance Statement: This proof-of-concept study in the rat sciatic model demonstrates that cold-preserved α1,3-galactosyltransferase knockout porcine xenografts support axonal regeneration and viability following immunosuppression withdrawal. These results further suggest a role for both cold preservation and photochemical tissue bonding in modulating the immunological response at the nerve repair site.

Summary: Chronic postoperative pain after breast surgery is a significant concern, with studies indicating varying rates depending on the type of surgical procedure. The risk of developing neuropathic pain is notably increased with axillary lymph node dissection due to potential nerve injuries. Additionally, the method of breast reconstruction may influence postsurgical pain rates, with conflicting findings on the impact of reconstruction type. Recent advancements in techniques such as targeted muscle reinnervation, among others, show promise in addressing postoperative pain in these patients. As the prevalence of these procedures rises, future research is likely to focus on assessing and managing pain in this patient population. The development of patient-reported outcome measures specific to breast surgery pain can aid in clinical assessment and treatment planning. This review emphasizes the importance of gaining a deeper understanding of risk factors, nerve anatomy, and treatment options to enhance outcomes and quality of life for individuals undergoing breast surgery.