Nerves are part of the peripheral nervous system (PNS). They connect the central nervous system (CNS – the brain and spinal cord) with peripheral organs (eyes, skin, muscles, nose, heart muscle). The most important part of the nerve are the nerve fibers that conduct impulses from the CNS (motor fibers) or to the CNS (sensitive fibers). Most nerves are mixed nerves (motor and sensitive fibers). Their damage leads to weakness or paralysis of some muscles, as well as numbness of some parts of the body. Nerve injuries are present around the world in different countries (USA, Nigeria, Kenya, Tanzania, Germany, Japan, etc.).
Image: Section of nerves: the green dots represent nerve fibers. They are surrounded by a myelin sheath (orange). The fibers are grouped in bundles (fascicles) inside the nerve. Blood vessels pass between them that feed the nerve.Picture: On the right side of the body, complicated innervation of the skin by various nerves is shown. Knowledge of this anatomy makes it possible to diagnose problems.
Nerve surgery is a special neurosurgical discipline. It requires that neurosurgeons have specific knowledge of anatomy, surgical work with the nerve, and the use of intraoperative stimulation (examination of the nerve during surgery).
Nerve injuries
Nerve injuries can occur within open wounds (cuts, lacerations) or within closed injuries. An example of a closed injury is a fracture of the upper arm bone, parts of which (fragments) injure the radial nerve.
Figure: Fracture of the upper arm bone, fragments of which injure the radial nerve.
If a nerve loses its function after an injury, then muscle weakness and numbness of the skin in the region it innervates occur. However, this does not necessarily mean that surgery is needed. It is indicated only if there is a break in the nerve or its fibers. In the case of an open injury, this is immediately apparent. If it is a closed injury, it can be proved only by electroneuromyography (EMNG) recording, and only when at least three weeks have passed since the injury. This method uses electrodes to assess the functions of nerves and muscles.
In some nerve injuries, only dysfunction of nerve fibers occurs. In others, the fibers are broken, but not the entire nerve. In that case, the fibers can grow back from the place of injury to the peripheral organs (e.g., muscles or skin). In both cases, surgery is not necessary and therefore it is important to be able to recognize such injuries.
If the continuity of the nerve is damaged and/or the nerve cannot recover on its own, surgery is indicated. It involves releasing the nerve from the pressure of the surrounding scar (sometimes this is enough if the continuity of the compressed nerve is preserved). If the nerve is cut completely or partially, its continuity must be surgically established so that the nerve fibers can grow back into the part of the nerve below the injury. The continuity is established by a direct suture of the two ends of the nerve. If there is a nerve defect, sometimes nerve transplants from another part of the body (e.g., the sural nerve from the calf) must be used to connect them. The ideal time for surgery is within 3 months of the injury, but it makes sense to operate on the injured nerve even if more than a year has passed.
Figure: Connection of nerves with nerve transplants from another part of the body.
After the operation, the nerve recovers through the growth of fibers from the part of the nerve above to the part of the nerve below the injury. The growth rate is about 1.5mm per day. Therefore, full recovery takes several months after injury or surgery.
Pseudoneuroma
After an injury (traumatic or surgical) to smaller subcutaneous sensitive nerves, pseudoneuroma may develop on nerves or they may be compressed or tightened by surrounding scar tissue. It can become a cause of pain. Pain occurs during movement which irritates the injured nerve by moving surrounding tissues (muscles, skin, tendons) and the scar. It causes various forms of pain. Pain can also be present without movement. Pseudoneuroma or local irritation of the nerve with a scar can therefore mimic injuries or diseases of organs located below the injured or irritated nerve. For example this can be the reason for pain in the area below the right costal arch after removal of the gallbladder (cholecystectomy); pain after abdominal hernia surgery; pain after open fractures; pain after breast surgery; pain when breathing and moving after chest surgery; pain between the toes in deformities of the feet; etc. Multiple pseudoneuromas may be the cause of phantom pain after limb amputation.
The diagnosis of this painful syndrome after surgery is very technical. It requires a lot of thought because it often imitates the condition that the surgery was intended to correct or the injury of other organs. Because of this, patients often have repeated examinations of these organs.
Nerve blockades, which must be performed by a specialist who is well acquainted with this pathology, also help in the diagnosis of this condition.
Treatment consists of minor surgery to release the nerve and remove the pseudoneuroma. The procedure must deal with the end of the sensitive nerve that is left behind after the operation so that pseudoneuroma does not recur.
Nerve compression syndromes
During their journey from the spinal column to the muscles, skin and other organs, the nerves pass through various narrow channels. Sometimes over time these channels narrow too much, leading to pressure and nerve damage. The causes are different and depend on the localization. Each nerve can be pressed in several places. When that happens there is a pain in the area of the nerve that specifically irradiates, as well as numbness and tingling in a certain region and weakness of certain muscles. Problems usually occur in this order, but numbness may occur first, without pain or preceded by muscle weakness.
