Ultrasound-Guided Versus Fluoroscopy-Guided Sacroiliac Joint Intra-articular Injections in the Noninflammatory Sacroiliac Joint Dysfunction: A Prospective, Randomized, Single-Blinded Study

Archives of Physical Medicine and Rehabilitation journal homepage: www.archives-pmr.org Archives of Physical Medicine and Rehabilitation 2014;95:330-7

ORIGINAL ARTICLE

Ultrasound-Guided Versus Fluoroscopy-Guided Sacroiliac Joint Intra-articular Injections in the Noninflammatory Sacroiliac Joint Dysfunction: A Prospective, Randomized, Single-Blinded Study Haemi Jee, PhD,a Ji-Hae Lee, MD,b Ki Deok Park, MD,c Jaeki Ahn, MD, PhD,d Yongbum Park, MDd From the aDepartment of Health & Fitness Management, Namseoul University, Cheonan-Si; bDepartment of Radiology, Sanggye Paik Hospital, Inje University College of Medicine, Seoul; cDepartment of Rehabilitation Medicine, Gachon University of Medicine and Science, Gil Medical Center, Incheon; and dDepartment of Physical Medicine & Rehabilitation, Sanggye Paik Hospital, Inje University College of Medicine, Seoul, Republic of Korea.

Abstract Objective: To compare the short-term effects and safety of ultrasound (US)-guided sacroiliac joint (SIJ) injections with fluoroscopy (FL)-guided SIJ injections in patients with noninflammatory SIJ dysfunction. Design: Prospective, randomized controlled trial. Setting: University hospital. Participants: Patients (NZ120) with noninflammatory sacroiliac arthritis were enrolled. Intervention: All procedures were performed using an FL or US apparatus. Subjects were randomly assigned to either the FL or US group. Immediately after the SIJ injections, fluoroscopy was applied to verify the correct placement of the injected medication and intravascular injections. Main Outcome Measures: Treatment effects and functional improvement were compared at 2 and 12 weeks after the procedures. Results: The verbal numeric pain scale and Oswestry Disability Index improved at 2 and 12 weeks after the injections without statistical significances between groups. Of 55 US-guided injections, 48 (87.3%) were successful and 7 (12.7%) were missed. The FL-guided SIJ approach exhibited a greater accuracy (98.2%) than the US-guided approach. Vascularization around the SIJ was seen in 34 of 55 patients. Among the 34 patients, 7 had vascularization inside the joint, 23 had vascularization around the joint, and 4 had vascularization both inside and around the joint. Three cases of intravascular injections occurred in the FL group. Conclusions: The US-guided approach may facilitate the identification and avoidance of the critical vessels around or within the SIJ. Function and pain relief significantly improved in both groups without significant differences between groups. The US-guided approach was shown to be as effective as the FL-guided approach in treatment effects. However, diagnostic application in the SIJ may be limited because of the significantly lower accuracy rate (87.3%). Archives of Physical Medicine and Rehabilitation 2014;95:330-7 ª 2014 by the American Congress of Rehabilitation Medicine

Sacroiliac joint (SIJ) dysfunction is an underappreciated source of low back or buttock pain.1,2 Although low back pain often is thought of as idiopathic, specific pain generators can be identified

Supported by a 2013 research grant from Inje University, Gimhae, Korea. No commercial party having a direct financial interest in the results of the research supporting this article has conferred or will confer a benefit on the authors or on any organization with which the authors are associated.

in approximately 75% of those with chronic low back pain.3 Although there is no true criterion standard for the diagnosis of SIJ-originated pain, intra-articular (IA) fluoroscopy (FL)-guided injections have been considered to be the most plausible method of diagnosis.4 Image guidance of the SIJ IA injection seems to be important because of the complex anatomic nature of the joint, causing a low diagnostic accuracy when performed according to clinical judgment. Furthermore, with the accuracy rate of only

0003-9993/14/$36 - see front matter ª 2014 by the American Congress of Rehabilitation Medicine http://dx.doi.org/10.1016/j.apmr.2013.09.021

