Anoplasty for Anal Stenosis

Michael A. Valente

Perioperative Considerations

Anal stenosis is most often the result of iatrogenic injury from an over aggressive hemorrhoidectomy, in which too much anoderm is removed (Fig. 10-1).

FIGURE 10-1 ▪ Severe anal stenosis secondary to hemorrhoidectomy.
Other causes of stenosis may include idiopathic, neoplasm, inflammatory (Crohn), trauma, infectious, or after radiation.
Anoplasty techniques may also be utilized for cases of ectropion, anal ulcer, fissure, fistula-in-ano, and after the excision of premalignant/malignant anal lesions (ie, Paget disease, anal dysplasia/carcinoma).
Other indications include when the anoderm is absent and replaced by scar, most often following excision of anoderm during an operation.
Multiple flap configurations exist, and each type should be used based on the etiology, size/location of the scar, anatomy, and surgeon preference and skill.
Establish the etiology of the stenosis, as this will dictate operative approach.
Suitability/condition of the perianal/gluteal tissues must be assessed.
The presence of Crohn disease, history of radiotherapy, prior attempts at repair, and quality of gluteal skin must also be addressed before repair.
Delineate the location(s) and the extent of the stenosis.
The decision to create a unilateral versus bilateral flap repair is based on the abovementioned information.
Maintain good plastic surgical principles:
- Sharp dissection; little to no cautery
- Broad-based flap with adequate blood supply
- Mobility maximized by releasing the tethering attachments under the donor site rather than aggressive dissection under the flap skin itself
- The principle of anoplasty is to remove the scar, allow the anus to occupy its full length, and then cover the unepithelialized anus with epithelium, in other words, skin.

Operative Preparation

A full cathartic bowel preparation may be given on a case-by-case basis depending on surgeon preference. We prefer a bowel preparation to clear the colon and rectal of stool and to defer stool during early healing.
If not receiving a full bowel preparation, patients will receive two-fleet enemas the morning of the procedure.
Venous thromboembolism prophylaxis is achieved with sequential compression device and subcutaneous anticoagulation agents.
Intravenous antibiotic prophylaxis is given 1 hour prior to incision and includes ceftriaxone 2 g and metronidazole 500 mg.
Foley catheter drainage is recommended for most cases.

Patient Positioning

Patients routinely undergo general endotracheal anesthesia while in the supine position.
Once the airway is secured, the patient is flipped into the prone jackknife position.
A large Kraske roll is utilized by being placed under the iliac crests to properly elevate the buttock and perianal regions.
Exposure to the anus is accomplished by securing the buttocks bilaterally to the operating room table with tape; care is taken to ensure adequate gluteal retraction and exposure, but also that the tape allows for proper access to the soft tissue needed for reconstruction.
The entire perineal and buttock regions are sterilely prepped and widely draped.

Approach and Equipment

Needle-tip Bovie electrocautery pen
Indelible marking pen
3-0 absorbable suture (Vicryl or polydioxanone)
Local anesthetic (lidocaine without epinephrine)
Kraske roll
3 in adhesive tape
Lighted Hill-Ferguson anoscopes
Betadine prep for anal mucosa; alcohol-based prep for gluteal skin

Techniques for Anal Stenosis

Various types of anoplasty exist, including the house, diamond, U, or V-Y. These are the most commonly performed anoplasty techniques for anal stenosis. The technique of S-plasty is usually reserved for the most severe strictures with extensive loss of anoderm.
For scarring that is >50% circumference, bilateral flaps may be needed. In general, performing one side is acceptable initially, followed by the contralateral side only if needed.
The goal of making a flap is to provide viable tissue to fill the defect that is created by stricture excision and also allows for prevention of recurrent cicatrix and contracture.

FLAP PREPARATION AND SCAR RELEASE

The flap lines are drawn with indelible marking pen (Fig. 10-2).

FIGURE 10-2 ▪ House flap.
A longitudinal incision is made proximal to the dentate line with a scalpel to the perianal skin for the length of the stenosis. In cases where a house flap is being utilized for a sizeable stenosis (dentate line to perianal skin), a radial incision is also created inside the anal canal and on the anoderm where the scar ends, in conjunction with the longitudinal incision to completely release the large cicatrix (Fig. 10-3).

FIGURE 10-3 ▪ Indelible ink to mark out a diamond flap.
This cicatrix must be excised/removed, and the underlying anal sphincter muscles must be preserved. The length of this initial incision will roughly correspond to the length of the flap (Fig. 10-4).