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Acta Cirúrgica Brasileira

Print version ISSN 0102-8650On-line version ISSN 1678-2674

Acta Cir. Bras. vol.13 n.2 São Paulo Apr./May/June 1998 



Luciano Ferreira Drager (BIC, CNPq)
Miriam Nogueira Barbosa Andrade (MD)
Sérgio Alexandre Conceição (MD)
José Renan Cunha-Melo (MD)



SUMMARY: Perianal fistula, usually has a criptoglandular etiology, developing from a perianal abscess and communicating the anal mucosa with the perianal skin. The aim of this paper is to study retrospectively 241 cases of perianal fistula (172 men and 69 women; 2,5:1) aging from 7 and 80 years old (average: 37,4 years), operated on at the Hospital da Clínicas - UFMG, from 1977 to 1996. The surgical techniques and post-operative outcome have been analysed. Perianal abscesses with spontaneous drainage were the predominant etiology (132 patients; 54,8%). Eighty percent were submitted to fistulectomy as the first surgical treatment. Among early complications (78; 32,4%), local pain was the most frequent (60; 24,9%). Among the late complications (136; 56,4%) fistula recurrence (101; 41,9%) was the most frequent. There were 141 reoperations in 80 patients. Fistulectomy was the predominant surgical technique employed for the treatment (101; 71,6%). The average hospitalization time was 6,3 days until 1990 and 1,5 day from 1991 to 1996, after the advent of day-surgery beds in HC-UFMG. The surgical treatment of perianal fístula has a significant rate of post-operative complications and a high recurrence rate, in spite of the short stay in hospital.
KEY WORDS: Perianal fistula; perianal abscess; fistula treatment; fistula complication.




The word fistula (in latin) means flute, pleat, groove, pipe or tube. In surgery, it implies an acute or chronic trajet of granulation tissue, connecting two epithelial surfaces that can be cutaneous, mucous or both.

Perianal fistula usually have criptoglandular etiology, developing from a perianal abscess and communicating the anal mucosa with the perianal skin. Infection of anal glands occur in 90 percent of the cases1. It can also appear in the course of specific infections such as tuberculosis, actinomycosis, lymphogranuloma venereum, Crohn’s disease, ulcerative rectocolitis, trauma, foreign bodies, malignant tumors of rectum, prostate, bladder, uterus or anus, Hodgkin’s disease, leukemias and post-radiotherapy2,3.

Men predominate in most series with a male: female ratio varying from 2:1 to 7:1. Age distribuition have an incidence peak between the third and fifth decades4.

A number of classifications for perianal fistula have been proposed. Some of them are briefly described below:

(1) Complete, blind external and blind internal. This classification postulated a rule relating the internal to the external hole. If the external hole is anterior to a imaginary line passing in the mid-point of the anus, the fistula follows a direct course to anal duct. If the external hole is posterior to that line, the course usually is sinuous. One exception to this rule is an anterior external opening situated at more than 3 cm from the anal margin, situation in which the course can curve and finish in the posterior medium line2.

(2) Subcutaneous and submucosa, low anal, high anal, ano-rectal5. In this classification perianal fistulas are grouped according to the relationship of the main tract to the anal musculature.

(3) Intersphincteric, transphincteric, suprasphincteric and extrasphincteric1. This classification define fistulas according to the course they take, with special reference to the anorectal ring.

(4) Simple and complex. The simple fistula constitute 90-95% of total, characterized by a fistulous tract easy to identify. The complex fistula have more than one fistulous course, subcutaneous or not. The treatment is more difficult and the post-operative complications are more frequent6. The treatment of chronic perianal fistulas is usually surgical and complications resulting from treatment even not being frequent, can be serious. Fecal incontinence by lesion of external anal sphincter is an example of complication that may occur.

The aim of this paper was to study retrospectively 241 cases of perianal fistula operated at the Gastroenterology, Nutrition, General Surgery and Digestive Surgery Service (GEN-CAD Service), Hospital das Clínicas - UFMG, from 1977 to 1996. The age and sex distribuition, the etiology, the surgical techniques and the postoperative outcome were analysed.



This is a retrospective study comprising 241 one patients (172 men and 69 women - 2,5:1) aging 7-80 years (average 37,4 years) that underwent surgery for perianal fistula in the period from 1977 to 1996. The age-distribuition of patients is depicted in figure 1.


Image46.gif (4001 bytes)

Fig. 1 - Age-distribuition of 241 patients with perianal fistula.


The data were obtained according to a previously established protocol containing informations about time of evolution, etiology, use of antibiotics, associated proctological diseases, previous surgery, type of surgery and postoperative complications.

