Injectable synthetic calcium hydroxylapatite ceramic microspheres (Coaptite) for passive fecal incontinence

An evaluation of the long-term effectiveness of Gatekeeper™ intersphincteric implants for passive faecal incontinence

Background

Implantation of Gatekeeper™ prostheses presents an option for the treatment of passive faecal incontinence (FI). Whilst preliminary results are encouraging, long-term data regarding its sustained benefit are limited. The aim of this study was to assess and evaluate the long-term clinical function and quality of life of patients with passive faecal incontinence who were treated with Gatekeeper™ prostheses.

Methods

This was a single centre, single surgeon retrospective study of prospectively collected clinical data in patients with FI treated between June 2012 and May 2019. Patients with passive FI with symptoms refractory to conservative treatment and endoanal ultrasonography showing intact or disrupted internal anal sphincter were included. Formal clinical and quality of life assessments were carried out using the St. Mark’s Incontinence Score (SMIS) and Faecal Incontinence Quality of Life (FIQoL) questionnaires at baseline, 3 months, 6 months, 12 months and then annually. Endoanal ultrasonography was performed both before and after surgery.

Results

Forty patients (14 males, 26 females) with a median age of 62.5 (range 33–80) years were treated with the Gatekeeper™ implant. The majority of patients (87.5%) received six implants. There were no peri or post-operative complications. Prosthesis migration was observed in 12.5% patients. The median follow-up duration was 5 years (interquartile range (IQR) 3.25–6.00 years). A sustained improvement in median SMIS and FIQoL scores from baseline to follow-up was noted. Significant differences were observed between the median baseline SMIS score and last follow-up score of 16.00 (IQR 15.00–16.75) to 7.00 (IQR 5.00–8.00) respectively (p < 0.001), a 56.25% decrease. The overall median FIQoL score showed a significant improvement from 7.95 (IQR 7.13–9.48) to 13.15 (IQR 12.00–13.98) (p < 0.001) a 65.40% increase.

Conclusions

Gatekeeper™ implantation is a safe approach to treating passive FI and is minimally invasive, reproducible and has minimal complications. Long-term sustained clinical improvement is achievable beyond 5 years. Careful patient selection is paramount, as is consistency of technique and follow-up protocol.

Midterm outcomes of injectable bulking agents for fecal incontinence: a systematic review and meta-analysis

BACKGROUND

Various bulking agents have been used to treat fecal incontinence. While short-term outcomes are attractive, there is still a lack of long-term data. The aim of this systematic review and meta-analysis was to investigate the midterm outcomes of treatment with injectable bulking agents and to identify predictive factors for improvement in incontinence.

METHODS

PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched using the terms injection, bulking agents, and fecal incontinence. Studies with a minimum follow-up of 1 year were included. The improvement rate in incontinence was calculated by percent change in validated fecal incontinence score (FIS) following injection treatment. To explore the impact of predictive factors on improvement in incontinence, univariate meta-regressions were conducted using the random-effect model.

RESULTS

A total of 889 patients in 23 articles were included. The weighted mean follow-up duration was 23.7 months (95% CI 19.3-28.2). Eleven different bulking agents were used. Four validated FISs were used. The Cleveland Clinic Fecal Incontinence score (CC-FIS) was used in 19 studies. Most studies reported a statistically significant improvement in FIS. The pooled mean preoperative CC-FIS (n = 637) was 12.4 (95% CI 11.4-13.3). The pooled mean CC-FIS at last follow-up (n = 590) was 7.7 (95% CI 6.1-9.3). The weighted mean difference in CC-FIS between preoperative visit and last follow-up was 4.9 (95% CI 4.0-5.8). Hence, the rate of improvement in incontinence was 39.5% based on CC-FIS. Meta-regression revealed that the perianal injection route and implants intact on endoanal ultrasonography were predictive of greater improvement in incontinence. The manometric data revealed that the initial increase in the mean resting pressure following injection was attenuated over time. The pooled rate of adverse events was 18.0% (95% CI 10.0-30.1). In most cases, adverse events were minor and resolved within a couple of weeks.

