Efficacy of Caudal Block on Intra-operative Anal Sphincter Muscle Tone and Post-operative Analgesia During Anal Sphincter Sparing Procedures Under General Anaesthesia
Condition: Efficacy of Caudal Block on Intra-operative Anal Sphincter Muscle Tone
Study type: Interventional

Summary: 
      upplementing general anaesthesia with caudal analgesia in sphincter sparing procedures might
      be useful as it will provide a satisfactory combination of sphincter muscle tone
      preservation, good intraoperative and postoperative analgesia along with a reduction in the
      consumption of opioids and anaesthetic drugs. To the best of our knowledge, this anaesthetic
      technique was not tested in sphincter sparing procedures before.
    

Detailed description: 
      Anal fistulae, defined as an abnormal connection between the distal alimentary tract and the
      integument, are among the common illnesses affecting the anal canal, with a prevalence rate
      of 8.6 cases per 100,000.1 Usually, anorectal fistulae are safely and reliably treated by
      fistulotomy. One of the common complications of fistulotomy is incontinence due to sphincter
      injury, with an incidence reaching up to 12%2. Moreover, this technique is not well suited
      for complex anal fistulae due to the prevalent risk of incontinence reaching up to 50%2. That
      created the need for sphincter sparing procedures to evolve which do not involve division of
      any portion of the sphincter complex, thus evolvement of an anaesthetic technique which
      spares the presence of muscle tone, and provides good postoperative analgesia.2,3 The choice
      of anaesthetic technique for sphincter sparing procedures is challenging. Regional
      anaesthetic techniques such as saddle, lumbar epidural, and caudal blocks are considered well
      tolerable and reliable for anorectal surgery. Lumbar epidural local anaesthesia does not
      produce a uniform anaesthetic effect across the spinal segments as the large size of the L5
      and S1 nerve roots may be resistant to the local anaesthetic effect and The cranial spread of
      lumbar epidural anaesthesia is somewhat more extensive than the caudal spread which suggest
      that the onset of the block of the caudal sacral segments may be later than that of the
      lumbar segments. 4On the other hand, saddle anaesthesia is the preferred route for most of
      the anorectal surgeries as it abolishes the muscle tone5; however, loss of the muscle tone
      consequently increases the possibility of the external anal sphincter injury in complex anal
      fistulas. Thus; sphincter sparing procedures are usually performed under general anaesthesia
      omitting neuromuscular blocking agents in order to preserve sphincter tone intraoperatively.6
      However, the choice of general anaesthesia for this procedure still lacks adequate
      postoperative analgesic plan.

      Caudal block is not a commonly used route for analgesia in adults due to the evolution of
      lumbar epidural block5. The introduction of ultrasound for guiding different blocks,
      including caudal block had increased the use of caudal block7 especially when sacral nerve
      spread of anaesthetics is preferred over lumbar nerve spread8. Modern epidural dosing
      regimens (e.g. 0.0625% to 0.1 % bupivacaine with 2-4 mcg/ml fentanyl) 6,9 reduce the total
      local anaesthetic dose required and motor block experienced; potentially allowing the patient
      to be ambulatory.

      Therefore, Supplementing general anaesthesia with caudal analgesia in sphincter sparing
      procedures might be useful as it will provide a satisfactory combination of sphincter muscle
      tone preservation, good intraoperative and postoperative analgesia along with a reduction in
      the consumption of opioids and anaesthetic drugs. To the best of our knowledge, this
      anaesthetic technique was not tested in sphincter sparing procedures before.
    

Intervention name(s): Caudal block; Morphine
Intervention type(s): Procedure; Drug
Intervention description(s): caudal block with low dose bupivicaine 0.25% to preserve tone; morphine to control pain and avoid using muscle relaxant
Intervention MeSH terms: Morphine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Care Provider, Outcomes Assessor)
Primary purpose: Supportive Care