Symptomatic ossification of the posterior longitudinal ligament of the lumbar spine. Case report

Cyclic tensile strain facilitates ossification of the cervical posterior longitudinal ligament via increased Indian hedgehog signaling

The pathomechanisms of initiation and progression of ossification of the posterior longitudinal ligament (OPLL) are unclear. Indian hedgehog (Ihh) and related signaling molecules are key factors in normal enchondral ossification. The purpose of this study is to investigate the contribution of mechanical strain to OPLL and the relationship of Ihh with OPLL. Sections of the posterior longitudinal ligament (PLL) were obtained from 49 patients with OPLL and from 7 patients without OPLL. Cultured PLL cells were subjected to 24 hours of cyclic tensile strain. To identify differentially expressed genes associated with cyclic tensile strain, microarray analysis was performed. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis identified upregulation of various genes, particularly of the Hedgehog signaling pathway; Ihh and related genes had increased expression compared with controls after 24-hour cyclic tensile strain. In immunoblotting analysis, Ihh, Runx2, Sox9, Gli2, Gli3, and smoothened (SMO) had significantly increased expression after 6- or 12-hour cyclic tensile strain. OPLL samples were strongly immunopositive for Ihh, Sox9, Runx2, Gli2, Gli3, and SMO in the ossification front of OPLL. These results suggest that cyclic tensile strain induces abnormal activation of Ihh and related signaling molecules, and this might be important in the ossification process in OPLL.

A higher frequency of lumbar ossification of the posterior longitudinal ligament in elderly in an outpatient clinic in Japan

Purpose

Little is known about the prevalence and epidemiological characteristics of lumbar ossification of the posterior longitudinal ligament (OPLL). We analyzed the rate of lumbar OPLL in an outpatient unit where primary care physicians are working in Japan, to better understand the epidemiological characteristics of the disease.

Methods

We analyzed consecutive, first-time visiting outpatients who received abdominal and pelvic computed tomography (CT) scan at the Department of General Medicine, Asahikawa Medical University Hospital, Japan, between April 2009 and March 2012. Each parameter such as age, sex, and clinical presentation was investigated.

Results

Out of 393 patients who underwent abdominal and pelvic CT scan, 33 (8.4%) were diagnosed as lumbar OPLL. When compared with patients without lumbar OPLL (n = 360), there was no significant difference in gender, body mass index (BMI), presence of hypertension, diabetes mellitus or hyperlipidemia, and smoking habit, while the age in patients with lumbar OPLL was significantly higher.

Conclusion

These results suggest for the first time that lumbar OPLL is frequently observed in elderly people in the primary care setting, in Japan.

Ossification of the posterior longitudinal and yellow ligaments on the lumbar spine

Ossification of the posterior longitudinal ligament and ossification of the yellow ligament are the main causes of spinal canal stenosis. This article describes a case of ossification of the posterior longitudinal and yellow ligaments on the lumbar spine. The patient presented with gradually worsening left lower-extremity ache and pain. The deep tendon reflex was hyperreflexia in the lower extremities. Disturbances existed in the blade and bowel. The ossified lesion of ossification of the posterior longitudinal ligament was observed at L5-S1, and plain lateral radiographs and computed tomography revealed ossification of the yellow ligament on L3, which occupied a large part of the spinal canal. Because of the findings on the preoperative radiographs, we performed posterior approach decompression and bone grafting and excisied the ossified lesion. Pedicle screws were inserted from L3 to S1. The patient's symptoms disappeared postoperatively, and his Japanese Orthopaedic Association score was 25 two weeks postoperatively. No standard surgical procedure exists for the treatment of lumbar ossification of the posterior longitudinal ligament, but it is important to select a surgical procedure according to individual patient conditions. Many factors, such as local mechanic stress, tissue metabolism, high glucose, and genetics, contribute to the progression of ossification of the posterior longitudinal and yellow ligaments on the lumbar spine. However, the mechanism is unclear. Further study and long-term follow-up on lumbar ossification of the posterior longitudinal ligament is needed.

Surgical treatment of lumbar ossification of the posterior longitudinal ligament

✓ The authors report two cases of patients with lumbar ossification of the posterior longitudinal ligament (OPLL). One patient underwent surgery via the single posterior approach, and the other patient underwent combined anterior—posterior surgery. The authors consider the anterior approach for excision of the ossified lesion to be the most reasonable for treatment of lumbar OPLL. It is extremely important, however, to select the surgical procedure according to the individual patient's condition.