Radiology Education Memorial Award Winning Paper
Simulation-Based Educational Curriculum for Fluoroscopically Guided Lumbar Puncture Improves Operator Confidence and Reduces Patient Dose Austin R. Faulkner, MD, Austin C. Bourgeois, MD, Yong C. Bradley, MD, Kathleen B. Hudson, MD, R. Eric Heidel, PhD, Alexander S. Pasciak, PhD Rationale and Objectives: Fluoroscopically guided lumbar puncture (FGLP) is a commonly performed procedure with increased success rates relative to bedside technique. However, FGLP also exposes both patient and staff to ionizing radiation. The purpose of this study was to determine if the use of a simulation-based FGLP training program using an original, inexpensive lumbar spine phantom could improve operator confidence and efficiency, while also reducing patient dose. Materials and Methods: A didactic and simulation-based FGLP curriculum was designed, including a 1-hour lecture and hands-on training with a lumbar spine phantom prototype developed at our institution. Six incoming post-graduate year 2 (PGY-2) radiology residents completed a short survey before taking the course, and each resident practiced 20 simulated FGLPs using the phantom before their first clinical procedure. Data from the 114 lumbar punctures (LPs) performed by the six trained residents (prospective cohort) were compared to data from 514 LPs performed by 17 residents who did not receive simulation-based training (retrospective cohort). Fluoroscopy time (FT), FGLP success rate, and indication were compared. Results: There was a statistically significant reduction in average FT for the 114 procedures performed by the prospective study cohort compared to the 514 procedures performed by the retrospective cohort. This held true for all procedures in aggregate, LPs for myelography, and all procedures performed for a diagnostic indication. Aggregate FT for the prospective group (0.87 0.68 minutes) was significantly lower compared to the retrospective group (1.09 0.65 minutes) and resulted in a 25% reduction in average FT (P = .002). There was no statistically significant difference in the number of failed FGLPs between the two groups. Conclusions: Our simulation-based FGLP curriculum resulted in improved operator confidence and reduced FT. These changes suggest that resident procedure efficiency was improved, whereas patient dose was reduced. The FGLP training program was implemented by radiology residents and required a minimal investment of time and resources. The LP spine phantom used during training was inexpensive, durable, and effective. In addition, the phantom is compatible with multiple modalities including fluoroscopy, computed tomography, and ultrasound and could be easily adapted to other applications such as facet injections or joint arthrograms. Key Words: Lumbar puncture; fluoroscopy; dose reduction; simulation training. ªAUR, 2015
Acad Radiol 2015; 22:668–673 From the Department of Radiology, University of Tennessee Graduate School of Medicine, 1924 Alcoa Hwy, UTMC Nuclear Medicine, Knoxville, TN 37920 (A.R.F., A.C.B., Y.C.B., K.B.H., A.S.P.); Department of Biostatistics, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee (R.E.H.); and Department of Radiology, University of Tennessee Medical Center, Knoxville, Tennessee (A.S.P.). Received November 5, 2014; accepted December 12, 2014. Conflicts of Interest: No authors declare any conflict of interest. Address correspondence to: A.S.P. e-mail: [email protected] ªAUR, 2015 http://dx.doi.org/10.1016/j.acra.2014.12.024
668
L
umbar puncture (LP) is a commonly performed procedure used to provide access into the intrathecal subarachnoid space, either for diagnostic and/or therapeutic collection of cerebrospinal fluid or for the intrathecal administration of medications such as contrast media or chemotherapeutic agents. Although classically performed at the bedside using visual and palpable landmarks, the use of image guidance is associated with increased success rates and has been shown to decrease the rate of traumatic LP (1). The use of image guidance is particularly useful for difficult cases such as patients with
Academic Radiology, Vol 22, No 5, May 2015
SIMULATION-BASED EDUCATIONAL CURRICULUM FOR FGLP
severe scoliosis, lumbar hardware, or morbid obesity (2). Fluoroscopically guided LP (FGLP) is considered a core competency and is listed in the diagnostic radiology residency milestones by the American College of Graduate Medical Education and the American Board of Radiology (3,4). Fluoroscopy is an essential component of many imageguided procedures because it provides real-time visualization of procedural instruments and patient anatomy. However, the use of fluoroscopy is not entirely benign. Fluoroscopy exposes both the patient and staff members to potentially high levels of ionizing radiation (5). In 2006, the National Council on Radiation Protection released a report describing a 5.7fold increase in annual effective radiation dose per individual in the US population owing to medical imaging from 1980 to 2006 (6). More recently, a Sentinel Event Alert from the Joint Commission in 2011 regarding the radiation risks of diagnostic imaging noted that the average radiation exposure in the United States is 4.7 times that of the global population (3 mSv per individual in the United States compared to 0.64 mSv per individual globally) (7). Because physicians directly control the fluoroscope during image-guided procedures, radiation dose is significantly affected by