Cervical Surgery for OPLL (Ossification Posterior Longitudinal Ligament) and its Complications
Time: 03:00 pm – 05:00 pm
Sponsor: Connectionology Seminars of America, LLC
CLE HOURS EARNED: 2
We are honored to bring back leading Neurosurgeon – Dr. Nancy E. Epstein, M.D., F.A.C.S. on Wednesday, November 18, 2020 from 3:00 p.m. to 5:00 p.m. (EST) Eastern Standard Time.
Moderated by: Dustin B. Herman, Esq. with Spangenberg Shibley & Liber LLP – Cleveland, OH.
In this discussion, you will become familiar with the following:
• OPLL on MR studies. Hypertrophy or Ossification of the posterior longitudinal ligament appear as hypointense on MR. This is because ossification/bone on MR appears as a black/negative/hypointense image, and cannot clearly differentiate between disc (soft tissue) vs. bone (ossification of OPLL).
• OPLL on CT Studies: CT best demonstrates ossification/calcification. Initially, hypertrophy of the posterior longitudinal ligament (HPLL: Hypodense-low signal intensity), the precursor of ossification of the PL L(OPLL), consists of hypointense enlargement of the ligament with punctate ossification centers. This may initially appear to be “discs”. Classical OPLL becomes fully calcified/ossified and appears hyperdense on CT.
• OPLL is a major cause of anterior/front spinal cord compression. The PLL-posterior longitudinal ligament-is located behind the cervical vertebral bodies and in front (anterior) to the spinal cord. As OPLL progresses (HPLL/OPLL) it can result in increased spinal cord and nerve root compressive syndromes.
• OPLL Resulting in Radiculopathy: When OPLL compresses nerve roots this results in radiculopathy. Symptoms and signs are localized to single nerve root distributions. In the cervical spine the following are most frequently observed: C5-at the C45 level deltoid weakness and pin loss in a “silver dollar” distribution over the shoulder. C6-at the C56 level the C6 root exits. Deficits typically include the following weakness; biceps, extensor of the wrist, apposition thumb index/pinky, and sensory loss over the thumb and index fingers. C7-at the C67 level resulted in weakness of: apposition thumb/pinky, extensor phalanges, and triceps with sensory loss in the 3rd and inside aspect of the 4th finger.
• OPLL Resulting in Myelopathy: Myelopathy means cord compression. When there is cord compression due to OPLL this typically results in the onset of painless weakness. It may involve an entire upper or lower extremity, and can include diffuse sensory loss, hyperactive reflexes including Babinski response, and loss of balance, as well as sphincter dysfunction.
• Anterior Surgical Options for OPLL: Negative K Sign: This means that the amount of anterior spinal cord compression extends so far into the spinal canal that only an operation from the front of the spine will result in alleviating the problem. The K sign is determined by a line drawn from the middle of the spinal canal at C2 and C7; the anterior OPLL mass then has to extend behind/posterior to the longitudinal line drawn between these points. Anterior operations include: extended anterior discectomy/fusion (taking off part of the vertebral body above/below a disc space), but more likely anterior corpectomy/fusion (taking off an entire vertebral body from the front). The latter is more typically performed as the OPLL mass typically extends behind the entire vertebral body and is not located just at the disc space.
• Posterior /Anterior Surgical Options for OPLL: Positive K Sign. This means that there is less severe anterior disease that does not cross the line drawn from the middle of C2-C7. The surgical options here then include posterior as well as anterior cervical surgery.
• There are 4 types of Classical OPLL:
1. Segmental: located behind vertebral bodies.
2. Continuous: located behind vertebral bodies but crossing disc spaces.
3. Mixed: both the Segmental and Continuous forms.
4. Other: OPLL located at the disc spaces with some extension above/below the disc spaces.
On MR these lesions may appear as low signals (black) whether hypertrophied or calcified/ossified posterior longitudinal ligament. Recognizing these different forms is critical to operative planning.
• Three Signs of Dural Penetrance by OPLL: Single Layer Sign: a central OPLL component with significant cord compression, “C” Sign with Single Layer Sign; Single layer sign with C shaped configuration to either side indicated that dura may be turned on itself (e.g. imbricated), Double Layer Sign: This shows ossification of the posterior vertebral body, a low density sign that represents dura, followed by ossification (this is actually intradural). The double layer sign is most highly correlated with spinal fluid leaks, followed by the single layer “C” sign, and finally the single layer sign alone.