Efficacy, Safety, and Sample Quality of Ultrasound‐Guided Synovial Needle Biopsy in Clinical Practice and Research: A Prospective Observational Study

Abstract

Objective To study the efficacy, tolerability, safety, and sampling variation of ultrasound (US)–guided synovial biopsies performed in clinical practice and research. Methods We included all patients who had a US‐guided synovial needle biopsy from November 2013 to January 2018. Patients were evaluated for procedure safety and tolerability. Usefulness of synovial biopsy was considered based on contribution for achieving the proposed aims. We analyzed samples for presence and quality of synovial tissue, synovitis score/grade, and pathotype. Variation across patients, samples, section levels, and sampling order was assessed. Results A total of 64 US‐guided synovial biopsies were performed (n = 52 in clinical practice, n = 12 in research). Patient tolerability (70% no/mild discomfort) was remarkably high. There was no significant aggravation of symptoms or US synovitis in the biopsied joint. Procedures were overall safe, with few minor, 2 moderate, and no major adverse events. Usefulness of US‐guided synovial biopsies was high, both in clinical practice (37% direct diagnostic impact, 100% positive/95% negative predictive values for infection) and in research (92% success). Synovial tissue was retrieved in 88% of biopsies, with a median of 75% gradable samples. There was significant variation in sample quality and synovitis features across patients and samples, but not between different section levels. Samples collected later in the procedure had a lower frequency of synovial tissue and were poorly concordant in pathotype with those collected earlier. Conclusion US‐guided synovial needle biopsy is an effective, safe, and well‐tolerated means to collect good quality synovial tissue for clinical and research purposes. Samples collected for different aims should be retrieved in parallel, rather than sequentially.

Synovial biopsies in clinical practice and research: current developments and perspectives

“…No other case of infectious arthritis was identified during follow-up, suggesting that synovial biopsy is reliable in excluding septic arthritis. The reliability of synovial biopsies to exclude infection in native joints has been replicated by others [18,19]. A causative organism is identified in less than half of patients who clinically have septic arthritis, and a synovial biopsy can be informative [20,23].…”

“…The majority of patients is somewhat or very likely to agree to another biopsy, with patient undergoing US-guided needle biopsies less willing than those undergoing US-guided portal and forceps biopsies or arthroscopic biopsies [16][17][18]. The willingness does not decline after a second biopsy [16].…”

“…Success rate, complications, and tolerability of arthroscopic and US-guided synovial biopsies[1,3,[13][14][15][16][17][18][19][20][21] Fewer studies have reported on US-guided port-and-forceps biopsies than arthroscopic and US-guided needle biopsies training model for ultrasound-guided synovial biopsy procedures in large and small joints leading to an educational video and recommendations (Moller et al, ongoing).…”

Ultrasound-Guided Synovial Biopsy: A Review

“…Regarding established RA, immunohistochemistry and immunofluorescence can also identify several pathotypes, whose various designations include diffuse, aggregate, lymphoid, granulomatous, follicular, myeloid, fibroblastic, and pauciimmune/fibroid synovitis (8,(37)(38)(39). Diffuse or myeloid synovitis affects 50-70% of patients, is associated with good responses to anti-TNF drugs, and has one of the most benign clinical phenotypes, where rheumatoid factors tend to be absent, CD68 + cells predominate, and there are few lymphocytes and no ectopic lymphoid structures (39)(40)(41).…”

“…Aggregate, follicular, or lymphoid synovitis is associated with more active disease and the presence of rheumatoid factor and tends to respond to anti-IL6 drugs. It affects 22-50% of patients and may comprise two subtypes, one associated with follicular dendritic cell networks or ectopic/tertiary lymphoid-like structures, and allegedly with worse outcome, and another which lacks those networks/features (37)(38)(39)(40). In follicular or lymphoid synovitis, B cell infiltrates and B cell markers predominate, while pauciimmune or fibroid synovitis is characterized by a fibroblast-rich landscape, overexpression of cellular and molecular markers of macrophages and fibroblasts, almost no immune cell infiltration, no associated rheumatoid factor, and a poor response to anti-TNF or anti-IL6 drugs (8,39); this subtype affects 20-30% of patients.…”