Efficacy of antiadhesion barrier solution on periimplant capsule formation in a white rat model

Reducing Peri-implant Capsule Thickness in Submuscular Rodent Model of Breast Reconstruction With Delayed Radiotherapy

INTRODUCTION

Capsular contracture remains the most common complication following device-based breast reconstruction, occurring in up to 50% of women who also undergo adjuvant radiotherapy either before or after device-based reconstruction. While certain risk factors for capsular contracture have been identified, there remains no clinically effective method of prevention. The purpose of the present study is to determine the effect of coating the implant with the novel small molecule Met-Z2-Y12, with and without delayed, targeted radiotherapy, on capsule thickness and morphologic change around smooth silicone implants placed under the latissimus dorsi in a rodent model.

METHODS

Twenty-four female Sprague Dawley rats each had 2 mL smooth round silicone breast implants implanted bilaterally under the latissimus dorsi muscle. Twelve received uncoated implants and twelve received implants coated with Met-Z2-Y12. Half of the animals from each group received targeted radiotherapy (20 Gray) on postoperative day ten. At three and 6 months after implantation, the tissue surrounding the implants was harvested for analysis of capsular histology including capsule thickness. Additionally, microCT scans were qualitatively analyzed for morphologic change.

RESULTS

Capsules surrounding Met-Z2-Y12-coated implants were significantly thinner (P = 0.006). The greatest difference in capsule thickness was seen in the irradiated 6-month groups, where mean capsule thickness was 79.1 ± 27.3 μm for uncoated versus 50.9 ± 9.6 μm for Met-Z2-Y12-coated implants (P = 0.038). At the time of explant, there were no capsular morphologic differences between the groups either grossly or per microCT.

CONCLUSIONS

Met-Z2-Y12 coating of smooth silicone breast implants significantly reduces capsule thickness in a rodent model of submuscular breast reconstruction with delayed radiotherapy.

The effects of human amniotic membrane on silicone related capsule formation in rats

Silicone breast implants are commonly used materials in plastic surgery for breast augmentation and reconstruction and the most severe complication of silicone implants are capsule contraction which occurs in 40% of patients. The aim of our study is to evaluate how the amniotic membrane alters the capsule formation effects of silicone 24 wistar rats were used in the study. We placed a bare silicone block into the left side (Subgroup A) and single layer amniotic membrane coated silicone block into the right side (Subgroup B) of the rats back. The rats were then separated into three groups and in group 1 rats were euthanized after 3 weeks, in group 2 after 12 weeks and in group 3 after 24 weeks. Then capsule thickness, fibroblast and lymphocyte cell counts were evaluated for each sample. In Group 2 and group 3, the capsule thickness in Subgroup B was detected to be statistically significantly lower than that in Subgroup A. In Group 1, 2, and 3, the lymphocyte count in the capsule tissue taken from Subgroup B was lower than Subgroup A but the difference was not statistically significant. In Group 2 and 3, the fibrocyte count detected in the capsule tissue in Subgroup B was found to be statistically significantly lower than Subgroup A. the amniotic membrane was demonstrated to reduce capsule thickness by the antifibrinolytic effect in our study.

Effects of an antiadhesive agent on functional recovery of the greater auricular nerve after parotidectomy: a double-blind randomized controlled trial

PURPOSE

Periauricular sensory deficit occurs frequently after parotidectomy even in cases with preservation of the greater auricular nerve (GAN). This study was performed to evaluate the effects of antiadhesive agent in functional recovery of the GAN after parotidectomy.

METHODS

Ninety-eight patients undergoing partial parotidectomy for benign parotid tumors were prospectively enrolled in this multicenter, double-blind randomized controlled study and randomly assigned to either the study or control group. Antiadhesive agent was applied in the study group. The results of sensory tests (tactile, heat, and cold sensitivity) and a questionnaire on quality of life (QoL) were acquired at postoperative 1, 8, and 24 weeks after surgery. Clinical parameters, and the results of the sensory tests and the questionnaire, were compared between the two groups.

