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21/534 Surgical management of successfully reduced incarcerated inguinal hernia in children



The aim of the Health Technology Assessment (HTA) Programme is to ensure that high quality research information on the clinical effectiveness, cost-effectiveness and broader impact of healthcare treatments and tests are produced in the most efficient way for those who plan, provide or receive care from NHS and social care services. The commissioned workstream invites applications in response to calls for research on specific questions which have been identified and prioritised for their importance to the NHS, patients and social care.

Research question

What is the comparative effectiveness of different timings for surgery to repair a successfully reduced incarcerated inguinal hernia in children?

  1. Intervention: Emergency versus elective surgical repair of a successfully reduced incarcerated inguinal hernia. Applicants to define and justify ‘emergency’ and ‘elective’ and type of surgery.
  2. Patient group: Infants, children and/or young people, stratified by age (applicants to define and justify) with a recently incarcerated inguinal hernia that has been successfully reduced. Applications are encouraged which include recruitment from geographic populations with high disease burden which have been historically underserved by research activity in this field.
  3. Setting: Secondary care.
  4. Comparators: Interventions will be compared against each other.
  5. Study design: A randomised controlled trial with an internal pilot phase to test key trial processes such as recruitment and adherence. Clear stop/go criteria should be provided to inform progression from pilot to full trial.
  6. Important outcomes: Recurrence of hernia; ischemic complications; pain; anaesthetic complications; parent and carer/patient acceptability; health care utilisation. Existing Core Outcomes should be included amongst the list of outcomes unless a good rationale is provided to do otherwise.
  7. Other outcomes: Scrotal oedema; testicular/ovarian atrophy; surgical site infection; need for surgery before planned surgery; length of hospital stay; return to usual activities.
  8. Minimum duration of follow-up: 12 months. Longer-term follow up: If appropriate, researchers should consider obtaining consent to allow potential future follow up through efficient means (such as routine data) as part of a separately funded study.


An inguinal hernia occurs when a part of the bowel, such as the intestine, pushes through a weak spot in the muscles of the abdominal wall into an area called the inguinal canal. They can occur at any age, but are most common during infancy and childhood, and 80-90% of them happen in boys. Inguinal hernias are often asymptomatic and may appear when the child is straining and disappear when they are relaxed.

Inguinal hernias are at risk of becoming incarcerated. This is when the protruding part of the bowel does not return through the abdominal wall when the child is relaxed. Incarcerated hernias cause the child pain and are at risk of strangulation – this is when the blood supply to the part of the intestine outside of the abdominal wall is cut off. Strangulation is a medical emergency because it could lead to sepsis. Therefore, incarcerated inguinal hernias need to be treated promptly to prevent the risk of strangulation. Most incarcerated inguinal hernias can be successfully reduced (pushed back into place) non-operatively but an operation is then needed to repair the hole in the abdominal wall.

There is uncertainty about the timing of surgery: children with a reduced inguinal hernia are at high risk of incarceration again and the associated risk of needing emergency surgery due to strangulation. Also, hernias in infants and young children are more likely to contain part of the bowel rather than fat, as they have less intra-abdominal fat than young people and adults. These concerns suggest the need for earlier surgery. However, newborns and young infants have a higher risk of severe critical events due to general anaesthesia, so it may be better to delay surgery.

As such, the British Association of Paediatric Surgeons recently highlighted this research question regarding the optimal timing of successfully reduced inguinal hernia as one of their highest research priorities, the results of which would help inform future practice. We expect applicants to demonstrate how they will establish the size of the potential population as part of their internal pilot. Applications should be co-produced, demonstrating an equal partnership with service commissioners, providers and service users (or their advocates) in order to provide evidence and actionable findings of immediate utility to decision-makers and service users. Applicants may wish to consult the NIHR INVOLVE guidance on co-producing research.

Additional commissioning brief background information

A background document is available that provides further information to support applicants for this call. It is intended to summarise what prompted the call and the existing evidence base, including relevant work from the HTA and wider NIHR research portfolio. It was researched and written on the basis of information from a search of relevant sources and databases, and in consultation with a number of experts in the field. If you would like a copy please email

Making an application

If you wish to submit a Stage 1 application for this call, the online application form can be found on the Funding opportunities page.  To select this call, use the filters on the right of the screen or search using the call name and/or number.

Your application must be submitted on-line no later than 1pm on the 1 December 2021. Applications will be considered by the HTA Funding Committee at its meeting in January 2022.

Guidance notes and supporting information for HTA Programme applications are available by clicking the links.

Important: Shortlisted Stage 1 applicants will be given eight weeks to submit a Stage 2 application. The Stage 2 application will be considered at the Funding Committee in May 2022.

Applications received electronically after 1300 hours on the due date will not be considered.

For commissioned topics, the Programme strongly discourages the practice of the same co-applicant joining more than one competing team. There may be unusual circumstances where the same person could be included on more than on application eg a lead from a named charity or a unique national expert in a condition. For such exceptions (i) each application needs to state the case as to why the same person is included (ii) the shared co-applicant should not divulge application details between teams and (iii) both teams should acknowledge in their application that they are aware that one of their co-applicants is part of a competing application and that study details have not been shared. 

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