Do human lumbar discs reconstitute after chemonucleolysis? A 7-year follow-up study

Enzymatic chemonucleolysis for lumbar disc herniation-an assessment of historical and contemporary efficacy and safety: a systematic review and meta-analysis

Lumbar disc herniation (LDH) is often managed surgically. Enzymatic chemonucleolysis emerged as a non-surgical alternative. This systematic review and meta-analysis aims to assess the efficacy and safety of chemonucleolytic enzymes for LDH. The primary objective is to evaluate efficacy through "treatment success" (i.e., pain reduction) and severe adverse events (SAEs) rates. Additionally, differences in efficacy and safety trends among chemonucleolytic enzymes are explored. Following our PROSPERO registered protocol (CRD42023451546) and PRISMA guidelines, a systematic search of PubMed and Web of Science databases was conducted up to July 18, 2023. Inclusion criteria involved human LDH treatment with enzymatic chemonucleolysis reagents, assessing pain alleviation, imaging changes, and reporting on SAEs, with focus on allergic reactions. Quality assessment employed the Cochrane Source of Bias and MINORS tools. Meta-analysis utilized odds ratios (OR) with 95% confidence intervals (CI). Among 62 included studies (12,368 patients), chemonucleolysis demonstrated an 79% treatment success rate and significantly outperformed placebo controls (OR 3.35, 95% CI 2.41-4.65) and scored similar to surgical interventions (OR 0.65, 95% CI 0.20-2.10). SAEs occurred in 1.4% of cases, with slightly higher rates in chymopapain cohorts. No significant differences in "proceeding to surgery" rates were observed between chemonucleolysis and control cohorts. Limitations include dated and heterogeneous studies, emphasizing the need for higher-quality trials. Further optimization through careful patient selection and advances in therapy implementation may further enhance outcomes. The observed benefits call for wider clinical exploration and adoption. No funding was received for this review.

A hydrogel reservoir as a self-contained nucleus pulposus cell delivery vehicle for immunoregulation and repair of degenerated intervertebral disc

The strategies for modulating the local inflammatory microenvironment to inhibit intervertebral disc degeneration (IVDD) have garnered significant interest in recent years. In this study, we developed a "self-contained" injectable hydrogel capable of storing Mg2+ while carrying nucleus pulposus (NP) cells, with the aim of inhibiting IVDD through immunoregulation. The hydrogel consists of sodium alginate (SA), poly(N-isopropylacrylamide) (PNIPAAm), silicate ceramics (SC), and NP cells. When injected into the NP site, PNIPAAm gelates instantly under body temperature, forming an interpenetrating network (IPN) hydrogel with SA. Ca2+ released from the SC can crosslink the SA in situ, forming a SA/PNIPAAm hydrogel with an interpenetrating network (IPN) encapsulating the NP cells. Moreover, inside the hydrogel, Mg2+ released from SC are effectively encapsulated and maintained at a desirable concentration. These Mg2+ facilitates the local cell matrix synthesis and promotes immunomodulation (upregulating M2 / downregulating M1 macrophage polarization), thus inhibiting the IVDD progression. The proposed hydrogel has biocompatibility and is shown to enhance the expression of collagen II (COL II) and aggrecan. The potential of the injectable hydrogel in IVD repair has also been successfully demonstrated by in vivo studies. STATEMENT OF SIGNIFICANCE.

An interpenetrating network-strengthened and toughened hydrogel that supports cell-based nucleus pulposus regeneration

Hydrogel is a suitable scaffold for the nucleus pulposus (NP) regeneration. However, its unmatched mechanical properties lead to implant failure in late-stage disc degeneration because of structural failure and implant extrusion after long-term compression. In this study, we evaluated an interpenetrating network (IPN)-strengthened and toughened hydrogel for NP regeneration, using dextran and gelatin as the primary network while poly (ethylene glycol) as the secondary network. The aim of this study was to realize the NP regeneration using the hydrogel. To achieve this, we optimized its properties by adjusting the mass ratios of the secondary/primary networks and determining the best preparation conditions for NP regeneration in a series of biomechanical, cytocompatibility, tissue engineering, and in vivo study. We found the optimal formulation of the IPN hydrogel, at a secondary/primary network ratio of 1:4, exhibited high toughness (the compressive strain reached 86%). The encapsulated NP cells showed increasing proliferation, cell clustering and matrix deposition. Furthermore, the hydrogel could support long-term cell retention and survival in the rat IVDs. It facilitated rehydration and regeneration of porcine degenerative NPs. In conclusion, this study demonstrates the tough IPN hydrogel could be a promising candidate for functional disc regeneration in future.

