Effect of Posterior Dynamic Instrumentation on High-Intensity Zone in Lumbar Degenerative Disc Disease

Radiological outcomes of PEEK rods in patients with lumbar degenerative diseases: A minimum 5-year follow-up

Purpose

To determine the long-term radiological outcomes of PEEK rods in patients with lumbar degenerative diseases.

Methods

Radiological outcomes of cohort cases with lumbar degenerative diseases following PEEK rods were retrospectively studied. Disc height index (DHI) and range of motion (ROM) were measured by x-rays. The CT scans and reconstruction were used to determine screw breakage, rods fracture, screw loosening and intervertebral bony fusion status. The MRI scans were used to evaluate the changes of intervertebral discs at the non-fusion segments and adjacent segments in terms of Pfirrmann Classification.

Results

A total of 40 patients completed the mean of 74.8 ± 9.6 months follow-up, with 32 patients undergoing hybrid surgery and 8 patients undergoing non-fusion surgery. The mean DHI changed from preoperative 0.34 to 0.36 at the final follow-up and the ROM declined from 8.8° preoperatively to 3.2° at the final visit, however, both had no statistical differences. Of the 40 levels underwent non-fusion procedure, 9 levels showed disc rehydration with 7 patients from Grade 4 to Grade 3 and 2 patients from Grade 3 to Grade 2. The other 30 cases did not show distinctive change. No screw loosening or rods breakage were detected during the follow-up periods.

Conclusion

PEEK rods have obvious protective effects on degenerated intervertebral disc of non-fusion segments and the incidence of complications related to internal fixation is low. PEEK rods pedicle screw system is safe and effective in the treatment of lumbar degenerative diseases.

Lumbar disc rehydration in the bridged segment using the BioFlex dynamic stabilization system: A case report and literature review

BACKGROUND

In recent years, the mechanical concept of intervertebral disc regeneration has become more and more popular due to the increasing awareness of the importance of preservation of spine movement. Interestingly, there is increasing evidence, however, that dynamic stabilization systems may compensate non-physiological loads, limit pathological movement, normalize disc height and intradiscal pressure, and provide an adaptive environment for disc regeneration.

CASE SUMMARY

The patient was a 54-year-old man, who presented with a 10-year history of mechanical back pain, which had become progressively serious and radiated into the left lower limb with numbness 3 mo prior. He had decreased muscle strength (class IV) of the left dorsal extensor and plantar flexor. Magnetic resonance imaging scans showed L3-S1 disc degeneration and L4-L5 disc herniation. Because the patient did not respond to various conservative treatments, he underwent a posterior L4-5 discectomy with fixation of the BioFlex dynamic stabilization system (Bio-Spine, Seoul, Korea). Preoperative symptoms were relieved and lumbar function was markedly improved after the operation. L4-L5 disc rehydration of instrumented segment was noted on magnetic resonance imaging at the 2-year follow-up.

CONCLUSION

Rehydration of the degenerated disc in our patient indicates that the BioFlex dynamic stabilization system may promote disc regeneration. Further research is needed to provide more evidence to support lumbar disc rehydration in the bridged segment using this system.

The relevance of high-intensity zones in degenerative disc disease

PURPOSE

The purpose of this study was to review the current understanding of high-intensity zones (HIZ) in the lumbar spine with particular attention to its imaging phenotype and clinical relevance.

METHODS

A review was conducted of studies related to HIZ. Particular attention was made to imaging phenotypes and classification, and its relationship with discogenic low back pain (LBP).

RESULTS

The most current classification system of HIZ is based on location (anterior and posterior), morphology (round, fissure, vertical, rim, or giant types), and its appearance on both T1- and T2-weighted magnetic resonance imaging (MRI). HIZ are commonly manifested with disc degeneration. Hence, both conditions share similar risk factors such as the effect of frequent and prolonged disc loading. The clinical significance of HIZ however is not conclusive. Provocative discography is not sensitive (~ 70%) for eliciting a concordant pain response. Population-based studies have conflicting results regarding the prevalence (14-63%) of HIZ and its correlation with LBP.

CONCLUSIONS

HIZ are likely a risk factor for discogenic LBP. However, its etiology and pathophysiology are not well understood. Some clinical studies suggest a link between its occurrence and LBP. However, the results are not consistent as a result of studies which are underpowered and based on heterogeneous study populations, lacking control groups, and without standardized imaging phenotypes. HIZ may be an important pain biomarker that should be further studied. With more modern MRI technology and a detailed classification system, future large-scale population studies will improve our knowledge on its role in the disc degeneration cascade and development of LBP.