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

Haemorrhoids present often to primary and secondary care, and haemorrhoidal procedures are among the most common carried out. They may co-exist with more serious pathology, and correct evaluation is important. In most cases a one-off colonoscopy in patients aged 50 or above with flexible sigmoidoscopy in younger patients is reasonable. Many people with haemorrhoids do not require treatment. Topical remedies provide no more than symptomatic relief-and even evidence for this is poor. Bulk laxatives alone may improve symptoms of both bleeding and prolapse and seem as effective as injection sclerotherapy. Rubber band ligation is effective in 75% of patients in the short term, but does not treat prolapsed haemorrhoids or those with a significant external component. Conventional haemorrhoidectomy remains the most effective treatment in the long term, the main limitation being post-operative pain. Metronidazole, topical sphincter relaxants and operative technique have all been shown to reduce pain. Stapled haemorrhoidectomy and haemorrhoidal artery ligation techniques are probably less effective but less painful. Long-term data are poor for all procedures, with many studies reporting only 1-3 years of follow-up data. Haemorrhoids are common in pregnancy, occurring in 40% of women. They can usually be treated conservatively during pregnancy, with any treatment delayed until after delivery. Acutely strangulated haemorrhoids may be treated either conservatively or operatively. There is an increased risk of anal stenosis after acute surgery, but the risks of sepsis and sphincter damage are less significant than previously thought. The majority of patients who are treated conservatively will still require definitive treatment at a later date.

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.

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.

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.