Sufficient patient population achieved; decision not due to product complaints.

Primary outcome variable is healing at the final follow up visit.

The primary purpose of this prospective, multicenter, observational, single arm study is to further substantiate efficacy of the GORE® BIO-A® Fistula Plug when used as a soft tissue reinforcement of anal fistula repair and healing.

Inclusion Criteria:

• Transsphincteric fistula consisting of 1 tract(defined as a fistula which would not be amenable to fistulotomy); determined during operative procedure
• Likely cryptoglandular origin
• Must be at least 18 years of age
• Patients informed about the study, and will have read, understood and signed the patient informed consent and authorization to use PHI data, as applicable
• Patients willing and able to submit to postoperative follow-up evaluations

Exclusion Criteria:

• Crohn's Disease
• Evidence of on-going local infection
• History of more than 2 prior definitive repair attempts; repair attempt is defined as any of the following: advancement flap, cutting seton, fistulotomy, fistulectomy, fibrin glue, anal fistula plug, LIFT
• Superficial fistulas without any muscle involvement
• Fistulae of traumatic origin, including obstetric
• Intersphincteric fistulas that would be candidate for fistulotomy
• Horseshoe or multi-tract fistulas
• Ano-vaginal or recto-vaginal fistulas
• Anastomotic fistulas (ileo-anal, colo-anal)
• A wound-healing or autoimmune disorder (including insulin-dependent diabetics)
• Subjects who are immunocompromised such as, with HIV, or currently receiving chemo or radiation therapy
• Subjects who are immunosuppressed, e.g. transplant patients, patients taking steroids, TNF agents, methotrexate
• History of prior or current pelvic radiation
• Difficulty comprehending or complying with the study (in surgeon's opinion)

All patients presenting with anal fistulae that meet inclusion and exclusion criteria.