CONCLUSIONS

Administration of injectable bulking agents results in significant midterm improvement in FIS. Perianal injection route and implants intact on EAUS were predictive of higher improvement in incontinence. However, given the paucity of randomized controlled trials in the literature, further research is needed to improve the quality of the evidence.

Multicentre observational study of the Gatekeeper for faecal incontinence

Background

A variety of therapeutic approaches are available for faecal incontinence. Implantation of Gatekeeper™ prostheses is a new promising option. The primary endpoint of this prospective observational multicentre study was to assess the clinical efficacy of Gatekeeper™ implantation in patients with faecal incontinence. Secondary endpoints included the assessment of patients' quality of life, and the feasibility and safety of implantation.

Methods

Patients with faecal incontinence, with either intact sphincters or internal anal sphincter lesions extending for less than 60° of the anal circumference, were selected. Intersphincteric implantation of six prostheses was performed. At baseline, and 1, 3 and 12 months after implantation, the number of faecal incontinence episodes, Cleveland Clinic Faecal Incontinence, Vaizey and American Medical Systems, Faecal Incontinence Quality of Life Scale and Short Form 36 Health Survey scores were recorded. Endoanal ultrasonography was performed at baseline and follow‐up.

Results

Fifty‐four patients were implanted. After Gatekeeper™ implantation, incontinence to gas, liquid and solid stool improved significantly, soiling was reduced, and ability to defer defaecation enhanced. All faecal incontinence severity scores were significantly reduced, and patients' quality of life improved. At 12 months, 30 patients (56 per cent) showed at least 75 per cent improvement in all faecal incontinence parameters, and seven (13 per cent) became fully continent. In three patients a single prosthesis was extruded during surgery, but was replaced immediately. After implantation, prosthesis dislodgement occurred in three patients; no replacement was required.

Conclusion

Anal implantation of the Gatekeeper™ in patients with faecal incontinence was effective and safe. Clinical benefits were sustained at 1‐year follow‐up.

Gatekeeper^TM effective

Myoblast differentiation on growth factor-immobilized polycaprolactone microparticles: a potential bioactive bulking agent for fecal incontinence

Fecal incontinence (FI), caused by damage or weakness of the anal sphincter, is a devastating problem for patients experiencing the symptom. Although injectable bulking agents are accepted as a minimally invasive therapeutic technique to treat FI, their short-term efficacy and inability to enhance the anal sphincter function are considered as challenges in clinical practices. In this study, growth factor [nerve growth factor (NGF) and/or basic fibroblast growth factor (bFGF)]-immobilized polycaprolactone (PCL) microparticles were prepared as an injectable bioactive bulking agent that can provide a bulking effect (by microparticles) and stimulate myoblast differentiation or injured muscles around the anus (by the sustained release of growth factors) to enhance the sphincter function for the effective treatment of FI. Pluronic F127-entrapped PCL microparticles were prepared by an isolated particle-melting method. Two different growth factors (NGF and bFGF) were incorporated on the surfaces of the Pluronic F127-entrapped PCL microparticles via heparin binding. The growth factors immobilized on the microparticles were released in a sustained manner over 4 weeks. From cell cultures on the growth factor-immobilized microparticles, it was observed that the myoblasts adhered on the microparticle surfaces showed differences in differentiation into myotubes depending on the growth factor type. In particular, the dual NGF/bFGF-immobilized microparticle group was effective for myogenic differentiation in comparison with the single growth factor (NGF or bFGF)-immobilized groups. The dual NGF/bFGF-immobilized microparticles are suitable to be applied as an injectable bulking agent for the treatment of FI.

Long-term efficacy of NASHA Dx injection therapy for treatment of fecal incontinence

BACKGROUND

Injectable bulking treatment for fecal incontinence (FI) is intended to expand tissue in the anal canal and prevent fecal leakage. Use of injectable bulking agents is increasing because it can be performed in an outpatient setting and with low risk for morbidity. This study evaluated the long-term (36-month) clinical effectiveness and safety of injection of non-animal stabilized hyaluronic acid/dextranomer (NASHA Dx) on FI symptoms.

