Detection of spine structures with Bioimpedance Probe (BIP) Needle in clinical lumbar punctures
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Lumbar puncture is a relatively safe procedure, but some serious, even fatal, complications can occur. Needle guidance can increase puncture accuracy, decrease the number of attempts, and make the procedure easier. We tested the feasibility of a bioimpedance-based tissue-sensing technology for needle guidance in clinical use. The Bioimpedance Probe (BIP) Needle has a removable BIP stylet enabling measurement of bioimpedance spectra during the procedure. The BIP Needle is connected to a measurement device that uses tissue-classification software, and the device provides audiovisual feedback when it detects cerebrospinal fluid (CSF). We performed spinal anesthesia with the BIP Needle in 45 patients. The device performance and needle tip location were verified by an experienced anesthesiologist confirming CSF leakage. The device detected CSF in all cases (sensitivity of 100 %). Six cases with false detections lowered the specificity to 81 %, but in practice, most of these were easy to differentiate from true detections because their duration was short and they occurred during backward movement of the needle. The epidural spectrum differentiated as fatty tissue from surrounding tissues, but the ligamentum flavum was not clearly detectable in the data. The BIP Needle is a reliable tool for detecting CSF in lumbar puncture. It can make the puncture procedure smoother, as repeated CSF flow tests are avoided. The correct needle tip location is immediately detected, thus unnecessary needle movements close to spinal nerves are prevented. Physicians could benefit from the information provided by the BIP Needle, especially in patients with obesity or anatomic alterations.
KeywordsSpinal anesthesia Bioimpedance Needle guidance Monitoring Cerebrospinal fluid Epidural
We thank M Rorarius, Assoc Prof em, who was involved in designing the present clinical study. We also thank all participating patients and study nurses. Injeq Ltd provided BIP Needles and bioimpedance analyzer for the study.
This research was supported by the European Union through the European Regional Development Fund in frames of the research center CEBE and competence center ELIKO, and also by Estonian Research Council (IUT-19-11-2014).
Compliance with ethical standards
Conflict of interest
S. H., J. K., and K. K. are employees of Injeq Ltd, K. K. is a stakeholder of Injeq Ltd.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.
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