physician technique (8). It is extremely important that operators of fluoroscopic equipment be appropriately trained in the safe use of such machines and that all exposure to ionizing radiation is kept as low as reasonably achievable (9). Prior studies have shown that formal training programs regarding the safe and appropriate use of fluoroscopy during image-guided procedures can result in significantly reduced radiation doses (10). The purpose of this article is to present the results of a formal training program designed to prepare radiology residents at our institution to safely and efficiently perform FGLP. Finding or creating an appropriate model is an essential step in the development of any hands-on simulation-based training program. As part of the simulation-based LP training curriculum developed at our institution, we designed and created a custom lumbar spine phantom that is similar anatomically and fluoroscopically to human anatomy. This prototype FGLP phantom is inexpensive, robust, and durable and is designed to provide the visual and tactile simulation of FGLP necessary for resident training (11). This work evaluates whether the use of this phantom in combination with a short didactic training session can improve operator confidence and reduce procedure time and radiation dose while maintaining patient safety for FGLPs performed by resident trainees. MATERIALS AND METHODS Data and survey collection for this project was performed with institutional review board approval. Written consent was obtained from all resident trainees who participated in this study. The formal FGLP training program consisted of a 1 hour didactic curriculum with prelecture and postlecture surveys designed to assess knowledge of technique and anatomy, followed by multiple simulated LPs using the fluoroscopically accurate lumbar spine phantom. Before starting the didactic
portion of the training, each resident completed a baseline survey to assess his or her understanding of lumbar spine anatomy and fluoroscopic technique. The didactic lecture provided a review of the relevant anatomy, discussed indications and contraindications for performing FGLP, and outlined the risks and potential complications of the procedure. Pertinent anatomic and radiographic landmarks of the lumbar spine were reviewed, including the vertebral body, facet, pedicle, lamina, spinous process, intervertebral foramen, supraspinous ligament, interspinous ligament, ligamentum flavum, and dura. Common indications and risks for both diagnostic and therapeutic LP were discussed and the procedural differences outlined in detail. The didactic lecture (available in the Appendix) was given to each resident individually immediately before the start of their first neuroradiology rotation. After completion of the didactic training, the residents each performed 20 FGLP simulations over a 1-week time frame using our original lumbar spine phantom. The lumbar spine phantom was created from materials selected on their tactile and fluoroscopic similarity to bone and soft tissue. A lumbar spine model made of injectionmolded polyvinyl chloride (PVC) was used for the core of the phantom, and the soft tissue substitute was made with a thermoplastic polymer (Kraton D1111 K polystyrene-polyisoprene–polystyrene triblock thermoplastic polymer; Kraton Performance Polymers, Inc.). This synthetic tissue substitute was selected because it was inexpensive, colorless, radiolucent, and provided a tactile feel similar to that of human tissue. After mixing the thermoplastic polymer with mineral oil and heating until liquefied, the PVC lumbar spine model was suspended in the gelatin solution, and the phantom was allowed to cool. The creation process for the lumbar spine phantom required 10 hours to complete (including heating time to liquefy the polymer and cooling time to allow the polymer to set). This phantom has a total material cost of approximately US$148.00 and is anatomically accurate when viewed under fluoroscopy as shown in Figure 1. Further details related to the construction of this phantom can be found elsewhere (11). After 20 simulated LPs, residents were asked to subjectively rate confidence in their ability to perform an FGLP, both before and after completion of the training program (on a scale of 1–10; 1: very little confidence, 10: very confident). FGLP was performed with either personal or direct supervision from an attending physician, and informed consent was obtained from each patient before the start of the procedure. FGLPs were performed using sterile technique with the patient in either the prone or the prone oblique position, and intrathecal access was obtained primarily at the L3–L4 or L2–L3 levels. All prospective and retrospective procedures considered in this study were performed on one of two identical Philips Super 80 CO fluoroscopic units (Philips Healthcare, Andover, MA). Recorded data (for both retrospective and prospective procedures) included the type of procedure performed (diagnostic LP, myelogram, and so forth), indication for the procedure, primary operator (and additional operators in the case of unsuccessful attempts), and total fluoroscopy time (FT, minutes). 669
FAULKNER ET AL
Academic Radiology, Vol 22, No 5, May 2015
Figure 1. (a) Anterior–posterior view under live fluoroscopy of the fluoroscopically guided lumbar puncture (FGLP) training phantom used in this study. (b) Anterior– posterior view under live fluoroscopy of a human subject undergoing an FGLP.
