Nerves in quadratus lumborum planes: A cadaveric study.

Area of Science:

• Anatomy
• Regional Anesthesia
• Pain Management

Background:

• Quadratus lumborum blocks (QLBs) are increasingly used for abdominal and hip analgesia.
• The precise anatomical targets for QLBs remain debated, contributing to variable clinical outcomes.

Purpose of the Study:

• To identify consistent neural structures adjacent to the quadratus lumborum muscle (QLM) for improved block targeting.
• To elucidate the anatomical basis for dermatomal analgesia variability with QLBs.

Main Methods:

• Bilateral dissection of six fresh human cadavers.
• Detailed examination of neurological linkages to the quadratus lumborum muscle (QLM).
• Identification and documentation of all neural structures in proximity to the QLM and its fascial planes.

Main Results:

• The subcostal nerve and ilioinguinal nerves were consistently found near the QLM in all specimens.
• The iliohypogastric nerve was identified in only two specimens.
• No other neural targets were consistently identified in the fascial planes anterior or posterior to the QLM.

Conclusions:

• The consistent presence of the subcostal and ilioinguinal nerves near the QLM offers potential targets for more reliable block placement.
• Variability in QLB efficacy may be partly explained by inconsistent targeting of the iliohypogastric nerve and the absence of other reliable neural targets in the investigated fascial planes.