Association Of Lumbar Puncture With Spinal Hematoma In Patients With And Without Coagulopathy

Key PointsQuestionWhat is the risk of spinal hematoma after lumbar puncture in patients with coagulopathy? FindingsIn this Danish registry-based cohort study that included 64730 patients undergoing 83711 individual lumbar punctures, the overall 30-day risk of spinal hematoma was 0.20% among patients without coagulopathy at the time of the procedure and 0.23% among patients with coagulopathy. MeaningAlthough potentially limited by bias due to physicians selecting relatively low-risk patients for lumbar puncture, these findings provide estimates of the risk of spinal hematoma that may inform decision-making about lumbar puncture.ImportanceCoagulopathy may deter physicians from performing a lumbar puncture. ObjectiveTo determine the risk of spinal hematoma after lumbar puncture in patients with and without coagulopathy. Design, Setting, and ParticipantsDanish nationwide, population-based cohort study using medical registries to identify persons who underwent lumbar puncture and had cerebrospinal fluid analysis (January 1, 2008-December 31, 2018; followed up through October 30, 2019). Coagulopathy was defined as platelets lower than 150x10(9)/L, international normalized ratio (INR) greater than 1.4, or activated partial thromboplastin time (APTT) longer than 39 seconds. ExposuresCoagulopathy at the time of lumbar puncture. Main Outcomes and MeasuresThirty-day risk of spinal hematoma. Risks were provided as numbers and percentages with 95% CIs. Secondary analyses included risks of traumatic lumbar puncture (>300x10(6) erythrocytes/L after excluding patients diagnosed with subarachnoid hemorrhage). Adjusted hazard rate ratios (HRs) were computed using Cox regression models. ResultsA total of 83711 individual lumbar punctures were identified among 64730 persons (51% female; median age, 43 years [interquartile range, 22-62 years]) at the time of the procedure. Thrombocytopenia was present in 7875 patients (9%), high INR levels in 1393 (2%), and prolonged APTT in 2604 (3%). Follow-up was complete for more than 99% of the study participants. Overall, spinal hematoma occurred within 30 days for 99 of 49526 patients (0.20%; 95% CI, 0.16%-0.24%) without coagulopathy vs 24 of 10371 patients (0.23%; 95% CI, 0.15%-0.34%) with coagulopathy. Independent risk factors for spinal hematoma were male sex (adjusted hazard ratio [HR], 1.72; 95% CI, 1.15-2.56), those aged 41 through 60 years (adjusted HR, 1.96; 95% CI, 1.01-3.81) and those aged 61 through 80 years (adjusted HR, 2.20; 95% CI, 1.12-4.33). Risks did not increase significantly according to overall severity of coagulopathy, in subgroup analyses of severity of coagulopathy by pediatric specialty or medical indication (infection, neurological condition, and hematological malignancy), nor by cumulative number of procedures. Traumatic lumbar punctures occurred more frequently among patients with INR levels of 1.5 to 2.0 (36.8%; 95% CI, 33.3%-40.4%), 2.1 to 2.5 (43.7%; 95% CI, 35.8%-51.8%), and 2.6 to 3.0 (41.9% 95% CI 30.5-53.9) vs those with normal INR (28.2%; 95% CI, 27.7%-28.75%). Traumatic spinal tap occurred more often in patients with an APTT of 40 to 60 seconds (26.3%; 95% CI, 24.2%-28.5%) vs those with normal APTT (21.3%; 95% CI, 20.6%-21.9%) yielding a risk difference of 5.1% (95% CI, 2.9%-7.2%). Conclusions and RelevanceIn this Danish cohort study, risk of spinal hematoma following lumbar puncture was 0.20% among patients without coagulopathy and 0.23% among those with coagulopathy. Although these findings may inform decision-making about lumbar puncture by describing rates in this sample, the observed rates may reflect bias due to physicians selecting relatively low-risk patients for lumbar puncture.This cohort study uses Danish registry data to assess the risk of spinal hematoma following lumbar puncture in patients with vs without coagulopathy (platelets <150 x 10(9)/L, INR >1.4, or APTT >39 seconds).