fistula in ano, fistulotomy, radio frequency [rf] surgery, recurrence
P Gupta. Radio Frequency Fistulotomy: An Effective Modification Of The Conventional Technique. The Internet Journal of Surgery. 2002 Volume 4 Number 1.
Background: The techniques in vogue for treating fistula are fistulectomy, fistulotomy, curettage of fistula, and placement of flaps of mucosa or skin, placement of medicated Setons, insertion of antibiotic beads, and injection of commercial or autologous fibrin glue. Of all these procedures, majority of the surgeons continue to prefer the classical lay open technique [fistulotomy] as the procedure of choice in 90% of anal fistulae.
Materials & Methods: In this retrospective study, the conventional "lay open" technique, or "fistulotomy" has been performed by employing the radio frequency surgical device as an alternative to the traditional knife and scissors. In a span of 18 months starting from July 1999 to December 2000, 210 cases of fistula in ano of low variety were operated exclusively applying the radio frequency device.
Observations: A follow up of the operated patients with radio frequency surgery over a period of 15 months, i.e. from December 2000 to March 2002 could be summarized as below.
A] Average time taken by the patient to resume routine - 7 days.
B] None of the patient had any interference with anal continence.
C] The wounds were found healed within an average time of 47 days.
D] Delayed wound healing was noticed only in 7 patients.
E] Recurrence/ failure rate was as low as 1.5 percent.
Conclusion: This technique has been found superior to the conventional fistulotomy in the sense that the time taken for the whole procedure was reduced to almost half, amount of bleeding was minimum, the post operative pain was less compared to conventional method and return to work was much quicker.
Fistula in ano is defined as an abnormal communication lined by granulation tissue between the anal canal and the exterior i.e. the skin, which causes a chronic inflammatory response.
Etiology- The most common cause is secondary to an anorectal abscess. These abscesses either have been treated inadequately, or have bursts spontaneously. Abscess is commonly formed secondary to infection of an anal gland [cryptoglandular hypothesis of Eisenhammer .
Other causes are
Secondary to inflammatory bowel disease- Crohn's or Ulcerative proctocolitis.
Secondary to introduction of a foreign body e.g. probing of an abscess or a low fistula.
Associated with anal fissure, i.e. post fissure fistula.
Ca.Rectum especially the Colloid carcinoma.
Causes of multiple fistulae
T.B, Crohn's disease,
Bilharziasis, Hidradenitis suppurutiva etc.
Discharge- seropurulent, persistent, causing pruritus & discomfort in the surrounding skin .
Pain if the fistula tract is blocked – accumulation of secretions under pressure.
The external opening can usually be seen as an elevation of granulation tissue often active with purulent discharge. The number and location of external openings and the relationships to the anal canal provide a clue as to the internal origin. According to Goodsall's rule, if the opening is anterior to a transverse anal line (coronal plane), the internal opening will be in a direct radial line to the nearest crypt. If the  opening is posterior to the coronal line, the internal opening will usually be in a posterior midline crypt, and the tract will be curved. Exceptions to Goodsall's rule include anterior openings that are more than 3 cm from the anal margin and multiple openings. In these situations, the internal opening is more likely to be located in one of the posterior crypts. Other clinical conditions can simulate the appearance of a fistula, including hidradenitis suppurativa, pilonidal sinus, and Bartholin's gland abscess or sinus .
Palpation may reveal an indurated cord beneath the skin in the direction of the internal opening . Digital anal palpation may reveal a suspicious scarred or retracted crypt. Further internal palpation may reveal posterior or lateral induration, indicating fistulas deep in the postanal space or horseshoe fistulas. Digital rectal examination also provides assessment of sphincter tone and voluntary squeeze pressure, which may indicate the need for preoperative manometry.
It may aid in identifying the internal opening in the anal canal. Massaging the tract may produce a bead of pus at the dentate line. Proctosigmoidoscopy may exclude a proximal internal opening, inflammatory bowel disease, or neoplasia. Colonoscopy is appropriate if the diagnosis of Crohn's disease is suspected based on a history of recurrent or multiple fistulas or if examination is suggestive of inflammatory bowel disease. A small-bowel series also may be appropriate for patients with recurrent or multiple fistulas.
This may have a role in evaluation of recurrent fistula, particularly when the prior surgical procedure has failed to identify the internal opening. The external opening is cannulated with a small caliber feeding tube, and contrast material is gently injected into the tract. X-ray images are then taken in the anteroposterior, oblique, and lateral positions. Complications are rare, and limiting the volume and pressure of contrast injection can minimize patient discomfort. Accuracy rates have been reported to range from 16 to 48 percent, with a false-positivity rate of 10 percent .
There are four main types described. 1 Transphincteric low 2. Transphincteric high. 3.Supra-levator and 4. Intersphincteric. However, numerous variations of each can occur .
