Bilateral versus unilateral botulinum toxin injections for chronic anal fissure: a randomised trial

BACKGROUND

Botulinum toxin injected into the internal anal sphincter is used in the treatment of chronic anal fissure but there is no standardised technique for its administration. This randomised single centre trial compares bilateral (either side of fissure) to unilateral injection.

METHODS

Participants were randomised to receive bilateral (50 + 50 units) or unilateral (100 units) Dysport® injections into the internal anal sphincter in an outpatient setting. Injection-related pain assessed by visual analogue scale was the primary outcome measure. Secondary outcomes were healing rate, fissure pain, incontinence, and global health scores.

RESULTS

Between October 2008 and April 2012, 100 patients with chronic anal fissure were randomised to receive bilateral or unilateral injections. Injection-related pain was comparable in both groups. There was no difference in healing rate. Initially, there was greater improvement in fissure pain in the bilateral group but at 1 year the unilateral group showed greater improvement. Cleveland Clinic Incontinence score was lower in the unilateral group in the early post-treatment period and global health assessment (EuroQol EQ-VAS) was higher in the unilateral group at 1 year.

CONCLUSIONS

Injection-related pain was similar in bilateral and unilateral injection groups. Unilateral injection was as effective as bilateral injections in healing and improving fissure pain without any deterioration in continence.

A double-blinded randomized multicentre study to investigate the effect of changes in stimulation parameters on sacral nerve stimulation for constipation

AIM

Sacral nerve stimulation (SNS) may be offered to patients with constipation who have failed to improve with conservative treatment. The response to SNS is variable, with a significant loss of efficacy in some patients. An increased frequency of stimulation may improve the efficacy of SNS for faecal incontinence. This study aimed to see if alteration of the pulse width or frequency improved the outcome for those with constipation.

METHOD

Eleven patients with constipation currently being treated by SNS were recruited from three centres. They were randomized to five different protocols of stimulation each applied for 5 weeks. Group 1 used standard settings (pulse width 210 μs, frequency 14 Hz); in the other four groups (Groups 2-5) the pulse width and/or frequency were halved or doubled. Patients and investigators were blinded to the group allocation.

RESULTS

The Cleveland Clinic constipation score varied significantly between the five groups. Group 1 achieved the lowest score mean (± SD) 13.4 (± 4.4) (P = 0.03). The number of digitations per defaecation was the lowest in Group 4, 90 μs and 14 Hz (P < 0.01). No other variable changed significantly. Standard settings were the most preferred by the recruited patients.

CONCLUSION

Alteration of pulse width or frequency of stimulation had no significant effect on the outcome of SNS for constipation.

A pilot study of chronic pudendal nerve stimulation for faecal incontinence for those who have failed sacral nerve stimulation

BACKGROUND

Sacral nerve stimulation (SNS) is used as a first-line treatment for faecal incontinence when conservative measures have failed. However, one-third of patients fail to benefit from this treatment. We hypothesised that sacral afferent stimulation can be maximised using pudendal nerve stimulation (PNS) and this may be of benefit in this patient group. The aim of this study was to assess chronic PNS for those who failed to improve with SNS.

METHODS

Ten patients who had failed SNS were recruited. All underwent percutaneous insertion of a stimulation lead with four-electrode array adjacent to the pudendal nerve. Continuous bipolar stimulation was administered using an external pulse generator over a 3-week period. Those who experienced a ≥50% reduction in the frequency of incontinent episodes over this period proceeded to chronic stimulation with an implantable pulse generator.

RESULTS

Five patients experienced a ≥50% reduction of incontinent episodes during test stimulation and proceeded to chronic stimulation. In these five patients, at a median (range) follow-up of 24 (6-36) months, the median (inter quartile range) frequency of incontinent episodes reduced from 5 (18.25) to 2.5 (3) per week (p = 0.043). Three patients maintained a ≥50% improvement in soiling. There was an improvement in the St Mark's continence Score from 19 (15-24) to 16 (13-19), p = 0.042. There were no significant changes in ability to defer defecation or in quality of life scores.

CONCLUSIONS

Pudendal nerve stimulation failed to improve the symptoms in the majority of patient who had failed SNS. Only a third experienced any improvement.

A pilot study to compare daily with twice weekly transcutaneous posterior tibial nerve stimulation for faecal incontinence

AIM

Posterior tibial nerve stimulation (PTNS) has been shown to improve faecal incontinence in the short term. The optimal treatment regimen is unclear with wide variations in protocol reported in the literature. The study aimed to assess two different regimens of transcutaneous PTNS and to establish whether increasing the frequency of stimulation increases the effectiveness.