Ultrasound-guided approach in sacroiliac joint dysfunction 22% in patients, image guidance seems to be crucial in improving the success rate of the procedure.5 FL, computed tomography (CT), or magnetic resonance imaging has been recommended for the image-guided procedures.6-8 In recent years, ultrasound (US) has extended its application from a diagnostic tool to a highly accurate imaging tool in localizing injections.9,10 The advantages of US include exposure without radiation, real-time visualization of soft tissues, visualization of the needle tip advancement and local anesthetic spread relevant to the surrounding structures.11 The frequency of inadvertently injected intravascular steroid injections has been reported to range from 2.5% to 9% during CESI (cervical epidural steroid injections).12,13 Although aspirating the needle for blood may avoid intravascular drug injections, such a technique is neither sufficiently sensitive nor specific to significantly avoid an intravascular needle position. Color Doppler was used to avoid intravascular injections to overcome such a limitation. Yoon et al14 reported that vascular injection occurred if the injection flow was not detected as being mainly in the cephalad direction, and if the vascular flow was detected as having multicolored spectrums by the color Doppler. Using such identification method, Yoon14 reported a successful injection rate of 94%, and in 3 other unsuccessful cases, they reported that positional changes of the needle occurred after exchanging the syringe. Previous studies demonstrated that the US-guided SIJ injection method was feasibly applicable. They show similar success rates between the methods in terms of the extracapsular lesion and IA injections,15,16 with a 76.7% overall success rate for the USguided approach.17 However, previous studies had limitations in that they lacked either controls or subjects for elucidating clinical significance.15-17 Therefore, a randomized controlled trial to compare the accuracy, effectiveness, and safety of US imaging with a widely used imaging technique such as CT or FL seems necessary to elucidate the clinical significances in pain, functional improvement, and safety of the US-guided SIJ IA procedure. Hence, a prospective, randomized, single-blinded clinical trial was conducted to evaluate the short-term pain improvement resulting from US-guided SIJ IA injections, compared with that from FL-guided SIJ IA injections, in patients with noninflammatory SIJ dysfunction. In addition, patient satisfaction, the accuracy rate, functional improvement, and the incidence of intravascular injection were also assessed as secondary outcomes.

Methods Participants After obtaining approval and registering for a clinical trial with the institutional review board, 120 patients were enrolled into this prospective, randomized, single-blinded study. Between June 2011 and June 2012, 154 patients who had chronic low back pain (>3mo) without radiculopathy were evaluated for SIJ dysfunction. The

List of abbreviations: CT FL IA ODI SIJ US VNS

computed tomography fluoroscopy intra-articular Oswestry Disability Index sacroiliac joint ultrasound verbal numeric pain scale

www.archives-pmr.org

331 patients, referred by medical practitioners, neurosurgeons, or orthopedists for further diagnosis and treatment, received a diagnosis based on the medical history, image findings, and physical examinations. Inclusion criteria were as follows: (1) pain located laterally over the SIJ line; (2) positive findings on at least 1 of 3 provocation tests for SIJ paindGaenslen’s test, Patrick’s test, and Newton’s test; (3) negative response to Kemp’s test (pain provocation tests for sciatica); (4) no disorders in the hip joint; (5) no signs of lumbar radiculopathy; (6) radiographic degenerative joint disease; (7) and pain reduction >80% after diagnostic SIJ injection.18,19 Patients were excluded if they (1) had systemic inflammatory disease (ankylosing spondylitis, psoriatic arthritis, or Reiter syndrome); (2) were receiving anticoagulant therapy; (3) had uncontrolled diabetes, due to the adverse effects of steroids; (4) had prior allergic reactions to lidocaine or contrast media; (5) had suspected or diagnosed infection or avascular necrosis of the femoral head; (6) were in poor general health; (7) were unable to come to the hospital for follow-up visits; (8) had skin defects on the injection area; (9) had psychiatric problems that prevented completion of the study related questionnaires; (10) had prior injections within 3 months; (11) required anti-inflammatory medication other than acetaminophen; or (12) were undergoing supplementary therapeutic intervention during the study period that might affect the treatment effects such as additional peripheral injections or surgery.

Random sampling Participants were randomly assigned into either the US or FL group using a computer-generated randomization table. Individuals in both the US-guided SIJ IA injection group and the FL-guided SIJ IA injection group were to receive 0.5mL of nonionic contrast media (Omnipaque 300a) plus 2mL of the following mixture: 1.0mL of 0.5% lidocaine plus dexamethasone 10mg.

