Review Article
Surgical Management of Deep Postanal Abscess and Horseshoe Fistula of Cryptoglandular Origin – A Review
Nsikak J Umoh*
Department of Colon and Rectal Surgery, Woodlands Colon and Rectal Associates PLLC, USA
*Corresponding author: Nsikak J Umoh, Department of Colon and Rectal Surgery, The Woodlands Colon and Rectal Associates PLLC, 201 Kingwood Medical Drive, Suite A450, Kingwood TX 77339, USA
Published: 18 Jul, 2017
Cite this article as: Umoh NJ. Surgical Management of
Deep Postanal Abscess and Horseshoe
Fistula of Cryptoglandular Origin – A
Review. Clin Surg. 2017; 2: 1570.
Abstract
Deep post anal space abscesses and horse shoe fistulae have represented a challenging problem to both patient and surgeon over the years. That concern remains true to this day. The potential morbidity of post- operative fecal incontinence and recurrent disease plague the decision making for today’s surgeon as he/she considers several management options. Over time, newer sphincter sparing surgical techniques have been advocated for the management of this problem. This article reviews the current available literature on the surgical management of this ailment specifically highlighting technique, potential complications and disease recurrence.
Introduction
Anorectal abscesses are one of the commonest anorectal problems encountered by surgeons
[1]. They are usually cryptoglandular in origin and are associated with an anal fistula about 30%
– 70% of the time [2-4]. When the incriminating gland originates from the posterior midline and
traverses the conjoint longitudinal muscle into the deep postanal space, a deep postanal abscess
results. Further extension of this infective process into the unilateral or bilateral ischiorectal fossa
leads to a horseshoe abscess [5]. This type of abscess accounts for about 15% – 20% of anorectal
abscesses and its management remains challenging to surgeons to this very day [6].
Anatomically, the deep postanal space (DPAS) is bounded anteriorly by the posterior aspect of
the deep external sphincter, superiorly by the levator any which inserts into the fourth sacral and
first coccygeal bodies by way of the anococcygeal raphe, and, inferiorly by the superficial external
sphincter as it inserts into the tip of the coccyx via the anococcygeal ligament [7]. This space is in
continuity with both ischiorectal fossae. For this reason, lateral spread of the suppurative process
goes to the ischiorectal fossae resulting in the horseshoe abscess. If untreated, further spread to the
lower abdominal wall, scrotum, and perineum can result. Chronic draining sites on the buttocks
(horseshoe fistulae) can also result.
DPAS abscesses almost invariably are associated with a posterior midline fistula in ano. While
it is common consensus in the surgical community that drainage of the abscess cavity is essential,
what to do with the associated fistula remains a dilemma. Simple incision and drainage of the
DPAS abscess without addressing the fistula has been associated with an exceptionally high rate
of recurrent DPAS abscesses [8]. It is thus paramount that the surgeon attempts to identify and
manage the associated fistula. A major concern for surgeons is the possibility of post-procedure fecal
incontinence given the amount of anal sphincter muscle involved by this transphincteric fistula.
Also, given the complexity involved in treating this condition, many patients require multiple
operations. This article reviews the current surgical management options for deep postanal abscess
and horseshoe fistula with particular attention to surgical technique, potential complications and
recurrence.
Methods
A thorough search for articles was performed using MEDLINE, PubMed and Cochrane Database of Systemic Reviews. Only articles written in English were considered. Keywords used in the search included horseshoe abscess, horseshoe fistula, and deep post anal abscess. In addition, searches of the embedded references in the articles were also conducted.
Surgical Management Modalities
Incision and drainage with primary fistulotomy
The initial approach to treatment of DPAS abscesses with horseshoe fistula required complete unroofing of the fistula tracts. This involved severance of the superficial
external sphincter so the lower anal canal could shift anteriorly
allowing the severed ends of the subcutaneous and deep external
sphincters to separate more for adequate drainage. This technique
was shown to be associated with very high rates of impaired fecal
continence [9]. Subsequently, Hanley described a more conservative
surgical technique at that time that included a primary fistulotomy
while requiring separation of the superficial external sphincter
muscle fibers as opposed to severance of this structure. In Hanley’s
technique, the internal opening of the fistula in the posterior midline
is first identified. It is then probed to gain access to the deep postanal
space. A fistulotomy is performed from the internal opening towards
the coccyx severing the distal portion of the internal sphincter, the
subcutaneous portion of the external sphincter, and a portion of the
deep external sphincter. It is completed by separating the involved
portion of the superficial external sphincter along its muscle fibers.
The DPAS is then adequately drained and curetted. If a horseshoe
abscess or fistula is present, counter incisions are made over it on the
respective ischiorectal fossa for adequate drainage. This resulted in
minimal to no anterior displacement of the anal canal and following
healing, there was minimal anatomic defect. Importantly, despite the
amount of muscle involved in the fistulomy, no significant reports of
long term incontinence were observed. Hanley et al. reviewed data on
41 patients (10 acute, 31 chronic) with horseshoe abscesses or fistula
over a 10 year period. The authors report that all patients were healed
between 5 to 12 weeks and there were no problems with incontinence
[10]. In another retrospective study, Hamilton reviewed data over a
5 year period involving 65 patients with horseshoe fistulae. Out of 57
patients who eventually followed up, there were 4 (7%) recurrences.
