Recruiting

SZMN Block

Sponsor:

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Code:

NCT07176533

Conditions

Tonsillitis

Eligibility Criteria

Sex: All

Age: 3 - 9

Healthy Volunteers: Not accepted

Interventions

Suprazygomatic maxillary nerve block (SZMN) with bupivacaine

Suprazygomatic maxillary nerve block (SZMN) with placebo

Study Details

Brief summary:

Tonsillectomies are among the most common surgical procedures performed in pediatric populations, with more than 14,000 procedures performed annually in Ontario, with more than 80% being performed to treat sleep-disordered breathing, including sleep apnea. Despite being a routine procedure, postoperative pain is a prevalent challenge following tonsillectomies, with significant pain lasting 7 to 10 days and peaking within the first 3 days following surgery. Effective pain management is critical not only to enhance patient comfort, but to ensure functional recovery, decrease the risk of post-surgical complications, and reduce the risk of hospital readmissions. The suprazygomatic maxillary nerve block (SZMN block) has become a promising alternative to opioids for the management of post-tonsillectomy pain. The SZMN block numbs the nerves in the facial region that would contribute to feeling pain following tonsillectomy. Although the SZMN block has been successful in adult tonsillectomies and pediatric cleft palate repairs, its success in pediatric tonsillectomies remains under investigation. This randomized controlled trial aims to evaluate the efficacy and safety of the SZMN block in pediatric tonsillectomy and adenotonsillectomy patients, through its role in providing pain management over 14 days following surgery. This study will be conducted at Victoria Hospital, London Health Sciences Centre.

Conditions

Tonsillitis

Study ID

NCT07176533

Start date

Jan 1, 2026

Status verified date

Sep, 2026

Completion date

Jan 1, 2028

Anticipated

Primary completion date

Jun 30, 2027

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 3 - 9

Healthy Volunteers: Not accepted

Inclusion Criteria:

1. Patients undergoing coblation intracapsular tonsillectomy or adenotonsillectomy for sleep apnoea.
2. Between 3-9 years old (inclusive).
3. Patient(s) and guardian(s) can consent to participate in the study.
4. Legal guardian(s) can read and write in English.

Exclusion Criteria:

1. Patient or legal guardian refusal to participate in the study.
2. Emergency surgery.
3. Allergies to local anesthetics.
4. Patients with coagulopathy.
5. Congenital facial abnormalities including (but not limited to) hemifacial microsomia, maxillary hypoplasia, Treacher-Collins syndrome, and Goldenhar syndrome.
6. Developmental delay or neurological impairment including (but not limited to) Trisomy 21, cerebral palsy, and autism spectrum disorder.
7. Previous airway surgery or a known or predicted airway difficulty.

Study Design

Enrollment

60 participants

Anticipated

Allocation

Randomized

Intervention Model

Parallel Assignment

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Suprazygomatic maxillary nerve block (SZMN) with bupivacaine

Participants will receive 15 mg/kg of Tylenol and 6 mg/kg of celecoxib (a nonsteroidal anti-inflammatory (NSAID drug) up to a maximum dose of 200 mg prior to the start of general anesthesia which will consist of gas or intravenous induction (2 mcg/kg fentanyl, 0.5 mg/kg dexamethasone). The SZMN block will be performed using 0.2 ml/kg bilaterally of 0.25% bupivacaine (MARCAINE) (cumulative dose 0.4 ml/kg) (local anesthetic), up to a maximum dose of 5 mL per side. The surgery (tonsillectomy or adenotonsillectomy) will then proceed according to standard of care practices.

placebo comparator: Suprazygomatic maxillary nerve block (SZMN) with placebo

Participants will receive 15 mg/kg of Tylenol and 6 mg/kg of celecoxib (a nonsteroidal anti-inflammatory (NSAID drug) up to a maximum dose of 200 mg prior to the start of general anesthesia. which will consist of gas or intravenous induction (2 mcg/kg fentanyl, 0.5 mg/kg dexamethasone). The SZMN block will be performed using 0.2 ml/kg of saline (placebo) up to a maximum dose of 5 mL per side. The surgery (tonsillectomy or adenotonsillectomy) will then proceed according to standard of care practices.

Interventions

Suprazygomatic maxillary nerve block (SZMN) with bupivacaine

Participants will receive 15 mg/kg of Tylenol and 6 mg/kg of celecoxib (a nonsteroidal anti-inflammatory (NSAID drug) up to a maximum dose of 200 mg prior to the start of general anesthesia which will consist of gas or intravenous induction (2 mcg/kg fentanyl, 0.5 mg/kg dexamethasone). The SZMN block will be performed using 0.2 ml/kg bilaterally of 0.25% bupivacaine (MARCAINE) (cumulative dose 0.4 ml/kg) (local anesthetic), up to a maximum dose of 5 mL per side. . The surgery (tonsillectomy or adenotonsillectomy) will then proceed according to standard of care practices.

Suprazygomatic maxillary nerve block (SZMN) with placebo

Participants will receive 15 mg/kg of Tylenol and 6 mg/kg of celecoxib (a nonsteroidal anti-inflammatory (NSAID drug) up to a maximum dose of 200 mg prior to the start of general anesthesia. which will consist of gas or intravenous induction (2 mcg/kg fentanyl, 0.5 mg/kg dexamethasone). The SZMN block will be performed using 0.2 ml/kg of saline (placebo) up to a maximum dose of 5 mL per side. The surgery (tonsillectomy or adenotonsillectomy) will then proceed according to standard of care practices.

Primary outcome measure

  • Impact of the suprazygomatic maxillary (SZMN) nerve block on opioid consumption in IV morphine equivalents in post-anesthesia care unit (PACU). [ Time Frame: 0-24 hours following surgery ]

Central Contacts and Locations

Central contacts

Abhijit Biswas

5196858500abhjit.biswas@lhsc.on.ca

Locations

Victoria Hospital, London Health Sciences Center, Western University

Recruiting

London, Ontario, Canada, N6A5W9

Contacts

Abhijit Biswas, FRCPC

+14168301696abhijit.biswas@lhsc.on.ca

More Information

Sponsor

London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's

Last update posted

Sep 22, 2026

Last verified

Sep, 2026

Keywords

  • Pain control
  • Tonsillectomy
  • Adenotonsillectomy
  • Suprazygomatic maxillary nerve block
  • Anesthesia

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-24. This information was provided to ClinicalTrials.gov by London Health Sciences Centre Research Institute OR Lawson Research Institute of St. Joseph's on 2026-09-22. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.