Baseline US technique All of the US examinations and the US- and FL-guided SIJ IA injection procedures were conducted by 1 physician (Y.P.) with more than 7 years of experience in both techniques. All treatments were performed as an outpatient procedure. Accuvix XQb with a linear probe at 6 to 12MHz for color Doppler mode was used as the US instrument.15,17 US scanning was performed by posteriorly placing the transducer with the patients in a prone position. First, a baseline US was performed to identify bony landmarks by depiction of the bony contours of the posterior superior iliac spine laterally and the spinous process of the fifth lumbar vertebra medially by axial transducer positioning. The transducer was moved caudad to depict the dorsal surface of the sacrum and the median and lateral sacral crest, the gluteal surface of the ilium, and the first posterior sacral foramen. From this level, the transducer was moved downward until the second posterior sacral foramen was visualized.16 Thorough observation of the vessels inside or around the posterior portions of the SIJ was conducted with a color Doppler US to avoid intravascular injections (fig 1).

US-guided SIJ IA injections The spinous process of the fifth lumbar vertebra was taken at the initial anatomic landmark. The transducer was moved caudad from the spinous process of the fifth lumbar vertebra over the

332

H. Jee et al

Fig 1 The baseline US technique. (A) Lower level of an SIJ, displayed by a short-axis sonogram. The tip of the needle (white arrow) can be visualized under the perpendicular US beam in the hypoechoic cleft of the SIJ dorsal margin (arrowhead). The white arrow indicates the perpendicular needle positioning. The white star indicates posterior sacral foramen 2. (B) Color Doppler sonogram shows vascularization (arrow) within the posterior portion of SIJ.

median sacral crest until the posterior sacral foramen 2 was visible.16 The posterior sacral foramen 2, the lateral sacral crest, the dorsal margin of the SIJ, and the iliac bone were visualized by moving the transducer laterally while orienting its lateral edge 20 cranially. After the delineation of the SIJ cleft, a 22-gauge 3.5-in spinal needle (Spinocanc) was led to the gap under US guidance in a freehand technique. If vessels were present inside the joint, the transducer was moved slightly cephalad or caudad until the vessels disappeared. With the needle held in the best achievable position, 0.1 to 0.2mL of noncontrast dye was injected, and the flow was observed using the color Doppler mode US. The spectrum was defined as being positive when a unidirectional flow (observed as 1 dominant color) of the solution was detected through the IA space without flows to other directions (observed as multiple colors) (fig 2).14 Two static images were taken for each injection, obtaining a total of 110 static images. Existence of an intravascular injection was verified by a blinded radiologist through a Picture Archiving and Communication System (PACS).

FL-guided SIJ IA injections The SIJ blocks were performed using the standard procedures.6,20 A 22-gauge 3.5-in spinal needle (Spinocan) was then inserted into the entrance of the SIJ, and the needle tip was angled slightly cephalad. The position of the needle was confirmed by injecting 0.1 to 0.2mL of nonionic contrast medium. A total of 110 static images were obtained to verify the occurrence of an intravascular injection, as in the US-guided method. The injected needle was adjusted upon the identification of the intravascular injection. After confirming the absence of any intravascular injection, the remaining 2.5mL of solution was injected into the SIJ.

Assessments Confirmation of the accuracy and intravascular injections Clinical analysis of the images was conducted in 2 stages. First, image analysis was conducted after injecting 0.1 to 0.2mL of the

contrast media, before injecting 2.5mL of the drug, to check for intravascular injection. Second, image analysis was conducted after injecting 2.5mL of the drug with contrast media, to check for the SIJ IA injection. After each SIJ IA injection, lateral, anteroposterior, and oblique radiographs were taken to confirm IA injections and the absence of intravascular injections. A radiologist (J.-H.L.) with more than 7 years’ experience with the musculoskeletal images and blinded to the injection methods, judged the radiographic results simultaneously for additional confirmation. Based on the imaging results obtained, we concluded whether the injected substances had reached the IA space and whether intravascular injection had occurred. The presence of any contrast material in the extraarticular space was defined as a “failure” (fig 3). Outcome measurements The primary outcome measurement was the verbal numeric pain scale (VNS),21 and the secondary outcome measurements were the 5-point patient satisfaction scale, Oswestry Disability Index (ODI), and occurrence of intravascular injections. The survey was conducted on each patient before the procedure and 2 and 12 weeks after the procedure.

