Perioperative Analgesia With Ultrasound Guided Erector Spinae Block Versus Ultrasound Guided Caudal Block in Children
Phase: NA
Conditions: Local Analgesia Via Infiltration, Caudal Epidural Anesthesia, Caudal Block, Caudal Block for Postoperative Analgesia, Caudal Anesthesia, Erector Spinae Plane Block, Children
Sponsor: Alexandria University

Perioperative Analgesia With Ultrasound Guided Erector Spinae Plane Block Versus 
Ultrasound Guided Caudal Block In Children 
 
Study start date May 2024. Study completion date August 2024. 
Protocol Approved May 7th, 2024. Last edit and approval December 10th, 2024. 
Approved by the Ethics Committee of the Faculty of Medicine, member of ICLAS 
Number: 0108384.  
NCT Number: Not assigned yet. 
The study was conducted at El Shatby Pediatric Hospital, a university hospital 
affiliated with Alexandria University. 
Primary investigator:  
Rawan Hassan Mostafa Mahmoud Amer, MBBCh. 
Faculty of Medicine, Alexandria University, Alexandria, Egypt. 
Email: Rawan.hassan95@yahoo.com 
 
Study Supervisors: 
Prof. Dr. Ashraf Arafat Abdelhalim 
Professor of Anaesthesia and Surgical Intensive Care, Faculty of Medicine, Alexandria 
University. 
 
Prof. Dr. Ahmed Mohamed Ibrahim El Atar 
Professor of Anaesthesia and Surgical Intensive Care, Faculty of Medicine, Alexandria 
University. 
 
Dr. Aliaa Rabie Abdel Aziz 
Assistant Professor of Anaesthesia and Surgical Intensive Care, Faculty of Medicine, 
Alexandria University. 

 
 
INTRODUCTION 
Postoperative pain management in pediatric patients is a critical aspect of 
healthcare, demanding specialized attention due to the unique considerations of this 
vulnerable population. The challenge lies in addressing and recognizing pain 
effectively while minimizing potential side effects. (1-3) 
Moderate to severe unmanaged pain may lead to physiological or psychological 
distress. Physiologically, this unmanaged pain may trigger a cascade of stress 
responses that may affect a child’s overall health. Elevated stress hormones may lead 
to increased heart rate, blood pressure, and respiratory rate. Prolonged exposure may 
compromise the immune system, eventually delaying the healing process and 
increasing susceptibility to infections. (4) 
Psychologically, the effect of pain on paediatric patients is multifaceted and 
may contribute to emotional distress, anxiety, and fear, even leading to long-term 
behavioural changes. Negative association with healthcare settings, future surgeries 
or even simple medical procedures may be formed. Additionally, unmanaged pain 
may affect a child’s ability to concentrate, learn and engage in age-appropriate 
activities. (5-7) 
The evolving understanding of pain physiology in children has led to 
advancements in multimodal analgesic techniques. Pain management plans 
encompass a spectrum of interventions ranging from medications, psychological 
support, and regional anaesthesia. Caudal anaesthesia is one of the most commonly 
performed regional anaesthesia techniques in paediatrics. A single dose of bupivacaine 
in the epidural space when accessed through the sacral hiatus provides analgesia for 

almost the entirety of the surgical procedure time, but unfortunately, its action is time 
limited in the postoperative period. (8) 
An ultrasound guided technique has been proven to provide better accuracy and 
success rate along with decreased puncture rates and increased first puncture success 
rates compared to a blind caudal block. Transverse and longitudinal views using 
ultrasound illustrate the sacrococcygeal ligament, the two sacral cornua and the dura 
mater with epidural space. (9, 10)  
Erector spinae block is a relatively new technique first described by Forero et al 
in 2016. Since then, it has been described as an effective block in the paediatric 
population. It effectively blocks somatic and visceral pain when administered correctly 
in thoracic or abdominal surgeries, unilaterally or bilaterally. (11, 12) 
Its analgesic effect appears to be due to injecting local anaesthetic into the 
interfacial plane between the transversus process and erector spinae accompanied by 
diffusion into paravertebral and intercostal spaces, where it affects the ventral and 
dorsal rami of spinal nerves. (13, 14)  
As the field continues to progress, ongoing research and clinical innovations aim 
to provide an effective approach to the well-being of young surgical recipients with 
the most amount of pain control. In this study, we hypothesize that, erector spinae 
block may be an alternative technique for caudal block for perioperative analgesia in 
children undergoing lower abdominal surgeries. Our aim will be to compare between 
erector spinae block and the caudal block to determine which one will provide better 
postoperative analgesia for a longer duration with fewer side effects. 
 
