Hyaluronic acid and synovial fluid in preventing adhesion formation after tenorrhaphy: An in vivo study on rabbit Achilles tendon / Ácido hialurônico e líquido sinovial na prevenção da formação de aderências após tenorrafia: Um estudo in vivo sobre o tendão de Aquiles de coelho

ABSTRACT: Peritendinous adhesions are a significant problem in tendon surgery. One of the most preferred methods for preventing adhesion formation is anti-adhesive applications. This study aimed to investigate the efficacy of natural synovial fluid as an alternative viscoelastic agent for preventing adhesion in the healing period compared to hyaluronic acid. Thirty adult New Zealand rabbits were used in the study to form three experimental models. In all groups, a rupture was induced in the Achilles tendons. Following tenorrhaphy, hyaluronic acid was applied in one group and synovial fluid in the other group for anti-adhesive purposes. In the control group, no viscoelastic application was made. Bandage was applied to the operated extremities for three weeks post-operatively. At the end of five weeks, euthanasia was performed on the animals using pentobarbital sodium. Surgical sites in all groups were macroscopically examined for healing status as well as the presence and extent of adhesions. Biomechanical tests and histopathological examinations were then performed on the tendons in all groups. Findings established once again the positive contribution of hyaluronic acid to preventing adhesion formation as well as to healing and tensile strength in tendon surgery. Although, we found that it is possible to use synovial fluid, which is a natural source of hyaluronic acid, as a viscoelastic material, it is not superior to commercial hyaluronic acid preparation.

RESUMO: Asderências peritendinares são um problema significativo na cirurgia tendínea. Um dos métodos mais empregados para evitar a formação de adesão são as aplicações anti-adesivas. Este estudo tem como objetivo investigar a eficácia do líquido sinovial natural como um agente viscoelástico alternativo para prevenir a adesão no período de cicatrização comparado ao ácido hialurônico. Trinta coelhos adultos da Nova Zelândia foram utilizados no estudo para formar três modelos experimentais. Em todos os grupos, uma ruptura foi induzida nos tendões de Aquiles. Após tenorrafia, o ácido hialurônico foi aplicado em um grupo e o líquido sinovial no outro grupo para fins anti-adesivos. No grupo controle, não foi feita qualquer aplicação viscoelástica. A bandagem foi aplicada às extremidades operadas por três semanas pós-operatório. No final de cinco semanas, a eutanásia foi realizada nos animais utilizando pentobarbital sódico. Os locais cirúrgicos em todos os grupos foram examinados macroscopicamente quanto ao estado de cura, bem como a presença e extensão das aderências. Testes biomecânicos e exames histopatológicos foram realizados nos tendões em todos os grupos. Os achados estabeleceram mais uma vez a contribuição positiva do ácido hialurônico para prevenir a formação de aderências, bem como para a cicatrização e resistência à tração na cirurgia do tendão. Embora se tenha constatado que é possível utilizar fluido sinovial, que é uma fonte natural de ácido hialurónico, como material viscoelástico, não é superior à preparação de ácido hialurónico comercial.

The healing effect of shark cartilage in rabbits after colonic anastomosis.

AIM: Shark cartilage has anti-inflammatory, analgesic, anti-angiogenic, anti-tumoral, and immunomodulatory properties. We studied the effect of shark cartilage on the healing of colonic anastomoses, which are among the gastrointestinal system anastomoses that most commonly cause leakage. MATERIAL OF STUDY: Rabbits were divided into two groups of seven as the study and control groups. A normal diet was given to both groups before and after right colonic anastomosis. Shark cartilage tablets were given orally to the study group for five days before and after the anastomosis. Bursting pressures, hydroxyproline levels and translocation of the intestinal flora in anastomosis region were evaluated on the 6th day by operating on both groups. RESULTS: Bursting pressure and hydroxproline levels were higher in the experimental group compared to the control group (p<0.05). An increase in connective tissue and vascularization without growth of microorganisms was observed in the experimental group on microbiological examination. CONCLUSIONS: Shark cartilage given orally to rabbits increased anastomotic healing and did not cause serious consequences such as bacterial translocation.

Repair of urethral defects using fascia lata autografts in dogs.

OBJECTIVE: To evaluate the feasibility of urethroplasty using a free fascia lata (FL) graft in the dog. STUDY DESIGN: In vivo experimental study. ANIMALS: Mixed-breed dogs (n=14). METHODS: Half of the circumference of the urethra, approximately 1.5 cm long, was excised in 14 male dogs to induce a urethral defect. FL (approximately 2 cm x 2 cm) harvested from the lateral thigh was sutured to the urethra using a 3-0 polyglactin 910 continuous pattern. Dogs were monitored daily for bladder distention and had urethral catheters until normal voiding was observed. On day 60, each dog had a positive contrast urethrogram, and then 8 dogs were euthanatized for gross and histologic examination. Six dogs were monitored for urologic problems for 6 months, and a positive contrast urethrogram was repeated. RESULTS: All dogs recovered successfully; 4 dogs had difficulty voiding for 2-3 days and urine was aspirated from these dogs every 3 hours until signs of painful urination disappeared. On positive contrast urethrograms, urethral anatomy was considered normal except in 4 dogs that had an irregular contour. Gross urethral examination confirmed an absence of ulceration, stricture, diverticula, or fistula formation, and the FL-lined graft survived in all dogs. No degenerative and reparative responses were observed. On histologic examination of the penile urethra, the lumen was intact, covered with transitional epithelium, and surrounded by corpus spongiosum with cavernous spaces and blood-filled vessels. CONCLUSIONS: Free FL grafts are incorporated satisfactorily and would appear to be useful for repairing urethral defects. CLINICAL RELEVANCE: FL grafts should be considered for repair of urethral defects in dogs.