gms | German Medical Science

Anal fistulas are a common disease. Most of the patients are between 30 and 50 years old. More often men have fistulas compared to women.

Most anal fistulas can be easily treated by fistulotomy [1]. Proximal (high) anal fistulas shouldn't be treated with a fistulotomy because of the risk of fecal incontinence [2]. Therefore operative techniques have been developed that could reduce that risk by repairing the anal sphincter. Despite these techniques the rate of anal continence disturbance still reaches 30%. After advancement flap procedure healing of the fistula was achieved in 60–70% [3]. The relative risk for fecal incontinence is much higher for reoperations or persisting fistulas.

As an alternative technique the fistula plug was introduced in 2006. The plug technique occludes the fistula. Initial high healing rates could not be reproduced in subsequent publications. Realistic healing rates seem to be around 30% [4], [5], [6]. A main problem was the fixation of the plug. Actually a new absorbable plug that could be better fixated because of its design has been introduced. In this study we present the initial German results of this procedure.

In three surgical units and by five colorectal surgeons 40 consecutive patients (30 male, 10 female; age 51±12 (24–79) years) were operated by implanting the Gore BioA Fistula Plug^® (Table 1 [Tab. 1]). Retrospective data have been collected by means of a pooled analysis of the three surgical units. There was no prospective general protocol.

There were 28 high transsphincteric fistulas and 12 fistulas with suprasphincteric tracts. Four patients suffered from Crohn’s disease. Twenty patients had undergone only primary drainage of the abscess. In two additional patients a biological plug-insertion had taken place without success. Five patients had had a advancement flap procedure on their fistulas and 12 patients underwent several unsuccessful interventions (Table 2 [Tab. 2]). The number of previous surgical interventions was 3.4±2.8 (mean 2). It differs widely between the five surgeons (Surgeon no 1: 6.4, no 2: 4.1, no 3: 4.1, no 4: 1.9, no 5: 2.3).

A seton has been placed in 24 patients. Location of the fistula was between 5 and 7 o'clock lithotomy position at the dorsal anal aspect in 29 cases. Only three fistulas were located ventrally.

Continence was defined according to the Parks’s classification depending on clinical history. Preoperatively 33 patients were completely continent, seven patients complained of minor incontinence disorders (six with incontinence for gas (Grade 1) and one other with intermittend incontinence for liquid stool (Grade 2).

The length of the implanted plug arms was 2.5 to 9 cm (4.8±1.4 cm). The range between the five surgeons was 3.8 to 5.5 cm. In 18 patients arms had to be cut underneath the head to get the plug pulled through the fistula channel (1 arm: n=1, 2: n=5, 3: n=7, 4: n=4, 5: n=1). In 22 procedures no arms have been removed. There was a large difference between the surgeons: Whereas two surgeons had only a removal of 0.4 arms at mean, the other had removed 0.8, 1.8 resp. 3.8 arms. In none of the patients a special preparation of the head was done. A mucosal flap for covering the plug has been done in all patients except two.

A seton has been placed in 21 out of 36 patients without Crohn’s disease.

The postoperative treatment regime of the surgeons was done according to the rules of the different centers as shown in Table 1 ([Tab. 1]). The patients were advised to avoid heavy physical work for two weeks.

Healing of the fistula was defined as complete closure of the internal opening and the external wound and no symptoms of inflammation according to German guidelines [3].

Follow-up was done by clinical examination in the outpatient department.

Due to the heterogeneity of the study group (40 patients, 5 surgeons with sligthly different intra-, pre- and postoperative procedure) we don't give any statistical significance of our results.

All operations were performed in general or spinal anaesthesia in lithotomy position. The bowel has been cleaned with orthograde lavage. All patients received a single-shot antibioses with cephazoline and metronidazol. In all patients without a previous seton placement, probing of the fistula was easy and the internal opening of the fistula was identified in the anal canal. The bioabsorbable Gore BioA Fistula Plug^® consists of 67% of polyglycol acid and in 33% of trimethylen carbonat. Metabolization is accomplished by the citrat circle into carbondioxide and water. Optimally the resorption starts at the 6^th week and is completed after 6–7 month. The length of the six plug arms is 9 cm.

