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Disease of the anal canal


Where is the anal canal located?

The human digestive system, measuring 7 m including small and large bowels, ends in the rectum, which is however only 15 cm long. The last third of the rectum is called anal canal, only measuring 3 - 6 cm. In this section of the anus, the transition from the intestinal mucous membrane to the outward skin is found.

What function does the anal canal have?

The main function of the rectum consists of the storage of stool, which requires, on the one hand, a good elasticity of the tissue in this region and, on the other hand, a good occluding mechanism. The rectum itself has the form of an S, so that the pressure exerted by the accumulated stool (when the bowel is filled) is not only passed on to the anus, but also on the pelvic floor. Only for the purpose of dejection it stretches for a short while, releasing the stool in this way.
The closure of gas and stool, an important function of the anal canal and of the anus, is accomplished through

1. a multi-layered external muscle tourniquet, structured in a complex manner, extending as far as the anus,

2. a cavernous body in the form of a cushion, composed of small veins and arteries, located on both sides of the mucous membrane in the anal canal, making a precise regulation possible,

3. a section at a short distance from the anus, in which lengthwise folds of mucous membrane form bag-like structures, functioning like a valve.

The evacuation of the bowels is activated by a complicated control circuit, which again is regulated by touch and distension stimuli from the rectum in such a way that the human being has stools only once per day. The frequency of stools, however, is very individual and subject to great variations.


Haemorrhoids as the most common disease of the anal canal

More than 50% of people over 50 years suffer from haemorrhoids. Thus, this disease is one of the most frequent complaints of man altogether, and in western civilization, it is regarded as endemic. The causes for it are to be found in our dietary habits, in pressing while having stools, in excess weight, and in a hereditary weakness of connective tissue. These factors cause an increased muscular tension around the anal canal and the anus. This initially results in a congestion of blood around the network of vessels of the cavernous body. Subsequently, the cavernous body enlarges and its tissue becomes nodal. If one imagines the transverse section of the anal canal as a circle, these nodes form especially at 3, 7, and 11 o'clock (the patient lying on his back). The classification of haemorrhoids according to the degree of severity is as follows:

Degree 1: The congestion of blood in the cushion-like network of vessels causes an enlargement and thickening of the cavernous body.

Degree 2: The soft, strongly enlarged section of tissue, formed like a stalk, prolapses into the anal canal, sometimes as far as the anus. The typical haemorrhoidal node has developed

Degree 3: The haemorrhoidal node is found constantly protruding from the anus.

How do I recognize haemorrhoidal complaints?

Any kind of constant irregularity of stool, pain around the anus, or bleedings should be taken seriously, and the patient should immediately consult a specialist because other diseases of the rectum can also make themselves felt in this way. The classification of haemorrhoids is made by defining various stages, which are closely linked with specific symptoms corresponding to the degree of severity:

Degree 1:As a rule, the patient notices light-red bloodspots on the toilet paper. The reason for this is that the evacuation injures the sensitive mucous membrane of the significantly enlarged network of vessels, causing a superficial bleeding. Blood from higher placed sections of the bowel flowing off through the anal canal is usually dark.

Degree 2:An unusual feeling of pressure at the anus during evacuation is caused by temporally prolapsing haemorrhoidal nodes, often accompanied by pains. Bleedings rarely occur.

Degree 3:The haemorrhoidal nodes permanently found outside the anus are parts of the regular mucous tissue of the anal canal prolapsing to the outside. If there is a permanent prolapse of haemorrhoids in several places, it is called prolapse of the anal mucosa. Accompanying symptoms are here the anal eczema, itching, and stool smear.

Necessary clarifications and diagnostic possibilities

The first thing the specialist has to do is to get to know the beginning and the course of the complaints in a detailed conversation with the patient. In this connection, the central questions are about irregular stools, bleedings, pains, and itching around the anus, but also questions about unusual loss of weight and fitness. To examine the anus and the rectum, there are two possibilities:

The patient lies on the examinational stretcher on his left side with his legs pulled up.

He lies on his back on an examination chair in a dorsosacral position, his legs angulated on supports

After the patient lies in the correct positioning, the skin of the anus is inspected: it is important for the examining doctor to find out whether there are any changes of the skin in this area or reddening, eczematic or inflammatory diseases. The patient is asked to exert pressure to provoke an anal prolapse, a prolapse of the rectum, or haemorrhoids. These diseases can be diagnosed by their typical manifestations. Then, the doctor will cautiously explore the rectum with his index finger to test the elasticity of the outer and inner constrictor muscle. Afterwards, the rectum is explored, but haemorrhoidal nodes do not become tactile this way. They are just blood-filled vessels, which empty at once when pressed and which disappear into the soft mucous membrane. The exploring finger will feel, however, if there are lacerations of the mucous membrane, strictures, or irregular outlines of the anus. At the end of the examination, the size of the prostate is explored through the mucous membrane with men. With women, the external neck of the uterus is assessed. The precise pressure of the anal muscular system can be measured with special, sensitive pressure sounds. This is important in the case of additional fissures or anal incontinence.