RESULTS

A total of 80 patients were finally enrolled. On sensory evaluation, tactile sensation and warm sensation in the ear lobule, and warm sensation in the mastoid area, showed significant improvement at 24 weeks postoperatively in the study group. There were no significant differences between the two groups on any questions in the QoL questionnaire, at any follow-up time point.

CONCLUSIONS

Antiadhesive agents have some positive effects on functional recovery of the GAN after parotidectomy. Therefore, applying antiadhesive agents after parotidectomy can reduce discomfort in patients.

Silicone breast implant modification review: overcoming capsular contracture

Background

Silicone implants are biomaterials that are frequently used in the medical industry due to their physiological inertness and low toxicity. However, capsular contracture remains a concern in long-term transplantation. To date, several studies have been conducted to overcome this problem. This review summarizes and explores these trends.

Main body

First, we examined the overall foreign body response from initial inflammation to fibrosis capsule formation in detail and introduced various studies to overcome capsular contracture. Secondly, we introduced that the main research approaches are to inhibit fibrosis with anti-inflammatory drugs or antibiotics, to control the topography of the surface of silicone implants, and to administer plasma treatment. Each study examined aspects of the various mechanisms by which capsular contracture could occur, and addressed the effects of inhibiting fibrosis.

Conclusion

This review introduces various silicone surface modification methods to date and examines their limitations. This review will help identify new directions in inhibiting the fibrosis of silicone implants.

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.

The pathology of the foreign body reaction against biomaterials

The healing process after implantation of biomaterials involves the interaction of many contributing factors. Besides their in vivo functionality, biomaterials also require characteristics that allow their integration into the designated tissue without eliciting an overshooting foreign body reaction (FBR). The targeted design of biomaterials with these features, thus, needs understanding of the molecular mechanisms of the FBR. Much effort has been put into research on the interaction of engineered materials and the host tissue. This elucidated many aspects of the five FBR phases, that is protein adsorption, acute inflammation, chronic inflammation, foreign body giant cell formation, and fibrous capsule formation. However, in practice, it is still difficult to predict the response against a newly designed biomaterial purely based on the knowledge of its physical-chemical surface features. This insufficient knowledge leads to a high number of factors potentially influencing the FBR, which have to be analyzed in complex animal experiments including appropriate data-based sample sizes. This review is focused on the current knowledge on the general mechanisms of the FBR against biomaterials and the influence of biomaterial surface topography and chemical and physical features on the quality and quantity of the reaction. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 927-940, 2017.

Effects of Medical Chitosan on Capsular Formation Following Silicone Implant Insertion in a Rabbit Model

BACKGROUND

Capsular contracture is a serious complication that occurs after breast implant surgery. This study was performed to confirm that medical chitosan (MC) affects capsule formation and elucidates a possible mechanism.

MATERIALS AND METHODS

In this study, we used 18 female adult New Zealand White rabbits. In each rabbit, two silicone implants were placed under the pectoralis muscle layer on both sides (one side was included in the experimental group and the other side was included in the control group). MC was applied around the silicone implant of the experiment group, while the control group received no treatment. The capsular thickness was calculated by Masson's trichrome stain. The expression of MMPs and TIMPs were determined by real-time PCR, Western blotting, and immunohistochemistry.

RESULTS

Compared to the control group, the capsular thickness of the MC group was significantly reduced at 4, 8, and 12 weeks after the operation (4 week: 229.3 ± 72.2 vs 76.1 ± 12.6 µm, p < 0.05; 8 week: 326.0 ± 53.8 vs 155.4 ± 61.7 µm, p < 0.0.5; 12 week: 151.2 ± 52.5 vs 60.0 ± 22.0 µm, p < 0.05). Compared to the control group, the MC group had significantly lower expressions of TIMP-1 and TIMP-2 (p < 0.05). However, compared to the control group, there was no statistically significant difference in the expressions of MMP-2 and MMP-9 in the experiment group (p > 0.05).

