Lumbar punctures in thrombocytopenic children with cancer.
INTRODUCTION
Lumbar punctures (LP) in patients presenting thrombocytopenia are linked to the possibility of bleeding and spinal hematomas. The minimum platelet count required for the safe performance of spinal procedures is still under discussion. Children with some oncology diseases require routinely lumbar punctures; such patients often present thrombocytopenia, making this group an ideal population to study the association between lumbar puncture in thrombocytopenic patients and complications.


OBJECTIVES
To determine the platelet count of oncology children undergone lumbar punctures and the occurrence of spinal hematomas.


METHOD
Observational longitudinal study. It included a retrospective analysis of electronic medical records of oncology patients submitted to LP for intrathecal chemotherapy between January 2004 and October 2011, carried out at the 'Instituto de Medicina Integral Prof. Fernando Figueira (IMIP)', Recife, Brazil.


RESULTS
We evaluated 9088 lumbar punctures performed in 440 patients. The platelet count distribution before lumbar punctures was as follows: 25 punctures had zero to 10,000 platelets per mm(3), 67 punctures had between 10,000 and 20,000 platelets per mm(3), 88 had between 20,000 and 30,000 platelets per mm(3), 92 punctures had between 30,000 and 40,000 platelets per mm(3), 107 punctures had between 40,000 and 50,000 platelets per mm(3), and 729 punctures had between 50,000 and 100,000 platelets per mm(3). In this series, the incidence of bloody tap was 16.9% (1112 lumbar punctures of 6552 had more than ten erythrocytes). No complications were observed.


CONCLUSIONS
Even in thrombocytopenic patient, an epidural hematoma would be a relatively rare complication following lumbar puncture. Despite the large number of punctures performed on patients with platelet counts below 100,000 mm(-3) (n = 1108), further studies are necessary in order to determine a lower safe platelet count threshold for the performance of lumbar punctures in healthy patients undergoing neuraxial anesthesia.