Prevention of Capsular Contracture with Photochemical Tissue Passivation:

Photosealed Neurorrhaphy Using Autologous Tissue

Photochemical sealing of a nerve wrap over the repair site isolates and optimizes the regenerating nerve microenvironment. To facilitate clinical adoption of the technology, we investigated photosealed autologous tissue in a rodent sciatic nerve transection and repair model. Rats underwent transection of the sciatic nerve with repair performed in three groups: standard microsurgical neurorrhaphy (SN) and photochemical sealing with a crosslinked human amnion (xHAM) or autologous vein. Functional recovery was assessed at four-week intervals using footprint analysis. Gastrocnemius muscle mass preservation, histology, and nerve histomorphometry were evaluated at 120 days. Nerves treated with a PTB-sealed autologous vein improved functional recovery at 120 days although the comparison between groups was not significantly different (SN: -58.4 +/- 10.9; XHAM: -57.9 +/- 8.7; Vein: -52.4 +/- 17.1). Good muscle mass preservation was observed in all groups, with no statistical differences between groups (SN: 69 +/- 7%; XHAM: 70 +/- 7%; Vein: 70 +/- 7%). Histomorphometry showed good axonal regeneration in all repair techniques. These results demonstrate that peripheral nerve repair using photosealed autologous veins produced regeneration at least equivalent to current gold-standard microsurgery. The use of autologous veins removes costs and foreign body concerns and would be readily available during surgery. This study illustrates a new repair method that could restore normal endoneurial homeostasis with minimal trauma following severe nerve injury.

Efficacy of the Modified 5-Item Frailty Index in Predicting Surgical-Site Infections in Patients Undergoing Breast Implant Augmentation: A National Surgical Quality Improvement Project-Based 5-Year Study

Background

The ability to predict breast implant augmentation complications can significantly inform patient management. A frailty measure, such as the modified 5-item frailty index (mFI-5), is becoming an increasingly established risk factor for adverse postoperative outcomes. The authors hypothesized that the mFI-5 is predictive of 30-day postoperative complications in breast augmentation.

Objectives

To investigate if mFI-5 can predict the likelihood and magnitude of 30-day complications resulting from breast augmentations.

Methods

A retrospective review study of the National Surgical Quality Improvement Program database for patients who underwent breast implant augmentation without other concurrent procedures, from 2015 to 2019. Age, BMI, number of major comorbidities, American Society of Anesthesiologists (ASA) classifications, smoking status, mFI-5 score, and modified Charlson comorbidity index score were compared as predictors of all-cause 30-day complications and 30-day surgical-site complications using regression analyses.

Results

Overall, 2478 patients were analyzed, and among them, 53 patients developed complications (2.14%). mFI-5 score significantly predicted surgical-site infection (SSI) complications (odds ratio [OR] = 4.24, P = .026). Frail patients had a higher occurrence of SSIs than nonfrail patients (P = .049). Multivariable analyses showed ASA class predicted 30-day SSI complications (OR = 5.77, P = .027) and mFI-5 approached, but did not reach full significance in predicting overall 30-day complications (OR = 3.14, P = .085).

Conclusions

To date, the impact of frailty on breast implant procedure outcomes has not been studied. Our analysis demonstrates that the mFI-5 is a significant predictor for SSIs in breast implant augmentation surgery and is associated with overall complications. By preoperatively identifying frail patients, the surgical team can better account for postoperative support to minimize the risk of complications.

