Effects of Cyanoacrylate in Rabbits with Induced Achilles Tendon Rupture.

BACKGROUND In this study, we aimed to investigate the effects of N-butyl-2-cyanoacrylate (cyanoacrylate) on the biomechanical and histopathological aspects of tendon healing in a rabbit model of Achilles tendon injury. MATERIAL AND METHODS In total, 36 rabbits were randomized to experimental (cyanoacrylate) and control groups (n=36 tendons in each group). A simple suture was used in the control group and a simple suture plus cyanoacrylate was used in the experimental group. Nine rabbits from each group were euthanized at week 4 and week 6 after surgery for histopathological and biomechanical testing. RESULTS Granulation tissue formation was significantly greater in the experimental group in week 4 and week 6 than in the control group. Foreign body giant cell formation was significantly higher in the experimental group in week 4 and week 6. The maximum rupture force was significantly higher in the experimental group in week 4 and week 6 than in the control group. Elasticity and stiffness were comparable between groups in week 4; however, stiffness, but not elasticity, was significantly higher in the experimental group in week 6. CONCLUSIONS In the short term, cyanoacrylate enhanced tendon endurance in both a histopathological and biomechanical manner. We conclude that the early initiation of rehabilitation in patients may be safe in cases of cyanoacrylate use for surgical repair of tendon injury.

The effect of tissue surface modification with collagenase and addition of TGF-ß3 on the healing potential of meniscal tears repaired with tissue glues in vitro.

The aim of the current in vitro study was to investigate if tissue surface modification with collagenase and addition of the TGF-ß3 can increase the number of cells present in meniscus tears repaired with the use of newly developed tissue adhesives based on isocyanate-terminated block copolymers. Cylindrical explants were harvested from the inner part of bovine menisci. To simulate a full-thickness tear, the central core of the explants was removed and glued back into the defect, with or without incubation in collagenase solution prior to gluing. The repair constructs were then cultured with or without addition of TGF-ß3, and assessed for their histological appearance. The histological staining of the constructs confirmed that both developed adhesives were not cytotoxic. After 28 days, meniscus cells were present in direct contact with the glues. The addition of TGF-ß3 to the culture medium resulted in the presence of cells that formed a sheath inside the simulated tear and in increased cell numbers at the edges of annulus of the explants. In the group in which the tissue was incubated in collagenase and cultured in medium containing TGF-ß3, thicker layers of cells were observed. These results suggest that repairing the torn meniscus with tissue adhesives after pre-treatment of the tissue with collagenase and stimulation with TGF-ß3 is a very promising treatment method, especially when treating the inner avascular part of the meniscus. Nevertheless, longer-term in vitro and in vivo studies are needed to confirm the beneficial effects of this combination therapy.

Tendon healing: an overview of physiology, biology, and pathology of tendon healing and systematic review of state of the art in tendon bioengineering.

PURPOSE: Tendon injuries vary from acute rupture to chronic tendinopathy. For an optimal treatment of either condition, a profound knowledge is essential. Therefore, this article shall give an overview of physiology, biology, and pathology of tendon healing and state of the art in tendon bioengineering. METHODS: For a preferably comprehensive survey, the current literature listed in PubMed and published in English peer-reviewed journals (March 2013) was systematically reviewed for tendon healing and tendon bioengineering including cytokine modulation, autologous sources of growth factors, biomaterials, gene therapy, and cell-based therapy. No differentiation was made between clinical and preclinical in vitro investigations. RESULTS: Tendon healing happens in certain stadiums of inflammation, formation, and remodelling. An additional process of "collagen recycling" close to the healing site has been described recently. With increasing comprehension of physiology and pathology of tendon healing, several promising approaches in tendon bioengineering using growth factors, biomaterials, gene therapy, or cell-based therapy are described. However, only some of these are already used routinely in clinics. CONCLUSION: Strong and resistant tendons are crucial for a healthy musculoskeletal system. The new approaches in tendon bioengineering are promising to aid physiological tendon healing and thus resulting in a stronger and more resistant tendon after injury. The growing knowledge in this field will need to be further taken into clinical studies so that especially those patients with prolonged courses, revision surgery, or chronic tendinopathy and high-demanding patients, i.e., professional athletes would benefit. LEVEL OF EVIDENCE: II.