METHOD

Thirty patients were randomized to receive once daily or twice weekly PTNS for a 6-week period. The treatment was carried out by the patient at home after instruction. The primary investigator was blinded to the patient allocation until the study had ended, at which point the symptoms were assessed. No further stimulation was given after 6 weeks and the patients were followed until their symptoms returned to the pre-stimulation state (baseline). The primary outcome measure was a change in the frequency of incontinent episodes.

RESULTS

Three patients in the daily group and none in the twice weekly group achieved complete continence. Only patients from the daily group showed a significant reduction in median (interquartile range) incontinent episodes per week from 5 (11.13) to 3.5 (4.31) (P = 0.025). There was no significant change in the frequency of defaecation nor in the ability to defer defaecation. Patients in the daily group experienced a significant improvement in the domains of lifestyle [2.2 (1.7) to 2.6 (1.65), P = 0.04] and embarrassment [1.7 (0.85) to 2.15 (0.4), P = 0.04] on the Rockwood Fecal Incontinence Quality of Life assessment. No adverse events were reported.

CONCLUSION

Transcutaneous PTNS can safely be used by the patient at home. Daily treatment may be more effective than twice weekly treatment. Larger studies are needed to investigate this further.

Sacral nerve stimulation: an effective treatment for chronic functional anal pain?

AIM

Chronic idiopathic anal pain is a common condition of unknown aetiology. Patients may have co-existing psychiatric disorders and existing treatments are often ineffective. A small number of published case reports suggest that sacral nerve stimulation (SNS) could treat this condition. This pilot study aimed to investigate the efficacy of SNS for the treatment of chronic anal pain.

METHOD

Ten patients with chronic idiopathic anal pain were recruited. All had failed to respond to conservative treatments. Clinical and psychological evaluation was performed in all patients prior to SNS. Temporary stimulation of the S3 foramina was performed for 3 weeks and outcome assessed by comparison of a pain score diary and visual analogue score obtained during stimulation and at baseline. Primary outcome was defined as a > 50% reduction in pain score.

RESULTS

Of the 10 patients recruited, five were found to have clinical depression. Four patients withdrew from the study prior to testing and six underwent peripheral nerve evaluation (PNE). Three patients had > 50% reduction in pain score and progressed to permanent SNS. Of these, only one had good pain control at latest follow-up of 5 years; the remaining two patients obtained no benefit and had their devices removed or deactivated. These two patients both had depression that was also not improved by SNS.

CONCLUSION

This study would suggest that SNS is not an effective treatment for chronic anal pain in the majority of patients. PNE is not an effective means of identifying which of these patients are likely to respond to permanent SNS.

A review of posterior tibial nerve stimulation for faecal incontinence

AIM

This review aimed to assess the published results of posterior tibial nerve stimulation (PTNS) for faecal incontinence.

METHOD

A search was performed of PubMed, MEDLINE and Embase to identify studies describing the clinical outcome of PTNS for faecal incontinence.

RESULTS

Thirteen studies were identified. These described the outcome of PTNS for faecal incontinence in 273 patients. Four described transcutaneous PTNS, eight percutaneous PTNS and one compared both methods of PTNS with a sham transcutaneous group. One investigated patients with faecal incontinence and spinal cord injury and another with inflammatory bowel disease. There was marked heterogeneity of the treatment regimens and of the end points used. All reported that PTNS improved faecal incontinence. A > 50% improvement was reported in episodes of faecal incontinence in 63-82% of patients. An improvement was seen in urgency (1-5 min). Improvement was also described in the Cleveland Clinic faecal incontinence score in eight studies. Patients with urge and mixed incontinence appear to benefit more than those with passive incontinence. Treatment regimens ranged in duration from 1-3 months. A residual therapeutic effect is seen after completion of treatment. Follow-up ranged from 1-30 months.

CONCLUSION

PTNS is effective for faecal incontinence. However, many of the published studies are of poor quality. Comparison between studies is difficult owing to differences in the outcome measures used, technique of PTNS and the timing and duration of treatment.

Randomized controlled trial of percutaneous versus transcutaneous posterior tibial nerve stimulation in faecal incontinence

BACKGROUND

Percutaneous, transcutaneous and sham transcutaneous posterior tibial nerve stimulation was compared in a prospective blinded randomized placebo-controlled trial.