CONCLUSION

MC reduced the risk of developing capsular contracture around silicone implants, possibly by blocking the signaling pathway of TIMPs.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266.

Capsular Contracture after Breast Augmentation: An Update for Clinical Practice

Capsular contracture is the most common complication following implant based breast surgery and is one of the most common reasons for reoperation. Therefore, it is important to try and understand why this happens, and what can be done to reduce its incidence. A literature search using the MEDLINE database was conducted including search terms 'capsular contracture breast augmentation', 'capsular contracture pathogenesis', 'capsular contracture incidence', and 'capsular contracture management', which yielded 82 results which met inclusion criteria. Capsular contracture is caused by an excessive fibrotic reaction to a foreign body (the implant) and has an overall incidence of 10.6%. Risk factors that were identified included the use of smooth (vs. textured) implants, a subglandular (vs. submuscular) placement, use of a silicone (vs. saline) filled implant and previous radiotherapy to the breast. The standard management of capsular contracture is surgical via a capsulectomy or capsulotomy. Medical treatment using the off-label leukotriene receptor antagonist Zafirlukast has been reported to reduce severity and help prevent capsular contracture from forming, as has the use of acellular dermal matrices, botox and neopocket formation. However, nearly all therapeutic approaches are associated with a significant rate of recurrence. Capsular contracture is a multifactorial fibrotic process the precise cause of which is still unknown. The incidence of contracture developing is lower with the use of textured implants, submuscular placement and the use of polyurethane coated implants. Symptomatic capsular contracture is usually managed surgically, however recent research has focussed on preventing capsular contracture from occurring, or treating it with autologous fat transfer.

Understanding the Etiology and Prevention of Capsular Contracture: Translating Science into Practice

Capsular contracture remains a common and preventable complication of implanted breast prostheses. As our understanding of the pathophysiology continues to develop, it is prudent to reexamine existing beliefs in a contemporary context. This article presents a current summary of clinical and laboratory evidence, expressed as an interaction between potentiating and suppressing factors, and how this understanding can be applied to practice.

Biomedical implant capsule formation: lessons learned and the road ahead

Clinicians and investigators have been implanting biomedical devices into patients and experimental animals for centuries. There is a characteristic complex inflammatory response to the presence of the biomedical device with diverse cell signaling, followed by migration of fibroblasts to the implant surface and the eventual walling off of the implant in a collagen capsule. If the device is to interact with the surrounding tissues, the collagen envelope will eventually incapacitate the device or myofibroblasts can cause capsular contracture with resulting distortion, migration, or firmness. This review analyzes the various tactics used in the past to modify or control capsule formation with suggestions for future investigative approaches.

Effect of Antiadhesion Barrier Solution and Fibrin on Capsular Formation After Silicone Implant Insertion in a White Rat Model

INTRODUCTION

One of the most serious complications of breast reconstruction and augmentation using silicone implants is capsular contracture. Several preventive treatments, including vitamin E, steroids, antibiotics, and cysteinyl leukotriene inhibitors, have been studied, and their clinical effects have been reported. However, the problem of capsular contracture has not yet been completely resolved. This study was performed to compare anti-adhesion barrier solution (AABS) and fibrin in their ability to prevent fibrotic capsule formation and simultaneously evaluated their effect when used in combination by capsular thickness analysis and quantitative analysis of matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and type I collagen within the fibrous capsule.

MATERIALS AND METHODS

This study used female six-week-old Sprague-Dawley rats. Eighty rats were equally subdivided into the four following groups: AABS-treated, fibrin-treated, AABS and fibrin combined-treated, and untreated control groups. Each rat received two silicone chips under the panniculus carnosus muscle layer. The test materials were applied around the silicon chips. Four weeks later, the implantation sites including the skin and muscle were excised to avoid the risk of losing the fibrous capsule around the implants. The capsular thickness was analyzed by Masson's trichrome stain. Quantitative analysis of type I collagen, MMPs, and TIMPs was performed by real-time PCR, Western blot, and zymography.

