Massage, double crash syndrome and axoplasmic current
Nerve compression is a common cause of pain and discomfort. In some cases, compression of several sections of the same nerve is observed at once, which can be located at different levels of its length – double or multiple compression syndrome, which is also called double crash syndrome or multilevel neuropathy.
For example, with a double crash syndrome, a person may manifest symptoms characteristic of both the upper chest aperture syndrome and carpal tunnel syndrome. Double crash can also affect the lower limbs. So, for example, compression of the sciatic nerve by the piriformis muscle may be accompanied by compression of the same nerve in the region of the posterior thigh and in the tarsal (tarsal) canal of the ankle.
In this case, it is very important to be able to recognize the presence of multilevel nerve damage, because this injury requires a special approach to work.
Physiology of nerves
To better understand the essence of the double crash syndrome, let’s first turn our attention to the physiology of nerves. The nerve region closest to the spinal cord is called the nerve root (Fig. 1). The spinal nerve roots are arranged in pairs – the dorsal root carries sensitive, afferent fibers going to the spinal cord, and the ventral root carries motor, efferent fibers coming from the spinal cord and providing innervation of the peripheral muscles. Sensitive and motor fibers then combine to form nerve trunks. Nerve trunks, in turn, converge together on the way from the spinal cord to the limbs.
Intertwined with each other, these nerve trunks form a group of nerves – the nerve plexus. A great example of this is the brachial plexus in the neck. Very often, the plexus has many connections with various nerve trunks. The nerve trunks, leaving the plexus, are divided into separate nerves, which then innervate various parts of the limbs. These individual nerves are called peripheral. Such nerves include the median nerve, radial nerve and ulnar nerve.
Doctors distinguish several varieties of this type of nerve damage, depending on the place of compression.
Compression of the spinal roots is called radiculopathy or radicular syndrome. Compression of other sections of the peripheral nerve is called neuropathy. Squeezing of the nerve trunk at a site located within the borders of the plexus is slightly less common – such damage is usually called plexitis.
Nerves extending from the spinal cord are surrounded by several layers of connective tissue, including the endoneurium covering each nerve fiber. Nerve fibers are combined into bundles, covered with another layer of connective tissue – perineurium. Then, numerous bundles of nerve fibers are combined into a peripheral nerve, covered with the last layer of connective tissue – epineuria (Fig. 3). These layers of connective tissue surrounding the nerve fibers play a crucial role in the development of compression pathologies of the nerves, such as double crash syndrome.
In addition to several layers of connective tissue and the nerve fibers themselves, each peripheral nerve has a complex blood supply system. It consists of many tiny blood vessels located in the tissues of the nerve, which are responsible for the flow of fresh blood necessary for the normal functioning of the nerve.
Ischemia (a violation of blood supply) due to compression often causes various neurological symptoms and also plays a role in the development of double crash syndrome. The layers of connective tissue also act as tubes through which various cellular fluids are supplied. Nerves have their own system for delivering the nutrients necessary for proper functioning. Nerves receive nutrients due to the slowly flowing axon from the body of the neuron to the periphery of the cytoplasm – axoplasm. The movement of axoplasm in nerve tissue is called axoplasmic current. In case of violation of this current, which is often observed with compression of the nerve, a person may have neurological symptoms, for example, pain, paresthesia, numbness or impaired motor function.
Why is this happening?
Double crash syndrome can develop due to the fact that a violation of the axoplasmic current in one part of the nerve can disrupt
functioning of tissues in areas remote from the lesion site innervated by the same nerve. For example, if a person has proximal compression of the brachial plexus, all parts of the nerve located distal to the damage site are more susceptible to the development of this pathology due to a violation of the axoplasmic current and, as a result, a decrease in the supply of nutrients to the distal nerve tissues. This may be the reason why many people often simultaneously suffer from symptoms of upper chest aperture syndrome and carpal tunnel syndrome.
Despite the fact that this disease is usually called double crash syndrome, the nerve can be affected immediately in three, and sometimes four, areas.