This article provides a preliminary discussion on issues related to the surgical treatment of high anal fistula, such as the recognition of the internal orifice and rectal ring, the location and number of incisions, hanging and non-hanging operations and surgical cure and recurrence, combined with our own clinical experience, and provides some ideas and experiences for the surgical diagnosis and treatment of this disease. High anal fistula is one of the anorectal diseases that require surgical treatment, especially the complex ones, and there is a crucial relationship between the incision design and the healing of the disease during surgery. For this reason, a variety of surgical approaches have been developed, with two general categories: wire and non-wire surgery. The following author discusses the clinical understanding of the problems associated with the diagnosis and treatment of high anal fistula.
1. Classification of high anal fistula
In 1975, the National Anal Academic Conference established a unified classification standard for anal fistulae, which is marked by the deep line of the external sphincter. In terms of complexity, there is a distinction between simple and complex high-grade anal fistulas. The anatomical classification includes: fistula in the colorectal fossa, fistula in the pelvic rectal space, fistula in the posterior rectal space, and fistula in the submucosa of the rectum. It can develop in a single interstitial space on one side of the rectum or in both sides or in multiple interstitial spaces simultaneously.
If the relationship between the anal canal and the sphincter is considered, anal fistulas can be divided into four categories, namely intersphincteric, trans-sphincteric, suprasphincteric, and extrasphincteric fistulas. Intersphincteric fistulas are mostly low anal fistulas, while others are mostly high anal fistulas. Trans-sphincteric fistulas are a consequence of abscesses in the colorectal fossa, and a few fistulas cross upward into the pararectal connective tissue to form pelvic rectal fistulas. Supra-sphincter fistulas pass upward through the anal raphe and then downward to the colorectal fossa to penetrate the skin. Extra-sphincteric fistulas, the least common, are the result of pelvic rectal abscesses combined with abscesses in the colorectal fossa, where the fistula crosses the levator muscle and communicates directly with the rectum.
2.The basis for the selection of hanging wire surgery
Once a fistula is formed, there is very little chance of self-healing, and the complication of the fistula causes many problems for the patient. The complex anal fistula after many recurrent episodes not only brings difficulties in treatment, but also affects the normal physiological function of the anus, and can even be complicated by the formation of rectovaginal fistula, rectal urethral fistula and rectal bladder fistula, which endanger the surrounding organs and have the tendency to become malignant. Therefore, timely surgical treatment is very necessary, and for this reason, choosing a reasonable surgical approach and designing a reasonable surgical incision are issues worthy of deep consideration by clinicians. However, with the development of the times, some non-wired procedures have gradually emerged.
There are different views on how to determine the criteria of hanging and non-hanging. In the author’s opinion, if the blind end of a pelvic-rectal gap fistula is more than 6-7 cm from the anal verge or if there is a secondary ulcer on the rectal mucosa, the chances of surgical failure or fistula recurrence are very high when choosing non-hanging wire surgery. Some operators do not recognize this, and in many cases it is because the patient has changed the hospital and the treating surgeon. Simple high-grade fistulas that are not fistulas in the pelvic-rectal space and that do not have secondary internal openings in the rectal mucosa can be treated selectively with untethered surgery. For complex high anal fistulas, especially those with secondary internal orifices, it is better to choose wire surgery.
3.The location and number of incisions
In the case of simple high anal fistula without wire surgery, the anal canal and paranal skin can be excised by radially cutting outward from the primary internal opening in the dentate line area. The distance between the incisions should not be too far and the skin bridge between the incisions should not be too thick, and a tension-free auxiliary drainage rubber strip or silk thread should be tied and removed in 7-14 days. The anal canal rectal ring is a group of muscles around the anal canal rectum below the pelvic septum above the dentate line, consisting of the puborectalis muscle, the deep external sphincter, the internal sphincter and the joint longitudinal muscle fiber.
This ring has an important sphincter function and can be completely cut off during surgery, resulting in anal incontinence. In high anal fistulae, the anorectal ring can be fibrosclerotic due to inflammatory stimulation, so a sclerotic anorectal ring can be used as a diagnostic basis for high anal fistulae. When the anorectal ring is fibrotic, the elasticity of the ring decreases, the ring adheres to the surrounding tissues, and the mobility decreases. Theoretically, it is possible to make a one-time incision during surgery, but in practice, few incisions are made because of the fear of anal incontinence after a one-time incision.
