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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1393_Библиотеки_им_академика_М_И_Перельмана.pdf
Surgery for Anorectal Abscess
Adrian E. Ortega, Timothy F. Feldmann, Ariane M. Abcarian
and Herand Abcarian
Complications of Surgery for Cryptoglandular Anorectal Infections
Adrian E. Ortega and Timothy F. Feldmann
Introduction
Like many of the writers since antiquities, Hippocrates believed that anorectal
infections resulted from traumatic activities including horseback riding and rowing.
He referred to them as “tubercles,” and wrote: “Whenever you observe any such
tubercle forming, incise this as soon as possible during the unconcocted state before
suppuration into the rectum occurs.” [1].
Late nineteenth and early twentieth century surgical scholars codified numerous
elements pervasive in the current day practice of proctology. Namely, drainage is
directed over the area where the abscess points. Cruciate incision with resection of
1
A.E. Ortega (&)
LAC+USC Medical Center, University of Southern California,
Clinic Tower Room, 6A231-A, 1200N. State Street, Los Angeles, CA 90033, USA
e-mail: sccowboy78@gmail.com
T.F. Feldmann
Capital Medical Center, 3900 Mall Dr. SW, Olympia, WA 98502, USA
A.M. Abcarian
Division of Colon and Rectal Surgery, John H. Stroger Hospital
of Cook County, 1900W. Polk Street, Chicago, IL 60612, USA
H. Abcarian
Division of Colon and Rectal Surgery, University of Illinois at Chicago,
840 S. Wood Street, Chicago, IL 60612, USA
© Springer International Publishing AG 2017
H. Abcarian et al. (eds.), Complications of Anorectal Surgery,
DOI 10.1007/978-3-319-48406-8_1
1
2 A.E. Ortega et al.
the skin edges is required to prevent premature wound closure and persistent sepsis.
Loculations within the abscess cavity should be broken up aggressively for the
same reason. Packing is indicated in order to establish hemostasis within the
wound. Primary fistulotomy at the time of incision and drainage is ill advised since
most acute abscesses do not result in chronic fistula and may be harmful vis-à-vis
iatrogenic fistula and incontinence. Finally, fistula is a non-preventable component
of the natural history of anorectal infections in a small proportion of patients.
The current understanding of anorectal infection suggests that all the afore-
mentioned concepts are associated with their own untoward consequences and
should be reconsidered. This chapter identifies common and uncommon complications associated with the surgical treatment of acute cryptoglandular anorectal
infections (Part I). The authors offer evidence-based as well as novel perspectives
focusing on the clinical strategies required for the prevention of surgical misadventures and suboptimal outcomes (Part II).
Part I: Complications
Neurovascular Injuries
While bleeding may occur with any surgical procedure, hemorrhage is distinctly
uncommon in incision and drainage of anorectal abscesses. Generalized oozing
occurs particularly in deep-seated abscesses. It also usually resolves following
evacuation of the purulent material and irrigation. However, the practice of
breaking up loculations with a clamp typically in the ischioanal fossa or higher may
be associated with injury to either or both inferior rectal or inferior pudendal vessels
and nerves. Gentle exploration with the surgeon’s index finger is preferred. Frank
hemorrhage may be associated with a pseudoaneurysmal rupture of an injured
blood vessel within an abscess cavity, but is an exceedingly rare event. The incidence of postoperative bleeding in one large series was only 0.6% [2]. Similarly
aggressive packing of the wound is associated with delayed healing and potential
sphincteric injury probably secondary to nerve injury. Light packing or no packing
is generally preferred [3].
Persistent Sepsis
Persistent sepsis is the failure to resolve an acute infection following a surgical
intervention. The largest reported series of 500 consecutive cases examined early
reoperations for perirectal abscess. Onaka et al. cites an overall incidence of 8.2%
of persistent sepsis. In their estimation, these failures were secondary to incomplete
drainage (4.6%) , missed loculations within the abscess (3.0%), and missed
abscesses (0.6%). Albeit infrequent, persistent sepsis is a preventable complication
[2] (Fig. 1.1).
