Obstructed defecation syndrome (ODS) is a functional disorder leading to the sensing of outlet obstruction in the absence of any pathological findings. In this article, we also provide the etiology of acquired constipation. Constipation is a very common presentation by the patients of a practicing surgeon. Any constipation that defies the existing understanding merits consideration for its evaluation for ODS. Constipation can be of primary or secondary variety. After clinically excluding the usual causes of constipation and ruling out colonic motility disorders, specialised investigations like dynamic defecography help in further management of ODS.

1. Obstructed defecation syndrome

2. Review Article
Obstructed defecation syndrome
Brij B. Agarwal *
Vice Chairman, Professor & Senior Consultant, Department of Laparoscopic & General Surgery, GRIPMER & Sir Ganga
Ram Hospital, New Delhi, India
1. Introduction
Obstructed defecation syndrome (ODS) is a functional disor-
der leading to defecatory dysfunction that leads to sensing of
outlet obstruction in the absence of any pathological findings.
Constipation is a very common presentation by the patients
of a practicing surgeon. Any constipation that defies the
existing understanding merits consideration for its evalua-
tion for ODS. The constipation can be of primary or secondary
variety.
Three pathophysiological subtypes of primary constipation
have been described:
1. Constipation predominant irritable bowel syndrome (C-IBS).
2. Slow transit constipation.
3. Dys-synergic defecation.
Before proceeding to evaluate primary constipation, a
thorough history taking and examination must be undertaken
for all the known causes of secondary constipation.
2. Approach to rule out secondary constipation
Secondary constipation may be due to several factors
in isolation or combination. These may be lifestyle and
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x
a r t i c l e i n f o
Article history:
Received 16 July 2015
Accepted 22 July 2015
Available online xxx
Keywords:
Obstructed defecation syndrome
(ODS) prognosis
Constipation predominant irritable
bowel syndrome (C-IBS)
Wireless motility capsule (WMC)
Stapled Trans-Anal Resection
Rectopexy (STARR)
Rectocele
a b s t r a c t
Obstructed defecation syndrome (ODS) is a functional disorder leading to the sensing of
outlet obstruction in the absence of any pathological findings. In this article, we also provide
the etiology of acquired constipation. Constipation is a very common presentation by the
patients of a practicing surgeon. Any constipation that defies the existing understanding
merits consideration for its evaluation for ODS. Constipation can be of primary or secondary
variety. After clinically excluding the usual causes of constipation and ruling out colonic
motility disorders, specialised investigations like dynamic defecography help in further
management of ODS.
# 2015 Published by Elsevier B.V. on behalf of Indraprastha Medical Corporation Ltd.
* Tel.: +91 9810124256.
E-mail address: endosurgeon@gmail.com
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3. diet-related factors, medical drug intake-related, behavioral or
psychiatric factors, metabolic or endocrinal disturbances,
neurological, or other structural pathologies. A problem-
specific history taking and physical examination should be
performed in such patients (level of evidence IV: Grade of
recommendation B). These should proceed as shown in
Table 1. The drug intake history should include various drugs
as shown in Table 2.
3. Ruling out constipation predominant
irritable bowel syndrome (C-IBS)
Irritable bowel syndrome can be constipation-predominant,
diarrhea-predominant and alternating diarrhea–constipa-
tion presentation. Irritable bowel syndrome needs to be
excluded as per Rome II criteria. Rome II criteria define
irritable bowel syndrome as symptoms in absence of any
identifiable structural or metabolic disturbances to explain
the symptoms. The symptoms are abdominal discomfort/
pain of more than 12 weeks duration consecutively or
nonconsecutively in the last 1 year along with any two of
the following three features.
1. Symptoms are relieved by defecation/passage of flatus.
2. Onset of symptoms is associated with a change of stool
frequency.
3. Onset of symptoms is associated with change in stool form
in absence of laxative usage.