After identification of the fistula (Figure 1A, B [Fig. 1]), the tract is debrided with a curette or brush. The external opening is cored out by diathermy to accomplish sufficient drainage. Inside the anal canal a mucosa-submucosa-flap proximal of the internal opening was raised. If necessary single arms of the plug were cut directly beneath the head of the plug (Figure 1C [Fig. 1]) in cases where the fistula tract was too narrow for the whole plug with its 6 arms. After gentle dilatation of the internal opening, the plug was pulled through with the suture and/or a surgical clamp (Figure 1D [Fig. 1]). All arms of the plug were pulled tight and the head was fixated to the internal sphincter muscle using 2–3 sutures (PDS 2-0) (Figure 1C [Fig. 1]). Finally it was covered with a mucosa-submucosa-flap (Vicryl 2-0) (Figure 1E [Fig. 1]). Only in two patients this was not possible due to local anatomical reasons. Finally the arms were shortened so that they were a few mm longer than the external wound (Figure 1F [Fig. 1]). This procedure differs only a little between the five surgeons. The differences concerning the cutted arms and the length of the plug are mentioned above.

The median operation time was 30±6 minutes. Perioperatively there was no case of a bleeding or any urinary retention. Postoperative nutrition depends on the individual regime of the surgeons from no restriction at all to total parenteral nutrition (Table 1 [Tab. 1]). The median hospital stay was 4.9±1.9 days with no difference between the different surgical units. In two patients loss of the plug with persistence of the fistulas was seen in the first two postoperative weeks. Complications occurred in three patients: On day 9 after the operation one patient had to be reoperated due to a fluid retention of the perianal wound. One female patient was complaining of increasing pain with readmission to the hospital. Complaints could be handled with analgesics for a few days. The third patients suffered from pneumothorax after punctuation of the subclavian vein for central venous catheter.

Four weeks after the operation all patients had no signs of inflammation with a mild secretion of the external wound. No fistula had healed at that time.

At follow up after 6 months healing was achieved in 20 of the 40 patients (50.0%). Three additional fistulas healed after 7, 9 rsp. 12 months. The overall healing-rate was 57.5% (23/40). One patient, suffering from Crohn’s disease with complete healing after 6 months developed an abscess at 8 months postoperative with consecutive persistent fistula. So finally healing could be achieved in 22 of the 40 patients (57.5%). There was a high difference in healing rates between the surgeons ranging from 0% to 75% (Table 1 [Tab. 1]). Another difference occurred concerning previous surgical interventions (Table 1 [Tab. 1]): According to the type of surgical intervention healing occurred in 14 of 22 patients (63.6%) having had previous abscess excision or single plug procedure. Patients after previous advancement flap procedure of the fistula showed healing in 50% (9/18). Patients having had up to four previous interventions (including abscess excision) had healing in 66.7% (18/27). After more than four surgical procedures the rate was only 38.5% (5/13). Of the 12 suprasphincteric fistulas healing could be achieved in 5 patients (41.7%) (without patients with Crohn’s disease: 5 of 10 (50%)). In the group with transsphincteric fistulas (n=28) success could be observed in 18 patients (64.3%) (without patients with Crohn’s disease 16 out of 26 (61.5%)).

Postoperatively 22 patients had parenteral nutrition by central vein catheter or nutrition by resorbable diet. In these patients healing was observed in 16 patients (73.0%). In the 18 patients with enteral liquid or normal nutrition healing was achieved only in seven patients (38.9%).

Of the four patients with Crohn’s disease two achieved healing at 6 months, but one of these experienced a re-abscess at 8 months. The healing rate for non-Crohn patients therefore was 21/36 patients (58.3%).

No patient had a change of continence postoperatively.

Preoperative placement of a seton seems to have a positive effect on the healing of the fistula (healing in 13 of 21 patients (61.9%) with a seton; 8 of 15 (53.3%) without a seton (only non-Crohn patients).

For many years therapy of anal fistulas consisted of two main options: fistulotomy (lay open) and advancement flap procedure of the anal sphincter. The drainage by a seton can be used as a simple drain (long term seton) or as a cutting seton. Lay open as a complete transection of the tissue between fistula tract and anoderm has a very high success rate of up to 100%. In case of a superficial fistula it is the therapy of choice [7]. The incontinence rate after a lying open of intersphincteric and distal transsphincteric anal fistulas is under 10% [8] and predominantly of minor influence of quality of life. In cases of high (proximal) fistulas incontinence rates of 54% (type II) and 80% (type III) have been described [9].The extent of the continence disturbance depends on the mass of sphincter muscle that has been divided [9].