Statistics The Pearson correlation and Mann-Whitney U methods were used to compare the characteristics of the 2 groups, such as their sex, age, body mass index, and duration of disease. In order to observe the treatment effects across time using the VNS and ODI, 2-way mixed analysis of variance was used. First, the interaction and main effects between the 2 variables, VNS and ODI, were analyzed. Post hoc analysis was conducted to assess the effects of treatment and time after observing the absence of interaction effect between the variables. Post hoc analysis of the difference in the main effect on the time variable was conducted by using 1-way repeated analysis of variance and the Bonferroni correction test. The patient postprocedure satisfaction levels, the incidence of intravascular injections, and complication rate were analyzed by www.archives-pmr.org

Ultrasound-guided approach in sacroiliac joint dysfunction

333

Fig 2 (A) US-guided SIJ IA injection. (B) Short-axis sonogram showing needle inside the SIJ (arrow). (C) Color Doppler image showing accurate IA injection. (D) Anteroposterior radiograph showing IA spread of the contrast agent after the SIJ IA injection.

www.archives-pmr.org

334

H. Jee et al

Fig 3

(A) Successful IA injection. (B) Visible leakage of nonionic contrast dye in the soft tissue.

Pearson correlation and Fisher exact tests. Since there were no studies available to help in estimating the sample size of the USguided SIJ IA approach, the sample size was calculated based on the significant pain relief of the lumbar radicular pain as the main assessment variable. For a 1-on-1 group comparison, 55 patients were estimated to be needed in each group.22 With allowance for a 10% attrition and noncompliance rate, 60 subjects were required. Previous studies23-25 of interventional techniques identified 50 to 60 patients as appropriate. Statistics were performed with SAS Enterprise Guide 4.1 (4.1.0.471),d with the significance level set at P<.025.

Results Participant flow A schematic illustration of patient flow is provided (fig 4). The study period with a 12-week follow-up lasted for a year. Among the 154 patients recruited, 34 patients were excluded and 120 patients were included in this study. Of these 120 patients, 5 patients in the US-guided group were excluded during follow-up because they received peripheral injections (hip) (nZ2) or took medications other than acetaminophen (nZ3), and 5 patients in the FL-guided group were excluded during follow-up because they received peripheral injections (2 hips, 3 knees). In total, 55 patients in the US-guided group and 55 patients in the FL-guided group were included in the study.

General characteristics of participants The mean ages  SD of the patients in the US- and FL-guided groups were 60.988.58 and 60.698.02 years, respectively, which were not significantly different. Significant differences

were not observed in the general characteristics of sex, body mass index, pain duration, and operation history (table 1).

Intravascular injections The injections into the joint cavity in 48 (87.3%) of 55 patients in the US-guided group were successful, as determined radiographically by the presence of contrast dye in the joint cavity. A significantly higher success rate was observed in the FL-guided group (98.2%) than in the US-guided group (P<.05). Of the 54 subjects who showed a positive Doppler spectrum change, confirmation was obtained in 48 subjects (88.9%) using FL, which revealed the presence of contrast dye in the SIJ space. Seven subjects, including 1 with a negative Doppler spectrum change and 6 with a positive spectrum change, showed contrast dye outside the SIJ space.

Treatment effects between the approaches Significant between-group differences were not observed in the ODI and VNS results before, and 2 and 12 weeks after the procedures (table 2). The VNS values significantly decreased in both groups, with continued treatment effects at 2 and 12 weeks after the procedures (see table 2). The ODI results significantly improved in both groups at 2 and 12 weeks after the procedures (see table 2). Similarly, there was no statistical difference between the 2 groups in the patient satisfaction index after 12 weeks. Pain in the periosteum, caused by needle irritation during the course of injection, was present in 4 patients in the FL-guided group and 1 patient in the US-guided group. In addition, leg weakness caused by sciatic nerve block was found in 2 and 3 patients in the FL- and US-guided groups, respectively. A statistical significance could not be observed because of a small number of cases. Serious complications such as advancement of the needle into the retropelvic area did not occur in either group. www.archives-pmr.org