The classical lay open technique is still the most favored procedure . Slitting the complete tract from the external to internal opening is the basis of the traditional fistulotomy. Tissues around the external openings and internal opening are excised along with a small margin of tissue lining the tract and the wound is kept open for healing by secondary intention.
The traditional approach is as follows- 
Preoperative cleansing enema is given. The patient is kept in Lithotomy position.
General or regional block.
Digital palpation- The tract is felt as nodule or cord.
Proctoscopy- A hypertrophied anal papilla may be the point of internal opening.
Probing- It is done with delicate hand either retrograde [preferred] or anterograde.
Methylene blue dye or milk with hydrogen peroxide is injected from the external opening to locate the direction and path of the tract .
A director probe is inserted inside the fistula.
Track is cut along probe.
Edges of wounds trimmed. 1-3 mm of tissue margins removed.
The excised tract is sent for H.P. examination.
This conventional procedure encounters a lot of bleeding from the cut surfaces needing multiple ligatures to tie the bleeding vessels. At times, certain raw areas, which cannot be tied individually, may need under-running also. Due to all these hindrances, the whole procedure becomes somewhat messy and time consuming.
Materials and Methods
In our study, we have used the radio frequency surgical device instead of the surgical knife and scissors. The device is called as the Ellman Dual Frequency 4MHz unit by Ellman International, Hewlett, N.Y.
In a span of 18 months starting from July 1999 to December 2000, 210 cases of fistula in ano of varied types have been operated in our hospital exclusively employing the aforesaid radio frequency surgery device. There were 187 males and 23 females. The mean age was 37 yrs [range between 22yrs and 63 yrs]. The mean duration of the disease was 19 months [ranging from 4months to 11yrs]. Seventeen patients had an operation for fistula once before and they had come with a recurrence.
Radio frequency surgery is a technique for cutting and coagulating the tissues using a high frequency alternate current. It is a method of coagulating the tissues, which occurs because of heat produced by the tissue resistance to the passage of high frequency wave. The heat makes the intracellular water boil, increasing the cell inner pressure to the point of breaking it from inside to outside [explosion] . This phenomenon is called as cellular volatilization. The principle of radio frequency wave surgery is using high frequency radio waves at 4.0 MHz, which delivers low temperature through RF micro-fiber electrodes and is similar to the frequency of marine band radio frequencies. The tissue serves as the resistance instead of the electrode; hence, there is no heating of the RF micro-fiber electrode. Instead, the intracellular tissue water provides the resistance and vaporizes without causing the heat and damage seen in electro surgery. This tissue vaporization also results in significant hemostasis without actually burning the tissue. In addition, there is no danger of shocking or burning the patient. Most important is the fact that there is controlled and minimal lateral tissue damage with the 4.0 MHz high frequency, low temperature radio frequency wave surgery .
The unit is provided with a handle to which different electrodes can be attached as per the requirement of the procedure. A ball electrode meant for coagulation, a needle electrode to incise the fistula tract and round loop electrode to shave the surrounding infected tissue has been used in our procedure.
All the patients under study were given to understand the use of the new technique to be employed in the procedure and were clearly explained the potential drawbacks like relapses and need for repetition that may follow. An informed consent was obtained from them before subjecting them to this new technique. The local ethical committee approved the trail.
The exclusion criteria of the study were
Only low fistulas having opening below the ano rectal ring were included for study. High trans sphincteric fistulas with or without high blind tract, suprasphincteric, extrasphincteric, and horseshoe fistulas as well as fistulas associated with inflammatory bowel disease were excluded from the study.
Radio frequency surgical Fistulotomy procedure
The steps in the fistulotomy  are the same as described above with the following modifications.
Injection of methylene blue dye with hydrogen peroxide.
Director probe inserted in the fistula.
To begin with, the skin overlying the probe, which was in the fistula tract, was coagulated by moving the ball electrode over its complete length. This reduced the amount of bleeding when the tract was slit opened.
The track was cut open along the probe with the help of the needle electrode that was kept in cutting and coagulation mode. This reduced the bleeding while cutting, and the dissection becomes smooth without a drag on the tissues.
The bleeding edges were caught in the hemostat and were coagulated with the ball electrode kept in coagulation mode. This avoided need of suturing or under running of the bleeding points and raw areas.
The edges along with the surrounding infected, fibrotic tissues were shaved with the loop electrode on cut and coagulation mode. As cutting and coagulation works simultaneously, the brisk bleeding often encountered in the conventional knife and scissor dissection was avoided.
At this stage, we have used an accessory called the suction coagulator. This is an accessory supplied with the radio frequency surgical device. This helps in removing the ooze of blood from the raw area while the bleeding points are being coagulated. The use of this additional tool eliminates frequent mopping of the operative field while coagulating the bleeding point, as both can be done simultaneously.
Apart from the main procedure of fistulotomy, this radio frequency surgical device could also be used in coagulating associated skin tags, and internal pile masses if present.
