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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1520_Библиотеки_им_академика_М_И_Перельмана
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390
S. Maslekar and D.G. Jayne
found in young or middle-aged women, in whom there is often a limited response to
bulking agents or laxatives. It is characterized by a lack of urge to defecate with delayed
colonic transit on scintigraphy or radiopaque marker studies. Obstructed defecation is
used to defi ne a group of conditions which present with a normal desire to defecate but
an inability to satisfactorily evacuate the rectum. Symptoms include diffi cult or pro-
longed attempts to defecate with straining, incomplete, fragmented evacuation, the need
for perineal support or digitation to initiate defecation, anorectal discomfort, and occa-
sional fresh bleeding. The condition may be associated with a mechanical outlet obstruc-
tion, such as internal rectal prolapse, rectocele, and descending perineum, or may be
functional due to uncoordinated contraction of the pelvic fl oor with dyssynergia.
Box 27.1: Types of Constipation
Primary
(a) Idiopathic slow transit
(b) Irritable bowel syndrome – constipation predominant
(c) Obstructive defecation syndrome
Secondary
(a) Congenital – Hirschsprung’s disease, imperforate anus, anorectal atresia
(b) Metabolic – diabetes, hypokalemia, hypomagnesemia, hypercalcemia,
hypothyroidism, hyperparathyroidism
(c) Psychological – abuse (psychological, physical, sexual), eating disorders,
affective disorders, pelvic pain syndromes
(d) Neurological – spinal cord injury, multiple sclerosis, Parkinson’s disease,
aganglionosis (Chagas’ disease), pseudoobstruction
(e) Myopathic – systemic sclerosis, amyloidosois
(f) Drugs – opiates, ferrous supplements, tricyclics, diuretics, antipsychotics,
anticholinergic drugs, antiparkinson medication
(g) Others – dehydration, immobility, pregnancy, postoperative
Case Scenario
A 29-year old lady presents in your clinic with a history of constipation. She
has been tried with various laxatives, but her bowels are working once every
2 or 3 weeks. She has been admitted for manual evacuation on two occasions
in the past 6 months, and now both she and her doctors are desperate for
help.
You have carried out transit marker studies that show she has markers through-
out the colon on day 5. A defecating proctogram showed a small rectocele
<2 cm with no evidence of an intussusception. Anorectal physiology sug-
gested a hyposensitive rectum with low compliance.
What treatments would you consider?
391
27 The Management of Constipation
In this chapter, we will concentrate on the surgical options available for slow
transit constipation and obstructed defecation.
27.2 Investigations
Details about relevant investigations are discussed in Chap. 26 . With regard to the
treatment of constipation, particularly in those with obstructed defecation, defecat-
ing proctography is essential. It is useful therefore to provide a brief description of
the commonly encountered defecographic abnormalities (Fig. 27.1 ). These anatom-
ical entities may exist in isolation, but in severe obstructive defecation are frequently
found in combination.
A rectocele is a herniation of the anterior rectal wall through the rectovaginal sep-•
tum, producing a bulge in the vagina. It is a common defecographic fi nding being
present in some 20% of asymptomatic patients [ 1 ] . Rectoceles greater than 2 cm
are considered abnormal [ 1 ] . Symptoms occur due to trapping of feces within the
rectocele, which gives rise to a feeling of incomplete evacuation. Digital pressure
on the posterior vagina wall to control the rectocele often aids evacuation.
Intussusception is the invagination of the rectal wall during straining and defeca-•
tion. It may be classifi ed as follows [ 2 ] :
Grade 1: high rectorectal intussusception
Grade 2: low rectorectal intussusception
Grade 3: high rectoanal intussusception
Grade 4: low rectoanal intussusception
Grade 5: external rectal prolapse
Rectoanal intussusception can obstruct the anal canal, requiring digitation via
the anus to initiate evacuation. It frequently accompanies rectocele formation, in
which case, it can lead to sequestration of stool in the rectocele, resulting in
incomplete evacuation and fragmented defecation.
Enterocele, sigmoidocele, and peritonocele are herniations of abdominal viscera •
into the deep pouch of Douglas. They are most commonly seen at the end of
evacuation with excessive straining and occur in 17–37% of patients [ 3, 4 ] . In
extreme cases, an enterocele may protrude through the anus along with a rectal
prolapse. In many cases, it is not clear whether an enterocele/sigmoidocele actu-
ally causes obstruction or is a compensatory mechanism to excessive perineal
descent, which increases rectal pressure and aids evacuation.