RESULTS

The mean capsular thickness was 668.10 ± 275.12 μm in the control group, 356.97 ± 112.11 μm in the AABS-treated group, 525.96 ± 130.97 μm in the fibrin-treated group, and 389.24 ± 130.51 μm in the AABS and fibrin combined-treated group. Capsular thickness was significantly decreased in all experimental groups (p < 0.05). Capsular thickness was greater in the fibrin-treated group than in the AABS-treated group (p < 0.05). There was no statistically significant difference in capsular thickness between the AABS and fibrin combined-treated group and the AABS- or fibrin-treated group (p > 0.05). Compared to the control group, the experimental groups had significantly lower expressions of type I collagen and MMP-1 (p < 0.05), but there was no statistically significant difference in expressions of type I collagen and MMP-1 between the AABS-, fibrin-, and AABS and fibrin combined-treated groups (p > 0.05). The expressions of MMP-2 and TIMP-2 were not significantly different between the control and the experimental groups (p > 0.05).

CONCLUSION

AABS is more effective in reducing capsular thickness compared with fibrin treatment in a white rat model.

Pulsed acoustic cellular expression (PACE) reduces capsule formation around silicone implants

Capsular contracture remains a major complication after reconstructive or aesthetic breast augmentation. Formation of capsular fibrosis is a multifactorial process. An initial inflammatory reaction appears to be key to the development of capsular contracture. Recent studies have shown that pulsed acoustic cellular expression (PACE) has significant antiinflammatory effects. Thus, this study aimed to determine the potential of PACE to prevent or attenuate capsular contracture around silicone implants in a rodent model. For this study, 36 Lewis rats were divided into two groups, and a textured silicone implant was placed in a dorsal submuscular pocket. One group received PACE treatment, whereas the other group served as the control group and received no treatment. Follow-up evaluations were performed after 10, 35, and 100 days. Capsule thickness, collagen density, myofibroblasts, vascular density, and a semiquantitative real-time polymerase chain reaction that addressed differential gene expression were assessed. The PACE treatment significantly reduced capsule thickness on days 10, 35, and 100 compared with the control group (day 10: 632.9 ± 164.5 vs 932.6 ± 160.8, p < 0.05; day 35: 709.5 ± 175 vs 825.9 ± 313.3, p < 0.0.5; day 100: 736.3 ± 198.1 vs 1,062.3 ± 151.9, p < 0.05). This was accompanied by a significant suppression of proinflammatory genes (cluster of differentiation 68, monocyte chemotactic protein-1, CCL4) and synergistic alterations of pro- and antifibrotic proteins (transforming growth factor-beta 1, matrix metalloproteinase-2). This study showed that the PACE application significantly reduces capsular contracture around silicone implants. A decrease in capsular thickness after PACE treatment seems to be associated with a downregulation of proinflammatory genes and proteins. The study identifies PACE technology as a potential low-cost technique that is easy to use for reduction of capsular contracture after augmentation using silicone implants.

NO LEVEL ASSIGNED

This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors http://www.springer.com/00266 .

Prevention of capsular contracture with Guardix-SG(®) after silicone implant insertion

BACKGROUND

Capsular contracture is the most common side effect of breast implant insertion and the problem that breast surgeons seek to avoid the most. Previous animal studies have proved that an antiadhesive barrier solution (AABS) prevents peri-implant capsule formation. In this study, the authors sought to explore the effect that Guardix-SG(®), an AABS that can encapsulate implants in the form of a gel, can have on capsular contracture.

METHOD

This study used 12 female New Zealand white rabbits weighing 2.5-3 kg. Implants were inserted into the subpanniculus carnosus plane through an incision in the bilateral midback area. Once the implant was inserted, 3 g of Guardix-SG(®) and normal saline were instilled into the left and right sides, respectively. The rabbits were killed 6 months after the procedure. The intracapsular pressure was measured using tonometry with a 38.2-g circular glass piece, and capsular thickness was measured by dyeing the biopsy specimen with hematoxylin and eosin and Masson's trichrome stain. The myofibroblasts were quantitatively analyzed through monoclonal anti-alpha smooth muscle actin antibody immunohistochemistry staining.