Treatment is initially conservative. In the beginning nonsurgical treatment can solve the problem. If the right combination of medications is prescribed, unnecessary surgery can be avoided. The combination and dosages of the drugs must be individual for every patient. It means that a detailed conversation with the patient, getting all the important details about the pain is very important. Interventional non-operative methods in the treatment of nerve pain are very powerful. If the pain is severe and lasts longer than a few months, and if there is significant nerve damage (shown by examination and EMNG), surgical treatment is required. It consists of releasing a nerve where it is pressed. Everything must be done so that the scar that forms later does not lead to re-compression on the nerve. Sometimes the nerve has to be moved to a new place so that the pressure does not reappear. On rare occasions, it is necessary to open the nerve and operate on it.
After the operation, the patient can start exercising the same day.
Part of the problem is resolved immediately by the operation. The pain is mostly reduced or even stopped in a few days. Also, after a few days, numbness and weakness are partially reduced. However part of the problem takes months to improve. It takes a long time for the nerve fibers, which were significantly damaged, to grow back. The more damaged fibers there are, the higher the percentage of problems that will take months to resolve, instead of immediately after surgery. Also, the more severe the nerve damage, the greater the chance that the nerve will not fully recover after the operation. However even then there is a significant improvement in over 90% of cases in terms of pain and over 50% of cases in terms of numbness and weakness. Nerves recover worse in the elderly, diabetics, alcoholics and those who have other reasons for polyneuropathy. Yet in the vast majority of cases, relatively easy surgeries resolve problems for patients after years of pain for which they have found no other effective treatment. Most of these surgeries can be performed under local anesthesia. If the pain recurs, in most cases it is not the result of ineffective surgery, but rather has another cause. In most cases this postoperative pain can be treated with medications. But it needs an individual approach for every patient. It is important to have a detailed conversation with the patient and get all the important details about the pain and symptoms.
There are various entrapments that can cause various symptoms, and it is often necessary to be examined by a doctor, experienced in the treatment of nerve diseases, in order to arrive at an accurate diagnosis. Nerve pressure can cause the following syndromes:
Neck pain
Pain with or without numbness and weakness of the shoulders
Pain with or without numbness and weakness of the upper arm (muscle)
Pain with or without numbness and weakness above the elbow
Pain with or without numbness and weakness in the elbow area
Pain with or without numbness and weakness of the forearm
Pain with or without numbness and weakness of the hand
Pain with or without numbness and weakness of the thigh
Pain with or without numbness and weakness of the knee
Pain with or without numbness and weakness of the lower leg
Pain with or without numbness and weakness of the feet
…
Each of these syndromes can be the result of pressure on different nerves.
There are several common entrapments:
Pressure on the ulnar nerve in the elbow (Cubital Tunnel Syndrome)
Predisposing factors are constant bending in the area of the elbow or leaning on the elbow. It is manifested by pain in the elbow that spreads more into the forearm. In addition to this, numbness occurs in the area of the ring finger and a pinky, as well as the inner part of the palm and forearm. Weakness and atrophy occur in the area of the muscles of the hand and forearm. If the disease goes away, the hand can begin to take the shape of a claw.
Treatment: In the beginning non-surgical treatment can solve the problem. If the right combination of medications is prescribed unnecessary surgery can be avoided. The combination and dosages of the drugs must be individual for every patient. It is important to have a detailed conversation with the patient and get all the important details about the pain and symptoms. If needed, the operation is performed with an incision in the area in the back of the elbow. It involves releasing the nerve and moving it to another place where it will not be exposed to stretching when bending the elbow. If the pain recurs, in most cases it is not the result of ineffective surgery, but rather has another origin. In most cases this postoperative pain can be treated with medications. But it requires an individual approach for every patient, involving a detailed conversation with the patient to get all the important details about their pain and symptoms.
Figure: Pressure on the ulnar nerve in the elbow – 1) The ulnar nerve, 2) The connective tissue that puts pressure on the nerve
Pressure on the ulnar nerve in the area of the root of the hand (Gyon’s Canal Syndrome)
Numbness in the area of the ring finger and pinky, clumsiness of the fingers, pain in the root of the hand.
Figure: Pressure on the ulnar nerve in the root of the hand
Meralgia paresthetica (pain in the thigh)
Unpleasant numbness in the anterior (outer) thigh. It is caused by pressure on the sensitive nerve for the outer part of the thigh at the place where it passes under the inguinal ligament (lateral femoral cutaneous nerve). It is increased by palpation at one point of the outer part of the groin. Painful numbness occurs, especially when walking. Conservative treatment means treating the pain, but also reducing body weight and strengthening the abdominal muscles. Unnecessary surgery can be avoided if the right combination of medications is prescribed. The combination and dosages of medication must be individual for every patient. It is important to have a detailed conversation with the patient and get all the important details about the pain and symptoms. Sometimes surgery is needed.
Figure: 1- The lateral femoral cutaneous nerve is most often pressed when it passes under the inguinal ligament and enters the thigh.
