A new material for prevention of peritendinous fibrotic adhesions after tendon repair: oxidised regenerated cellulose (Interceed), an absorbable adhesion barrier

Use of a bioresorbable polylactide sheet (OrthoWrap® Bioresorbable sheet) on tendon healing after extensor tendon repair: a controlled clinical trial

BACKGROUND

Adhesion formation poses a significant challenge for both patients and hand surgeons following tendon repair. One common strategy to prevent adhesion formation is the use of physical barriers. This study aimed to compare the outcomes of extensor tendon repair with and without the application of the OrthoWrap® bioresorbable Sheet, specifically in terms of adhesion prevention.

METHODS

This triple-blind randomized clinical trial was conducted on patients with trauma to the extensor zone VI tendons. Participants were randomly assigned to one of two groups. In the intervention group, OrthoWrap® bioresorbable Sheet was applied in addition to the standard tendon repair protocol. Over a three-month follow-up period, the Visual Analogue Scale (VAS) score, extension lag, and metacarpophalangeal joint flexion were assessed. Additionally, the mobility of the proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints was evaluated using the Strickland classification.

RESULTS

A total of 42 patients in the OrthoWrap® group and 43 in the control group were evaluated over the three-month period. Both groups showed a significant reduction in mean extension lag at the metacarpophalangeal joint over time. No significant condition-by-time interactions were found for MP joint flexion or VAS scores (p > 0.05). However, significant improvements in MP joint flexion and VAS scores were observed over time. The OrthoWrap® group demonstrated significantly more favorable outcomes compared to the control group.

CONCLUSION

The clinical application of OrthoWrap® in extensor tendon repair demonstrated statistically significant but modest improvements in extension lag (2.5°). While patients treated with OrthoWrap® showed better outcomes in Strickland's classification, the clinical significance of these small differences and their impact on patient function requires further investigation.

TRIAL REGISTRATION

IRCT, IRCT20180627040252N3. Registered 20,220,617, Https//irct.behdasht.gov.ir/trial/56,652.

Animal neuropathic pain aroused by conglutinating oxidative regenerative cellulose on dorsal root ganglion

Neuropathic pain arises as a consequence of injury or disease in the peripheral or central nervous system. Clinical cases have shown that spine postoperative chronic neuropathic pain remains a troublesome issue in medical treatment due to the presence of various degrees of peridural fibrosis and different inflammatory factors after spinal surgery. To address this issue, we developed a new neuropathic mice model that successfully simulates the real clinical situation by applying oxidative regenerative cellulose to L5 DRG (dorsal root ganglion). Behavior tests were done by von Fray and thermal stimuli. ELISA and real-time PCR were employed to detect the expression of genes involved in neuropathic pain. This model not only successfully induces chronic pain but also causes membrane thickening, non-neuronal cell recruitment, and a local increase of TNFα and interleukin-6. Additionally, this model did not cause neuron loss in the affected DRG, which mimics the characteristics of sticky tissue-induced neuropathic pain after clinic surgery. Based on this model, we administrated a TNF inhibitor to mice and successfully reduced mechanical allodynia after DRG surgery. In this study, the developed animal model may be a novel platform for delivering neuropathic pain treatments, such as target-based drug discovery or personalized diagnostic approaches.

Interceed combined with bone marrow mesenchymal stem cells improves endometrial receptivity of intrauterine adhesion

Background

This study aimed to investigate the impact of intrauterine adhesions (IUA) therapy and endometrial receptivity by implanting autologous bone marrow mesenchymal stem cells (BMSCs) into the Interceed and subsequently placing them in the uterine cavity of rats.

Methods

Fifty rats were divided into 5 groups according to the random number table method (10 rats in each group). Following the development of the IUA model through mechanical injury, the animals were categorized into different treatment groups: the IUA model (intrauterine perfusion of saline), Interceed therapy (intrauterine placement of Interceed), BMSCs therapy (intrauterine perfusion of BMSCs), BMSCs + Interceed therapy (intrauterine placement of BMSCs + Interceed), and a control group (intrauterine perfusion of saline). The Hematoxylin-eosin (HE) staining technique was employed to identify and assess the pathological alterations in the endometrium. Additionally, it facilitated the quantification of endometrial glands and the determination of endometrial thickness. Masson staining was used to detect fibrosis in rat uterus. The number of microvascular density (MVD) was detected by immunohistochemistry (IHC). Real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot were used to detect the levels of leukemia inhibitory factor (LIF), integrin ανβ3, and vascular endothelial growth factor (VEGF) in uterine tissue. Male and female rats were combined in cages for reproductive and conception evaluation.

Results

In comparison to the control, the number of endometrial glands in the IUA model was significantly reduced, and the degree of endometrial thinning and fibrosis was significantly increased (p < 0.05). Compared with the IUA model, the number of endometrial glands did not exhibit any significant alterations in endometrial thickness and MVD number. The expressions of LIF, integrin ανβ3, and VEGF in the uterine tissue were not significantly improved with Interceed therapy, resulting in no significant improvement in the pregnancy rate (p > 0.05). The number of endometrial glands, endometrial thickness, and MVD in the BMSCs therapy group were significantly increased. Moreover, the expressions of LIF, integrin ανβ3, and VEGF in uterine tissue exhibited a significant increase, leading to a comparatively higher pregnancy rate (p < 0.05). In the BMSCs + Interceed therapy group, the number of endometrial glands, endometrial thickness, and MVD were significantly increased, and the expressions of LIF, integrin ανβ3, and VEGF in uterine tissue were significantly increased as well, along with a corresponding rise in the pregnancy rate (p < 0.05).

Conclusion

The intrauterine placement of Interceed combined with BMSCs in IUA rats can thicken the damaged endometrium, increase the number of glands, promote endometrial angiogenesis, improve endometrial receptivity, and increase the rate of pregnancy in IUA rats.

Current trends in the prevention of adhesions after zone 2 flexor tendon repair

Treating flexor tendon injuries within the digital flexor sheath (commonly referred to as palmar hand zone 2) presents both technical and logistical challenges. Success hinges on striking a delicate balance between safeguarding the surgical repair for tendon healing and initiating early rehabilitation to mitigate the formation of tendon adhesions. Adhesions between tendon slips and between tendons and the flexor sheath impede tendon movement, leading to postoperative stiffness and functional impairment. While current approaches to flexor tendon repair prioritize maximizing tendon strength for early mobilization and adhesion prevention, factors such as pain, swelling, and patient compliance may impede postoperative rehabilitation efforts. Moreover, premature mobilization could risk repair failure, necessitating additional surgical interventions. Pharmacological agents offer a potential avenue for minimizing inflammation and reducing adhesion formation while still promoting normal tendon healing. Although some systemic and local agents have shown promising results in animal studies, their clinical efficacy remains uncertain. Limitations in these studies include the relevance of chosen animal models to human populations and the adequacy of tools and measurement techniques in accurately assessing the impact of adhesions. This article provides an overview of the clinical challenges associated with flexor tendon injuries, discusses current on- and off-label agents aimed at minimizing adhesion formation, and examines investigational models designed to study adhesion reduction after intra-synovial flexor tendon repair. Understanding the clinical problem and experimental models may serve as a catalyst for future research aimed at addressing intra-synovial tendon adhesions following zone 2 flexor tendon repair.

