Pathomechanism of Lower-level Discogenic Groin
Pain and Clinical Outcomes of Percutaneous
Endoscopic Discectomy for the Treatment of
Discogenic Groin Pain
Authors: Wang Yansong 
Published: May 2021

Background: Groin pain can be induced by high-level (L1-L2 or L2-L3) lumbar disc herniation. However,
4.1% of patients with lower-level (L4-L5 or L5-S1) lumbar disc herniation also complained of groin pain. The
pathomechanism of groin pain occurring due to lumbar disc herniation at and below the L4-5 levels is still
unclear.
Objective: To investigate the afferent pathways of lower-level lumbar disc herniation induced groin pain.
And evaluate the clinical results of transforaminal endoscopic discectomy treatment for discogenic groin
pain.
Study Design: This retrospective observational study used an experimental design (institutional review
board: HROH 201-C2-100).
Setting: The research took place in the Laboratory Research Center and spine center at The First Affiliated
Hospital of Harbin Medical University.
Methods: Firstly, 14 adult Wistar rats were randomly divided into 2 groups: control group (the paravertebral
sympathetic trunks were preserved) and experimental group (the paravertebral sympathetic trunks were
resected). All Wistar rats were intraperitoneally anesthetized, and then 1 μL of fast blue was injected into
the dorsal rami of L2 spinal nerves on the right side. Forty hours later, 2 μL of nuclear yellow was injected
into the right posterior portion of the L5-L6 intervertebral disc. The L1 and L2 spinal ganglia were sectioned
8 hours later to observe fluorescently double-labeled cells and the effect of paravertebral sympathetic
trunk resection. Secondly, 14 adult Wistar rats were anesthetized, and the right posterior portion of the L5-
L6 intervertebral disc was electrostimulated to observe potential changes in the genitocrural nerve in the
ipsilateral inguinal region. To evaluate the clinical outcomes of transforaminal endoscopic discectomy for the
treatment of discogenic groin pain, between September 2015 and May 2017, transforaminal endoscopic
discectomy was performed on 30 patients with lower-level discogenic groin pain. Outcomes were analyzed
utilizing the visual analog scale, Oswestry disability index, and MacNab Criteria.
Results: The total proportion of cells in the right L1 and L2 spinal ganglia with fast blue/nuclear yellow
double labeling was 3.33% and 3.41% (48 and 56), respectively. The number of fluorescently doublelabeled
cells in the resected paravertebral sympathetic trunk group was significantly less (P < 0.01). Electrical
stimulation of the right posterior portion of the L5-L6 intervertebral disc could elicit action potentials in the
ipsilateral genitofemoral nerve. All patients were followed for 12 months, and the visual analog scale score
at 1 week, 1 month, 3 months, 6 months, and 12 months after the operation was 0.79 ± 0.55, 0.54 ± 0.55,
0.47 ± 0.65, 0.51 ± 0.65, and 0.69 ± 0.55, respectively, showing a significant decrease compared with the
preoperative visual analog scale score (P < 0.01). Based on the MacNab scoring system, the effective rate
was 100%, and the rate of good and excellent results was 93.3%.
Limitations: A relatively small number of patients and a short follow-up period.
Conclusions: Discogenic groin pain is transmitted by sympathetic nerves and appears in the area
segmentally innervated by the anterior rami of the L1 and L2 spinal nerves. Posterolateral percutaneous
transforaminal endoscopic discectomy and radiofrequency thermal annuloplasty are effective minimally
invasive alternative treatments for discogenic groin pain.
Key Words: Discogenic groin pain, percutaneous transforaminal endoscopic discectomy, radiofrequency
thermal annuloplasty