METHODS

In a prospective multicenter trial, 136 patients with FI received the NASHA Dx bulking agent. Treatment success defined as a reduction in number of FI episodes by 50% or more compared with baseline (Responder50 ). Change from baseline in Cleveland Clinic Florida Fecal Incontinence Score (CCFIS) and Fecal Incontinence Quality of Life Scale (FIQL), and adverse events were also evaluated.

KEY RESULTS

Successful decrease in symptoms was achieved in 52% of patients at 6 months and this was sustained at 12 months (57%) and 36 months (52%). Mean CCFIS decreased from 14 at baseline to 11 at 36 months (p < 0.001). Quality-of-life scores for all four domains improved significantly between baseline and 36 months of follow-up. Severe adverse events were rare and most adverse events were transient and pertained to minor bleeding and pain or discomfort.

CONCLUSIONS & INFERENCES

Submucosal injection of NASHA Dx provided a significant improvement of FI symptoms in a majority of patients and this effect was stable during the course of the follow-up and maintained for 3 years.

Current status: new technologies for the treatment of patients with fecal incontinence

Fecal incontinence is a frequent and debilitating condition that may result from a multitude of different causes. Treatment is often challenging and needs to be individualized. During the last several years, new technologies have been developed, and others are emerging from clinical trials to commercialization. Although their specific roles in the management of fecal incontinence have not yet been completely defined, surgeons have access to them and patients may request them. The purpose of this project is to put into perspective, for both the patient and the practitioner, the relative positions of new and emerging technologies in order to propose a treatment algorithm.

Internal anal sphincter augmentation and substitution

There is an increasing recognition of the importance of internal anal sphincter (IAS) dysfunction presenting as passive faecal incontinence. This problem may manifest after anal sphincterotomy or following the more minimally invasive operations for haemorrhoids, as well as with advancing age. Because of the poor results of IAS plication and the beneficial outcomes with peri-urethral bulking agents in urology, these materials have been developed for use in IAS dysfunction. This review outlines the basic purported mechanisms of action, defining the materials in clinical use, their methods of deployment, complications and reported outcomes. There is still much that is unknown concerning the ideal agent or the volume and the technique of deployment, which will only be answered by powerful, prospective, randomized, controlled trials. The specific role of autologous stem cells designed to regenerate the sphincters in cases of functional impairment or muscle loss is yet to be seen.

Injectable collagen for the treatment of fecal incontinence: long-term results

BACKGROUND

Fecal incontinence is a distressing condition that is difficult to treat. Injection of bulking agents has been used to treat passive fecal incontinence. However, no long-term results are available.

OBJECTIVE

The aim of this study was to assess the long-term clinical effectiveness of intra-anal injection of collagen for passive fecal incontinence.

DESIGN

This research is a retrospective cohort study from a prospectively collected database

SETTING

This investigation took place in a high-volume tertiary colorectal department.

PATIENTS

All patients who underwent intra-anal injection of collagen for passive fecal incontinence with internal sphincter dysfunction between January 2006 and December 2009 were included in the study. Data including demographic details, preoperative anorectal physiology, and outcome measures were collected prospectively and maintained in a database

MAIN OUTCOME MEASURES

The primary outcomes measured were the Cleveland Clinic Florida incontinence score and the responses to a subjective patient satisfaction questionnaire before the procedure and at subsequent follow-up visits. Data were analyzed by using SPSS v19.0.

RESULTS

One hundred patients (70 female; mean age, 61 years (range, 36-82)) were followed up for a minimum duration of 36 months. Fifty-six patients (56%) had an improvement in fecal incontinence score from a mean of 14 (range, 9-18) to a mean of 8 (range, 5-14). A total of 68% reported subjective improvement in symptoms. Thirty-eight patients (38%) required a repeat injection of collagen, and a further 15 patients required a third injection. The median interval between the first and final injection was 12 months (range, 4-16 months). Age was the only independent predictor of successful outcome (p = 0.032). There was no morbidity.

LIMITATIONS

This study was limited by its nonrandomized retrospective design.

CONCLUSIONS

Injection of collagen into the internal anal sphincter is simple, safe, and effective in patients with passive fecal incontinence, although repeat injections are necessary in approximately half of the patients.