Evaluating the Effectiveness of Commercially Available Antiadhesion Tendon Protector Sheets in Tendon Repair Surgery Versus Tendon Repair Surgery Alone: A Preclinical Model Study

PURPOSE

Adhesion formation is the major complication after tendon repairs that halts functional restoration and causes disability in patients. This study aimed to compare the antiadhesion efficacy of two tendon protector sheets using a previously established turkey flexor tendon model.

METHODS

Twenty-four adult Bourbon Red turkeys were randomized into three groups: (1) control, (2) type I collagen-glycosaminoglycan (Collagen-GAG), and (3) hyaluronic acid. In each group, the flexor digitorum profundus tendon of the middle digit was sharply lacerated at the proximal interphalangeal joint level. All operated feet were immobilized until sacrifice 6 weeks after the surgery. After sacrifice, the repaired and normal digits were collected for biomechanical testing, adhesion scores, histological examination, and adhesion-related gene expression analysis.

RESULTS

At 42 days after tendon repair, the normalized work of flexion of the repaired digit was the lowest in the Collagen-GAG group. The Collagen-GAG group also had the lowest gross adhesion score, indicating minimal adhesion. The hyaluronic acid group showed lower adhesion scores compared with the control, but the difference was not statistically significant. Microscopically, the Collagen-GAG group had a significantly lower histological adhesion score than the control group. In the Collagen-GAG group, the gene expression levels of WNT3A, WNT5A, and WNT7A were suppressed.

CONCLUSIONS

In an avian model of flexor tendon repair, the application of tendon protector sheets reduces peritendinous fibrotic tissue formation histologically.

CLINICAL RELEVANCE

There are currently limited commercially available products to reduce postoperative peritendinous adhesions. Further validation is needed to confirm the effectiveness of tendon protector sheets in improving surgical outcomes following tendon repairs.

The results of preventing postoperative achilles tendon adhesion using cross-linked and non-cross-linked hyaluronic acid, a study with rat model

BACKGROUND

There are many adhesion barrier materials, cross-linked or non-cross-linked hyaluronic acid (HA), used during surgeries.

PURPOSE

This study investigates the efficacy of cross-linked and non-cross-linked HA in preventing Achilles tendon adhesions. We hypothesized that non-cross-linked HA may be more effective than cross-linked HA in preventing Achilles tendon adhesions following injury and repair.

METHODS

Twenty male Sprague Dawley rats, totaling 40 legs, underwent Achilles tendon transection and repair. Following the surgery, they were treated simultaneously with cross-linked and non-cross-linked HA formulations. The rats were divided into four groups: a positive control group, a group treated with BMC non-cross-linked HA gel, a group treated with DEFEHERE cross-linked HA gel, and a group treated with ANIKA cross-linked HA gel. Four weeks after surgery, macroscopic evaluation of peritendinous adhesion and histological analysis were conducted to assess the effectiveness of the treatments.

RESULTS

Non-cross-linked BMC HA demonstrated superior efficacy in preventing tendon adhesions compared to cross-linked HA and control groups. Histological analysis confirmed reduced adhesion severity in the non-cross-linked HA group (P < 0.05). The findings support the potential of non-cross-linked HA as a treatment to inhibit tendon adhesions. Further research, including clinical trials, is warranted to validate these results in human subjects.

CONCLUSIONS

Non-cross-linked BMC HA had significantly lower tendon adhesions parameters and better healing scores in histological analysis than cross-linked HA and control group did. Non-cross-linked HA holds promise as a potential treatment to inhibit the formation of such adhesions.

Prevention of Adhesions after Bone Fracture Using a Carboxymethylcellulose and Polyethylene Oxide Composite Gel in Dogs

The formation of adhesions is a common complication following traumatic injuries and surgical procedures, often resulting in pain, stiffness, and loss of function. This study aimed to evaluate the feasibility and safety of using a composite material comprising of carboxymethylcellulose (CMC), polyethylene oxide (PEO), and calcium chloride, for preventing adhesions between muscle and bone during the healing stage, as well as its effect on the bone healing process. Ten healthy purpose-bred laboratory Beagle dogs were randomly subjected to two consecutive operations with a 6-month interval, alternating between left and right forelimbs. On the left forelimb an osteotomy at the ulna was performed, while on the right forelimb the same procedure was supplemented by the application of the anti-adhesion agent in the osteotomy site prior to closure. Clinical, diagnostic imaging, macroscopic, and histological evaluations were performed at various time points. The results showed no significant differences in surgical site perimeter (p = 0.558), lameness (p = 0.227), and radiographic bone healing (p = 0.379) between the two groups. However, the macroscopic (p = 0.006) and histological assessments revealed significantly lower adhesion scores (p = 0.0049) and better healing (p = 0.0102) in the group that received the anti-adhesion agent. These findings suggest that the CMC/PEO composite material is a safe and potentially effective intervention for preventing post-traumatic and post-surgical adhesions in canine patients without compromising bone healing. Further research is warranted to fully characterize the clinical benefits of this approach.

A Systematic Review of Anti-Adhesion Agents in Hand Trauma

Adhesions following hand surgery are common, leading to stiffness, which compromises the functional outcomes for the patient. The objective of this study was to conduct a systematic review to analyze the role of antiadhesive barriers in surgery for hand trauma. A comprehensive literature search was conducted using PubMed/MEDLINE, Embase and the Cochrane Central Register of Controlled Trials, in line with the Preferred Reporting Items for Systematic reviews and Meta-Analysis guidelines. The inclusion criteria included both randomized and non-randomized control studies in patients aged 18 or over, with the intervention of an anti-adhesive barrier compared against traditional repair without a barrier in patients with hand trauma, including nerve, fracture, and tendon injury. The primary outcome measure of interest was range of movement (ROM) after operative surgery. Secondary outcomes of interest included further surgery, reported stiffness, complications, quality of life, and time to return to work. A total of 8450 records were identified; 7 studies fulfilled the eligibility criteria and were included. Seven anti-adhesive barriers were included in the review. Three agents (amnion, MASTBiosurgery Surgiwrap antiadhesive film, and acellular dermal matrix [ADM]) demonstrated statistically significant improvements in ROM postoperatively; however, all 3 studies demonstrated a risk of bias. This review highlights the paucity of high-quality studies demonstrating any clear advantage of using anti-adhesive barriers in hand surgery; however, there is some evidence to suggest that amnion, the MAST adhesion barrier film and ADM may have favorable results as an antiadhesive barrier in hand surgery, but further high-quality research is required to quantify this effect.