A quantitative study of intervertebral disc morphologic changes following plasma-mediated percutaneous discectomy

OBJECTIVE

To quantitatively evaluate interval magnetic resonance imaging (MRI) changes in disc morphology following plasma-mediated percutaneous discectomy.

DESIGN/SETTING

A retrospective comparison of pretreatment and posttreatment MRIs at a single university spine clinic.

SUBJECTS

From a group of 60 consecutively treated patients, 15 met the study inclusion and exclusion criteria. All had either failed treatment or had other clinical reasons for a posttreatment MRI.

METHODS

Two independent physicians electronically measured disc protrusion size and disc height at the treatment discs and adjacent discs on pre- and posttreatment MRI scans. Additionally, images were compared for gross anatomic changes including disc degeneration by Pfirrman classification, new disc herniations, high intensity zone (HIZ), vertebral endplate changes, post-contrast enhancement, and changes in segmental alignment. Pearson r correlation was used to determine interobserver reliability between the two physicians' MRI measurements. Paired t-tests were calculated for comparisons of pre- and posttreatment MRI measurements, and an ANOVA was performed for comparison of pre- to posttreatment changes in disc height measurements at treatment levels relative to adjacent levels.

RESULTS

Correlation was high for measurement of disc height change (r = 0.89; P < 0.0001) and good for anteroposterior protrusion size change (r = 0.51; P = 0.0512). Disc height at treated discs demonstrated a small but statistically significant mean interval reduction of 0.48 mm (P = 0.0018). This remained significant when compared with the adjacent control discs (P < 0.0001). Pretreatment mean disc protrusion size (4.74 mm; range 3.75-6.55 mm) did not differ significantly (P = 0.1145) from posttreatment protrusion size (4.42 mm; range 2.55-7.95 mm). Gross anatomic changes at treatment levels included reduced disc protrusion size (N = 6), enlarged protrusion (N = 3), resolution of HIZ (N = 3), and improvement in endplate signal changes (N = 1). Also, 11/15 posttreatment MRIs included post-contrast images that showed epidural fibrosis (N = 1), rim enhancement (N = 2), and enhancement of the posterior annulus (N = 4).

CONCLUSIONS

Based on MRI examinations, subtle anatomic changes may occur following plasma-mediated percutaneous discectomy. Further study is required to determine the clinical relevance of these changes.

Radiographic changes in the lumbar spine in former professional football players: a comparative and matched controlled study

Heavy physical work and activity lead to degenerative changes, especially in the lumbar spine. We aimed to find out the occurence of radiographic changes (vertebral osteophytes, heights of lumbar dicsc, concavity index) and abnormalities of the lumbar spine in former professional football (association football or soccer) players according to their specialization (goalkeeper, defender, midfielder, forward) in their past professional sport life. We included 70 male former professional football players and 59 men as the control group. The football players group consisted of 15 defenders (21%), 29 midfielders (41%), 18 forwards (26%) and 8 goalkeepers (12%). Their mean professional football life was 11.04 years and the mean time period after their retirement was 13.87 years. Radiographs of both groups were taken to measure the disc height, concavity index and to determine osteophytes and abnormalities of the lumbar spine. FFbH-R score was assessed for daily activities. The mean FFbH-R score of football players was lower than that of the control group (P = 0.005). The total number of osteophytes in the player group was higher than in the control group (P = 0.001). The mean disc height of L1-L2 in football players was higher than in the control group (P = 0.045). The mean disc height of T12-L1 in goalkeepers was higher than in forward players (P = 0.019). The mean concavity index of L1 in forward players was lower than in defenders (P = 0.018). The mean disc heights of T12-L1 and L2-L3 were both higher in players whose professional sport life was >10 years than in players with </=10 years (P = 0.018, P = 0.016). The mean disc height of L5-S1 was higher in players who had continued sport activity after retirement (P = 0.025). No statistically significant result was obtained with the rest of the variables. Playing football is heavy work. The decreased height of lumbar discs and the lower value of concavity index of forward players are because the lumbar spine of forward players is loaded more than in the rest of the players.

Radiographic changes in the lumbar spine in former elite athletes

STUDY DESIGN

The authors conducted a retrospective cohort study.

OBJECTIVE

The objective of this study was to clarify the occurrence of radiographic changes (vertebral osteophytes, heights of lumbar discs, concavity index) of the lumbar spine in former elite athletes of different track and field disciplines.

