Calcification of the posterior longitudinal ligament in the cervical spine results in an occupying lesion in the spinal canal, making the spinal cord vulnerable to compression and producing clinical signs of spinal cord compression. The disease is most often seen in the East and rarely in Caucasians, with the highest incidence in the Japanese, followed by the Chinese. The incidence of the disease tends to increase with age, with the incidence in men being more than twice that in women. The entire cervical spine can develop, but cervical 5, cervical 4, cervical 6, and cervical 7 are the most common, and can develop in both the longitudinal and horizontal directions. Due to the calcium salt deposition and ossification of the posterior longitudinal ligament, the sagittal diameter of the cervical spinal canal is reduced, which can produce different degrees of direct compression and irritation to the spinal cord, and the ossified posterior longitudinal ligament can also compress the anterior spinal artery, resulting in inadequate blood supply to the middle sulcus artery and causing central damage to the spinal cord. At the same time, the ossification of the posterior longitudinal ligament (especially in the continuous type) can make the cervical segments in the ossified area stable and immobile, and the mobility of the affected segment can be completely lost, which inevitably aggravates the compensatory activity of the adjacent non-ossified cervical segments and accelerates their degenerative process, resulting in segmental instability of the adjacent cervical vertebrae, significant hyperplasia of the bony bulge, degeneration and herniation of the cervical disc, etc., which are often the direct causes of clinical symptoms or new symptoms. It is also the point of focus in the choice of treatment, especially surgical treatment. The etiology of ossification of the posterior longitudinal ligament in the cervical spine is still unclear and may be related to trauma, chronic strain, inflammation, cervical disc degeneration, and genetics. In addition to ossification of the posterior longitudinal ligament of the cervical spine, some patients also have ossification of the yellow ligament of the thoracic spine, the supraspinous ligament of the lumbar spine, or the patellar ligament, with the tendency of ossification in multiple parts of the body. Wu Hao, Department of Neurosurgery, Xuanwu Hospital, Capital Medical University
The danger of this disease!
The onset and progression of ossification of the posterior longitudinal ligament of the cervical spine are slow, and no clinical symptoms may appear in the early stage. When the ossified ligament thickens and widens to a certain degree and causes cervical spinal stenosis, or when the ossification of the posterior longitudinal ligament is not serious but there is existing developmental spinal stenosis, it can cause compression of the spinal cord or spinal blood vessels, so the symptoms appear mostly in middle age or older. Because the extent of ligamentous calcification does not affect the nerve root canal, the clinical symptoms are rarely neurogenic and mainly manifest as cervical spinal stenosis. The symptoms of spinal cord compression are characterized by chronic progressive spastic quadriplegia of varying degrees, often starting in the lower extremities, with symptoms in the upper extremities appearing after a month or so, or in the upper extremities or quadriplegia first. The upper extremities show soreness, numbness, swelling, dullness and weakness of both upper extremities, loss of hand dexterity, loss of grip strength, moderate or mild muscle atrophy, loss of pain perception, and positive Hoffman’s sign. The lower extremities may show numbness, weakness, spasm, difficulty in lifting, dragging or trembling, a feeling of stepping on cotton, a scissor gait if the adductor muscle is obviously spastic, in severe cases, unable to sit up and turn over on their own, increased muscle tone in the lower extremities, weakened muscle strength, positive fracture sensation, active or hyperactive physiological reflexes, positive pathological reflexes, there may be deep and superficial hyperalgesia. Sphincter dysfunction, difficulty urinating or urinary incontinence, low bowel function, abdominal distension, and a feeling of banding in the chest and abdomen are often present. Because of the slow onset of the disease, the onset of the disease is mostly unconscious, and the initial symptoms are not obvious, so it is often not taken seriously, but due to trauma or accidents can suddenly aggravate, and tetraplegia can occur. In our department, we have treated many patients who have been clearly diagnosed with this disease and refused surgical treatment, but due to sudden events such as accidental fall or sudden deceleration while riding in a car, resulting in quadriplegia, our department gave posterior single-opening surgery.
Treatment of posterior longitudinal ligament calcification of the cervical spine.
Treatment of ossification of the posterior longitudinal ligament includes conservative treatment and surgical operation. For those with slight symptoms and those who are older with organic disease, non-surgical treatment can be used. Commonly used are continuous cephalic traction, bed rest, cervical brace immobilization, physical therapy, and medication. Intermittent traction method and tui-na therapy for cervical spine have been reported to cause aggravation of symptoms and should be used with caution.
For patients with obvious symptoms and clear diagnosis from imaging data, surgical treatment should be considered.
Surgery for calcification of the posterior longitudinal ligament in the cervical spine is performed by both anterior and posterior routes, and severe patients sometimes require combined anterior and posterior surgery. The goal is to relieve the compression of the spinal cord by the ossified posterior longitudinal ligament, enlarge the spinal canal, and maintain spinal stability.
Anterior surgery: Theoretically, all posterior longitudinal ligament ossification should be performed by anterior cervical surgery to remove the ossified ligament directly and release the spinal cord compression, but for technical reasons, surgeons have to choose posterior cervical surgery for long segmental posterior longitudinal ligament ossification. The anterior cervical approach includes both resection and floatation of the ossified posterior longitudinal ligament. In the floating method, the intervertebral disc within the decompression area is removed first, and then the vertebral body is partially bitten off with a biting forceps, and the bone at the posterior edge of the vertebral body is removed by grinding with a micro-drill, so that the yellowish-white ossified mass of the posterior longitudinal ligament is gradually and significantly removed from the surgical field, and the ossified mass is completely free and softened on all sides to a floating state, and the ossified mass can gradually move forward due to the pulsating expansion of the subdural cerebrospinal fluid after decompression. The decompression area must be implanted with an iliac bone block. The anterior approach is technically demanding, and the operation is difficult and risky. No serious complications have occurred in the anterior surgery completed in our department so far.
There is no significant difference between laminectomy and vertebroplasty in terms of the degree of decompression, nerve recovery, spinal stability and cervical flexion deformity, while cervical vertebroplasty increases spinal stability, prevents the occurrence of cervical retroflexion deformity and controls the development of ossification foci in the posterior longitudinal ligament of the cervical spine. An important technical aspect of vertebroplasty is to maintain the posterior spinal structures stable at the time of surgery and to maintain the decompression effect on the spinal cord.