Pressure on the peroneal nerve below the knee (Peroneal Tunnel syndrome)
it often occurs in athletes due to hypertrophied muscles or after the fracture of a small bone of the lower leg (fibula neck). It can be provoked by a prolonged squatting position. The pain occurs below the knee and spreads more downward. There can be toe numbness. In the early or late stages of this disease, a “hanging” foot occurs and the patient is unable or experiences difficulty walking on his heels. Similar problems occur when there is a disc herniation between the 4th and 5th lumbar vertebrae which presses on the root of the L5 nerve.
Figure: Pressure on the peroneal nerve in the area below the knee- The knee joint is shown with 3 marking the peroneal nerve, and 2 marking the muscle that most often exerts pressure on the nerve
Conservative treatment means treating the pain and numbness. If an adequate combination of medications is prescribed unnecessary surgery can be avoided. The combination and dosages of medications must be calibrated individually for every patient. It is important to have a detailed conversation with the patient and get all the important details about the pain and symptoms. When a significant neurologic deficit occurs surgery is needed, sometimes urgently.
Tarsal Tunnel Syndrome
is a painful foot syndrome. It is caused by pressure on the posterior tibial nerve in the outer side of the ankle joint. At that point, the nerve passes under the ligament, along with tendons and blood vessels. If there is a pathological process under the ligament this can put pressure on the nerve. This can be caused by inflammatory processes of tendons and joints, long-term occupational loads, constant loads due to incorrect foot position, degenerative changes in the joints, scarring around nerves, injuries, rheumatic diseases, pregnancy, varicose veins, cysts, tumors, etc.
Figure: Tarsal Tunnel Syndrome
The disease is manifested mostly by pain and numbness in the area of the inner part of the foot, and in the big toe, second and third toes. The pain can spread upward towards the knee, even the hip. The pain usually occurs at night or after exercise (walking, standing). The patient may also feel that half of their foot is cold or dry.
A detailed examination is most important for making a diagnosis. If necessary, EMNG, X-ray or magnetic resonance imaging of the ankle are indicated. In diagnosis, it is most important to distinguish this disease from a number of other diseases that cause foot pain. Often these diseases are associated with this syndrome.
Treatment is first conservative – painkillers, reducing inflammation, foot distension, blockade, immobilization, etc. If, despite these measures, the pain does not stop, surgery is recommended. It involves removing all pressure on the nerve. The operation is routine and has excellent results in over 80% of cases. The results of the operation are mostly determined by an accurate diagnosis, because this disease can be replaced by other diseases, and can also be associated with them. In the first case, the operation will not produce any results, and in the second case, treatment of other causes is needed for complete elimination of the pain. If the pain recurs, in most cases it is not the result of ineffective surgery but has another origin. In most cases this postoperative pain can be treated with medications. But it requires an individual approach for each patient, and it is also important to have a detailed conversation with the patient and getting all the important details about the pain and symptoms.
Pressure on the occipital nerve (Neuralgia of the occipital nerve, Occipital neuralgia)
is a very common disease and is manifested by severe pain in the occipital region (usually on one side) in the form of occipital headache or neck pain. Pain may have the characteristics of electric shock, burning, etc. It can spread to the ear and the front of the neck or the front of the head. Numbness of half of the parietal part of the head may also occur. The disease often goes unrecognized or is misdiagnosed as a cervical syndrome. There are effective treatments. In order for treatment to be successful, it is important to determine for sure that the occipital nerves are damaged, which occipital nerve it is, and then determine the place (level) at which it is irritated and the type of irritation.
>> FULL TEXT on occipital headaches
Nerve tumors
Nerve tumors are very rare. The most common are neurofibromas and schwannomas. Treatment involves the surgical removal of the tumor. Most of these tumors grow next to or inside the nerve and can be removed.
Picture: Tumor in the area of the ulnar nerve (asterisk)
On rare occasions, these tumors grow permeating the nerve (plexiform neurofibroma). In these situations, complete removal of the tumor itself is not possible, and instead the whole nerve must be removed with the tumor, followed later by reconstruction. The main reason for this is the pain that cannot be treated in any other way.
Image: Magnetic resonance imaging of thick flesh and thighs. The arrow shows plexiform neurinoma.
Malignant variants of nerve tumors are rare. These are tumors over 3 cm in size, which grow rapidly and can cause ingrowth into the surrounding tissues
Hemifacial spasm
involves spontaneous involuntary spasms in the facial muscles. The disease usually begins with spasms of the muscles around the eye. The spasms are painless. There is a tendency to spread to other parts of the face. The most common cause is nerve irritation in the area inside the skull. It is important to correctly diagnose the problem and rule out other diseases that can lead to such ailments. Treatment involves the correct combination of medications preventing muscle cramps. Treatment in later phases may involve injecting Botox and/or surgically removing pressure on the facial nerve ( MVD – microvascular decompression ). Arteries, veins or adhesions near the facial nerve can cause the pressure.
Keywords: Neurosurgery Neurosurgeon Brain Prognosis Consultation Nerve Injury Carpal tunnel syndrome Entrapment Cubital Ulnar Median
