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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1056_Библиотеки_им_академика_М_И_Перельмана.pdf
Fistulectomy
18
Maher A. Abbas
Contents
1 Introduction . ............... .................................................................. 284
2 Preoperative Evaluation ... . . . ...... . . . . ...... . . . . ...... . . . . ...... . . . . .... . . . . . ...... . . . . .... 286
2.1 Patient Selection ....................................................................... 286
2.2 Imaging . ............................................................................ ... 286
2.3 Physiologic Testing . ................................................................... 289
2.4 Endoscopic Examination .............................................................. 290
3 Technique ................................ .................................................... 292
3.1 Patient Preparation ... . . . . ....... . . . . ....... . . . . . ...... . . . . . ...... . . . . . ....... . . . . ..... 292
3.2 Patient Positioning .................................................................... 294
4 Postoperative Care ........................................................................... 297
5 Results .............................. ....................................................... .. 298
5.1 Fistulectomy ............... .................................................... ........ 300
6 Fistulectomy with Sphincter Reconstruction ............................................... 303
7 Conclusions .................................................................................. 305
References ............................ ............................................... ............ 306
Abstract
Anal fistula is one of the most common proctologic disorders treated by surgeons.
The goal of surgical intervention in the management of this disease is to control
and eradicate the sepsis, minimize the risks of the procedure, maintain continence, and prevent recurrence. Numerous operations are currently available to
treat anal fistula. They are generally classified into two types: sphincter preser ving and nonsphincter preserving. Anal fistulectomy is one of the oldest and most
established operations for anal fistula. The operation entails the surgical excision
of the fistulous tract with eradication of the sepsis. Excision of the tract can be
achieved by a coring-out technique or alternatively by division of the tissue
caudal to the fistula with excision of the epithelialized fistulous tract.
Fistulectomy yields a high healing rate. The technical conduct of this operation
M. A. Abbas (*)
King’s College Hospital London, Dubai, UAE
© Springer Nature Switzerland AG 2022
C. Ratto et al. (eds.), Anal Fistula and Abscess, Coloproctology,
https://doi.org/10.1007/978-3-030-76670-2_20
283
284 M. A. Abbas
is of paramount importance in order to minimize sphincter muscle loss. Due to the
potential impact of fistulectomy on sphincter function, patient selection is key to
minimize risks of incontinence as this technique is not suitable for a subset of
patients such as those with high complex fistula with prior sphincter dividing
procedures, a weak functional status of the anal sphincter due to previous
traumatic childbirth, or neurologic disorders. The addition of sphincter reconstruction in some patients undergoing fistulectomy can potentially improve functional outcome.
Keywords
Anal fistula · Fistulectomy · Fistula removal · Incontinence · Recurrence
sphincter repair
1 Introduction
While most proctologic disorders are benign in nature and are rarely life threatening,
they represent significant nuisance to the patient and negatively impact quality of life
and daily living. Anal fistula is one of the most common proctologic conditions
treated by surgeons. The majority of anal fistulas are cryptoglandular in nature with a
smaller subset caused by Crohn’s disease, atypical infections, radiation, and/or
trauma. The initial presentation of anal fistula varies from an acute abscess to a
spontaneously draining fistula. Approximately 2/3 of all patients who present with
an acute perirectal abscess will develop chronic fistula (Hamadani et al. 2009). The
mechanism of chroni c fistula formation remains unclear although recently an inflammatory process has been postulated based on immunopathological characterization
of cryptoglandular fistulas (Ratto et al. 2016). The goal of surgical intervention in the
management of this disease is to control and eradicate the sepsis, minimize the risks
of the procedure, prevent recurrence, and maintain continence. Outcome of surgical
intervention is determined by the fistula classification and choice of operative
intervention (Abbas et al. 2011). The deeper and more complex the fistula, the
lower the success rate of the intervention and the higher the rate of complications
and potential deterioration in continence function.
