Efficacy of Probiotic Gargles in Reducing Post-operative Complications in Adult Post-tonsillectomy Patients: a Study Protocol for a Pilot Double-blinded, Randomised Controlled Trial and Feasibility Study
Authors: Nasserallah Michael , Silva Nalaka de , Tobin Vicky , Rozen Warren , Hunter-Smith David 
Published: April 2021

Abstract
Background: Tonsillectomy is one of the most commonly performed otolaryngologic procedures on children and adults. Despite improvements in surgical techniques, postoperative morbidity remains a significant clinical problem. Postoperative pain is the most common and incapacitating symptom that patients experience universally following tonsillectomy. For many years it has been suggested that post-tonsillectomy pain is further worsened by colonisation of tonsillar fossae with organisms that induce an inflammatory response, thereby making pain worse. However, antibiotic treatment was not found to result in a clinically significant reduction in pain or postoperative analgesic requirements according to the most recent Cochrane review published in 2012. Probiotics have shown to reduce inflammatory pain and improve functional abdominal pain in conditions such as irritable bowel syndrome. There are also several studies demonstrating that probiotics reduce recurrent pharyngotonsillitis, otitis media and other upper respiratory tract infections. The use of probiotics to manage post tonsillectomy pain is a novel idea that has not yet been investigated and may demonstrate promising results.Aim: The aim of this pilot study is to determine the feasibility of a 14-day postoperative course of probiotic (Streptococcus salivarius K12) gargles compared to placebo gargles on morbidity following adenotonsillectomy in adults.Design: This study is a double-blinded, randomised, placebo-controlled feasibility trial. The participants that will be recruited to this study are from the ENT waiting list at a single outer metropolitan hospital located in Melbourne, Australia. Methods: Thirty adults, aged 18-55 years, all scheduled for elective tonsillectomy with or without adenoidectomy, will be included and assigned to receive either probiotic (S. salivarius K12) gargles or placebo (isomalt) gargles for 14 days after surgery. The primary outcomes are postoperative pain and requirement of opiate analgesia. Secondary outcomes are assessing the safety and tolerability of probiotics and the feasibility of the trial. Study design will be assessed by any changes (during the pilot or recommended) to the protocol, recruitment by the numbers screened and time to enrol 30 participants; randomisation by the similarity of characteristics in groups at baseline, adherence will be assessed by the amount of probiotic/placebo gargle consumed, attendance to follow up appointments and completion of daily questionnaires; safety by will be examined by the number and description of adverse events and retention by the numbers withdrawn.Discussion: This study will provide preliminary results that may support the feasibility of a large scale RCT to test the benefits of probiotic gargles post (adeno)tonsillectomy. Trial registration: ACTRN 12619001474145; retrospectively registered 24/10/2019; First participant enrolled 14/10/2019; Australian and New Zealand Clinical Trial Registry