Prospective procedural data from 114 LPs performed by the six post-graduate year 2 (PGY-2) residents (the prospective group) after completion of the simulation-based training program were compared to retrospective data from 514 LPs performed by 17 residents over the past 3 years who did not receive simulation-based training (the retrospective group). Both data subsets represent LPs performed by each resident during their first 1-month neuroradiology rotation. The retrospective data were composed of the first 15–25 LPs and/or myelograms performed by residents dating back to the 2010–2011 residency class representing each classes’ first rotation where multiple FGLPs were performed. The collected data points include the total FT, procedure type (ie, diagnostic LP vs. myelogram), unsuccessful LP attempts, and the clinical indication for each procedure. Clinical indications were grouped into the following nine subcategories: suspected meningitis, pseudotumor cerebri, subarachnoid hemorrhage, demyelinating disease, myelogram/cisternogram, intrathecal chemotherapy administration, normal pressure hydrocephalus, malignancy workup, and other. FTs and procedure success rate for each group (prospective and retrospective) were compared in aggregate, as well as by procedure type (diagnostic LP vs. intrathecal contrast administration for myelography). Each group was also compared based on failure rate, both in aggregate and by indication. Radiation dose and 670
the speed and efficiency at which residents performed the FGLP were evaluated using FT, whereas failure rate served as a measure of patient safety. Operator confidence was subjectively evaluated using the aforementioned survey after training with the spine phantom. Frequency statistics were performed on all categorical variables. Skewness and kurtosis statistics were used to assess normality for all continuous variables. Levene test was used to check for the assumption of homogeneity of variance. Independent samples t tests were used to compare resident groups on continuous outcomes. Mann–Whitney U tests were used when any statistical assumption was violated. Chi-square analyses were used to detect significant associations between resident groups and categorical outcomes. All analyses were conducted using SPSS, version 21 (IBM Corp., Armonk, NY), and statistical significance was assumed at a Bonferroni-corrected alpha value of .01. RESULTS Before the formal training program and before performing any FGLP procedures, the six PGY-2 residents who served as the prospective study cohort were asked to rate how confident they were in their ability to perform an FGLP. The average operator confidence was 3 of 10 on the initial survey
Academic Radiology, Vol 22, No 5, May 2015
SIMULATION-BASED EDUCATIONAL CURRICULUM FOR FGLP
Figure 3. Average fluoroscopy time for procedures performed for each indication. Error bars represent standard deviations.
Figure 2. Average fluoroscopy time for all procedures in aggregate, for all procedures with a diagnostic indication, and for all myelograms. Error bars represent standard deviations.
