Correspondence Address:
Nita D'souza
Department of Anaesthesia, Ruby Hall Clinic, 40, Sasoon Road, Sangamwadi, Pune, Maharashtra - 411 001
India

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Ultrasound guided quadratus lumborum block was first introduced by Blanco R in 2007 where local anesthetic was injected adjacent to the quadratus lumborum (QL) muscle with the goal of anesthetizing the thoracolumbar nerves.[1] A curvilinear transducer is preferred as they have a divergent ultrasound beam resulting in a wider field of view. QLB was performed with the patient in lateral position commonly, targeting the paravertebral muscles around the transverse process seen as the “Shamrock.”[2] Positioning the anesthetized patient in lateral decubitus is cumbersome as there is increased manpower requirement, accidental tube displacement, circuit disconnection and it is time-consuming especially in a busy OR schedule. More so over when required to be administered bilaterally.

We have successfully administered anterior QL blocks in supine position in over 70 cases of various abdominal surgeries like laparoscopic ventral hernias, lower segment cesarean sections, laparoscopic hysterectomies, renal transplants, laparotomies, gall bladder surgeries. Anterior QL block in supine position has been reported earlier; however, the specifications of sonoanatomy and challenges faced in supine position are not highlighted.[3],[4] We wish to highlight the pros and cons of administering the anterior QLB in supine position.

We suggest using the supine position in all abdominal surgeries warranting bilateral blocks for post-operative analgesia. The advantages being: avoiding patient position change under anesthesia, avoiding endotracheal tube dislodgement, limiting the need for more manpower and being more cost-effective (limits OR time). The scanning technique adopted a curvilinear probe to be placed in transverse orientation over the flank immediately above the iliac crest. All three muscles of the abdomen are identified and the probe is slid toward the midaxillary line. Once the QL muscle is located below the anterior abdominal muscles, the probe is further slid toward the posterior axillary line till the transverse process of lumbar vertebra is visualized. The QL muscle appears like a leafy attachment to the transverse process of the lumbar vertebra with the psoas major also in view. Needling done is anterior to posterior or accurately anterolateral to posteromedial correlating with the sonoanatomy [Figure 1].{Figure 1}

Expertise in ensuring that the needling done is in plane is cautiously performed, as it is a deep block and lumbar vessels may be inadvertent. Drug spread is confirmed by rotating the probe 90° from transverse plane to coronal longitudinal plane, observing for drug spread in cephalon-caudad direction. Although performing the block with probe in coronal longitudinal orientation is mentioned in literature, it may be technically challenging to maintain/anchor the probe in this position.[3] Additionally certainty in achieving drug spread more medially between the anterior aspect of the QL muscle and the Psoas may not be consistent in coronal longitudinal position of the probe. This may cause drug spread more lateral as there is difficulty in identifying anterior aspect of QL. All the blocks thus performed were assessed using VAS score, need for rescue analgesic, comfort levels, ambulation, and duration. Comparable analgesia was obtained in supine position QLB as with lateral position QLB.

Attempts at avoiding the renal lower pole acoustic shadow are possible by caudad angulation (looking into the pelvis). However, avoiding the sliding peritoneum and content just anterolateral to the QL is challenging. An attempt to target the tip of transverse process enables avoiding the peritoneum and inadvertently injecting the local anaesthetic in the prerenal tissue, missing the desired spread anterior to the QL muscle over the anterior thoracolumbar fascia.

The knowledge of the exact technique of the anterior QLB in supine position (differences in the visualized sonoanatomy), advantages, disadvantageous, challenges faced in performing the anterior QLB will enhance the use of this block for a wide range of abdominal surgeries with better success rates and being cost and manpower effective.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

References