Upper Sacral Morphology Related to Iliosacral Screw Fixation in Korean

PURPOSE: To evaluate upper sacral morphology and anatomy of safe zone related to iliosacral screw fixation in Korean. MATERIALS AND METHODS: 100 patients performed pelvis 3D CT scan were evaluated. We used 16 channel CT and analyzed reconstructed image (shaded-surface display, transparent image and reformat image). RESULT: The angle between superior aspect of S1 body and iliac cortical density is 27.3°, between anterior cortical line of S1,2 body and horizontal plane 24.6°, and between superior aspect of S1 body and horizontal plane is 39.7°. The axis of S1, S2 pedicle is 32.5° and 15.6° toward anteromedial. The area of S1 pedicle according to sagittal plane and sagittal-oblique axis is 310.7 mm2 and 384.8 mm2. Also, S2 pedicle area is increased 163.1 mm2 to 188.4 mm2. The average depth of ala indentation is 5.1 mm and the maximal value is 9.5 mm. Distinct upper sacral dysplasia is 22%, transitional form is 32%. CONCLUSION: We measured Korean upper sacrum with 3D-CT, found out dysplasia come up to 54%. Considering the frequency of dysplasia, the investigation of anatomy and technique is essential to sacroiliac screw insertion.

Ultrasonographic Evaluation of Ischial Bursitis

PURPOSE: The objective of this study was to evaluate the findings of ultrasonography (US) in patients withis-chial bursitis. MATERIALS AND METHODS: Our study included 27 patients (mean age 62 years) who underwent US fora painful mass or tenderness in the buttock area. In six of these 27, serous fluid was obtained by needleaspiration, and in five cases, bursal excision permitted histologic confirmation. The other sixteen patients werefollowed up for one or two months with only NSAID medication; all showed some improvement or remission of symptoms. Using a 5-10 MHz linear array probe, US examination was performed while the patient was lying facedown. US images were analyzed with regard to location and size of the lesions, thickness of cyst wall, thepres-ence of internal septa or mural nodules, echogenicity of the cyst wall, fluid content, internal septa,compressibility by a probe, and Doppler signals within the cyst wall. RESULTS: In all 27 patients, ischialbursitis was located superficially to ischial tuberosity. Lesion size(maximum diameter) was 1.5-7(mean 3.8)cm, andthe cyst wall was 0.2-0.8cm thick. Internal septa and mural nodules were seen in 12 cases (44%) and 13 cases(48%), respectively. The cyst wall was identifiable in 21 cases (78%), appearing as a single layer with lowechogenicity (n=10) or with high echogenicity (n=1); it also appeared as two (n=6) or three (n=4) layers ofdifferent echogenicities. When internal septa were present, fluid within the cyst was low echoic in 59% of cases,high echoic in 30%, and of mixed echogenicity (so-called compartmentalization) in 15%. In all cases, the cystbecame deformed, when compressed by a probe. In all patients who underwent doppler examination, some vascularitywas found within the cyst wall. CONCLUSION: US helped to detect ischial bursitis; US findings were thin-walled cystic lesion located superficially to ischial tuberosity, with or without internal septa and mural nodules, andeasy compressibility.