3.1. Ruling out dys-synergic defecation
In normal defecation there is increase in intrarectal pressure
(IRP) with simultaneous fall in intra-anal pressure. This recto-
anal pressure synergy leads to a propulsive rectoanal pressure
gradient (RAG). The pressure is estimated by rectal manome-
try.
There are four types of dys-synergic defecation as given in
Table 3.
3.2. Ruling out slow transit constipation
Slow transit constipation needs specialized investigation. It
can be suspected on having a clinical history of absence of
normal bowel urge that is experienced on either getting up in
the morning or after having a meal. If it is suspected, further
evaluation should be done. Assessment of the speed at which
stool moves through the colon provides objective measure-
ment of colonic transit. Colon transit time can be measured by
three methods.
1. Radio-opaque marker test: A single capsule with 24 plastic
markers is given for patient to ingest followed by a plain
abdominal radiograph on day 6 (120 hrs' later). Retention of
atleast 20% markers or more than six markers after 120 hrs
is indicative of slow transit constipation, as shown in Fig. 1.
2. Radioisotope scintigraphy provides non-invasive quantita-
tive evaluation of total and region colonic transit. Isotope
used is Indium III or 99Tc and is ingested as a capsule that
dissolves in terminal ileum. Gamma images are obtained at
specific time intervals to give an objective transit data.
3. Wireless motility capsule (WMC) provides a noninvasive
method of measuring gastric, small bowel and colonic
transit times. In addition to transit time, it provides the pH
changes and intraluminal pressure changes as it courses
through the gut. It is very sensitive and specific modality but
Table 1 – Etiology of acquired constipation.
Etiology of acquired constipation
Lifestyle-related causes Infectious etiology Anatomic
abnormalities
Functional
abnormalities
Physiologic and other
abnormalities
Diet
Pace of life
Medications
Weight loss/anorexia/
laxative abuse
Trypanosomiasis Neoplasms
Strictures
Adhesions
Volvulus
Rectal prolapse – Full
thickness, Internal
Rectocele
Nonrelaxaing puborectalis
Slow transit colonic
constipation
Megacolon/megarectum
Descending perineum
Diabetes mellitus
Hypothyroidism
Hypopituitarism
Porphyria
CNS trauma
Parkinson's disease
Brain and CNS tumors
Table 2 – Medicines that can cause constipation.
Amiodarone Carboplatin
Antacids (e.g. aluminum) Cholestyramine
Anticholinergics Erythropoietin
Anticonvulsants Filgrastin
{granulocyte
colony-stimulating
factor (G-CSR)}
Antidepressants Iron
Calcium channel blockers Lovastin
Diuretics Mesalamine
Ganglionic blockers Narcotics/opiates
Antiparkinsonians Pravachol
Bismuth Sandostatin
Bromocriptine Valproic acid
Bulk laxatives with
inadequate hydration
Vincristine
Table 3 – Types of dys-synergic defecation.
Type IRP IAP RAG
I Rise (+IRP) Rise (+IAP) 0
II No Rise (=IRP) Rise (+IAP) Àve
III Rise (+IRP) No Fall or <20% fall 0 or Àve
IV No Rise (=IRP) Fall 0 or Àve
Normal Rise (+IRP) Fall (ÀIRP) +ve
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x2
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4. is not available commercially as yet. A typical tracing
obtained from WMC is shown in Fig. 2.
3.3. Evaluation for ODS
Obstructed defecation syndrome as a possibility is a consid-
eration after exclusion, i.e. only after excluding all the above
reasons should a possibility of ODS be clinically entertained.
There are well-defined Rome II criteria for clinical inclusion of
ODS. They define ODS as constipation of at least 12 weeks
duration consecutively or nonconsecutively in the preceding
12 months with two or more of following features.
Straining at defecation for more than 25% of defecations.
Passage of hard stools for more than 25% of defecations.
Sense of incomplete evacuation for more than 25% of
defecations.
Sense of outlet obstruction for more than 25% of defecations.