Perianal injectable bulking agents as treatment for faecal incontinence in adults

BACKGROUND

Faecal incontinence is a complex and distressing condition with significant medical and social implications. Injection of perianal bulking agents has been used to treat the symptoms of passive faecal incontinence. However, various agents have been used without a standardised technique and the supposed benefit of the treatment is largely anecdotal with a limited clinical research base.

OBJECTIVES

To determine the effectiveness of perianal injection of bulking agents for the treatment of faecal incontinence in adults.

SEARCH METHODS

We searched the Cochrane Incontinence Group Specialised Register of trials (25 May 2012), ZETOC (3 May 2012), clinical trials registries (3 May 2012) and the reference lists of relevant articles.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing the use of injectable bulking agents for faecal incontinence with any alternative treatments or placebo were reviewed to evaluate the therapeutic effects. Case-control and cohort studies were also reviewed to assess risks and complications associated with the treatments.

DATA COLLECTION AND ANALYSIS

Two review authors (YM and CN) assessed the methodological quality of eligible trials and independently extracted data from the included trials using a range of pre-specified outcome measures.

MAIN RESULTS

Five eligible randomised trials with a total of 382 patients were identified. Four of the trials were at an uncertain or high risk of bias.Most trials reported a short term benefit from injections regardless of the material used, including placebo saline injection. One study demonstrated dextranomer in stabilised hyaluronic acid (NASHA Dx) to be more effective than sham injection but with more adverse effects. Dextranomer in stabilised hyaluronic acid (NASHA Dx) was better than sham injections at six months (65/136, 48% versus 48/70, 69% participants not improved, defined as less than 50% reduction in incontinence episodes, RR 0.70, 95% CI 0.55 to 0.88; with more incontinence free days (3.1 days compared with 1.7 in the sham treatment group, MD 1.40 days, 95% CI 0.33 to 2.47). Another study comparing silicone material (PTQ™) to saline injections was too small to demonstrate a clinical benefit compared to the control injection of normal saline.A silicone biomaterial (PTQ™) was shown to provide some advantages and was safer in treating faecal incontinence than carbon-coated beads (Durasphere®) in the short term.Similarly, there were short term benefits from injections delivered under ultrasound guidance compared with digital guidance.No long term evidence on outcomes was available and further conclusions were not warranted from the available data. None of the studies reported patient evaluation of outcomes and thus it is difficult to gauge whether the improvement in incontinence scores matched practical symptom improvements that mattered to the patients.

AUTHORS' CONCLUSIONS

One large randomised controlled trial has shown that this form of treatment using dextranomer in stabilised hyaluronic acid (NASHA Dx) improves continence for a little over half of patients in the short term. However, the number of identified trials was limited and most had methodological weaknesses.

The use of Permacol® injections for the treatment of faecal incontinence

The aim of this study is to assess the safety and efficacy of Permacol(®) implant for the treatment of idiopathic faecal incontinence using a novel injection technique. Patients with idiopathic passive faecal incontinence were selected for trans-submucosal injection of Permacol(®) after assessment by anorectal physiology and endoanal ultrasonography. Clinical assessment and St. Mark's Incontinence Score were used to evaluate efficacy before and at two time points (1 and 2 years) after treatment. Rockwood Score were also used to determine quality of life before and after treatment. The Friedman and Chi-square tests were used to compare continuous and categorical data, respectively. A p value of <0.05 was deemed significant. Thirty-eight patients (24 female), median age 66 years, were recruited. At maximum clinical follow-up (median of 9 months), response to Permacol(®) injections was categorised as excellent, good, fair and poor in 12, 5, 4 and 17 patients, respectively. St. Mark's Score improved in 72 and 63 % of patients at 1 and 2 years, respectively. However, a smaller proportion of patients (39 and 27 %, respectively) achieved a 50 %, or more, improvement in Mark's Score. All four domains of Rockwood Quality of Life Score improved on first and second year follow-up, however, only two domains, coping and embarrassment, were statistically significant. Permacol(®) injection improved symptoms by >50 % in 39 and 27 % of patients on short and medium-term follow-ups, respectively. The trans-submucosal technique for injection of Permacol(®) in this study was safe with no significant adverse outcomes.