Level of Evidence 4

Biological Cover Mitigates Disruption of the Dermal Structure in Mechanically Expanded Skin in a Porcine Model

Tissue expansion is an integral procedure of the vast majority of breast reconstruction and has a significant impact on the final clinical outcomes. Therefore, technological advances leading to a fewer number of unfavorable outcomes and a decrease in complication rates are imperative. In this study, using a porcine model, we investigated an effect of acellular dermal matrix (ADM) used as a tissue expander cover on the dermal changes induced by mechanical forces during tissue expansion. After 14 days of expansion, skin samples were collected from one animal, while the second animal underwent radiation, and tissue was collected 8 weeks later. Tissue expanded without the use of ADM and unexpanded skin served as the controls. Collected skin biopsies were used for histological and immunohistochemical evaluation, and for gene expression analysis. We revealed that the biological cover incorporation into host tissue is facilitated by macrophages without inducing a broad inflammatory response. The utilization of ADM mitigated disruption in the dermal structure, excessive collagen deposition, and capsule formation in non-irradiated expanded skin. The protective effect was not fully maintained in irradiated skin. These results demonstrate that tissue expansion might be improved by using the tissue expander cover.

Reduced capsular contracture with smooth and textured breast implants following submuscular mammoplasty: systematic literature review

Background: Capsular contracture is common in breast augmentation and reconstruction surgery. The present systematic review discusses the safety of textured and smooth implants in the submuscular position. Methods: A literature search was conducted on PubMed and EMBASE from inception until June 2020. The primary outcome was reduction of capsular contracture (Baker grade); others included time of capsular contracture onset, implant position/rupture rate/surface, hematoma/seroma risk, surgeon assessment and patient satisfaction. A total of 7731 patients were included from six publications. Results: The overall risk rate for capsular contracture increased from 7.6 to 25% in 10 years. The capsular contracture rates in textured and smooth implants were 3-14% and 6-20%, respectively, and no significant difference between implants was observed when the implants were placed submuscularly. Submuscular placement and textured implants also reduced the incidence of other complications. Conclusion: This systematic review suggests that appropriate placement reduces capsular contracture rate, irrespective of implant surface.

Influence of Rose Bengal Dimerization on Photosensitization

Protein crosslinking photosensitized by rose Bengal (RB^2- ) has multiple medical applications and understanding the photosensitization mechanism can improve treatment effectiveness. To this end, we investigated the photochemical efficiencies of monomeric RB^2- (RB_M ^2- ) and dimeric RB^2- (RB_D ^2- ) and the optimal pH for anaerobic RB^2- photosensitization in cornea. Absorption spectra and dynamic light scattering (DLS) measurements were used to estimate the fractions of RB_M ^2- and RB_D ^2- . RB^2- self-photosensitized bleaching was used to evaluate the photoactivity of RB_M ^2- and RB_D ^2- . The pH dependence of anaerobic RB^2- photosensitization was evaluated in ex vivo rabbit corneas. The 549 nm/515 nm absorption ratio indicated that concentrations > 0.10 mm RB contained RB_D ^2- . Results from DLS gave estimated mean diameters for RB_M ^2- and RB_D ^2- of 0.70 ± 0.02 nm and 1.75 ± 0.13 nm, respectively, and indicated that 1 mm RB^2- contained equal fractions of RB_M ^2- and RB_D ^2- . Quantum yields for RB^2- bleaching were not influenced by RB_D ^2- in RB^2- solutions although accounting for RB^2- concentration effects on the reaction kinetics demonstrated that RB_D ^2- is not a photosensitizer. Optimal anaerobic photosensitization occurred at pH 8.5 for solutions containing 200 mm Arg. These results suggest potential approaches to optimizing RB_M ^2- -photosensitized protein crosslinking in tissues.

The Histological Composition of Capsular Contracture Focussed on the Inner Layer of the Capsule: An Intra-Donor Baker-I Versus Baker-IV Comparison

Background

Capsular contracture remains one of the major complications after breast implantation surgery. The extent of capsular contraction is scored using the Baker scale. The aim of this study was to compare intra-individual Baker-I with Baker-IV capsules, and in particular the prevalence and histological properties of the inner capsule layer.

Methods

Twenty capsules from ten patients were included after bilateral explantation surgery due to unilateral capsular contracture (Baker-IV) after cosmetic augmentation with textured implants. All capsules underwent (immune-)histochemical analysis: haematoxylin–eosin (morphology), CD68 (macrophages), cytokeratin (epithelial cells) and vimentin (fibroblasts), and were visually scored for cell density and the presence of an inner layer and measured for thickness.