RESULTS

The intracapsular pressure in the control group (4.51 ± 0.98 mmHg) was significantly higher (p = 0.002) than in the study group (3.51 ± 0.4 mmHg). The average capsular thickness was significantly greater in the control group (0.33 ± 0.15 mm; p = 0.015). In the analysis, the interrelation between capsular thickness and intracapsular pressure was insignificant in both groups, as was the number of myofibroblasts in both groups (p = 0.582).

CONCLUSION

Through this study, the authors were able to demonstrate that capsular contracture can be suppressed in the rabbit model by instilling Guardix-SG(®) after insertion of cohesive gel implants in the subpanniculus carnosus plane.

LEVEL OF EVIDENCE IV

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

How smart do biomaterials need to be? A translational science and clinical point of view

Over the last 4 decades innovations in biomaterials and medical technology have had a sustainable impact on the development of biopolymers, titanium/stainless steel and ceramics utilized in medical devices and implants. This progress was primarily driven by issues of biocompatibility and demands for enhanced mechanical performance of permanent and non-permanent implants as well as medical devices and artificial organs. In the 21st century, the biomaterials community aims to develop advanced medical devices and implants, to establish techniques to meet these requirements, and to facilitate the treatment of older as well as younger patient cohorts. The major advances in the last 10 years from a cellular and molecular knowledge point of view provided the scientific foundation for the development of third-generation biomaterials. With the introduction of new concepts in molecular biology in the 2000s and specifically advances in genomics and proteomics, a differentiated understanding of biocompatibility slowly evolved. These cell biological discoveries significantly affected the way of biomaterials design and use. At the same time both clinical demands and patient expectations continued to grow. Therefore, the development of cutting-edge treatment strategies that alleviate or at least delay the need of implants could open up new vistas. This represents the main challenge for the biomaterials community in the 21st century. As a result, the present decade has seen the emergence of the fourth generation of biomaterials, the so-called smart or biomimetic materials. A key challenge in designing smart biomaterials is to capture the degree of complexity needed to mimic the extracellular matrix (ECM) of natural tissue. We are still a long way from recreating the molecular architecture of the ECM one to one and the dynamic mechanisms by which information is revealed in the ECM proteins in response to challenges within the host environment. This special issue on smart biomaterials lists a large number of excellent review articles which core is to present and discuss the basic sciences on the topic of smart biomaterials. On the other hand, the purpose of our review is to assess state of the art and future perspectives of the so called "smart biomaterials" from a translational science and specifically clinical point of view. Our aim is to filter out and discuss which biomedical advances and innovations help us to achieve the objective to translate smart biomaterials from bench to bedside. The authors predict that analyzing the field of smart biomaterials from a clinical point of view, looking back 50 years from now, it will show that this is our heritage in the 21st century.

Effect of a mixed solution of sodium hyaluronate and carboxymethyl cellulose on upper limb dysfunction after total mastectomy: a double-blind, randomized clinical trial