Treatment of fecal incontinence - review of observational studies (OS) and randomized controlled trials (RCT) related to injection of bulking agent into peri-anal tissue

PURPOSE: Novel treatments are needed to augment medical therapy for fecal incontinence. METHODS: Medline and Google search (fecal incontinence and injection treatment), English publications. RESULTS: Twenty-two observational studies and 4 randomized controlled trials were identified. OS mostly with limited sample sizes reported promising results. Repeated injection was necessary in some patients. Effect on anal sphincter pressures was highly variable. Significant improvements in the length of anal high-pressure zone, asymmetry index and maximum tolerable rectal volume were suggested. Four randomized controlled trials (n=176) revealed: 1. Short-term benefits from injection of Bioplastique under ultrasound guidance compared with digital guidance; 2. Silicone biomaterial (PTQ) provided some advantages and was safer than carbon-coated beads (Durasphere); 3. PTQ did not demonstrate clinical benefit compared to control injection of saline; 4. There was significant improvement at 6 weeks post injection, but no difference between Bulkamid and Permacol. A 2010 Cochrane review, however, noted that these data were inconclusive due to limited number and methodological weaknesses. CONCLUSION: Further studies are warranted to assess patient-centered outcomes (e.g. adequate relief) in addition to the attenuation of severity of incontinence symptoms in ambulatory patients. In nursing home residents, cost-effectiveness studies combining injection treatment and prompted voiding (to mitigate constraints of immobility and dementia) in preventing peri-anal skin complications deserves to be considered.

Systematic review of perianal implants in the treatment of faecal incontinence

BACKGROUND

Injectable bulking agents have been used with varying success for the treatment of faecal incontinence. This systematic review aimed to investigate the various injectable agents and techniques used for the treatment of faecal incontinence, and to assess their safety and efficacy.

METHODS

Thirty-nine publications were identified and studied. The following variables were pooled for univariable analysis: type, location, route of bulking agents, and the use of ultrasound guidance, antibiotics, laxatives and anaesthetics. Predictors of the development of complications and successful outcomes were identified by multivariable logistic regression analysis.

RESULTS

A total of 1070 patients were included in the analysis. On multivariable analysis, the only significant predictor of the development of complications was the route of injection of bulking agents (odds ratio 3·40, 95 per cent confidence interval 1·62 to 7·12; P = 0·001). Two variables were significant predictors of a successful short-term outcome: the use of either PTQ(®) (OR 5·93, 2·21 to 16·12; P = 0·001) or Coaptite(®) (OR 10·74, 1·73 to 65·31; P = 0·001) was associated with a greater likelihood of success. Conversely, the use of local anaesthetic was associated with a lower likelihood of success (OR 0·18, 0·05 to 0·59; P = 0·005). Failure to use laxatives in the postoperative period resulted in a poorer medium- to longer-term outcome (OR 0·13, 0·06 to 0·25; P = 0·001).

CONCLUSION

This systematic review has identified variations in the practice of injection of bulking agents that appear to influence the likelihood of complications and affect the outcomes after treatment.

Successful implantation of bioengineered, intrinsically innervated, human internal anal sphincter

BACKGROUND & AIMS

To restore fecal continence, the weakened pressure of the internal anal sphincter (IAS) must be increased. We bioengineered intrinsically innervated human IAS to emulate sphincteric physiology in vitro.

METHODS

We cocultured human IAS circular smooth muscle with immortomouse fetal enteric neurons. We investigated the ability of bioengineered innervated human IAS, implanted in RAG1-/- mice, to undergo neovascularization and preserve the physiology of the constituent myogenic and neuronal components.

RESULTS

The implanted IAS was neovascularized in vivo; numerous blood vessels were observed with no signs of inflammation or infection. Real-time force acquisition from implanted and preimplant IAS showed distinct characteristics of IAS physiology. Features included the development of spontaneous myogenic basal tone; relaxation of 100% of basal tone in response to inhibitory neurotransmitter vasoactive intestinal peptide (VIP) and direct electrical field stimulation of the intrinsic innervation; inhibition of nitrergic and VIPergic electrical field-induced relaxation (by antagonizing nitric oxide synthesis or receptor interaction); contraction in response to cholinergic stimulation with acetylcholine; and intact electromechanical coupling (evidenced by direct response to potassium chloride). Implanted, intrinsically innervated bioengineered human IAS tissue preserved the integrity and physiology of myogenic and neuronal components.

