Lumbar Disc Degeneration Induces Persistent Groin Pain

This is an interesting study.  there are many causes of inguinal pain.  this is a surprising result, because the innervation level of the inguinal area is higher in the spine, such as T12-L1-L2 and this report speaks of fusions at L4-L5.  These results are surprising and are sure to provoke conversation.

Spine:  15 January 2012 - Volume 37 - Issue 2 - p
114–118  doi:  10.1097/BRS.0b013e318210e6b5
Clinical Case Series
Lumbar Disc Degeneration Induces Persistent Groin  Pain
Oikawa, Yasuhiro MD; Ohtori, Seiji MD, PhD; Koshi, Takana MD, PhD; Takaso, Masashi MD, PhD; Inoue, Gen MD, PhD; Orita, Sumihisa MD, PhD; Eguchi, Yawara MD, PhD; Ochiai, Nobuyasu MD, PhD; Kishida, Shunji MD, PhD; Kuniyoshi, Kazuki MD, PhD; Nakamura, Junichi MD, PhD; Aoki, Yasuchika MD, PhD; Ishikawa, Tetsuhiro MD; Miyagi, Masayuki MD; Arai, Gen MD; Kamoda, Hiroto MD; Suzuki, Miyako MD; Sainoh, Takeshi MD; Toyone, Tomoaki MD, PhD; Takahashi, Kazuhisa MD, PhD
Abstract
Study Design. Prospective study of 212 patients with groin pain but without low back pain.
Objective. To evaluate discogenic groin pain without low back pain or radicular pain.
Summary of Background Data. Patients feel low back pain originating from discogenic disease. It has been reported that the rat lower lumbar discs are innervated mainly by L2 dorsal root ganglion neurons. Thus, it is possible that patients feel referred groin pain corresponding to the L2 dermatome originating from intervertebral discs; however, the referred pain has not been fully clarified in humans.
Methods. We selected 5 patients with groin pain alone for investigation. The patients suffered from groin pain and showed disc degeneration only at 1 level (L4-L5 or L5-S1) on magnetic resonance imaging.
Patients did not show any hip joint abnormality on radiography or magnetic resonance imaging. To prove that their groin pain originated in degenerated intervertebral discs, we evaluated changes in groin pain after infiltration of lidocaine into hip joints and examined pain provocation on discography, pain relief by anesthetic discoblock, and finally anterior lumbar interbody fusion surgery.
Results. All patients were negative for hip joint block, positive for pain provocation on discography, and positive for pain relief by anesthetic discoblock. Furthermore, bony union was achieved 1 year after anterior interbody fusion surgery in all patients, and visual analogue scale score of groin pain was significantly improved at 1 year after surgery in all patients (P < 0.05).
Conclusion. In the current study, we diagnosed discogenic groin pain, using magnetic resonance imaging, infiltration of lidocaine into the hip joint, pain provocation on discography, pain relief by anesthetic discoblock, and lumbar surgery. It is important to consider the existence of discogenic groin pain if patients do not show low back pain.