The Complete Anorectal Examination - An Art Forgotten
As an intern, I was always considered a “passenger” in patient management. After I joined residency, as decent as I was with clinical acumen, on my first day in clinics I was given a thick bunch of papers and was told that all these patients needed an anorectal examination. Fumbling my way around it, it took me almost 2 full hours to go through that group of 20+ patients, often having to go back to certain patients on account of having missed an important part of their evaluation.
Not everybody needs to go through this, so let’s simplify the steps involved in a complete anorectal examination.
(Just to note that many parts of this article will feel repetitive – it has been done deliberately to ensure that all relevant information are reinforced to the point of boredom!)
The first step, and the most important of them all is finishing a complete history of why the patient has chosen to get a surgical consult at this moment in time. Address all concerns while talking, as establishing a level of trust ensures a smooth examination. The environment needs to feel safe, and patient’s privacy is of highest priority.
Most patients are apprehensive, and this can make them decide to not get examined (which is an absolute contraindication), or cause sphincter/gluteal spasm while examining, which can lead to a sub-optimal examination. All of this is avoided by making sure that the talking part addresses all possible concerns, explanation of the procedure at hand, the why’s and what’s of it, explaining the risks of the patient choosing to refuse the anorectal examination also.
Another rule of thumb is offering a chaperone. It bodes well to make it a habit; choosing to have a chaperone or not will be the patient’s decision.
Once we get to the actual examination, keeping the patient clothed/ covered till the exact moment that we need to examine , and of course, ensuring privacy at all times, documenting every step – the explanation, the consent - seem like trivial things, but significant practices that need to become a subconscious reflex.
One last thing that needs to be mentioned is active communication. You may have done a great job at explaining “what” was going to happen, but patients seldom know “when” it was going to happen – so a sort of a running commentary while performing the examination ensures that the patient doesn’t feel uncomfortable, knows what to expect, and when to expect it.
The Anorectal examination:
There are three (3) components to performing a comprehensive anorectal examination –
1. Patient positioning
2. Visual inspection, and palpation of the anorectal region
3. Digital examination, and endoscopy
Patient positioning:
There are 2 positions that can be utilised for performing an anorectal examination –
a) Prone jack-knife position
b) Left lateral position
The prone jack-knife position:
Also known as the knee-chest position, the prone jack-knife position is widely regarded as the most optimal for a thorough anorectal examination with excellent visualisation of the perianal, gluteal and sacrococcygeal areas. It also provides excellent access for endoscopy (anoscopy in the clinic, or formal sigmoidoscopy).
The only limitation is the requirement of a specialised proctoscopic table, and a few relative contraindications (recent abdominal surgery, late pregnancy, debilitated patients etc,.)
The left lateral position:
Also known as the Sims’ position, it is the most commonly used position on a routine examination couch. The patient lies on their left side with hips and knees flexed to make a 90 degree angle with the trunk. The buttocks need to project a little outside the examination table and may be supported by a towel roll/small pillow to facilitate ergonomic visualisation and access to the anorectal region.
The disadvantage of this position is that during inspection, visualisation of the anterior perineum is possible only on retraction of the buttock
Fig 2: Sims’ position used during endoscopy
2. Inspection and palpation of the anorectal region:
Proper lighting is crucial for a comprehensive examination. The patient (already in position) is explained again about what is about to happen, and examination gloves are worn.
Inspection of the anorectal region consists of a step-wise evaluation of the buttock, the sacrococcygeal area; the perineum & perinatal area is visualised by spreading of the buttock.
Things to look for include the general appearance and symmetry of the area, fecal soiling, discharge, scarring, ulcers, fissures, fistulae, masses, excoriation, sphincter complex and the perineal body bulk, pelvic organ prolapse, and overt evidence of inflammatory bowel disease.
The patient is then asked to strain/ perform a Valsalva manoeuvre to assess for perineal descent or prolapse (best position to demonstrate this is squatting on a commode after rectal enema).
This is followed by gentle palpating of the anal verge, which demonstrates the anocutaneous reflex (a.k.a the Anal ‘wink’) which is indicative of an intact pudendal nerve.
