Defining a bony landmark-based target zone for superior cluneal nerve blockade: a cadaveric mapping study

Area of Science:

• Anatomy
• Pain Management
• Interventional Radiology

Background:

• Superior cluneal nerve (SCN) entrapment causes gluteal pain and dysesthesia.
• Ultrasound-guided injection is the primary treatment for SCN entrapment.
• Precise mapping of SCN branches is crucial for effective anesthetic injection.

Purpose of the Study:

• To map the anatomical emergence sites of superior cluneal nerve branches.
• To identify optimal landmarks for ultrasound-guided injections in SCN entrapment.

Main Methods:

• Dissection of 10 lumbar-gluteal regions from six cadavers using a surgical microscope.
• Establishment of a Cartesian coordinate system relative to the posterior superior iliac spine (PSIS).
• Mapping SCN branch emergence points in relation to the iliac crest and PSIS.

Main Results:

• SCN branches emerged from the thoracolumbar fascia at a mean lateral distance of 6.6 cm and vertical distance of 6.8 cm from the reference line.
• The reference line connecting the PSIS to the iliac crest's highest point averaged 9.2 cm.
• No SCN branches were identified within the triangle of Petit.

Conclusions:

• Targeting the lateral half of the reference line over the iliac crest within a 3 cm² area is recommended for high-success SCN entrapment injections.
• Anatomical mapping aids in precise needle placement for superior cluneal nerve interventions.