Complex Anorectal Fistulas
Vladimir Bolshinsky
Stefan D. Holubar
Perioperative Considerations
Fistulas are characterized based on their relationship with the anal sphincter: intersphincteric, transsphincteric, suprasphincteric, and extrasphincteric (Fig. 12-1).
FIGURE 12-1 ▪ Anorectal fistula types: (A) intersphincteric (type I); (B) transsphincteric (type II); (C) suprasphincteric (type III); and (D) extrasphincteric (type IV). (Reprinted with permission, Cleveland Clinic Center for Medical Art & Photography © 2019. All Rights Reserved.)
Determining the anatomy of each unique fistula is critical to maximizing healing and minimizing problems with continence. This may involve:
Examination under anesthesia
Magnetic resonance imaging
Ultrasound
A general “rule of thumb” dictates that it is typically safe to divide <one-third the length of the sphincter. Despite this, decreased continence may occur even when division of the sphincter met this condition, and patients should be counseled accordingly.
Care must be taken for those with prior anorectal surgery, Crohn disease, baseline decreased continence, anterior fistula in women, and other conditions where division of the sphincter may lead to further deterioration in continence.
Patients should be aware that multiple operations may be required to ultimately allow fistulae to heal.
Asymptomatic fistula may be surveilled without any operative intervention.
Sterile Instruments/Equipment
Equipment used for anorectal cases are as follows:
Anal retractors, fiberoptic lighted: small, medium, and large
Hill-Ferguson retractors (Fig. 12-2): often used for perianal cases placed in lithotomy position (Fig. 12-3)
Fansler retractors (Fig. 12-4): small, used selectively for perianal cases such as those placed in prone (ie, Kraske) position (Fig. 12-5A and B) or those with large redundant mucosa
Pratt bivalve anal retractor (Fig. 12-6)
Right-angle retractors
FIGURE 12-2 ▪ Hill-Ferguson lighted anoscopes of various sizes.
FIGURE 12-3 ▪ Lithotomy position.
FIGURE 12-4 ▪ Fansler lighted anoscope.
FIGURE 12-5 ▪ A. Operating room table setup with padding for the patient in prone (ie, Kraske) position. B. Kraske position on the operating room table.
FIGURE 12-6 ▪ Pratt bivalve anoscope.
Set of Lockhart-Mummery fistula probes (Fig. 12-7)
Set of curettes (Fig. 12-8)
00-silk ties
FIGURE 12-7 ▪ Set of Lockhart-Mummery fistula probes.
FIGURE 12-8 ▪ Set of curettes to debride the tract.
Silicon, radio-opaque yellow (mini) vessel loop, 1.3 mm wide and 0.9 mm thick, or a blue (maxi) vessel loop, 2.5 mm wide, 1 mm thick (Fig. 12-9)
Monopolar electrocautery
We routinely use 40 cut/60 coagulation settings, pure or blend
A needle tip may be used for endorectal advancement flap (ERAF)
Pezzer (mushroom) drains, size ranging from 10 to 32Fr (Fig. 12-10)
¼ and ½ in Penrose drains
Hydrogen peroxide diluted 50-50 with sterile normal saline, placed in a 10-mL syringe with a 14-gauge angiocatheter or a blunt-tip needle
 FIGURE 12-9 ▪ Silicon vessel loop for draining seton. |
 FIGURE 12-10 ▪ Pezzer (ie, mushroom) drains, size ranging from 10 to 32Fr. |
Positioning
Positioning of the patient is dependent on the site of the internal opening, with prone jackknife being optimal for anterior internal opening and lithotomy for fistulas with a posterior internal opening.
In lithotomy (Fig. 12-2):
Emphasis on ergonomics cannot be understated. The edge of the operating table may need to be moved in the caudal direction, to ensure that the chair and feet of the operating surgeon are not restricted by the base of the operating table. In addition, the patient’s buttocks overhanging the edge of the operating table.
In prone jackknife:
We place two shoulder rolls under the chest (taking special care to protect the breasts) and a foam pillow (Kraske roll) under the pelvis (taking special care to protect the genitals from pressure injury) (Fig. 12-4A).
We typically secure the patient with a belt to prevent inadvertent rolling (Fig. 12-4bB).
We use tape to laterally retract the buttocks, with or without benzoin.
Excessive tape traction will result in iatrogenic tearing (fissuring) of the anoderm—avoid.
Setons
Draining setons are used as a bridge to definitive repair (commonly performed 6 weeks after insertion), or as semi-permanent drainage for refractory fistulas or where definitive repair is contraindicated (eg, severe perianal Crohn disease).
If the seton breaks and falls out, and the track is completely epithelialized, it may not need to be replaced. However, the patient should be informed of the risk of abscess and recurrent symptomatic fistula, heralded by a change in symptoms such as pain or increased drainage, respectively.
Cutting setons may be used as a “slow fistulotomy” in selected cases. This is rarely indicated.
Technique
Draining Seton
A standard perianal block is performed (Fig. 12-11) by identification of the pudendal nerve as it traverses by the ischial tuberosity. Additional perianal anesthetic may be placed around the sphincter complex itself.
FIGURE 12-11 ▪ Perianal block using local anesthesia.
Having identified the track using the Lockhart-Mummery fistula probes, we secure a 00-silk tightly onto the probe and then sequentially exchange this for an 00-silk tie and a yellow vessel loop (Fig. 12-12).
The yellow vessel loop is the smallest size to ensure adequate drainage and is well tolerated by the patients.
FIGURE 12-12 ▪ Draining seton in place using a silastic vessel loop.
Place a hemostat on each end of the vessel loops for traction.
We overlap the two ends of the seton and assess tension.Related posts:
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