(1: very little confidence, 10: very confident). Average operator confidence increased greatly after training, climbing to 8.7 of 10 after completion of the didactic lecture and 20 simulated FGLPs with the lumbar spine phantom. Results from the pretraining and posttraining survey designed to gauge the residents’ knowledge of LP anatomy and procedural techniques also showed a large improvement, increasing from 38 of 54 questions answered correctly (70.4%) before training to 54 of 54 correct answers (100%) after completion of the training program. Clinical indications for FGLP procedures were subdivided into nine categories. The rate of unsuccessful FGLP and average FT for each group (prospective and retrospective) were compared in aggregate and by indication (Figs 2 and 3). The prospective cohort only performed a single examination for indication 8 (malignancy workup), and no procedures based on indication 9 (other), so comparisons could not be made for those indications. Average FT and standard deviation for the first seven indications are shown in Figure 3 and Table 1. There was a single unsuccessful FGLP in the 114 procedures performed by the prospective group (0 of 73 diagnostic LPs and 1 of 41 myelograms), and a total of seven unsuccessful FGLPs in the 514 procedures performed by the retrospective cohort (2 of 333 diagnostic LPs and 5 of 174 myelograms). The rate of unsuccessful FGLP was not statistically significant between the two groups, in aggregate or by indication (P = .56). There was a statistically significant reduction in average FT for the 114 procedures performed by the prospective group compared to the 514 procedures performed by the retrospective resident cohort (Table 2). This held true for all procedures
TABLE 1. Average Fluoroscopy Time (Minutes) for All Indications in Prospective versus Retrospective Study Cohorts
Indication Meningitis Pseudotumor SAH Demyelination Myelography Intrathecal chemotherapy NPH
Avg. Fluoro Time (Prospective), Minutes
Avg. Fluoro Time (Retrospective), Minutes
P Value
1.09 0.51 1.04 0.57 0.98 0.52
0.97 1.02 0.93 0.86 1.39 0.82
.87 .009* .8 .09 .001* .04*
1.03
0.91
.43
Avg., average; NPH, normal pressure hydrocephalus; SAH, subarachnoid hemorrhage. *Indicates a statistically significant difference between prospective and retrospective groups.
in aggregate, LPs for myelography, and all combined diagnostic procedures (all indications other than indication 5: myelogram/cisternogram). When subdivided by indication, there were statistically significant differences in average FT for indications 2 (pseudotumor), 5 (myelogram/cisternogram), and 6 (intrathecal chemotherapy administration). In aggregate, the prospective group showed a 25% reduction in average FT compared to the retrospective group (0.87 0.68 minutes prospective vs. 1.09 0.65 minutes retrospective; P = .002). This reduction in average FT remained when procedures were subdivided based on procedure type. There were 73 successful LPs performed for a diagnostic indication in the prospective group and 329 successful diagnostic LPs performed by the retrospective group (0.81 0.707 minutes prospective vs. 0.935 0.555 minutes retrospective; P = .002). Similarly, there were 40 successful myelograms performed by the 671
FAULKNER ET AL
Academic Radiology, Vol 22, No 5, May 2015
TABLE 2. Average Fluoroscopy Time (Minutes) for Prospective versus Retrospective Study Cohorts Avg. Fluoro Time Avg. Fluoro Time (Retrospective), P (Prospective), Minutes Value Minutes Diagnostic LP LP for myelogram All FGLP (total)
0.81 0.98 0.87
0.94 1.4 1.09
.002* .001* .002*
Avg., average; FGLP, fluoroscopically guided lumbar puncture; LP, lumbar puncture. *Indicates a statistically significant difference between prospective and retrospective groups.
prospective group and 164 successful myelograms performed by the retrospective group (0.978 0.619 minutes prospective vs. 1.387 0.728 minutes retrospective; P = .001). There were no statistically significant differences in success/failure rate between the two groups when procedures were subdivided based on indication.