Since ancient times, the surgical treatment of anal fistulas has gradually evolved
over many centuries (Ortega et al. 2017). The last century, especially the latter part of
it, has seen the introduction of numerous new operations aimed at minimizing the
amount of trauma to the anal sphincter complex. This group of procedures, classified
as sphincter preserving interventions, is in contrast to the nonsphincter preserving
operations which are very effective at eradication of the anal sepsis but associated
with some morbidity and risks for continence disturbance. It is important to note that
in general, the overall interest in sphincter preserving operations is not to increase the
success rate of nonsphincter preser ving operations, but rather to decrease the risks of
18 Fistulectomy 285
postoperative incontinence and to enhance the recovery of the patient. Sphincter
preserving operations usually entail obliteration of the tract by closure of the internal
opening (endorectal advancement flap or dermal flap), division of the fistula in the
intersphincteric plane (LIFT and BioLIFT procedures), filling of the tract (anal
fistula plug, injectable glue), or scarring and fibrosing the tract (video-assisted anal
fistula treatment procedure (VAAFT), or laser procedures such as FiLac™)(Abbas
and Sherman 2017; Soltani and Kaiser 2010; Abbas et al. 2008;Nelsonetal.2000;
Rojanasakul 2009; Ellis 2010; Loungnarath et al. 2004; Schwandner et al. 2009;
Lawes et al. 2008; Meinero and Mori 2011;Elfekietal.2020; Wilhelm et al. 2017).
Variations of such procedures have been described as a single operation (different
types of plugs or injectables, or different laser probes) or in combination with other
procedures (VAAFT with the addition of endorectal advancement flap). With the
exception of the endorectal advancement flap, which can yield high success rate in
expert hands, some of these sphincter preserving operations have been associated
with low success rate after initial pro mising reports (injectables and anal fistula
plug) (Loungnarath et al. 2004; Lawes et al. 2008). The LIFT procedure was
initially associated with high success rate but subsequent series have reported
modest results (Bleier et al. 2010). The role of scarring procedures such as
VAAFT and laser interventions is currently evolving with most of the available
scientific data originating from a few centers around the world. In my personal
opinion, the verdict on the long-term effect of such procedures is still out. More
data from various centers is needed to determine the long-term outcome of these
techniques, especially since some series report their results with the addition of an
endorectal advancement which can yield the same if not higher success rate as a
stand-alone technique.
With the above in mind, it is important to note that operations which can impact
the sphincter muscle such as anal fistulotomy or fistulectomy are associated with
the highest success rate of any treatment for anal fistula with the least incidence of
failure or recurrence (Hall et al. 2014; Abbass and Abbas 2014). Both techniques
remain the most commonly performed anal fistula operations globally (Ratto et al.
2019). Fistulectomy is one of the oldest and most established operations for anal
fistula. The operation entails the surgical excision of the fistulous tract with
eradication of the sepsis. The excision of the fistulous tract can be achieved via
two different techniques: one that entails coring out the fistulous tract and the other
which requires division of the tissue caudal to the fistula with excision of the
epithelialized fistuloustract.Thisoperationisassociatedwithahighhealingrate.
The technical conduct of this operation is of paramount importance in order to
minimize sphincter muscle loss. Due to the potential sphincter altering nature of
this procedure, patient selection is key to minimize the risks of incontinence as t his
technique is not suitable for all patients. In this chapter, I would like to discuss the
various aspects of this operation from patient selection and evaluation to preoperative preparation, from the technical steps in the operating to postoperative care,
and outcome results.
286 M. A. Abbas
2 Preoperative Evaluation
2.1 Patient Selection
The ideal patients for anal fistulectomy are those with low trans-sphincteric fistula
and those without prior anal surgery or trauma with significant loss of sphincter
muscle (such as those with prior fistulotomy, sphincterotomy, previous rectal resection for malignant or benign disease, or females with a history of traumatic obstetrical injuries like Grade 3 or 4 perineal tear, full thickness anterior midline
episiotomy, traumatic forceps, or vacuum suction delivery). For patients with low
risk for incontinence, a general rule is that division of up to 1/3 of the sphincter
muscle can be carried out safely, especially for posterior-based fistula in males. In
order to mitigate the potential risk of incontinence, anal sphincter reconstruction can
be undertaken in patients undergoing the dividing type of fistulectomy. Patient
selection is key to avoid a poor functional outcome. It is based on an accurate
assessment of the prior surgical and medical history, a survey of the patient’s
continence level through a standard survey like the Cleveland Clinic Florida Fecal
incontinence score (Jorge and Wexner 1993), and a careful evaluation of the patient’s
bowel habits through a bowel function questionnaire like the Bristol stool chart
(Lewis and Heaton 1997). Adjunct to this evaluation include the physical examination, physiologic pelvic floor testing, and/or imaging in select patients. The physical
examination includes a sensory assessment to ensure the patient has intact sensation
to dull and sharp touch in the perianal and perineal areas, an external visual
inspection of the anus and the perineum for any obvious gross defect in the lower
aspect of the sphincter, and a careful assessment of the sphincter tone at rest and with
active squeezing.
