Evidence for infection in intervertebral disc degeneration: a systematic review

Purpose Back pain is a major problem worldwide and is linked to intervertebral disc degeneration and Modic change. Several studies report growth of bacteria following extraction of degenerate discs at spine surgery. A pathophysiological role for infection in back pain has been proposed. Method We conducted a PRISMA systematic review. MEDLINE, PubMed, Scopus and Web of Science were searched with the terms Modic change, intervertebral dis*, bacteria, microb*, and infect*. Date limits of 2001–2021 were set. Human studies investigating the role of bacteria in disc degeneration or Modic change in vertebrae were included. Results Thirty-six articles from 34 research investigations relating to bacteria in human degenerate discs were found. Cutibacterium acnes was identified in pathological disc material. A ‘candidate bacterium’ approach has been repeatedly adopted which may have biased results to find species a priori, with disc microbial evidence heavily weighted to find C. acnes. Conclusion Evidence to date implicates C. acnes identified through culture, microscopy and sequencing, with some suggestion of diverse bacterial colonisation in the disc. This review found studies which used culture methods and conventional PCR for bacterial detection. Further agnostic investigation using newer methods should be undertaken.

P.230 Modic changes and clinical outcomes in patients undergoing lumbar surgery for disc herniation

Background: Lumbar disc herniation (LDH) is a risk factor for Modic change (MC) development on spinal MRI. MC has been associated with worse pre- and post-operative pain, disability, and health-related quality of life (HRQoL). We examined the relationship between pre-operative MC and post-operative assessment scores for patients receiving discectomy (LD) or transforaminal interbody fusion (TLIF) for LDH. Methods: We reviewed 285 primary single-level surgeries. Pre-operative and 12-month post-operative assessment scores: Visual Analog Scale Leg-Pain (VAS-LP), Oswestry Disability Index (ODI), and Short-Form-36 Physical Component Summary (SF-36-PCS). MC subgroup on pre-operative MRI was recorded by a single neuroradiologist. Results: 179 patients were included. The sample prevalence of MC on pre-operative MRI was 62%; MC2 was most common (35%). No differences in pre-operative scores were identified, regardless of present or absent MC. For the overall cohort, improvement in assessment scores were observed: SF-36 improved an average of 8.2 points (95% CI: [5.8, 10.7]), ODI by 11.3 points (95% CI: [8.7, 14.0]), and VAS by 2.8 points (95% CI: [2.1, 3.5]). In nearly all cases, MCID values were met. Conclusions: Clinically significant improvement in post-operative pain, disability, and HRQoL was observed for both procedures. Modic change on pre-operative MRI was not associated with worse clinical assessment scores.

Kinematics of an intervertebral disc with type 1 Modic change: mechanical and non-mechanical causes

BackgroundType 1 Modic change (MC) is associated with chronic low back pain and attributed to segmental instability. However, the relationship between type 1 MC and segmental instability is unclear. This study sought to clarify the role of mechanical abnormalities in type 1 MC.MethodReview of magnetic resonance images obtained for 727 patients over a 1-year period at our institution revealed 161 cases of type 1 MC. In 86 of these, the following indicators of mechanical abnormality could be evaluated on dynamic radiographs: segmental scoliosis (> 5°), forward slippage (> 1%), and posterior disc opening in flexion. Patients with one or more of these abnormalities were allocated to a mechanical group (n = 62, 70%) and those with no abnormality to a non-mechanical group (n = 26, 30%). The Pfirrmann grade of disc degeneration at the affected level was compared between the groups.ResultsSegmental scoliosis, slippage, and posterior opening was observed in 34, 21 and 37 cases, respectively. Severe disc degeneration (grade IV or V) was present in 43 cases (69%) in the mechanical group and in 12 cases (46%) in the non-mechanical group; the difference was statistically significant (p = 0.04).ConclusionWe propose that there are mechanical and non-mechanical variants of type 1 MC.

Type 2 sclerotic Modic change affect fusion result in patients undergoing PLIF with pedicle screw instrumentation: a retrospective study

Background Bony fusion rate was significantly lower in patients with type 3 Modic change than patients with normal endplates. It is not known whether there are relevant differences in fusion efficiency among patients with type 2 sclerotic Modic change or non-sclerotic Modic change, or no Modic change. Methods A retrospective study contained 196 lumbar segments in 123 subjects undergoing posterior lumbar interbody fusion (PLIF) with pedicle screw instrumentation (PSI) to assess the effect of type 2 sclerotic Modic change on fusion efficiency. These endplates were allocated into groups A, B, and C, according to their Modic changes. Group A had endplates with type 2 Modic change and endplate sclerosis. Group B had type 2 Modic change without endplate sclerosis. Group C had neither Modic change nor endplate sclerosis. The presence of Modic change was determined by magnetic resonance imaging (MRI). Endplate sclerosis in type 2 Modic change was detected by computed tomography (CT) before the operation. We collected CT data 3 months to more than 24 months after operation in patients to assess bony fusion. Results Incidences of bony fusion were 58.8% in group A, 95.0% in group B, 94.3% in group C. The bony fusion rate was significantly lower in group A than in either group B or C. There was no significant difference between groups B and C. Thus, endplates with type 2 sclerotic Modic change had a lower fusion rate in patients undergoing PLIF with PSI. Conclusion Type 2 sclerotic Modic change could be an important factor that affects solid bony fusion in patients undergoing PLIF with PSI. CT may help diagnose endplate sclerosis in patients with type 2 change and inform the choice of the best site for spinal fusion.

