Predicting difficult and traumatic lumbar punctures

Objective The objective of this study is to determine if visual and tactile inspection of the spine is useful in the prediction of a difficult or traumatic lumbar puncture (LP). Design This was a prospective, observational, cohort study conducted in the emergency department (ED) on patients who were undergoing an LP. Physicians prospectively completed a structured data form that included information about the patient, number of prior LPs performed, their assessment of the LP difficulty, and the number of needlesticks required. A “difficult” LP and a “traumatic” tap were defined a priori. χ2, t tests, and regression were used as appropriate; an independent statistician performed the statistical analysis. Setting The study was conducted at an urban university teaching hospital with an annual ED census of approximately 48 000 patients between November 1, 2002, and June 1, 2003. Patients The study population included a convenience sample of patients undergoing LP in the ED. Results Of the 148 patients enrolled, LP was difficult in 47 (32%) patients and traumatic in 23 (16%) patients. The percentage of patients that did not have a visible spine was significantly higher in the difficult and traumatic groups (P < .05). Among patients where the physician was unable to visualize the spine, there were significantly more difficult LPs (P < .05). Conclusion It may be possible to predict which patients will have difficult or traumatic LPs before performing the procedure. Simple bedside assessments of spine visibility and palpability may assist in planning the approach to an LP in patients.