The patient data were reviewed from records stored at the Medical and Statistical Record Service, HC-UFMG. One hundred and ninety patients were operated by the first time by members of the GEN-CAD Service (78,8%). The first operation was performed in other hospitals in 51 patients (21,2%).



Etiology: Perianal abscess with spontaneous drainage was the most common etiology, ocurring in 132 patients (55%). Other etiologies of perianal fistula are shown in figure 2.


Image47.gif (5200 bytes)

Fig. 2 - Etiology of 241 perianal fistulas treated by surgery at the Hospital das Clínicas - UFMG, Belo Horizonte, MG.


Evolution time: The time between fistula appearance and diagnosis varied from 10 days to 15 years. This information was not possible in 46 patients (19,1%).

Fistula type: Simple fistula ocurred in 137 patients (56,9%) and complex in 22 patients (9,1%). The type of fistula was not accounted in 82 cases (34%). Figure 3 contains informations about the type of perianal fistula and percentage of recurrence.


Image48.gif (4715 bytes)

Fig 3: Distribuition of perianal fistula according to type and recurrence rate.


Associated proctological diseases: Hemorrhoids (21; 8,7%) and skin tags (20; 8,3%) were the most frequent associated proctological conditions (fig 4).


Image49.gif (5344 bytes)

Fig. 4 - Associated-proctological diseases in patients with perianal fistula


Surgery: One hundred and ninety-four patients (80%) were submitted to fistulectomy alone as the first surgical treatment. In the remaining 20%, operations for associated proctological conditions (hemorrhoids, abscess, fissure, condiloma, polyps, etc) or fistulotomy were also performed.

Three hundred and eighty-two surgical procedures were performed in 241 patients, giving a rate of 1,58 operations/patient (fig 5).


Image50.gif (3630 bytes)

Fig 5: Number of surgical procedures, rate of reoperations and recurrences in 241 patients with perianal fistula.


Obs: As 51 patients were operated on in other hospitals before they were included in the group of 221 reoperations.

Complications: Among the early complications (78; 32,4%) local pain (60; 24,9%) was the most frequent. Late complications ocurred in 136 patients (56,4%). Recurrence (101; 41,9%) predominated among the late complications. Only about 11,2% of the patients with perianal fistula did not present early or late complications. Taking-out pain as complication, considering it occurs in the post-operative of almost all kinds of surgeries, the rate of early complications drop to 7,5 % and to 51% for late.

Reoperations: Fistulectomy was the predominant surgical technique employed in recurrence (101; 71,6%). Other techniques such as, curettage of fistula tract (30; 21,3%), colostomy (7; 5%), laparotomy (1; 0,7%), teratoma resection (1; 0,7%), nodule resection (1; 0,7%) also occured. In 21 cases (14,9%), an elastic bandage around the external anal sphincter muscles was associated with fistulectomy.

Previous Surgery: Fifty one patients (21,2%) had history of surgery for perianal fistula in other hospitals and presented to our hospital with recurrent disease. These patients have been allocated in recurrence group and were reoperated as described above.

Antibiotics: Twenty seven patients (11,2%), used antibiotics. In eight of them the fistula were simple (3,3%), and in five they were complex (2,1%). Fourteen patients (5,8%) that had used antibiotics had no report about the type of fistula.

Hospitalization Time: The average hospitalization time was 3,9 days. Separating the time of study in two periods it was observed a decrease in the hospitalization days when the first period (1977-1990) was compared to the second one (1991-1996). In the first period, the average time of hospitalization was 6,3 days whereas in the second period that number dropped to 1,5 days, coincident with the implantations of day-surgery beds at the HC-UFMG.

Mortality: No death resulting from perianal fistula itself or from the treatment was reported in the present series.



The majority of perianal fistulas, undoubtedly, are caused by infection, following perianal abscesses with intermitent drainage. However, it is important to exclude perianal fistulas associated with Crohn’s disease and ulcerative rectocolitis, avoiding extensive surgeries, because the wound healing is impaired and a prohibitive recurrence rate is observed in these inflammatory bowel diseases7.

The unpleasant symptoms and signs of perianal fistula usually make the patient visit the doctor. Unfortunately, there are many cases where the diagnosis is delayed, by patient’s ignorance, prejudice or fear. In about 12 % of the patients with perianal fistula in our sample, the evolution time was more than five years.

Associated proctological diseases are frequently seen with perianal fistula2. In our sample, hemorrhoids and skin tags were the most frequent conditions, but no studies to establish causal relationship was done.