Need for mechanical maneuvers like vaginal splinting
defecation, digital evacuation, or use of implements for
more than 25% of defecations.
Less than 3 defecations per week.
Once the constipation fits into the Rome II criteria for ODS,
an objective scoring for ODS is done using ODS scales. Various
ODS scoring systems have been defined. A patient friendly and
easy to compile ODS score, i.e., constipation and bowel activity
score or CABAS score, is used as shown in Table 4. The CABAS
score has been developed by us with the Indian perspective.
Even after all of above being complied with, it is prudent for
the surgeon to revise a check list for suspected ODS candidates
as follows:
The constipation has been refractory to medical manage-
ment for more than 3 months.
Fig. 1 – Abnormal colonic transit study with large amount of
stool and retention of more than five radio-opaque markers
mostly in the right colon in a subject with constipation.
Fig. 2 – Assessment of colonic transit with a wireless
motility capsule.
Table 4 – ODS-Agarwal CABAS Score.1
Symptoms Frequency
Never Rarely Sometimes Usually Always
Excessive straining 0 1 2 3 4
Incomplete evacuation 0 1 2 3 4
Use of laxatives 0 1 2 3 4
Digital pressure 0 1 2 3 4
Constipation 0 1 2 3 4
Never, 0; rarely, 1/month; sometimes, 1/week, ≥1/month, 1/day, ≥1/week; always, ≥1/day.
A collective score of 5 is suspicious, 10 indicative 15 diagnostic of ODS.
Fig. 3 – Evaluation for surgical constipation: 1: Uterus, 2:
Vagina, 3: Anterior rectocele, 4: Rectum.
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x 3
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5. Complete gastrointestinal work-up is normal including
colonoscopy.
Digital rectal examination (DRE) has been done (Fig. 3) to
exclude perianal pathologies: gross and dys-synergia or
spasm and intraluminal pathologies. Pelvic examination
with DRE should look for any excessive perineal descent,
rectocele, gross internal prolapse/intussusceptions, muco-
sal prolapse, exteriorization of dentate line, genitourinary
prolapse, and any enterocele on bidigital examination. In
addition to conventional DRE, a DRE in squatting position
with the clinician standing on the backside of the patient can
give a fairly good indication of internal prolapsed and
intussusception.
Some of the important observations on DRE are shown in
Table 5.
3.4. Imaging for pelvic floor dysfunction with ODS2
Imaging modalities like ultrasound, X-rays, and MRI have been
applied for assessment of pelvic floor dynamics. Dynamic
fluoroscopic defecography began in 1964. High-resolution
ultrasound and cine loop MRI have revolutionized our
understanding and management of pelvic floor dysfunction.
3.4.1. Dynamic fluoroscopic defecography
It requires rectal opacification with or without small bowel and
vaginal opacification if applicable (to rule out enterocele). In
case of bladder dysfunction, simultaneous cystography can
also be performed.
3.4.2. Anal endosonography
It is a good modality for evaluation of anal sphincters specially
to study the integrity of anal sphincters.
3.4.3. Dynamic MRI defecography
Itprovides all theinformation that a conventionaldefecography
provides. Better assessment of the defecation is possible with a
dynamic cine loop MRI. All the three compartments of pelvic
floor are seen in real time. It is emerging as the gold standard of
pelvic floor imaging. Table 6 gives a compact utility of various
imaging modalities for pelvic floor dysfunction.
3.5. Management of ODS
Lifestyle modification, dietary advice, and management of
co-morbid illnesses are a very important part of any clinical
Table 5 – Digital rectal examination.
