Vertical Relationship Ratio (VRR): A High Reliability and Accuracy Radiographic Measurement for Basilar Invagination in Rheumatoid Arthritis.

BACKGROUND Previous radiographic measurements for diagnosis of a basilar invagination or impression (BI) in rheumatoid arthritis (RA) were used as reference values based on anatomical reference distances. Due to the obscured anatomical landmarks, our group proposed a new radiographic measurement based on anatomic ratios to identify BI. MATERIAL AND METHODS The vertical relationship ratio (VRR) was developed and evaluated. The VRR is the relationship between the distance obtained with the modified Ranawat method and the C3 vertebral body height. VRR was used to assess its ability to distinguish BI in 3 patient groups (28 RA with BI, 37 RA without BI, and 56 non-RA patients). The intra- and inter-observer reliability, the sensitivities, and specificities of all measurements were analyzed. The cutoff value of VRR measurement was calculated by using the receiver operating characteristic (ROC) curve. RESULTS The VRR measurement showed excellent intra- and inter-observer reliabilities. The VRR could significantly distinguish RA patients with BI from RA patients without BI. The mean VRR of RA patients with BI (1.82±0.20) was less than for the non-RA patients (2.26±0.19) and the RA patients without BI (2.24±0.19). The cutoff value of VRR from the ROC curve was below 2.025. Its sensitivity was 92.85%, specificity was 97.85%, positive predictive value was 92.86%, and negative predictive value was 97.84%. CONCLUSIONS VRR has excellent intra-/inter-observer reliability and can distinguished BI in RA patients. We recommend using VRR in preference to the other available methods for assessment and screening BI in rheumatoid arthritis.

An effectiveness and economic analyses of tricalcium phosphate combined with iliac bone graft versus RhBMP-2 in single-level XLIF surgery in Thailand.

STUDY DESIGN: Retrospective study. OBJECTIVES: To perform effectiveness and economic analyses using data from a retrospective study of patients who underwent XLIF surgery using tricalcium phosphate combined with iliac bone graft (TCP + IBG) or BMP-2 in Thailand. METHODS: Data were collected from retrospective review of the medical charts and the spine registry of Siriraj Hospital, Bangkok, Thailand. The patients were divided into two groups (TCP + IBG group and BMP-2 group). Demographic, perioperative data, radiographic, clinical results, and quality of life related to health were collected and analyzed at 2-year follow-up. All economic data were collected during the perioperative period and presented as total charge, bone graft, implant/instrumentation, operative service, surgical supply, transfusion, medication, anesthesia, laboratory, and physical therapy. RESULTS: Twenty-five TCP + IBG and 30 BMP-2 patients with spondylolisthesis and spinal stenosis as primary diagnosis were included. There were no significant differences in all demographic parameters (gender, age, underlying disease, diagnosis, and level of spine) between these two groups. During the perioperative period, the TCP + IBG group had more mean blood loss and more postoperative complications compared to the BMP-2 group. At 2 years of follow-up, there were no significant differences between the radiographic and clinical outcomes of the TCP + IBG and BMP-2 groups. The fusion rate for TCP + IBG and BMP-2 at 2 years of follow-up was 80% and 96.7%, respectively, and no statistically significant differences were observed. All clinical outcomes (Utility, Oswestry Disability Index, and EuroQol Visual Analog Scale) at 2-year follow-up improved significantly compared to preoperative outcomes, but there were no significant differences between the TCP + IBG and BMP-2 groups, either at preoperatively or at 2-year follow-up. The total charge of TCP + IBG was statistically significantly lower than that of BMP-2. Furthermore, the charges of TCP + IBG and BMP-2 during the perioperative period in Thailand were up to three times less than those in the United States. CONCLUSIONS: Using TCP + IBG as a standalone bone substitution for XLIF surgery with additional posterior instrumentation resulted in significantly lower direct medical charge compared to those using BMP-2 in the perioperative period. However, we could not detect a difference in the long-term radiographic and clinical outcomes of patients with TCP + IBG and BMP-2. These suggest that TCP + IBG may be a valuable alterative bone graft, especially in low- and middle-income countries.

Lateral lumbar interbody fusion (LLIF) reduces total lifetime cost compared with posterior lumbar interbody fusion (PLIF) for single-level lumbar spinal fusion surgery: a cost-utility analysis in Thailand.

BACKGROUND: Lumbar interbody fusion techniques treat degenerative lumbar diseases effectively. Minimally invasive lateral lumbar interbody fusion (LLIF) decreases soft tissue disruption and accelerates recovery better than standard open posterior lumbar interbody fusion (PLIF). However, the material cost of LLIF is high, especially in Thailand. The cost-effectiveness of LLIF and PLIF in developing countries is unclear. This study compared the cost-utility and clinical outcomes of LLIF and PLIF in Thailand. METHODS: Data from patients with lumbar spondylosis who underwent single-level LLIF and PLIF between 2014 and 2020 were retrospectively reviewed. Preoperative and 1-year follow-up EuroQol-5D-5L and healthcare costs were collected. A cost-utility analysis with a lifetime time horizon was performed using a societal perspective. Outcomes are reported as the incremental cost-effectiveness ratio (ICER) and quality-adjusted life-year (QALY) gained. A Thai willingness-to-pay threshold of 5003 US dollars (USD) per QALY gained was used. RESULTS: The 136 enrolled patients had a mean age of 62.26 ± 11.66 years. Fifty-nine patients underwent LLIF, while 77 underwent PLIF. The PLIF group experienced greater estimated blood loss (458.96 vs 167.03 ml; P < 0.001), but the LLIF group had a longer operative time (222.80 vs 194.62 min; P = 0.007). One year postoperatively, the groups' Oswestry Disability Index and EuroQol-Visual Analog Scale scores were improved without statistical significance. The PLIF group had a significantly better utility score than the LLIF group (0.89 vs 0.84; P = 0.023). LLIF's total lifetime cost was less than that of PLIF (30,124 and 33,003 USD). Relative to PLIF, LLIF was not cost-effective according to the Thai willingness-to-pay threshold, with an ICER of 19,359 USD per QALY gained. CONCLUSIONS: LLIF demonstrated lower total lifetime cost from a societal perspective. Regard to our data, at the 1-year follow-up, the improvement in patient quality of life was less with LLIF than with PLIF. Additionally, economic evaluation modeling based on the context of Thailand showed that LLIF was not cost-effective compared with PLIF. A strategy that facilitates the selection of patients for LLIF is required to optimize patient benefits.