Ultrasound-guided approach in sacroiliac joint dysfunction

Fig 4

Discussion The SIJ block, an IA injection procedure of local anesthetic into the SIJ, is thought to be a diagnostic test to confirm the presence of SIJrelated pain.25 The prevalence of SIJ dysfunction seems to be between 10% and 26.6%.26-28 The CT-guided procedure is already being used for the SIJ IA injections in routine clinical settings.7,29,30 Although the FL- and CT-guided techniques have the advantages of being safe and efficient, the disadvantage of radiation exposure limits their use.17 The US imaging method has been recently applied as an alternative method to place the needle into the SIJ space.15-17 Color Doppler ultrasonography was applied in order to augment the success rate and confirm IA in this study, because its application resulted in a significant success rate during similar epidural space injections in previous studies.6,19 Color Doppler imaging was reported to be suitable to monitor the accurate placement of the needle tip in caudal epidural injections.19 Of the 55 subjects in the US-guided group, 54 displayed a positive spectrum change via the contrast injection. Of these 54 subjects with positive spectrum changes, 48 IA space injections were confirmed by FL as being successful. Contrast dye was observed in the extracapsular space in the remaining 6 subjects because of the movement of the needle tip during the injection procedures. As for the accuracy rate of the IA injections, a significant difference was observed between the US- and FL-guided groups without an intergroup difference in the treatment effectiveness. The treatment effectiveness varied across the studies.15,18,31 This may be due to the diverse nature of the pain source. Many www.archives-pmr.org

335

Patient flow.

studies32,33 have demonstrated that the neural innervations and nociceptors are located not only in the joint capsule but also in the posterior ligamentous tissue, thus establishing them as additional sources of sacroiliitis-related pain. Because of the limited information regarding the medical history, physical examination, and imaging modalities, controlled FL- or CT-guided diagnostic block is the only method for definitive diagnosis or exclusion of the SIJ as the source of pain.34 SIJ IA injections may help to identify and relieve the pain of SIJ origin with the injection of anesthetic. The accuracy rate of the US-guided SIJ IA approach was 87.3%, which Table 1

General characteristics of patients

Characteristics Age (y) Sex Men Women BMI (kg/m2) Disease duration (mo) Operation (lumbar fusion)

US-Guided Approach FL-Guided Approach (nZ55) (nZ55) P 60.988.58 (32e73) 60.698.02 (41e77) .862 14 (25.5) 41 (74.5) 23.181.69 6.132.32

17 (30.9) 38 (69.1) 23.431.67 6.382.35

.525 .878 .777

14 (25.5)

15 (27.3)

.829

NOTE. Values are in mean  SD (minimumemaximum), n (%), mean  SD, or as otherwise indicated. Abbreviation: BMI, body mass index.

336

H. Jee et al

Table 2 Comparison of VNS and ODI at baseline and after the steroid injections Outcome Measure

Baseline

2wk After Injection

12wk After Injection

VNS US-guided approach 6.450.88 3.140.48* 2.560.44* FL-guided approach 6.530.86 3.140.47* 2.590.47* Total 6.490.87 3.140.48 2.580.46 ODI US-guided approach 46.747.44 26.265.08* 21.303.89* FL-guided approach 45.787.34 25.414.50* 20.533.44* Total 46.277.38 25.844.80 20.923.68 NOTE. Values are mean  SD. PZ.738, interaction effect on VNS (2way mixed ANOVA). PZ.773, main effect between treatments on VNS (2-way mixed ANOVA). PZ.972, interaction effect between treatment and time on ODI (2-way mixed ANOVA). PZ.888, main effect between treatments on ODI (2-way mixed ANOVA). Abbreviation: ANOVA, analysis of variance. * P<.025, comparison before and after the injection.

