Volume Versus Concentration: Clinical Effectiveness of Single Shot Quadrates Lumborum Block Using Either a High Volume/Low Concentration or Low Volume/High Concentration Injectate for Total Hip Arthroplasty.
Condition: Acute Pain
MeSH terms: Acute Pain
Study type: Interventional
Phase: Phase 4

Summary: 
      There is Controversy about what is more critical volume or concentration to achieve an
      optimum analgesic treatment with quadratus lumborum block. From the experiences of the
      authors, the regular dose of 20 ml of Bupivacaine at 0.375% concentration could not be enough
      in some cases to produce an optimum analgesic treatment, especially in hip arthroplasties.
      What is proposed in this study is to evaluate whether the volume injected in the quadratus
      lumborum block is more important than the concentration of the local anesthetic in terms of
      control of pain during the next 24 hours after surgery and opioid consumption.
    

Detailed description: 
      The Quadratus Lumborum Block (QLB) was originally described by Blanco in 2007 as a posterior
      variation of the Transversus Abdominis Plane block. It is now, however, recognized as a
      unique, alternative, and separate interfascial plane block. The QLB has been studied and
      compared with other types of blocks and it may offer several advantages such as simplicity,
      safety, and avoidance of hypotension. Additionally, dermatomal coverage may be greater than
      for other types of blocks. In cadaveric studies the paravertebral spread of dye was found
      from T7-L5 , although an vivo study in healthy volunteers showed the paravertebral spread of
      the contrast solution only between T10-L1 at 1 hour after the block. It is noted that while
      these anatomical studies invariably show the spread of contrast or dye extending to the
      paravertebral space that spread may be limited in degree. Thus follows a point of significant
      controversy as to whether the paravertebral space is in fact the block's primary site of
      action or whether it acts primarily on nerves, radicular and sympathetic, situated in the
      thoracolumbar fascia. Questions of mechanism and site of action notwithstanding, the safety
      and clinical efficacy of this block has been clearly demonstrated in multiple types of
      surgeries including abdominal laparoscopic , open laparotomy , urologic , and general surgery
      with analgesia lasting roughly 24 hours, decreased consumption of opioids, decreased time to
      ambulation, and decreased hospital length of stay. In recent studies, QL block employment was
      shown to produce a significant reduction in length of stay during hip surgery as well as
      similar analgesia to Lumbar Plexus blockade.

      The quadratus lumborum block has since 2016 become standard of care for abdominal and hip
      surgeries at our institution, replacing paravertebral and lumbar plexus blocks respectively,
      and as part of a broader multimodal analgesia institutional ERAS (Enhanced Recovery After
      Surgery) protocol. Coincident with its implementation we have seen significant reductions in
      opiate and PCA use as well as hospital length of stay. Similar results have been reported by
      other institutions.

      Since the first description of this technique, several approaches to and anatomic targets
      within the quadratus lumborum plane have been described although their mechanism of action,
      spread, and relative clinical effectiveness remain areas of some debate. There remain many
      unanswered questions regarding this block and its subtypes. It is, for example, unknown if
      one technique would be better than another for different types of surgery. Likewise little is
      known of the relative importance of local anesthetic concentration and injectate volume - the
      principal question addressed by this proposed study.
    

Intervention name(s): Drug: Bupivacaine 0.375% 20 mL; Drug: Bupivacaine 0.375%
Intervention type(s): Drug; Drug
Intervention description(s): Each block of 0.375% Bupivacaine x 20 mL; Each block of 0.375% Bupivacaine x 20 ml + Normal Saline Solution 20 mL
Intervention MeSH terms: Bupivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: The study will be conducted as a prospective, randomized, double blinded, parallel trial at the University of Pittsburgh Medical Center (UPMC) Shadyside Hospital.
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Hip; Anesthesia,conduction; arthroplasty