Exam component Technique – Findings and grading
of response(s)
Inspection Inspect perineum under good light
Excoriation, skin tags, anal fissure,
scars, or hemorrhoids
Perineal sensation
and Anocutaneous
reflex
Normal: Brisk contraction of the
perianal skin, the anoderm, and the
external anal sphincter
Impaired: No response with the soft
cotton bud, but anal contractive
response seen with the opposite
(wooden) end
Absent: No response with either end
Digital palpation Tenderness, mass, stricture, or stool
consistency
Resting tone Normal, weak (decreased), or
increased
Squeeze maneuver Ask the patient to squeeze and hold
up to 30 s
Normal, weak (decreased), or
increased
Pushing and bearing
down maneuver
(1) Push effort: Normal, weak
(decreased), excessive
(2) Anal relaxation: Normal,
impaired, paradoxical contraction
(3) Perineal descent: Normal,
excessive, absent
Table 6 – Summary of the main imaging tests with their indications and expected findings.
Investigation Indications Expected findings
Defecography Difficult defecation/Dyschezia
unresponsive to initial treatment
Fecal incontinence (pre-op work-up)
Rectal prolapse
Rectocele
Unexplained pelvic pain especially
when enterocele is suspected
Internal rectal prolapse
Rectocele, enterocele, sigmoidocele
Pelvic floor descent
Paradoxal puborectalis contraction
Incomplete and prolonged contrast evacuation
Poor rectal stripping
Anal endosonography Fecal incontinence
After sphincteroplasty, if anal
incontinence persists
External and/or internal anal sphincter defect
Abnormality of external and/or internal anal sphincter
thickness
Postoperative status
MR defecography See defecography above
+
Evaluate global pelvic floor dysfunction
See defecography above
+
Entrocele
Genito-urinary prolapse
Abnormalities of the levatorani muscle
Static MR Fecal incontinence
After sphincteroplasty if anal
incontinence persists
See anal endosonography above
+
Precise evaluation of external anal sphincter atrophy
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x4
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6. approach to pelvic floor dysfunction, including ODS.3,4
Given the evolution in our understanding, imaginative
approaches that include traditional wisdom, dietary spice
management, biofeedback, and yoga have been shown to be
helpful in improving the quality of life in pelvic floor
dysfunction. These additional modalities have been found
to be helpful in improving the postoperative quality of life of
patients also.
3.6. Surgery for ODS – Stapled Trans-Anal Resection
Rectopexy (STARR)
Internal rectal mucosal prolapse with or without rectal
intussusception and rectocele has been found to be the factor
responsible for ODS. Resection of this prolapsing segment
without any luminal compromise by a trans-anal route was
reported by Dr. Longo for the first time. He described the
procedure of STARR using two layers of purse-string sutures as
per the experience gained from stapled hemorrhoidopexy. We
described the STARR procedure using six parachute string-like
suture placements in place of two rows of purse-string sutures.
This has made the STARR procedure easier to perform with
predictable donut harvest.
3.7. Operative procedure5
Once under anesthesia, chemoprophylaxis (a 2nd genera-
tion cephalosporin + imidazole or CO-amoxyclav alone) is
administered and patient is shifted to a lithotomy position,
to be adequately prepared and draped. I use a circular
cutting and stapling device (either PPH01, manufactured by
Ethicon Endosurgery or EEA Stapler 4.8 mm manufactured
by Covidien) for the rectal resection. It is similar to the one
used for stapled hemorrhoidopexy, i.e., PPH03 except for the
ability of PPH01 stapler to take in thicker tissues. This is
necessary because STARR involves full-thickness rectal
resection while the hemorrhoidopexy involves only mucosal
resection.
A circular anal dilator (CAD) is introduced into the anal
canal and secured in place with skin sutures passed through
the four slots in CAD. The orientation of CAD is such that the
slots are positioned at12 O'clock position, 3 O'clock position, 6
O'clock position and 9 O'clock position.