The root cause for persistent sepsis following a surgical drainage procedure is
multifactorial. In the series above, infections classified as perianal had the highest
rate of reoperations followed by ischiorectal, intersphincteric and supralevator
abscesses. The observation is counter-intuitive. However, it is not difficult to
understand. Many surgeons, particularly the less experienced focus much attention
1 Surgery for Anorectal Abscess 3
Fistula in formation
Fistula in formation
Persistent
Persistent
Bilateral
Bilateral
Cellulitis
Cellulitis
Bridging draining seton
Bridging draining seton
through the
through the
superficial postanal space
superficial postanal space
(Penrose drain)
(Penrose drain)
Fig. 1.1 Persistent sepsis and a fistula in formation are in evidence. While both ischioanal fossae
were incised and connected with a draining penrose seton communicated through the superficial
postanal space, the deep postanal infection was not addressed by this intervention
on the obvious topographic appearance of the perianal region. This tendency
facilitates overlooking important elements in the history and physical examination
of the patient. Most anorectal infections appear simple. However, they may represent the “tip of the iceberg” of a more complex infection.
The authors speculate on the legitimacy of the concept of loculated abscesses. It
is a difficult concept to prove objectively. Multiple space infections, however, are
well documented. Examples include secondary ischioanal infections from a deep
post anal space or supralevator space primary. Supralevators may also appear as a
perianal infection on topographic inspection.
While the percentage of persistent infections is relatively small, it is not a
diminutive topic in clinical practice. It is seen commonly in diabetic patients even
when appropriately drained. These patients often require a tincture of time on
antibiotics, glucose control and local wound care (sits baths). Ongoing sepsis is also
common in patients who undergo drainage of a secondary infection leaving the
primary septic focus undrained. When in doubt, it is best to image the patient and
proceed to the anatomically indicated drainage procedure in a formal operative
setting.
4 A.E. Ortega et al.
Progression of Sepsis
The concept of “pus under pressure” allows dissection along tissue planes and into
potential spaces. Cryptoglandular infections can also disseminate into the supralevator space through various routes as discussed in Part B. Once seeded, large
collections can propagate to the psoas muscle or along the paraspinal musculature.
The treatment of these complications must be control of the primary site of infection
and drainage of the infection itself. Necrotizing fasciitis is a relatively uncommon
complication of cryptoglandular disease seen in the setting of immunologically
challenged individuals [3].
Recurrent Abscess
Recurrent abscess is a common finding with cryptoglandular disease. 25–50% of
patients may experience recurrence of an abscess. Recurrence should be differentiated from persistent disease through a thorough history and delineation of the
patient’s symptoms. Without a symptom-free interval, the abscess was likely not
resolved from the initial treatment. True recurrent abscesses may or may not have
an associated anal fistula. Recurrent infection is distinctly less common following
definitive treatment of the abscess addressing the primary fistulous tract as compared to simple incision and drainage alone [4]. Definitive surgery also results in
fewer surgeries overall vis-a-vis simple drainage [5].
Delayed Wound Healing
The perineum is normally a very well vascularized field. Redundant blood supply
through the branches of the internal iliac arteries allow for excellent healing in most
circumstances. Despite the possible frequent contamination from stool, these
wounds will often heal quickly. Nutritional status and immune competence may
mitigate wound healing. Robust packing of wounds has been demonstrated to delay
wound healing [6]. Wounds rarely heal in the setting of previous radiation.
Occasionally, non-healing wounds may be seen in the context of an underlying
malignancy or osteomyelitis of a pelvic bone may be seen. Poorly optimized
patients with human immune deficiency virus may demonstrate poor wound healing. However, they are generally symptomatically benefited from anorectal surgical
interventions.
Wound Contraction Deformities
Contraction deformities or “step-offs” are the result of cruciate or vertical drainage
incisions. Neither of the previous has been show to prevent premature wound
closure. However, the effectiveness of radial incisions was reported to be 99.6% in
one large series [7]. Radial incisional drainage was first described by Ayers in 1886
specifically emphasizing the prevention of contraction deformities [8].
Iatrogenic Fistula
Fistula may form following an anorectal abscess in 5–85% of cases [9]. An
iatrogenic fistula can form following incorrect drainage of a complex abscess.