CONCLUSIONS

Intrinsically innervated human IAS bioengineered tissue can be successfully implanted in mice. This approach might be used to treat patients with fecal incontinence.

Efficacy of dextranomer in stabilised hyaluronic acid for treatment of faecal incontinence: a randomised, sham-controlled trial

BACKGROUND

Injection of a bulking agent in the anal canal is an increasingly used treatment for faecal incontinence, but efficacy has not been shown in a controlled trial. We aimed to assess the efficacy of injection of dextranomer in stabilised hyaluronic acid (NASHA Dx) for treatment of faecal incontinence.

METHODS

In this randomised, double-blind, sham-controlled trial, patients aged 18-75 years from centres in USA and Europe were randomly assigned (2:1) to receive either transanal submucosal injections of NASHA Dx or sham injections. Randomisation was stratified by sex and region in blocks of six, and managed with a computer generated, real-time, web-based system. Patients and investigators were masked to assignment for 6 months when the effect on severity of faecal incontinence and quality of life was assessed with a 2-week diary and clinical assessments. The primary endpoint was response to treatment based on the number of incontinence episodes. A response to treatment was defined as a reduction in number of episodes by 50% or more. Patients in the active treatment group are still being followed up. This trial was registered with ClinicalTrials.gov, number NCT00605826.

FINDINGS

278 patients were screened for inclusion, of whom 206 were randomised assigned to receive NASHA Dx (n=136) or sham treatment (n=70). 71 patients who received NASHA Dx (52%) had a 50% or more reduction in the number of incontinence episode, compared with 22 patients who received sham treatment (31%; odds ratio 2·36, 95% CI 1·24-4·47, p=0·0089). We recorded 128 treatment-related adverse events, of which two were serious (1 rectal abscess and 1 prostatic abscess).

INTERPRETATION

Anal injection of NASHA Dx is an effective treatment for faecal incontinence. A refinement of selection criteria for patients, optimum injected dose, ideal site of injection, and long-term results might further increase the acceptance of this minimally invasive treatment.

FUNDING

Q-Med AB.

Quality of life and functional results of submucosal injection therapy using dextranomer hyaluronic acid for fecal incontinence

BACKGROUND AND AIM

The aim of this prospective study was to analyze safety and functional outcome of transanal submucosal injection of dextranomer hyaluronic acid ("bulking agents therapy") in patients with passive fecal incontinence.

METHODS

All patients who underwent transanal injection therapy were prospectively enrolled in this study. Inclusion criteria included fecal incontinence (internal anal sphincter dysfunction) after failed conservative treatment. The procedure was performed in a standardized technique, including submucosal injection of 4 × 1 mL dextranomer hyaluronic acid 5 mm above the dentate line. The primary endpoint focused on symptom improvement provided as the change in incontinence status and quality of life using validated scores (Wexner incontinence score, symptom-specific Fecal Incontinence Quality of Life [FIQoL] scale, and generic EQ-5D-Visual Analogue Scale [EQ-5D-VAS]).

RESULTS

Within the observation period (July 2007 to May 2009), a total of 21 patients (17 women) with passive fecal incontinence were treated. Neither morbidity nor adverse events were documented. Three months postoperatively, 61.1% (11/18) showed significant improvement of symptoms (reduction of incontinence episodes and soiling), which was sustained after 20 months in 55.6% (10/18). Wexner incontinence score decreased from 16.8 to 12.3 (P > .05). Significant improvement was documented for FIQoL and EQ-5D-VAS (P < .05).

CONCLUSION

The current results indicate that injection therapy using hyaluronic acid is an innovative and minimally invasive procedure with no morbidity. Although Wexner incontinence score is not significantly influenced, a significant improvement in quality of life was observed in more than 50% of patients.

