The role of an adhesive (Histoacryl) in tendon repair

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.

Forces Transmitted Along Human Flexor Tendons During Passive and Active Movements of the Fingers

The in vivo forces in human digital flexor tendons were determined in 33 patients undergoing a carpal tunnel decompression surgery using a newly developed device. The tendons were tested in passive and active flexion, and flexing against resistance of up to 500 g. Forces in the range of 0.2 to 50 N were noted. Whilst the mean of these forces remained below the force normally required to dehisce a fresh modified Kessler repair, the range of values was such that we would only recommend early movement with great caution and under supervision.

Shear lag sutures: Improved suture repair through the use of adhesives

Suture materials and surgical knot tying techniques have improved dramatically since their first use over five millennia ago. However, the approach remains limited by the ability of the suture to transfer load to tissue at suture anchor points. Here, we predict that adhesive-coated sutures can improve mechanical load transfer beyond the range of performance of existing suture methods, thereby strengthening repairs and decreasing the risk of failure. The mechanical properties of suitable adhesives were identified using a shear lag model. Examination of the design space for an optimal adhesive demonstrated requirements for strong adhesion and low stiffness to maximize the strength of the adhesive-coated suture repair construct. To experimentally assess the model, we evaluated single strands of sutures coated with highly flexible cyanoacrylates (Loctite 4903 and 4902), cyanoacrylate (Loctite QuickTite Instant Adhesive Gel), rubber cement, rubber/gasket adhesive (1300 Scotch-Weld Neoprene High Performance Rubber & Gasket Adhesive), an albumin-glutaraldehyde adhesive (BioGlue), or poly(dopamine). As a clinically relevant proof-of-concept, cyanoacrylate-coated sutures were then used to perform a clinically relevant flexor digitorum tendon repair in cadaver tissue. The repair performed with adhesive-coated suture had significantly higher strength compared to the standard repair without adhesive. Notably, cyanoacrylate provides strong adhesion with high stiffness and brittle behavior, and is therefore not an ideal adhesive for enhancing suture repair. Nevertheless, the improvement in repair properties in a clinically relevant setting, even using a non-ideal adhesive, demonstrates the potential for the proposed approach to improve outcomes for treatments requiring suture fixation. Further study is necessary to develop a strongly adherent, compliant adhesive within the optimal design space described by the model.

Current state and use of biological adhesives in orthopedic surgery

Bone and tissue adhesives are common and beneficial supplements to standard methods of musculoskeletal tissue suture repair. Knowledge and development of biologically derived or inspired adhesives useful in orthopedic surgery are rapidly advancing. Recent literature demonstrates the increased adjunct or primary use of biological adhesives in the repair of musculoskeletal soft tissues, chondral fractures, and osteochondral fractures. Adhesives offer more benefits and enhancements to tissue healing than current fixation methods afford, including improved biocompatibility, resorbability, and non-immunogenicity. Further investigation is required to determine the extent of the role that these bioadhesives can play in orthopedic surgery. The largest group of biologically derived adhesives and sealants is fibrin sealants, which include first- and second-generation commercially available fibrin sealants, autologous fibrin sealants, and variants. Other groups include gelatin-resorcin aldehydes, protein-aldehyde systems, collagen-based adhesives, polysaccharide- based adhesives, mussel adhesive proteins, and various biologically inspired or biomimetic glues. Potential uses include applications in orthopedic-related blood conservation, arthroplasty, articular cartilage disorders, sports medicine, spine surgery, trauma, and tumors. The development of an adhesive with universal application is likely unfeasible, given the unique characteristics of various musculoskeletal tissues. However, the literature demonstrates the overall underuse of adhesives and indicates the rising probability of the development of a successful variety of bioadhesives for use in orthopedic surgery. As a result of reading this article, physicians should be able to: 1. Describe the difference between adhesives and sealants. 2. Recognize fibrin adhesives commonly used in practice today and identify other biological adhesives with rising potential. 3. Analyze how fibrin sealants work relative to fibrin and fibrinogen. 4. Identify anatomical areas and techniques in which fibrin sealants are used.

Factors influencing the tensile strength of repaired Achilles tendon: a biomechanical experiment study

BACKGROUND

Operative treatment has been advocated as the method of choice to repair Achilles tendon rupture as surgery results in reduced re-rupture rate and faster rehabilitation. Many surgical techniques have been introduced allowing for postoperative early motion of the ankle joint. However, it is currently very difficult for surgeons to determine the optimal treatment conditions for ruptured Achilles tendon with an increasing number of end-to-end suture methods, suture materials, and epitenon suture techniques.

METHODS

In the present biomechanical experiment study based on an orthogonal design, thirty-two New Zealand white rabbits received Achilles tendon tenotomy and subsequent operative treatment to repair the tendon employing four end-to-end suture methods, four suture materials, and four epitenon suture techniques. The tensile strength of the repaired Achilles tendon was investigated at four rehabilitation periods, and in comparison with the results of another sixteen rabbits with normal Achilles tendons.