Results

Baker-IV (n = 10) capsules were significantly thicker compared to Baker-I (n = 10) capsules (P = 0.004). An inner layer was present in 8 Baker-I capsules. All Baker-I capsules were vimentin and CD68-positive and cytokeratin-negative. Positive vimentin was seen throughout the inner layer, and CD-68 staining was observed adjacent to the intermediate capsule layer. In contrast, only 2 Baker-IV capsules had an inner layer, of which only 1 showed the same profile as Baker-I capsules (P = 0.016). No cytokeratin positivity was seen in any capsule. In Baker-IV capsules, outer layers showed more positivity for both vimentin and CD68.

Conclusion

The inner layer is morphologically consistent with synovial metaplasia and is more prevalent in healthy, uncontracted Baker-I capsules. This inverse relation between the presence of the inner layer and higher Baker classification or pathological contracture could indicate a protective role of the inner layer against capsular contracture formation.

Level of Evidence III

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Rose Bengal Binding to Collagen and Tissue Photobonding

We investigated two critical aspects of rose Bengal (RB) photosensitized protein cross-linking that may underlie recently developed medical applications. Our studies focused on the binding of RB to collagen by physical interaction and the effect of this binding and certain amino acids on RB photochemistry. Molecular dynamics simulations and free-energy calculation techniques, complemented with isothermal titration calorimetry, provided insight into the binding between RB and a collagen-like peptide (CLP) at the atomic level. Electrostatic interactions dominated, which is consistent with the finding that RB bound equally well to triple helical and single chain collagen. The binding free energy ranged from -5.7 to -3 kcal/mol and was strongest near the positively charged amino groups at the N-terminus and on lysine side chains. At high RB concentration, a maximum of 16 ± 3 bound dye molecules per peptide was found, which is consistent with spectroscopic evidence for aggregated RB bound to collagen or the CLP. Within a tissue-mimetic collagen matrix, RB photobleached rapidly, probably due to electron transfer to certain protein amino acids, as was demonstrated in solutions of free RB and arginine. In the presence of arginine and low oxygen concentrations, a product absorbing at 510 nm formed, presumably due to dehalogenation after electron transfer to RB. In the collagen matrix without arginine, the dye generated singlet oxygen as well as the 510 nm product. These results provide the first evidence of the effects of a tissue-like environment on the photochemical mechanisms of rose Bengal.

The Effects of Colchicine-Impregnated Oxidized Regenerated Cellulose on Capsular Contracture

Capsular contracture is the most common complication of breast augmentation. Oxidized regenerated cellulose can be used as a matrix for drug transport. Colchicine is an antimitotic drug that interferes with various steps of wound healing. The aim of this study was to evaluate the effects of oxidized regenerated cellulose alone or in combination with colchicine on capsular contracture. Twenty-one adult female Wistar-Albino rats were divided into 3 groups. In group 1 silicone blocks only, in group 2 oxidized regenerated cellulose-wrapped silicone blocks, and in group 3 colchicine-impregnated oxidized regenerated cellulose-wrapped silicone blocks were inserted in the dorsal region. Four weeks later, implants were removed and histopathological examination was performed. Capsular thickness, inflammatory infiltrate degree, collagen fiber organization, and myofibroblast density were evaluated. Macroscopic examination revealed a distinct capsule formation only in group 1 animals, with average measurement being 134.65 µm on histopathological examination. In groups 2 and 3 animals, no distinct capsule formation was seen. Inflammatory infiltrate degree was found to be less in groups 2 and 3 animals than in group 1 animals. Collagen fiber organization around the implants was found to be parallel and organized in group 1 animals, whereas it was random and disorganized in animals in both groups 2 and 3. High myofibroblast density was observed in animals in groups 1 and 2, while no myofibroblast was found in animals in group 3. The results of our study suggest that coating silicone implants with oxidized regenerated cellulose or with colchicine-impregnated oxidized regenerated cellulose may be effective in preventing capsular contracture.