No reports of incontinence were noted. Held reviewed their data on
69 patients over a period of 10 years. Multiple modalities were used
to treat patients over this time. These included “incision and drainage
alone”, “incision, drainage and primary fistulotomy”, “incision,
drainage, primary fistulotomy and counter drainage” and “incision,
drainage and insertion of seton”. Incision and drainage alone was
performed only in patients in whom the offending crypt (internal
opening) could not be identified. Among these patients, there was
60% recurrence. Those patients, who had the abscess confined to the
DPAS and an identified internal opening, underwent incision and
drainage with primary fistulotomy. They were found to have an 8%
recurrence rate. For the patients who had a horseshoe component
in addition to the DPAS abscess, they underwent counter-drainage
of the affected ischiorectal abscess(s) in addition to the primary
fistulotomy. This group of patients had a 28% recurrence rate. The
authors attributed this to the possibility of premature closure of the
posterior midline fistulotomy wound and suggested that prolonged
drainage of this wound would lead to a reduction in the incidence
of recurrence. More recently, Inceoglu and Gencosmanoglu [11]
retrospectively reviewed data on 25 patients who underwent incision
and drainage with primary fistulotomy for DPAS abscess. In their
study, patients who had an associated horseshoe fistula had complete
fistulotomy of all the fistula arms. They report no recurrences and no
issues with fecal incontinence after a median follow up of 35 months.
Incision and drainage with seton fistulotomy
This is a modification of Hanley’s technique but in this case,
the fistulotomy is via a cutting Seton. Here, access is also gained to
the DPAS by probing through the internal opening. The superficial
external sphincter is separated along its fibers over the DPAS and a
draining Seton placed to communicate with the internal opening in
the posterior midline. Counter-incisions are made on the ischiorectal
fossa for horseshoe abscesses. The skin and in the midline is cut to
allow for subsequent tightening of the Seton on an outpatient basis
to complete the fistulotomy. The presence of the Seton converts the
acute abscess to a chronic draining fistula thus allowing for adequate
drainage of the DPAS. Subsequently, the cutting Seton fistulotomy
takes care of the fistula [12]. In the study by Held, 7 patients underwent
this procedure. The authors found no recurrences and no issues with
fecal incontinence in these patients.
Ustynoski et al. [13] reviewed their data on 11 patients with
horseshoe abscess fistulae. Seven of these patients had posterior
horseshoe fistulae and four had anterior horseshoe fistulae. All
patients were treated with incision, drainage and Seton fistulotomy.
The total healing time per patient was about 21 weeks. Two patients
(18.1%) had a recurrence – both of which had DPAS abscesses. No
information on fecal incontinence was reported in that study [13].
Pezim [14] reviewed data of 24 patients who had Seton fistulotomy
for horseshoe fistula. The author reported that 21% of patients
required re-operations and 96% of patients were eventually healed.
By the end of follow up, only 64% said they had normal continence.
Multiple other studies have consistently shown that fecal continence
is preserved with this procedure with fairly acceptable recurrence
rates [15-17].
Sphincter Sparing Approaches
Intersphincteric approach
This sphincter sparing approach was first described by Tan et al.
[18]. It is based on the concept of the Ligation of Intersphincteric
Fistula Tract (LIFT) procedure described by Rojanasakul [19].
It involves gaining access to the deep post anal space via the
intershincteric space and posteriorly over the external sphincter. The
deep post anal space is drained and curetted, the internal opening of
the fistula on the surface of the internal sphincter is closed, a suction
drain is left in the DPA space and the intersphincteric space is then
re-apposed. The authors found that for patients who primarily had
this as a single stage procedure, there was 91.7% success. However,
those patients who had a prior drainage prior to this approach had an
80% failure rate. This was attributed to the difficulty with dissection
in the intersphincteric space and identifying the intersphincteric
portion of the fistula tract following prior drainage and subsequent
fibrosis. Recurrences were successfully managed with repeat
drainage, placement of draining Setons and a subsequent endoanal
advancement flap procedure. The authors do not present any data on
incontinence rates in their study.
Advancement Flaps and Direct Closure
The use of advancement flaps usually involves a two stage procedure. The first stage entails adequate drainage of the DPAS with Seton placement and the second stage is the flap procedure to close the fistula. This method has been used to successfully manage recurrent abscesses following the intersphincteric approach. However, its success depends largely on the adequacy of the drainage of the DPAS. Koehler et al. [20] used 4 different approaches to close the internal fistula opening in patients with horseshoe fistulas. Three of these were advancement flaps - mucosa-submucosa flap (MSAF), rectal wall advancement flap (RWAF), anocutaneous advancement flap (ACAF). The last approach was direct closure of the internal opening. The flaps were constructed about 2 to 3 months following abscess drainage and Seton placement in patients who presented with abscesses. Recurrence rates were 25% for MSAF, 35% for RWAF and 25% for ACAF. This was comparable to results historically seen in patients undergoing primary fistulotomy. The authors report a decline in continence levels in about 32% of patients. The authors therefore concluded that this approach is reasonable. In select patients, direct closure of the fistulous tract has been found to be a viable option. These are patients with a very elastic anal canal. Koehler et al. [20] reported results in 11 patients who underwent direct closure of the internal fistula opening following adequate abscess drainage and Seton placement. A closure of both the muscular defect and the overlying mucosa was performed. They note excellent results with this approach. All patients were healed with 0% recurrence.