Contraindications to fistulectomy include multiple prior anal operations with
significant muscle loss, baseline continence disturbance, poor bowel function with
frequent or diarrheal stools, anterior fistula in females with significant prior
traumatic obstetrical history such as tears or stretch injuries with forceps or
vacuum delivery, rectovaginal fistula, prior radiotherapy for gynecologic, urologic,
or anorectal malignancy, and active inflammatory bowel disease especially patients
with Crohn’s disease.
2.2 Imaging
The use of preoperative imaging for anal fistula ha s not been universally standardized with significant variation in clinical practice patterns based on geographical
locations and academic training backgrounds (Ratto et al. 2019). While some
surgeons advocate obtaining radiologic studies for all patients with anal fistula, my
personal approach is one of selective imaging. Uncomplicated low-lying fistula that
are clearly delineated by the bedside examination do not require imaging. Such
18 Fistulectomy 287
Fig. 1 Intersphincteric fistula
with good demonstration of
the internal opening by the
probe
fistulas include subcutaneous, intersphincteric, or low trans-sphincteric fistula with a
direct radial tract demonstrated by a probe insertion from the external to the internal
opening. Such examination can be performed in the clinic when tolerated by the
patient and the findings confirmed in the operating room under anesthesia (Fig. 1).
An example of simple low-lying fistula is a straight tract that is readily palpable
under the skin upon insertion of the probe. With these physical findings, the amount
of tissue involved often consists of subcutaneous tissue, distal fibers of the internal
sphincter muscle, and a portion of the subcutaneous external sphincter muscle. In
some cases, subcutaneous skin and fat along with internal sphincter muscle are
caudal to the fistula without involvement of the external sphincter muscle.
In my practice, I consider imaging for patients with persistent or recurrent fistula
after prior surgical interventions, those with long tracts with a lateral external
opening on the buttocks or perineal skin opening (Fig. 2), those with multiple
external openings (Fig. 3), patients with high tracts on physical examination especially those with palpable induration of the supral evator area or high internal
opening above the dentate line, females with prior obstetrical trauma, patients with
baseline continence issues, and patients with inflammatory bowel disease.
Several imaging modalities have been studied in the past including
fluoroscopy-based fistulography, computed tomography (CT), endoanal ultrasound,
and magnetic resonance imaging (MRI). While a fluoroscopic-guided fistulogram
288 M. A. Abbas
Fig. 2 Long fistula tract with
external opening in the
anterior perineum in the
posterior aspect of the scrotum
(arrow)
was commonly performed in the past, it is of limited value currently as it provides
little information about the depth of the fistula or anal sphin cter involvement. CT
scan can be useful in some patients with acute perianal abscess, especially in those
with persistent or recurr ent abscess after incision and drainage and those with
suspected internal abscess or horseshoe abscess (Fig. 4). However, CT scan is less
helpful in delineating the anatomy of the fistula in comparison to endoanal ultrasound or MRI. Three-dimensional (3D) ultrasound is very useful in delineating the
fistula anatomy, in revealing any associated abscess cavity, and in demonstrating any
sphincter abnormality if present (Murad-Regadas et al. 2010; Garcés-Albir et al.