METHODS

Patients who had failed conservative treatment for faecal incontinence were randomized to one of three groups: group 1, percutaneous; group 2, transcutaneous; group 3, sham transcutaneous. Patients in groups 1 and 2 received 30-min sessions of posterior tibial nerve stimulation twice weekly for 6 weeks. In group 3, transcutaneous electrodes were placed in position but no stimulation was delivered. Symptoms were measured at baseline and after 6 weeks using a bowel habit diary and St Mark's continence score. Response to treatment was defined as a reduction of at least 50 per cent in weekly episodes of faecal incontinence compared with baseline.

RESULTS

Thirty patients (28 women) were enrolled. Nine of 11 patients in group 1, five of 11 in group 2 and one of eight in group 3 had a reduction of at least 50 per cent in weekly episodes of faecal incontinence at the end of the 6-week study phase (P = 0·035). Patients undergoing percutaneous nerve stimulation had a greater reduction in the number of incontinence episodes and were able to defer defaecation for a longer interval than those undergoing transcutaneous and sham stimulation. These improvements were maintained over a 6-month follow-up period.

CONCLUSION

Posterior tibial nerve stimulation has short-term benefits in treating faecal incontinence. Percutaneous therapy appears to have superior efficacy to stimulation applied by the transcutaneous route.

REGISTRATION NUMBER

NCT00530933 (http://www.clinicaltrials.gov).

Sacral nerve stimulation for constipation

BACKGROUND

For over 10 years sacral nerve stimulation (SNS) has been used for patients with constipation resistant to conservative treatment. A review of the literature is presented.

METHODS

PubMed, MEDLINE and Embase databases were searched for studies demonstrating the use of SNS for the treatment of constipation.

RESULTS

Thirteen studies have been published describing the results of SNS for chronic constipation. Of these, three were in children and ten in adults. Test stimulation was successful in 42-100 per cent of patients. In those who proceeded to permanent SNS, up to 87 per cent showed an improvement in symptoms at a median follow-up of 28 months. The success of stimulation varied depending on the outcome measure being used. Symptom improvement correlated with improvement in quality of life and patient satisfaction scores.

CONCLUSION

SNS appears to be an effective treatment for constipation, but this needs to be confirmed in larger prospective studies with longer follow-up. Improved outcome measures need to be adopted given the multiple symptoms that constipation may be associated with. Comparison with other established surgical therapies also needs consideration.

A new minimally invasive technique for pudendal nerve stimulation

AIM

Pudendal nerve stimulation (PNS), which is an alternative to sacral nerve stimulation, requires neurophysiological confirmation of correct siting of the electrode. We describe a modification of the existing technique where placement is assisted by guidance to the ischial spine by a finger introduced per anum.

METHOD

Cadaveric dissection was carried out to confirm the accuracy of this new approach. The surface marking of the ischial spine is marked. A stimulating needle electrode inserted through a skin incision at this point, is advanced towards the ischial spine using a finger introduced per anum as a guide. Once effective stimulation of the pudendal nerve is confirmed by observed and palpated contraction of the anal musculature, a permanent stimulating electrode is inserted and the position confirmed by radiological screening.

RESULTS

Using cadaveric studies, the correct surface markings for needle placement were confirmed. This technique was then applied successfully for in vivo insertion of the needle electrode in 20 patients with bowel dysfunction, with only one lead displacement occurring over a mean follow-up period of 12 months.

CONCLUSION

Finger-guided assistance of PNS electrode insertion is simple and reproducible without requiring neurophysiological confirmation of nerve stimulation to ensure correct lead location.

Sacral nerve stimulation for faecal incontinence: results from a single centre over a 10-year period

AIM

Sacral nerve stimulation (SNS) is considered a first-line surgical treatment option for faecal incontinence. There is little information on long-term results. The results of SNS for faecal incontinence performed at a single centre over a 10-year period are reported.

METHOD

A cohort analysis of consecutive patients treated with SNS for faecal incontinence over a 10-year period was carried out. Data were collected prospectively using bowel habit diaries and St Mark's and Cleveland Clinic incontinence scores. Treatment success was defined as a >50% reduction in episodes of faecal incontinence compared with baseline.

RESULTS

Temporary SNS was performed in 118 patients, and 91 (77%) were considered suitable for chronic stimulation. The median period of follow up was 22 (1-138) months. Seventy patients were followed for 1 year with success in 63 (90%). Of 18 patients followed for 5 years, 15 (83%) reported continued success, 11 (61%) maintained full efficacy, 4 (22%) reported some loss, and 3 (17%) reported complete loss. Three patients with a 10-year follow up had no loss in efficacy. Overall, complete loss of efficacy was observed in 14 (16%) patients at a median of 11.5 months following implantation. A further 5 (6%) patients showed deterioration with time. In 9 (47%), no reason for the deterioration in symptoms could be identified.

