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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1393_Библиотеки_им_академика_М_И_Перельмана.pdf
1 Surgery for Anorectal Abscess 11
Fig. 1.5 Type II extrasphincteric supralevator abscess from primary transsphincteric ischioanal
process. a Incorrect drainage internally can lead to b spontaneous decompression of the ischioanal
fossa. This intervention may produce either an F-type fistula as depicted (c) or an extrasphincteric
fistula (d). If the primary fistulous component is identified, a transsphincteric seton and drainage
catheter are employed. e If not identified, only a drainage catheter is placed (f)
12 A.E. Ortega et al.
Posterior type III extrasphincteric absces ses are managed similarly to a deep
postanal space infection with vertical sectioning of the anococcygeal ligament.
A supralevator cathet er may be placed in the setting of a large retrorectal abscess.
A transsphincteric seton through the primary fistulous trajectory is also an option in
this scenario (Fig. 1.6).
A type IV supralevator abscess has the deep postanal space as its primary focus
of infection. There is a secondary extension of the deep postanal space infection to
the ischioanal fossa. Both the deep postanal space and ischioanal infections contribute to the supralevator abscess simultaneously. Surgical treatment is directed at
the primary site of infection in the deep postanal space with counter drainage of the
involved ischioanal fossa (Fig. 1.7).
Abscesses presenting as a distinct fullness on the posterior wall of the rectum
also merit special consideration. Both posterior type I and type III abscesses should
be considered. The key to this differential diagnosis is inclusion or exclusion of the
deep postanal space as the primary infection (Fig. 1.8).
Preoperative imaging optimizes effective management of posterior supralevator
abscesses. Failure to include or exclude the deep postanal space as the primary
nidus of infection preoperatively compromises the surgical intervention. Albeit less
than ideal, this situation may be salvaged by the selective percutaneous aspiration of
the deep postanal space. The authors recommend a limited posterior midline cut
down to identify the anococcygeal ligament. A large bore needle is introduced in
the axis of the anal canal. It is important not to aspirate in the direction of the
coccyx. The latter scenario only confirms that a posterior retrorectal supralevator
abscess is in evidence. It does not identify involvement of the deep postanal space
(Fig. 1.9). A positive aspiration of purulence from the deep postanal space implies a
type III posterior extrasphincteric abscess requiring posterior exploration and
drainage. A negative aspiration is evidence of a type I posterior intersphincteric
abscess that requires internal (intrarectal) drainage.
Horseshoe presentations of anorectal abscesses are an important and pleomorphic group of infections. Circumanal inflammatory changes including cellulitis,
peau d’ orange, and fluctuance are characteristics. An anterior midline primary
gland infection is far less common than posterior processes. Anterior infection may
appear as horseshoes but tend to extend into the scrotal or labial tissues.
Posterior infections are far more common [14]. Treatment failures are as common as 50% [2]. Surgeons need to consider that any of the four posterior spaces
may be responsible for a horseshoe presentation: (1) superficial postanal, (2) deep
postanal, (3) supralevator, and (4) retrorectal. The authors use the term horseshoe
presentation rather than abscess because often the changes observed inflammatory,
i.e., cellulitis rather that frank fluctuance. These changes often reflect a deeper
seated infection. The most important feature of treatment of horseshoe presentations
1 Surgery for Anorectal Abscess 13
(a)
(b)
(Op
Fig. 1.6 Type III extrasphincteric supralevator abscess from a posterior midline process. a A
posterior midline incision is used to explore the postanal spaces. The superficial postanal space is
evaluated and then the anococcygeal ligament sectioned to enter the deep postanal space. Passage
through the pubococcygeus muscles allows evacuation of the supralevator component. b A
primary seton is placed through the internal opening if identified. Counter incisions can be made
over the ischioanal fossa bilaterally if needed. A retrorectal catheter can be inserted to decompress
the supralevator abscess
(Op
(Op
14 A.E. Ortega et al.
Fig. 1.7 Type IV
extrasphincteric supralevator
abscess from a primary
posterior midline process with
ischioanal component.
A posterior exploration (crypt
to coccyx) is required to
evaluate the postanal and the
supralevator spaces. The
posterior process can be
treated with catheter drainage
with or without a seton.
A counter incision is made to
drain the ischioanal
component externally.
