Ossification of the Posterior Longitudinal Ligament (OPLL) is a condition where the ligament running along the back of the spinal bones abnormally stiffens and turns into bone. This process causes the ligament to thicken, narrowing the space within the spinal canal. OPLL most often affects the neck, or cervical spine, leading to compression of the spinal cord and surrounding nerve roots. Managing OPLL requires understanding its progression and committing to long-term care.
The Basics of OPLL
The posterior longitudinal ligament (PLL) is a band of fibrous tissue that stabilizes the spinal column, extending from the base of the skull down to the tailbone. When ossification occurs, this soft tissue is replaced by bone, forming a mass within the spinal canal. While OPLL most frequently occurs in the cervical spine, it can also be found in the thoracic and lumbar regions.
The cause of OPLL is multifactorial, stemming from a combination of genetic and environmental influences. Factors such as diabetes, obesity, age, and mechanical stress on the spine are associated with its development. As the ligament hardens and expands, it presses on neural structures. This compression leads to myelopathy (spinal cord dysfunction) or radiculopathy (nerve root irritation).
Symptoms often begin subtly, presenting as mild pain, numbness, or tingling in the hands and arms. As compression increases, patients may experience clumsiness, difficulty with fine motor movements, and disturbances in gait or balance. In advanced myelopathy, symptoms can progress to include difficulty walking and issues with bowel or bladder control.
Daily Management Without Surgery
For patients who are asymptomatic or mildly symptomatic without severe spinal cord compression, conservative management is the first approach. This strategy focuses on alleviating symptoms, maintaining function, and monitoring the condition to prevent neurological injury. Physical therapy is a primary component, aiming to strengthen spinal support muscles and improve posture and flexibility.
Activity modification requires avoiding high-impact sports and movements that excessively extend or hyperextend the neck. Such activities can momentarily decrease the space available for the spinal cord, increasing the risk of injury. A physical therapist can help design a safe exercise regimen that prioritizes gentle, low-impact movements to maintain spinal health.
Pain management relies on pharmacological options, often beginning with non-steroidal anti-inflammatory drugs (NSAIDs) or muscle relaxants. For nerve-related pain, physicians may prescribe specific medications that act on the nervous system to calm irritated nerve fibers. A temporary cervical brace or collar may be prescribed to restrict movement and provide support during periods of increased pain, but long-term use is discouraged.
Ongoing monitoring is part of non-surgical management, involving regular neurological examinations to detect changes in strength, sensation, or reflexes. Periodic imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI) scans, tracks the rate of ossification and the degree of spinal cord compression. This surveillance helps the care team determine if the condition is progressing and if a change in treatment strategy is warranted. Patients without signs of myelopathy often remain stable without progression for extended periods.
When Surgical Intervention is Necessary
The decision to move from conservative management to surgery is based on indicators of disease progression or significant neurological deficit. Surgery is recommended for individuals experiencing progressive myelopathy, severe spinal cord compression, or symptoms that do not improve with non-operative treatments. The main goals of surgery are to decompress the neural elements (the spinal cord and nerve roots) and to stabilize the spine.
Surgical approaches are categorized as anterior (from the front of the neck) or posterior (from the back of the neck), depending on the extent of ossification and spinal alignment. For localized OPLL affecting only a few segments, an anterior approach, such as anterior cervical corpectomy and fusion (ACCF), may be used to directly remove the ossified mass. While effective, this direct decompression carries a higher risk of complications, including spinal fluid leaks, because the ossified ligament is often adhered to the dura mater (the protective covering of the spinal cord).
For OPLL spanning multiple vertebral levels, a posterior approach is often preferred as it is less invasive to the spinal cord itself. Procedures like laminoplasty involve hinging the back part of the vertebra (the lamina) to create more space for the spinal cord. Laminectomy, which involves completely removing the lamina, is another option and is often combined with spinal fusion for long-term stability. These posterior techniques indirectly relieve pressure and are favored when the natural forward curve of the cervical spine is preserved.
Following surgery, the immediate recovery phase involves a brief hospital stay and the initiation of early movement and physical therapy to prevent stiffness. Rehabilitation is important for long-term recovery, focusing on restoring strength, coordination, and range of motion. The initial recovery period can take several weeks to months, depending on the procedure’s complexity and the patient’s pre-operative neurological status.
Long-Term Outlook and Follow-Up Care
Living with OPLL, even after successful surgery, requires continuous vigilance, as the condition is chronic and can progress. The ossification process may continue over time, and there is a risk of recurrence or development at spinal levels adjacent to the original site. Progression of OPLL can occur years after a laminoplasty procedure.
Routine follow-up with a spine specialist or neurosurgeon is necessary for all patients, whether managed surgically or non-surgically. This ongoing care includes periodic neurological assessments and imaging, such as annual or biennial MRI or CT scans, to monitor for recurrence or progression. This proactive surveillance catches changes early, allowing for timely intervention before significant neurological damage occurs.
A long-term consideration is the heightened risk of acute spinal cord injury from minor trauma due to the narrowed spinal canal. Simple incidents like ground-level falls or whiplash can be devastating for individuals with OPLL. Therefore, avoiding activities with a high risk of head or neck trauma, such as contact sports or aggressive driving, is a necessary safety measure.
Long-term quality of life is supported by continued rehabilitation and, when necessary, access to pain management clinics or psychological support. While neurological improvement can be achieved through surgery, recovery is a lengthy process that involves adapting to residual symptoms. Long-term physical therapy helps maximize functional independence, ensuring patients maintain the strength and coordination gained during initial rehabilitation.