Examples include a suprasphincteric fistula secondary to external drainage of an
1 Surgery for Anorectal Abscess 5
intersphincteric supralevator abscess. Conversely, extrasphincteric fistula result
from internal drainage of an extrasphincteric supralevator abscess. Theoretically,
iatrogenic fistula may result from definitive treatment of the abscess and primary
fistulous trajectory simultaneously. However, the incidence of this latter complication is unknown. It is also important to note that complex fistula may form when
simple drainage is performed on multi-space infections. Spontaneous drainage of an
abscess can also produce complex fistulas.
Chronic Fistula
Conventional wisdom dictates that a certain proportion of patients with an acute
anorectal infection will progress to the chronic phase with an anal fistula. To what
degree a chronic fistula is preventable is not known. However, it is clear that
drainage with definitive treatment of its primary fistulous component is associated
with fewer operations subsequently for recurrent abscesses and fistula. The incidence of incontinence does not appear to increase with combined treatment [10].
Definitive treatment of infections involving the deep postanal space abscesses can
prevent horseshoe, hemi-horseshoe, suprasphincteric, and extrasphincteric fistulas
in most cases.
Incontinence
Anorectal infections and their treatment continue to put patients at risk for incontinence. Knoefel also note that recurrent infections are more likely to alter sphincter
function than fistulotomy with drainage than simple drainage alone [11]. Prior to
any intervention that may involve the sphincters, a surgeon should assess sphincter
function in both a subjective and objective fashion. The patient should be queried as
to their current function with control of stool and gas. Objectively the resting
pressure and squeeze pressure of the anorectal ring should be assessed. This does
not need to involve specific manometric testing but rather a digital exam by an
experienced practitioner. In the acute setting this may be impossible due to pain
from the infection. The physician can then document the perceived continence prior
to the infection. If treatment for fistula is to be undertaken, preoperative assessment
is essential prior to operative decision-making. The subjective portion of the
patient’s continence may then be less reliable due to leakage from the fistula. Many
patients may be unable to distinguish incontinence from fistula drainage in this
setting. In the current state of the art, alterations in continence may result from both
simple drainage as well a s definitive treatment of abscesses with the fistulous
components. Fortunately, it is an uncommon problem (1–2%) [10]. Moreover, these
alterations are generally limited to gas and liquid incontinence of the majority. Full
disclosure of the inherent risks, albeit small, is paramount in all cases.
Part II: Prevention Strategies
The prevention of untoward sequelae in the treatment of acute anorectal infections
begins with a systematic clinical approach. Pain is the most common symptom. Its
time in evolution and duration are important considerations. Rapid onset over a
short duration is commonly seen with perianal infections. This feature is thought to
6 A.E. Ortega et al.
be secondary to the dissection of pus through the tight fascial compartments of the
corrugator cutis extensions of the sphincter muscles out toward the skin at the anal
margin. Pain augmented on defecation is compatible with an intersphincteric
infection secondary to the dissection of pus between the internal and external
sphincters. Longer durations of symptoms favor infections occupying large spaces
like the ischioanal fossa or multiple spaces (e.g., supralevator abscesses). Tenesmus
and pain augmented with defecation are also characteristic of supralevator
processes.
Visual inspection of the perianal region is important. However, it needs to be
considered in the context of acute cryptoglandular obstruction as a chronologic
sequence of inflammatory changes. Cellulitis generally precedes lymphedema and
lymphatic obstruction. Fluctuance secondary to a frank abscess is a relatively late
event in this sequence. Therefore, clinicians should not over interpret obvious
topographic signs, as they may be harbingers of deeper seated infections. The
absence of obvious clinical signs suggests an occult anorectal infection. Submucosal, intersphincteric, deep post anal space and supralevator abscesses fall into this
category.
Digital rectal examination should also be systematic. Palpation of a boggy mass
above the sphincters is the sine qua non of supralevator processes. Submucosal
abscess begin in the anal canal extending proximally a short distance. Intersphincteric supralevators are palpable above puborectalis muscle. Bi-digital
examination with the examiner’s index finger within the rectum and thumb over
the ischioanal fossa identifies involvement of the latter space. Palpation of the anal
canal may reveal an area of induration or a divot associated with the site of the
primary cryptoglandular obstruction. Purulent discharge per anus has three possible
explanations: (1) decompression of the abscess at the primary crypt of origin;
(2) spontaneous decompression of a supralevator abscess into the rectum; and
(3) proctocolitis. When formal exploration of an abscess is contemplated, the
abscess should not be compressed until evaluation under anesthesia in order to
optimize one’s ability to identify the primary crypt and fistulous trajectory.
