These results suggest that peripheral blood mononuclear cells infiltrating extruded discs may secrete a variety of biologic materials capable of further recruiting monocytes into herniated discs in an autocrine fashion. Disc cells stimulated with cytokines showed enhanced production of matrix metalloproteinases, which might play an important role in spontaneous regression of disc materials.

Relationship between lumbar disc degeneration and segmental instability has remained controversial. Using instability factors that found close relations with symptoms in flexion-extension radiographic study, their relationship with degenerative findings was examined. More than (≥) 3 mm slip in neutral position (SN), ≥3 mm translation (ST), and ≥10° angulation (SA) at L4/5 segment were defined as instability factors and were applied on 447 patients who had low back and/or leg pain and satisfied inclusion criteria for accurate measurements. Radiologic findings for degeneration were disc height including three groups with different disc heights divided by mean ± 1 standard deviation, length of the anterior spur formation, presence of vacuum phenomenon, and endplate sclerosis. As results, group with SN factor was the oldest in age and the lowest in disc height; in contrast, group with SA was the youngest in age and the highest in disc height. The group with ST showed a mid-standing position in both age and disc height. These findings indicate that instability factors are intimately related to age and disc height. The three different disc height groups showed more anterior slip according to the progression of the disc height diminution. Presence of the apparent spur formation and/or vacuum phenomenon had an intimate relationship with the ST factor. Disc height was the most important in the examined parameters and showed an intimate relationship with age and instability factors. Although the etiology is still unknown, clinical common knowledge, that a diminution of disc height with progressive degeneration had a close relation with anterior vertebral slippage, was firstly confirmed. This study allows comprehensive understanding of segmental instability and is useful for considering surgical indications.

The incidences of VS and SAS significantly increased during the minimum 5-year follow-up. Prognostic factors of these instabilities were revealed to be the initial radiological findings of VS, SAS, and mutilating changes.

Introduction Little is known about when and how progressive spondylolisthesis occurs. In this report segmental motion related to age and disc degeneration at L4/5 disc was investigated. Materials and methods 637 patients with low back and/or leg pain underwent radiologic and MRI examinations simultaneously. Because 190 patients with conditions which might impede accurate measurement were excluded, 447 patients, comprising 268 men and 179 women, were included; age range, was 10-86 (mean: 53) years. Three radiologic parameters slip in neutral position (mm), sagittal translation (mm), and segmental angulation (degrees) were examined at the L4/5 segment. On T2-weighted MRI, severity of disc degeneration at L4/5 was classified by Pfirrmann's criteria, grade 1-5. Results Results showed stage of disc degeneration that progressed according to aging with significant differences except for between grades 4 and 5. Amount of anterior slip was small among grades 1 to 3; however, it greatly increased between grades 3 and 4 and between grades 4 and 5, suggesting that grade 3 disc degeneration has a potential risk of future progression of anterior slip. This finding may also suggest that once significant slip occurs, it will progress to the final grade. Furthermore, the grade 3 degeneration group exhibited large amounts of motion in both angulation and translation, suggesting it was the most unstable group. Conclusion Our results with radiography and MRI indicate that grade 3 disc degeneration is a critical stage for the progression of lumbar spondylolisthesis at L4/5 segment.

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This is a report of recurrent dislocation of the peroneal tendon in a patient with multiple osteochondromatosis. The distorted anatomy at the ankle from the osteochondromas was the source of the tendon's recurrent dislocations. There were two areas in the ankle in which the retinacula supporting the tendons failed because of the osteochondromas. At the lateral site of fibula, the origin of the supporting retinacula was attenuated by the presence of an osteochondromas. At the medial site of fibula, a large osteochondroma distorted and widened the tibiofibular joint. The widening of the distal tibiofibular joint by this osteochondromas also attenuated the retinacula of the peroneal tendons, permitting their dislocation.

Two experiments were performed to document the time-dependent characteristics of the peroneus longus short latency stretch reflex amplitude following application of an ankle brace. In Experiment I , stretch reflexes were induced in 15 weightbearing subjects during an unbraced condition and braced condition. In Experiment 2, stretch reflexes were induced in 15 weightbearing subjects before and after 3 h of wearing the brace. In Experiment 1, the amplitude of the stretch reflex increased in the braced condition by about 25% relative to the non-braced condition ( p = 0.006). In Experiment 2 the amplitude of the stretch reflex increased about IS'% immediately after application of the brace relative to the non-braced condition ( p = 0.037). After 3 h, the stretch reflex amplitude was not different from that of initial non-braced condition. Given the importance of the peroneus longus muscle in ankle complex stability, further attention should be directed to whether the increased stretch reflex gain can be exploited during rehabilitation from ankle complex injuries. The findings provide a framework by which the effect of ankle braces on ankle joint proprioception, muscle activation profiles and balance may be physiologically interpreted.

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