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Patients with cervical disc herniation will present with upper extremity radicular pain rising in the neck and extending down the arm into varying distributions, depending upon which nerve root is involved. At the time the major component of pain may be only into the shoulder and upper arm with paresthesia and numbness extending into the fingers. If significant nerve root compression and inflammation exists, then motor weakness is present in the muscle groups served by that nerve root. Presentation is often acute and patients will describe the onset of arm pain after a traumatic event but at times note discomfort without any precipitating event. These patients often complain of a prior history of intermittent arthritic type neck discomfort.
Initial evaluation requires a detailed neurologic examination to document the extent of any specific sensory or motor deficit in the involved extremity. Additionally, it is imperative to determine whether there is any evidence of spinal cord compression by carefully examining the opposite arm as well as the lower extremities including position sense, tendon reflexes and plantar responses to evaluate all components of spinal cord function. There may be difficulty with bowel or bladder control as this is at times an early symptom of spinal cord dysfunction. Radiculopathy refers to a dysfunction of a nerve root usually due to mechanical compression. In this context it is usually due to a herniated disc or bone spur. Myelopathy refers to compression of the spinal cord. In most cases, however, simple cervical disc herniation occurs laterally in the region of the neural foramen and there is usually not clinical spinal cord involvement. Patients are initially managed with limitation of activities and appropriate pain medication. A brief course of corticosteroids may also be helpful. Radiologic evaluation includes plain films of the cervical spine, at times with flexion and extension views and also at times oblique views to delineate the neural foramina. Plain films are essential for clearly documenting any bony foraminal encroachment, as well as the degree of disc height loss and spondylosis. MRI scan will demonstrate the disc herniation and the degree of root and/or cord compression.
An anterior approach to the cervical spine is utilized for removal of herniated discs that are compressing cervical nerve roots or at times the spinal cord and also for decompression of these structures by removal of spondylitic bone ridges or spurs that may arise from the vertebral body endplates adjacent to the disc and encroach into the spinal canal or neural foramina. At surgery, a transverse anterior incision is made to the right side of the front of the neck over the involved level. At times, in procedures that will span multiple vertebral levels, an oblique incision along the medial border of the sterno mastoid muscle is undertaken. The anterior cervical spine is approached by dissecting medially to the carotid sheath and its structures and laterally of the "strap" or paratracheal musculature. Retractors are placed under the longus colli muscles which lie directly in front of the cervical spine. Involved disc levels are then resected and high speed drills used to remove bony endplates and spurs. The procedure is completed when the anterior aspect of the dural sac and nerve root exit zones are fully visualized and decompressed.
Bone grafts are placed into the spaces where disc was removed. In the past, grafts had been obtained from the patient's iliac crest and at times still are, although this usually produces much more discomfort than the actual surgical site. Cadaveric allograft is now used almost exclusively. Due to extensive precautions in selecting the donors, harvesting the bone graft and its stabilization prior to implantation the risk of infection from such banked tissue is negligible. At times, an entire one or more vertebral bodies are resected using the same method in cases of tumor or multiple levels of severe degenerative disease. Though the majority of patients heal quite well from the standard approach, some are at higher risk for nonfusion of the bone graft. Patients who have difficulty limiting their activities after surgery and heavy smokers are at increased risk for nonfusion, and therefore a thin metal plate is applied to the anterior portions of the involved cervical vertebrae with special locking screws. This adds little time to the surgical procedure and generally does not increase the morbidity. Locking plates are also used when multiple vertebral levels are operated upon.
In the standard case of anterior cervical discectomy with fusion, a hard cervical collar is applied at the end of the procedure and the patient wears this throughout the hospital course and at home for the next several weeks, though it may be removed for brief periods for bathing, etc. The need for cervical collar is eliminated by using the metal plate, but thus far this has not been considered an adequate reason by itself to use the plates in routine cases. In most cases, patients are mobilized as soon as they are able and can be out of bed as tolerated while wearing the hard cervical collar. In many cases, patients describe immediate, almost complete, relief of their arm pain and are quite gratified by the surgical results even in the first few postoperative days. As after lumbar disc surgery, paresthesia may continue for some time. It is routine to obtain plain films of the cervical spine the first postoperative day and x-rays are performed in the operating room at the end of the procedure. Patients can usually be weaned rapidly from intravenous analgesics and usually tolerate liquids by mouth the morning after surgery. They may complain of a "scratchy" throat as a result of the endotracheal tube and the necessary retraction during the procedure. This usually subsides over a few days. Sometimes topical anesthetic sprays such as "Chloraseptic" provide relief. Perioperative antibiotics and corticosteroids are continued for 24 to 48 hours postoperatively, and at times patients are discharged with a tapering dose of steroid. The typical complaint of pain in the interscapular region is a referred syndrome due to distraction of the upper vertebral bodies used during graft placement. This is quite common, is not indicative of any difficulty and will subside over several days to two weeks. Patients are often ready for discharge within 24 to 48 hours after the procedure. There are often many questions and anxieties regarding the cervical collar and fears that the neck is "unstable" from the surgery. It should be noted that the hard collar only serves to moderately limit the normal motion of the neck and is a psychological device to remind the patient to avoid over exertion. However, the cervical spine is not unstable in any way and patients' fears could be allayed in this regard. It is common to have the patient wear the hard collar even while sleeping for the first two to three weeks after surgery and if directed by the surgeon, it may then be taken off at night. Patients are instructed, as with lumbar surgery patients, to avoid bending or exertion as well as driving a motor vehicle until further instructions are given on the post operative visits. Anterior cervical incisions are usually closed with a subcuticular suture ("below the skin") and covered with steri strips (paper strips) and as such should be kept dry for the first six to ten days following surgery. At that point, the edges of the steri strips will loosen and may be removed either by the patient or in the doctor's office.
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