TARGETING DUAL PATHWAYS IN REFRACTORY COCCYDYNIA: A COMPARATIVE STUDY OF GANGLION IMPAR BLOCK ALONE VERSUS COMBINED WITH PERICOCCYGEAL INJECTION

Study Design and Population This retrospective study compared the effects of GIB alone versus GIB combined with pericoccygeal injection in coccydynia patients treated at the Pain Clinic of Kanuni Sultan Süleyman Training and Research Hospital. The study cohort was drawn from patients with a confirmed diagnosis of coccydynia persistent for at least 3 months as determined by history, clinical examination, and radiological imaging, who had undergone either GIB or GIB with pericoccygeal injection, and had complete medical records available for review between June 2022 and June 2024. Patients having a recent intervention (in the past 6 months), morbid obesity (BMI > 35 kg/m²), severe comorbidities, skin infections, bleeding disorders, pregnancy, or having incomplete records were excluded. A total of 60 patients aged 18-65 years who underwent either GIB or GIB with pericoccygeal injection were included. The sample size was determined using a power analysis (effect size: 0.84, power: 80%, error margin: 5%), based on previously published studies reporting significant differences in pain and functional outcomes following ganglion impar block interventions. Accordingly, a minimum of 30 patients per group was required, and a total of 60 patients were enrolled.

Intervention A standard procedure was applied to all patients by the same pain medicine specialist with over 5 years of experience, in a sterile operating room under fluoroscopic guidance and monitored conditions. The patients underwent noninvasive blood pressure monitoring, pulse oximetry, and a five-lead electrocardiogram [ECG], and intravenous access was established in the forearm before positioning for the intervention. The position used during the intervention was the prone position, with a pillow placed under the belly. The procedure area was disinfected with povidone-iodine and covered with a sterile drape. Anterior-posterior (AP) imaging was first performed with a C-arm scopy device, which was then placed in the lateral position.

The ganglion impar was accessed with a Quincke spinal needle, transsacrococcygeally (from between the first and second coccygeal vertebrae if sacrococcygeal access could not be achieved). Then, 1 mL of non-ionic contrast medium was administered, and fluoroscopic anterior-posterior and lateral imaging was performed to confirm the appropriate spread of contrast. After this confirmation, 2 mL of 0.5% bupivacaine, 2 mL of saline, and 40 mg of methylprednisolone acetate were injected.

In the combination therapy group who underwent pericoccygeal injection in addition to impar block, following the same procedure, 5 mL of 0.25% bupivacaine and 20 mg of methylprednisolone were injected into the posterior pericoccygeal region while the needle was withdrawn, thus also targeting blockade of the anococcygeal nerve.

After the procedure, all patients were monitored and observed for at least two hours. Patients who had no additional complaints during follow-up visits were discharged.