PATIENT POSITIONING USING IMPLANTED GOLD MARKERS WITH THE NOVALIS BODY SYSTEM IN THE THORACIC SPINE

Publication patterns of comparative effectiveness research in spine neurosurgery

OBJECT

The purpose of this study was to investigate publication patterns for comparative effectiveness research (CER) on spine neurosurgery.

METHODS

The authors searched the PubMed database for the period 1980-2012 using the key words "cost analysis," "utility analysis," "cost-utility," "outcomes research," "practical clinical research," "comparator trial," and "comparative effectiveness research," linked with "effectiveness" and "spine neurosurgery."

RESULTS

From 1980 through April 9, 2012, neurosurgery CER publications accounted for 1.38% of worldwide CER publications (8657 of 626,330 articles). Spine neurosurgery CER accounted for only 0.02%, with 132 articles. The journal with the greatest number of publications on spine neurosurgery CER was Spine, followed by the Journal of Neurosurgery: Spine. The average annual publication rate for spine neurosurgery CER during this period was 4 articles (132 articles in 33 years), with 68 (51.52%) of the 132 articles being published within the past 5 years and a rising trend beginning in 2008. The top 3 contributing countries were the US, Turkey, and Japan, with 68, 8, and 7 articles, respectively. Only 8 regular articles (6.06%) focused on cost analysis.

CONCLUSIONS

There is a paucity of publications using CER methodology in spine neurosurgery. Few articles address the issue of cost analysis. The promotion of continuing medical education in CER methodology is warranted. Further investigations to address cost analysis in comparative effectiveness studies of spine neurosurgery are crucial to expand the application of CER in public health.

Successful treatment of a T4 lung tumor with vertebral body invasion using fiducial markers in the thoracic spine for image-guided radiation therapy: A case report

Introduction

Paravertebral and paraspinal tumors pose a significant challenge in radiation therapy because of the radiation sensitivity of the spinal cord and the need for maximum treatment accuracy. Implantation of fiducial markers into vertebral bodies has been described as a method of increasing the accuracy of radiation treatment for single-dose stereotactic radiosurgery for spinal and paraspinal primary tumors and metastases. However, utilization of this technique has not been described for conventionally fractionated radiation therapy. This report is the first of its kind in the literature and describes successful treatment of a T4 primary lung tumor with vertebral body invasion with conventionally fractionated, image-guided radiotherapy using fiducial markers implanted in the thoracic spine.

Case presentation

Our patient was a 47-year-old African-American man who presented to our hospital with a history of several months of increasing left arm pain, chest pain, dyspnea on exertion, occasional dry cough, and weight loss. He was found to have stage IIIA T4, N0, M0 lung cancer with vertebral body invasion. He had fiducial markers placed in the thoracic spine for image-guided radiation treatment set-up. The patient received 74 Gy radiation therapy with concurrent chemotherapy, and daily matching of the fiducial markers on the treatment machine allowed for treatment of the tumor while sparing the dose to the adjacent spinal cord. With one year of clinical follow-up, the patient has had regression of the tumor with only asymmetric soft-tissue thickening seen on a computed tomographic scan and grade 1 dyspnea on exertion as the only side effects of the treatment.

Conclusion

Fiducial marker placement is a safe and effective technique for maximizing the accuracy and reproducibility for radiation treatment of lesions near the spinal cord. This technique may be used in conventionally fractionated radiation treatment regimens, such as those employed to treat a lung tumor with vertebral body invasion, to potentially improve clinical outcomes for patients.

Setup accuracy of spine radiosurgery using cone beam computed tomography image guidance in patients with spinal implants

OBJECT

Cone beam computed tomography (CBCT) image guidance technology has been adopted for use in spine radiosurgery. There is concern regarding the ability to safely and accurately perform spine radiosurgery without the use of implanted fiducials for image guidance in postsurgical cases in which titanium instrumentation and/or methylmethacrylate (MMA) has been implanted. In this study the authors prospectively evaluated the accuracy of the patient setup for spine radiosurgery by using CBCT image guidance in the context of orthopedic hardware at the site of disease.

METHODS

The positioning deviations of 31 single-fraction spine radiosurgery treatments in patients with spinal implants were prospectively evaluated using the Elekta Synergy S 6-MV linear accelerator with a beam modulator and CBCT image guidance combined with a robotic couch that allows positioning correction in 3 translational and 3 rotational directions. To measure patient movement, 3 quality-assurance CBCT studies were performed and recorded: before, halfway through, and after radiosurgical treatment. The positioning data and fused images of planning CTs and CBCTs from the treatments were analyzed to determine intrafractional patient movements. From each of 3 CBCTs, 3 translational and 3 rotational coordinates were obtained.

RESULTS

The prescribed dose to the gross tumor volume for the cohort was 12-18 Gy (mean 14 Gy) utilizing 9-14 coplanar intensity-modulated radiation therapy (IMRT) beams (mean 10 beams). At the halfway point of the radiosurgery, the translational variations and standard deviations were 0.6 +/- 0.6, 0.4 +/- 0.4, and 0.5 +/- 0.5 mm in the lateral (X), longitudinal (Y), and anteroposterior (Z) directions, respectively. The magnitude of the 3D vector (X,Y,Z) was 1.1 +/- 0.7 mm. Similarly, the variations immediately after treatment were 0.5 +/- 0.3, 0.4 +/- 0.4, and 0.5 +/- 0.6 mm along the X, Y, and Z directions, respectively. The 3D vector was 1.0 +/- 0.6 mm. The mean rotational angles were 0.3 +/- 0.4, 0.5 +/- 0.6, and 0.3 +/- 0.4 degrees along yaw, roll, and pitch, respectively, at the halfway point and 0.3 +/- 0.4, 0.6 +/- 0.6, and 0.4 +/- 0.5 degrees immediately after treatment.

CONCLUSIONS

Cone beam CT image guidance used for patient setup for spine radiosurgery was highly accurate despite the presence of spinal instrumentation and/or MMA at the level of the target volume. The presence of such spinal implants does not preclude safe treatment via spine radiosurgery in these patients.