Sientra primary and revision augmentation rupture trending and analysis with magnetic resonance imaging.

BACKGROUND: Rupture of silicone gel breast implants is a rare occurrence but remains one of the key surgical concerns. The objective of this article was to provide visibility and information on trends for the impact that patient and surgical characteristics play in the occurrence of rupture. OBJECTIVES: Examine trends in surgical techniques to better understand the etiology of implant rupture. METHODS: Analysis was based on Sientra's prospective, open-label, U.S.-based clinical study of High-Strength Cohesive silicone breast implants. Patient and surgical characteristics were compared between ruptured and intact implants. RESULTS: The subset of data used for this analysis included 1792 implants in 935 primary and revision augmentation patients implanted by 31 plastic surgeons, with an average follow-up of 6.6 years. The results confirm that rupture remains a rare adverse event. Overall, the rupture prevalence for this study was 2.4%. Rupture prevalence was lower among textured devices (0.8%) compared to smooth devices (3.8%). The prevalence of rupture was 7.8% among devices placed with a transaxillary incision site compared to 1.6% and 3.0% when placed with an inframammary or periareolar incision site, respectively. Rupture was reported in 5.5% of the devices that received steroid pocket irrigation, compared to 1.8% of the devices that did not. CONCLUSIONS: Although ruptures in the Sientra study with the High-Strength Cohesive silicone gel implants were an uncommon occurrence, the authors were able to identify strong trends for the association of certain surgical factors and characteristics. The results show among other factors that an inframammary approach and a textured device were found to be protective against rupture. LEVEL OF EVIDENCE: 2 Therapeutic.

Regeneration of rotator cuff tear using electrospun poly(d,l-Lactide-Co-Glycolide) scaffolds in a rabbit model.

PURPOSE: The purpose of this study was to evaluate an application of poly(d,l-lactide-co-glycolide) (PLG) scaffold created by electrospinning in a rabbit rotator cuff defect model. METHODS: Forty-two Japanese white rabbits were used in this study. Defects of the infraspinatus tendon were created, and the PLG scaffolds were implanted. Contralateral infraspinatus tendons were reattached without creating defects. Histologic analyses were performed 4, 8, and 16 weeks after the operation, and mechanical evaluations were performed 0, 4, 8, and 16 weeks after the operation. RESULTS: Scaffold fibers remained without dissolution and spindle-shaped cells were observed inside of the scaffold at 4 weeks postoperatively. At 8 weeks, the PLG scaffold had dissolved and bone formation was observed at the scaffold-bone interface. At 16 weeks, the scaffold-bone interface matured and expression of type II collagen was observed. A statistical difference in ultimate failure load was not seen between the scaffold group and reattachment group or normal tendon after 8 weeks postoperatively. The stiffness in the scaffold group was not significantly different from that in the reattachment group at each time point. However, it was significantly weaker than normal tendon at each time point. CONCLUSIONS: Transplantation of cell-free PLG scaffold showed cell migration and type II collagen and proteoglycan expression at the scaffold-bone junction by 16 weeks postoperatively with a sufficient ultimate failure load in a rabbit rotator cuff defect model. CLINICAL RELEVANCE: The PLG scaffold could be applied to bridge rotator cuff defects. The results showed that bridging with scaffold can be equivalent to reattachment.

Possibilities and limitations of electrospun chitosan-coated polycaprolactone grafts for rotator cuff tear repair.