Quantitative Assessment of Calf Muscle Volume, Strength, and Quality After Achilles Tendon Rupture Repair: A 1-Year Prospective Follow-up Study

BACKGROUND

A number of studies have reported that calf muscle atrophy is a common long-term problem after Achilles tendon repair; however, there is still a lack of data concerning early postoperative morphological changes in the calf muscle after surgery.

PURPOSE

To investigate changes over time in calf muscle volume and fatty degeneration during 1 year after Achilles tendon repair.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A prospective 1-year serial magnetic resonance imaging study was carried out with 20 patients who underwent tendon repair for unilateral acute Achilles tendon rupture. The magnetic resonance imaging assessment in addition to clinical and functional evaluations was performed at 1, 3, 6, and 12 months after surgery. The muscle volume of the medial and lateral gastrocnemius, soleus, and flexor hallucis longus (FHL) and fatty degeneration of the medial and lateral gastrocnemius and soleus were measured for the calf muscles, and the relative volume and fatty degeneration changes in the affected leg compared with the healthy contralateral leg were calculated as a percentage ([injured/healthy control] × 100) to assess structural changes over time.

RESULTS

Muscle volumes of the medial gastrocnemius, lateral gastrocnemius, soleus, and FHL were 92.3%, 92.8%, 84.6%, and 95.9% at 12 months after surgery, respectively. Medial and lateral gastrocnemius and FHL muscle volumes improved over time and recovered to almost equal to that of the healthy side at 12 months after surgery. The soleus muscle volume did not recover significantly over time and was statistically significantly smaller than that of the healthy side at 12 months (P = .029). Fatty degeneration rates of the medial gastrocnemius, lateral gastrocnemius, and soleus were 118.2%, 113.9% and 121.1% at 12 months after surgery, respectively. Fatty degeneration of the medial and lateral gastrocnemius did not change significantly, but there was a statistically significant increase in fatty degeneration of the soleus over time (P < .001).

CONCLUSION

Within the triceps surae muscle, the soleus was the most negatively affected by injury and repair for both muscle volume and fatty degeneration. Postoperative management to recover the soleus muscle function before a return to sporting activities should be considered in the future.

Cyclical endometrial repair and regeneration: Molecular mechanisms, diseases, and therapeutic interventions

The endometrium is a unique human tissue with an extraordinary ability to undergo a hormone-regulated cycle encompassing shedding, bleeding, scarless repair, and regeneration throughout the female reproductive cycle. The cyclical repair and regeneration of the endometrium manifest as changes in endometrial epithelialization, glandular regeneration, and vascularization. The mechanisms encompass inflammation, coagulation, and fibrinolytic system balance. However, specific conditions such as endometriosis or TCRA treatment can disrupt the process of cyclical endometrial repair and regeneration. There is uncertainty about traditional clinical treatments' efficacy and side effects, and finding new therapeutic interventions is essential. Researchers have made substantial progress in the perspective of regenerative medicine toward maintaining cyclical endometrial repair and regeneration in recent years. Such progress encompasses the integration of biomaterials, tissue-engineered scaffolds, stem cell therapies, and 3D printing. This review analyzes the mechanisms, diseases, and interventions associated with cyclical endometrial repair and regeneration. The review discusses the advantages and disadvantages of the regenerative interventions currently employed in clinical practice. Additionally, it highlights the significant advantages of regenerative medicine in this domain. Finally, we review stem cells and biologics among the available interventions in regenerative medicine, providing insights into future therapeutic strategies.

Shielding the Nerve: A Systematic Review of Nerve Wrapping to Prevent Adhesions in the Rat Sciatic Nerve Model

BACKGROUND

Peripheral nerve pathology is frequently encountered in clinical practice among peripheral nerve and extremity surgeons. One major factor limiting nerve regeneration and possibly leading to revision surgeries is the development of traumatic or postoperative adhesions and scarring around nerves. In experimental models, different materials have been studied to limit scar tissue formation when wrapped around nerves.

METHODS

A systematic review of studies describing nerve-wrapping materials in a non-transectional rat sciatic nerve model was performed following the PRISMA guidelines. Literature describing nerve-wrapping methods for the prevention of peripheral nerve scarring in rat sciatic nerve models was identified using PubMed and Web of Science, scanned for relevance and analyzed.

RESULTS

A total of 15 original articles describing 23 different materials or material combinations for nerve wrapping were included. The heterogeneity of the methods used did not allow a meta-analysis, thus, a systematic review was performed. Out of 28 intervention groups, 21 demonstrated a preventive effect on scar tissue formation in at least one qualitative or quantitative assessment method.

CONCLUSIONS

The analyzed literature describes a variety of materials from different origins to limit peripheral nerve scarring and adhesions. Thus, a scar-preventive effect by wrapping peripheral nerves as adhesion prophylaxis seems likely. However, a quantitative comparison of the studies to identify the optimal material or technique is not possible with the diversity of used models and study designs. Therefore, further research needs to be performed to identify the optimal nerve wraps to be used routinely in clinical practice.

Flexor Tendon Adhesion Formation: Current Concepts

Over the years, various physical and chemical/biological methods of inhibiting adhesion formation have been developed, focusing on how to suppress healing around the tendon and not inhibit healing within the tendon. Unfortunately, however, these methods are accompanied by drawbacks, both large and small, and no absolute antiadhesion method capable of maintaining tendon repair strength has yet been developed. Recent innovations in biomaterials science and tissue engineering have produced new antiadhesion technologies, such as barriers combined with cytokines and cells, which have improved outcomes in animal models, and which may find clinical relevance in the future.

Barrier materials for prevention of surgical adhesions: systematic review

BACKGROUND

Postoperative surgical adhesions constitute a major health burden internationally. A wide range of materials have been evaluated, but despite constructive efforts and the obvious necessity, there remains no specific barrier widely utilized to prevent postoperative adhesion formation. The aim of this study was to highlight and characterize materials used for prevention of postoperative surgical adhesions in both animal and human studies.

METHODS

A systematic review was performed of all original research articles presenting data related to the prevention of postoperative adhesions using a barrier agent. All available observational studies and randomized trials using animal models or human participants were included, with no restrictions related to type of surgery. PubMed and Embase databases were searched using key terms from inception to August 2019. Standardized data collection forms were used to extract details for each study and assess desirable characteristics of each barrier and success in animal and/or human studies.

RESULTS

A total of 185 articles were identified for inclusion in the review, with a total of 67 unique adhesion barrier agents (37 natural and 30 synthetic materials). Desirable barrier characteristics of an ideal barrier were identified on review of the literature. Ten barriers achieved the primary outcome of reducing the incidence of postoperative adhesions in animal studies followed with positive outputs in human participants. A further 48 materials had successful results from animal studies, but with no human study performed to date.

