Lower-extremity sensibility testing in patients with herniated lumbar intervertebral discs

Area of Science:

• Neurology
• Orthopedics
• Diagnostic Medicine

Background:

• The diagnostic accuracy of sensory testing for herniated lumbar discs is debated.
• Traditional methods like pinprick and light touch show inconsistencies due to subjectivity and anatomical overlap.
• Need for reliable sensory examination techniques to pinpoint nerve root compression.

Purpose of the Study:

• To evaluate the efficacy of different sensory testing methods in identifying compressed nerve roots in patients with lumbar disc herniation.
• To compare the diagnostic accuracy of Semmes-Weinstein monofilaments, vibrometry, pinprick, and light touch.

Main Methods:

• Twenty-five patients with confirmed lumbar disc herniation underwent sensory examinations.
• Testing included Semmes-Weinstein pressure thresholds, vibrometry, pinprick, and light touch.
• Tests were performed on specific dermatomes corresponding to the L4, L5, and S1 nerve roots.

Main Results:

• Semmes-Weinstein testing identified the affected nerve root in 100% of patients when differences exceeded 15 mg/mm².
• Vibrometry correctly localized the disc lesion level in 88% of patients with threshold differences >3.5 µm.
• Light touch and pinprick tests showed low accuracy (50%) in identifying the compressed nerve root.

Conclusions:

• Semmes-Weinstein pressure aesthesiometry and vibrometry are superior to pinprick and light touch for diagnosing lumbar disc herniation.
• Quantitative sensory testing methods offer improved localization of nerve root compression.
• Further refinement of sensory testing techniques is needed for consistent diagnostic accuracy.