Conclusion
In current surgical practice, the management of horseshoe abscess/fistulae and DPAS abscesses remain a challenge. As newer sphincter sparing surgical management modalities are added to the armamentarium of the colorectal surgeon, it is anticipated that there will be declining concerns for post-operative fecal incontinence. Recurrent disease will continue to remain a challenge and will be the benchmark for determining successful treatment. Finally, irrespective of the surgical technique used, the key to successful management of this complex problem remains the same - ensuring complete and adequate drainage of the DPAS.
References
- Steele SR, Kumar R, Feingold DL, Rafferty JL, Buie WD; Standards Practice Task Force of the American Society of Colon and Rectal Surgeons. Practice parameters for the management of perianal abscess and fistula-in-ano. Dis Colon Rectum. 2011;54(12):1465-74.
- Vogel JD, Johnson EK, Morris AM, Paquette IM, Saclarides TJ, Feingold DL, et al. Clinical Practice Guideline for the Management of Anorectal Abscess, Fistula-in-Ano, and Rectovaginal Fistula. Dis Colon Rectum. 2016;59(12):1117-33.
- Hamalainen KP, Sainio AP. Incidence of fistulas after drainage of acute anorectal abscesses. Dis Colon Rectum. 1998;41(11):1357-61; discussion 1361-2.
- PARKS AG. Pathogenesis and treatment of fistuila-in-ano. Br Med J. 1961;1(5224):463-9.
- Hanley PH. Conservative surgical correction of horseshoe abscess and fistula. Dis Colon Rectum. 1965;8(5):364-8.
- Hamilton CH. Anorectal problems: the deep postanal space--surgical significance in horseshoe fistula and abscess. Dis Colon Rectum. 1975;18(8):642-5.
- Netter FH. Pelvis and Perineum. Atlas of Human Anatomy. 4th ed. Philadelphia, Pennsylvania: Saunders Elsevier. 2006; 396.
- Held D, Khubchandani I, Sheets J, Stasik J, Rosen L, Riether R. Management of anorectal horseshoe abscess and fistula. Dis Colon Rectum. 1986;29(12):793-7.
- Bennett RC. A review of the results of orthodox treatment for anal fistulae. Proc R Soc Med. 1962;55:756-7.
- Hanley PH, Ray JE, Pennington EE, Grablowsky OM. Fistula-in-ano: a ten-year follow-up study of horseshoe-abscess fistula-in-ano. Dis Colon Rectum. 1976;19(6):507-15.
- Inceoglu R, Gencosmanoglu R. Fistulotomy and drainage of deep postanal space abscess in the treatment of posterior horseshoe fistula. BMC Surg. 2003;3:10.
- Hanley PH. Reflections on anorectal abscess fistula: 1984. Dis Colon Rectum. 1985;28(7):528-33.
- Ustynoski K, Rosen L, Stasik J, Riether R, Sheets J, Khubchandani IT. Horseshoe abscess fistula. Seton treatment. Dis Colon Rectum. 1990;33(7):602-5.
- Pezim ME. Successful treatment of horseshoe fistula requires deroofing of deep postanal space. Am J Surg. 1994;167(5):513-5.
- Leventoglu S, Ege B, Mentes BB, Yorubulut M, Soydan S, Aytac B. Treatment for horseshoe fistula with the modified Hanley procedure using a hybrid seton: results of 21 cases. Tech Coloproctol. 2013;17(4):411-7.
- Browder LK, Sweet S, Kaiser AM. Modified Hanley procedure for management of complex horseshoe fistulae. Tech Coloproctol. 2009;13(4):301-6.
- Noori IF. Management of complex posterior horseshoe anal fistula by a modified Hanley procedure: clinical experience and review of 28 patients. Basrah Journal of Surgery. 2014:54-61.
- Tan KK, Koh DC, Tsang CB. Managing Deep Postanal Space Sepsis via an Intersphincteric Approach: Our Early Experience. Ann Coloproctol. 2013;29(2):55-9.
- Rojanasakul A. LIFT procedure: a simplified technique for fistula-in-ano. Tech Coloproctol. 2009;13(3):237-40.
- Koehler A, Risse-Schaaf A, Athanasiadis S. Treatment for horseshoe fistulas-in-ano with primary closure of the internal fistula opening: a clinical and manometric study. Dis Colon Rectum. 2004;47(11):1874-82.