Ultrasound-guided lumbar puncture as a diagnostic aid to reduce number of attempts and complication rates

Abstract

Ultrasound-guided lumbar puncture (LP) could be beneficial in situations where anatomical landmarks are difficult to identify. There is some evidence that it is associated with increased success rates and procedural ease. Its effect on complication rates has not been explored. This mixed retrospective-prospective case-control study over 6 months compares unguided (retrospective data, n = 28) and ultrasound-guided LPs (prospective data, n = 23) in non-emergency patients. Presence of factors making LPs difficult (DF) i.e. BMI ≥30 kg/m2, scoliosis and previous lumbar spinal surgery were recorded. There was a significant difference in attempt rates between unguided and ultrasound-guided LPs (median 2 vs. 1; p = 0.01) with complication rates of 50% and 26.1%, respectively ( p = 0.15). In a subgroup analysis, complication rates were significantly different in those with DF (76.9%, unguided LPs (n = 13) vs. 33.3%, ultrasound-guided LPs (n = 12); p = 0.03), with an absolute risk reduction of complications of 43.6% (NNT of 2.3) in ultrasound-guided vs. unguided LPs. In those with DF, the back pain rates were significantly reduced (53.8% unguided LPs vs. 8.3% ultrasound-guided LPs; p = 0.02). In the ultrasound-guided LP group, there was no blood contaminated cerebrospinal fluid samples, whereas this occurred in 14% of unguided LPs. Ultrasound-guidance significantly reduced the number of LP attempts. In those with DF, the use of ultrasound significantly reduced post-procedural complication, particularly back pain. Ultrasound-guidance during LP procedures can reduce patient discomfort and encourage patient safety, thereby improving clinical practice.