Cervical disc hernia, when should it be operated?
Cervical disc herniation is a very frequent pathology in our practice.
An important factor in the cervical spine is that it lodges the cervical spinal cord in its canal (Figure 1). From it originate the nerve roots that are directed to the upper extremities (arrows). Its function of support and mobilization of the head gradually overloads the seven cervical vertebrae, degenerating them. When the disc is affected, it bulges into the canal, the famous cervical disc hernia (Figure 2).
The degeneration of the intervertebral discs causes a decrease in height and involvement of the vertebrae cushioning. In more advanced stages deteriorated discs undergo inflammatory changes that are related to cervical pain. Likewise, there is bone growth towards the canal and the conjunction holes (foramina), with narrowing (stenosis) of the same.
The main symptomatology of cervical spine alterations is pain, which neurosurgeons call cervicalgia. Cervicalgia can be very annoying and be invalidating for the patient who suffers it. Another characteristic symptom of cervical disc herniation is pain radiating from one or both arms, the cervicobrachialgia.
The stenosis of the canal and the foramina determines a compromise of the spinal cord and nerve roots. This is also related to the appearance of neurological symptoms, characterized by pain irradiated by a certain area of the upper extremities (cervicobrachialgia), sensory disturbances in the form of tingling (paresthesias), and loss of strength.
Fig. 2 Magnetic resonance of a patient with a herniated disc C5-C6.
In acute cervical disk herniation, the herniated disc can compress the spinal cord in a significant way, with the possibility of spinal cord damage (myelopathy), which can cause a loss of strength in the patient’s extremities.
If the disc fragment moves laterally towards the foramina (Figure 3), the involvement of the nerve root causes a very disabling pain distributed by the arm, the cervicobrachialgia.
The fundamental imaging test for the correct assessment of cervical hernia is magnetic resonance imaging. With it we can appreciate the involvement of nerve structures (spinal cord, nerve roots), as well as the intervertebral discs.
The evaluation of the state of the nerves and the medulla is carried out by electromyography (EMG) and evoked potentials (SSEP), respectively.
Evolution and treatment
The majority of patients suffering from this cervicobrachialgia, the ¨cica¨ of the cervical spine, will improve with standard medical treatment, analgesics and anti-inflammatories, modulating drugs such as gabapentin, pregabalin, muscle relaxants and occasionally corticosteroids such as dexamethasone.
In those cases with moderate-large disc herniation, the clinical course is usually unfavorable, with recurrence of painful episodes, which requires the use of medical treatment at high doses. This fact will favor the appearance of side effects and a decrease in the quality of life of the patient.
Patients with this type of symptomatology should be referred to the neurosurgeon if the clinic does not progress favorably or if neurological symptoms are associated with alertness such as loss of strength. When medical treatment fails or in case of neurological symptoms of concern, treatment will be opted for neurosurgical, cervical microdiscectomy. By means of this technique, the affected disc or discs are accessed from a small wound in the anterolateral part of the neck. Once the disc and the bone peaks that protrude towards the canal are removed, we proceed to the opening of the common ligament, after which we can see through the surgical microscope the already decompressed spinal cord.
Subsequently, a cervical disc prosthesis (M6c Spinal Kinetics) is placed (Fig. 4), which maintains the normal mobility of the cervical spine.
Another option is fusion or arthrodesis. A biocompatible box filled with bone substitute is placed, held with a small plate with screws.
The intervention is very well tolerated by patients, with hospital discharge in about 24 hours.
The period of complete recovery after neurosurgical intervention of a cervical herniated disc is approximately 4-6 weeks, after which the patient can resume their usual activities.