Role of Mitomycin C in Preventing Capsular Contracture in Implant-Based Reconstructive Breast Surgery: A Randomized Controlled Trial

BACKGROUND

Capsular contracture represents the most frequent complication after implant-based breast reconstruction. An experimental study on mice demonstrated that capsule formation around breast implants is considerably diminished after topical application of mitomycin C. The authors conducted a randomized controlled clinical trial investigating the efficacy of mitomycin C in reducing capsular contracture rates following implant-based breast reconstruction after mastectomy for breast cancer.

METHODS

The authors randomized all women older than 18 years scheduled for the second stage of an implant-based breast reconstruction after mastectomy for breast cancer at the National Cancer Institute in Milan from October of 2005 to February of 2010 to receive or not receive the topical application of mitomycin C during surgery. The authors assessed capsular contracture, major postoperative complications, and aesthetic outcome.

RESULTS

The authors randomized 322 patients to receive mitomycin C or not at the second stage of implant-based breast reconstruction. One hundred sixty-two patients were allocated to the mitomycin C group and 160 patients were allocated to the control group. The relative risk of capsular contracture in the mitomycin C group was 0.92 (95 percent CI, 0.60 to 1.41). Major complications leading to reintervention, oncologic outcomes, and aesthetic outcomes were comparable between the two groups.

CONCLUSIONS

This is the first trial reporting data about the use of mitomycin C in breast reconstructive surgery in a clinical setting. Mitomycin C seems not to significantly affect capsular contracture rate and severity following implant-based reconstructive breast surgery at the tested doses.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

Does Implant Insertion with a Funnel Decrease Capsular Contracture? A Preliminary Report

BACKGROUND

Capsular contracture remains a common and dreaded complication of breast augmentation. The etiology of capsular contracture is believed to be multi-factorial, and its causes may include biofilm formation due to implant/pocket contamination with skin flora. It has been shown that insertion funnel use reduces skin contact and potential contamination by 27-fold in a cadaver model. After incorporating the funnel into our surgical protocols, we anecdotally believed we were experiencing fewer capsular contractures in our augmentation practices.

OBJECTIVES

The purpose of this study was to test the hypothesis that capsular contracture related reoperation rates decreased after insertion funnel adoption using data from multiple practices.

METHODS

At seven participating centers, we retrospectively reviewed the surgical records from March 2006 to December 2012 for female patients who had undergone primary breast augmentation with silicone gel implants. Group 1 consisted of consecutive augmentations done without the insertion funnel, and Group 2 consisted of consecutive augmentations done with the insertion funnel. The primary outcome variable was development of grade III or IV capsular contracture that led to reoperation within 12 months.

RESULTS

A total of 1177 breast augmentations met inclusion criteria for Group 1 and 1620 breast augmentations for Group 2. The rate of reoperation due to capsular contracture was higher without use of the insertion funnel (1.49%), compared to Group 2 with funnel use (0.68%), a 54% reduction (P = 0.004).

CONCLUSIONS

The insertion funnel group experienced a statistically significant reduction in the incidence of reoperations performed due to capsular contracture within 12 months of primary breast augmentation.

Effect of propranolol on capsular reaction around silicone implants in guinea pigs

PURPOSE

To evaluate the effect of propranolol on capsular architecture around silicone implants by measuring the inflammation, capsular thickness, and collagen fiber density, using a guinea pig experimental model.

METHODS

Thirty six adult male guinea pigs randomly divided into two groups (n=18) were used. Each one received a silicone implant with textured-surface. The capsular tissue around implants from untreated or treated animals with the beta-adrenoceptor antagonist propranolol (10 mg/kg, dissolved in daily water) were analyzed for inflammation by histological scoring, capsular thickness by computerized histometry, and collagen fibers type I and Type III density by picrosirius polarization at different time points (7, 14 or 21 days after silicone implantation).

RESULTS

Propranolol treatment reduced inflammation and impaired capsular thickness and delayed collagen maturation around the textured implant.

CONCLUSION

Propranolol reduces the risk of developing capsular contracture around silicone implants with textured surface.