was less than the FL-guided SIJ IA approach (98.2%) in this study. Such results indicate a limitation of the US-guided approach as a diagnostic tool for SIJ IA block. Therefore, further studies are required to elucidate the usefulness of ultrasonography during the IA injection. Exact positioning of the needle tip in the SIJ during the procedure can be difficult for several reasons. First, even a small bony spur can compromise the visualization of the needle tip with an extensive posterior acoustic shadowing. In such instances, tilting of the US transducer may allow visualization of the US beam.16 Second, the out-of-plane approach used to visualize the needle with the US beam is known to have a limitation of following the selected target with the needle. The out-of-plane approach inserts the needle perpendicularly in the center and underneath the probe footprint to obtain a bright hyperechoic dot of the needle tip or shaft.35 Furthermore, it is difficult to approximate or distinguish between the needle tip and the shaft with the hyperechoic dot shown on the US image. In order to resolve needle positioning problems, hydrolocalization was used by Bloc et al.36 This maneuver is performed by first moving the inserted needle and observing the changes in the surrounding tissue. The appearance of a small hypoechoic or anechoic pocket was further observed after a small fluid injection. Vascularization around the SIJ was being fed by the branches of sacral arteries37 and was seen in 34 of 55 patients. Among these 34 patients, 7 had vascularization only inside the joint, 23 had it only around the joint, and 4 had it both inside and around the joint. Three cases of intravascular injections were found in only the FL group. A few studies38,39 have used the US-guided method for identifying vascularization in patients with active sacroiliitis. In one of the studies, vessels located in the pathway of the needle placed correctly under FL alone were safely avoided with a color Doppler.38 Color Doppler provided information to move the transducer slightly cephalad or caudad until the vessels disappeared and were placed in the upper lesion relative to the SIJ. Yoon et al14 suspected intravascular injection and relocated the needle tip if a vascular flow was detected by the Doppler with a multicolored spectrum, even without a detection in the cephalad direction. Such a method was applied in this study, and intravascular injection did not occur in 54 subjects with a positive Doppler spectrum change.

Study limitations The present study has several limitations. First, the study results may have reflected the experience of 1 practitioner, which may have limited the generalizability of the study findings. The treatment procedures were conducted by the same physician, who had more than 5 years of experience in both methods. Second, although the experienced clinician may have controlled the location of the needle probe, the free-hand technique used for IA delivery may have affected the results of the study. Third, the mid- and long-term effects should be evaluated in the future based on the results of the short-term effects. Fourth, the study was not conducted as a double-blinded, controlled study. It is difficult to conduct a double-blinded, controlled study with nontraditional modalities such as US or FL. However, the pain, function, and satisfaction scores were evaluated by a researcher unfamiliar with the injection methods in order to avoid research bias. Fifth, this study used a single diagnostic block to diagnose SIJ dysfunction, and the false-positive rate of the uncontrolled injections was reported to be 38%.40 In order to avoid an increase in the false-positive rate due to the usage of the single diagnostic block method, the diagnostic response for patients with SIJ dysfunction was limited to >80%. Finally, the US-guided method was performed and limited to patients with a body mass index of less than 30kg/m2. Visualization of small vessels may be very challenging, especially in obese patients. These limitations should be reflected in designing a more practical approach.

Conclusions The US-guided SIJ IA injection approach showed similar improvement in pain relief and function, and similar patient satisfaction scores as the FL-guided approach, without the risk of radiation exposure. Therefore, the US-guided SIJ IA injection method may be a reliable imaging modality for therapeutic SIJ IA injections. Advantages such as convenience and being free of a radiation hazard make US preferable to FL. However, the US-guided approach may still have limitations in comparison to the FL-guided approach as far as accuracy is concerned. Therefore, the US-guided SIJ IA injection approach may have a diagnostic limitation in SIJ dysfunction. Further studies are required to safely use US during the SIJ IA injections.

Suppliers a. Omnipaque 300; GE Healthcare, Carrigtwohill Co. Cork, Ireland. b. Accuvix XQ; Medison, Samsung Medison Building, 1003 Daechi-dong Gangnam-gu, Seoul, Korea, 135-851. c. Spinocan; B. Braun, Postfach 1120, 34209 Melsungen, Germany, 34212. d. SAS Enterprise Guide 4.1 (4.1.0.471); SAS Institute Inc, 100 SAS Campus Dr, Cary, NC 27513.

Keywords Fluoroscopy; Injections; Ultrasonography

Rehabilitation;

Sacroiliac

joint;

www.archives-pmr.org

Ultrasound-guided approach in sacroiliac joint dysfunction

Corresponding author Yongbum Park, MD, Department of Physical Medicine & Rehabilitation, Sanggye Paik Hospital, Inje University College of Medicine, Sanggye 7 dong 761-7, Nowon-gu, 139-707, Seoul, Korea. E-mail address: [email protected].

