Training Hematology and Medical Oncology Fellows in Performing Bone Marrow Biopsies- a Quality Improvement Initiative

Background Bone marrow biopsies are frequently performed in the evaluation of many benign and malignant hematologic disorders and occasionally utilized in the diagnostic evaluation of fever of unknown origin. ^{1 2}

Guidelines for bone marrow biopsy samples vary. A size of 20mm for lymphoma , 15 mm for myeloproliferative disease , 16 mm for malignant neoplasms in general is considered to be a rough guide³. Bone marrow samples can be altered during the processing which may lead to shrinkage of up to 25% from the size obtained ⁵. Awareness and strict adherence to recommended bone marrow biopsy sample sizes seems limited. Type of bone marrow biopsy needle such as manual or motorized needles, operator skill and patient body habitus lead to variability in size, hemodilute aspirates and crush artifacts⁵.

Suboptimal samples due to inadequate size or aspiration artifact can lead to delays in diagnosis, need for repeat procedures with physical, emotional and financial consequences⁴ .

In our institution, we undertook a quality improvement initiative to improve upon the sample sizes and minimize artifacts of bone marrow biopsies and herein we report the results of this project.

Methods: We collected data from the outpatient bone marrow biopsy clinic on all the bone marrow biopsies done by a class of hematology and oncology fellows between the months of July 2021 and January 2022 . Data was collected for 70 bone marrow biopsy encounters. Each encounter was analyzed for size , type of artifact if present, patient diagnosis, age, gender, BMI, number of attempts and use of sedation to assess meaningful correlations and potential contributing factors.

We then performed individual one on one intervention sessions with each fellow participating in the project to review their individual operator data and discuss areas of improvement. A best practices handout with the steps to a successful biopsy and common pitfalls with useful tips was given to all the fellows and was placed in the bone marrow biopsy clinic for reference.

A post procedure checklist was added and included a measuring aid to ensure that the bone samples were of the desired size which allowed practitioners to be more aware of the quality of their collected samples and intervene again if needed to get better samples in the same encounter.

A survey was also utilized to understand the personal experiences and knowledge barriers that may be contributing to inferior outcomes and allow for anonymous feedback.

Data was then collected again over a 6-month period post intervention to screen for improvement in percentage of adequate biopsies, average size of sample obtained and presence of artifacts.

Results: Data obtained pre-intervention showed a 39.4% inadequate samples. The average bone marrow biopsy size was 1.2 cm, 95% CI ( 1.05- 1.35). There was a 22.5% aspiration artifact in the tested samples along with 16.9% and 1.4% fragmentation and crush artifacts respectively.

Interestingly the size of adequate samples in this pre-intervention cohort of biopsies was 1.23cm 95% CI (1.04-1.42) , indicating that the percentage of inadequate samples was mostly influenced by high degree of artifacts in the obtained samples.

In addition, patient age, BMI and diagnosis did not correlate with percentage of inadequate samples suggesting operator skill and technique as the main factor in determining outcomes.

Of the 49 post intervention samples analyzed, the average size of the sample was 1.2cm, 95% CI ( 1.03- 1.37) which was similar to the pre intervention samples . but there was a difference in the size of the adequate samples at 1.43cm 95% CI ( 1.27-1.59) , . 8.1% of samples had aspiration artifact . 8.1%of samples had fragmentation. Overall, this intervention resulted in a decrease in the inadequate sample rate from 39.4% to 26.5%

Conclusion: Bone marrow biopsies are an important part of investigating a wide array of diseases , personal skill and experience are important factors in determining adequacy of samples , there is merit behind a combined approach of individualized feedback along with tools such as post-procedure checklists for self-evaluation to improve the quality of collected bone marrow biopsy samples in new Hematology and Oncology fellowship trainees. Novel approaches such as utilization of image guidance or ultrasound may be worth exploring to further improve sampling yield.

No relevant conflicts of interest to declare.