Proposal for a classification system of radiographic bone changes after cervical disc replacement.

BACKGROUND: The goal of this study is to propose a classification system with a common nomenclature for radiographic observations of periprosthetic bone changes following cTDR. METHODS: Aided by serial plain radiographs from recent cTDR cases (34 patients; 44 devices), a panel of experts assembled for the purpose of creating a classification system to aid in reproducibly and accurately identifying bony changes and assessing cTDR radiographic appearance. Subdividing the superior and inferior vertebral bodies into 3 equal sections, observed bone loss such as endplate rounding, cystic erosion adjacent to the endplate, and cystic erosion not adjacent to the endplate, is recorded. Determining if bone loss is progressive, based on serial radiographs, and estimating severity of bone loss (measured by the percentage of end plate involved) is recorded. Additional relevant bony changes and device observations include radiolucent lines, heterotopic ossification, vertebral body olisthesis, loss of core implant height, and presence of device migration, and subsidence. RESULTS: Serial radiographs from 19 patients (25 devices) implanted with a variety of cTDR designs were assessed by 6 investigators including clinicians and scientists experienced in cTDR or appendicular skeleton joint replacement. The overall agreement of assessments ranged from 49.9% (95% bootstrap confidence interval 45.1-73.1%) to 94.7% (95% CI 86.9-100.0%). There was reasonable agreement on the presence or absence of bone loss or radiolucencies (range: 58.4% (95% CI 51.5-82.7%) to 94.7% (95% CI 86.9-100.0%), as well as in the progression of radiolucent lines (82.9% (95% CI 74.4-96.5%)). CONCLUSIONS: The novel classification system proposed demonstrated good concordance among experienced investigators in this field and represents a useful advancement for improving reporting in cTDR studies.

A real-world analysis of hybrid CDA and ACDF compared to multilevel ACDF.

BACKGROUND: Multilevel anterior cervical discectomy and fusion (mACDF) is the gold standard for multilevel spinal disease; although safe and effective, mACDF can limit regular spinal motion and contribute to adjacent segment disease (ASD). Hybrid surgery, composed of ACDF and cervical disc arthroplasty, has the potential to reduce ASD by retaining spinal mobility. This study examined the safety of hybrid surgery by utilizing administrative claims data to compare real-world rates of subsequent surgery and post-procedural hospitalization within populations of patients undergoing hybrid surgery versus mACDF for multilevel spinal disease. METHODS: This observational, retrospective analysis used the MarketScan Commercial and Medicare Database from July 2013 through June 2020. Propensity score matched cohorts of patients who received hybrid surgery or mACDF were established based on the presence of spinal surgery procedure codes in the claims data and followed over a variable post-period. Rates of subsequent surgery and post-procedural hospitalization (30- and 90-day) were compared between hybrid surgery and mACDF cohorts. RESULTS: A total of 430 hybrid surgery patients and 2,136 mACDF patients qualified for the study; average follow-up was approximately 2 years. Similar rates of subsequent surgery (Hybrid: 1.9 surgeries/100 patient-years; mACDF: 1.8 surgeries/100 patient-years) were observed for the two cohorts. Hospitalization rates were also similar across cohorts at 30 days post-procedure (Hybrid: 0.67% hospitalized/patient-year; mACDF: 0.87% hospitalized/patient-year). At 90 days post-procedure, hybrid surgery patients had slightly lower rates of hospitalization compared to mACDF patients (0.23% versus 0.42% hospitalized/patient-year; p < 0.05). CONCLUSIONS: Findings of this real-world, retrospective cohort study confirm prior reports indicating that hybrid surgery is a safe and effective intervention for multilevel spinal disease which demonstrates non-inferiority in relation to the current gold standard mACDF. The use of administrative claims data in this analysis provides a unique perspective allowing the inclusion of a larger, more generalizable population has historically been reported on in small cohort studies.