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

Efficacy of Caudal Block on Intra-operative Anal Sphincter Muscle Tone and Post-operative Analgesia During Anal Sphincter Sparing Procedures Under General Anaesthesia: A Randomized Control Trial

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.

Study Overview

• Status: Completed
• Conditions: Efficacy of Caudal Block on Intra-operative Anal Sphincter Muscle Tone
• Intervention / Treatment: Procedure: Caudal block; Drug: Morphine

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.

• Study Type: Interventional
• Enrollment (Actual): 26
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Egypt
  • CAiro, Egypt, 12566
    • Kasr Alainy medical school

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 58 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

- with complex anal fistula -

Exclusion Criteria:

• known hypersensitivity to amide type local anesthetics, contraindications to caudal block such as use of anticoagulant medication, local infection in the intervention site, increased intracranial pressure, severe aortic and / or mitral valve stenosis, and ischemic hypertrophic sub aortic stenosis, along with BMI (Body mass index) > 35 kg/m2 , anatomical abnormalities or previous surgeries involving the sacrum.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Triple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Control	Drug: Morphine; morphine to control pain and avoid using muscle relaxant
Experimental: Caudal	Procedure: Caudal block; caudal block with low dose bupivicaine 0.25% to preserve tone

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
The time to first request of rescue postoperative analgesic	the time interval between the end of surgery and the first request to postoperative morphine	in the first 24 hour

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Digital Rectal Examination Scoring System (DRESS	Digital Rectal Examination Scoring System to asses the anal tone	intraoperative

Collaborators and Investigators

• Sponsor: Kasr El Aini Hospital

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2021
• Primary Completion (Actual): December 1, 2021
• Study Completion (Actual): December 1, 2021

Study Registration Dates

• First Submitted: November 26, 2020
• First Submitted That Met QC Criteria: December 2, 2020
• First Posted (Actual): December 3, 2020

Study Record Updates

• Last Update Posted (Actual): October 20, 2022
• Last Update Submitted That Met QC Criteria: October 19, 2022
• Last Verified: October 1, 2022

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Analgesics; Sensory System Agents; Analgesics, Opioid; Narcotics; Morphine
• Other Study ID Numbers: N-33-2019

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: Undecided

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No