Long-term outcome of the use of botulinum toxin injection for functional anal pain

Optimal management of functional anorectal pain: a systematic review and network meta-analysis

Functional anorectal is idiopathic and characterised by severe and potentially intractable anorectal pain. The current review aims to appraise available evidence for the management of functional anorectal pain and synthesise reported outcomes using network meta-analysis. PubMed, CENTRAL and Web of Science databases were searched for studies investigating treatments for functional anorectal pain. The primary outcome was clinical improvement of symptoms and the secondary outcome was pain scores reported during follow-up. A Bayesian network meta-analysis of interventions was performed. A total of 1538 patients were included from 27 studies. Intramuscular injection of triamcinolone, sacral neuromodulation (SNM) and biofeedback were most likely to be associated with improvement in symptoms [SUCRA (triamcinolone) = 0.79; SUCRA (SNM) = 0.74; SUCRA (Biofeedback) = 0.61]. Electrogalvanic stimulation (EGS), injection of botulinum toxin A and topical glyceryl trinitrate (GTN) were less likely to produce clinical improvement [SUCRA (EGS) = 0.53; SUCRA (Botox) = 0.30; SUCRA (GTN) = 0.27]. SNM and biofeedback were associated with the largest reductions in pain scores [mean difference, range (SNM) = 4.6-8.2; (Biofeedback) = 4.6-6]. As biofeedback is noninvasive and may address underlying pathophysiology, it is a reasonable first-line choice in patients with high resting pressures or defecation symptoms. In patients with normal resting pressures, SNM or EGS are additional options. Although SNM is more likely to produce a meaningful response compared to EGS, EGS is noninvasive and has less morbidity. Whilst triamcinolone injection is associated with symptomatic clinical improvement, the magnitude of pain reduction is less.

Intravesical electromotive administration of botulinum toxin type A in improving the bladder and bowel functions: Evidence for novel mechanism of action

Objective: To examine the hypothesis that what is the concomitant mechanism of action botulinum toxin type A (BoNTA) administration by intravesical electromotive into the bladder resulting in bladder function improvement. We also tried to confirm the possibility of retrograde trans-axonal transportation of toxin.Design: Animal study.Setting: Ten male rabbits were divided into two groups.Participants: Group 1 (G1) (n = 5) (BoNTA/EMDA), and group 2 (G2) (n = 5) the control group.Interventions: Animals in G1received 10 IU/Kg of intravesical BoNTA through a specific catheter for electromotive drug administration (BoNTA/EMDA). About 0.1-0.15 ml of toxin was diluted in 1 ml of distilled water. The maximum frequency of the device for drug solution delivery was set at 4 mA for 15 min. In G2 as the control group, the same procedure was performed to deliver normal saline to the bladder.Outcome measures: Multiple biopsies were taken from bladder's contiguous structures one month postoperatively. The immunohistochemical (IHC) evaluation was performed with anti-clostridium botulinum toxoid type A mouse IgM monoclonal antibody.Results: In specimens of G1, BoNTA penetrated through muscular layers of the bladder wall and the staining was uniform in the urothelium, interstitium, and muscular layers. Positive IHC staining showed that BoNTA was traced in the upper and lower spinal cord in addition to pelvic nerve, sacral nerve plexus, intestine wall, and pelvic floor muscle. In G2, all the specimens were intact in IHC staining.Conclusions: The presence of BoNTA in lower and upper spinal cord suggests the possibility of retrograde trans-axonal transfer of toxin to lower and upper neural pathways which may result in simultaneous improvement in bladder and bowel functions.

The Role of Botox in Colorectal Disorders

PURPOSE OF REVIEW

To overview the current medical literature on the efficacy of botulism toxin treatment (BTX-A) for lower gastrointestinal disorders (GIT).

RECENT FINDINGS

BTX-A was found to have a short-term efficacy for the treatment of dyssynergic defecation. Surgical treatment was found to be more effective than BTX-A for the healing of chronic anal fissures, and BTX-A can be considered when surgery is undesirable. Data regarding the effects of BTX-A injection for the treatment of chronic anal pain is limited. Beneficial effects were observed only in a minority of patients. BTX-A treatment was found to be effective for the treatment of obstructive symptoms after surgery for Hirsprung's disease as well as for the treatment of internal anal sphincter achalasia. BTX-A treatment has a short-term efficacy and is safe. Further research is still needed in order to establish the exact place of BTX-A treatment of lower GIT disorders.

Botulinum toxins: mechanisms of action, antinociception and clinical applications

Botulinum toxin (BoNT) is a potent neurotoxin that is produced by the gram-positive, spore-forming, anaerobic bacterium, Clostridum botulinum. There are 7 known immunologically distinct serotypes of BoNT: types A, B, C1, D, E, F, and G. Clostridum neurotoxins are produced as a single inactive polypeptide chain of 150kDa, which is cleaved by tissue proteinases into an active di-chain molecule: a heavy chain (H) of ∼100 kDa and a light chain (L) of ∼50 kDa held together by a single disulfide bond. Each serotype demonstrates its own varied mechanisms of action and duration of effect. The heavy chain of each BoNT serotype binds to its specific neuronal ecto-acceptor, whereby, membrane translocation and endocytosis by intracellular synaptic vesicles occurs. The light chain acts to cleave SNAP-25, which inhibits synaptic exocytosis, and therefore, disables neural transmission. The action of BoNT to block the release of acetylcholine botulinum toxin at the neuromuscular junction is best understood, however, most experts acknowledge that this effect alone appears inadequate to explain the entirety of the neurotoxin's apparent analgesic activity. Consequently, scientific and clinical evidence has emerged that suggests multiple antinociceptive mechanisms for botulinum toxins in a variety of painful disorders, including: chronic musculoskeletal, neurological, pelvic, perineal, osteoarticular, and some headache conditions.