DISCUSSION Radiology training programs have taught the importance of radiation safety and dose reduction for years, but this has become an even larger focus as the radiation exposure associated with medical imaging has continued to rise and public awareness has increased. FGLP is one of the more common image-guided procedures performed by radiologists. Prior studies have shown that the level of operator experience has a significant effect on the average FT associated with these procedures (2). One way to increase that level of experience without adversely impacting patient safety is through the use of hands-on simulation-based training programs (12). Our results support these previous findings (12) in the context of FGLP as, for many indications and in aggregate, FT was reduced without any statistically significant change in procedure success. We have designed an FGLP training curriculum that combines a didactic review of anatomy and procedural technique with hands-on simulation using a novel, fluoroscopically visible lumbar spine phantom. The LP phantom prototype created at our institution cost
Simulation-Based Educational Curriculum for Fluoroscopically Guided Lumbar Puncture Improves Operator Confidence and Reduces Patient Dose Austin R. Faulkner, MD, Austin C. Bourgeois, MD, Yong C. Bradley, MD, Kathleen B. Hudson, MD, R. Eric Heidel, PhD, Alexander S. Pasciak, PhD Rationale and Objectives: Fluoroscopically guided lumbar puncture (FGLP) is a commonly performed procedure with increased success rates relative to bedside technique. However, FGLP also exposes both patient and staff to ionizing radiation. The purpose of this study was to determine if the use of a simulation-based FGLP training program using an original, inexpensive lumbar spine phantom could improve operator confidence and efficiency, while also reducing patient dose. Materials and Methods: A didactic and simulation-based FGLP curriculum was designed, including a 1-hour lecture and hands-on training with a lumbar spine phantom prototype developed at our institution. Six incoming post-graduate year 2 (PGY-2) radiology residents completed a short survey before taking the course, and each resident practiced 20 simulated FGLPs using the phantom before their first clinical procedure. Data from the 114 lumbar punctures (LPs) performed by the six trained residents (prospective cohort) were compared to data from 514 LPs performed by 17 residents who did not receive simulation-based training (retrospective cohort). Fluoroscopy time (FT), FGLP success rate, and indication were compared. Results: There was a statistically significant reduction in average FT for the 114 procedures performed by the prospective study cohort compared to the 514 procedures performed by the retrospective cohort. This held true for all procedures in aggregate, LPs for myelography, and all procedures performed for a diagnostic indication. Aggregate FT for the prospective group (0.87 0.68 minutes) was significantly lower compared to the retrospective group (1.09 0.65 minutes) and resulted in a 25% reduction in average FT (P = .002). There was no statistically significant difference in the number of failed FGLPs between the two groups. Conclusions: Our simulation-based FGLP curriculum resulted in improved operator confidence and reduced FT. These changes suggest that resident procedure efficiency was improved, whereas patient dose was reduced. The FGLP training program was implemented by radiology residents and required a minimal investment of time and resources. The LP spine phantom used during training was inexpensive, durable, and effective. In addition, the phantom is compatible with multiple modalities including fluoroscopy, computed tomography, and ultrasound and could be easily adapted to other applications such as facet injections or joint arthrograms. Key Words: Lumbar puncture; fluoroscopy; dose reduction; simulation training. ªAUR, 2015
Acad Radiol 2015; 22:668–673 From the Department of Radiology, University of Tennessee Graduate School of Medicine, 1924 Alcoa Hwy, UTMC Nuclear Medicine, Knoxville, TN 37920 (A.R.F., A.C.B., Y.C.B., K.B.H., A.S.P.); Department of Biostatistics, University of Tennessee Graduate School of Medicine, Knoxville, Tennessee (R.E.H.); and Department of Radiology, University of Tennessee Medical Center, Knoxville, Tennessee (A.S.P.). Received November 5, 2014; accepted December 12, 2014. Conflicts of Interest: No authors declare any conflict of interest. Address correspondence to: A.S.P. e-mail: [email protected] ªAUR, 2015 http://dx.doi.org/10.1016/j.acra.2014.12.024
668
L
umbar puncture (LP) is a commonly performed procedure used to provide access into the intrathecal subarachnoid space, either for diagnostic and/or therapeutic collection of cerebrospinal fluid or for the intrathecal administration of medications such as contrast media or chemotherapeutic agents. Although classically performed at the bedside using visual and palpable landmarks, the use of image guidance is associated with increased success rates and has been shown to decrease the rate of traumatic LP (1). The use of image guidance is particularly useful for difficult cases such as patients with
Academic Radiology, Vol 22, No 5, May 2015
SIMULATION-BASED EDUCATIONAL CURRICULUM FOR FGLP