Restricted shoulder mobility is a major upper limb dysfunction related to lower quality of life and disability after breast cancer surgery. We hypothesized that sodium hyaluronate-carboxymethyl cellulose (HA-CMC) applied to the surface of the pectoralis major muscle after mastectomy would significantly reduce pain and improve range of motion (ROM) of the shoulder in breast cancer patients. We conducted a double-blind, randomized controlled study to evaluate the clinical efficacy and safety of HA-CMC in the prevention of upper limb dysfunction after total mastectomy (TM). A total of 99 women with breast cancer were randomly assigned to one of two groups. In the HA-CMC group (n = 50), a mixed HA-CMC was applied to the surface of the pectoralis major and serratus anterior muscle after TM. In the control group (n = 49), TM was performed without the use of HA-CMC. The primary outcomes were ROM of the shoulder and motion-related pain assessed using a numeric rating scale measured before surgery (T0) and 3 (T1) and 6 months (T2) after surgery. Secondary outcomes included disabilities of the arm, shoulder, and hand (DASH) and the pectoralis minor length test. Compared with the control group, the HA-CMC group showed greater reductions in postoperative restriction of total shoulder ROM (sum of flexion and horizontal abduction) at 3 months (10.20°, P = 0.004). Mean pain levels related to flexion and horizontal abduction were significantly lower in the HA-CMC group (-1.32 and -0.93, respectively, P < 0.05). The DASH score was lower (-4.94; P = 0.057) in the HA-CMC group at T2. No adverse effect was observed in either group. These results provide evidence that HA-CMC may provide pain relief and improve ROM of the shoulder without causing adverse effects. The effect on pectoralis tightness should be investigated in further studies.

Lubricin in human breast tissue expander capsules

Capsular contraction is the most common complication of breast reconstruction surgery. While presence of the contractile protein alpha smooth muscle actin (α-SMA) is considered among the causes of capsular contraction, the exact etiology and pathophysiology is not fully understood. The objective of this study was to investigate the possible role of lubricin in capsular formation and contraction by determining the presence and distribution of the lubricating protein lubricin in human breast tissue expander capsules. Related aims were to evaluate select histopathologic features of the capsules, and the percentage of cells expressing α-SMA, which reflects the myofibroblast phenotype. Capsules from tissue expanders were obtained from eight patients. Lubricin, at the tissue-implant interface, in the extracellular matrix, and in cells, and α-SMA-containing cells were evaluated immunohistochemically. The notable finding was that lubricin was identified in all tissue expander capsules: as a discrete layer at the tissue-implant interface, extracellular, and intracellular. There was a greater amount of lubricin in the extracellular matrix in the intimal-subintimal zone when compared with the tissue away from the implant. Varying degrees of synovial metaplasia were seen at the tissue-implant interface. α-SMA-containing cells were also seen in all but one patient. The findings might help us better understand factors involved in capsule formation.

Effect of hyaluronic acid-carboxymethylcellulose solution on perineural scar formation after sciatic nerve repair in rats

Background

Scar tissue formation is the major cause of failure in peripheral nerve surgery. Use of a hyaluronic acid-carboxymethylcellulose (HA-CMC) membrane (Seprafilm) as a solid anti-adhesion barrier agent is one of the therapeutic approaches to reduce postoperative scar tissue formation. However, a solid membrane may not be suitable for repair of a weak peripheral nerve site. This study examined the effect of HA-CMC solution on perineural scar formation after peripheral nerve repair in rats.

Methods

The sciatic nerves of 40 rats were transected and then immediately repaired using 10-0 nylon. The nerves were divided randomly into two groups. Saline and HA-CMC solution were applied topically to the nerve repair sites in the control and experimental groups, respectively. Reoperation was performed at 3, 6, 9, and 12 weeks to assess scar tissue formation. The assessment included the quality of wound healing, presence of perinueral adhesion, cellular components of the scar tissue, thickness of the scar tissue and histomorphological organization of the repair site.

Results

Topical application of the HA-CMC solution significantly decreased the macroscopic nerve adherence score and the numbers of the cellular components such as fibroblasts and inflammatory cells (p < 0.05, Mann-Whitney U-test). The scar tissue formation index was significantly lower in the experimental group at 12 weeks than that in the control group (p < 0.05, Mann-Whitney U-test). The grading scores of the histomorphological axonal organization at the repair site were significantly higher in the experimental group than those in the control group at 12 weeks (p < 0.05, Mann-Whitney U-test). No evidence of wound dehiscence or inflammatory reactions against the HA-CMC solution was noted.

Conclusions

Topical application of a HA-CMC solution is effective in reducing the perineural scar formation and adhesion after sciatic nerve repair in rats, and is effective in promoting peripheral nerve regeneration at the repair site.