Eliko impedance spectroscopy for safer lumbar punctures

Eliko in collaboration with Injeq has developed a new generation smart needle for real-time tissue identification using our patented bioimpedance spectroscopy.

Physicians traditionally rely on their experience to guide the needle in the human body during lumbar puncture procedures. In spinal anaesthesia, for example, the physician often doesn’t reach the spinal canal on the first attempt. In a clinical study done by Injeq, the duration of the spinal puncture varied between 9 seconds and 19 minutes. Repetitive probing costs valuable time and severely increases the risk of complications such as bacterial infections and headaches.


The smart needle is the results of joint development between Eliko and Injeq, a Finnish MedTech company. The needle consists of a bioimpedance probe located inside the needle tip and a measurement device based on Quadra impedance spectroscopy. The new device guides the physician to the right location in the body using audio signals, thus improving the safety and efficiency of spinal anesthesia, intrathecal injections and other invasive medical procedures.


The need for reliable tissue identification guided Injeq to choose bioimpedance spectroscopy as a well-recognised technology for measuring biological objects. Bioimpedance characterises different tissues by their unique frequencies based on their electrical conductivity.

In the initial stages of product development, Injeq used an in-house impedance measurement technology. However, it lacked the spectral range and real-time functionality needed for the smart needle. The application dictates that the technology needs to enable real-time discrimination between the tissue types. The challenge for Injeq was to find a bioimpedance spectroscopy device that was simple to use but still provided a complex enough spectrogram for high accuracy results.

How Eliko Helped

When Injeq approached Eliko in 2011 it was instantly a good match. Our technology is best suited for applications where the measurement time is limited or the object is changing rapidly. The real-time feedback mechanism of a spinal tap procedure requires that data be analysed constantly as the physician is moving the needle forward in the body. This means that the tissue identification algorithm needs to handle continuous multi-frequency data with a high sample rate of hundreds of times per second.

“We tested other devices and in the end Quadra worked best for us.” Kai Kronström, Injeq CEO

Quadra enabled Injeq to develop a bioimpedance spectroscopy-based tissue recognition technology at the tip of a hypodermic needle. The smart needle is based on Eliko’s patented bioimpedance spectroscopy device and includes jointly developed tissue recognition algorithms for each specific medical application.


Injeq technology and products can be adapted for use in different clinical applications. A completed clinical study in rheumatology has confirmed that the smart needle is suitable for intra-articular injections. Another study in spinal anesthesia aims to assess the performance of the smart needle in detecting the cerebrospinal fluid inside the subarachnoid space in the spinal canal. Quadra is clearly able to identify the correct tissues as the clinical studies have shown excellent results so far

“What we appreciate is how Eliko was willing to do the custom work that was necessary for our device.” Kai Kronström, Injeq CEO

Around 100 million lumbar punctures are performed annually and time variance between physicians in performing the procedure can be more than 100 times. The minutes that it takes to find the spinal canal accumulate and cost valuable time and money as well as causing unnecessary discomfort for the patient. Quadra technology is what enables the smart needle to identify different tissue types in real time and helps doctors to perform more accurate and faster medical procedures.

The cooperation between Eliko and Injeq is ongoing with potential new applications in liver cancer diagnostics.