severe scoliosis, lumbar hardware, or morbid obesity (2). Fluoroscopically guided LP (FGLP) is considered a core competency and is listed in the diagnostic radiology residency milestones by the American College of Graduate Medical Education and the American Board of Radiology (3,4). Fluoroscopy is an essential component of many imageguided procedures because it provides real-time visualization of procedural instruments and patient anatomy. However, the use of fluoroscopy is not entirely benign. Fluoroscopy exposes both the patient and staff members to potentially high levels of ionizing radiation (5). In 2006, the National Council on Radiation Protection released a report describing a 5.7fold increase in annual effective radiation dose per individual in the US population owing to medical imaging from 1980 to 2006 (6). More recently, a Sentinel Event Alert from the Joint Commission in 2011 regarding the radiation risks of diagnostic imaging noted that the average radiation exposure in the United States is 4.7 times that of the global population (3 mSv per individual in the United States compared to 0.64 mSv per individual globally) (7). Because physicians directly control the fluoroscope during image-guided procedures, radiation dose is significantly affected by physician technique (8). It is extremely important that operators of fluoroscopic equipment be appropriately trained in the safe use of such machines and that all exposure to ionizing radiation is kept as low as reasonably achievable (9). Prior studies have shown that formal training programs regarding the safe and appropriate use of fluoroscopy during image-guided procedures can result in significantly reduced radiation doses (10). The purpose of this article is to present the results of a formal training program designed to prepare radiology residents at our institution to safely and efficiently perform FGLP. Finding or creating an appropriate model is an essential step in the development of any hands-on simulation-based training program. As part of the simulation-based LP training curriculum developed at our institution, we designed and created a custom lumbar spine phantom that is similar anatomically and fluoroscopically to human anatomy. This prototype FGLP phantom is inexpensive, robust, and durable and is designed to provide the visual and tactile simulation of FGLP necessary for resident training (11). This work evaluates whether the use of this phantom in combination with a short didactic training session can improve operator confidence and reduce procedure time and radiation dose while maintaining patient safety for FGLPs performed by resident trainees. MATERIALS AND METHODS Data and survey collection for this project was performed with institutional review board approval. Written consent was obtained from all resident trainees who participated in this study. The formal FGLP training program consisted of a 1 hour didactic curriculum with prelecture and postlecture surveys designed to assess knowledge of technique and anatomy, followed by multiple simulated LPs using the fluoroscopically accurate lumbar spine phantom. Before starting the didactic
portion of the training, each resident completed a baseline survey to assess his or her understanding of lumbar spine anatomy and fluoroscopic technique. The didactic lecture provided a review of the relevant anatomy, discussed indications and contraindications for performing FGLP, and outlined the risks and potential complications of the procedure. Pertinent anatomic and radiographic landmarks of the lumbar spine were reviewed, including the vertebral body, facet, pedicle, lamina, spinous process, intervertebral foramen, supraspinous ligament, interspinous ligament, ligamentum flavum, and dura. Common indications and risks for both diagnostic and therapeutic LP were discussed and the procedural differences outlined in detail. The didactic lecture (available in the Appendix) was given to each resident individually immediately before the start of their first neuroradiology rotation. After completion of the didactic training, the residents each performed 20 FGLP simulations over a 1-week time frame using our original lumbar spine phantom. The lumbar spine phantom was created from materials selected on their tactile and fluoroscopic similarity to bone and soft tissue. A lumbar spine model made of injectionmolded polyvinyl chloride (PVC) was used for the core of the phantom, and the soft tissue substitute was made with a thermoplastic polymer (Kraton D1111 K polystyrene-polyisoprene–polystyrene triblock thermoplastic polymer; Kraton Performance Polymers, Inc.). This synthetic tissue substitute was selected because it was inexpensive, colorless, radiolucent, and provided a tactile feel similar to that of human tissue. After mixing the thermoplastic polymer with mineral oil and heating until liquefied, the PVC lumbar spine model was suspended in the gelatin solution, and the phantom was allowed to cool. The creation process for the lumbar spine phantom required 10 hours to complete (including heating time to liquefy the polymer and cooling time to allow the polymer to set). This phantom has a total material cost of approximately US$148.00 and is anatomically accurate when viewed under fluoroscopy as shown in Figure 1. Further details related to the construction of this phantom can be found elsewhere (11). After 20 simulated LPs, residents were asked to subjectively rate confidence in their ability to perform an FGLP, both before and after completion of the training program (on a scale of 1–10; 1: very little confidence, 10: very confident). FGLP was performed with either personal or direct supervision from an attending physician, and informed consent was obtained from each patient before the start of the procedure. FGLPs were performed using sterile technique with the patient in either the prone or the prone oblique position, and intrathecal access was obtained primarily at the L3–L4 or L2–L3 levels. All prospective and retrospective procedures considered in this study were performed on one of two identical Philips Super 80 CO fluoroscopic units (Philips Healthcare, Andover, MA). Recorded data (for both retrospective and prospective procedures) included the type of procedure performed (diagnostic LP, myelogram, and so forth), indication for the procedure, primary operator (and additional operators in the case of unsuccessful attempts), and total fluoroscopy time (FT, minutes). 669
FAULKNER ET AL
Academic Radiology, Vol 22, No 5, May 2015
Figure 1. (a) Anterior–posterior view under live fluoroscopy of the fluoroscopically guided lumbar puncture (FGLP) training phantom used in this study. (b) Anterior– posterior view under live fluoroscopy of a human subject undergoing an FGLP.