The haemorrhoidal nodes themselves, their classification, and their position in the anal canal at 3, 7, and 11 o'clock, can only be assessed more precisely with the help of a proctoscope. This is a bevelled, pipe-like instrument open at the front that measures 5 cm and is equipped with a small lamp. It is cautiously pushed into the rectum and normally does not cause any pain to the patient, except an unpleasant feeling of pressure. With this instrument, the inspection of the anal canal is good, and especially haemorrhoids and fistula can be well assessed. The rectoscope is a 20 cm long instrument with which the last 20 cm of the rectum can be inspected. To enable the doctor to completely inspect the inner part of the rectum, air has to be pumped in. If the examinations with these two instruments are inconspicuous and if there is the faintest indication of perianal bleedings (loss of blood via the rectum) from the patient's anamnesis, the doctor should suggest a colonoscopy to rule out a carcinoma in the upper sections of the bowel. The colonoscopy is carried out by gastro-intestinal specialists, who use a thin flexible instrument of 2m in length, with which the whole large bowel can be inspected.

How can haemorrhoidal complaints be treated?

Independent of the gravity of the individual case, patients with haemorrhoidal complaints suffer from acute anal itching (anal eczema) and/or from pains while having stools. To alleviate the anal itching and the eczema, the patient will be prescribed anti-inflammatory ointments and suppositories. Besides, there are suppositories, which have a pain-killing effect or contain also vasoconstrictive substances that may alleviate the complaints in addition. In more serious cases, cortisone preparations have to be prescribed. Specific therapies are:

Haemorrhoids of degree 1-2:

- Sclerotherapy of the enlarged cushion of vessels by injecting a special liquid.
- Application of a tourniquet to tie off the haemorrhoids with a rubber ligature: the haemorrhoids are cut off from the blood
supply at their base with a tight rubber band and thus are sclerosed.
- Laser treatment: the inner haemorrhoids are sclerosed by direct contact with a special laser device

Haemorrhoids of degree 2-3: at this stage of the disease an operation becomes necessary, which can often be carried out with spinal anaesthesia.

- Excision of the haemorrhoidal node according to "Milligan-Morgan" or "Ferguson".
- Excision according to "Longo" with a special staple suture device.

In the case of sclerotherapy, the widened vessels are exposed to an adhesion with a special liquid. As a result, cicatricial tissue grows and fixes the cushion of vessels, formerly enlarged, again to the mucous membrane below.

In the surgical therapy according to Milligan-Morgan, the base of the haemorrhoidal node in the anal canal is exposed and the central supplying vessel of the node is dissected and tied up. Then, the haemorrhoidal node is shelled out. As the protrusion of the node has considerably expanded the skin around the anus, a small triangular segment of the skin is cut out, and the resulting new edges are sutured under careful treatment of the underlying musculature.

In the treatment according to Longo, a special linear stapling device is used to grip the mucous tissue about 2 - 3 cm inside the anal canal in a round suture and tie it together. The device puts a circular suture, at the same time removing about 1 cm of the mucous tissue. The mucous tissue is removed together with the corresponding part of the vessel lying below and is immediately closed with clamps. All vessels leading to the haemorrhoids are closed with this suture. The so-called intermediate vessels, located between the classical sections at 5, 7, and 9 o'clock, are also closed to prevent the danger of a relapse. After both operations, stripes with ointment are inserted into the anus.

As a rare complication after a treatment according to Milligan-Morgan, the anal stenosis should be mentioned if too much of the mucous tissue was removed. After both methods, there may be passing, involuntary stools because of postoperative swellings of the mucous tissue at the anus. This happens because the exact regulation of the constrictor may have been disturbed a little until a complete recovery has been reached. It is important that the surgeon only removes the mucous membrane without injuring the constrictor, which lies directly below the mucous membrane.

What happens after the operation?

After a surgical treatment, it is important to administer sufficient pain killers. At the same time, medicaments are given to soften the stools. After stools, sitting baths and the application of pain-killing suppositories are suggested. Some patients may have to use potent pain killers after the operation for some days. At the beginning, slight disturbances while having stools are quite normal and immediately disappear after the complete healing of the wounds. In addition, the patients are advised by a specialist for nutritional counselling, e.g. food enriched with wheat germs, so that a new occurrence of haemorrhoids can be avoided in the future.


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