 
 

AIM OF THE WORK 
Primary aim: is to evaluate the efficacy of postoperative pain management 
using the Face, Legs, Activity, Cry, Conceal ability (FLACC) Pain Scale.  
Secondary aim:  
• Intraoperative haemodynamic changes. 
• The time to first rescue analgesic. 
• Total postoperative analgesic requirements. 
•  Parent satisfaction with a 5-point Likert scale questionnaire. (15) 
• Number of patients required rescue analgesic postoperatively. 
• Time to Modified Aldrete score ≥9. (16) 
• PACU stay (min). 
• Incidence of any adverse effects.  
 
 

PATIENTS 
After approval of the Medical Ethics Committee of the Faculty of Medicine, 
Alexandria University. An informed written consent from every patient from 
parent/caregiver will be done in this study, the current study will be performed in El 
Shatby University Hospital for children on 60 patients who will be scheduled for 
elective lower abdominal surgeries under general anaesthesia.  
The minimum total hypothesized sample size of 60 eligible study participants 
will be needed to evaluate the efficacy of postoperative pain management using the 
Face, Legs, Activity, Cry, Consolabilitly (FLACC) Pain Scale. Taking into 
consideration an effect size of 20%, significance level of 5% and power of 8-% using 
Chi Square Test.  
This study will be a prospective randomized study. Randomization was done 
using a computer-generated random numbering of each study patient where even 
numbers will be group (ESB) and odd numbers will be group (CB). Opaque sealed 
envelopes will be used and will be opened in the operative theatre by an investigator 
who will be blinded to the study groups. The parents, children, surgeon, and the 
investigators who will collect the data after the block will be blinded to the study 
group. Patients will be randomized into two equal groups:  
Group (ESPB): patients will receive bilateral ultrasound guided erector spinae 
block of dilute solution at dose 0.4 ml/kg of 0.25% bupivacaine between the 10th 
transversus process and erector spinae muscle on each side, provided that it does not 
exceed toxic dose of bupivacaine 2.5 mg/kg. (17) 

Group (CB): patients will receive ultrasound guided caudal epidural block of 
dilute solution bupivacaine 0.25% at dose 1ml/kg, provided that it does not exceed 
toxic dose of bupivacaine 2.5 mg/kg. (18) 
 
 

Inclusion criteria: 
• Age between 2-7 years old. 
• ASA I-II. 
• Elective surgery under general anaesthesia. 
• Lower abdominal surgery. 
Exclusion criteria: 
• Parent/caregiver refusal. 
• Allergy to one of the study medications. 
• Renal or cardiac disease. 
• Infection or redness at the site of injection. 
• Clinically significant coagulopathy. 
• Spinal anomalies. 
• Altered mental status. 
• Developmental delay. 
• Additional surgery at different surgical sites. 
• Block failure. 
 

METHODS 
Preoperative evaluation 
1. All patients will be evaluated the day before surgery through proper history 
taking and clinical examination to exclude cardiovascular, respiratory, 
neurological, and metabolic diseases. 
2. Routine laboratory investigations including: 
• Complete blood count (CBC). 
• Bleeding time.  
• Clotting time.  
• Prothrombin activity & INR. 
• Random blood sugar. 
3. All parents will be informed about the techniques of both erector spinae and 
caudal blocks, and a written consent will be obtained from every parent. 
4. All children will not take any solid food for 6 hours preoperatively,  
but each will be allowed to drink clear fluids up to 2 hours before induction of 
anaesthesia.  
Anaesthetic Technique: 
• On arrival to operating theatre, all patients will be attached to a multichannel 
monitor to display continuous ECG monitoring, non-invasive BP monitoring and 
peripheral oxygen saturation (SpO2), nasopharyngeal temperature monitor using 
Draeger Monitor model Vista 120, Germany. 

