Distribution of cavitations as identified with accelerometry during lumbar spinal manipulation

Area of Science:

• Biomechanics
• Spinal Manipulation
• Musculoskeletal System

Background:

• Spinal manipulative therapy (SMT) is a common treatment for back pain.
• The mechanism of SMT, particularly the occurrence of cavitations in zygapophyseal joints, is not fully understood.
• Cavitations, characterized by vibrations and audible sounds, are thought to be a key event during SMT.

Purpose of the Study:

• To determine the precise location and distribution of cavitations within the lumbar zygapophyseal (Z) joints during SMT.
• To compare cavitation occurrence between SMT and a control group receiving only side-posture positioning.

Main Methods:

• A randomized, controlled clinical study involving 40 healthy young adults.
• Nine accelerometers were used to record vibrations from L1-S2 spinal segments during SMT and control positioning.
• Statistical analysis compared cavitation rates between SMT and control groups, and between different spinal locations (upside vs. downside, target vs. non-target areas).

Main Results:

• A total of 56 cavitations were recorded from 46 joints across 40 subjects.
• SMT significantly increased cavitation frequency compared to the control group (96.7% vs. 30%).
• Cavitations were more prevalent on the contact (upside) side and within the targeted L3/L4, L4/L5, and L5/S1 segments.

Conclusions:

• SMT demonstrably causes cavitations in lumbar zygapophyseal joints, primarily on the contact side and within the targeted spinal region.
• The findings confirm that SMT is a potent stimulus for joint cavitation.
• The study also reported the novel finding of multiple cavitations occurring in the same Z joint, a phenomenon not previously documented.