Abstract
Background:
The bone marrow biopsy procedure (BMP) is a frequently performed diagnostic procedure. The majority of BMP's in adults in the United States are performed on the posterior superior iliac spine (PSIS). Patients are generally assured that the BMP is a low-risk procedure, albeit momentarily painful. Major complications, include hemorrhage and hematomas, persistent pain, anesthesia reactions, pseudoaneurysms and fractures at the biopsy site. The reportedly low incidence of complications derive from retrospective surveys and case reports, but no prospective studies have been previously reported. The goal of this study was to delineate the actual patient risks of BMP, via the PSIS, when performed by Hematologists-in-Training (HIT's).
Methods:
Twenty five adult patients, 40 years of age and older, who were undergoing an elective BMP, were recruited and consented for this study. Exclusion criteria included lack of ability to consent, psychiatric issues, alcohol or drug abuse, bleeding disorders, pregnancy and lactation. All BMP's were performed, via the PSIS, by HIT's under the supervision of attending investigators. Based on prior safety studies, all biopsies targeted the anterior superior iliac spine (ASIS). 4-5 days after the BMP, all patients returned for a non-contrast pelvic CT, a questionnaire on pain and neurologic symptoms and hemoglobin/hematocrit (Hb/Hct) determination.
Results:
The average age of the 25 patients was 64 years, 44% were female and the average BMI was 25.7. By prespecified criteria, radiographic evidence of needle penetration outside the iliac bone was designated an adverse event. This was observed in 3 of 25 pelvic CT's (12%) where the needle track penetrated the posterior cortex of the ilium, into the sacro-iliac joint and the sacrum (Figures 1a, 1b and 1c). None of the 3 cases had excessive pain or evidence or unusual bleeding, and the pathology of the marrow did not differ between the sacral and the iliac biopsy specimens in terms of length, cellularity or fat content. CT analysis revealed that only a 9 degree deviation from the ASIS target could lead to sacral penetration (figure 1). Needle tracks were detected in the ilium in 5 additional patients. In 17 pelvic CT's, needle tracks were not identified. 2 of 25 patients reported prolonged moderate pain requiring analgesia after the BMP. Needle tracks were not visualized in either patient. No patient developed a significant hematoma or had an unexplained fall in Hb/Hct.
Conclusions:
The success and safety of the BMP depend upon correct identification of physical landmarks and correct angulation of the biopsy needle. A cadaver study at this institution showed that biopsy needle angulation towards the ASIS (Lateral Angulation Technique-LAT) was safer than the Traditional Angulation Technique where the needle is directed straight into the PSIS, perpendicular to the plane of the back. The present prospective study of the risks of BMP's by HIT's, supervised by attending investigators, revealed that 8% of the patients had prolonged pain requiring analgesia. Pelvic CT's 5 days after the BMP revealed that 12% of patients had penetration of the sacrum, although none had significant pain or blood loss and the pathology specimen was adequate. Analysis of CT's showed that only a 9 degree change in needle angulation can lead to penetration of the sacrum. We conclude that targeting the ASIS by the LAT approach, avoids inadvertent penetration of the sacrum. The LAT approach is probably safer for patients and may be a new standard of care for hematology training and practice. The high incidence of adverse events (20%) after BMP by HIT's calls for further research and consideration.
No relevant conflicts of interest to declare.