DISCUSSION

Multiple barriers showed promise in animal studies, with several progressing to success, and fulfilment of desirable qualities, in human trials. No barrier is currently utilized commonly worldwide, but potential barriers have been identified to reduce the burden of postoperative adhesions and associated sequelae.

Recent trends in therapeutic strategies for repairing endometrial tissue in intrauterine adhesion

Intrauterine adhesion (IUA) is a common gynaecological disease that develops from infection or trauma. IUA disease may seriously affect the physical and mental health of women of childbearing age, which may lead to symptoms such as hypomenorrhea or infertility. Presently, hysteroscopic transcervical resection of adhesion (TCRA) is the principal therapy for IUAs, although its function in preventing the recurrence of adhesion and preserving fertility is limited. Pharmaceuticals such as hormones and vasoactive agents and the placement of nondegradable stents are the most common postoperative adjuvant therapy methods. However, the repair of injured endometrium is relatively restricted due to the different anatomical structures of the endometrium. Recently, the treatment outcome of IUAs has improved with the advancement of hysteroscopic techniques. In particular, the application of bioactive scaffolds combined with tissue engineering technology has proven to have high therapeutic potential or endometrial repair in IUA treatment. Herein, this review has summarized past therapeutic strategies, including postoperative adjuvant therapy, cell or therapeutic molecular delivery therapy methods and bioactive scaffold-based tissue engineering methods. Therefore, this review presented the recent therapeutic strategies for repairing endometrium treatment and pointed out the issues of clinical concern to provide alternative methods for the management of IUAs.

A nano chitosan membrane barrier prepared via Nanospider technology with non-toxic solvent for peritoneal adhesions' prevention

Peritoneal adhesion is one of the most common postsurgical complications and can cause bowel obstruction, pelvic pain, and infertility. Setting up a physical barrier directly between the injured site and surrounding tissues is an effective solution for preventing this adverse situation. This study investigated a chitosan electrospun membrane (CSEM) as a potent anti-adhesion barrier, which was prepared by a needleless technology called Nanospider. Scanning electron microscopy revealed that CSEM is a laminated nanofiber with good mechanical properties. The fiber is uniform with the diameter distributing in the range of 100-120 nm. The tensile strength can reach 27.45 ± 6.30 MPa with a maximum elongation at break of 18.50 ± 1.44%, which makes it stick easily to damaged parts but not to be easily damaged by tissue friction. The growth of S. aureus on CSEM was 59.18% lower than the control at 10 h, which indicates its better antibacterial property. In addition, CSEM has good coagulant and biocompatibility characteristics. It can perform hemostatic function within 10 min and the L929 mouse fibroblast viability on it was 92.18% ± 1.08% on the seventh day. In vivo experiments indicated that CSEM significantly prevented peritoneal adhesions within four weeks after surgery with wound surface coverage. These results indicate that CSEM is a promising anti-adhesion barrier material.

Development of poly(D,L-lactic-co-glycolic acid) films coated with biomembrane-mimicking polymers for anti-adhesion activity

A physical barrier is one of the most effective strategies to alleviate excessive postoperative adhesion (POA) between tissues at an injury site. To overcome the limitations of current polymeric film-type physical barriers, we suggest a film of poly(lactic-co-glycolic acid) (PLGA) that is non-covalently coated with poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-co-n-butyl methacrylate (BMA)) (PMB). While maintaining the degradability and mechanical properties of PLGA, the PMB coating introduces strong anti-adhesive properties to the film by forming a zwitterionic MPC-based surface through the hydrophobic interactions between BMA moieties and PLGA. Compared to SurgiWrap®, the commercially available poly(lactic acid)-based anti-adhesive film against POA, the PMB-coated PLGA film is much more inhibitory against protein adsorption and fibroblast adhesion, processes that are crucial to the POA process. PMB coating also inhibits the expression of fibronectin containing extra domain A (FN-EDA), α-smooth muscle actin (α-SMA), and collagen type IV alpha 2 (COL4A2), which are marker genes and proteins involved in fibroblast activation and excessive fibrosis during POA. Such inhibitory activities are clearly observed in a 3-dimensional culture of fibroblasts within a collagen matrix, which mimics the in vivo environment of an injury site, as well as in a 2-dimensional culture. The kinetics and the stability of the PMB coating suggest potential future clinical use to coat PLGA films to create a film-type anti-adhesion barrier that overcomes the limitations of current products.

Advancement of Biomaterial-Based Postoperative Adhesion Barriers

Postoperative peritoneal adhesion (PPA) is a prevalent incidence that generally happens during the healing process of traumatized tissues. It causes multiple severe complications such as intestinal obstruction, chronic abdominal pain, and female infertility. To prevent PPA, several antiadhesion materials and drug delivery systems composed of biomaterials are used clinically, and clinical antiadhesive is one of the important applications nowadays. In addition to several commercially available materials, like film, spray, injectable hydrogel, powder, or solution type have been energetically studied based on natural and synthetic biomaterials such as alginate, hyaluronan, cellulose, starch, chondroitin sulfate, polyethylene glycol, polylactic acid, etc. Moreover, many kinds of animal adhesion models, such as cecum abrasion models and unitary horn models, are developed to evaluate new materials' efficacy. A new animal adhesion model based on hepatectomy and conventional animal adhesion models is recently developed and a new adhesion barrier by this new model is also developed. In summary, many kinds of materials and animal models are studied; thus, it is quite important to overview this field's current progress. Here, PPA is reviewed in terms of the species of biomaterials and animal models and several problems to be solved to develop better antiadhesion materials in the future are discussed.

The usefulness of re-attachability of anti-adhesive cross-linked gelatin film and the required physical and biological properties

BACKGROUND

To overcome the unfavorable issues associated with conventional anti-adhesive HA/CMC film, we developed an anti-adhesive thermally cross-linked gelatin film.

OBJECTIVE

We tried to clarify the re-attachability of the film and the required properties concerning the film thickness, stiffness and anti-adhesion effect.

METHODS

To determine the optimal thickness, 5 kinds of the thickness of gelatin film and the conventional film were analyzed by the tensile test, shearing test, buckling test and tissue injury test. Finally, using the optimal film thickness, we tried to clarify the anti-adhesion effect of the reattached film.

RESULTS

The tensile and shearing test showed gelatin films ≥30 μm thick had greater tensile strength and a smaller number of film fractures, than the conventional film. The buckling and tissue injury test showed gelatin films ≥60 μm thick had higher buckling strength and worse injury scores than the conventional film. The anti-adhesive effect of re-attached gelatin film using optimal thickness (30-40 μm) found the anti-adhesion score was significantly better than that of the control.