Therefore sphincter preserving procedures should be used in proximal transsphincteric and suprasphincteric fistulas [3]. The only really sphincter preserving therapy option for years has been the excision of the fistula and the reconstruction of the sphincter muscle using several types of flaps. It has been evaluated in many publications [10], [11]. The general principle of the procedure is the excision of the external part of the fistula up to the sphincter muscle, cautious excising the inflamed proctodeal gland tissue in the intersphincteric space and finally closing of the sphincter defect with several sutures and covering these sphincter sutures with an advancement flap. The healing rate of this procedure is 60–70%. There are no differences between the various techniques. Information about the incontinence rates varies between 0-70% in the different studies and depend highly on the accuracy of the evaluation [5], [12].

A recent procedure with similar even improved results is complete fistulectomy with primary reconstruction of the sphincter complex. In this case the fistulous tissue is completely excised including the surrounding scarred tissue. The divided parts of the sphincter are directly reconstructed with sutures [13], [14], [15].

A new option is the occlusion of the internal opening and the fistula tract with biomaterials. In 1991 the application of fibrin glue was described first [16]. The initially reported high healing rates without any negative effects on the sphincter [17], [18], couldn't be reproduced in further studies [19], [20], so this therapeutic option was abandoned.

Another operation technique was introduced in 2006 in the USA [21]. In contrast to conventional procedures where the excision of the fistula is the therapeutic principle, the fistula plug occludes the fistula with bioabsorbable materials. The initial cone plug consists of small bowel submucosa from a pig, which is replaced by human tissue by ingrowths of fibroblasts.

The excellent initial results of 70–85% [21], [22], couldn't be reproduced in recent randomized studies, that compared this technique with anorectal advancement flap procedures [4], [6]. An actual study [23] analyzes the impact of the length of the fistula to the success rate. Acceptable healing rates where reported at a minimum length of 4 cm. Below 4 cm the healing rate was only 21%, while it was 61% above 4 cm. A review [24] of the available studies states success rate of 24–92%. Realistically success rates between 20–30% can be achieved [4], [6]. The authors couldn't find an appreciable adverse effect on fecal continence. That is the exceptional strength of this procedure. A special problem of this plug is the anchorage in the fistula tract. A lot of failed attempts are due to a loss of the plug. And lastly the high costs of 500 € are only partly reimbursed in the German DRG System. A new code for this procedure (5–491.3) leads to a reimbursement of about 1500 € and is equal to simple fistulectomy.

Recently a completely new plug made of absorbable synthetic material was introduced. The plug is designed with a special flat disc head (Figure 1C [Fig. 1]), that makes it easier to fixate the plug at the internal opening and achieving better fixation by its new design and also by its greater volume of the implanted arms. Actually worldwide there are only three studies with results (Table 3 [Tab. 3]). In the first study [25] 12 patients with implanted pig-mucosal plugs (Cook-Fistula-Plug) are compared with 10 patients receiving 11 Gore Bio A Fistula Plugs. The operations took place between August 2007 and December 2009. Against this background the follow-up of 2 (Cook-plug) and 3 (Gore-plug) month is rather short. The healing rate, even with additional procedures, was 12.5% (2/16) procedures) in the pig-mucosa plug and 54.5% (6/11 procedures) in the synthetic absorbable plug group. This implicates a higher healing rate in the Gore-plug group. The two other studies observed healing rates between only 16% [26] and 73% [27].

Primarily it has to be stated, that this study presents preliminary results of a heterogenous group. But as today’s evolution of new products is running fast, every experience needs to be evaluated.

We present initial results from three German surgical units with the Gore-Plug. Of course, the results have to be interpreted very carefully due to the heterogenity of the patients group (different units and surgeons, different types of fistulas). One very interesting point seems to be the different result between the surgeons with healing rates from 0 to 75%. This fact shows the problem of different studies dealing with this treatment. Although all surgeons have been experienced colorectal surgeons the typ of fistula may play an important factor for the success rate, so that every fistula should be managed by an individual management. The healing rate in Crohn fistulas was only 1 out of 4 (25.0%), whereas in non-Crohn fistulas a healing rate of 57.5% could be observed. Results were better in fistulas without any previous advancement flap procedure (63.6%) than in patients having had one or more advancement flap procedures by flap techniques (44.4%). Also the healing rate seems to be higher in patients with transsphincteric than suprasphincteric fistulas. We did not observe any negative impact on anal continence. From that point of view a plug procedure may be considered as a therapeutic option in high anal fistulas, especially with a fistula tract longer than 4 cm.

Some of the interventions described took place in the context of a pilot study where the clinics were provided with the plugs (Gore-BioA-Fistula-Plug) by the manufacturer Gore free of cost. The authors did not receive any direct payments or gratifications.