3. Digital rectal examination & endoscopy:
It’s likely you’ve heard some surgeons going -
“The only reason a digital rectal examination is NOT done is when the patient lacks an anus or the surgeon lacks a finger”
As “cool” as it sounds, it’s a gross oversimplification of the reason to perform a rectal examination. Obviously not indicated in patients who do not have any abdominal or pelvic/perineal complaints, digital rectal examination (DRE) should not be attempted in painful conditions (fissure-in-ano, thrombosed hemorrhoids) and in neutropenia patients (for fear of setting off the cascade of sepsis)
When performing a DRE, adequate lubrication, patience, gentleness and a high level of attention to detail are mandatory for a complete anorectal examination. It is wise to reiterate the importance of a systematic approach to not miss anything; having to reexamine the patient is embarrassing for obvious reasons.
Explain once again to the patient as to what is going to happen, and crucially to let us know if there’s any discomfort at any time during the examination process. A well lubricated index finger is placed across the anus to lubricate the area and then the finger is introduced.
The distal rectum and the anal canal should be examined circumferentially to look for the feel of the mucosa, and to feel for polyps, strictures, masses, and in relevant cases, the induration of the internal opening of a fistula-in-ano. In addition to the luminal characteristics, extra luminal features- the pelvic examination, feel of the prostate (modularity, enlargement, cragginess)in males, feel of the cervix, vagina, and the rectovaginal septum in females (may need a bimanual examination - remember to not cross-contaminate) are all things that need to be patiently sought out for.
If there’s spasm of the sphincter complex for any reason despite gentle introduction, the examining finger is withdrawn and the procedure is reattempted while the patient is bearing down (as it relaxes the sphincter complex).
During the DRE, a Valsalva manoeuvre will allow for lesions in the upper rectum to be accessible to the examining finger. Resting and squeeze tone of the sphincter is assessed by asking the patient to voluntarily contract their sphincter.
An important event that needs to be noticed while the patient is contracting their sphincters is to note the examining finger getting pulled up deeper into the anal canal; on pulling the muscles posteriorly, the anal opening should gape and return to normal tone, which represents an intact reflex pathway to the thoraco-lumbar spine.
Once this is done, the examining finger is seen for the colour & consistency of the stool, and for presence of blood only the tip of the examining finger.
The Anoscope
The anorectal examination is incomplete without some form of endoscopic evaluation. The scopes commonly used in the clinic is an Anoscope. Rigid sigmoido- / procto-sigmoidoscopy can also be done as an outpatient procedure with or without light sedation. Such office procedures do not require any form of bowel preparation.
The anoscope consists of a bevelled scope, an obturator with an optional light source. The lubricated anoscope is inserted into the patient’s anal canal after full explanation, along the anterior-posterior axis of the anal canal. Whenever the anoscope needs to be negotiated, the obturator has to be reinserted and the required manipulations need to be done.
Fig 3: Different types of Hirschmann anoscopes with obturator. The last one is a paediatric scope
Courtesy - The ASCRS textbook of Colon and Rectal Surgery, 3rd Ed
The anoscope provides excellent visualisation of the distal rectal mucosa, the anal transition zone, the dentate line, the anal columns of Morgagni, and pathologies like hemorrhoids, polyps, growths/ strictures and the internal opening of a fistula-in-ano.
The scope also provides excellent access for biopsy of suspicious lesions, and for therapeutic interventions like polypectomy or sclerosant injection into a hemorrhoid. However, it needs to be remembered that any intervention below the dentate line needs anesthesia as the area is pain sensitive, but interventions above the dentate can be done with barely any pain, although a light sedative is much appreciated by the patient.
We are still not done! While removing the scope, the patient is asked to bear down once more to visualise any prolapsing anorectal mucosa, a polyp, or prolapsing hemorrhoids.
Once the scope is out, thank the patient, and leave them to dress themselves while we ensure that all findings are documented!
Author: Anirudh Murali
Sources and citations
Chapter 4: Endoscopy, The ASCRS textbook of Colon and Rectal Surgery, 3rd Edition, pp. 45-48