Prospective procedural data from 114 LPs performed by the six post-graduate year 2 (PGY-2) residents (the prospective group) after completion of the simulation-based training program were compared to retrospective data from 514 LPs performed by 17 residents over the past 3 years who did not receive simulation-based training (the retrospective group). Both data subsets represent LPs performed by each resident during their first 1-month neuroradiology rotation. The retrospective data were composed of the first 15–25 LPs and/or myelograms performed by residents dating back to the 2010–2011 residency class representing each classes’ first rotation where multiple FGLPs were performed. The collected data points include the total FT, procedure type (ie, diagnostic LP vs. myelogram), unsuccessful LP attempts, and the clinical indication for each procedure. Clinical indications were grouped into the following nine subcategories: suspected meningitis, pseudotumor cerebri, subarachnoid hemorrhage, demyelinating disease, myelogram/cisternogram, intrathecal chemotherapy administration, normal pressure hydrocephalus, malignancy workup, and other. FTs and procedure success rate for each group (prospective and retrospective) were compared in aggregate, as well as by procedure type (diagnostic LP vs. intrathecal contrast administration for myelography). Each group was also compared based on failure rate, both in aggregate and by indication. Radiation dose and 670
the speed and efficiency at which residents performed the FGLP were evaluated using FT, whereas failure rate served as a measure of patient safety. Operator confidence was subjectively evaluated using the aforementioned survey after training with the spine phantom. Frequency statistics were performed on all categorical variables. Skewness and kurtosis statistics were used to assess normality for all continuous variables. Levene test was used to check for the assumption of homogeneity of variance. Independent samples t tests were used to compare resident groups on continuous outcomes. Mann–Whitney U tests were used when any statistical assumption was violated. Chi-square analyses were used to detect significant associations between resident groups and categorical outcomes. All analyses were conducted using SPSS, version 21 (IBM Corp., Armonk, NY), and statistical significance was assumed at a Bonferroni-corrected alpha value of .01. RESULTS Before the formal training program and before performing any FGLP procedures, the six PGY-2 residents who served as the prospective study cohort were asked to rate how confident they were in their ability to perform an FGLP. The average operator confidence was 3 of 10 on the initial survey
Academic Radiology, Vol 22, No 5, May 2015
SIMULATION-BASED EDUCATIONAL CURRICULUM FOR FGLP
Figure 3. Average fluoroscopy time for procedures performed for each indication. Error bars represent standard deviations.
Figure 2. Average fluoroscopy time for all procedures in aggregate, for all procedures with a diagnostic indication, and for all myelograms. Error bars represent standard deviations.
