The Kuntz Nerve Controversey
Over the last few years many questions are being raised about the Kuntz Nerve. “What do you know about the Kuntz Nerve?” and “What do you do with the Kuntz Nerve?” are some common exampes.
It is difficult to explain the controversy surrounding the Kuntz nerve, which causes a lot of confusion among laymen and physicians alike. An understanding of the origin of the sympathetic enervation of the upper limb is important in surgical sympathectomy procedures such as ETS.
During the 1920’s, sympathectomies were performed for a variety of reasons such as elevated blood pressure, circulation problems within the hands, cardiac pain, etc. Most of the above-mentioned reasons were not cured by the surgery. When the sympathectomy was performed for circulation problems in the hands, there was an initial improvement with a warming of the hands and better blood flow but most of those failed after 6 months to a year.
This high failure rate prompted Doctor Kuntz to look for a reason behind the failure. Since one could not perform postmortem examinations on patients, he performed anatomical studies on cats. While doing this anatomical dissection on cats he found some nerve fibers connecting the sympathetic nerve to other nerves within the chest cavity.
Since then the name Kuntz nerve is used. These particular anatomical findings were not found in humans. The reason for the failures when sympathectomy procedures were done for vascular problems is not related to the procedure itself.
The reason for the failure is due to post denervation hypersensitivity (meaning extra sensitivity to circulating chemicals in the blood causing the blood vessels to constrict). Somehow this term Kuntz nerve found its way into modern sympathectomy literature.
Over the last few years there were two anatomical studies done on cadavers trying to solve this issue. In both studies, they found a nerve segment that goes in between the first intercostal nerve and the brachial plexus. The exact function of this nerve segment is unknown.
The intercostal nerves are made of bundles that consist of sensory, motoric, and sympathetic fibers running between the ribs. The brachial plexus is a motoric nerve bundle that innervates the upper extremities and the shoulders.
The exact function of that particular nerve is not known. Moreso the space between the first rib and the intercostal nerve is, generally speaking, an area not touched by ETS surgeons during the procedure. The fact that this area is generally not touched by ETS surgeons makes it less significant in regards to true nature of this elusive nerve.
The mere fact that an anatomical nerve was found does not mean that it has any physiological role in the sympathetic function. Surgeons who claim to see and cut the Kuntz nerve do not even do the dissection in those above-mentioned areas.
The eponym, nerve of Kuntz, should be restricted to descriptions of the intrathoracic branch of the first intercostal nerve. Surgeons who are performing the ETS procedure on a daily basis do not even get to that site. Bleeding problems, as well as severe collateral injuries, restrict the approach to those sites.
In order to expose this elusive nerve one must perform a very delicate dissection with two or three instruments to enable this step. Most of the ETS surgeons who perform this operation do it with one single instrument that does not allow this type of dissection.
Any Connections Between The Kuntz Nerve and Recurrence?
Recently Dr. Reisfeld went back to the anatomy laboratory and performed 6 cadaver studies. This means that 12 separate dissections were done in the upper part of the chest cavity trying to further clarify the issue of the “Kuntz nerve”. Those dissections were completed with the help of 2 experienced Anatomists (University Medical Doctors who teach anatomy in medical school).
No significant nerve connections were found between the second ganglia to the first ganglia. Between the first ganglia and the brachial plexus, some very fine fibers were found but there exact physiological function is not known. This particular area is not approached by any ETS surgeon because of the proximity to a variety of other important structures.
Doctor Reisfeld believes that current clinical and anatomical data do not support the Kuntz nerve as a significant reason for recurrence after a successful ETS procedure. The most likely reason for late recurrence is the creation of alternate pathways within the Spinal cord.
The possibility of a re-growth in the sympathetic chain is a practical possibility since the sympathetic chain has the ability to repair itself. The regrowth can happen if the operation is performed using the cutting method, excision, or ultrasound desiccation. Dr. Reisfeld found that with the clamping method the recurrence rate is even lower than the cutting method.
The above-outlined views about the Kuntz nerve were also supported in 2001. In the international meeting held in Finland, this view was supported by other leading ETS surgeons.
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