Reconstruction of a body wall defect using diaphragm lateralisation and advancement, latissimus dorsi, and internal and external abdominal oblique muscle flaps in a cat

Abstract

Case summary: A cat aged 12 years and 7 months was referred to a multidisciplinary hospital for investigation of feline injection site sarcoma (FISS) on the left thoracolumbar region. A CT examination of the mass revealed a multi-lobulated mass affecting the body wall, extending from the level of lumbar vertebrae L2 to L4. The mass was excised with 5 cm lateral margins, including resection of the 13th left rib, the caudal edge of the latissimus dorsi (LD) muscle, full-thickness abdominal wall and sections of the lumbar epaxial muscles. To reconstruct the defect, a combination of muscle flaps was used. This included diaphragmatic advancement and lateralisation, rotation of the LD, and creation of transposition flaps from the internal abdominal oblique and external abdominal oblique muscles, ensuring closure without tension. Skin closure required mobilising an inguinal flank fold flap. The cat was discharged from hospital 3 days postoperatively. Histopathology confirmed a diagnosis of FISS with clean wide margins. A gradual return to normal activity and complete healing of the surgical site was reported on follow-up, with one minor complication related to the skin flap (bruising at the base of the inguinal flank fold flap).

Relevance and novel information: This report describes the use of the aforementioned combination of muscle flaps to close a major abdominal wall defect in a cat with an excellent outcome. Practitioners can consider this technique when planning tissue reconstruction after FISS resection.

Keywords: FISS; Injection site sarcoma; body wall defect; muscle flap; reconstruction.

Figure 1

Multi-planar reconstruction CT images of the abdomen and thorax, showing the mass in the left dorsolateral abdominal wall, compatible with a feline injection site sarcoma (red arrow). Images are post-contrast and displayed in a soft tissue window: (a) sagittal, (b) transverse and (c) frontal

Figure 2

(a) Feline injection site sarcoma (FISS) present on left flank with sterile surgical pen markings around palpable edges of mass (inner continuous line) and 5 cm lateral margins (outer dotted line). (b) Body wall defect after excision of the FISS with 5 cm lateral margins

Figure 3

(a) Abdominal wall defect after wide excision of the mass. The lumbar epaxial muscles (1) and remnants of the transversus abdominis (5) are dorsal to the defect. Stay sutures are placed on the latissimus dorsi (LD) (2) caudal edge of the diaphragm (4) and internal abdominal oblique (IAO) (3). (b) The IAO muscle flap (3) was sutured cranially to the free edge of the LD (2) and diaphragm, and dorsally to the transversus abdominis (5). Stay sutures are placed on the external abdominal oblique (EAO) (6) and ventral remnants of the IAO muscle. (c) The EAO muscle (6) was sutured dorsally to the IAO muscle (3) and cranially to the LD (2) and to the remnants of the IAO muscle. This allowed complete closure of the defect

Figure 4

Skin closure with transposition of an inguinal flank fold flap

Figure 5

Photographs submitted by the owner 16 days postoperatively

Figure 6

Photographs submitted by the owner 47 weeks postoperatively