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Significant Reduction of Radiation Exposure Using Specific Settings of the O-Arm for Percutaneous Cementoplasty in Accordance With the ALARA Principle

BACKGROUND

Three-dimensional (3D) navigation has become routinely used in spine surgery, allowing more accurate and safe procedures. However, radiation exposure related to the use of imaging is an unresolved issue, and information about it is relatively scarce. The "as low as reasonably achievable" (ALARA) principle aims to reduce the radiation exposure for the patients as low as possible. The objective of this study was to compare the effective dose related to the use of the O-arm in standard settings with adapted features for dose reduction during percutaneous cementoplasty.

METHODS

From March 2021 to October 2022, all consecutive patients who underwent navigated percutaneous cementoplasty with the use of the O-arm were prospectively included. Demographic, operative, irradiation, and radiological data were collected. The main outcome was the effective dose (E) in millisievert (mSv). Secondary outcomes were the absolute risk of cancer (AR) in percent equivalent to a whole-body exposition, operative time, and radiological results according to Garnier. In group A, patients were operated on with standard settings of the O-arm, whereas in group B, navigation on the field of view, collimation, and low-dose settings were used.

RESULTS

A total of 70 patients were included in the study: 43 in group A and 27 in group B. Also, 109 vertebrae were operated: 59 in group A and 50 in group B. Mean E was significantly higher in group A than in group B (9.94 and 4.34 mSv, respectively; P < 0.01). The 3D-related E followed the same trend (7.82 and 3.97 mSv, respectively), as did 2-dimensional-related E (2.12 and 0.37 mSv, respectively; P < 0.01). Average AR was also significantly higher in group A than in group B (5.10-4% and 2.10-4% respectively; P < 0.01). Operative time was similar in both groups, but the rate of satisfactory radiological results was higher in group A than in group B (95% and 84%, respectively; P = 0.11), and we found similar rates of cement leakage (22% and 24%, respectively; P = 0.71).

CONCLUSIONS

The application of settings of the O-arm in accordance with the ALARA principle helped to significantly reduce the radiation exposure and should be routinely used for O-arm-assisted cementoplasty procedures.

CLINICAL RELEVANCE

This study details technical aspects and settings that may help users of the O-arm to decrease radiation exposure to patients and surgeons alike, especially in cementoplasty procedures, as well as in other procedures performed under O-arm guidance.

LEVEL OF EVIDENCE: 2

The Role of a Navigational Radiofrequency Ablation Device and Concurrent Vertebral Augmentation for Treatment of Difficult-to-Reach Spinal Metastases

Aims: The purpose of this study was to assess the effectiveness of a navigational radiofrequency ablation device with concurrent vertebral augmentation in the treatment of posterior vertebral body metastatic lesions, which are technically difficult to access. Primary outcomes of the study were evaluation of pain palliation and radiologic assessment of local tumor control. Materials and Methods: Thirty-five patients with 41 vertebral spinal metastases involving the posterior vertebral body underwent computed tomography-guided percutaneous targeted radiofrequency ablation, with a navigational radiofrequency ablation device, associated with vertebral augmentation. Twenty-one patients (60%) had 1 or 2 metastatic lesions (Group A) and fourteen (40%) patients had multiple (>2) vertebral lesions (Group B). Changes in pain severity were evaluated by visual analog scale (VAS). Metastatic lesions were evaluated in terms of radiological local control. Results: The procedure was technically successful in all the treated vertebrae. Among the symptomatic patients, the mean VAS score dropped from 5.7 (95% CI 4.9–6.5) before tRFA and to 0.9 (95% CI 0.4–1.3) after tRFA (p < 0.001). The mean decrease in VAS score between baseline and one week follow up was 4.8 (95% CI 4.2–5.4). VAS decrease over time between one week and one year following radiofrequency ablation was similar, suggesting that pain relief was immediate and durable. Neither patients with 1–2 vertebral metastases, nor those with multiple lesions, showed radiological signs of local progression or recurrence of the tumor in the index vertebrae during a median follow up of 19 months (4–46 months) and 10 months (4–37 months), respectively. Conclusion: Treatment of spinal metastases with a navigational radiofrequency ablation device and vertebral augmentation can be used to obtain local tumor control with immediate and durable pain relief, providing effective treatment in the multimodality management of difficult-to-reach spinal metastases.

[Low cement distribution index is a risk factor for refracture of the adjacent segments after percutaneous vertebroplasty]

OBJECTIVE

To investigate the impact of cement distribution index on the occurrence of refracture in the adjacent segments after percutaneous vertebroplasty.

METHODS

This retrospective analysis was conducted among 143 patients who received percutaneous vertebroplasty for osteoporotic vertebral compression fracture between April, 2011 and April, 2014. Of the 134 patients with complete follow-up data, 18 had adjacent segment fracture within 1 year following the surgeries (re-fracture group), and 116 patients without new fracture served as the control group. All the patients underwent X-ray examinations after the surgery and according to the position and shape, the cement in the vertebrae were classified into 5 types (I to V), and the volume-cubage index was computed based on the cement volume and vertebral cubage. Age, gender, bone mineral density (BMD), cement distribution index, volume-cubage index, and cement leakage were evaluated in the 2 groups, and the variables with significant differences between the 2 groups were analyzed in Logistic regression analysis.

RESULTS

BMD was significantly lower and the rate of cement leakage was significantly higher in the re-fracture group than in the control group (P<0.05). Significant difference was found in cement distribution index between the 2 groups (P<0.05) but not in age, gender, cement volume or volume-cubage index (P>0.05). Logistic regression analysis indicated that BMD, cement leakage and cement distribution index all significantly affected the occurrence of adjacent vertebral fractures following percutaneous vertebroplasty.

CONCLUSION

A low BMD, cement leakage and a low cement distribution index are all risks factor of adjacent vertebral fracture after percutaneous vertebroplasty.