Ultrasound-guided lumbar puncture improves success rate and efficiency in overweight patients

Approximately 400,000 diagnostic lumbar punctures (LPs) are performed by neurologists yearly in the United States. There has been a transition from neurologists performing >40% of LPs 2 decades ago to now <15% of the time. High body mass index (BMI) is one of the key obstacles of LP for neurology residents, and the success rates drop to 58% when BMI is >35 kg/m².

A prospective intervention study was conducted from March 2017 to March 2018 at an academic medical center. Patients were divided into ultrasound-guided LP or conventional LP. The primary outcome was the success rate of LP. The secondary outcome was the parameters regarding LP performance, the patients' feedback after procedures, and the residents' feedback about the learning modules.

Eighty-two patients were enrolled with inclusion criteria of age >18 years, BMI ≥25 kg/m², and able to give written informed consent. The ultrasound-guided LP group showed higher success rate (92.7% vs 68.3%, p < 0.05) and less duration of time (17.02 vs 37.63 minutes, p < 0.05) compared with the conventional LP group. It also showed advantages of decreased trials of needle insertions and redirections and reduced pain levels perceived by patients.

This study suggests that using ultrasound to localize before LP could increase the LP success rate and improve other related LP outcomes in the overweight populations. Our study also provides evidence that brief, targeted teaching modules are feasible and effective for ultrasound-guided LP training.

This study provides Class III evidence that for patients with BMI ≥25 kg/m² undergoing LP, ultrasound guidance increases the LP success rate.