BioSIS for Soft Palate Reconstruction in Dogs: A New Option After Oral Tumor Resection

Oral tumors in the caudal oral cavity present one of the more demanding surgical scenarios in small animal practice. The tumor is often large before the owner notices it, the anatomy is unforgiving, and the preferred treatment — wide excision with clear margins — regularly produces defects that are difficult to close without significant morbidity. A new case report published in the Journal of Small Animal Practice describes a technique that changes the closure calculus: using porcine small intestinal submucosa (BioSIS, Vetrix) to reconstruct a full-thickness palatal defect, with complete healing and no recurrence at 22 months.

This is the first reported use of BioSIS for palatal defect closure in a dog — and it opens a clinically meaningful door for surgeons managing oral neoplasia where traditional flap techniques are declined or unavailable.

The Problem With Palatal Defect Closure

Malignant melanoma is the most common malignant oral tumor in dogs, accounting for 30 to 40% of all malignant canine oral tumors. Tumors in the caudal oral cavity frequently go undetected until they reach considerable size, and definitive surgical treatment typically requires unilateral or bilateral caudal maxillectomy to achieve clean margins.

The complication profile of maxillectomy is well documented. A 2018 study found that 53.4% of dogs undergoing partial maxillectomy experienced substantial intraoperative hemorrhage — with 42.7% of those dogs requiring blood transfusion. Dehiscence occurs in 7 to 33% of cases, with higher rates following caudal maxillectomies. Oronasal fistula, infection, lip trauma, and altered cosmesis round out a complication list that surgeons and owners must weigh carefully.

When maxillectomy is declined or when marginal excision produces a defect that cannot be closed primarily, the options narrow quickly. Mucosal and mucoperiosteal pedicle flaps, axial pattern flaps, free-tissue grafts, and palatal prosthetics have all been described — each with its own technical demands, donor site morbidity, and failure modes. Primary closure in areas of high mechanical stress from mastication and swallowing is often not feasible, and flap dehiscence in this location can have serious functional consequences.

The Case: Why Surgeons Reached for BioSIS

Walker and colleagues at the Atlantic Veterinary College (University of Prince Edward Island) report the case of a 12-year-old castrated male golden retriever referred for evaluation of a palatal mass. CT imaging revealed a 2.7 × 2.0 × 1.5 cm mass extending from the caudal hard palate to the rostral soft palate. Bilateral caudal maxillectomy was recommended for curative-intent resection but declined by the owners due to the risks of hemorrhage, dehiscence, and potential revision surgery.

The owners elected for marginal excision. The mass was removed en bloc, resulting in an approximately 3 cm diameter full-thickness defect at the hard/soft palate junction. Histopathology confirmed a poorly pigmented malignant melanoma with 7 mitotic figures per 10 high-power fields, with tumor infiltrates within 1 mm of the surgical margins.

Primary closure of the defect was not feasible due to tension. A medially positioned palatal flap or split-palatal U-flap were considered but held in reserve as revision options given the owners’ concerns about flap-related complications. The surgical team turned to a xenograft closure.

Technique and Outcomes: What Happened With BioSIS

Four-ply BioSIS was placed over the palatal defect with 3 to 5 mm of overlap at the wound edges and secured using 3-0 polydioxanone sutures in a simple interrupted and mattress pattern. Total surgical time was 67 minutes. The dog recovered uneventfully from anesthesia.

Eight hours post-operatively, the dog was eating hand-fed canned food meatballs. He was discharged 24 hours after surgery.

At two weeks: the defect was healing well, and the BioSIS appeared to be replaced by oral mucosa.

At four weeks: completely healed. No erythema, no discharge, no dehiscence.

At four months: no evidence of tumor recurrence on CT, no regional or distant metastases.

At 22 months: the dog was euthanized for unrelated reasons — persistent lethargy and hyporexia. At the time of euthanasia, no evidence of local tumor recurrence was noted.

No oronasal fistula. No incisional complications. No difficulty eating throughout the follow-up period.

What This Means for Oral Surgery Going Forward

This is the first description of BioSIS use for palatal defect closure in a dog, and the outcome data are clinically compelling. The case demonstrates several specific advantages of the xenograft approach in this anatomic location.

No donor site. Traditional flap techniques require harvesting tissue from within or adjacent to an already compromised surgical field. BioSIS eliminates that requirement entirely. The surgeon works with a single operative site.

Shorter surgical time. The xenograft closure was completed as part of a 67-minute total procedure. Complex flap harvesting and inset would have added substantially to operative time and anesthesia burden in a 12-year-old patient.

Decreased patient morbidity. No donor site means no secondary wound to manage, no second area of potential dehiscence, and no additional tissue trauma in a patient already managing an oral neoplasia diagnosis.

Proven resorption biology. BioSIS does not remain in the body as a permanent foreign material. The extracellular matrix scaffold — collagen, glycosaminoglycans, proteoglycans, growth factors — is gradually replaced by host tissue as fibroblasts infiltrate and lay down organized native collagen. In this case, oral mucosal replacement was visible at two weeks and complete by four weeks. BioSIS completely resorbs, leaving behind only organized, healthy tissue.

Biocompatibility and infection resistance. BioSIS has been reported to be biocompatible and resistant to infection — properties that matter significantly in the oral environment, where bacterial colonization is a constant concern. No infectious complications were reported in this case despite the high-contamination risk of the oral cavity.

The authors note that this technique may be considered following excision of midline palatal neoplasia, and suggest future investigation into congenital palatal defects as another potential application. The precedent in human medicine — Membreno and colleagues described successful BioSIS use for oral defect repair in 11 human patients including tongue, floor of mouth, buccal mucosa, and soft palate — supports the broader applicability of this approach.

For surgeons managing oral neoplasia where primary closure is not possible and flap techniques are declined or carry unacceptable risk for a given patient, BioSIS now has published case evidence as a viable reconstruction option in the veterinary literature.

Learn more about BioSIS ECM and its applications in veterinary surgery at RethinkHealing.com.

Sources

1. Walker MA, Bacon N, Hoddinott KL. Use of porcine small intestinal submucosa for reconstruction of a soft palate defect following marginal resection of a melanoma in a dog. J Small Anim Pract. 2026;67:92–96.
2. Membreno PV, et al. Porcine small intestine graft for reconstruction of oral defects. Laryngoscope Investig Otolaryngol. 2021;6:940–947.
3. MacLellan RH, et al. Intraoperative and postoperative complications of partial maxillectomy for the treatment of oral tumors in dogs. JAVMA. 2018;252:1538–1547.
4. Stoll MR, et al. The use of porcine small intestinal submucosa as a biomaterial for perineal herniorrhaphy in the dog. Veterinary Surgery. 2002;31:379–390.
5. Vanore M, et al. Surgical repair of deep melting ulcers with porcine small intestinal submucosa (SIS) graft in dogs and cats. Vet Ophthalmol. 2007;10:93–99.