Acute and chronic rotator cuff tears remain challenging for therapy. A wide range of therapeutic approaches were developed but re-tears and postoperative complications occur regularly. Especially in elderly people, the natural regeneration processes are decelerated, and graft materials are often necessary to stabilize the tendon-to-bone attachment and to improve the healing process. We here investigated in a small animal model a newly developed electrospun polycaprolactone fiber implant coated with a chitosan-polycaprolactone graft copolymer and compared these implants biomechanically and histologically with either a commercially available porous polyurethane implant (Biomerix 3D Scaffold) or suture-fixed tendons. Fifty-one rats were divided into three groups of 17 animals each. In the first surgery, the left infraspinatus tendons of all rats were detached, and the animals recovered for 4 weeks. In the second surgery, the tendons were fixed with suture material only (suture-fixed group; n = 17), whereas in the two experimental groups, the tendons were fixed with suture material and the polyurethane implant (Biomerix scaffold group; n = 17) or the modified electrospun polycaprolactone fiber implant (CS-g-PCL scaffold group; n=17), respectively. The unaffected right infraspinatus tendons were used as native controls. After a recovery of 8 weeks, all animals were clinically inconspicuous. In 12 animals of each group, repaired entheses were biomechanically tested for force at failure, stiffness, and modulus of elasticity, and in five animals, repaired entheses were analyzed histologically. Biomechanically, all parameters did not differ statistically significant between both implant groups, and the entheses failed typically at the surgical site. However, with respect to the force at failure, the median values of the two implant groups were smaller than the median value of the suture-fixed group. Histologically, the modified polycaprolactone fiber implant showed no acute inflammation processes, a good infiltration with cells, ingrowth of blood vessels and tendinous tissue, and a normal fibrous ensheathment. Further improvement of the implant material could be achieved by additional implementation of drug delivery systems. Therewith, the used CS-g-PCL fiber mat is a promising basic material to reach the goal of a clinically usable graft for rotator cuff tear repair.

In vitro comparison of human fibroblasts from intact and ruptured ACL for use in tissue engineering.

The present study compares fibroblasts extracted from intact and ruptured human anterior cruciate ligaments (ACL) for creation of a tissue engineered ACL-construct, made of porcine small intestinal submucosal extracellular matrix (SIS-ECM) seeded with these ACL cells. The comparison is based on histological, immunohistochemical and RT-PCR analyses. Differences were observed between cells in a ruptured ACL (rACL) and cells in an intact ACL (iACL), particularly with regard to the expression of integrin subunits and smooth muscle actin (SMA). Despite these differences in the cell source, both cell populations behaved similarly when seeded on an SIS-ECM scaffold, with similar cell morphology, connective tissue organization and composition, SMA and integrin expression. This study shows the usefulness of naturally occurring scaffolds such as SIS-ECM for the study of cell behaviour in vitro, and illustrates the possibility to use autologous cells extracted from ruptured ACL biopsies as a source for tissue engineered ACL constructs.

[DIPROSPAN, LONGIDAZA AND THEIR COMBINED ACTION AGAINST FIBROSIS CAUSED BY MECHANICAL INJURY OF THE INTERVERTEBRAL DISCS IN RATS].

The formation of connective tissue changes in the spinal canal of rats, caused by the method of intervertebral disc ruptures, in association with a mixture of epidural injection of longidaza and diprospan has been researched. Simultaneous injection of hialuronidase and betamethasone in composition of diprospan and longidaza, revealed a high synergistic effect and anti-fibrotic activity. Combined antifibrosis action of these two drugs is stronger than the sum of the actions of the two drugs in their separate use. Reducion of the maximum thickness of the fibrous layer was 49%, compared with the reference value and reduction of the total area of the fibrous formation was 46%. In our opinion, due to anti-inflammatory effects and the ability to reduce epidural scar adhesion, this complex is promising for its therapeutic use in treatment of spinal epidural fibrosis.

Synthesis, characterization and histomorphometric analysis of cellular response to a new elastic DegraPol® polymer for rabbit Achilles tendon rupture repair.

Tendon rupture repair is a surgical field where improvements are still required due to problems such as repeat ruptures, adhesion formation and joint stiffness. In the current study, a reversibly expandable and contractible electrospun tube based on a biocompatible and biodegradable polymer was implanted around a transected and conventionally sutured rabbit Achilles tendon. The material used was DegraPol® (DP), a polyester urethane. To make DP softer, more elastic and surgeon-friendly, the synthesis protocol was slightly modified. Material properties of conventional and new DP film electrospun meshes are presented. At 12 weeks post-surgery, tenocyte and tenoblast density, nuclei and width, collagen fibre structure and inflammation levels were analyzed histomorphometrically. Additionally, a comprehensive histological scoring system by Stoll et al. (2011) was used to compare healing outcomes. Results showed that there were no adverse reactions of the tendon tissue following the implant. No differences were found whether the DP tube was applied or not for both traditional and new DP materials. As a result, the new DP material was shown to be an excellent carrier for delivery of growth factors, stem cells and other agents responsible for tendon healing.

