Development of a New Therapy-Oriented Classification of Intervertebral Vacuum Phenomenon With Evaluation of Intra- and Interobserver Reliabilities

Abstract

Study Design: Diagnostic study, level of evidence III. Objectives: Low back pain is a common cause of disability among elderly patients. Percutaneous discoplasty has been developed as a tool to treat degenerative disease when conservative management is not successful. Indications for this procedure include low back pain and the presence of vacuum phenomenon. The objective of this study was to describe a new classification of vacuum phenomenon based on computed tomography scan in order to improve the indications for percutaneous discoplasty. Methods: We developed a classification of vacuum phenomenon based on computed tomography scan images. We describe 3 types of vacuum based on the relationship between vacuum and the superior/inferior endplates and 2 subtypes based on the presence of significant subchondral sclerosis. A validation study was conducted selecting 10 orthopedic residents with spine surgery training to analyze 25 vacuum scenarios. Inter- and intraobserver reliabilities were assessed through the Fleiss’s and Cohen’s kappa statistics, respectively. Results: The overall Fleiss’s κ value for interobserver reliability was 0.85 (95% CI 0.82-0.86) in the first reading and 0.93 (95% CI 0.92-0.95) in the second reading. Cohen’s κ for intraobserver reliability was 0.88 (95% CI 0.77-0.99). Conclusion: The new classification has shown almost perfect inter- and intraobserver reliabilities for grading the vacuum phenomenon and could be an important tool to improve the indications for percutaneous cement discoplasty.

Testing the impact of discoplasty on the biomechanics of the intervertebral disc with simulated degeneration: An in vitro study

“…The importance of this parameter is unclear in the clinical practice. A recent study investigating the Vacuum Phenomenon (VP) impact for PCD indication concluded that the volume of vacuum could not be used as a proper indication for this surgery [36]. Moreover, during the PCD procedure, the patient position aims at enlarging the intervertebral space by reducing the segmental lordosis.…”

Critical Review of the State-of-the-Art on Lumbar Percutaneous Cement Discoplasty

“…The articles found included four prospective studies ( 9 , 16 – 18 ), one case study ( 19 ), two diagnostic studies ( 20 , 21 ), five retrospective studies ( 22 – 26 ), four biomechanical studies whose only three published ( 27 – 29 ). The four remaining publications were correspondence to the Editor articulated around two distinct conversations.…”

“…Two papers presented case studies ( 9 , 19 ). Camino-Willhuber et al focused on the development of a methodology to fine-tune the diagnosis of cases requiring PCD as a treatment ( 20 ). Eltes et al .…”

“…Pfirrmann’s scale evaluates the intervertebral disc degeneration stage; however PCD principally depends on VP and the surrounding tissue state. For this reason, surgery planning was refined to identify patients having the most suitable pathological condition of the disc and the endplates ( 20 ). A new classification of VP, established from Computed Tomography scans, identified four levels of VP based on the rate intervertebral vacuum/disc tissue and two sub-levels depending on the presence of subchondral stenosis.…”

Lateral Interbody Fusion for Hyperlordosis and Negative Sagittal Vertical Axis Because of Accordion Phenomenon

“…The accordion phenomenon is defined as the difference in the disc space observed on x-ray or computed tomography (CT) images taken in both standing and supine positions, which results in a discrepancy of local spinal alignment. Moreover, this phenomenon occurs in advanced degeneration of the intervertebral disc with vacuum phenomenon and is considered to cause mechanical low back pain 2,3 .…”