CONCLUSIONS

Provided it has an optimal thickness, gelatin film can be reattached with enough physical strength not to tear, safety stiffness not to induce tissue injury, and a sufficient anti-adhesion effect.

Multifunctional Supramolecular Hydrogel for Prevention of Epidural Adhesion after Laminectomy

Postoperative epidural adhesion remains a clinically challenging problem in spine surgery. Currently there are no effective and safe antifibrotic and antiadhesion biomaterials that have been specifically developed for this complication in clinical practice. Herein we designed and engineered an advanced antiadhesion hydrogel with multiple functionalities, including temperature-responsive gelation, self-healing, tissue adhesiveness, antioxidation, anti-inflammation, and antifibrosis. This multifunctional supramolecular hydrogel can be facilely constructed by integrating three functional modules, i.e., a thermosensitive triblock copolymer, poloxamer 407 (PX); a reactive oxygen species-eliminating and anti-inflammatory nanoparticle (TPCD NP); and an adhesion-enhancing compound, tannic acid (TA). The optimal formulation (PXNT) was hierarchically screened based on in vitro properties and in vivo activities. Therapeutically, local treatment with PXNT hydrogel effectively prevented epidural fibrosis and adhesion after laminectomy in both rats and rabbits. Of note, PXNT hydrogel showed more beneficial efficacy than different control thermosensitive hydrogels and a commercially available barrier product, Interceed. Mechanistically, PXNT hydrogel significantly attenuated local oxidative stress, inhibited inflammatory responses, and reduced fibrotic tissue formation. Moreover, treatment with PXNT hydrogel did not cause systemic adverse effects and neurological symptoms. Consequently, PXNT hydrogel is a highly promising biomaterial for preventing postlaminectomy epidural adhesion and adhesions after other surgeries.

Application of Traditional Chinese Medicines in Postoperative Abdominal Adhesion

Adhesion is a frequent complication after abdominal surgery. Although various methods have been applied to prevent and treat postoperative abdominal adhesion (PAA), few modern drugs designed for clinical applications have reached the expected preventive or therapeutic effect so far. There is an imperative to develop some new strategies for the treatment of PAA. Traditional Chinese medicine (TCM) has been widely practiced for thousands of years and played an indispensable role in the prevention and treatment of diseases. Modern medicine researchers have accepted the therapeutic effects of many active components derived from Chinese medicinal herbs. The review stresses the most commonly used TCM treatment, including Chinese medicinal herbals and monomers, TCM formulas, and acupuncture treatment.

Intraperitoneal Administration of Telmisartan Prevents Postsurgical Adhesion Band Formation

BACKGROUND

Angiotensin II receptor blockers (ARBs) have a potential role in reducing inflammation and fibrosis. We have integrated systems and molecular biology approaches to investigate the therapeutic potential of ARBs in preventing postsurgical adhesion band formation.

MATERIAL AND METHODS

we have followed the ARRIVE guidelines point by point during experimental studies. Telmisartan (1 and 9 mg/kg), valsartan (1 and 9 mg/kg), and losartan (1 and 10 mg/kg) were administered intraperitoneally in different groups of male albino Wistar rat. After 7 d of treatment, macroscopic evidence and score of fibrotic bands based on scaling methods was performed. Moreover, the anti-inflammatory and antifibrosis effects of telmisartan on reduction of fibrotic bands were investigated by using histopathology, ELISA, and real-time polymerase chain reaction methods.

RESULTS

Telmisartan, but not losartan or valsartan, prevented the frequency as well as the stability of adhesion bands. Telmisartan appears to elicit anti-inflammatory responses by attenuating submucosal edema, suppressing proinflammatory cytokines, decreasing proinflammatory cell infiltration, and inhibiting oxidative stress at the site of peritoneal surgery. We also showed that telmisartan prevents fibrotic adhesion band formation by reducing excessive collagen deposition and suppression of profibrotic genes expression at the peritoneum adhesion tissues.

CONCLUSIONS

These results support the potential application of telmisartan in preventing postsurgical adhesion band formation by inhibiting key pathologic responses of inflammation and fibrosis in postsurgery patients.

Polypropylene composite hernia mesh with anti-adhesion layer composed of polycaprolactone and oxidized regenerated cellulose

Hernia surgeries are at the top of the general surgery operations. However, visceral adhesion, which is one of the worst complications of these operations, is still a major problem. One of the most preferred methods to prevent adhesion is the use of biomaterials. Polypropylene (PP) mesh is frequently preferred product in clinical applications owing to its mechanically robust structure against deformation within the body. However, PP meshes do not have anti-adhesive properties. Oxidized regenerated cellulose (ORC), on the other hand, is one of the most preferred products in preventing the adhesion in clinical use. ORC is not easily processable due to solubility limitations; and it must be used externally. In this study, for the first time, we designed a composite mesh structure with ORC and produced an antibacterial and anti-adhesive double-sided mesh by electro-spinning ORC micro-particles with poly(ε‑caprolactone) (PCL) on PP mesh to form a composite structure. We conducted in vitro cell culture studies to determine bio-compatibility performances. We evaluated the anti-adhesion and comprehensive bio-compatibility studies through in vivo experiments. The results revealed that ORC presence and optimization of ORC degradation by coating with PCL play an important role in adhesion prevention and introduced a product prototype with efficient anti-adhesion properties.

Battling adhesions: from understanding to prevention

Adhesions represent a major burden in clinical practice, particularly following abdominal, intrauterine, pericardial and tendon surgical procedures. Adhesions are initiated by a disruption in the epithelial or mesothelial layer of tissue, which leads to fibrin adhesion sites due to the downregulation of fibrinolytic activity and an increase in fibrin deposition. Hence, the metabolic events involved in tissue healing, coagulation, inflammation, fibrinolysis and angiogenesis play a pivotal role in adhesion formation. Understanding these events, their interactions and their influence on the development of post-surgical adhesion is crucial for the development of effective therapies to prevent them. Mechanical barriers, antiadhesive agents and combination thereof are customarily used in the battle against adhesions. Although these systems seem to be effective at reducing adhesions in clinical procedures, their prevention remains still elusive, imposing the need for new antiadhesive strategies.

Tendon Adhesions: A Novel Method of Objectively Measuring Adhesions by Assessing Tendon Glide Through a Soft Tissue Envelope in a Rat Model

PURPOSE

To develop a rat model of extra-synovial tendon adhesions that will enable accurate testing of scar barriers and adhesion inhibiting treatments to facilitate future research.

METHODS

Thirty-six 6-month-old male Sprague-Dawley rats were randomized to one of the 3 groups of 12. In Group A, the middle one-third portion of the left Achilles tendon was excised. In Group B, the tendon and soft tissue bed was abraded with steel wool. In Group C, a silk suture was sewn along the tendon. The right hind limbs served as controls. At 4 weeks, biomechanical testing was performed on the bilateral hind limbs. The Achilles tendon was cut at the gastrocnemius-tendon junction proximal to the "adhesion zone" (or analogous level in the control limb). The calcaneal insertion of the Achilles was attached to a tensiometer. The force needed to pull the tendon out of its soft tissue envelope at a fixed rate was measured.

