Peer-reviewedCC BY 4.0European Radiology13 May 2026

CT-guided injection in coccydynia: outcome prediction using MRI findings and CT-injection characteristics

Georg Wilhelm Kajdi¹
Thomas Marth^1,2
Christoph Germann¹
Mazda Farshad³
Reto Sutter¹

¹Department of Radiology, Balgrist University Hospital, Faculty of Medicine, University of Zurich, Zurich, Switzerland
²Swiss Center for Musculoskeletal Imaging, Balgrist Campus AG, Zurich, Switzerland
³Department of Orthopedics, Balgrist University Hospital, Faculty of Medicine, University of Zurich, Zurich, Switzerland

Abstract

Objectives: To analyze pain relief for chronic coccydynia after CT-guided, pericoccygeal ropivacaine and triamcinolone injection over time and to investigate possible imaging predictors of successful and maintained pain relief.

Materials and methods: In this retrospective study, chronic coccydynia patients receiving CT-guided pericoccygeal injections with ropivacaine and triamcinolone were assessed for pain relief post-injection, using a numeric rating scale (NRS, 0–10) and percentage pain reduction (PPR, %). Patients were followed up until pain recurrence. Two radiologists assessed MRI findings prior to, and contrast distribution during CT injection. Imaging predictors for successful pain relief at 1 month (PPR ≥ 50%) combined with maintained pain relief for at least 3 months post-injection were investigated using logistic regression analysis.

Results: 63 patients (mean age 44.6 ± 12.5 years) were evaluated. Average pain dropped from initially 6.3 to 3.0 (average PPR 53.2 ± 37.5%) 15 min post-injection, and to 2.9 (average PPR 55.2 ± 41.4%) one month post-injection (all p < 0.001). One month post-injection, 41 patients (65%) reported PPR ≥ 50%. Pain relief persisted on average for 6 months. Three months post-injection, 32/63 patients (50.8%) reported maintained pain relief. Fluid-sensitive sequence (FSS)-hyperintensity of the sacro-/intercoccygeal synchondrosis, coccyx subluxation and a bony spicule were the only significant predictors (odds ratios: 3.5–5.1) of successful and maintained pain relief (all p ≤ 0.031).

Conclusion: CT-guided pericoccygeal injection with ropivacaine and triamcinolone allowed successful pain relief in 65% of chronic coccydynia patients, with a PPR of 55% and persistence of 26 weeks on average. Odds of successful and maintained pain relief increased with the presence of a bony spicule, subluxation and FSS-hyperintensity of the synchondrosis.

Key Points: Question Imaging predictors of successful pain relief in chronic coccydynia patients receiving pericoccygeal ropivacaine and triamcinolone injections are unknown.

Findings A bony spicule, subluxation, and sacro-/intercoccygeal fluid-sensitive sequence hyperintensity on MRI were significant predictors of successful pain relief for ≥ 3 months. CT-contrast distribution did not influence pain relief.

Clinical relevance CT-guided pericoccygeal injections with ropivacaine and triamcinolone offer successful pain relief in chronic coccydynia; the presence of a bony spicule, subluxation, and sacro-/intercoccygeal fluid-sensitive sequence hyperintensity was predictive of pain relief.

Graphical Abstract:

Intravitreal Anti-vascular Endothelial Growth Factor Injection Practices Among Indonesian Vitreoretinal Specialists: Findings From a 2021 National Survey
Andrea Silitonga, Hanna Tabita Hasianna Silitonga, Rova Virgana +4
Cureus16 Oct 2026Peer-reviewedCC BYFull textGeneral medicineEurope PMC
Spondylodiscitis in a tuberculosis-endemic setting in Somalia: epidemiological, clinical, radiological, and outcome findings from a retrospective study
Hussein Salad Yusuf, Abdirisak Ali Abukar, Mohamed Said Adan +6
Frontiers in tuberculosis24 Oct 2026Peer-reviewedCC BYFull textGeneral medicineEurope PMC
Early hematoma expansion provides incremental prognostic information beyond admission characteristics for 6-month functional outcome after adult traumatic brain injury
Yinghao Yang, Changtao Liu, Rongjie Wu +3
Frontiers in neurology16 Oct 2026Peer-reviewedCC BYFull textNeurologyEurope PMC
Clinical and Laboratory Characteristics of Fabry Disease in Children and Adults: A Focus on Early Kidney Findings
Okan Akacı, Sevil Yıldız, Nimet Aktaş
Journal of clinical medicine25 Sep 2026Peer-reviewedCC BYFull textGeneral medicineEurope PMC
P-wave characteristics in Bayés syndrome predict feasibility of anterior mitral line ablation: The Left Anterior Bayés-Derived Mitral Linear Ablation Outcome and Conduction score
Suguru Nishiuchi, Hirohiko Kohjitani, Kohki Nakamura +8
Heart rhythm O220 Jul 2026Peer-reviewedCC BY-NC-NDFull textCardiovascular medicineEurope PMC