Development and validation of a nomogram predicting the risk of recurrent lumbar disk herniation within 6 months after percutaneous endoscopic lumbar discectomy

Objective To develop and validate a nomogram useful in predicting recurrent lumbar disk herniation (rLDH) within 6 months after percutaneous endoscopic lumbar discectomy (PELD). Methods Information on patients’ lumbar disk herniation (LDH) between January 2018 and May 2019 in addition to 26 other features was collected from the authors’ hospital. The least absolute shrinkage and selection operator (LASSO) method was used to select the most important risk factors. Moreover, a nomogram was used to build a prediction model using the risk factors selected from LASSO regression. The concordance index (C-index), the receiver operating characteristic (ROC) curve, and calibration curve were used to assess the performance of the model. Finally, clinical usefulness of the nomogram was analyzed using the decision curve and bootstrapping used for internal validation. Results Totally, 352 LDH patients were included into this study. Thirty-two patients had recurrence within 6 months while 320 showed no recurrence. Four potential factors, the course of disease, Pfirrmann grade, Modic change, and migration grade, were selected according to the LASSO regression model. Additionally, the C-index of the prediction nomogram was 0.813 (95% CI, 0.726-0.900) and the area under receiver operating characteristic curve (AUC) value was 0.798 while the interval bootstrapping validation C-index was 0.743. Hence, the nomogram might be a good predictive model. Conclusion Each variable, the course of disease, Pfirrmann grade, Modic change, and migration grade in the nomogram had a quantitatively corresponding risk score, which can be used in predicting the overall recurrence rate of rLDH within 6 months.

Biomechanical Comparison of Vertebral Augmentation and Cement Discoplasty for the Treatment of Symptomatic Schmorl’s Node Combined With Modic Change: Finite Element Analyses

Study design: Finite element simulation study.Objective: To compare the biomechanical effects of percutaneous vertebral augmentation (PVA) and percutaneous cement discoplasty (PCD) in patients with symptomatic Schmorl’s node combined with Modic change.Methods: CT data from a single patient was assembled into finite element models, from which we constructed four distinct surgical models, including PVA-ideal, PVA-nonideal, PCD-ideal, and PCD-nonideal, to compare the stress and strain differences of parapodular tissues.Results: The validity of our model was confirmed. PVA-ideal model showed a moderate reduction in the stress peak of the Schmorl’s node (0.48 vs. 0.81–0.89 Mpa) in the erect position. In the PCD-ideal model, the stress peak of the Schmorl’s node increased significantly when the spine was moved toward the lesion (3.99Mpa). Both PVA-ideal and PCD-ideal models showed global strain inhibition at the Schmorl’s node and BMEZ, which was attenuated in the non-ideal models. The PCD-ideal model significantly reduced segmental ROM (-76.8% to -59.3%) and significantly increases endplate stress (up to 220.8%), with no such effects seen in the PVA-ideal model.Conclusions: Both PVA-ideal and PCD-ideal models facilitated a more stable parapodular biomechanical microenvironment. The PVA-ideal model yielded minimal stress disturbance on the augmented or adjacent vertebral endplate but offered no improvement to segment stability. The PCD-ideal model provides adequate segment stability, but also carries a greater risk for adjacent vertebral fracture. As nonideal implementations of both surgeries can result in poor biomechanical outcomes, the surgical indications of PVA or PCD need to be carefully selected.

Type 2 Sclerotic Modic Change Affect Fusion Result in Patients Undergoing PLIF With Pedicle Screw Instrumentation: A Retrospective Study

BackgroundBony fusion rate was significantly lower in patients with type 3 Modic change than patients with normal endplates. It is not known whether there are relevant differences in fusion efficiency among patients with type 2 sclerotic Modic change or non sclerotic Modic change, or no Modic change.MethodsA retrospective study contained 208 lumbar segments in 131 subjects undergoing posterior lumbar interbody fusion (PLIF) with pedicle screw instrumentation (PSI) to assess the effect of type 2 sclerotic Modic change on fusion efficiency. These endplates were allocated into groups A, B, and C, according to their Modic changes. Group A had endplates with type 2 Modic change and endplate sclerosis. Group B had type 2 Modic change without endplate sclerosis. Group C had neither Modic change nor endplate sclerosis. The presence of Modic change was determined by magnetic resonance imaging (MRI). Endplate sclerosis in type 2 Modic change was detected by computed tomography (CT). We collected CT data 3 months till more than 24 months after operation in patients to assess bony fusion.ResultsIncidences of bony fusion were 55.3% in group A, 95.1% in group B, 93.8% in group C. The bony fusion rate was significantly lower in group A than in either group B or C. There was no significant difference between groups B and C. Thus, endplates with type 2 sclerotic Modic change had a lower fusion rate in patients undergoing PLIF with PSI.ConclusionType 2 sclerotic Modic change could be an important factor that affects solid bony fusion in patients undergoing PLIF with PSI. CT may help diagnose endplate sclerosis in patients with type 2 change and inform the choice of best site for spinal fusion.