Technical feasibility of an angle-free ultrasound-assisted approach for challenging lumbar puncture in complex spinal anatomy: a two-patient case series
- 1Department of Anesthesiology, The First Affiliated Hospital, Sun Yat-sen University
- 2Department of Anesthesiology, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Southern Medical University
- 3Department of Anesthesiology and Perioperative Medicine, Mayo Clinic
Abstract
Background Lumbar puncture is particularly challenging in patients with abnormal spinal anatomy, such as severe scoliosis or obesity. Conventional ultrasound‑assisted neuraxial techniques have two fundamental limitations: inaccurate projection of the probe’s geometric center onto the skin when the probe is tilted and difficulty replicating the exact probe angle during needle insertion. These limitations often result in multiple needle passes, prolonged procedure time, and increased patient discomfort and complication risk. We developed an ultrasound‑assisted technique designed to standardize needle trajectory by eliminating the need for lateromedial and craniocaudal angulation through positional adjustment and report its technical feasibility in a case series. Case presentation This angle‑free technique was applied to two patients with spinal muscular atrophy requiring repeated intrathecal nusinersen injections. Both patients had extremely complex spinal anatomy, including high body mass index (30 and 35.1 kg/m²) and severe scoliosis (Cobb angles 90° and 83°). The technique followed a four‑step protocol: (1) planning using available imaging; (2) ultrasound‑guided positioning; (3) marking the needle insertion point; and (4) inserting the needle parallel to the floor and perpendicular to the bed edge without lateromedial or craniocaudal angulation. All 22 procedures (11 per patient) were completed successfully without persistent neurological complications. First‑attempt success rates were 81.8% in Case 1 and 100% in Case 2, with first‑pass success rates of 45.5% and 54.5%, respectively. Longitudinal data across sequential procedures showed a rapid decreasing trend in both the number of needle passes and needling time. Conclusions This angle‑free ultrasound‑assisted lumbar puncture appears technically feasible for patients with complex spinal anatomy. The structured “4P” protocol (planning, positioning, perpendicular, and parallel) may offer a practical guide for clinical adoption. The observed reduction in needle passes and needling time may suggest potential learnability, but this finding is preliminary and requires confirmation. Further investigation is warranted to definitively establish its learning curve.
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BibTeX
@article{wang2026technical,
title = {{Technical feasibility of an angle-free ultrasound-assisted approach for challenging lumbar puncture in complex spinal anatomy: a two-patient case series}},
author = {Xuan Wang and Yijun Luo and Xiaolong Zhang and Xiaolin Lu and Daniel A. Diedrich and Chanyan Huang and Ying Xiao},
journal = {BMC Anesthesiology},
year = {2026},
month = jul,
doi = {10.1186/s12871-026-04079-1},
url = {https://doi.org/10.1186/s12871-026-04079-1},
note = {CC BY},
}
RIS
TY - JOUR
TI - Technical feasibility of an angle-free ultrasound-assisted approach for challenging lumbar puncture in complex spinal anatomy: a two-patient case series
AU - Xuan Wang
AU - Yijun Luo
AU - Xiaolong Zhang
AU - Xiaolin Lu
AU - Daniel A. Diedrich
AU - Chanyan Huang
AU - Ying Xiao
PY - 2026
DA - 2026/07/01
JO - BMC Anesthesiology
DO - 10.1186/s12871-026-04079-1
UR - https://doi.org/10.1186/s12871-026-04079-1
AB - Background Lumbar puncture is particularly challenging in patients with abnormal spinal anatomy, such as severe scoliosis or obesity. Conventional ultrasound‑assisted neuraxial techniques have two fundamental limitations: inaccurate projection of the probe’s geometric center onto the skin when the probe is tilted and difficulty replicating the exact probe angle during needle insertion. These limitations often result in multiple needle passes, prolonged procedure time, and increased patient discomfort and complication risk. We developed an ultrasound‑assisted technique designed to standardize needle trajectory by eliminating the need for lateromedial and craniocaudal angulation through positional adjustment and report its technical feasibility in a case series. Case presentation This angle‑free technique was applied to two patients with spinal muscular atrophy requiring repeated intrathecal nusinersen injections. Both patients had extremely complex spinal anatomy, including high body mass index (30 and 35.1 kg/m²) and severe scoliosis (Cobb angles 90° and 83°). The technique followed a four‑step protocol: (1) planning using available imaging; (2) ultrasound‑guided positioning; (3) marking the needle insertion point; and (4) inserting the needle parallel to the floor and perpendicular to the bed edge without lateromedial or craniocaudal angulation. All 22 procedures (11 per patient) were completed successfully without persistent neurological complications. First‑attempt success rates were 81.8% in Case 1 and 100% in Case 2, with first‑pass success rates of 45.5% and 54.5%, respectively. Longitudinal data across sequential procedures showed a rapid decreasing trend in both the number of needle passes and needling time. Conclusions This angle‑free ultrasound‑assisted lumbar puncture appears technically feasible for patients with complex spinal anatomy. The structured “4P” protocol (planning, positioning, perpendicular, and parallel) may offer a practical guide for clinical adoption. The observed reduction in needle passes and needling time may suggest potential learnability, but this finding is preliminary and requires confirmation. Further investigation is warranted to definitively establish its learning curve.
SN - 1471-2253
ER -