Feasibility of a novel augmented reality overlay for cervical screw placement in phantom spine models

Methods@#AR technology that uses a fiducial-less registration system was tested in a preclinical cervical spine phantom model study for accuracy during spinal screw placement. A three-dimensional reconstruction of the spine along with trajectory lines was superimposed onto the phantom model using an AR headset. Participants used the AR system to guide screw placement, and post-instrumentation scans were compared for accuracy assessment. @*Results@#Twelve cervical screws were placed under AR guidance. All screws were placed in an acceptable anatomic position. The average distance error for the insertion point was 2.73±0.55 mm, whereas that for the endpoint was 2.71±0.69 mm. The average trajectory angle error for all insertions was 2.69°±0.59°. @*Conclusions@#This feasibility study describes a novel registration approach that superimposes spinal anatomy and trajectories onto the surgeon’s real-world view of the spine. These results demonstrate reasonable accuracy in the preclinical model. The results of this study demonstrate that this technology can assist with accurate screw placement. Further investigation using cadaveric and clinical models is warranted.

Antineutrophil Cytoplasmic Antibody Positivity Is Associated with Vascular Involvement in Behçet’s Disease

Purpose@#We investigated whether antineutrophil cytoplasmic antibody (ANCA) positivity is associated with vascular manifestations at diagnosis of Behçet's disease (BD) and poor outcomes during follow-up. @*Materials and Methods@#We retrospectively reviewed the medical records of 1060 patients with BD. Among them, 808 patients could be diagnosed with BD based on the revised version of the International Criteria for Behçet's Disease (ICBD) in 2014 (2014 ICBD criteria) and 588 patients could be diagnosed with BD based on the International Study Group (ISG) criteria proposed in 1990 (1990 ISG criteria). We examined the sites and patterns of vascular involvement in the BD patients at diagnosis and evaluated adverse outcomes during follow up, such as all-cause mortality, acute coronary syndrome, and deep vein thrombosis. @*Results@#Among the 808 patients with BD based on the 2014 ICBD criteria, the rate of ANCA positivity at diagnosis was 2.2%. ANCA-positive BD patients exhibited a higher frequency of overall vascular manifestations (22.2% vs. 6.1%) and higher frequencies of vascular involvement in the upper extremities and visceral arteries than ANCA-negative BD patients (5.6% vs. 0.1% and 5.6% vs. 0.1%). Among the 588 BD patients based on the 1990 ISG criteria, similarly, ANCA-positive BD patients exhibited a higher frequency of vascular manifestations than ANCA-negative BD patients. ANCA positivity, however, did not seem to be associated with poor outcomes in BD patients during follow up. @*Conclusion@#ANCA positivity in BD patients was found to be associated with cross-sectional vascular involvement in the upper extremities and visceral arteries at diagnosis but was not predictive of poor outcomes during follow-up.

Rituximab Biosimilar Prevents Poor Outcomes of Microscopic Polyangiitis and Granulomatosis with Polyangiitis as Effectively as Rituximab Originator

Purpose@#There has been no extensive study to compare the efficacy between rituximab originator (Mabthera®) and its biosimilar (Truxima®) for microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA). Here, we investigated the clinical effects of rituximab on poor outcomes of MPA and GPA in Korean patients, and compared those between Mabthera® and Truxima®. @*Materials and Methods@#We retrospectively reviewed the medical records of a total of 139 patients, including 97 MPA patients and 42 GPA patients. At diagnosis, antineutrophil cytoplasmic antibody positivity and comorbidities were assessed. During follow-up, all-cause mortality, relapse, end-stage renal disease, cerebrovascular accident and acute coronary syndrome were evaluated as poor outcomes. In this study, rituximab was used as either Mabthera® or Truxima®. @*Results@#The median age at diagnosis was 60.1 years and 46 patients were men (97 MPA and 42 GPA patients). Among poor outcomes, patients receiving rituximab exhibited a significantly lower cumulative relapse-free survival rate compared to those not receiving rituximab (p=0.002). Nevertheless, rituximab use did not make any difference in other poor outcomes of MPA and GPA except for relapse, which might be a rebuttal to the fact that rituximab use after relapse eventually led to better prognosis. There were no significant differences in variables at diagnosis and during follow-up between patients receiving Mabthera® and those receiving Truxima®. Patients receiving Truxima® exhibited a similar pattern of the cumulative survival rates of each poor outcome to those receiving Mabthera®. @*Conclusion@#Truxima® prevents poor outcomes of MPA and GPA as effectively as does Mabthera®.