Cervical disc herniation

Zeljko Kojadinovic, MD- Neurosurgeon and Pain Specialist

Cervical disc herniation

Zeljko Kojadinovic, MD- Neurosurgeon and Pain Specialist

There are three types of processes on the cervical spine that can be treated surgically. These are: a) pathological changes that put pressure on nerve structures (nerve roots and/or spinal cord); b) instability of parts of the spine, and c) another, surgically resolved, cause of pain.

The most common pathological changes that put pressure on nerve structures and spinal cord occur as a consequence of degenerative changes within parts of the spinal column (discs herniation, spurs of vertebrae and joints, ligaments hypertrophy). Tumors, infections, congenital anomalies, or injuries are less common. These compressive changes most often, in addition to pain, also cause some neurological damage.

Degenerative changes can affect the discs. Over the years “material fatigue” occurs as a consequence of the load and/or poorer composition of the disk (a disk less resistant to repeated loads can be hereditary). The disc consists of a central part (nucleus pulposus) that serves as a shock absorber, is richer in water and has a peripheral ring that strengthens the disc. In the case of degeneration, the central part loses water, starts to become fragmented, and the peripheral ring breaks. Because of that, the central fragment can protrude backward through the fractured ring and compress nerve structures-nerve roots and/or spinal cord. (as is the case in the picture below). This process can be diagnosed as disc herniation, disc protrusion, disc extrusion, etc. In clinical terms this may correspond to diagnoses of radiculopathy (lesion of a nerve root) and/or myelopathy (lesion of the spinal cord). The discs are named after the vertebrae between which they are located: C2-C3, C3-C4, C5-C6, C7-Th1. Disc diseases are very frequent around the world in different countries (USA, Nigeria, Kenya, Tanzania, Germany, Japan, etc.)

Figure: A cross section of the cervical vertebra and the disc between the 6th and 7th vertebrae. The disc has degenerated and its central part has partially “leaked” backward through the crack of the peripheral ring. That part of the disc puts pressure on the nerve roots and the spinal cord (yellow in color). This can lead to radiculopathy and myelopathy with disturbances in the sense of touch, as well as a decrease in muscle strength in all four extremities. The pain spreads to the neck, the shoulder, and along the arm with numbness of the fingers and weakness of the muscles of the hand. The function of ulnar nerve, which arises partly from the pinched nerve root in the picture, is most affected. Then the pinky and ring finger would tingle and experience weakness.

Figure: After exiting the spinal column, the “pinched” root forms an ulnar nerve, and pain and numbness spread along it to the little fingers. Due to this, the problem in the spine can be manifested in, for example, numbness of the little finger.

This picture shows a profile section of the cervical spine and a disc herniation on two levels that put pressure on the spinal cord. The disc is in front, and the spinal cord is behind it.

Image: MRI of cervical spine shows disc herniation compressing the spinal cord.

Vertebral degeneration leads to a bony narrowing of the canal called spinal canal stenosis. Stenosis can be of the central part of the spinal canal or of the lateral parts (lateral recess). The narrowing is most often caused by various bone growths (osteophytes) from parts of the vertebrae (Terms related to this are spondylosis, spondylarthrosis, osteophytes). These osteophytes can also put pressure to nerve roots and the spinal cord.

Stenosis due to bone spurs is more common in the cervical spine, and disc herniation in the lumbar spine. The thoracic spine is less frequently affected by these processes.

Symptoms

Diseases of the cervical spine are numerous and mostly begin with various pain syndromes. Neck pain with or without irradiation to the shoulder and arm is most common. In advanced disease, and sometimes from the very beginning, there may be signs of damage to the roots (radix) of the arm nerves (radiculopathy). Radiculopathies are manifested mostly by pain, numbness and weakness of the arms. If numbness occurs, it is most often localized on the hand and fingers. The patient may also have difficulty walking because of compression to the spinal cord (myelopathy).

Diagnosis

If any of these symptoms occur, the patient will be referred to a specialist (neurosurgeon, neurologist or physiatrist) who will examine him neurologically and then determine what additional tests may be needed. The most common additional examinations are X-ray of the spine in various projections; electromyography (EMG, EMNG), which tests the condition of nerves and muscles; somatosensory evoked potentials (SSEP), which tests the condition of the spinal cord and nerves; or imaging of the cervical spine by computed tomography (CT of the spine), or more often by magnetic resonance imaging (MRI). Other diagnostic methods may also be considered.

The number of conditions that can be diagnosed is large. The process which leads to a different level of diagnosis in the same patient can be next: degeneration and stress of the disc lead to “leakage” of the disc (disc protrusion), which presses on the nerve root and spinal cord and damages it (radiculopathy, myelopathy), and this is manifested as neck and arm pain (brachialgia). So, this patient will receive a diagnosis of neck and arm pain from a doctor, a diagnosis of radiculopathy and myelopathy from a neurologist, and after a magnetic resonance imaging of the spine, a diagnosis of disc herniation or spinal stenosis will be arrived at. Only all three of these diagnoses combined reflect the true condition of the patient. This clinical picture is specific to disc herniation.

Painful syndromes in the cervical spine spine can be different from disc protrusion.

Neurological deficits can take the form of damage to the nerve roots for the arms due to pressure on them (radiculopathy) or damage to the cervical part of the spinal cord (myelopathy). Cervical radiculopathy is most often manifested by pain that spreads to the shoulder and arm; numbness and tingling most often in the fingers of the hand; weakness of one or more muscle groups in one or both arms, followed by muscle atrophy. Myelopathy is most often manifested by weakness, clumsiness and numbness of legs.