CONCLUSIONS

SNS can be effective for up to 10 years. Some patients experience deterioration in symptoms over time. The reasons for this are often not evident.

Sacral nerve stimulation for faecal incontinence: patient selection, service provision and operative technique

AIM

Faecal incontinence is estimated to affect between 2 and 3% of Western adult populations. In recent years sacral nerve stimulation has become an important treatment modality, often as the first-line surgical therapy. The aim of this article was to review the current evidence regarding patient selection and surgical technique and to evaluate the logistics of providing a neurostimulation service.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of sacral nerve stimulation, neuromodulation, artificial pacemaker, faecal incontinence, patient selection, predictive factors and anal canal. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

Despite the success of sacral nerve stimulation for several pathophysiological causes of incontinence, case selection is of paramount importance. Sacral nerve stimulation should not be offered outside a multidisciplinary pelvic floor unit. Temporary evaluation using diary cards can lead to false positive and negative results. Adherence to a meticulous surgical technique, using low amplitude stimulation to guide lead placement, provides optimal clinical outcome.

CONCLUSION

The short-term outcome of sacral nerve stimulation is dependent on patient factors and operative technique. Despite this, specific preoperative predictive factors of treatment success have yet to be identified.

Sacral nerve stimulation for faecal incontinence: optimizing outcome and managing complications

AIM

A knowledge of the principles of neurostimulation is essential to achieve optimal efficacy and minimize adverse effects. The aim of this article was to review the current evidence regarding device programming in the management of patients having sacral nerve stimulation (SNS) for faecal incontinence.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of sacral nerve stimulation, neuromodulation, artificial pacemaker, faecal incontinence, programming, adverse effects and complications. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

Neurostimulator programming is an important component of SNS. Efficacy can be improved or restored with reprogramming. Adverse stimulation is often reversible, and nonstimulation-related complications are correctable. A total loss of efficacy can be explained in over one-half of patients.

CONCLUSION

An improved outcome of SNS can be achieved by selecting the best possible stimulation parameters individualized to each patient. Further research into the optimal settings is needed.

Future indications for sacral nerve stimulation

AIM

The aim of this article was to determine the effect of sacral nerve stimulation (SNS) on the treatment of faecal incontinence, constipation, irritable bowel syndrome, mixed urinary and bowel disorders, spinal injury and neurodegenerative disease, pain syndromes, and sexual dysfunction.

METHOD

A Medline search was performed including the keywords and/or MeSH headings of 'sacral nerve stimulation', 'neuromodulation', 'artificial pacemaker', 'faecal incontinence', 'constipation' and 'anal pain'. Further studies were identified by cross-referencing from relevant articles and by appraisal of recent peer-reviewed conference abstracts and proceedings.

RESULTS

SNS has been used for the treatment of urinary, bowel and sexual dysfunction, as well as pain resulting from such disorders, and dysfunction arising from nerve injury and degenerative disease. There is a paucity of high quality evidence to support the use of SNS for the majority of novel indications at present.

CONCLUSION

Good quality prospective, cross-over studies are required to determine the true benefits of SNS. Further research into patient selection, operative technique and stimulation parameters for existing indications will ensure a place for SNS in the future treatment algorithm of functional pelvic floor disorders.

Improving the efficacy of sacral nerve stimulation for faecal incontinence by alteration of stimulation parameters

Background

Sacral nerve stimulation (SNS) is an effective treatment for faecal incontinence, but only standard stimulation parameters have been used. This study assessed the clinical impact of altering the parameters.

Methods

Twelve patients with partially improved faecal incontinence following SNS underwent acute testing to select optimal stimulation parameters; rectal compliance was used as a surrogate marker. Parameters tested were: stimulation off; frequency 14 (standard), 31 or 6·9 Hz; and pulse duration 210 (standard), 450 or 90 µs. Patients completed a 2-week bowel diary, St Mark's continence score (SMCS) and Rockwood faecal incontinence quality-of-life (FIQL) score before testing using standard settings, and after testing using optimized settings.