SUMMARY OF BACKGROUND DATA

The influence of physical activity on occurrence of radiographic changes in the lumbar spine is not well known and seems to be contradictory. The loadings in the different track and field disciplines seem to play an important role in the development of radiographic changes.

METHODS

One hundred fifty-nine former male elite track and field athletes were selected for a radiologic study. The heights of lumbar discs, the concavity index, the presence of anterior vertebral osteophytes, a radiographic evaluation according to Kellgren and Lawrence, and the FFbH-R score for the assessment of functional limitations in activities of daily living (ADLs) were determined. The influence of age, body mass index, current physical activity, and training history was also examined.

RESULTS

In high jumpers and throwers, the absolute heights of lumbar discs increased from level T12/L1 to a maximum at L4/L5 and decreased again from level L4/L5-L5/S1. In endurance athletes and other jumpers, the absolute heights increased linearly from level T12/L1 to a maximum at L5/S1. The concavity index did not yield any significant differences between athlete categories. Shot putters, discus throwers, and high jumpers showed a significantly higher prevalence of osteophytes after adjustment for possible confounders. According to Kellgren and Lawrence, the highest prevalence of radiographic changes in the lumbar spine is seen in javelin throwers. Significant differences in the assessment of functional limitations in ADLs are not found between the disciplines.

CONCLUSION

In throwing disciplines, the lumbar spine is more highly loaded than in jumpers and runners. Despite the observation of evident degenerative changes in some former athletes, there were only minor changes seen in ADLs. Even if body constitution is taken as a preselection factor, athletes in throwing disciplines as well as high jumpers have a higher risk of developing vertebral osteophytes of the lumbar spine.

Radiographic changes in the lumbar intervertebral discs and lumbar vertebrae with age

STUDY DESIGN

Plain lateral radiographs of the lumbar spines of 607 women (age range 20-87 years) and 633 men (age range 20-92 years) were studied.

OBJECTIVE

To study the radiographic changes in the lumbar intervertebral discs and lumbar vertebrae with age. To compile a database of reference values for the age-dependent height of lumbar discs and concavity index of lumbar vertebral bodies as well as prevalence of vertebral osteophytes by age and sex.

SUMMARY OF BACKGROUND DATA

There is a general agreement that changes induced by aging lead to alterations in the thickness of the disc, but there are differences in the accounts of the effect of aging on the thickness of the lumbar discs. Published methods to measure disc height yield, except for some exceptional cases, inaccurate results. Reference values of disc height and concavity index of lumbar vertebral bodies, suitable for quantitative comparison with a given disc and lumbar vertebral body, have yet to be established.

METHODS

Using a new protocol with a precision of 3.9%, the anulus heights of lumbar discs were measured from sets of lateral radiographic views of 607 women and 633 men. The measurement of concavity index of vertebrae was established for each vertebral body by dividing the central vertebral height by the anterior vertebral height.

RESULTS

The heights of lumbar discs T12-L1, L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 of men and women within the age 20-69 years increased with increasing age (4.6-6.9% in men and 4.7-8.4% in women). The concavity index of vertebrae T12, L1, L2, L3, L4, and L5 of men within age 20-87 years and of women within age 20-92 years decreased linearly with increasing age (0.9-1.5% in men and 1.6-3.2% in women). In other words, the vertebral body endplates became more concave with age. The prevalence of osteophytes was greater in men than in women in lumbar spine and increased with age.

CONCLUSIONS

Using the new procedure and the database of reference values, it is possible to measure the height of lumbar discs and concavity of vertebrae objectively and precisely and to compare the results quantitatively with reference values.

Cultivation of porcine cells from the nucleus pulposus in a fibrin/hyaluronic acid matrix

Use of multiplied viable cells from the nucleus pulposus in altered discs, following in vitro cultivation, may be a promising therapy for degenerative disc disease. Up till now, alginate has been used as a three-dimensional cell carrier to cultivate nucleus pulposus cells. However, the biocompatibility of the alginate, which depends on the composition and purity of alginate materials used, has not been considered for in vivo application so far. In this study, we cultured porcine cells from the nucleus pulposus in a mixture of fibrin and hyaluronic acid (HA). The DNA content and proteoglycan synthesis were compared to those measured in an alginate matrix. Although the increase in DNA content was 2.5-fold higher in the alginate culture after 3 weeks, the proteoglycan synthesis in relation to the DNA content was significantly higher in the fibrin/HA matrix. We found that the fibrin/hyaluronic acid matrix can be used as a substrate for in vitro cultivation.