(1: very little confidence, 10: very confident). Average operator confidence increased greatly after training, climbing to 8.7 of 10 after completion of the didactic lecture and 20 simulated FGLPs with the lumbar spine phantom. Results from the pretraining and posttraining survey designed to gauge the residents’ knowledge of LP anatomy and procedural techniques also showed a large improvement, increasing from 38 of 54 questions answered correctly (70.4%) before training to 54 of 54 correct answers (100%) after completion of the training program. Clinical indications for FGLP procedures were subdivided into nine categories. The rate of unsuccessful FGLP and average FT for each group (prospective and retrospective) were compared in aggregate and by indication (Figs 2 and 3). The prospective cohort only performed a single examination for indication 8 (malignancy workup), and no procedures based on indication 9 (other), so comparisons could not be made for those indications. Average FT and standard deviation for the first seven indications are shown in Figure 3 and Table 1. There was a single unsuccessful FGLP in the 114 procedures performed by the prospective group (0 of 73 diagnostic LPs and 1 of 41 myelograms), and a total of seven unsuccessful FGLPs in the 514 procedures performed by the retrospective cohort (2 of 333 diagnostic LPs and 5 of 174 myelograms). The rate of unsuccessful FGLP was not statistically significant between the two groups, in aggregate or by indication (P = .56). There was a statistically significant reduction in average FT for the 114 procedures performed by the prospective group compared to the 514 procedures performed by the retrospective resident cohort (Table 2). This held true for all procedures
TABLE 1. Average Fluoroscopy Time (Minutes) for All Indications in Prospective versus Retrospective Study Cohorts
Indication Meningitis Pseudotumor SAH Demyelination Myelography Intrathecal chemotherapy NPH
Avg. Fluoro Time (Prospective), Minutes
Avg. Fluoro Time (Retrospective), Minutes
P Value
1.09 0.51 1.04 0.57 0.98 0.52
0.97 1.02 0.93 0.86 1.39 0.82
.87 .009* .8 .09 .001* .04*
1.03
0.91
.43
Avg., average; NPH, normal pressure hydrocephalus; SAH, subarachnoid hemorrhage. *Indicates a statistically significant difference between prospective and retrospective groups.
in aggregate, LPs for myelography, and all combined diagnostic procedures (all indications other than indication 5: myelogram/cisternogram). When subdivided by indication, there were statistically significant differences in average FT for indications 2 (pseudotumor), 5 (myelogram/cisternogram), and 6 (intrathecal chemotherapy administration). In aggregate, the prospective group showed a 25% reduction in average FT compared to the retrospective group (0.87 0.68 minutes prospective vs. 1.09 0.65 minutes retrospective; P = .002). This reduction in average FT remained when procedures were subdivided based on procedure type. There were 73 successful LPs performed for a diagnostic indication in the prospective group and 329 successful diagnostic LPs performed by the retrospective group (0.81 0.707 minutes prospective vs. 0.935 0.555 minutes retrospective; P = .002). Similarly, there were 40 successful myelograms performed by the 671
FAULKNER ET AL
Academic Radiology, Vol 22, No 5, May 2015
TABLE 2. Average Fluoroscopy Time (Minutes) for Prospective versus Retrospective Study Cohorts Avg. Fluoro Time Avg. Fluoro Time (Retrospective), P (Prospective), Minutes Value Minutes Diagnostic LP LP for myelogram All FGLP (total)
0.81 0.98 0.87
0.94 1.4 1.09
.002* .001* .002*
Avg., average; FGLP, fluoroscopically guided lumbar puncture; LP, lumbar puncture. *Indicates a statistically significant difference between prospective and retrospective groups.
prospective group and 164 successful myelograms performed by the retrospective group (0.978 0.619 minutes prospective vs. 1.387 0.728 minutes retrospective; P = .001). There were no statistically significant differences in success/failure rate between the two groups when procedures were subdivided based on indication.
DISCUSSION Radiology training programs have taught the importance of radiation safety and dose reduction for years, but this has become an even larger focus as the radiation exposure associated with medical imaging has continued to rise and public awareness has increased. FGLP is one of the more common image-guided procedures performed by radiologists. Prior studies have shown that the level of operator experience has a significant effect on the average FT associated with these procedures (2). One way to increase that level of experience without adversely impacting patient safety is through the use of hands-on simulation-based training programs (12). Our results support these previous findings (12) in the context of FGLP as, for many indications and in aggregate, FT was reduced without any statistically significant change in procedure success. We have designed an FGLP training curriculum that combines a didactic review of anatomy and procedural technique with hands-on simulation using a novel, fluoroscopically visible lumbar spine phantom. The LP phantom prototype created at our institution cost