Catheter drainage may be
implemented to address the
supralevator component in
this infection
is treatment of the primary focus of infection a priori. Moreover, not all inflammatory changes over the ischioanal fossae require counter drainage. The most
common mistake encountered in the treatment of horseshoe abscesses is the
bilateral treatment of the ischioanal fossae without addressing the primary midline
infection. For all these reasons, surgeons should consider preoperative imaging of
ischioanal infection as well as definitive treatment of the primary fi stulous component (Fig. 1.10).
The Role of Adjunctive Imaging
Imaging plays an important role in most areas of surgery. Its utility in the evaluation
and treatment of acute anorectal infections has largely been unrecognized. However,
four groups of patients have a clear benefit: (1) tetralogy of occult anorectal sepsis,
(2) differentiation of primary versus secondary ischioanal infections, (3) supralevator
abscesses, and (4) horseshoe presentations (Fig. 1.11). The tetralogy of occult
anorectal sepsis consists on the constellation of pain, sepsis, paucity of physical
finding, and/or a physical examination limited by hyperesthesia. Identification of the
primary site of an ischioanal abscess is relevant to its surgical management. Identification of the deep postanal space as the primary focus of infection can be a game
1 Surgery for Anorectal Abscess 15
Fig. 1.8 Retrorectal supralevator (Type I or III). a These abscesses may have normal topography.
b Fullness is encountered within the rectum posteriorly. c The ischioanal fossae are normal. This
clinical scenario may represent either a type III configuration (d) or type I configuration (f).
Computed tomography can assist in delineating the difference between type III (e) or type I (f)to
guide drainage
changer. Similarly, horseshoe presentations are benefited by identification of the
primary infection as well as differentiation between secondary abscesses versus fat
stranding (cellulitis) and phlegmon (lymphedema/lymphatic obstruction). The former require surgical drainage a priori while the latter observations may not. These
16 A.E. Ortega et al.
Fig. 1.9 Evaluation of retrorectal abscesses without preoperative imaging. a A posterior incision
is made with identification of the anococcygeal ligament. b A needle is inserted through the
ligament into the deep postanal space. Care should be taken to advance in a trajectory parallel to
the anal canal. c Purulence from the deep post anal space confirms a type III abscess and further
external exploration and drainage should be undertaken. A negative aspiration implies a type I
intersphincteric abscess and intrarectal drainage should be performed
are difficult distinctions in the purely clinical context. Finally, supralevator abscesses
require the evaluation of three spaces: (1) supralevator, (2) ischioanal, and (3) deep
postanal. Misdiagnosis of a primary deep postanal abscess associated with a
supralevator component is the most important cause of treatment failures in this
setting.
1 Surgery for Anorectal Abscess 17
Fig. 1.10 Horseshoe presentations may occur in multiple potential spaces including anterior,
superficial postanal, deep postanal, supralevator, and retrorectal. Preoperative imaging can assist in
identifying the spaces involved
Fig. 1.11 Indications for multi-plane reconstruction imaging with computed tomography in
anorectal infections
18 A.E. Ortega et al.
Each of the predominant imaging modalities has its proponents. Ultrasound is
interesting because of its cost and portability. The discomfort associated with a
transanal transducer is limiting. Magnetic resonance imaging is useful in the
evaluation of deep-seated and multiple space infections. It is relatively limited by its
availability. Multi-plane reconstruction computer tomography (MPR CT) is
emerging as an important modality for potentially complex anorectal infections. It
reliably identifies deep postanal space abscesses. Moreover, it is useful in discriminating between abscess and pro-inflammatory changes observed on physical
examination (cellulitis and lymphatic alterations).
Preoperative imaging should be considered indispensible in the setting of suspected abdominopelvic processes and supralevator presentations. The authors do
not support imaging all patients. However, it is clear that a systematic approach to
the history and physical examination helps identify patients harboring complex,
multi-space infections who may benefit from adjunctive imaging.
Conclusions
Anorectal infections are a common problem treated by a variety of medical practitioners since antiquities. Historically based dogma is still pervasive. Optimal
outcomes rely on a thorough systematic history and physical examination.
Adjunctive imaging has an increasingly important role in selected clinical settings.
The natural history of acute anorectal infections inevitably forming chronic anal
fistula requires scrutiny. Fortunately, complex fistulas are avoidable when complex
abscesses are appropriately evaluated and treated surgically.