Successful implantation of physiologically functional bioengineered mouse internal anal sphincter

We have previously developed bioengineered three-dimensional internal anal sphincter (IAS) rings from circular smooth muscle cells isolated from rabbit and human IAS. We provide proof of concept that bioengineered mouse IAS rings are neovascularized upon implantation into mice of the same strain and maintain concentric smooth muscle alignment, phenotype, and IAS functionality. Rings were bioengineered by using smooth muscle cells from the IAS of C57BL/6J mice. Bioengineered mouse IAS rings were implanted subcutaneously on the dorsum of C57BL/6J mice along with a microosmotic pump delivering fibroblast growth factor-2. The mice remained healthy during the period of implantation, showing no external signs of rejection. Mice were killed 28 days postsurgery and implanted IAS rings were harvested. IAS rings showed muscle attachment, neovascularization, healthy color, and no external signs of infection or inflammation. Assessment of force generation on harvested IAS rings showed the following: 1) spontaneous basal tone was generated in the absence of external stimulation; 2) basal tone was relaxed by vasoactive intestinal peptide, nitric oxide donor, and nifedipine; 3) acetylcholine and phorbol dibutyrate elicited rapid-rising, dose-dependent, sustained contractions repeatedly over 30 min without signs of muscle fatigue; and 4) magnitudes of potassium chloride-induced contractions were 100% of peak maximal agonist-induced contractions. Our preliminary results confirm the proof of concept that bioengineered rings are neovascularized upon implantation. Harvested rings maintain smooth muscle alignment and phenotype. Our physiological studies confirm that implanted rings maintain 1) overall IAS physiology and develop basal tone, 2) integrity of membrane ionic characteristics, and 3) integrity of membrane associated intracellular signaling transduction pathways for contraction and relaxation by responding to cholinergic, nitrergic, and VIP-ergic stimulation. IAS smooth muscle tissue could thus be bioengineered for the purpose of implantation to serve as a potential graft therapy for dysfunctional internal anal sphincter in fecal incontinence.

Perianal injectable bulking agents as treatment for faecal incontinence in adults

BACKGROUND

Faecal incontinence is a complex and distressing condition with significant medical and social implications. Injection of perianal bulking agents has been used to treat the symptoms of passive faecal incontinence. However, various different agents have been used without a standardised technique and the supposed benefit of the treatment is largely pragmatic with a limited clinical research base.

OBJECTIVES

To determine the effectiveness of perianal injection of bulking agents for the treatment of faecal incontinence in adults.

SEARCH STRATEGY

We searched the Cochrane Incontinence Group Specialised Register of trials (searched 10 June 2009), ZETOC (searched 18 July 2009), clinical trials registries (searched 18 July 2009) and the reference lists of relevant articles.

SELECTION CRITERIA

All randomised or quasi-randomised controlled trials comparing use of injectable bulking agents for faecal incontinence with any alternative treatments or placebo were reviewed to evaluate the therapeutic effects. Case-control and cohort studies were also reviewed to assess risks and complications associated with the treatment.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed the methodological quality of eligible trials and independently extracted data from included trials using a range of pre-specified outcome measures.

MAIN RESULTS

Four eligible randomised trials were identified with a total of 176 patients. All trials but one were at an uncertain or high risk of bias. Most trials reported a short term benefit from injections regardless of the material used as outcome measures improved over time. A silicone biomaterial (PTQ), was shown to provide some advantages and was safer in treating faecal incontinence than carbon-coated beads (Durasphere(R)) in the short term. Similarly, there were short term benefits from injections delivered under ultrasound guidance compared with digital guidance. However, PTQ did not demonstrate obvious clinical benefit compared to control injection of normal saline. No long term evidence on outcomes was available and further conclusions were not warranted from the available data.

AUTHORS' CONCLUSIONS

A definitive conclusion cannot be drawn regarding the effectiveness of perianal injection of bulking agents for faecal incontinence due to the limited number of identified trials together with methodological weaknesses. Within the available data, however, we found no reliable evidence for effectiveness of one treatment over another in improving faecal incontinence. Larger well-designed trials with adequate numbers of subjects using reliable validated outcome measures are needed to allow definitive assessment of the treatment for both effectiveness and safety.