The natural history of anorectal infections is mucocutaneous necrosis and
spontaneous drainage by Providence unless intervened first by a competent
physician. Longstanding neglected infections upon spontaneous drainage may
produce undesirable consequences including complex fistula. Therefore, the time
honored concept of early drainage remains as an operant fundamental concept.
The tetralogy of occult anorectal sepsis consists of pain, evidence of infection, a
paucity of obvious physical findings and hyperesthesia often limiting the physical
examination. It is commonly associated with submucosal, intersphincteric, isolated
deep post anal and supralevator abscess. Imaging is invaluable in this setting with
the intent to treat formally in the operative room setting.
A Practical Approach to Anorectal Infections
Cryptoglandular infection propagates by three routes: (1) superficial, (2) intersphincteric, and (3) transsphincteric. Extrasphincteric refers to a supralevator
transsphincteric proces s. Superficial infections result in submucosal or subcutaneous
1 Surgery for Anorectal Abscess 7
abscess. They pose few problems if correctly diagnosed. While submucosal abscess
are generally associated with normal perianal topography, they are palpable within the
anal canal as a walnut-size soft and tender mass. Intersphincteric trajectories may
present as perianal, an abscesses confined to the anal canal or with proximal extension
as a supralevator abscess. Combinations in all three spaces are seen with an intersphincteric trajectory. Transsphincteric trajectories are the least common, but the
most problematic. In its simplest configuration, it results in a primary unilateral
primary ischioanal abscess. A posterior transsphincteric fistulous trajectory results in
a deep post anal space abscess. Abscesses in this location may be isolated with
negligible physical signs if seen early. However, they may propagate anterolaterally
to produce a secondary ischioanal abscess. Bilateral propagation from the deep post
anal space results in one important variant of a “horseshoe” presentation. Deep post
anal space infections can dissect between the leaves of the pubococcygeus muscles
that insert onto the sides of the coccyx. This trajectory produces a posterior extrasphincteric supralevator abscess. In its most unusual form, a deep post anal space
abscess can propagate to both the supralevator and ischioanal spaces. The secondary
ischioanal component can independently and simultaneously disseminate into the
supralevator space along the medial aspect of the fascia of the obturator internus
muscle. This scenario produces a combined extrasphincteric supralevator abscess
from a deep post anal primary and ischioanal secondary infection. Ortega and colleagues have proposed a novel classification of supralevator abscesses based on these
principles: type I intersphincteric, type II anterolateral extrasphincteric via the
ischioanal fossa, type III posterior extrasphincteric from the deep post anal space, and
type IV combined posterior and anterolateral extrasphincteric via the deep post anal
and ischioanal spaces simultaneously [12] (Fig. 1.2).
The correct diagnosis and treatment of supralevator abscesses require the evaluation of three spaces: (1) supralevator, (2) ischioanal, and (3) the deep postanal. It
is important to point out that more than half of supralevator abscesses of cryptoglandular origin have the deep postanal space as their primary site of infection.
Figure 1.3 demonstrates the diagnostic and treatment algorithm required for successful management of supralevator infections.
Simple superficial low infections pose few problems in the short and long term.
Deeper seated as well as infections occupying multiple spaces are distinctly different. The latter offer opportunities for the prevention of persistent, recurrent, and
chronic sepsis (i.e., complex anal fistula). Therefore, horseshoe presentations,
ischioanal, deep postanal, supralevator abscesses, and horseshoe presentations merit
special consideration.