• Inhalational induction will be conducted using incremental concentrations of 
sevoflurane up to 8% with 100% O2 (4 L/min) via face mask (Jackson-Rees 
modification of Ayer's T-piece).  
• After loss of consciousness, a 24G cannula will be inserted into a peripheral 
vein. 
• Laryngeal mask airway (LMA) that is appropriate size to age will be inserted, 
and anaesthesia will be maintained with oxygen and Isoflurane at double MAC 
delivered via Jackson-Rees circuit with pressure supported spontaneous 
ventilation (Trigger Sensitivity 0.7 L/min, PEEP 3, PS 10) using Penlon 
Ventilator (AV-S Model, Made in UK). 
• A diclofenac sodium suppository will be administrated in a dose of 1 mg/kg. 
• Bolus intravenous lactated ringers’ will be given at the dose of 10 ml/kg. 
• No intraoperative muscle relaxants, sedatives, or IV opioids will be 
administered. 
Block Procedure: 
All blocks will be given under ultrasound guidance (Philips ClearVue 350 made 
in USA) using a longitudinal parasagittal transducer probe (6–12 MHz) by the same 
experienced anaesthesiologist who will not participate in data collection, another 
anaesthetist will be called to the operating room after preparing the patient and block 
procedure so that, he will be blinded to group allocation.  
Group ESPB: 
Patients will be placed in lateral decubitus position. The area at the level of and 1-2 
cm lateral to T10 over both sides of spine will be sterilized with 10% povidone-iodine 
and the probe will be placed in sterile gloves. After visualization of the erector spinae 

muscle, the needle will be inserted proximally. After hydro dissection, the needle tip will 
be confirmed to be between the fascia of the erector spinae muscle group and the 
transverse process, the dilute solution of bupivacaine 0.25% at dose 0.4 ml/kg will be 
injected on each side. (16) After the block patients will be placed in supine position and 
surgery will take place 10 minutes after injection. 
Group CB: 
After induction of general anaesthesia, the patient will be placed in left lateral 
decubitus position with the upper hip flexed at 90-degree angle. The needle insertion 
site will be sterilized using 10% povidone-iodine and the probe will be covered with 
sterile gloves. The sacral hiatus will be visualized using the ultrasound as two 
hyperechoic band like lines, the superior line being the sacrococcygeal ligament and 
the inferior line the dorsum of the pelvic surface of the sacrum. A “pop” or “give” is 
usually felt when the sacrococcygeal ligament is penetrated. A 22G needle will be 
introduced at a 45° angle. Cautious aspiration will be performed to rule out an 
inadvertent systemic or spinal needle location then patients will receive dilute 
solution of bupivacaine 0.25% at dose 1 ml/kg between the two sacral cornua while 
observing caudal epidural space dilation or turbulent flow with Doppler. Then, we 
will wait 10 minutes before the first surgical incision. (18) 
Haemodynamic will be closely monitored. Failure of block will be defined as 
increase in heart rate and or mean arterial blood pressure (MAP) above 10% than 
baseline values at the beginning of surgery, intravenous fentanyl will be given at 
dose 0.5 ug/kg and patient will be excluded from the study and replaced by another 
patient. Methods to keep normothermia will be done via warmed iv fluids and forced 
air-warming blankets. 

At the end of surgery, O2 100% > 5 L/min will be continued after the 
discontinuation of sevoflurane. Once the patient shows adequate recovery from 
anaesthesia, oropharyngeal suction will be performed, and the LMA will be 
removed. Patients will be transferred to the post anaesthesia care unit (PACU) for 
monitoring of vital signs. Children will be considered ready for discharge from the 
PACU when being fully awake, stable vital signs for 30 min, no pain, no nausea or 
vomiting and the Modified Aldrete post-anesthesia score was ≥9.  
MEASUREMENTS 
The following parameters will be measured:  
1.  Demographic data: 
➢ Age. 
➢ Sex. 
➢ Weight. 
➢ Duration of surgery: (time from the start of induction till discontinuation of 
the inhaled anaesthetics in minutes).  
➢ Duration of anaesthesia: (from skin incision to final skin sutures in 
minutes). 
➢ Type of surgical procedure. 
2.  Haemodynamic measurements: 
➢ Heart rate (beats/min) using lead ΙΙ electrocardiogram (ECG) waves. 
➢ Mean arterial blood pressure: (MABP) in mmHg. 
➢ Oxygen saturation. 
They will be monitored and recorded at the following times: 

• Pre-induction. 
• Post-induction. 
• Immediately after performing the block. 
• At the start of surgical manipulation. 
• Intraoperative every 10 minutes. 
• At the end of the operation. 
 