The value of clinical examination versus magnetic resonance imaging in the diagnosis of meniscal tears and anterior cruciate ligament rupture.

PURPOSE: The purpose of this study was to compare the accuracy of clinical examination versus magnetic resonance imaging (MRI) in diagnosing meniscal and anterior cruciate ligament (ACL) pathology. TYPE OF STUDY: Prospective, longitudinal study. METHODS: Between August 2001 and December 2001, we prospectively evaluated 50 consecutive patients (37 male, 13 female) with 65 pathologies of medial meniscal tears, lateral meniscal tears, and/or ACL rupture. The average preoperative period for the patients was 5 weeks (range, 5 days to 5 months) and their mean age was 22 years (range, 12 to 42 years). After initial clinical examination, the same sports medicine fellowship-trained orthopaedic surgeon (10-year practice profile of 100% sports medicine) evaluated the MRI of the patients and performed their arthroscopic procedure. Accuracy, sensitivity, specificity, and positive and negative predictive values were calculated comparing clinical examination, MRI, and arthroscopic evaluation. RESULTS: There was no statistical difference between MRI or clinical examination in diagnosing medial or lateral meniscal tears or ACL tears ( P >.05). The accuracy of the clinical examination and MRI evaluation was equal for diagnosing meniscal tears and ACL ruptures. CONCLUSIONS: A well-trained qualified surgeon can safely rely on clinical examination for diagnosing meniscal and ACL injuries. Clinical examination is at least as accurate as MRI in the skilled orthopaedic surgeon's hand. MRI should be reserved for more complicated and confusing cases. The routine ordering of an MRI scan of the knee before examination by a well-trained orthopaedic surgeon is not recommended. LEVEL OF EVIDENCE: Level II, diagnostic.

MR evaluation of breast implants.

This article describes the rationale and indications for breast implant-related magnetic resonance (MR) imaging, alone or in combination with breast cancer-related MR imaging. Basic silicone chemistry, implant styles, and normal appearances of breast implants are described. The various presentations of breast implant rupture are described, and a 4-point staging scheme for intracapsular rupture is reviewed. Finally, a discussion of what the reviewing physician needs to know is presented, both before breast implant MR examinations are requested and afterward, when results are reported.

Prevention of peritendinous adhesions using an electrospun DegraPol polymer tube: a histological, ultrasonographic, and biomechanical study in rabbits.

PURPOSE: One of the great challenges in surgical tendon rupture repair is to minimize peritendinous adhesions. In order to reduce adhesion formation, a physical barrier was applied to a sutured rabbit Achilles tendon, with two different immobilization protocols used postoperatively. METHODS: Thirty New Zealand white rabbits received a laceration on the Achilles tendon, sutured with a 4-strand Becker suture, and half of the rabbits got a DegraPol tube at the repair site. While fifteen rabbits had their treated hind leg in a 180° stretched position during 6 weeks (adhesion provoking immobilization), the other fifteen rabbits were recasted with a 150° position after 3 weeks (adhesion inhibiting immobilization). Adhesion extent was analysed macroscopically, via ultrasound and histology. Inflammation was determined histologically. Biomechanical properties were analysed. RESULTS: Application of a DegraPol tube reduced adhesion formation by approximately 20%--independently of the immobilization protocol. Biomechanical properties of extracted specimen were not affected by the tube application. There was no serious inflammatory reaction towards the implant material. CONCLUSIONS: Implantation of a DegraPol tube tightly set around a sutured tendon acts as a beneficial physical barrier and prevents adhesion formation significantly--without affecting the tendon healing process.

Cellular response of healing tissue to DegraPol tube implantation in rabbit Achilles tendon rupture repair: an in vivo histomorphometric study.