FINDINGS

The end-to-end suture method contributed most to the final Achilles tendon tensile strength in addition to rehabilitation period, with the highest values occurring with the use of the parachute-like ("Pa" bone) suture method. The other two factors, namely, suture material and epitenon suture technique, had relatively little influence on the results.

INTERPRETATION

The parachute-like ("Pa" bone) surgical technique is superior to the other three end-to-end suture methods, with enhanced tensile strength of the repaired tendon. This method allows for postoperative early kinesitherapy of the ankle and knee joints. Therefore, this technique is highly recommended in clinical situations for treatment of ruptured Achilles tendon.

A device to measurein vivoforces in human flexor tendons during carpal tunnel operations

An apparatus has been designed to measure the in vivo forces transmitted along human hand flexor tendons during carpal tunnel release procedures. The tendon will be run through three hooks, the central one of which is attached to a load cell. The rationale is that once these forces are known this will aid in the design of repair techniques and rehabilitation regimens. As a first stage, an in vitro validation study is presented using cord subjected to varying forces to mimic an in vivo flexor tendon under varying conditions of use. Our results show that we can accurately and reproducibly measure the force in the cord.

The implantation of non-cell-based materials to prevent the recurrent disc herniation: an in vivo porcine model using quantitative discomanometry examination

Recurrent disc herniation is frequently observed due to leakage of nucleus pulposus through injured anulus fibrosus. There is no effective treatment to prevent recurrent disc herniation yet. In this study, we proposed to implant non-cell-based materials into the porcine disc to stimulate the growth of fibrous tissue and thereby increase the disc functional integrity. The disc herniation was simulated by anular punctures using the spinal needles. Four clinically used implantation materials, i.e., gelfoam, platinum coil, bone cement and tissue glue, were delivered into the discs via percutaneous spinal needles. Two months after the surgery, the swine were killed. The degree of disc integrity of intact, naturally healed and implanted discs, was examined by quantitative discomanometry apparatus. We found the disc injury could not recover after 2 months of healing, and the disc implantation affected the degree of disc integrity. The disc integrity of gelfoam-implanted discs was better than that of coil-, bone cement-, and glue-implanted discs. The implantation of non-cell-based material was proved to be a potentially clinically applicable method to recover the integrity of injured discs and to prevent recurrent disc herniation.

Histoacryl glue in meniscal repairs (a biomechanical study)

The purpose of this study was to investigate the biomechanical efficacy of Histoacryl (cyanoacrylate, N-asetil 2 butyl sistein) in meniscal tear repair. In our study, the primary stability of three different repair techniques in delaying the formation of a gap of 2 mm was investigated. A meniscal tear was repaired with two vertical sutures and Histoacryl in the first group; it was repaired only with Histoacryl in the second group, and with only two vertical sutures in the third group. Menisci were then placed in a tensile loading machine, and the primary stability of the repair zones was measured until a displacement of 2 mm occurred. Biomechanical force was significantly (P<0.05) high (112.0+/-17.20 N) in all groups when vertical suture and Histoacryl glue were used together during displacements of 0.5, 1.0, 1.5 and 2.0 mm. We believe that Histoacryl is superior to vertical sutures regarding gap delaying. It potentiates the effect of vertical suture strength, permits early motion and thus merits an in vivo study.

Cytotoxicity of cyanoacrylate adhesives to cultured tendon cells

The in vitro cytotoxicity of four cyanoacrylate adhesives was tested using cultures of cells derived from human tendons. All four were found to be cytotoxic, even at concentrations as low as 1.7%, over the experimental period of up to 18 weeks. This study shows that such adhesives in their present state may not be suitable for re-joining cut tendons as their initial and long-term toxicity may hinder the slow healing process of tendons.

[An experimental study of a cyanoacrylate biological adhesive in view of its use in the fixation of various fractures of the fingers]

Following certain interesting results reported in publications by researchers from the nineteen-sixties up to the present time, we decided to experiment a particular adhesive with high adhesive properties: this is composed of monomers of alpha-cyanoacrylate éthyl-2-alpha-cyanoacrylate. For this end, experiments were performed on 15 adult chickens, aged around 4 months, weighing 2 kg, divided into 5 groups of 3 chickens each. In each chicken, a rectangular bone fragment from the proximal-middle third of the tibia was prepared, completely separated, and then subsequently re-positioned and fixed with the adhesive plus collagen. At pre-established intervals (7, 14, 21, 30 and 60 days), each group of chickens was examined by x-rays and then killed, so that the particular anatomical part under examination could be studied both microscopically and macroscopically. The aim of these experiments was to evaluate the ability of cyanoacrylate adhesive to ensure setting of small bone-fragments that would otherwise be unstable. The results obtained showed the following: good stability of the bone fragment; good bone consolidation; absence of foreign body reactions. The positive nature of these results leads us to propose the use of this adhesive in hand surgery. Nevertheless, duty requires that further experiments be performed in order to acquire even greater guarantees for the positive results obtained.