For high anal fistulas, the rectal ring on the dentate line can be considered as a fistula sidewall in the area between the dentate line and the blind end of the fistula, and the hanging wire shaves this wall to open the cavity for complete drainage. If the location of the fistula is not too high, the wall of the tube in the rectum is less likely to achieve closure; when the distance is long, it is difficult to achieve adequate drainage without hanging a wire for surgery, and its knot is thick and the fibers sclerotic, according to the author’s experience can be cut or partially cut at once. The distance from the tooth line to the blind end of this section is short, fully dilated, post-operative drug changes in place, not to hang the line to operate the depth of the tube, determine the length and width of the incision, the incision is too short is not conducive to drainage, too wide is a long healing time or delayed healing, you can make a radial auxiliary counterpart drainage incision near the main incision according to the situation, so that the main incision is conducive to healing. The blind end of the fistula can also be fixed with a drainage tube after debridement and reopening for postoperative dressing changes and irrigation. In the case of a high complex fistula, the lumen can be incised at a low level and the lumen can be threaded at a high level above the dentate line. In other words, a probe is inserted from the lumen to the blind end of the fistula, and a rubber band is artificially inserted through the rectal wall to hang the wire. The fistula lumen is incised from below the primary internal opening
The lumen of the fistula is opened. The incision is usually made in the left posterior or right posterior position (5 or 7 o’clock in the lithotomy position). In the case of multiple interstitial fistulas, multiple incisions can be made to drain the fistula, i.e., a radial incision relative to the anus is made at the corresponding body surface.
4. Recognition of internal fistulae
Anal fistulas have primary internal ports, fistulas, branches and secondary external ports. The primary internal orifice of anal fistula is usually in the dentate line area, mostly in and around the anal sinus and on both sides of the posterior median line, but can also be in the lower rectum or any part of the anal canal. For complex fistulas, the branch canals can be identified by injecting 30%-40% iodine oil into the external orifice, and the distribution of the fistula can be seen, and in the case of secondary orifices, the contrast fluid can be seen to spill into the rectum. A retrospective analysis of a group of fistula cases by Cirocco (1992) was performed to test the accuracy of Goodsall’s rule in predicting the course of fistulas, and it was found to be quite accurate in predicting the course of fistulas with posterior external orifices.
The management of the internal orifice of the fistula is pivotal in the healing of the fistula. Removal of the internal orifice during untethered surgery is difficult if the incision is made outward from the dentate area. This stems from the anatomical understanding of the substance of the internal orifice, i.e., it is not a point but an area, and it is not easy to define how far to remove during surgery. In many cases, the operator believes that the orifice has been completely excised and healed during surgery, but clinically, a small gap can be found in the dentate area during anal examination, which calls into question the completeness of the orifice excision and is an important factor in fistula recurrence. In the case of a suturing procedure, the endograft is relatively completely destroyed by the strangulation of the endograft or the side of the edge of the endograft with a rubber band. Therefore, when not hanging wire surgery, the excision of the internal orifice should be expanded for good, and part of the relevant area can be excised upwards.
5.The recognition of anal canal rectal ring
Bureau is the surgery ends in non-healing or failure. For hanging wire surgery fistula healing, although to do the normal anal defecation, but anal overflow moist and other situations occur, which is also a major problem of clinicians confusion and trouble, can only be expected to reduce the damage damage to the tissue at the time of surgery to the lowest level or zero. Once the anal overflow moist and other conditions occur, timely symptomatic treatment should be given, and patients should be instructed to carry out anal function exercise and pay attention to anal care and health care in a timely manner.
6.Surgical cure and recurrence of failure
High-grade anal fistula surgery has a high chance of failure and recurrence, and no physician in the clinic dares to make a 100% commitment to the surgical cure of high-grade complex anal fistula. The difficulty of treating high anal fistulas is determined by individual patient differences, the choice of surgical approach, the clinical experience of the operator, and the many uncertainties during and after surgery. It cannot be assumed that a successful surgical operation will result in the cure of the fistula, because postoperative dressing changes are as important as surgical treatment.
The post-operative healing process requires careful, meticulous and persistent medical attention, as well as an eye for timing to correct treatment deviations and unfavorable healing. As for the patient’s mental factors, nutritional status and communication and cooperation between the doctor and patient are also important in the treatment. The Chinese medicine’s rule of eliminating decay and creating muscle, simmering pus and growing flesh for medicine and drugs can have a multiplying effect on the healing of postoperative wounds. Therefore, if the above work is done carefully and comprehensively in the treatment of high anal fistula, the chances of successful surgical treatment of high fistula can be greatly increased.