RESULTS

Three rats were excluded because of complications during data collection. Pair-wise comparison testing was performed, comparing the mean peak force to pull the Achilles tendon from its soft tissue envelope in 33 control limbs and the contralateral limb from each group. The average peak force for the cut tendon group (A) was 20.1 N, 18.8 N in the steel wool group (B), and 21.1 N in the suture group (C). The average peak force in the control limbs was 15.6 N. There was a significant difference noted in peak forces between the control limbs and each experimental group.

CONCLUSIONS

A consistent and statistically increased force was necessary to pull a rodent Achilles tendon from an adhesion-induced tissue bed compared with controls. No statistical difference was detected between experimental groups.

CLINICAL RELEVANCE

Our study demonstrates an objective method of biomechanical tendon adhesion assessment in a rat model.

Prevention of Peritendinous Adhesion Formation After the Flexor Tendon Surgery in Rabbits: A Comparative Study Between Use of Local Interferon-α, Interferon-β, and 5-Fluorouracil

BACKGROUND

Peritendinous adhesion is the most common complication after tendon surgery, particularly in zone II of the hand. Prevention of inflammation around the tendon, which develops after trauma and surgery, can decrease the tendon adhesion formation. This study compares the effect of some anti-inflammatory cytokines with 5-fluorouracil (5-FU) on the tensile strength and in prevention of peritendinous adhesion formation.

METHODS

Sixteen rabbits were allocated equally into 4 groups. Tendons of the index and ring fingers in zone II of the right hind paw were cut in all animals and then repaired. Interferon (IFN)-α in group 1, 5-FU in group 2, normal saline in group 3, and IFN-β in group 4 were locally applied to the repaired sites. Three weeks later, tensometric and histopathologic evaluations were performed.

RESULTS

The force required for removing the tendon from the sheath was not different between the groups (P = 0.130), but the time required for removal was significantly shorter in 5-FU group (P = 0.049). The strength of repair was not different between the groups in terms of force and time needed for rupture (P = 0.11 and 0.67, respectively). In histopathologic examination, normal architecture of the tendon and peritendon environment was less disturbed in the IFN groups, especially in IFN-β specimens.

CONCLUSIONS

Local application of 5-FU significantly reduced peritendinous adhesion. Local IFN-α and IFN-β had no significant effect on the prevention of peritendinous adhesion formation. The strength of the repair was not affected by these cytokines and 5-FU.

Experimental study of tendon sheath repair via decellularized amnion to prevent tendon adhesion

The adhesion of tendon and surrounding tissue is the most common complication after repairing an injured tendon. The injured flexor tendons in zone II are frequently accompanied by tendon sheath defects, which lead to poor recovery. A variety of biological and non-biological materials have been recently used for repair or as substitute for tendon sheaths to prevent tendon adhesion. However, non-biological materials, such as polyethylene films, have been used to prevent tendon adhesions by mechanical isolation. The possibility of tendon necrosis and permanent foreign body remains due to the lack of permeability and the obstruction of nutrient infiltration. The natural macromolecule amniotic membrane derived from organisms is a semi-permeable membrane with the following characteristics: smooth; without vascular, nerve, and lymphatic; and rich in matrix, cytokines, enzymes, and other active ingredients. The unique structure of this membrane makes it an ideal biomaterial. In the experiment in Henry chicken, the model of tendon sheath defect and the flexor digitorum tendon in zone II was established and randomly divided into control group, medical membrane group, and decellularized amniotic membrane group. Samples were obtained at the 2nd, 4th, 8th, and 12th week after operation. General, histological, and biomechanical tests were performed to investigate the preventive effect of repaired tendon sheath by decallularized amniotic membrane. Experimental results showed the following: the amniotic membrane group and the medical membrane group had mild inflammatory reaction and tissue edema, and nearly no adhesion was observed in the surrounding tissue; the fibroblast-like cells were distributed in layers under the light microscope; the amniotic membrane group was denser than the medical membrane group cells, and numerous fibroblasts were disorganized in the control group. Biomechanical measurements showed that the sliding distance of tendon, the total flexion angle of the toes, and the tendon maximum tensile breaking strength at the early postoperative were significantly better than in the control group. Through this experiment, the amniotic membrane, as a natural biological substitute material in the construction of tendon sheath, can effectively inhibit exogenous healing and promote endogenous healing to prevent tendon adhesion.

Polymer materials for prevention of postoperative adhesion

Postoperative adhesion (POA) is a common complication that often occurs after a variety of surgeries, such as plastic surgery, repair operations of abdominal, pelvic, and tendon, and so forth. Moreover, POA leads to chronic abdominal pain, secondary infertility in women, intestinal obstruction, and other severe complications, which significantly reduce the life quality of patients. In order to prevent the formation of POA, a number of strategies have been developed, among which an emerging method is physical barriers consisting of polymer materials. This review highlights the most commonly used natural and synthetic polymer materials in anti-adhesion physical barriers. The specific features of polymer materials are analyzed and compared, and the possible prospect is also predicted.

STATEMENT OF SIGNIFICANCE

Postoperative adhesion (POA) is a serious complication accompanied with various surgeries. Polymer material-based physical barriers have attracted a large amount of attention in POA prevention. The polymer barriers can effectively avoid the formation of fibrous tissues among normal organs by reducing the interconnection of injured tissues. In this review, specific features of the natural and synthetic polymer materials for application in POA prevention were presented, and the possible prospects were predicted. All in all, our work can provide inspiration for researchers to choose proper polymer materials for preclinical and even clinical anti-adhesion studies.

Local administration of Trolox, a vitamin E analog, reduced tendon adhesion in a chicken model of flexor digitorum profundus tendon injury

Background

Hand flexor tendon injuries are compromised with tendon adhesion. Tendon adhesion forms between flexor tendon and tendon sheath, reduces the range of motion of fingers, and affects their function. Oxidative stress is increased in flexor tendon after injury and might play a role in tendon adhesion formation. Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid), a water-soluble analog of vitamin E, is antioxidative. Trolox reduced oxidative stress and the expression of fibrotic cytokines in the bile gut ligation animal model. Vitamin C and Trolox are strong antioxidants, but they might also have prooxidant properties. The prooxidant properties of vitamin C and Trolox are different. In this study, our aim was to determine the effect of Trolox in reducing tendon adhesion formation.