Results

Optimal settings, determined by greatest increase in rectal compliance, were shorter pulse width in five patients and higher frequency in seven. Optimized stimulation resulted in a decrease in mean episodes of incontinence from 2·3 to 1·2 per week (P = 0·031), soiling from 3·3 to 1·7 days per week (P = 0·016), faecal urgency from 31 to 18 per cent of all evacuations (P = 0·055) and SMCS from 12·3 to 8·7 (P = 0·008); the FIQL coping/behaviour score improved (P = 0·008).

Conclusion

With a shorter pulse width and higher frequency, clinical efficacy in patients undergoing SNS for faecal incontinence can be improved.

Economic evaluation of sacral nerve stimulation for faecal incontinence

BACKGROUND

Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence in patients who have failed conservative management. This study established the cost-effectiveness of treating patients with SNS compared with non-surgical treatment.

METHODS

A decision analysis model was performed. Data from 70 patients were obtained from medical records, bowel habit diaries and Short Form 36 quality of life questionnaires. Direct medical and non-medical costs were ascertained using the 2005/2006 national tariff, national statistics, and medication, pad and device costs. Indirect non-medical costs were also estimated.

RESULTS

Incontinence episodes were reduced from a median of 12 per fortnight at baseline to one per fortnight with SNS. Based on direct medical and non-medical costs, the incremental cost-effectiveness ratio (ICER) for SNS was pound25 070 per QALY gained. It cost pound1038 more per year to treat patients with SNS for a median reduction of 286 incontinence episodes, equating to pound3.63 per episode reduced. When indirect non-medical costs were included the ICER was reduced to pound12 959 per QALY gained.

CONCLUSION

The ICER of pound25 070 is within the pound30 000 per QALY threshold recommended by the National Institute for Health and Clinical Excellence as an effective use of National Health Service resources with proper justification.

Predictive factors for successful sacral nerve stimulation in the treatment of faecal incontinence: a 10-year cohort analysis

OBJECTIVE

Sacral nerve stimulation (SNS) is an established treatment for faecal incontinence. We aimed to identify specific factors that could predict the outcome of temporary and permanent stimulation.

METHOD

A cohort analysis was performed to identify potential predictive factors in 81 patients who underwent temporary SNS at a single institution over a 10-year period (June 1996 to June 2006). Data were obtained from prospectively collected patient symptom diaries and quality of life questionnaires, operation reports, anorectal physiological studies, endoanal ultrasound images and radiology of lead placement.

RESULTS

Clinical outcome of temporary screening was not affected by patient gender, age, body mass index, severity or length of symptoms. The need for a repeated temporary procedure was associated with subsequent failure during screening (P = 0.008). A low threshold to obtain a motor response during temporary lead insertion was associated with improved outcome (P = 0.048). Evidence of anal sphincter trauma was associated with a greater risk of failure (P = 0.040). However, there was no difference in medium-term outcome between patients with external anal sphincter (EAS) defects and patients with intact anal sphincter muscles.

CONCLUSION

Variables have been identified that help to predict the outcome of SNS. The presence of an EAS defect should not preclude treatment.

Oxidation of 2-methoxynaphthalene by toluene, naphthalene and biphenyl dioxygenases:structure and absolute stereochemistry of metabolites

2-Methoxynaphthalene was subjected to biooxidation by whole cells of six organisms: Pseudomonas putida F39/D containing toluene dioxygenase, Escherichia coli JM109(pDTG601), containing recombinant toluene dioxygenase from Pp F39/D, Pseudomonas sp. NCIB 9816/11, containing naphthalene dioxygenase. E. coli JM109(pDTG141), containing recombinant naphthalene dioxygenase from NCIB 98161/11, E. coli C534(ProR/Sac) containing recombinant naphthalene dioxygenase from Pp G7, and Beijerinckia sp. B8/36, containing biphenyl dioxygenase. The major product of oxidation by the naphthalene and biphenyl dioxygenases has been isolated and identified as (1R,2S)-dihydroxy-7-methoxy-1,2-dihydronaphthalene, 2c. A minor product, (1R,2S)-dihydroxy-6-methoxy-1,2-dihydronaphthalene, 3c, has also been detected. Oxidation by the toluene dioxygenase-containing organisms led to the isolation of 3c as the major product. Minor products detected in these reactions were 2c, and a third compound, (1S,2S)-dihydroxy-3-methoxy-1,2-dihydronaphthalene, 4c. Structural studies and dehydration of the diols to a mixture of naphthols are described. The absolute stereochemistry of these new diols has been established by correlation with known compounds. The organisms' potential in the production of new metabolites as useful chiral synthons by biooxidation of 2-substituted naphthalenes is indicated.