Cite

BibTeX RIS

BibTeX

@article{kajdi2026ctguided,
  title = {{CT-guided injection in coccydynia: outcome prediction using MRI findings and CT-injection characteristics}},
  author = {Georg Wilhelm Kajdi and Thomas Marth and Christoph Germann and Mazda Farshad and Reto Sutter},
  journal = {European Radiology},
  year = {2026},
  month = may,
  doi = {10.1007/s00330-026-12615-3},
  url = {https://doi.org/10.1007/s00330-026-12615-3},
  note = {CC BY 4.0},
}

RIS

TY  - JOUR
TI  - CT-guided injection in coccydynia: outcome prediction using MRI findings and CT-injection characteristics
AU  - Georg Wilhelm Kajdi
AU  - Thomas Marth
AU  - Christoph Germann
AU  - Mazda Farshad
AU  - Reto Sutter
PY  - 2026
DA  - 2026/05/13
JO  - European Radiology
DO  - 10.1007/s00330-026-12615-3
UR  - https://doi.org/10.1007/s00330-026-12615-3
AB  - Objectives: To analyze pain relief for chronic coccydynia after CT-guided, pericoccygeal ropivacaine and triamcinolone injection over time and to investigate possible imaging predictors of successful and maintained pain relief.  Materials and methods: In this retrospective study, chronic coccydynia patients receiving CT-guided pericoccygeal injections with ropivacaine and triamcinolone were assessed for pain relief post-injection, using a numeric rating scale (NRS, 0–10) and percentage pain reduction (PPR, %). Patients were followed up until pain recurrence. Two radiologists assessed MRI findings prior to, and contrast distribution during CT injection. Imaging predictors for successful pain relief at 1 month (PPR ≥ 50%) combined with maintained pain relief for at least 3 months post-injection were investigated using logistic regression analysis.  Results: 63 patients (mean age 44.6 ± 12.5 years) were evaluated. Average pain dropped from initially 6.3 to 3.0 (average PPR 53.2 ± 37.5%) 15 min post-injection, and to 2.9 (average PPR 55.2 ± 41.4%) one month post-injection (all p < 0.001). One month post-injection, 41 patients (65%) reported PPR ≥ 50%. Pain relief persisted on average for 6 months. Three months post-injection, 32/63 patients (50.8%) reported maintained pain relief. Fluid-sensitive sequence (FSS)-hyperintensity of the sacro-/intercoccygeal synchondrosis, coccyx subluxation and a bony spicule were the only significant predictors (odds ratios: 3.5–5.1) of successful and maintained pain relief (all p ≤ 0.031).  Conclusion: CT-guided pericoccygeal injection with ropivacaine and triamcinolone allowed successful pain relief in 65% of chronic coccydynia patients, with a PPR of 55% and persistence of 26 weeks on average. Odds of successful and maintained pain relief increased with the presence of a bony spicule, subluxation and FSS-hyperintensity of the synchondrosis.  Key Points: Question Imaging predictors of successful pain relief in chronic coccydynia patients receiving pericoccygeal ropivacaine and triamcinolone injections are unknown.  Findings A bony spicule, subluxation, and sacro-/intercoccygeal fluid-sensitive sequence hyperintensity on MRI were significant predictors of successful pain relief for ≥ 3 months. CT-contrast distribution did not influence pain relief.  Clinical relevance CT-guided pericoccygeal injections with ropivacaine and triamcinolone offer successful pain relief in chronic coccydynia; the presence of a bony spicule, subluxation, and sacro-/intercoccygeal fluid-sensitive sequence hyperintensity was predictive of pain relief.  Graphical Abstract:
SN  - 0938-7994
SN  - 1432-1084
ER  -

Abstract

Related

Cite