References 1. Daum WJ. The sacroiliac joint: an underappreciated pain generator. Am J Orthop (Belle Mead NJ) 1995;24:475-8. 2. LeBlanc KE. Sacroiliac sprain: an overlooked cause of back pain. Am Fam Physician 1992;46:1459-63. 3. Verrills P, Vivian D. Interventions in chronic low back pain. Aust Fam Physician 2004;33:421-6. 4. Foley BS, Buschbacher RM. Sacroiliac joint pain: anatomy, biomechanics, diagnosis, and treatment. Am J Phys Med Rehabil 2006;85:997-1006. 5. Rosenberg JM, Quint TJ, de Rosayro AM. Computerized tomographic localization of clinically-guided sacroiliac joint injections. Clin J Pain 2000;16:18-21. 6. Dussault RG, Kaplan PA, Anderson MW. Fluoroscopy-guided sacroiliac joint injections. Radiology 2000;214:273-7. 7. Bollow M, Braun J, Taupitz M, et al. CT-guided intraarticular corticosteroid injection into the sacroiliac joints in patients with spondyloarthropathy: indication and follow-up with contrast-enhanced MRI. J Comput Assist Tomogr 1996;20:512-21. 8. Pereira PL, Gunaydin I, Trubenbach J, et al. Interventional MR imaging for injection of sacroiliac joints in patients with sacroiliitis. AJR Am J Roentgenol 2000;175:265-6. 9. Reach JS, Easley ME, Chuckpaiwong B, Nunley JA II. Accuracy of ultrasound guided injections in the foot and ankle. Foot Ankle Int 2009;30:239-42. 10. Chen CP, Wong AM, Hsu CC, et al. Ultrasound as a screening tool for proceeding with caudal epidural injections. Arch Phys Med Rehabil 2010;91:358-63. 11. Narouze SN, Vydyanathan A, Kapural L, Sessler DI, Mekhail N. Ultrasound-guided cervical selective nerve root block: a fluoroscopycontrolled feasibility study. Reg Anesth Pain Med 2009;34:343-8. 12. Price CM, Rogers PD, Prosser AS, Arden NK. Comparison of the caudal and lumbar approaches to the epidural space. Ann Rheum Dis 2000;59:879-82. 13. Stitz MY, Sommer HM. Accuracy of blind versus fluoroscopically guided caudal epidural injection. Spine (Phila Pa 1976) 1999;24:1371-6. 14. Yoon JS, Sim KH, Kim SJ, Kim WS, Koh SB, Kim BJ. The feasibility of color Doppler ultrasonography for caudal epidural steroid injection. Pain 2005;118:210-4. 15. Hartung W, Ross CJ, Straub R, et al. Ultrasound-guided sacroiliac joint injection in patients with established sacroiliitis: precise IA injection verified by MRI scanning does not predict clinical outcome. Rheumatology (Oxford) 2010;49:1479-82. 16. Klauser A, De Zordo T, Feuchtner G, et al. Feasibility of ultrasound-guided sacroiliac joint injection considering sonoanatomic landmarks at two different levels in cadavers and patients. Arthritis Rheum 2008;59:1618-24. 17. Pekkafahli MZ, Kiralp MZ, Basekim CC, et al. Sacroiliac joint injections performed with sonographic guidance. J Ultrasound Med 2003;22:553-9. 18. Murakami E, Tanaka Y, Aizawa T, Ishizuka M, Kokubun S. Effect of periarticular and intraarticular lidocaine injections for sacroiliac joint pain: prospective comparative study. J Orthop Sci 2007;12:274-80. 19. Slipman CW, Jackson HB, Lipetz JS, Chan KT, Lenrow D, Vresilovic EJ. Sacroiliac joint pain referral zones. Arch Phys Med Rehabil 2000;81:334-8. 20. Bogduk N. Practice guidelines for spinal diagnostic and treatment procedures: sacroiliac joint blocks. Kentfield: International Spine Intervention Society; 2004.