Solitary rectal ulcer syndrome (SURS) is characterized by chronic ulceration, usually •
of the anterior rectal wall (see Chap. 29 ). If an anatomical defect can be demonstrated
on proctography, it is usually that of intussusception or puborectalis paradoxus.
In descending perineum syndrome, pelvic fl oor descent is quantifi ed on proctogra-•
phy by its movement relative to the pubococcygeal line both at rest and during strain-
ing. Descent greater than 2 cm at rest is deemed to be abnormal [
4 ] . It is regarded as
a general marker of global pelvic fl oor weakness and is frequently associated with
enterocele/sigmoidocele. It is estimated that 50% of women have some degree of
genital prolapse, of whom 10–20% are symptomatic and this increases with age.
392
S. Maslekar and D.G. Jayne
27.3 Conservative Management of Constipation
27.3.1 General Measures (Box 27.2 )
These include increasing fi ber consumption, physical activity, increased fl uid con-
sumption, and behavioral changes to toileting practices. Some 85% of the patients
a
b
Fig. 27.1 Defecating
proctogram ( a ) at rest, ( b ) on
straining. Typical features
seen in a patient with
obstructed defecation include
perineal descent on straining
with the vagina occupying a
horizontal position, and
formation of a rectocele and
internal rectal prolapse. An
enterocele (not shown) may
be present descending into
the pouch of Douglas (No
copyright required)
393
27 The Management of Constipation
with simple constipation will respond to such measures [ 5 ] . Furthermore, increasing
fl uid intake to 1.5–2 L/day has been shown in a randomized clinical trial (RCT) of
chronic constipation to increase stool frequency and decrease the need for laxative
in individuals already consuming a high-fi ber diet [ 6 ] .
Increased physical activity also seems to be helpful [ 7 ] . The underlying mechanism
of action remains unclear but may relate to enhanced motor activity caused by improved
blood fl ow or hormonal activity, or even the mechanical effects of exercise on the gut.
27.3.2 Drug Therapy (Box 27.3 )
Box 27.2: Interventions for Constipation
Intervention
Example
General measures
Diet
Physical activity
Fluids
Behavioral changes
Drugs Laxatives
Retrograde colonic lavage Peristeen system
Biofeedback EMG/manometric feedback
Sensory retraining
Surgery Sacral neuromodulation
ACE procedure
Colonic resection
Ileostomy
STARR
Laparoscopic ventral rectopexy
Box 27.3: Available Drug Therapy for Constipation
Type of laxative Mechanism of action Examples
Bulking agents Increase stool bulk
Ispaghula husk
Bran
Stimulant laxative Increases motility Senna
Increases secretion Bisacodyl tabs/suppositories
Glycerin suppositories
Stool softener Softens stool Liquid paraffi n
Lubricates evacuation Arachis oil
Docusate
394
S. Maslekar and D.G. Jayne
Bulking agents are organic polymers that retain water in the stool. By adding water
and additional solid material to stool, these agents may improve symptoms of con-
stipation. Side effects are mild. Bloating is common as several agents undergo bac-
terial fermentation in the colon, thereby producing gas.
Examples include psyllium husk which is the outer coat of the psyllium seed
(known in India as ispaghula seed), methylcellulose (a hydrophilic plant derivative),
and bran (the outer coat of grain). Based on low- to intermediate-quality RCTs,
psyllium appears to improve stool frequency and consistency [ 8 ] . Trials on methyl-
cellulose and bran are limited and of poor quality. Whether they have any benefi t
over placebo or other medications remains controversial [ 9 ] .
Stimulant laxatives increase colonic motility and secretion, and induce a more pre-
dictable call to defecate. The most common stimulants are the anthraquinones (e.g.,
senna derivatives), which are naturally occurring colonic stimulants. When taken on a
chronic basis, they give rise to “melanosis coli,” the dark-brown pigmentation of the
colonic mucosa observed at endoscopy. Bisacodyl is a synthetic stimulant laxative
available in oral and suppository forms. Glycerine suppositories stimulate rectal evac-
uation and may be of particular value in those with obstructed defecation. Although
four RCTs exist comparing the effect of stimulant laxatives on constipation, the poor
study design means that no recommendations as to their use can be made [ 8 ] .
