Transarterial Embolization for Refractory Non-Cervical-Origin Interscapular Pain Following Ultrasound-Guided Injection: A Retrospective Feasibility Study

Abstract

Objective: Chronic non-cervical-origin interscapular pain remains challenging to treat when refractory to conservative management and ultrasound-guided injections. This retrospective feasibility study aimed to assess the feasibility, procedural practicality, safety, and preliminary clinical outcomes of transarterial embolization (TAE) as a salvage therapy in this patient population. Methods: This single-center retrospective study included 20 patients with chronic interscapular pain (Numeric Rating Scale [NRS] score ≥5 for >3 months) who initially underwent ultrasound-guided injection therapy. Patients who experienced inadequate pain relief after 3 months (n = 10) proceeded to TAE, while the remaining 10 patients with sufficient relief formed the comparison group. TAE primarily targeted the transverse cervical artery using imipenem/cilastatin sodium as the embolic agent. Pain outcomes were assessed using NRS scores at 1, 3, and 6 months post-procedure. The primary outcome was pain reduction (≥50% decrease in NRS score), with secondary outcomes including technical success, medication use, and safety assessment. Results: The mean baseline NRS score for all patients was 6.5 ± 1.4, which decreased to 3.4 ± 2.0 at 1 month and 3.9 ± 2.5 at 3 months post-injection (p < 0.001). In the TAE group, the NRS score decreased from 7.4 ± 1.4 to 5.1 ± 1.1 at 1 month and 6.0 ± 1.4 at 3 months, indicating inadequate pain relief. In contrast, the injection-only group showed significant improvement, with NRS scores decreasing from 5.6 ± 0.5 to 1.6 ± 0.5 at 1 month and 1.7 ± 0.7 at 3 months (p < 0.001). The reduction in NRS scores was significantly less in the TAE group compared with the injection-only group (-2.2 vs. -4.0 and -28.7% vs. -71.4% at 1 month; -1.4 vs. -3.9 and -18.2% vs. -69.7% at 3 months; all p ≤ 0.001). Following TAE, the mean NRS score further decreased to 2.1 ± 0.7, 2.0 ± 1.1, and 1.9 ± 1.2 at 1, 3, and 6 months, respectively (p < 0.001), with clinical success rates of 90%, 100%, and 90% at these respective time points. At the final follow-up, the percentage of NRS score reduction was comparable between the TAE and injection-only groups (-74.8% vs. -69.7%, p = 0.397). No severe or life-threatening adverse events were observed; only self-limited adverse events were reported. Conclusions: In this retrospective feasibility study, TAE appeared safe and effective as a salvage therapy for patients with refractory non-cervical-origin interscapular pain unresponsive to injection therapy. Further prospective, randomized studies are needed to validate these findings, refine patient selection criteria, and optimize treatment outcomes.

Keywords: chronic musculoskeletal pain; imipenem/cilastatin sodium; interscapular pain; transarterial embolization; ultrasound-guided injection.

Figure 1

Flow diagram of patient selection, enrollment, and follow-up.

Figure 2

Digital subtraction angiography of the deep branch of the left transverse cervical artery in a 56-year-old woman with refractory interscapular pain. (A) Pre-embolization image shows abnormal neovascularization in the interscapular area (arrows). (B) Post-embolization image demonstrates disappearance of abnormal blush in the corresponding area (arrows). This patient experienced a decrease in NRS score from 6 to 2 at 6-month follow-up (67% reduction).

Figure 3

Mean numerical rating scale (NRS) scores over time in patients receiving ultrasound-guided injection only (n = 10) and in patients who underwent injection followed by subsequent transarterial embolization (TAE) (n = 10). The red arrow indicates the timing of TAE in the latter group. Baseline, 1M, and 3M denote 1 and 3 months after injection; +1M, +3M, and +6M denote 1, 3, and 6 months after TAE. M = month. Patients with inadequate response to injection therapy demonstrated significant pain reduction after TAE, which was sustained for up to 6 months.