Injection granulomas. Intramuscle or intrafat?
N. Haramati, R. Lorans, M. Lutwin and R. N. Kaleya
Department of Radiology, Albert Einstein College of Medicine, Bronx, NY.
OBJECTIVES: Intramuscular injection is a commonly used route of parenteral
drug administration. We studied the fat vs muscle location, the depth of
calcified buttock granulomas, and the thickness of subcutaneous fat. Data
were assessed with respect to the length of a needle commonly used in
intramuscular buttock injections. DESIGN: Three hundred thirty-eight
sequential pelvic computed tomographic scans were studied. Subcutaneous fat
thickness was measured for each patient at the upper outer quadrant of the
buttock. The location and depth of each calcified granuloma were also
recorded. SETTING: Tertiary care academic teaching hospital. RESULTS: One
hundred sixty-four calcified granulomas were found in 67 patients. One
hundred fifty-two of these granulomas were in fat and 12 were in muscle;
this was statistically significant using a single-sample binomial
distribution (P < .001;95% confidence interval, 0.04 to 0.13). The mean
(+/- SD) subcutaneous fat thickness at the upper outer quadrant of the
buttock was 5.0 +/- 1.9 cm, with female patients having a mean subcutaneous
fat thickness of 5.7 +/- 1.8 cm vs 4.4 +/- 1.7 cm for male patients.
CONCLUSIONS: The finding that buttock subcutaneous fat thickness exceeds
the length of the most commonly used needle for intramuscular buttock
injection (3.8 cm), together with the preponderance of calcified granulomas
found in the fat of female patients, suggests that the currently used
injection technique may not be therapeutically optimal. We suggest that
longer needles be used for intramuscular buttock injections in adults.
