Extraforaminal Lumbar Disk Herniations Lead To Neuroplastic Changes: a Study Using Quantitative Sensory Testing
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Updated: Feb 7, 2026

Transtubular Endoscopic Posterolateral Decompression for L5-S1 Lumbar Lateral Disc Herniation
Published on: October 14, 2022
Anja Tschugg1, Sara Lener1, Sebastian Hartmann1
1Department of Neurosurgery, Innsbruck Medical University, Anichstrasse 35, A-6020, Innsbruck, Austria.
Introduction:
Extraforaminal lumbar disk herniations are characterized by distinct clinical features in comparison to paramedian lumbar disk herniations.
Methods:
We applied the quantitative sensory testing (QST) protocol of the German Research Network on Neuropathic Pain in 63 patients with a single lumbar disk herniation. They were categorized in 2 groups: (I) an intraspinal (group I; n = 47, 75%) and an extraforaminal (group E; n = 16, 25%).
Results:
The wind-up ratio for assessing endogenous pain-modulating pathways was higher in group E (2.9 ± 2) than in group I (1.4 ± 1; P = 0.021). After a subsequent series of pinprick stimuli, an increase in pain assessed by the numeric rating scale could be shown in group E (2.1 ± 2 vs 1.1 ± 1; P = 0.032).
Discussion:
Extraforaminal compression is associated with chronic as well as neuropathic pain, presumably caused by direct compression of the dorsal root ganglion, which may preferentially promote specific chronic pain mechanisms. Muscle Nerve 58: 676-680, 2018.
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