After securing the CAD, the internal rectal prolapse,
intussusceptions, is checked for by pushing in a ‘‘sponge on
holder’’ and pulling it out gently. This helps in identifying
the prolapse and the groove at the base of the recto-rectal
intussusception. The prolapse is now to be resected in two
sequential parts in hemicircumferential manner. It begins
first with the anterior hemicircumference. To pull the
anterior half of prolapse into the resecting/stapling unit of
PPH0-1, the traction is given by three parachute sutures. The
sutures are placed at the base of intussusception and are of
full thickness. First one to be placed is at 12 O'clock position,
and then 10 and 2 O'clock position parachute sutures are
placed. To protect the posterior hemicircumferential rectal
mucosa from being bitten by PPH01, a spatula is introduced
on the rectal mucosal through the 6 O'clock slotting the
CAD. This protects the posterior half from any entanglement
in the jaws of PPH01. The free threads of 10 O'clock suture
and one arm of the free thread of 12 O'clock suture are
jointly pulled through the left thread slot of PPH01. The
remaining arm of the free thread of 12 O'clock suture and
the two arms of the free thread of 2 O'clock suture are pulled
through the right slot in PPH01. Adequate traction is applied
on the threads to pull in the prolapse before the instrument
is tightened, fired, and removed as in a standard stapled
hemorrhoidopexy. The same steps are repeated in a mirror-
like fashion to complete the posterior hemicircumferential
resection with the fresh PPH01 instrument. The staple line is
examined for its integrity and hemostasis. This can be
reinforced by box-mattress sutures (as designed by me –
mattress suture placed across the staple line, and being
parallel to the staple line with the two buried strips of
mattress suture being equidistant from the staple line)
placed at 12, 3, 6, and 9 O'clock positions, using either
chromic catgut or synthetic absorbable sutures. The sutures
at 9 and 3 O'clock positions ensure the ‘‘dog-ear of tissue’’,
left at the junction of anterior and posterior resection, being
secured. This ensures the recto-rectal anastomosis being
smooth, secure, and dry. Postoperative management is
same as for standard stapled hemorrhoidopexy (view the
procedure at www.endosurgeon.org).
3.8. Pelvic organ prolapse surgery with STARR
(POPSTARR)
With the better understanding of pelvic floor dysfunction on
dynamic MR Defecography, the surgical approach has become
more precise. In case of multicompartmental pelvic floor
failure, STARR alone will address the posterior compartment,
leaving out the other two unaddressed.6,7
To address the
anterior and middle compartments, an extraperitoneal pros-
thetic suspension is done laparoscopically to sling the utero-
vaginal junction to the anterior abdominal wall. The laparo-
scopic extraperitoneal sling for the anterior and middle
compartments is supplemented by the STARR procedure for
the posterior compartment (view the procedure at www.
endosurgeon.org).
Conflicts of interest
The author has none to declare.
Acknowledgement
I am grateful to Nayan Agarwal, Ramneek Kaur, and Pooja Pant
for help in the manuscript preparation.
r e f e r e n c e s
1. Agarwal BB, Manish K, Pandey H, Doda R, Agarwal V,
Saxena KK. Stapled transanal rectal resection (STARR):
results of the first Asian experience. Ganga Ram J.
2011;1:118–121.
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x 5
APME-303; No. of Pages 6
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apme.2015.07.007

7. 2. Collet CS, Koning E, Dacher JN. Radiologic evaluation of pelvic
floor disorders. Gastroenterol Clin North Am. 2008;37:553–567.
3. Agarwal BB. Do dietary spices impair the patient-reported
outcomes for stapled hemorrhoidopexy? A randomized
controlled study. Surg Endosc. 2011;25:1535–1540.
4. Agarwal BB. Yoga and medical sciences. J Int Med Sci Acad.
2010;23(April–June):69–70.
5. Agarwal BB. STARR procedure for obstructed defecation
syndrome. How I do it? J Int Med Sci Acad. 2013;26:171.
6. Agarwal BB, Chintamani K, Mahajan KC. Pelvic floor
dysfunction: reinventing the spokes of the wheel. J Int Med Sci
Acad. 2012;25(January–March):13.
7. Agarwal BB, Chintamani K, Mahajan KC. Derriere distress –
defecation – deification. J Int Med Sci Acad. 2013;26:155.
a p o l l o m e d i c i n e x x x ( 2 0 1 5 ) x x x – x x x6
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