 

3. Time to Modified Aldrete score ≥ 9. 
4. PACU stay (min). 
5. Postoperative pain: It will be assessed 15, 30 minutes in recovery room then 
every 2 hours the next 8 hours using FLACC Behavioural Pain Assessment 
Scale. Postoperative pain score will be assessed by a nurse blinded to the patient's 
anaesthetic management.(19) 
FLACC Behavioural Pain Assessment Scale 5 parameters: Table (1) 
1. Face. 
2. Legs. 
3. Activity. 
4. Cry. 
5. Consolability. 
Table (1): FLACC Behavioural Pain Assessment Scale 
Category 
0 score 
1 score 
2 score 
Face 
No Particular 
expression or smile 
Occasional grimace or 
frown; withdrawn, 
disinterested 
Frequent to constant 
frown, clenched jaw, 
quivering chin 
Legs 
Normal position  
or relaxed 
Uneasy, restless, tense 
Kicking or legs  
drawn up 
Activity 
Lying quietly, normal 
position, moves easily 
Squirming, shifting 
back and forth, tense 
Arched, rigid, or 
jerking 
Cry 
No cry (awake or 
asleep) 
Moans or whimpers, 
occasional complaint 
Crying steadily, 
screams or sobs; 
frequent complaints 
Consolability 
Content, relaxed 
Reassured by 
occasional touching, 
hugging, or being 
talked to; distractible 
Difficult to console  
or comfort 

 
 
 

Interpreting the Behavioural Score: Table (2) 
Each category is scored on the 0–2 scale, which results in a total score of 0–10. 
Table (2): Interpreting the FLACC Behavioural Score 
0 
Relaxed and comfortable 
1–3 
Mild Pain 
4–6 
Moderate pain 
7–10 
Severe Pain  
 
6.  Time to first postoperative analgesic request 
The time elapsed between end of surgery and first administration of an 
analgesic.  
A postoperative pain score of ≥ 4 will be managed with paracetamol 10 mg/kg 
intravenous then will be repeated every 6 hours as required. 
If pain persists after dose of paracetamol or score >4, nalbuphine will be given 
at dose 0.1 mg/kg intravenously. 
7.  Total postoperative analgesics requirement will be recorded. 
8.  Number of patients who will require postoperative rescue analgesia. 
9.  Parent satisfaction:  
Parent satisfaction with a 5-point Likert scale questionnaire. 
10. Side effects: 
A) Side effects related to bupivacaine:  

• CNS: Nausea, vomiting, circumoral numbness, facial tingling, vertigo, 
tinnitus, restlessness, anxiety, dizziness, seizure, coma. 
• Cardiovascular: hypotension, arrhythmia, bradycardia, heart block, 
cardiac arrest. 
• Allergic reactions 
B) Side effects related to the erector spinae technique: 
In addition to the common complications associated with any peripheral 
nerve block (local anaesthetic toxicity, intravascular injection, nerve injury, 
bleeding, and infection), vascular puncture, pleural puncture, pneumothorax, 
and failed block are the primary complications. 
C) Side effects related to the caudal block technique:  
Epidural abscess, meningitis, post dural puncture headache, subdural 
injection, pneumocephalus, air embolism and back pain. 
 
 
 

ETHICS OF RESEARCH 
Research on human or human products: 
 
Prospective study: Informed consent will be taken from patients. In case of 
incompetent patients, the informed consent will be taken from the guardians. 
 
Retrospective study: Confidentiality of records will be considered. 
 
DNA / genomic material: Informed consent for DNA / genomic test and for 
research will be taken from patients. No further tests will be carried out except 
with further approval of committee and patients. If the samples will travel 
outside Egypt the researcher will be responsible for transportation and security 
approval. 
 
All drugs used in the research are approved by the Egyptian Ministry of Health. 
 
Research on animal: 
 
The animal species are appropriate for the test. 
 
After test, if the animal will suffer, it will be euthanized and properly disposed. 
 
After operation, it will have a proper postoperative care. 
 
 
 
 
 

RESULTS 
All results obtained will be assessed, tabulated, and statistically analysed 
according to established statistical methods. 
 
 

DISCUSSION 
The results obtained from this study will be discussed in view of achievement 
of the aim and compared with any available published data in the same field of 
research. 
 
 

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