If you have been given a neurosurgical diagnosis and suggested operative or non-operative treatment, you can consult us if you have any doubts. This will make it easier for you to accept the proposed treatment from your doctor and, since you have no doubts, the treatment will have a better result or you will opt for a different type of treatment. We will explain whether we think surgery is indicated, which operative methods exist, where in your country such surgeries are performed, what their risks are and how to reduce them. We will also answer all your questions.

Treatment can be symptomatic, physical, or surgical. The goal of treatment is to “move away” the part that puts pressure on the nerve structure. The main question, if the patient has been diagnosed with disc herniation, is whether or not to perform surgery. If the patient only has pain due to disc herniation, he should try all possible methods of pain therapy before resorting to surgery. If the pain is treated properly, most disc herniations do not require surgical treatment. If there is motor deficit (weakness of arm or leg muscles) indication for surgery is stronger.

If indicated, the operation of disc herniation is performed by accessing the disk “from the front” or “from the back.”

In the cervical spine, if the spurs of bone (osteophytes) dominate, the removal of the complete disc with osteophytes and disc replacement is usually performed by surgery from the front. Instead of the removed disc, a pelvic bone graft, artificial materials (cage), or a prosthesis are inserted.

Picture: An incision on the front part of the neck (length about 4 cm) approaches the front part of the spine. The disc is removed. The disk replacement is performed, and the wound is sutured so that, after a few months, the incision is no longer noticeable.

Insertion of a bone graft (pelvic bone graft) instead of removing a disc. After this, stabilization can be accomplished with a plate and screws that are screwed into the vertebral bodies.

Figure: X-ray of the cervical spine after disc surgery – Removed discs replaced with disc prostheses.

If there is only a disc herniation putting pressure only to nerve root in the area of the neck , a back operation can be performed, similar to that in the lumbar spine (fenestration). If vertebral spurs exist on many levels (more than two), posterior surgical decompression is performed by removing posterior parts of the vertebrae- lamina (laminectomy, laminotomy). There are also other reasons for choosing the posterior over front surgical approach.

Figure: Removal of the lamina (posterior part of the vertebra) from the vertebrae C4, C5 and C6 (laminectomy)

Spinal instability involves any change in the relationship between the vertebrae that leads to posture disorders, pain and/or neurological damage. It is most often the result of injury or degenerative changes. That instability is diagnosed by X-rays, CT and MR images. After that, we decide whether to treat the instability surgically or through conservative methods.

Figure: Instability of the cervical spine after vertebral fracture C5

Figure: This drawing shows the stabilization of the cervical spine from the front. The screws are placed in the vertebral bodies and connected by a plate.

Figure: An X-ray shows the stabilization of the cervical spine from the front. The screws are placed in the vertebral bodies and connected with a plate.

Figure: The X-ray shows the stabilization of the cervical spine from the front and from the back.

Prognosis

In cases where surgery is the best option, the pain is successfully resolved surgically (disappears or is significantly reduced) in 90% of cases. If the operation is performed on time, the damage to the nerves and spinal cord (weakness, numbness, clumsiness) can be significantly reduced.

Surgical treatment leads to the removal of pressure on nerve structures and sometimes to stabilization of the spine. This reduces pain and prevents further deterioration of nerve elements.

Damaged nerves and, to a lesser extent, the spinal cord, recover after removing the pressure on them. Recovery from residual neurological deficits (muscle weakness, numbness, clumsiness, tingling, etc.) requires time and additional therapeutic methods. Usually, 75% of recovery occurs in the first 6 months. If the neurological damage was greater and lasted longer, especially in the elderly, a more permanent deficit may remain.

Surgical treatment of the spine is only part of the therapy. Before, and especially after the operation, other methods of treatment are needed. Most important is symptomatic and supportive therapy, as well as physical treatment and changing the patient’s habits. Support for nerve tissue regeneration involves the use of various medications. These drugs are often expensive and their therapeutic effect is not crucial, and often not even proven (various B vitamin preparations, OHB-12, etc.).

There are numerous methods of physical treatment, and we emphasize the importance of kinesitherapy, while educating patients about risk factors. There is also electrotherapy, magnetotherapy, laser, heating, massage and more alternative methods – acupressure, chiropractic, acupuncture. These alternative methods of treatment are more common in some countries than in others. It is important to know that the therapist must be educated and professional, and that these alternative methods should not be encouraged when there are more successful methods of treatment available. It is often not clear to patients that these methods can also have contraindications and harmful effects.

However, neck pain can remain after surgery due to the damage already inflicted to the nervous structure, but also due to the existence of associated diseases. They involve pain that is not caused by operated pressure on the nerve root or instability. This pain is described in the introductory section. These include, for example, myofascial pain, chronic pain from previous long-lasting nerve root damage, and other types of pain. In addition to this, risk factors remain after the operation: excess weight, weakness of the muscles that stabilize the spine, improper movements and lifting of loads, improper posture, etc. These and other changes cause reduced mobility in various joints. In all these cases pain therapy is necessary after the operation.

After determining the real cause of the postoperative pain, an individual combination and dosages of medication can be prescribed. This combination of medication is always individual and should be adjusted in regular contact with the patient over the first 6 weeks. At the beginning of this period the pain should be significantly reduced or completely solved. It should remain so to the end of the 6 weeks in order to achieve long-lasting results. To provide this during this period, the doctor must be available to the patient at any time so that he can easily contact him if the pain increases.