Tehran University of Medical Sciences International Journal of Hematology-Oncology and Stem Cell Research 2008-2207 13 3 2019 07 10 146 152 José Carlos Jaime-Pérez Department of Hematology, Internal Medicine Division, Dr. José E. González University Hospital of the School of Medicine of the Universidad Autónoma de Nuevo León, Monterrey, Mexico Guillermo Sotomayor-Duque Department of Hematology, Internal Medicine Division, Dr. José E. González University Hospital of the School of Medicine of the Universidad Autónoma de Nuevo León, Monterrey, Mexico Patrizia Aguilar-Calderón Department of Hematology, Internal Medicine Division, Dr. José E. González University Hospital of the School of Medicine of the Universidad Autónoma de Nuevo León, Monterrey, Mexico Lorena Salazar-Cavazos Department of Hematology, Internal Medicine Division, Dr. José E. González University Hospital of the School of Medicine of the Universidad Autónoma de Nuevo León, Monterrey, Mexico David Gómez-Almaguer Department of Hematology, Internal Medicine Division, Dr. José E. González University Hospital of the School of Medicine of the Universidad Autónoma de Nuevo León, Monterrey, Mexico 2018 12 08 2019 04 14 Background: Lumbar puncture (LP) is a hematology procedure that can require repeated attempts leading to traumatic LP (TLP), which has been related to the central nervous system (CNS) relapse. LP success can depend on the size and anatomy of the patient and the skill of the hematologist. The main objective was to determine the influence of body mass index (BMI) on LP outcomes. Materials and Methods: Adults with lymphoid malignancies requiring LP were included prospectively over one year; hematology residents performed most procedures. A 22-gauge Quincke needle was employed. Comparison between non-traumatic vs. traumatic LPs according to BMI, CNS relapse, and residents’ year was performed. Results: Fifty-four patients with a mean age of 31.5±15.57 years were included. Diagnosis was Acute Lymphoblastic Leukemia-B (74%), Acute Lymphoblastic Leukemia-T (13%) and Non-Hodgkin Lymphoma (13%). 227 LPs were performed, 121 (53.3%) successful, 98 (43.2%) traumatic, 11 (11.2%) TLPs were macroscopically detectable and 87 (88%) microscopic; 8 (3.5%) were dry-taps. Median time between punctures was 11 days (1-202). Median BMI was 25 (22.8-39.6). Main indication for LP was prophylactic (74.5%); 39.2% were performed by first-year, 35.2% by second-year, 19.6% by third-year hematology residents. No difference (p = 0.145) for a TLP was found among residents. A BMI ≥30 (p = 0.040), non-palpable intervertebral space (p = 0.001) and more than one attempt (p = 0.001) were significant for TLP. TLP was not associated with CNS relapse (p = 0.962). Conclusion: Obesity predicted a TLP. A traumatic puncture did not increase the risk of CNS relapse at one-year follow-up. https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/view/1039 https://ijhoscr.tums.ac.ir/index.php/ijhoscr/article/download/1039/795