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64 Radio-Frequency Energy Delivery to the Anal Canal for the Treatment of Fecal Incontinence [2002년 7월 DCR] 2011-11-17 3832
 
Takeshi Takahashi, M.D., F.A.C.S.* Sandra Garcia-Osogobio, M.D.Miguel Angel Valdovinos, M.D., Wilbert Mass, M.D., Ramiro Jimenez, M.D.,Luis Alfonso Jauregui, M.D., Juan Bobadilla, M.D., Carlos Belmonte, M.D.,Peter S. Edelstein, M.D., David S. Utley, M.D.
 
From the Service of Colon and Rectal Surgery,Departments of Surgery,Gastroenterology,Anesthesiology,
and GI Endoscopy, Instituto Nacional de Ciencias Medicas Nutricion Salvador Zubiran, Service of Colon and Rectal Surgery, Hospital Central Militar, Mexico City, Mexico, and Department of Surgery, Stanford
University Medical Center and VA Palo Alto Health Care System, Palo Alto, California
 
PURPOSE: In this prospective study we investigated the feasibility, safety, and efficacy of radio-frequency energy delivery deep to the mucosa of the anal canal for the treatment of fecal incontinence.
METHODS: We studied ten patients with fecal incontinence of varying causes. All patients
underwent anoscopy, anorectal manometry, endorectal ultrasound, and pudendal nerve terminal motor latency testing at baseline and six months. The Cleveland Clinic Florida scale for fecal incontinence (Wexner, 0–20), fecal incontinence-related quality of life score, and Short Form 36 were administered at baseline, 1, 2, 3, 6, and 12 months. Using conscious sedation and local anesthesia, we delivered
temperature-controlled radio-frequency energy via an anoscopic device with multiple needle electrodes to create thermal lesions deep to the mucosa of the anal canal.
RESULTS: Ten females (age, 55.9 +/- 9.2 years; range, 44–74) were enrolled and treated. Median discomfort by visual analog scale (0–10) was 3.8 during and 0.9 two hours after the procedure. Bleeding occurred in four patients (14–21days after procedure), spontaneous resolution (n = 3) and anoscopic suture ligation (n = 1). At 12 months, the median Wexner score improved from 13.5 to 5 (P < 0.001), with 80 percent of patients considered responders. All parameters in the fecal incontinence-related quality of life were improved (lifestyle (from 2.3 to 3.4), coping (from 1.4 to 2.7), depression (from 2.2 to 3.5), and embarrassment (from 1.3 to 2.8); P < 0.05 for all parameters). Protective pad use was eliminated in five of the seven baseline users. At six months, there was a significant reduction in both initial and maximum tolerable rectal distention volumes. Anoscopy was normal at six months.
CONCLUSION: Radio-frequency energy delivery to the anal canal for treatment of fecal incontinence
is a new modality that, in this study group, safely improved Wexner and fecal incontinence-related quality of life scores, eliminated protective pad use in most patients, and improved patient quality of life.
 
Fecal incontinence (FI) affects between 2 and 8 percent of U.S. adults. Causes include the presence of sphincter defects caused by trauma, surgery, or vaginal childbirth, congenital abnormalities, chronic diarrhea or constipation, pudendal neuropathy, and specific systemic medical diseases. The stigmata associated with FI are severe, often resulting in a dramatic reduction in patient quality of life (QOL).
 
Fecal incontinence management often begins with nonsurgical interventions, including diet modification,
antimotility agents, Kegel exercises, biofeedback, or controlled evacuation. Surgical management may be an option for patients with insufficient response to, or inability to cooperate with, conservative
modalities. Surgery is tailored according to the specific cause of FI and patient anatomy, and most commonly involves overlapping sphincter repair. Other techniques have been used, but are used less often, including the Thiersch procedure, stimulated gracilis muscle flap, posterior sphincter repair, and reefing procedures. New technologies being evaluated include artificial bowel sphincter implantation and sacral nerve stimulation.
 
A minimally invasive, endoanal outpatient procedure that reduces the involuntary passage of liquid
and solid stool would be of potential benefit to patients, particularly if performed under local anesthesia.
Based on the therapeutic effect of temperaturecontrolled radio-frequency (RF) energy delivery to the
lower esophageal sphincter for the treatment of gastroesophageal reflux disease, we hypothesized that
delivery of RF energy to the anal canal could potentially improve the barrier function of the anal sphincter
complex. This premise is based on the tissue tightening effects that occur with RF heating: collagen
contraction, focal wound healing, remodeling, and tissue compliance reduction. RF energy has been
used effectively for tightening tissue in obstructive sleep apnea, snoring, benign prostatic hyperplasia,
and joint capsule laxity. The purpose of this study was to evaluate the safety, tolerability, and effectiveness of RF energy delivery deep to the mucosa of the anal canal for the treatment of FI.
 
DISCUSSION
In this prospective study of a new application of temperature-controlled RF energy for fecal incontinence,
we demonstrated significant improvement in the Wexner and FIQL scores, elimination of protective
pad use in most patients, and improvement in patient quality of life. An unexpected reduction in the initial
rectal sensation volume and maximum tolerable rectal distention volume was noted, indicating a potential mechanism of action requiring further study. We included a group of patients with long-standing FI symptoms, confirmed by survey scores, who had failed standard nonsurgical measures for managing FI.
 