The best surgical treatment is the complete excision of fistulous tract. This technique called fistulectomy, was used in almost all of the cases.

In spite of being a common disease, occuring in young patients and being easy to treat by surgery, the recurrence rate is high in perianal fistulas. Data from the literature reveal a recurrence rate varying from 0 to 33 percent8. When only Crohn’s perianal fistulas are considered, the recurrence was 48% at one year and 59% at two years9. Simple fistula was the most common fistula type, ocurring in 56,9% of the patients. This fact is in accordance with the literature. Nevertless, even in these cases, the recurrence was high (33,6%). The explanation for the high recurrence rate for these simple cases could be the fact that many young surgeons in their training program operate on at the GEN-CAD Service. Some fistula are difficult to treat, requiring more than one surgical intervention, what explains, at least in part, the high level of recurrence. If one considers the low mortality rate of this condition it may well be possible to explain why the treatment in many hospitals in Brazil is made by young surgeons with little experience, contributing to the increase of the recurrence rate. In this way the experience of the surgical team may play an important role for the success of treatment, decreasing the rate of recurrence. The identification of the complete fistulous course is mandatory to avoid its partial removal and the persistence of granulation tissue, which will maintain the fistulous process. Some of the recurrences are due to incomplete resection of the fistula10.

Anal incontinence, is a serious postoperative complication, resulting in psycho-social problems for the patients. It can appear due to muscle section during the surgical act, but may also be secondary to sphincter destruction caused by an abscess. In the presence of a transphincteric fistula it is possible to prevent an accidental lesion of the muscles using a rubber band around the sphincter. This artefact slowly cut the muscle, allowing the healing processes to gradually regenerate the muscle and avoiding the muscle function impairment. This technique was done in 21 patients (14,9%) with good results.

Fifty one patients had been previously operated on in other hospitals, to have their fistulas treated. These patients were allocated in the recurrence group of patients, but no information on how and how many times they had been operated on was available.

The use of antibiotics in the postoperative period was not a routine in our service. Only few selected cases received microbicides, showing that the infection in most of the cases is not an important finding in this clinical condition.

The decrease in hospitalization time observed since 1991 can be explained by the adoption of day-surgery beds in HC-UFMG to patients with orificial diseases. The patients are admitted in the morning, operated on in the afternoon of the same day and discharged in the morning of the following day. Because of this policy, the hospital stay of patients with perianal fistula was significantly reduced when compared to the previous period from 1977 to 1990, when the patient stay in hospital was longer.



Perianal fistula is a common disease occuring more in young males than in females. The surgical treatment of perianal fistula is followed by a high recurrence rate (41,9%). In spite of this high recurrence rate the patients can be discharged, after no more than 36 hours from hospital admission. No mortality occured in the present series caused by the disease itself or by its surgical treatment.



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2- Goodsall, D.H. & Miles, W.E. - Ano-Rectal Fistula. Diseases of the Anus and Rectum. Longmans, Green & Co, 92-137, 1900.        [ Links ]

3- ROSS, S.T. - Fistula-in-ano. Surgical Clinics of North America, 68: 1417-26, 1988.         [ Links ]

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5- Gabriel, W.B. - Fistula-in-ano. In: GABRIEL, W.B. - The Principles and Practice of Rectal Surgery. London, HK Lewis & Co, 1945. p. 160-97.        [ Links ]

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8- Garcia-Aguilar, J.; Belmonte, C.; Wong, W.D.; Goldberg, S.M.; Madoff, R.D. - Anal fistula surgery: Factors Associated with Recurrence and Incontinence. Diseases of the Colon & Rectum, 39:723-9, 1996.         [ Links ]

9- MAKOWIEC, F.; JEHLE, E.C.; STARLINGER, M. - Clinical course of perianal fistulas in Crohn’s disease. Gut, 37: 696-701, 1995.        [ Links ]

10- SANGWAN, Y.P.; ROSEN, L.; REITHER, R.D.; STASIK, J.J.; SHEETS, J. A.; KHUBCHANDANI, I.T. - Is simple fistula-in-ano simple? Diseases of the Colon & Rectum, 37: 885-9, 1994.         [ Links ]




Department of Surgery, Faculty of Medicine and GEN-CAD Service, HC, Federal University of Minas Gerais, Belo Horizonte - MG, Brazil.

Address for reprints:
Professor José Renan Cunha-Melo
Departmento de Cirurgia FM - UFMG
Av. Alfredo Balena 190, Santa Efigênia CEP 30130-100
Belo Horizonte, MG, Brasil
Tel/Fax: (031) 2736530
Financial Support: CNPq, FAPEMIG.

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