An MRI Analysis of the Pelvis to Determine the Ideal Method for Ultrasound-Guided Bone Marrow Aspiration from the Iliac Crest
TAKE-HOME POINTS
- There is an ideal angle and distance for optimization of a bone marrow harvest from the iliac crest.
- Ultrasound is a reliable technology that allows clinicians to accurately and consistently identify the PSIS and avoid neurovascular structures.
- This safe, reliable bone marrow aspiration technique can lower the risk of serious potential complications.
- The ideal angle does not differ significantly between sexes, but the safe distance a clinician can advance does.
- The PSIS should be considered a “table” as opposed to a protuberance.
RESULTS
The results are reported in the Table.
Table. Measurements of Patients Taken on Axial T2-Weighted Views of Lumbosacral MRI Scansa
Patient | SI Joint Angle (°) | Approach Angle (°) | PSIS Table Width (cm) | PSIS to Anterior Ilium Wall (cm) | Perpendicular Distance PSIS to Anterior Joint (cm) | Post Ilium Wall to SI Joint Width (cm) |
Males | ||||||
1 | 28.80 | 19.50 | 1.24 | 8.80 | 4.16 | 1.52 |
2 | 31.80 | 27.60 | 1.70 | 7.89 | 3.49 | 1.02 |
3 | 33.70 | 27.70 | 1.12 | 8.14 | 3.15 | 1.28 |
4 | 23.70 | 26.40 | 0.95 | 6.66 | 3.22 | 0.65 |
5 | 35.90 | 28.40 | 0.84 | 7.60 | 2.57 | 0.95 |
6 | 33.80 | 29.30 | 1.20 | 7.73 | 2.34 | 0.90 |
7 | 30.30 | 21.20 | 1.36 | 8.44 | 3.95 | 1.18 |
8 | 34.50 | 20.40 | 1.53 | 7.08 | 3.98 | 1.56 |
9 | 28.70 | 24.00 | 1.34 | 8.19 | 3.51 | 1.31 |
10 | 22.40 | 20.10 | 1.37 | 7.30 | 3.87 | 1.28 |
11 | 33.60 | 20.80 | 0.88 | 6.43 | 3.26 | 0.94 |
12 | 48.50 | 31.00 | 1.15 | 6.69 | 2.97 | 1.38 |
13 | 20.20 | 20.90 | 0.94 | 6.95 | 3.79 | 1.05 |
Averages | 31.22 | 24.41 | 1.20 | 7.53 | 3.40 | 1.16 |
Standard Deviation | 7.18 | 4.11 | 0.26 | 0.75 | 0.56 | 0.26 |
Females | ||||||
14 | 22.80 | 23.20 | 1.54 | 7.21 | 3.45 | 1.39 |
15 | 33.30 | 21.40 | 1.09 | 7.26 | 3.57 | 0.98 |
16 | 19.70 | 15.60 | 0.78 | 8.32 | 3.76 | 0.86 |
17 | 17.50 | 15.60 | 0.61 | 7.57 | 3.37 | 1.03 |
18 | 48.20 | 26.60 | 0.94 | 6.62 | 3.16 | 0.71 |
19 | 38.20 | 28.30 | 0.90 | 6.32 | 2.23 | 0.91 |
20 | 44.50 | 31.70 | 0.99 | 6.19 | 3.06 | 0.76 |
21 | 24.10 | 18.00 | 0.92 | 6.99 | 3.23 | 0.71 |
22 | 17.20 | 14.80 | 0.81 | 6.00 | 2.81 | 1.13 |
23 | 42.00 | 38.50 | 1.00 | 5.33 | 2.47 | 1.42 |
24 | 32.00 | 25.50 | 0.98 | 6.01 | 2.79 | 1.21 |
25 | 24.70 | 24.80 | 0.87 | 6.09 | 2.79 | 1.02 |
26 | 19.80 | 22.30 | 1.04 | 7.71 | 2.37 | 1.36 |
Averages | 29.54 | 23.56 | 0.96 | 6.74 | 3.00 | 1.04 |
Standard Deviation | 10.84 | 6.88 | 0.21 | 0.85 | 0.48 | 0.25 |
All patients Averages | 30.38 | 23.98 | 1.08 | 7.14 | 3.20 | 1.10 |
Standard Deviation | 9.05 | 5.57 | 0.26 | 0.88 | 0.55 | 0.26 |
aStatistical significance is denoted as P < .02.
Abbreviations: MRI, magnetic resonance imaging; PSIS, posterior iliac spine; SI, sacroiliac.
For the 13 males, the mean SI joint angle was 31.22° ± 7.18° (range, 20.20° to 48.50°). The mean approach angle was 24.41° ± 4.11° (range, 19.50° to 31.00°). The mean PSIS table width was 1.20 cm ± 0.26 cm (range, 0.84 cm to 1.70 cm). The mean distance from the PSIS to the anterior ilium wall was 7.53 cm ± 0.75 cm (range, 6.43 cm to 8.80 cm). The mean perpendicular distance from the PSIS table to the anterior ilium was 3.40 cm ± 0.56 cm (range, 2.34 cm to 4.16 cm). The mean minimum width of the ilium to the SI joint was 1.16 cm ± 0.26 cm (range, 0.65 cm to 1.56 cm).
For the 13 females, the mean SI joint angle was 29.54° ± 10.84° (range, 17.20° to 48.20°). The mean approach angle was 23.56° ± 6.88° (range, 14.80° to 38.50°). The mean PSIS table width was 0.96 cm ± 0.21 cm (range, 0.61 cm to 1.54 cm). The mean distance from the PSIS to the anterior ilium wall was 6.74 cm ± 0.85 cm (range, 5.33 cm to 8.32 cm). The mean perpendicular distance from the PSIS table to the anterior ilium was 3.00 cm ± 0.48 cm (range, 2.23 cm to 3.76 cm). The mean minimum width of the ilium to the SI joint was 1.04 cm ± 0.25 cm (range, 0.71 cm to 1.42 cm).
For the 26 total patients, the mean SI joint angle was 30.38° ± 9.05° (range, 17.20° to 48.50°). The mean approach angle was 23.98° ± 5.57° (range, 14.80° to 38.50°). The mean PSIS table width was 1.08 cm ± 0.26 cm (range, 0.61 cm to 1.70 cm). The mean distance from the PSIS to the anterior ilium wall was 7.14 cm ± 0.88 cm (range, 5.33 cm to 8.80 cm). The mean perpendicular distance from the PSIS table to the anterior ilium was 3.20 cm ± 0.55 cm (range, 2.23 cm to 4.16 cm). The mean minimum width of the ilium to the SI joint was 1.10 cm ± 0.26 cm (range, 0.65 cm to 1.56 cm).
There was a statistically significant difference between the male and female groups for the maximum distance the trocar can be advanced from the PSIS to the anterior ilium wall (P < .02), and a statistically significant difference for the PSIS table width (P < .02). There were no significant differences between the male and female groups for the approach angle, the SI joint angle, the perpendicular distance from the PSIS to the anterior ilium, and the minimum width of the ilium to the SI joint.
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