Methods

Flexor digitorum profundus tendon injury was induced in 54 Kai-Mei Chicken according to a well-established protocol. After wound closure, an injection of 50 μL saline, 10mM Trolox, or 100mM Trolox was administered into the wound area. At 2 weeks or 6 weeks after the surgery, chicken feet were harvested for gliding test, high-resolution ultrasound measurement on a fibrotic area, and histology.

Results

At Week 2 after the surgery, Trolox has no effect on the flexion angle and gliding resistance, whereas a significant improvement was observed in the flexion angle and gliding resistance in the Trolox-treated groups at Week 6. However, no dose response was observed. In the ultrasound measurement, there was no significant difference in the fibrotic mass in the Trolox-treated group as compared to the saline group at Week 2. At Week 6, fibrotic mass was significantly reduced in both Trolox-treated groups. From the histological examination, the Trolox-treated groups presented a higher cellularity at Week 2 as compared to the saline group, and reduced fibrosis and adhesion at Week 6.

Conclusion

Our results suggest that local administration of Trolox can reduce tendon adhesion, and a higher dose of Trolox did not have negative effects.

Clinical Significance

Trolox solution might be feasible to reduce tendon adhesion via intraoperative injection at the wound area during tendon repair.

The effect of a collagen-elastin matrix on adhesion formation after flexor tendon repair in a rabbit model

PURPOSE

The outcome of flexor tendon surgery is negatively affected by the formation of adhesions which can occur during the healing of the tendon repair. In this experimental study, we sought to prevent adhesion formation by wrapping a collagen-elastin scaffold around the repaired tendon segment.

METHODS

In 28 rabbit hind legs, the flexor tendons of the third and fourth digits were cut and then repaired using a two-strand suture technique on the fourth digit and a four-strand technique on the third digit. Rabbits were randomly assigned to study and control groups. In the control group, the operation ended by closing the tendon sheath and the skin. In the study group, a collagen-elastin scaffold was wrapped around the repaired tendon segment in both digits. After 3 and 8 weeks, the tendons were harvested and processed histologically. The range of motion of the digits and the gap formation between the repaired tendon ends were measured. The formation of adhesions, infiltration of leucocytes and extracellular inflammatory response were quantified.

RESULTS

At the time of tendon harvesting, all joints of the operated toes showed free range of motion. Four-strand core sutures lead to significantly less diastasis between the repaired tendon ends than two-strand core suture repairs. The collagen-elastin scaffold leads to greater gapping after 3 weeks compared to the controls treated without the matrix. Within the tendons treated with the collagen-elastin matrix, a significant boost of cellular and extracellular inflammation could be stated after 3 weeks which was reflected by a higher level of CAE positive cells and more formation of myofibroblasts in the αSMA stain in the study group. The inflammatory response subsided gradually and significantly until the late stage of the study. Both the cellular and extracellular inflammatory response was emphasized with the amount of material used for the repair.

CONCLUSION

The use of a collagen-elastin matrix cannot be advised for the prevention of adhesion formation in flexor tendon surgery, because it enhances both cellular and extracellular inflammation. Four-strand core sutures lead to less gapping than two-strand core sutures, but at the same time, the cellular and extracellular inflammatory response is more pronounced.

Implantation of a denaturated cellulose adhesion barrier after plate osteosynthesis of finger proximal phalangeal fractures: results of a randomized controlled trial

Adhesions after osteosynthesis of finger proximal phalangeal fractures often cause stiffness. To minimize adhesions, the use of an adhesion barrier has been proposed. The results until now have not been convincing. The aim of this prospective randomized trial was to evaluate the use of an adhesion barrier. The trial included any isolated, closed proximal phalangeal fracture needing plate osteosynthesis. The patients were randomized into two groups: with or without application of the adhesion barrier. The outcomes we measured were finger ranges of motion and DASH score at 6 weeks and 6 months post-operatively. A total of 42 patients (42 fingers) entered the study; 37 completed the study. The key baseline characteristics were comparable. At 6 weeks there was a trend favouring the adhesion barrier that disappeared at 6 months. Overall the results do not support the use of this device.

Evaluation of 4DryField® PH as Adhesion Prevention Barrier Tested in an Optimized Adhesion Model in Rats

BACKGROUND

Adhesions due to pelvic/abdominal surgery are a common serious pathology possibly entailing severe complications. This study investigates the adhesion prevention capability of the novel starch-based agent 4DryField® PH, which together with saline solution forms a barrier gel. Herein, an optimized adhesion model (OPAM) inducing severe adhesions/agglutinations with high reproducibility was used.

METHODS

In 19 Lewis rats, a 1 × 2 cm abdominal wall defect was created, the peritoneum of the neighboring cecum was abraded, and both injured areas were approximated by suture. Rats were randomized to control (n = 10) or 4DryField PH treatment (n = 9) groups. Another 8 rats had sham surgery for safety assessment of 4DryField PH. At day 7, the quantity and quality of adhesions were assessed macro-/microscopically and evaluated statistically.

RESULTS

4DryField PH treatment significantly reduced the incidence and severity of adhesions as verified by significantly improved adhesion scorings (0.4 vs. 4.5; 1.1 vs. 9). Histology revealed reconstitution of the cecum and abdominal wall including regeneration of the visceral/parietal peritoneum. In sham-operated rats, 4DryField PH did not induce adhesion formation.

CONCLUSIONS

4DryField PH gel was highly effective in preventing adhesions. Histologically, the injured cecum and abdominal wall regenerated well in the presence of 4DryField PH. Considering the severity of OPAM trauma, the potential of 4DryField PH to prevent adhesions can be rated excellent.

Biomechanical and Macroscopic Evaluations of the Effects of 5-Fluorouracil on Partially Divided Flexor Tendon Injuries in Rabbits

Background:

The main goals of flexor tendon surgery are to restore digital motion by providing tendon healing and to preserve tendon gliding. Our purpose was to investigate the effects of 5-fluorouracil (5-FU) on tendon adhesions in partially divided profundus flexor tendons (flexor digitorum profundus [FDPs]) following surgical repair and in partially divided FDPs without surgical repair, and to compare the results of the repair versus the nonrepair of zone two injuries via macroscopic and biomechanical evaluations of tendon adhesions.

Methods:

We used 32 adult male European rabbits (Oryctolagus cunniculus) weighing from 2.5 to 3.5 kg. The study was performed on the deep flexor tendons of the second and third digits of the right hind paws of the rabbits; thus, a total of 64 tendons were examined in this study.

Results:

Based on the results achieved in our experimental study, the load (N) significantly increased in subgroup 1a in which the tendons were surgically repaired and were not treated with 5-FU compared with subgroup 2a in which tendons were surgically repaired and treated with 5-FU.

Conclusions:

The load (N) significantly increased in subgroup 1a in which the tendons were surgically repaired and were not treated with 5-FU compared to subgroup 2a in which the tendons were surgically repaired and treated with 5-FU. Therefore, these results revealed a decrease in adhesion formation in the subgroup that was treated with 5-FU due to increased resistance to tendon adhesions during their excursion through the tendon sheath, which in this case required greater traction force.

