Landmark vs. Ultrasound-Assisted Bone Marrow Biopsy Procedure Study

Overview

Bone marrow biopsies are routinely performed by the Medicine Bedside Procedure Team service at Froedtert Hospital. Typical indications for inpatient bone marrow biopsies include evaluations for cytopenia, leukemia, lymphoma, myelodysplastic syndrome, or plasma cell dyscrasia. The bone marrow is sampled from the posterior iliac crest, ideally by drilling into the posterior superior iliac spine (PSIS). The Arrow® OnControl® Powered Bone Access System is utilized for this process. Most frequently, the location of the PSIS is estimated by using palpation of landmarks, such as the lateral iliac crests, spinous processes, sacrum, and the PSIS itself. Additionally, when using lidocaine to anesthetize the site, the needle is maneuvered to locate the most superficial portion of the PSIS, confirming the optimal drill anchor site. The correct direction/angle of the drill is estimated based on the orientation of the patient, typically directing it perpendicular to the coronal plane. Palpating landmarks to identify the posterior superior iliac spine is often difficult due to patient body habitus. Ultrasonography allows for accurate identification of the PSIS. It allows the clinician to pinpoint the best entry point in the skin and optimal drill angle to drive the needle perpendicular to the coronal plane. Furthermore, it allows the clinician to measure the distance from the skin to the PSIS, ensuring the drill bit is anchored onto the correct site. The benefits of an ultrasound approach have not been well documented. Therefore, this study will seek to provide evidence of benefits, or lack thereof, in using ultrasound for bone marrow biopsies. This will be achieved using a two-arm, open-label, randomized study design which will compare patient outcomes, as measured by pain assessment, bone marrow biopsy procedure metrics, and bone marrow biopsy sample quality, between subjects that have undergone the procedure using either the control landmark palpation method or ultrasound-assisted technique to properly identify the PSIS.

2.1 Hypothesis The Investigators will be working under the overarching hypothesis that using ultrasound to locate the PSIS and determine the appropriate drilling angle will provide better outcomes and disease diagnosis for patients undergoing the bone marrow biopsy procedure. 2.2 Primary Objective • Determine whether incorporating ultrasound into a routine bone marrow biopsy improves the adequacy of core sample for diagnosis. 2.3 Secondary Objectives * Determine whether incorporating ultrasound into a routine bone marrow biopsy improves the adequacy of aspirate smears. * Determine whether incorporating ultrasound into a routine bone marrow biopsy improves patient pain assessment. * Establish a correlation between number of drill attempts and patient pain. * Examine whether the ultrasound-assisted bone marrow biopsy procedure reduces drill attempts. * Determine if ultrasound-assisted bone marrow biopsy reduces patient risk, as measured by the number of complications post-procedure. 2.4 Primary Endpoint • Adequacy of core samples for diagnosis between landmark and ultrasound-assisted arms: The proportion of adequate, suboptimal, and inadequate bone marrow biopsy samples, as measured by the overall length of evaluable marrow space using hematoxylin and eosin (H\&E) stained slides, will be compared between the landmark and ultrasound-assisted cohorts. Cores containing ≥1.5 cm of evaluable marrow space will be considered adequate, 0.5-1.5 cm suboptimal, and \<0.5 cm inadequate. 2.5 Secondary Endpoints * Adequacy of aspirate smears between landmark and ultrasound-assisted arms: The proportion of adequate, suboptimal, and inadequate aspirate smears, as measured by the presence of aggregate marrow spicules and overt presence of marrow cells, will be compared between the landmark and ultrasound-assisted cohorts. Aspirate smears with at least one 200x field in aggregate marrow spicules will be considered adequate. Those with marrow spicules but less than one 200x field in aggregate, or those without marrow spicules but with overt presence of marrow cells on initial scanning, will be considered suboptimal. Those without marrow spicules and without overt presence of marrow cells on initial scanning will be considered inadequate. * Patient pain assessment between landmark and ultrasound-assisted arms: The proportion of patients with a pain score of seven or more, determined 12 to 24 hour post-procedure, will be compared between the landmark and ultrasound-assisted cohorts. Pain assessment will be scored for each patient using the 0-10 point visual analog scale. * Correlation between number of drill attempts and patient pain: A correlation coefficient (Pearson's or Spearman's) will be determined by using the number of drill attempts and the pain scores collected during a 12- to 24-hour post-procedure window for all patients regardless of the arm. The number of drill attempts needed to obtain bone marrow for each patient will be recorded immediately following the procedure. Patient pain assessment will be scored using the 0-10 point visual analog scale. * Number of drill attempts between landmark and ultrasound-assisted arms: The mean number of drill attempts needed will be compared between the landmark and ultrasound-assisted cohorts. The number of drill attempts needed to obtain bone marrow for each patient will be recorded immediately following the procedure. * Number of complications between landmark and ultrasound-assisted arms: The mean number of complications within +30 days post-procedure will be compared between the landmark and ultrasound-assisted cohorts. The specific type and number of complications will be recorded and tabulated, respectively, for each patient within +30 days post-procedure.