www.archives-pmr.org

337 21. Hartrick CT, Kovan JP, Shapiro S. The numeric rating scale for clinical pain measurement: a ratio measure? Pain Pract 2003;3:310-6. 22. Browner WS, Cummings SR, Hulley SB. Estimating sample size and power. In: Hulley SB, Cummings SR, Browner WS, Grady D, Hearst N, Newman TB, editors. Designing clinical research: an epidemiologic approach. 2nd ed. Philadelphia: Lippincott, Williams & Wilkins; 2001;65-84. 23. Manchikanti L, Cash KA, McManus CD, Pampati V, Smith HS. Preliminary results of a randomized, equivalence trial of fluoroscopic caudal epidural injections in managing chronic low back pain: part 1ddiscogenic pain without disc herniation or radiculitis. Pain Physician 2008;11:785-800. 24. Manchikanti L, Singh V, Cash KA, Pampati V, Damron KS, Boswell MV. Preliminary results of a randomized, equivalence trial of fluoroscopic caudal epidural injections in managing chronic low back pain: part 2ddisc herniation and radiculitis. Pain Physician 2008;11: 801-15. 25. Manchikanti L, Singh V, Cash KA, Pampati V, Datta S. Preliminary results of a randomized, equivalence trial of fluoroscopic caudal epidural injections in managing chronic low back pain: part 3dpost surgery syndrome. Pain Physician 2008;11:817-31. 26. Pang WW, Mok MS, Lin ML, Chang DP, Hwang MH. Application of spinal pain mapping in the diagnosis of low back paindanalysis of 104 cases. Acta Anaesthesiol Sin 1998;36:71-4. 27. Maigne JY, Aivaliklis A, Pfefer F. Results of sacroiliac joint double block and value of sacroiliac pain provocation tests in 54 patients with low back pain. Spine (Phila Pa 1976) 1996;21:1889-92. 28. Irwin RW, Watson T, Minick RP, Ambrosius WT. Age, body mass index, and gender differences in sacroiliac joint pathology. Am J Phys Med Rehabil 2007;86:37-44. 29. Braun J, Bollow M, Seyrekbasan F, et al. Computed tomography guided corticosteroid injection of the sacroiliac joint in patients with spondyloarthropathy with sacroiliitis: clinical outcome and followup by dynamic magnetic resonance imaging. J Rheumatol 1996;23:659-64. 30. Pulisetti D, Ebraheim NA. CT-guided sacroiliac joint injections. J Spinal Disord 1999;12:310-2. 31. Luukkainen RK, Wennerstrand PV, Kautiainen HH, Sanila MT, Asikainen EL. Efficacy of periarticular corticosteroid treatment of the sacroiliac joint in non-spondylarthropathic patients with chronic low back pain in the region of the sacroiliac joint. Clin Exp Rheumatol 2002;20:52-4. 32. Bowen V, Cassidy JD. Macroscopic and microscopic anatomy of the sacroiliac joint from embryonic life until the eighth decade. Spine (Phila Pa 1976) 1981;6:620-8. 33. Sakamoto N, Yamashita T, Takebayashi T, Sekine M, Ishii S. An electrophysiologic study of mechanoreceptors in the sacroiliac joint and adjacent tissues. Spine (Phila Pa 1976) 2001;26:E468-71. 34. Dreyfuss P, Dreyer SJ, Cole A, Mayo K. Sacroiliac joint pain. J Am Acad Orthop Surg 2004;12:255-65. 35. Souzdalnitski D, Lerman I, Halaszynski TM. How to improve needle visibility. In: Narouze SN, editor. Atlas of ultrasound-guided procedures in interventional pain management. 1st ed. New York: Springer; 2011;35-75. 36. Bloc S, Mercadal L, Dessieux T, et al. The learning process of the hydrolocalization technique performed during ultrasound-guided regional anesthesia. Acta Anaesthesiol Scand 2010;54:421-5. 37. Williams PL, Warwick R, Dyson M, Bannister LH. Grays anatomy. 37th ed. London: Churchill Livingstone; 1989. 38. Arslan H, Sakarya ME, Adak B, Unal O, Sayarlioglu M. Duplex and color Doppler sonographic findings in active sacroiliitis. AJR Am J Roentgenol 1999;173:677-80. 39. Klauser AS, De Zordo T, Bellmann-Weiler R, et al. Feasibility of second-generation ultrasound contrast media in the detection of active sacroiliitis. Arthritis Rheum 2009;61:909-16. 40. Schwarzer AC, Aprill CN, Derby R, Fortin J, Kine G, Bogduk N. The false-positive rate of uncontrolled diagnostic blocks of the lumbar zygapophysial joints. Pain 1994;58:195-200.