Stool softeners include docusate sodium and liquid paraffi n. They have little effect
in isolation and often need to be used as an adjunct to a stimulant laxative. Rectal
preparations such as an arachis oil enema (derived from peanut oil) are useful to
relieve rectal impaction. Although RCTs have looked at the effect of stool softeners
on constipation, the data is insuffi cient to draw any meaningful conclusions [ 10 ] .
Osmotic laxatives can be divided into two groups: (1) inorganic salts and (2)
organic sugars or alcohols. The former include magnesium salts; the latter include
lactulose. All are poorly absorbed from the gut and lead to osmotic fl uid retention
within the lumen. Polyethylene glycol (PEG)–based polymers have a more consis-
tent osmotic effect. Generally, they are used for bowel preparation but can also be
used in chronic constipation. Their side effects include colicky pain and dehydration.
Two systematic reviews of medical therapies for chronic constipation have concluded
that there is good evidence supporting the use of polyethylene glycol [ 8, 11 ] .
Type of laxative Mechanism of action Examples
Osmotic laxative Increase secretion Magnesium salts
Inorganic salt Movicol
Klean prep
Organic sugar/
alcohol
Lactulose
5HT-4 agonist Stimulates cholinergic
nerves
Prucalopride
Box 27.3 (cont.)
395
27 The Management of Constipation
New pharmacological agents include secretagogues, such as lubiprostone, and
prokinetic agents, such as prucalopride. Prucalopride acts as a partial 5HT-4 ago-
nist and stimulates the excitatory cholinergic nerves to both the small and large
bowel. It has been shown to accelerate both small and large bowel transit and to
improve bowel function and quality of life in chronically constipated patients
[
12 ] . Recently, published NICE guidance recommends its use in women who
have failed at least 6 months of laxative therapy, having tried at least two types of
laxative [ 13 ] .
27.3.3 Retrograde Colonic Lavage
Retrograde colonic lavage offers an additional treatment strategy in patients with
constipation resistant to conservative management. Irrigation alters the consistency
of stool and provokes the desire to defecate, thereby increasing the defecation fre-
quency [ 14 ] .
Patients normally use tap water to self-irrigate using either an Irrimatic pump
(Biotrol
®
, Braun, Melsungen, Germany) or an irrigation bag (Braun). Koch et al.
[ 14 ] prospectively studied colonic irrigation for constipation and found that although
major improvement occurred in only three out of ten patients, quality of life
improved in all ten patients. Only a few studies have assessed retrograde colonic
irrigation, and all reported a benefi cial effect ranging from 19% to 79% [ 15, 16 ] .
The procedure also requires considerable self-motivation and takes a signifi cant
time. Hence, there is a considerable dropout rate; up to 50% of patients will cease
treatment [ 14 ] . Nevertheless, the procedure is safe, minimally invasive, and has only
minor side effects and therefore is a useful conservative therapy.
27.3.4 Biofeedback Therapy
The term biofeedback therapy encompasses a variety of modalities aimed at increas-
ing patient awareness regarding bowel function in an attempt to alter defecatory
habits. Computer-aided feedback about sphincter and pelvic fl oor relaxation is uti-
lized with various biomarkers, including surface EMG with visual feedback and
intraluminal manometry with water-perfused or solid-state catheters. Sensory
retraining with intrarectal balloon distension may be useful in those patients with
poor rectal fi lling awareness or uncoordinated abdominal and pelvic fl oor muscle
recruitment.
It is impossible to say which technique of biofeedback is most effective.
Although there are four randomized controlled trials comparing different bio-
feedback techniques, the heterogeneity of the interventions, participants, and
outcome measures and the methodological weaknesses of these trials do not
allow strong conclusions to be drawn [ 17 ] . Whatever the technique, several
396
S. Maslekar and D.G. Jayne
prospective trials suggest that it is effective in obstructed defecation caused by
anismus. Three randomized controlled trials comparing biofeedback with pla-
cebo [ 18, 19 ] or laxatives [ 20 ] for patients with anismus have shown a signifi cant
benefi t with biofeedback. Although several studies have suggested that biofeed-
back can help patients with slow transit constipation, there is a lack of robust
evidence, and a placebo effect cannot be excluded. Any benefi t appears to be
dependent upon patient participation, with a decline in effi cacy observed on lon-
ger follow-up [
17 ] .