2016). Hydrogen peroxide injection through the external opening can further
enhance the sensitivity of 3D ultrasound (Fig. 5). In addition to its clinical value,
the advantages to 3D ultrasound are that it can be performed and interpreted in the
clinic by the treating surgeon as part of the initial evaluation with minimal
discomfort or risk to the patient. The study is inexpensive in most settings and
can be repeated as needed. The main challenge of 3D ultrasound is that it is not
readily available in most institutions due to the significant financial investment in
the equipment. I n the last decade, MRI of the pelvis has gained significant
momentum in the evaluation of anal fistula and it has become the preferred
imaging modality in managing anal fistula. The advantages of MRI include a
global assessment of the pelvis and high definition demonstration of the fistula
tract and any associated abnormalities of the sphincter muscle (Fig. 6). The
18 Fistulectomy 289
Fig. 3 Multiple external skin
openings in a patient with
horseshoe fistula
disadvantages of MRI are the higher cost of the study and the lack of radiologic
expertise in some centers for accurate reporting and depiction of the findings in
relationship to the anorectal anatomy.
2.3 Physiologic Testing
While not a mandatory part of anal fistula management, pelvic floor physiologic
testing can be a helpful adjunct in the evaluation of some patients who are perceived
at increased risks for incontinence. Anorectal manometry with rectal compliance
testing (Fig. 7) and pudendal nerve studies (Fig. 8) are readily available testing
modalities in most specialized coloproctology units. The selective use of pelvic floor
testing can guide the surgeon in the choice of the most appropriate operation for the
patient and the studies are useful in counseling the patient about treatment options.
They can be obtained preoperatively an d repeated postoperatively if needed. Preparation for these procedures requires one or two rectal enemas to clean the rectum.
The studies are performed in the office with an awake patient. Important parameters
to evaluate are the patient’s resting and squeeze pressures, rectal compliance (first
sensation, urge pressure, and maximum pressure tolerated), and pudendal nerve
terminal motor latency (PNTML) testing. Under most circumstances, a weak resting
290 M. A. Abbas
Fig. 4 CT scan demonstrates a horseshoe fistula with abscess
or squeeze pressure, poor rectal compliance, and pudendal neuropathy are contraindications to fistulectomy due to the increased risk of incontinence.
2.4 Endoscopic Examination
Endoscopic exami nation of the large bowel is undertaken in some patien ts with anal
fistula. A careful history is taken from the patients to assess for the presence of any
gastrointestinal symptoms such as pain from oral ulcerations, abdominal pain,
cramping, bloating and distention, diarrhea, and blood in the stool. Stool tests are
often obtained and checked for calprotectin level and the presence of occult blood.
Indications for endoscopic evaluation are broadly divided into screening, surveillance, and diagnostic indications. Patients over the age of 45 years, those with a
personal history of colorectal neoplasm (polyps and tumors), those with significant
family history of colorectal malignancy, and those with an established history of
inflammatory bowel disease should be considered for screening or surveillance
colonoscopy as deemed necessary based on the patient’s history. Patients who
present with anal fistula and other symptoms potentially attributed to colorectal
disease such as rectal bleeding, diarrhea, severe constipation, abdominal pain, and
distention benefit from a diagnostic colonoscopy to further assess the symptoms.
18 Fistulectomy 291
Fig. 5 3-D ultrasound demonstrates a trans-sphincteric anal fistula with hydrogen peroxide
enhancement of the tract
Fig. 6 MRI of the pelvis
demonstrates a horseshoe
fistula
Furthermore, patients who present with complex fistulas such as those with long
tracts, multiple external openings, anal inflammation or ulceration, and swollen
external anal skin tags should be evaluated for inflammatory bowel disease. A
292 M. A. Abbas
Fig. 7 Set-up for anorectal manometry and rectal compliance testing through an 8-channel catheter
colonoscopy is indicated for any patients with abnormal stool tests such as elevated
calprotectin, positive fecal immunochemical (FIT), and/or positive fecal occult
blood test (FOBT). When colonoscopy is performed, terminal ileum intubation is
highly advisable to check for any evidence of inflammation or ulceration of the small
bowel (Fig. 9).
3 Technique
3.1 Patient Preparation
All patients undergoing fistulectomy are advised to clean the rectum by administering two enemas at home 1–2 h prior to admission or upon arrival to the hospital.
Options for enema include warm tap water enema or a medicated enema containing a
salt such as monobasic sodium phosphate and dibasic sodium phosphate. A single
dose of intravenous antibiotics is administered within 1 h prior to incision. A
combination of ciprofloxacin and metronidazole or a cephalosporin and metronidazole is sufficient in most patients. Patient who undergo sphincter reconstruction as
part of their fistulectomy receive an additional 1 week of oral antibiotics.