In tendon rupture repair, improvements such as higher primary repair strength, anti-adhesion and accelerated healing are needed. We developed a potential carrier system of an electrospun DegraPol tube, which was tightly implanted around a transected and conventionally sutured rabbit Achilles tendon. Histomorphometric analysis of the tendon tissue 12 weeks postoperation showed that the tenocyte density, tenocyte morphology and number of inflammation zones were statistically equivalent, whether or not DegraPol tube was implanted; only the collagen fibres were slightly less parallelly orientated in the tube-treated case. Comparison of rabbits that were operated on both hind legs with ones that were operated on only one hind leg showed that there were significantly more inflammation zones in the two-leg cases compared to the one-leg cases, while the implantation of a DegraPol tube had no such adverse effects. These findings are a prerequisite for using DegraPol tube as a carrier system for growth factors, cytokines or stem cells in order to accelerate the healing process of tendon tissue.

The diagnostic challenge of a tracheal tear with a double-lumen endobronchial tube: massive air leak developing from the mouth during mechanical ventilation.

The case of a 78 year-old woman who underwent a right lower lobectomy using a 35-French, left-sided, double-lumen endobronchial tube (DLET) is presented. Multiple adjustments were needed for the DLET's proper placement. At the end of surgery, sudden loss of tidal volume with a large air leak from the patient's mouth was noted. Fiberoptic bronchoscopic examination through the DLET was negative. Rupture of the tracheal cuff was suspected, and the DLET was replaced with a single-lumen tube. In the intensive care unit, the massive air leak from the mouth recurred during mechanical ventilation. Nasal fiberoptic bronchoscopic examination showed a longitudinal laceration of the membranous portion of the trachea extending from the subglottic area to the orifice of the right bronchus. Surgical repair of the tear was performed.

On the potential of a new IVUS elasticity modulus imaging approach for detecting vulnerable atherosclerotic coronary plaques: in vitro vessel phantom study.

Peak cap stress amplitude is recognized as a good indicator of vulnerable plaque (VP) rupture. However, such stress evaluation strongly relies on a precise, but still lacking, knowledge of the mechanical properties exhibited by the plaque components. As a first response to this limitation, our group recently developed, in a previous theoretical study, an original approach, called iMOD (imaging modulography), which reconstructs elasticity maps (or modulograms) of atheroma plaques from the estimation of strain fields. In the present in vitro experimental study, conducted on polyvinyl alcohol cryogel arterial phantoms, we investigate the benefit of coupling the iMOD procedure with the acquisition of intravascular ultrasound (IVUS) measurements for detection of VP. Our results show that the combined iMOD-IVUS strategy: (1) successfully detected and quantified soft inclusion contours with high positive predictive and sensitivity values of 89.7 ± 3.9% and 81.5 ± 8.8%, respectively, (2) estimated reasonably cap thicknesses larger than ∼300 µm, but underestimated thinner caps, and (3) quantified satisfactorily Young's modulus of hard medium (mean value of 109.7 ± 23.7 kPa instead of 145.4 ± 31.8 kPa), but overestimated the stiffness of soft inclusions (mean Young`s moduli of 31.4 ± 9.7 kPa instead of 17.6 ± 3.4 kPa). All together, these results demonstrate a promising benefit of the new iMOD-IVUS clinical imaging method for in vivo VP detection.

Bronchial rupture with a left-sided polyvinylchloride double-lumen tube.

Bronchial rupture after intubation with a double-lumen endobronchial tube has been infrequently reported. Overinflation of the bronchial cuff was speculated to be a frequent cause of the bronchial damage. We report the case of a 78-year-old woman with non-small cell carcinoma of the right upper lobe. Her trachea and left main-stem bronchus were intubated with a left-sided polyvinylchloride (PVC) double-lumen endobronchial tube (Broncho-Cath(R) 37 Fr, Mallinckrodth Medical, Athlone, Ireland). She underwent an uneventful right upper lobectomy. At the end of the resection, the surgeons noticed the herniating cuff from the ruptured left main-stem bronchus. Laceration was repaired. Subsequent course of the patient was uneventful: she developed neither bronchial leak nor mediastinitis. Ten days later the patients was discharged home in a satisfactory condition. Factors that seem to increase the risk of injury by a double-lumen tube are discussed.