27.4 Surgical Options for Slow Transit Constipation
(Box
27.4 )
27.4.1 Sacral Nerve Modulation
Sacral Nerve Modulation (SNM) is increasingly used in the treatment of slow tran-
sit constipation. In a prospective study at fi ve European sites, 62 patients with slow
and normal transit constipation who failed conservative measures underwent a trial
of SNM, of whom 45 progressed to a permanent implant with a success rate of 87%
[ 21 ] . After a median 28 months’ follow-up, defecatory frequency increased from
2.3 to 6.6 evacuations per week and the Cleveland Clinic Constipation Score
decreased from 18 to 10. Colonic transit normalized in half of those with baseline
slow transit. Several studies have confi rmed these fi ndings to a variable extent [ 22 ] ,
Box 27.4: Surgical Options for the Treatment of Constipation
Slow Transit
Constipation
– Neuromodulation
– Irrigation – antegrade (ACE) or
retrograde
– Stoma - ileostomy
– Resection – segmental or
colectomy with ileorectal
anastomosis
Obstructed
Defaecation
Anismus – Botox
Rectocele – Tranvaginal repair +/− mesh
– Transperineal repair +/− mesh
– Transanal repar +/− mesh
– STARR
Intussusception – Internal Delormes - STARR
– Laparoscopic ventral rectopexy
397
27 The Management of Constipation
although interpretation of the data is hindered by a lack of homogeneity in defi nition
and patient selection. The mechanism of action remains unclear, but an increase in
pancolonic propagating pressure waves has been observed [ 21 ] . It seems likely that
SNM produces a real rather than a placebo effect as double-blind, placebo-con-
trolled [
23 ] , crossover studies have demonstrated a marked difference in symptoms
when the stimulator is switched off. The advantage of SNM is the ability to perform
a relatively simple and cheap test stimulation, which is largely predictive of out-
comes should the patient proceed to a permanent implant.
27.4.2 Antegrade Colonic Enema
The antegrade colonic enema (ACE) is an option for severe constipation with or
without overfl ow incontinence and may be a preferred option to a stoma or colec-
tomy. Malone fi rst described the technique using the reversed appendix as the conduit
with the amputated tip tunneled into the cecum as the continence mechanism [ 24 ] . If
the appendix is unavailable, cecostomy can be carried out using more complex bowel
plasty techniques.
The reported results are variable and appear to be worse in adults as compared to
children [ 25 ] . About one-third of adults required major revisional surgery, one-third
required minor revisional surgery, and 50% required reversal after a median of
3 years [ 25 ] .
As with colonic irrigation, the ACE procedure requires considerable self-moti-
vation and time. Patients spend on average 50 min every 1–2 days irrigating the
stoma [ 26 ] . Over 60% suffer with side effects from the washout (painful catheter-
ization, chills, nausea, tiredness, anal skin problems, and rectal bleeding) or regu-
lar refl ux of feces through the stoma. Despite this, satisfaction rates long term for
those that continue to use the ACE are high, probably because of the discrete
nature of the stoma; most patients required only a plaster or bandage to cover the
opening [ 26 ] .
27.4.3 Resectional Surgery
Colectomy is usually the fi nal resort for severe chronic constipation when all other
methods have failed. The surgical options include subtotal colectomy with ileorec-
tal anastomosis, segmental colectomy, and stoma formation. Colectomy for STC
was popular in the 1990s but has gradually fallen out of favor due to diffi culties in
patient selection, poor functional outcomes, and the potential for serious complica-
tions. However, it is generally agreed that colectomy may have a limited role in
highly selected patients with severe constipation.
398
S. Maslekar and D.G. Jayne
Selection criteria for colectomy have been refi ned to some extent over the past
20 years and include a range of clinical and physiological criteria. Abdominal pain and
bloating rarely improve with surgery [ 27 ] , and similar poor results are observed in
patients with coexisting psychological disturbances [
28 ] . The ideal selection criteria
include proven slow colonic transit with normal gastric and small bowel transit, normal
rectal sensation, and an ability to evacuate effectively [
29 ] . The role of colonic manom-
etry in patient selection for colectomy remains experimental [ 22 ] . Constipated patients
have higher depression, hypochondriasis, and hysteria scores compared with controls.
In a long-term follow-up study, overall failure and permanent stoma rates were signifi -
cantly higher in patients with psychological disturbances [ 28 ] . Psychotherapy or psy-
chotropic medications have not been shown to improve surgical outcomes.