Ischioanal infections are the second most common type of infection following
perianal abscesses. In contrast, their presentation is longer in evolution and their
size is greater in lateral extension. Few topographic signs may be present early in
their evolution. However , a palpable fullness between the examiner’s index finger
and thumb may be appreciated. In their most common later presentation, a large
area of cellulitis often extending several centimeters outside the anal margin
extending over the gluteal tissues may be seen. They are often drained as a bedside
procedure. This common practice merits reconsideration. Primary ischioanal
8 A.E. Ortega et al.
Fig. 1.2 Novel classification scheme for supralevator abscesses. Type I—Intersphincteric. Type
II—Extrasphincteric supralevator extension of a primary transsphincteric ischioanal abscess. Type
III—Posterior extrasphincteric supralevator extension from a primary deep post anal space
abscess. Type IV—Extrasphincteric supralevator extension from both the deep post anal space and
the ischioanal space simultaneously (unilateral or bilateral)
abscesses represent a direct transsphincteric process to one isolated fossa. Secondary ischioanal infections originate in the deep postanal space and then propagate
to one or both ischioanal fossae. This bilaterally may be symmetrical, asymmetrical,
or delayed. For all these reasons, the authors recommend ima ging of ischioanal
abscesses in order to facilitate definitive management. This strategy appears to be
most reasonable for the prevention of persistent and recurrent sepsis as well as
difficult chronic fistula in this context.
Primary ischioanal abscesses are approached either as a bedside or formal
operative procedure. Secondary ischioanal infections offer a unique opportunity for
definitive management in which persistent and recurrent infection can be minimized. The surgical approach to the deep postanal space entails a crypt to coccyx
midline incision. The anococcygeal ligament is sectioned vertically in its midline.
A transsphincteric seton may be placed through the primary posterior fistulous
trajectory.
The belief that supralevator abscesses are rare needs to be reconsidered.
Supralevator abscesses were identified in one large series in 9.1% of cases.
Therefore, while less common they comprise nearly one in ten crypt oglandular
1 Surgery for Anorectal Abscess 9
(1)
(2)
(+) SUPRALEVATOR
(3)
Supralevator
Space
(-) DEEP POST
ANAL SPACE
(TYPE I)
INTRARECTAL
DRAINAGE
(-) ISCHIOANAL
(+) DEEP POST
ANAL SPACE
(TYPE III)
Deep Post Anal Space
AND ISCHIOANAL SPACES
POSTERIOR
EXPLORATION
AND DRAINAGE
(+) ISCHIOANAL
(+) COMBINED
DEEP POST ANAL
(TYPE IV)
y
r
a
e
m
g
i
a
r
n
P
i
a
Dr
Secondary
Counter drainage
(-) DEEP POST
ANAL SPACE
(TYPE II)
LATERAL
EXTERNAL
DRAINAGE
Ischioanal
Space
Fig. 1.3 Algorithm for treatment of supralevator abscesses. Evaluation of three spaces is
required: (1) supralevator, (2) ischioanal, and (3) deep postanal. Their inclusion or exclusion
determines the correct intervention required to prevent recurrent or persistent sepsis as well
complex fistula
infections [13]. More than half have no obvious physical signs on visual inspection.
Palpation of a boggy mass within the rectum is the diagnostic sine qua non. More
than half of supralevator abscesses have the deep postanal space as their primary
site of infection.
Intrarectal drainage of a type I intersphincteric supralevator abscess is definitive
treatment. If the intersphincteric primary fistulous trajectory is identified, an internal
sphincterotomy incorporating it may be performed. It may be preferable to place an
intersphincteric seton in special cases including an anterior trajectory in a female or
a posterior midline trajectory in either gender. The latter diminishes the risk of
forming a posterior keyhole deformity that enables seepage of mucous subsequently
(Fig. 1.4).
Anterolateral type II extrasphincteric abscesses are drain ed external via the
ischioanal fossa with or without a transsphincteric seton through the primary fistulous trajectory. Because of the depth of the drainage tract, most surgeons place a
supralevator drainage catheter in the space. Once the space is collapsed several
weeks later, this catheter is withdrawn. Some surgeons make no effort in localizing
the primary fistulous trajectory thereby simplifying wound care with the single
catheter drain (Fig. 1.5).
10 A.E. Ortega et al.
Fig. 1.4 Type I intersphincteric supralevator abscess. a Incorrect external drainage through the
ischioanal fossa results in b a suprasphincteric fistula. c Correct internal drainage of the abscess
with an intersphincteric seton shown. d Alternative internal drainage in continuity with an internal
sphincterotomy demonstrated