History and performance of implant materials applied as peritendinous antiadhesives

Peritendinous fibrotic adhesions after tendon surgery are still a problem up-to-date. Approaches to overcome or at least minimize adhesion formation include implantation of barrier materials, application of lubricants or combinations of materials and functionalized drugs that are controllably released and support the healing tendon to glide and achieve the full range of motion after regeneration. Although a huge amount of different materials have been experimentally tested, the optimal strategy with respect to material and method has not yet been determined. In this review, we present a historical overview of physical barriers as well as liquid agents that have been used in order to prevent peritendinous adhesion formation. The materials are divided according to their first publication into two time frames; before and after 1980. There is no claim to include all materials tested neither will the "best" material be chosen; however, we present several materials that were experimentally tested in different animal trials as well as in clinical trials in contrast to other materials that were only tested once and disappeared from the assortment of anti-adhesives; which as such is a valuable information about its applicability for this purpose.

Gliding resistance and modifications of gliding surface of tendon: clinical perspectives

The smooth gliding of the normal human digital flexor is maintained by synovial fluid lubrication and lubricants bound to the tendon surface. This system can be disrupted by degenerative conditions such as trigger finger, or by trauma. The resistance to tendon gliding after surgical repair of the lacerated digital flexor tendon relates to location of suture knots, exposure of suture materials, and type of surgical repair and materials. Restoration of a functioning gliding surface after injury can be helped by using low-friction, high-strength suture designs, therapy that enables gliding, and the addition of lubricants to the tendon surface.

Improved postoperative outcome of segmental fasciectomy in Dupuytren disease by insertion of an absorbable cellulose implant

In this case-control prospective study, we investigated if we could improve the surgical outcome of interrupting strands in Dupuytren disease by creating a blocking effect with an absorbable cellulose implant, a known absorbable adhesion barrier. We studied 33 operations in 29 patients who had the potential for recurrent disease. The cellulose was implanted in the first 15 patients. An intraindividual control was added in 4 patients, who were given the implant in 1 of 2 operated hands. Goniometric evolution was monitored on digital photography, and satisfaction was measured on a visual analogue scale (VAS) with a preliminary one year follow-up. With the implant the postoperative range of movement improved significantly (by 33%) and remained unchanged after three months to a one year follow-up. The VAS for satisfaction also improved. We conclude that cellulose implants may improve the outcome of segmental fasciectomy in Dupuytren disease by achieving a better extension of fingers and a higher patients' satisfaction.

Adhesion reduction after knee surgery in a rat model by mitomycin C

The purpose of this study was to investigate the effect of Mitomycin C on reduction in intra-articular fibrotic adhesion formation after knee surgery. Twenty female Wistar Albino rats were divided into two equal study groups. After skin incision, the right knees of animals were opened through a medial parapatellar approach, and the medial and lateral sides of the femoral condyle were exposed. A partial capsulotomy and synovectomy were performed. In group I, Mitomycin C was applied in the articular cavity of rats after hemostasis. An identical volume of sterile normal saline was applied in group II, which served as controls. All rats received weekly (6 weeks) intra-articular both Mitomycin C and saline starting from the day of operation. Animals were killed at 45 days after surgery. The presence and severity of osteo-capsular adhesion was assessed with both macroscopic and microscopic adhesion scoring systems. Results of macroscopic observations showed a significant reduction in both incidence and severity of adhesions in group I compared to group II. Histologically, adhesions in group I were thinner with less collagenic fibers. Microscopic determination of adhesion formation was less in group I, and the difference between groups was statistically significant. Our results suggest that post-operative administration of Mitomycin C may be considered a promising preventive therapy for the reduction in fibro-adhesive scars and consequent stiffness after knee surgery.

Effect of mitomycin-C on post-operative adhesions in tendon surgery: an experimental study in rats

We investigated the effect of mitomycin-C on the reduction of the formation of peritendinous fibrous adhesions after tendon repair. In 20 Wistar albino rats the tendo Achillis was cut and repaired using a modified Kessler technique. The rats were divided into two equal groups. In group 1, an injection of mitomycin-C was placed between the tendon and skin of the right leg. In group 2, an identical volume of sterile normal saline was injected on the left side in a similar fashion. All the rats received mitomycin-C or saline for four weeks starting from the day of operation. The animals were killed after 30 days. The formation of peritendinous fibrous tissue, the inflammatory reaction and tendon healing were evaluated. The tensile strength of the repaired tendons was measured biomechanically. Microscopic evidence of the formation of adhesions and inflammation was less in group 1. There was no significant difference in the tensile load required to rupture the repaired tendons in the two groups. Mitomycin-C may therefore provide a simple and inexpensive means of preventing of post-operative adhesions.

The effect of seprafilm on adhesion formation and tendon healing after flexor tendon repair in chicken

Adhesion of the tendon, which can occur during healing of tendon repair, is negatively affected by the outcome of surgery. In this experimental study, we sought to prevent adhesion of the tendon, and determined the mechanical stiffness of repair tissue by wrapping sodium hyaluronate and carboxymethylcellulose (Seprafilm; Genzyme, Cambridge, Massachusetts) around the repaired tendon segments. The study group comprised 2 groups of 20 chickens. In group I, the right gastrocnemius tendons of the chickens were cut smoothly, and after tendon and sheath repair, the skin was sutured. In group II, the right gastrocnemius tendons of the chickens were cut, the tendons were repaired, and before skin closure, Seprafilm was wrapped around the repaired tendon segments. Plastic splints were used for holding the chickens' ankles in a neutral position, and they were allowed weight bearing for 8 weeks. In group II, anatomic space between the tendon-sheath and tendon was clear and the tendon-sheath complex was sliding easily around the repaired tendon segment, and this complex was more functional both biomechanically and histologically. Also, the Seprafilm-applied tendons (group II) were observed to be biomechanically more resistant to the tensile forces in group I. Seprafilm is an easily applied interpositional material that can be used safely to prevent adhesion during the tendon healing process.

Achilles tendon recurrent rupture following surgical repair: report on two cases

BACKGROUND

Rerupture is a main complication in Achilles tendon rupture surgery, with an incidence of 2-8%. Although wound break-down and rerupture are well known complications, spontaneous open rerupture has not been previously reported to the authors' knowledge.

METHODS

We report on two cases of open rerupture of Achilles tendon following augmented repair, through a transverse wound perpendicular to the primary incision line. Reruptures occurred 80 and 54 days after primary repair.

RESULTS AND CONCLUSIONS

After surgical repair long term follow-up results are good in both cases. This complication could be related to subtotal closure of the paratenon due to the bulk of the augmented repair and to an inadequate and a too extended period of postoperative ankle immobilization.