Published patient satisfaction or success rates in the region of 80% have been
reported, with an improvement in bowel function over time. However, recurrent con-
stipation is problematic with published rates ranging from 0% to 46% [ 27 ] .
Alternatively, diarrhea may be as troublesome as the original constipation. Attempts
to mitigate postcolectomy diarrhea by means of cecorectal anastomosis result in a
high incidence of recurrent constipation. There is scarce data on the long-term follow-
up of patients undergoing subtotal colectomy with ileorectal anastomosis. One study
reported that the median stool frequency was 3/day (range 1–14) in 40 patients fol-
lowed up for a median of 95 months [ 27 ] . Seventeen percent were using medications
(8% for constipation and 9% for diarrhea). Persisting abdominal pain occurred in 40%
of patients, although there was signifi cant improvement in the severity of the pain.
Segmental colectomy has been tried as an alternative to subtotal colectomy in those
patients with proven segmental delay, but the evidence in support of this approach is
limited [ 30 ] . Laparoscopic colectomy offers the benefi t of less postoperative pain, better
cosmesis, shortened hospital stay, and earlier return to normal activities. One retrospec-
tive study compared 17 patients undergoing open colectomy with 7 patients undergoing
laparoscopic colectomy and found that the laparoscopic group was more satisfi ed with
the cosmetic outcome but had longer operation times and more complications [ 31 ] .
Restorative proctocolectomy with ileoanal pouch reconstruction has been pro-
posed, but the evidence for this is poor. In the series reported by Hasegawa et al., all
fi ve patients underwent excision of their pouch for persistent constipation [ 32 ] .
Stoma formation may have a role as either a defi nitive procedure or as a prelude
to colectomy. Initial ileostomy may select those patients with normal small bowel
transit who are likely to have a better outcome following subtotal colectomy.
A signifi cant number of patients with STC ultimately end up with a stoma. In a long-
term follow-up study (median 7 years), Hasegawa et al. noted that 14 of 61 patients
(23%) who initially underwent colectomy eventually had a permanent stoma [
32 ] .
27.4.4 Obstructed Defecation Syndrome
Approximately 50% of patients with constipation suffer from obstructed defecation,
with or without slow transit. Obstructed defecation syndrome (ODS) is an umbrella
399
27 The Management of Constipation
term used to describe an inability to satisfactorily evacuate the rectum. It incorpo-
rates a range of mechanical abnormalities including internal rectal prolapse (intus-
susception), rectocele, sigmoidocele, enterocele, and descending perineum syndrome
(Fig.
27.1 ), as well as anismus or pelvic fl oor dyssynergia.
Patients being considered for surgical treatment of ODS should be fully evalu-
ated in order to try to identify those with symptoms due to a correctable mechani-
cal cause from those with a nonsurgically correctable cause, such as anismus.
Even then, surgery should be considered only when conservative measures have
failed and quality of life is compromised. Assessment of other pelvic organ pro-
lapse should be undertaken as appropriate, which may be present in some 30–40%
of patients.
There has been renewed interest in surgery for obstructed defecation in the last
decade with the introduction of stapled transanal rectal resection (STARR) and lap-
aroscopic ventral rectopexy, as well as innovative but less established techniques
such as the EXPRESS procedure [
33 ] .
27.5 Surgical Options for Obstructed Defecation (Box 27.4 )
27.5.1 Botox Therapy for Anismus
After failure of biofeedback, 50–75% of patients with anismus may benefi t from
botulinum toxin injection into the puborectalis muscle. Ultrasound guidance may
help to precisely locate the injection site. Repeat injections may be required as many
patients who initially respond, subsequently relapse [ 34 ] .
27.5.2 Rectocele Repair
There are essentially four methods of repair detailed below. The overall success
rates are universally reported at around 80%. However, published outcomes are dif-
fi cult to evaluate because reported symptoms are heterogeneous, the extent of pre-
operative evaluation is variable, and the criteria of success are inconsistent and ill
defi ned [ 35 ] .
27.5.2.1 Transvaginal
The transvaginal approach is favored by the gynecologists. The procedure essentially
consists of repair of the rectovaginal fascia and plication of the levators. Access is
superior to the transanal approach, but there may be a signifi cant incidence of dys-
pareunia (up to 33%), and the procedure does not correct any posterior rectal problem
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