1. Radiation Dose and Fluoroscopic Time of Fluoroscopic-guided Lumbar Puncture Zoghbi B, Sharma K, Hadi S, Al-Sabbagh M, Aquino B, Spampinato MV Department of Radiology and Radiological Science Medical University of South Carolina, Charleston, SC American Society of Neuroradiology Meeting Chicago, April 2015 EP # 143

2. Myself, other authors, and my immediate family members do not have a financial relationship with a commercial organization that may have a direct or indirect interest in the content. Disclosure of Commercial Interest

3. Background and Purpose Fluoroscopic-guided lumbar puncture is an effective alternative to bedside lumbar puncture in challenging patients. No published guidelines are available for an acceptable range of fluoroscopic time for this procedure. The purpose of this study is to retrospectively evaluate radiation dose and fluoroscopic time in fluoroscopic- guided lumbar puncture (FGLP).

4. Methods: Patient Population We retrospectively reviewed all FGLP performed at our institution during nine consecutive months (October 2, 2013 to June 30, 2014). The radiology information system at our hospital was searched by using the procedure code for FGLP to identify subjects. We excluded all myelograms and cases where fluoroscopic time and radiation doses were not recorded in the EMR.

5. All FGLP procedures were performed in the prone or left lateral decubitus position using a sterile technique. FGLPs were performed at L2-L3, L3-L4, L4-L5 or L5-S1 levels. 22-gauge spinal needles were most commonly used. Three neuroradiology fellows and a physician assistant performed the FGLP during the study period. Faculty directly or indirectly supervised trainees. Methods: Procedure Technique

6. Methods: Data Collection The procedure reports and stored images were reviewed by using the Picture Archiving and Communication System (PACS). Fluoroscopic time, radiation dose, operator, clinical indication, puncture site, patient age and gender were collected from the radiology report.

7. We performed group comparisons of patients stratified by: Age Gender Puncture site Operator Study indication Statistical analyses were conducted using Mann-Whitney tests. Differences were considered statistically significant when p < 0.05. Methods: Data Analysis

8. 188 FGLPs were included in the study (median age [SD] = 47 [19], age range = 10 - 86; 68 males, 120 females). 18 FGLPs were excluded because fluoroscopic time and radiation dose were not available on PACS. Results

9. Clinical indications for the FGLPs were as follows: Altered mental status (17 cases) Abnormal neurologic exam (13 cases) Leptomeningeal tumor (33 cases) Infection (30 cases) Idiopathic intracranial hypertension (61 cases) Demyelinating / inflammatory disease (22 cases) Normal pressure hydrocephalus (6 cases) Seizure disorder (2 cases) Miscellaneous other indications (4 cases) Results

10. Median fluoroscopy time (range, SD) = 26 seconds (6 -193, 29) Results Median radiation dose (range, SD) = 9.6 mGy (0.9 -263, 31) Fluoroscopic Time (seconds) Radiation Dose (mGy)

11. Fluoroscopy time but not radiation dose were significantly different among operators (respectively p = 0.02 and p = 0.062). There was no significant difference in fluoroscopy time and radiation exposure between the three fellows and the physician assistant. Results Fluoroscopic Time (seconds) Radiation Dose (mGy)

12. Fluoroscopy time but not radiation dose estimates were significantly lower in patients younger than 50 years (respectively p = 0.004 and p = 0.467). Results Radiation Exposure (mGy) Fluoroscopic Time (seconds) Radiation Dose (mGy)

13. Top 3 indications for FGLP were tumor (N = 33), infection (N = 30), idiopathic intracranial hypotension (N = 61). Radiation dose but not fluoroscopic time were significantly different across indication categories (p = 0.001 and p = 0.425), with the greatest radiation dose in patients referred for idiopathic intracranial hypertension (IIH). Results Radiation Exposure (mGy) Fluoroscopic Time (seconds) Radiation Dose (mGy)

14. There were no significant differences in fluoroscopic time or radiation dose between puncture sites. There were no significant differences in fluoroscopic time or radiation dose between males and females. Results Fluoroscopic Time (seconds) Radiation Dose (mGy)

15. Fluoroscopic Time and Radiation Dose Estimates by Clinical Indication IndicationCountRD*FT** Altered mental status1714.9 (9.5)33 (9.5) Abnormal neuro exam1317.5 (12)41.6 (13) Infection3011.8 (20)30.7 (24) IIH6137 (44.6)44 (38) Demyelinating / Inflammatory2213.4 (25)34 (36.5) NPH610.9 (8)38.5 (29) Seizure disorder223 (19)41.6 (31) Leptomeningeal tumor337 (5)24 (11) Miscellaneous421.5 (33)37.6 (36) * Mean Radiation Dose in mGy (SD) ** Mean Fluoroscopy Time in seconds (SD)

16. Patients with IIH present a greater challenge to successful bedside LP due to elevated BMI and difficulty in palpating the bony landmarks. Laxity of adipose tissues and need for longer needles to reach the thecal sac lengthen the procedure and potentially increase the amount of radiation dose. FGLP performed in patients with IIH had the highest mean fluoroscopy time (44 seconds) and mean radiation dose estimates (37 mGy). Discussion

17. Limitations Retrospective study performed at a single institution Regionally specific patient population No control for patient anxiety, ability and willingness to cooperate, individual pain threshold, pre-existing degenerative changes or spinal stenosis, and postsurgical scar tissue or hardware, that could certainly impact the procedure time BMI (body mass index) data were not available

18. We evaluated the radiation dose and fluoroscopic time in fluoroscopic-guided lumbar punctures at our institution as part of a quality improvement project. Monitoring fluoroscopic time and radiation dose in fluoroscopic-guided lumbar puncture is essential to ensure the quality and safety of this procedure and to minimize radiation exposure for both patients and radiation health workers. Conclusion

19. References 1. Boddu SR, Corey A, Peterson R et al. Fluoroscopic-Guided Lumbar Puncture: Fluoroscopic Time and Implications of Body Mass Index-A Baseline Study. AJNR Am J neuroradiol 35:1475-80 Aug 2014 2. Brook AD, Burns J, Dauer E, et al. Comparison of CT and fluoroscopic guidance for lumbar puncture in an obese population with prior failed unguided attempt. J Neurointerv Surg May 2014;6:324-28 3. Smuck M, Zheng P, Chong T, et al. Duration of fluoroscopic-guided spine interventions and radiation exposure is increased in over-weight patients. PM R 2013;5: 291-96, quiz 296 4. Eskey CJ, Ogilvy CS. Fluoroscopy-guided lumbar puncture: decreased frequency of traumatic tap and implications for the assessment of CT-negative acute subarachnoid hemorrhage. AJNR Am J Neuroradiol 2001; 22:571-76 5. Edwards C, Leira EC, Gonzalez-Alegre P. Residency Training : A failed lumbar puncture is more about obesity than lack of ability. Neurology, 2015 Mar 10;84(10): e 69-72

20. Questions? zoghbi@musc.edu Thank you!