Presented at the 2012 AAPM Annual Meeting « Back

Ultrasound-Guided Ischial Bursa Injection

Jason M. Erickson, DO MSPT, erickson.jason@mayo.edu¹, Stephen Wisniewski, MD¹, (1) Mayo Clinic, Rochester, Minnesota

Introduction: Due to the proximity of the ischial bursa to the sciatic nerve and other important surrounding structures, the use of radiologic guidance may assist in minimizing potential neurovascular complications associated with injection of the bursa. We compared (using ultrasound) the distance from the skin to the ischium and from the ischium to the sciatic nerve in asymptomatic volunteers when the hip is in two different injection positions: a neutral position and when the hip is flexed 90 degrees. Materials and Methods: Twenty volunteer subjects were recruited. Ultrasound measurements were obtained of the shortest distance from the skin to the ischial tuberosity and from the ischium to the sciatic nerve with the subjects situated in each of two positions Results: There were statistically significant differences related to position (prone versus lateral decubitus with the hip flexed to 90 degrees) for the distance from the ischial tuberosity to the skin and from the ischial tuberosity to the sciatic nerve. The sciatic nerve moved laterally an average of 140.2 mm in the lateral decubitus hip flexed position. Conclusions: Based on the results of our study, the lateral decubitus position with the affected hip flexed to 90 degrees results in a potentially safer needle trajectory to the ischial bursa. This position allows for the sciatic nerve to move laterally, away from the ischial tuberosity and overlying bursa. We therefore recommend that physicians consider this injection technique to maximize patient safety and comfort while decreasing the risk of iatrogenic trauma to the sciatic nerve. References: 1)Hitora T, Kawaguchi Y, Mori M, Imaizumi Y, Akisue T, Sasaki K, Yamada E, Yamamoto T. Ischiogluteal bursitis: a report of three cases with MR findings. Rheumatol Int 2009; 29:455-458. 2)Swartout R, Compere EL. Ischiogluteal Bursitis: The Pain in the Arse. JAMA, 1974; 227(5):551-552. 3)Van Meighem IM, Boets A, Sciot R, Van Breuseghem IV. Ischiogluteal bursitis: an uncommon type of bursitis. Skeletal Radiol 2004; 33:413-416. 4)Cho KH, Lee SM, Lee YH, Suh KJ, Kim SM, Shin MJ, Jang HW. Non-infectious ischiogluteal bursitis: MRI findings. Korean J Radiol 2004; 5:280-286. 5)Volk M, Gmeinwieser J, Hanika H, Manke CH, Strotzer M. Ischiogluteal bursitis mimicking soft-tissue metastasis from a renal cell carcinoma. Eur Radiol 1998; 8:1140-1141. 6)Mills GM, Baethge BA. Ischiogluteal Bursitis in Cancer Patients: An Infrequently Recognized Cause of Pain. Am J Clin Oncol 1993; 16(3):229-231. 7)Akisue T, Yamamoto T, Marui T, Hitora T, Nagira K, Mihune Y, Kurosaka M, Fujita I, Matsumoto K. Ischiogluteal Bursitis: Multimodality Imaging Findings. Clinical Orthopaedics and Related Research January 2003; 406:214-217. 8)Butcher AD, Salzman KL, Lillegard WA. Lower Extremity Bursitis. American Family Physician 1996; 53:2317-2324. 9)Kim SM, Shin MJ, Kim KS, Ahn JM, Cho KH, Chang JS, Lee SH, Chhem RK. Imaging features of ischial bursitis with an emphasis on ultrasonography. Skeletal Radiol 2002; 31:631-636. 10)Jackson DW, Evans NA, Thomas BM. Accuracy of needle placement into the intra-articular space of the knee. Journal of Bone & Joint Surgery 2002; 84-A(9):1522-7.

Funding: Mayo Clinic department of PM&R resident research fund