Fournier’s Gangrene Complications, Prevention, and Treatment
Etiology
Ariane M. Abcarian and Herand Abcarian
Fournier’s gangrene is a necrotizing soft tissue infection involving the perianal and
ischiorectal areas, perineum, genitalia, and groin with occasional spread to the
lower abdominal wall, thighs, and lower back. The disease was originally described
by Jean Alfred Fournier in 1883 and was considered uniformly fatal [15]. In the
recent years, two alternative terms have been employed:
“Synergistic gangrene” refers to multiple species of bacteria involved in the
pathology of the disease and “necrotizing fasciitis” refers to common involvement
of various muscular fascias in the necrotizing process. Fournier’s gangrene must be
differentiated from myocutaneous necrosis caused by Clostridium species, which
requires different treatment.
1 Surgery for Anorectal Abscess 19
Anorectal and urinary tract infections are very common, however, it is unclear
why in some patients a seemingly minor septic process progresses to a
life-threatening necrotizing infection. It is thought that obliteration of distal arterial
disease caused by diabetes mellitus or an immunocompromized host (e.g., AIDS,
chemotherapy, or immunosuppressive thera py) allow the rapid growth and spread
of multiple bacterial species leading to tissue necrosis hence the term “synergistic
gangrene.” Understanding the contributory or the underlying disease process is
critical in the choice of appropriate treatment to prevent a fatal outcome.
The point of entry of the invasive bacteria may be in the lower gastrointestinal
tract or in the urogenital system. Anorectal infections of cryptoglandular origin
have been implicated and a common finding of a fistula in Fournier’s gangrene
lends credence to this theory [16]. Pelvic sepsis secondary to rubber band ligation
of hemorrhoi ds are forms of the same pathologic process [ 17, 18]. Necrotizing
sepsis following conventional hemorrhoidectomy is rare unless the patient is
severely immunocompromized [19].
Urogenital tract is the other important point of entry. Instrumentation such as
urethral catheterization, dilation, cystoscopy, and at times a simple urinary tract
infection may be the initiating factor [20, 21]. Immune compromise whether due to
acquired immunodeficiency disease (AIDS), chemotherapy or immunosuppression
from transplantation may be a contributing factor in the rapid spread of the septic
process [18, 22, 23].
A very important extensive case series was reported by Stephens et al. [24].
They compared the difference in etiology and clinical presentation of 449 cases of
Fournier’s gangrene in historical (1964–1978) era versus the “current” (1979–1988)
period. The average age was 50 years and gender strongly favored men (M/F ratio
of 86% vs. 14%). The most common etiologic factor was colorectal (33%) and
genitourinary (21%). In 26% no source could be identified and were labeled
idiopathic. The morbidity was 22% with significant unfavorable results seen in
colorectal disease (mortality 33%) [24].
Symptoms and Signs
The presenting symptoms of Fournier’s gangrene are pain, swelling, and discharge
of pus. Appearance of a “black spot” indicates the presence of gangrene and
impending spread along anatomic (Fig. 1.12) planes [25].
Cellulitis and fluctuation may be palpable to a variable distance from the main
swelling (Fig. 1.13).
Additional findings include fever, elevated WBC with left shift, and severe
hyperglycemia signifying uncontrolled diabetes mellitus.
Culture of pus or biopsy of margins of infected tissue usually yields mixed flora
including streptococcus, staphylococcus aureus, bacteroides, klebsiella, E. coli,
proteus, enterococcus, peptostreptococcus, and citrobacter with the highest concentrations seen in diabetics [20]. In addition to the usual aerobes and anaerobes,
Clostridium species may also be found in bacteriologic specimens [25].
20 A.E. Ortega et al.
Fig. 1.12 Typical Fournier’s
gangrene with central “black
spot” and bullae
Fig. 1.13 Extension of
Fournier’s gangrene along
tissue planes to the buttock
and thigh
Principals or Treatment, Prevention of Complications:
1. Frequent Surgical debridement
2. Broad spectrum antibiotics
3. Control of associated disease
4. Fecal/Urinary Diversion
5. Supportive care (Nutrition)
6. Hyperbaric Oxygen
7. Delayed wound care/reconstructive procedures.
1. Surgical debridement of all necrotic tissue down to normal bleeding tissue is
essential in the treatment of Fournier’s gangrene. Extensive debridement should
be undert aken without consideration to form or function or subsequent reconstruction. Attempts to salvage questionably viable tissue is to be condemned. The