Ultrasound Guided Local Anesthetic Field Block (A Five Step Procedure) for Open Inguinal Hernia Repair
Condition: Inguinal Hernia
MeSH terms: Hernia; Hernia, Inguinal
Study type: Interventional

Summary: 
      The aim of this study is to evaluate success, efficacy, feasibility and safety of a simple
      five step ultrasound guided local anesthetic infiltration technique for unilateral open
      inguinal hernia repair and to determine the non-inferiority of the block to spinal anesthesia
      by comparing intraoperative and postoperative complications, pain control and patient and
      surgeon satisfaction of the block with spinal anesthesia.
    

Detailed description: 
      Open Inguinal hernia repair is one of the commonest procedures performed worldwide. Still,
      there is no consensus regarding the optimum anesthesia technique for this surgery. General,
      spinal, epidural and local anesthesia techniques have all been used, each having its own
      advantages and disadvantages.

      General anesthesia carries risks of possible airway complications, postoperative
      deterioration of cognitive function, sore throat, nausea, vomiting and prolonged period of
      immobilization with associated risk of deep vein thrombosis and longer hospital stay. Spinal
      anesthesia, although effective, is not without risk in patients with decompensated heart
      disease, recent head injury, convulsions and coagulopathies. Also spinal and epidural
      anesthesia have been associated with hemodynamic instability, vomiting, urinary retention,
      post-dural puncture headache, and backache.

      Use of pre-incision infiltration of local anesthetics for field blocks has been found to be
      an effective adjunct as well as an alternative to spinal and general anesthesia in many
      studies. Combined with sedation or on its own, it offers less cardiovascular instability,
      early ambulation and effective post-operative pain control. Also, it has been found to reduce
      hospital costs by 50% and gives better patient satisfaction.

      Harvey Cushing and William Halsted first described the inguinal field block in 1900. since
      then, its efficacy and advantages have been compared by many surgeons and anesthesiologists
      in a number of studies. Refinements and modifications in the technique still continue. In
      1963, Joseph L Ponka described in great detail a seven step procedure of performing it in 837
      patients successfully.

      In 1994, Parvis and colleagues did a step by step technique for local anesthetic infiltration
      field block for open inguinal hernia repair.

      Ultrasonography is a safe and effective form of imaging. Over the past two decades,
      ultrasound equipment has become more compact, of higher quality and less expensive.
      Ultrasounds have been used to guide needle insertion and a number of approaches to nerves and
      plexuses have been reported. A clear advantage of the technique is that ultrasound produces
      "living pictures" or "real-time" images. The identification of neuronal and adjacent
      anatomical structures (blood vessels, peritoneum, bone, organs) along with the needle is
      another advantage. Moreover, anatomical variability may be responsible for block failures,
      and ultrasound technology enabling direct visualization may overcome this problem.
      Sonographic visualization allows for the performance of extra-epineurial needle tip
      positioning and administration of local anesthetic avoiding intra-epineurial injection.

      A modification to the technique performed by Parvis and colleagues will be tested in this
      study. Our modification will be performing the technique under ultrasound guidance and
      completely before skin incision, which, to the best of our knowledge, was not attempted in
      the literature before.

      Local anesthesia administered before skin incision produces longer postoperative analgesia
      because local infiltration theoretically inhibits the build-up of local nociceptive molecules
      and, therefore, there is better pain control in the postoperative period.This study aims at
      evaluating success, efficacy, feasibility and safety of a simple five step ultrasound guided
      local anesthetic infiltration technique for unilateral open inguinal hernia repair and also
      to compare intraoperative and postoperative complications and pain control of the block with
      spinal anesthesia.
    

Intervention name(s): US guided five step field block; Spinal anesthesia
Intervention type(s): Procedure; Procedure
Intervention description(s): Ultrasound will guide needle insertion in the following layers (except intradermic injection):
Subdermic infiltration. Approximately 8 milliliters
Intradermic injection (making of the skin wheal). of approximately 6 milliliters.
Deep subcutaneous injection. 8 milliliters of the mixture will be injected deep into the subcutaneous adipose
Subfascial infiltration. Approximately eight milliliters of the anesthetic mixture will be injected immediately underneath the aponeurosis of the external oblique.
Pubic tubercle and hernia sac injection. Occasionally, infiltration of ten milliliters of the mixture at the level of the pubic tubercle, around the neck and inside the indirect hernia sac; Spinal anesthesia will be administered in sitting position, with 25 gauge Quincke spinal needle in L3-L4 intervertebral space, under all aseptic precautions and local infiltration, with 3.0 ml of 0.5% bupivacaine (heavy) after ensuring free, clear and adequate flow of cerebrospinal fluid. After giving spinal anesthesia, patient will be made to lie supine.
Intervention MeSH terms: Anesthetics
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: A Randomized Controlled study.
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Hernia; Local anesthesia; ultrasound