Epidural cannula

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Tuohy needle, size 16G, with a matching peridural catheter in the background

As epidural cannula ( epidural , Periduralnadel or cannula ) are cannulas referred to this are, due to their particular shape, the epidural space to puncture (peridural) and through the injection of anesthetics and / or the introduction of an epidural catheter, an epidural (synonym epidural) to cause. The variant used almost exclusively today is the Tuohy cannula (after Edward Tuohy , American anesthetist, 1908–1959). There are modified versions that enable simultaneous spinal anesthesia ( combined spinal and epidural anesthesia ).

Development and construction

After August Bier had described the first clinical application of spinal anesthesia in 1899 , the French radiologist Jean-Anthanase published Sicard. the first report of a puncture of the epidural space, which he had performed at the level of the sacrum to relieve chronic pain in this area.

Tip of the Tuohy needle, detail
In comparison, a port needle with a Huber point

One-time injections into the epidural space at the level of the lumbar spine are documented in 1921 by the Spaniard Fidel Pagés and in 1933 by the Italian Archile Mario Dogliotti (1897–1966). Continuous blockages were carried out by the Romanian gynecologist Eugene Aburel (1931) and the American Robert A. Hingson. (from 1942). They used just for this purpose spinal needles by Barker , with which the introduction of a catheter (thin were initially urinary catheter used for this purpose) was impractical and difficult, with correspondingly low success rates of the process.

Edward Tuohy , former military doctor and anesthetist at the Mayo Clinic , developed the puncture cannula later named after him in the 1940s. Crucial changes were the curved tip of the needle and a stylet that prevented skin cells from being carried over. By bending the cannula it was now possible to bring the inserted catheter into an arrangement parallel to the spinal cord, which increased the success rates. Tuohy did not come up with this principle, however, but adopted the invention of the dentist Ralph L. Huber (1890–1953). He had developed the curved cannula tip in order to reduce the pain in the injection of blood vessels and tissue trauma (today's port needles also have such a tip). Tuohy neglected Huber when describing his modified needle, which is criticized today. He also did not recognize the possibility of inserting a pain catheter into the epidural space with the cannula, but was rather interested in continuous anesthesia in the spinal space. The epidural application was first popularized by the Cuban anesthetist Cuban Manuel Martinez Curbelo .

The Tuohy needle was later modified many times, including by Charles E. Flowers , Robert Hustead , OB Crawford , Jess Weiss and Jürgen Sprotte . The aim of these was better practicability and less tissue trauma, among other things to reduce the high rate of post -puncture headache that accidental puncture of the spinal space entails.

application

Main article: Epidural anesthesia
Schematic representation of epidural anesthesia (B), compared to spinal anesthesia (A)

The epidural anesthesia is performed sitting or lying on your side under sterile conditions. The choice of the height of the puncture site on the patient's spine is primarily dependent on the intended use (at the level of the lumbar spine in obstetrics , at the level of the thoracic spine for procedures on the chest or abdomen). After disinfection and local anesthesia of the skin, the Tuohy needle is inserted into the patient's back between two spinous processes of the spine . The needle penetrates the ligamentous structures of the spine and, after passing through them , reaches the epidural space . During the process, a syringe connected to the Tuohy needle is continuously applied slightly overpressure; After reaching the epidural space, in contrast to the needle position in the ligaments, liquid or air can easily be injected, whereby the correct positioning of the cannula tip can be identified ( loss-of-resistance method ). Anesthetics (mostly local anesthetics , opioids ) can then be injected through the cannula or, if necessary, an epidural catheter inserted through which active ingredients can be administered (temporarily or permanently) as required. Due to the curvature of the cannula (which is specifically desired for this purpose), the peridural catheter is inserted parallel to the spinal cord , mostly in the direction of the head (cranial), as shown in red in the diagram below under "B".

literature

Individual evidence

  1. A. Bier: Experiments on the cocainization of the spinal cord. In: Dtsch Z Chir. 51, 1899, pp. 361-368.
  2. ^ A. Sicard: Les injections medicamenteuses extra-durales par voie sacrococcygienne. In: Compt Rend Soc De Biol. 53, 1901, pp. 396-398.
  3. F. Pagés: Anesthesia metamerica. In: Rev Esp Chir. 3, 1921, pp. 3-30.
  4. AM Dogliotti: A new method of block: segmental peridural spinal anesthesia. In: The American Journal of Surgery . 20, 1933, pp. 107-118.
  5. E. Aburel: L'anesthésie locale continue (prolongeée) en obstétrique. In: Bull Soc Obstet Gynecol Paris. 20, 1931, pp. 35-39.
  6. RA Hingson, WB Edwards: Continuous caudal anesthesia during labor and delivery. In: Curr Res Anesth Analg. 21, 1942, pp. 301-311.
  7. a b c M. A. Frölich, D. Caton: Pioneers in epidural needle design. In: Anesth Analg. 93 (1), Jul 2001, pp. 215-220. PMID 11429369
  8. J. Eldor: Huber needle and Tuohy catheter. In: Reg Anesth. 20 (3), May-Jun 1995, pp. 252-253. PMID 7547666
  9. MM Curbelo: Continuous peridural segmental anesthesia by means of a ureteral catheter. In: Curr Res Anesth Analg. 28, 1949, pp. 12-23.