The role of periradicular infiltration in dorsal root ganglion stimulation for chronic neuropathic pain

Background Targeting the correct spinal level is essential in dorsal root ganglion (DRG) stimulation. Anatomical selection of the DRG alone is not ideal since the pain area is not necessarily confined to the borders of the dermatomes. This study aims to establish the role of periradicular infiltration therapy (PRT) in the preoperative assessment of the correct level for DRG stimulation performed under general anesthesia. Method We report a prospective study of 20 patients selected for DRG stimulation and submitted to a PRT for identification of the spinal level. Lead implantation for the stimulation trial occurred under general anesthesia: 19 patients experienced positive results and underwent implantation of the pulse generator. All patients suffered from chronic neuropathic pain unresponsive to best medical treatment. PRT levels were compared with the levels targeted with DRG leads. Patients were followed for up to 12 months; pain intensity and coverage of the painful area were assessed. Results In 12 patients, the trial leads were placed on the same level as previously tested positive by PRT. In 6 patients, leads were placed in the PRT target and additionally in adjacent spinal levels. In one case, the selected target for the trial diverged from the PRT target because of intense fibrosis in the chosen level. Coverage of the target area of at least 50% was achieved by two-thirds of the patients. For the six subjects with additional implanted leads as a consequence of the PRT results, 80% achieved a coverage of at least 50%. A total of 47.4% of the patients achieved sustained significant pain relief in the last follow-up. None of the patients needed a repeated surgery for implantation of additional leads. Conclusions PRT is a helpful tool to confirm the stimulation targets. A PRT preceding the stimulation trial is an additional opportunity to optimize the coverage of the target area with stimulation-induced paresthesia for patients operated under general anesthesia.

Radiation exposure of radiologists during different types of CT-guided interventions: an evaluation using dosimeters placed above and under lead protection

Background Computed tomography (CT) is widely used not only for diagnostic purposes but also for image guidance during different types of interventions. Therefore, radiation exposure of both patients and interventional radiologists remains a much-discussed topic. Purpose To quantify radiation exposure of interventional radiologists during multiple CT-guided interventions using dosimeters placed under and outside standard protective lead clothing. Material and Methods A total of 113 consecutive interventions covering three different types of procedures (grouped as periradicular infiltration therapy, biopsies, and drain placement) and performed using routine clinical protocols were prospectively analyzed. The interventions were performed by two radiologists of different experience levels with identically placed dosimeters outside and underneath their protective clothing. Personal doses (right hand, eye lens, thyroid gland, thorax, gonads) were cumulatively measured for each type of intervention and separately for the two radiologists. Results Personal dose was below the detection limit of the dosimeters during periradicular infiltration therapy. In the biopsy and drain placement groups, the highest dose was found for the right hand (maximum cumulative dose = 1.84 ± 1.30 mSv in 19 consecutive drain placements). Under the protective gear, exposure was only observed for drain placements performed by the less experienced radiologist (maximum = 0.05 ± 0.04 mSv for the eye lens). Conclusion Personal doses measured here were far below annual thresholds published by the International Commission on Radiological Protection. Therefore, performing multiple CT-guided interventions appears to be safe for interventional radiologists in terms of radiation exposure.

Periradicular Infiltration of the Cervical Spine: How New CT Scanner Techniques and Protocol Modifications Contribute to the Achievement of Low-Dose Interventions

Purpose CT-guided periradicular infiltration of the cervical spine is an effective symptomatic treatment in patients with radiculopathy-associated pain syndromes. This study evaluates the robustness and safety of a low-dose protocol on a CT scanner with iterative reconstruction software. Materials and Methods A total of 183 patients who underwent periradicular infiltration therapy of the cervical spine were included in this study. 82 interventions were performed on a new CT scanner with a new intervention protocol using an iterative reconstruction algorithm. Spot scanning was implemented for planning and a basic low-dose setup of 80 kVp and 5 mAs was established during intermittent fluoroscopy. The comparison group included 101 prior interventions on a scanner without iterative reconstruction. The dose-length product (DLP), number of acquisitions, pain reduction on a numeric analog scale, and protocol changes to achieve a safe intervention were recorded. Results The median DLP for the whole intervention was 24.3 mGy*cm in the comparison group and 1.8 mGy*cm in the study group. The median pain reduction was –3 in the study group and –2 in the comparison group. A 5 mAs increase in the tube current-time product was required in 5 patients of the study group. Conclusion Implementation of a new scanner and intervention protocol resulted in a 92.6 % dose reduction without a compromise in safety and pain relief. The dose needed here is more than 75 % lower than doses used for similar interventions in published studies. An increase of the tube current-time product was needed in only 6 % of interventions. Key Points: Citation Format

Periradicular infiltration of the lumbar spine: testing the robustness of an interventional ultra-low-dose protocol at different body mass index levels

Background Computed tomography (CT)-guided periradicular infiltration remains a frequent interventional procedure for treatment of low back pain. Purpose To present an interventional ultra-low-dose protocol for CT-guided periradicular infiltration therapy and assess its application at different body mass index (BMI) levels. Material and Methods Over a period of 14 months, 79 patients underwent 183 CT-guided interventions for single-site lumbar periradicular therapy using an ultra-low-dose protocol with a basic setup of 100 kV and 5 mAs. Procedures were performed via intermittent fluoroscopy. A retrospective review was performed to analyze the parameters tube current and tube voltage, dose-length product, and BMI. Results The interventional ultra-low-dose protocol allowed safe treatment of 91.1% of the patients without a need for adapting the protocol. In seven patients with a higher BMI (range, 31–38 kg/m2; mean, 34 kg/m2), the tube current had to be increased to retain sufficient image quality. Only patients with a BMI of 30 and higher showed a significant correlation between BMI and dose-length product ( P value = 0.02), resulting in a slightly increased dose ( P value = 0.002). Conclusion The protocol presented for the interventional part of CT-guided periradicular infiltration allows to safely treat patients with a median calculated effective dose of 0.045 mSv (converted from a dose-length-product of 2.26 mGy*cm). Patients with a BMI of 30 and higher required a higher calculated effective dose with just one patient slightly exceeding 0.1 mSv.