The current options available to patients with FI are limited to lifestyle management, medical therapy,
biofeedback, and surgery. Conservative measures have limited success because of compliance, and surgery may be offered to a select population of those who fail such measures. The most commonly used surgical technique for FI is overlapping sphincter repair, often with adjunctive levator muscle plication. This procedure is most effective in selected patients with anterior sphincter defects. Although typically safe and well-tolerated, sphincter repair requires specialized surgical skills, general or spinal anesthesia, hospitalization (ranging from 1 to14 days), and significant time for recovery. Perioperative complications are reported in up to 24 percent of cases, and include prolonged wound healing, infection, bleeding, fecal impaction, perineal sinus tract formation, and difficulty voiding.Published response rates for overlapping sphincter repair range from 69 to 93 percent. Pudendal neuropathy has been shown to be predictive of a less effective result from sphincter repair.
 
Other techniques are currently being evaluated that include implantation of either a sacral nerve stimulator or an artificial sphincter. Early experience with these devices is promising, yet complications associated with the implanted devices have occurred frequently and include infection, extrusion, and pain. The safety and tolerability of RF delivery to the anal canal in this study was notable for one bleeding episode that required intervention. This may have been related to mucosal injury with resultant eschar slough caused by insufficient cooling during treatment. Mucosa was intact in all patients, however, and normal in appearance at the six-month anoscopy. Some patients experienced temporary
worsening of FI symptoms in the first few weeks immediately after treatment, attributed to edema, serous drainage, and mucosal healing, after which time progressive improvement in FI symptoms occurred. No other adverse events were observed, no significant pain was incurred, and the recovery process was uneventful. Because this procedure was performed on an outpatient basis under local anesthesia, hospitalization and general anesthesia were avoided. Additionally, because the procedure
does not involve the implantation of a foreign body, there were no infection or extrusion complications.
 
The efficacy of this procedure was assessed using widely used survey instruments for FI (Wexner and
FIQL), protective pad use, and general quality of life (SF-36). The Wexner and FIQL scores were significantly improved, often beginning after the one-month follow-up. Improvement continued out to 12 months, in parallel with the timing of normal wound healing. Significant improvement was also seen in Questions 1 and 2 of the Wexner Score, indicating that some patients still experience gas incontinence, yet much of the solid and liquid stool incontinence is improved. This improvement in the Wexner score is comparable to published results of the efficacy of overlapping sphincter repair.
 
The improvement in SF-36 scores, although not statistically significant, was nonetheless present. The
social function parameter of the SF-36, typically affected by FI symptoms, was significantly improved at
6 and 12 months after this procedure. The SF-36 is an instrument for general, nonspecific QOL, and therefore may be affected by comorbid states. There were no significant changes in ERUS at six months, consistent with the microscopic nature of these lesions and previous ERUS findings from an animal protocol.
 
There are three possible mechanisms that may explain the observed therapeutic effect of RF energy
delivery for FI. First, heating of tissue to approximately 65°C results in an immediate linear contraction
of collagen protein to 25 to 33 percent of its initial length, with subsequent tissue shrinkage. Furthermore,
as normal wound healing processes commence, thermal lesions are replaced by fibroblasts and collagen and are then remodeled over a period of up to 12 months. The net effect is shrinkage of the
treated tissue, as observed in the treatment of snoring and obstructive sleep apnea, benign prostatic hyperplasia, and joint capsule laxity. This thermal effect reduces tissue compliance, as described in the
use of RF for the treatment of gastroesophageal reflux disease. A compliance change can have an effect on the barrier function of the sphincter, without a concomitant increase in basal pressure.
 
A second possible mechanism is that RF treatment of the upper portion of the anal canal, including the
transition zone, is related to the observed reduction in the ARM rectal distention volumes. Subjects were able to sense the initial distention at lower volumes and were able to tolerate much lower maximum volumes of rectal distention. This may result in earlier sensing of an impending FI event, and provide additional time to reach the lavatory.
 
A third possible mechanism may be related to alteration of the sampling reflex. If a sampling reflex exists, as described by Miller et al., and if this reflex contributes to FI in some patients, then RF may alter the sampling pattern and reduce FI symptoms, although the rectoanal inhibitory reflex remained intact in all patients.
 
The promising results of this trial should be considered in light of its potential limitations, including the
nonrandomized study design, the small number of subjects, and the subjective nature of the questionnaire scoring. Although a placebo effect is possible, the persistence of symptom score improvement with repeated measures analysis over a period of 12 months makes a significant placebo effect unlikely.
 
We speculate that the ideal future candidate for this procedure may have at least weekly incontinence and is dissatisfied with medical therapy, but is not willing to undergo or is not eligible for surgical intervention. Previous overlapping sphincter repair will not likely be an exclusion criterion, nor will pudendal neuropathy. Patients with a single anterior sphincter defect will likely to be offered surgery as first line treatment. Further, patients with diarrhea or constipation as a sole cause of FI are unlikely candidates for RF treatment. We recognize that further study regarding durability, subgroup analysis,
mechanism of action, and dosimetry may result in our needing to refine our present opinion.