Post operative care
This consists of dressing the wound twice a day after warm sitz bath. The patient was discharged on the very next day of the procedure. Time off work was between 5-7 days after which patient could resume his routine.
A follow up of the operated patients of fistulotomy with radio frequency surgery over a period of 15 months, i.e. from December 2000 to March 2002 was as follows.
No. of patients lost during follow up- 9.
Average time taken for complete wound healing- 47 days.
Average time taken by the patient to resume routine – 7 days.
Delayed wound healing in 7 patients. [Took about 80-90 days for complete healing]. It was observed that the fistula wounds which were close to the midline, i.e., near 12 or 6'O clock positions when the patient is in lithotomy position took longer time to heal than wounds at other places. The reason possibly could be an excess of stress on the wounds in that situation due to proximity with joints.
Four patients had a premature closure of the proximal wound while the distal remained unhealed. In case of these patients, the healed edges of the proximal wound were slit opened with needle electrode under local anaesthesia. One of them thereafter had an uneventful healing, while the wound remained unhealed in the remaining three.
The remaining three patients continued to have discharge from a small wound left behind, which despite repeated attempts of refreshioning the edges remained unresolved. So, they were labeled as cases of ‘failure of wound healing', rather than of recurrence. Out of these three patients, one patient was from the series of those seventeen patients who came with a recurrence after conventional procedure in the past.
None of the patient had any interference with the continence. None had developed anal stenosis, or mucosal prolapse. 
The data of follow up findings is given in Fig. 1.
Failure occur mainly due to premature union of the skin edges, failure to excise the internal opening, failure to locate an extra tract, failure to detect a cavity leading upwards from the main tract, presence of foreign bodies and poor post fistulotomy wound care . In our study, the failure rate was as low as 1.5%.
No major complications were encountered. Few minor ones are discussed below.
Deep dissection may cause more scarring and longer time for healing.
Excessive power of the unit can cause more smoke and charring.
Accidental burns either on the part of the patient or operator due to unintended activation of hand piece has been noted.
Development of edema in the surrounding tissue, if power is too high.
Few patients complained excessive discharge from the open wound. This usually happened when the tissues at the base were coagulated in excess.
Radio frequency surgery, not to be confused with electro surgery, diathermy, spark-gap circuitry, or electrocautry, uses a very high frequency radio frequency wave. Unlike electrocautry or diathermy, the electrode remains cold . This is possible because of use of very high frequency current of 4 MHz, as compared to 0.5 to 1.5 MHz used in the electrocautry. As contrast to true cautery, which causes damage similar to 3rd degree burns, the tissue damage that does occur is very superficial and is comparable to that which occurs with Lasers. Histologically, it has been shown that tissue damage with radio frequency surgery is actually less than with a conventional scalpel and equals cold scalpel . Radio frequency surgery creates minimal collateral heat damage in the tissue resulting in rapid healing and leaves no ugly scar. Biopsies performed of the skin tissue indicate a maximum thickness of heat-denatured collagen to be 75 micrometer. This is equal to or even better than carbon di oxide laser used for cutting .
Rapidity of treatment, a nearly bloodless field, minimal postoperative pain, and rapid healing are but few advantages of radio frequency surgery. Once proper technique is established, a scar by this method of treatment is often less pronounced than those produced by other surgical techniques. Excising too deeply increases the likelihood of scars .
Precautions to be taken
Removing a lesion on someone who is on aspirin or anticoagulant therapy may be accompanied by increased bleeding.
The unit should not be used in presence of flammable or explosive liquids or gases. The surgeon must also remember to deactivate the hand piece whenever the electrodes are changed .
As with all radio frequency surgery machines, smoke is produced, this needs to be attended to avoid the unpleasant smell of burning. This could be achieved by employing a vacuum extractor with the help of the assistant .
The various techniques used for treating fistula  are fistulectomy, fistulotomy, fistulotomy with marsupialisation  of fistula, curettage of fistula and placement of flaps of mucosa or skin, placement of medicated Setons, insertion of antibiotic beads, and injection of commercial or autologous fibrin glue . Out of these options available to the surgeon, majorities of them still rely on the classical lay open technique [fistulotomy] as the gold standard of treatment in over 90% of anal fistula cases .
Patient satisfaction after surgical treatment for fistula-in-ano is associated with recurrence of the fistula, the development of anal incontinence, and the effects of anal incontinence on patient lifestyle . The radio frequency surgical technique of fistulotomy has been found more acceptable than the conventional fistulotomy in the sense that the time taken for the whole procedure is reduced to half, bleeding is reduced to a minimum and the use of suture material is dispensed with. None of the patient in our study had any interference with the continence and the recurrence rate was as low as 1.5%.
If compared to electrocautery or laser, the active electrode does not heat up, so there is minimal or no heat generated to the surgical site. This allows the surgeon to work in direct proximity of the functional tissues that needs to be preserved .