Use of a semitendinosus myocutaneous flap for the coverage of hindlimb full-thickness skin defects in cats

Abstract

Background The management of feline hindlimb full-thickness skin defects is challenging. On the other hand, the use of a semitendinosus (ST) myocutaneous flap for their coverage has not been reported. Objectives To describe the ST flap and compare it with second intention healing for managing hindlimb full-thickness skin defects. Methods In 12 purpose-bred laboratory domestic short-haired cats, two wounds were made on each tibia. The wounds in group A (n = 12) were covered with ST flaps, and those in group B (n = 12) were left to heal by second intention. In both groups, clinical assessment scoring and planimetry were performed between one–30 d postoperatively. Computed tomography-angiography (CTA) was performed on days zero, 10, and 30, and histological examinations were performed on days zero and 14 and at 6 and 12 mon postoperatively. Results Statistically significant differences in the clinical assessment scores were observed between groups A and B on days 14 ( p = 0.046) and 21 ( p = 0.016). On the other hand, the time for complete healing was similar in the two groups. CTA revealed significant differences in the muscle width (day 0 compared to days 10 and 30 [ p = 0.001, p = 0.026, respectively], and days 10 to 30 [ p = 0.022]), ST muscle density, and the caliber of the distal caudal femoral artery and vein (day 0 compared to day 10 [ p < 0.001], and days 10 to 30 [ p < 0.001]). Histologically significant differences in inflammation, degeneration, edema, neovascularization, and fibrosis were observed on day 14 compared to zero and 6 mon, but no differences were found between the time interval of 6 and 12 mon. Conclusions An ST flap can be used effectively to manage hindlimb full-thickness skin defects.

Comparison of Two Surgical Techniques Based on the Semitendinosus Myocutaneous Flap in Cats

“…Pain was evaluated by using the Colorado State University Feline Acute Pain Scale [ 24 , 25 ] while cats were alert, once before and then after the bandage changing. Healing scores were calculated according to the criteria described in recent reports [ 18 ].…”

“…Digital images of the flaps and a computer software (AutoCAD, version 2018, Autodesk, San Rafael, CA, USA) were used for planimetry evaluation. Planimetry was used in order to measure flaps’ length, width (cm), the initial total flap area (cm 2 ) (skin flap surface on day 0), the final total flap area (cm 2 ) (percentage of skin flap area viable on day 30) and the percentage of flap necrosis on days 7, 14, 21 and 30, according to previous reports [ 18 , 26 , 27 , 28 ].…”

“…The following parameters were evaluated: ST muscle length and width (cm), the caliber of the proximal gluteal and distal caudal femoral artery and vein (mm) and the density of ST muscle (Hounsfield unit [HU] at 10 mm 2 ) at three different points (dP: proximal, dM: medial, and dD: distal) in three different phases (pre-contrast agent, arterial and venous phase) [ 18 ]. [ Figure 3 and supplementary figures (Figures S3 and S4 )].…”

“…On days 0 and 14, tissue samples were collected by using a 6 mm biopsy punch (Biopsy punch; Kruuse, Langeskov, Denmark). For day 0 sampling, the distal tip of each flap was chosen, whereas on day 14 specimens were collected from the medial part of the distal edge of each flap, preserving the flaps’ microcirculation [ 18 ]. Specimens of 1 cm in width by 2 cm in length were collected from the middle of the medial part of all flaps, including only the muscle parenchyma, on 6- and 12 months.…”

“…Changes in electromyography, morphology, and ultrasound in the ST of dogs after the muscle transfer for PH repair were reported in a study by Mortari [ 16 ]. The authors have recently published an article reporting the use of the ST myocutaneous flap as a reconstructive technique for the management of skin defects on the feline hindlimb, also comparing its healing time to the second intention healing of such wounds [ 18 ]. The SST as a muscle flap has been successfully used for the augmentation of the Achilles tendon repair [ 19 ] and also as a method for PH management in dogs [ 20 ].…”