The spectroscopic information obtained with the optical spinal needle is complementary to fluoroscopic images, and it could potentially allow for reliable identification of the epidural space during needle placement.

No abstract

The effectiveness of peripheral nerve blocks is highly dependent on the accuracy at which the needle tip is navigated to the target injection site. Even when electrical stimulation is utilized in combination with ultrasound guidance, determining the proximity of the needle tip to the target region close to the nerve can be challenging. Optical reflectance spectroscopy could provide additional information about tissues that is complementary to these navigation methods. We demonstrate a novel needle stylet for acquiring spectra from tissue at the tip of a commercial 20-gauge needle. The stylet has integrated optical fibers that deliver broadband light to tissue and receive scattered light. Two spectrometers resolve the light that is received from tissue across the wavelength range of 500-1600 nm. In our pilot study, measurements are acquired from a postmortem dissection of the brachial plexus of a swine. Clear differences are observed between spectra acquired from nerves and those acquired from adjacent tissue structures. We conclude that spectra acquired with the stylet have the potential to increase the accuracy with which peripheral nerve blocks are performed.

we have to make all possible efforts in order to reduce CA puncture in the actual clinical situation, because the IJV and CA overlap more frequently in pregnant compared with nonpregnant women. Increases in body weight or body mass index, chronological measurements, such as early in pregnancy, at term, and postpartum, in the same individuals may be useful in predicting the rate of this variation. Furthermore, the effect of uterine displacement in pregnant women on the size of the IJV may be interesting to investigate.