Case 5 Lumbar disc prolapse

Figure 5.1: MRI axial T2 of the patient.

Clinical presentation

• Male patient 63 years old.
• The condition started 4 years ago after several instances of lifting heavy weights.
• The patient developed gradual progressive low back pain, which worsened 2 months ago, associated with bilateral sciatica of L5-S1.
• The symptoms include bilateral calf muscle claudication.
• Despite this, the patient retains full power, has intact sensations and sphincters, positive right SLR at 60 degrees, and positive bilateral Patrick’s test.

• Q1: What are the different zones of lumbar disc prolapse? Is there any influence of the zone prolapsed on the radiculopathy developed?
• It may be central, subarticular, foraminal, extraforaminal and anterior. A point of differentiation is that foraminal and extraforaminal prolapses will compress the nerve root at the same level as the vertebra above, unlike central and subarticular prolapses, which will compress the traversing root below.

Figure 5.2: Different zones of lumbar disc prolapse.

• Q2: What is the content of the keyhole configuration in this MRI? And what is the cause of the hyperintensity around these structures?
• The contents of the intervertebral foramen include the nerve root sleeve and segmental intervertebral vessels. The cause of hyperintensity on MRI is due to the fat content.

• Q3: How can you differentiate clinically between sciatica due to lumbar disc prolapse and claudication pain caused by lateral recess stenosis?
• This can be differentiated clinically by the following:

1. Pain from lateral recess stenosis increases with standing and walking, similar to claudication pain caused by lumbar canal stenosis, and improves by leaning forward, squatting, or sitting.
2. The Valsalva maneuver can increase pain in cases of lumbar disc prolapse, but not in lateral recess stenosis.
3. The Straight Leg Raise (SLR) test may be positive in lumbar disc prolapse, and pain increases with sitting, unlike lateral recess stenosis, which worsens with prolonged sitting.

• Q4: At what degree is the Straight Leg Raise (SLR) considered positive and significant? If a patient has significant SLR limitation on one side, can this patient sit?
• The Straight Leg Raise (SLR) is considered positive if pain develops at 60-70 degrees. Patients with a positive SLR can sit because the SLR test requires unilateral flexion of the hip and extension of the knee to provoke pain, whereas sitting involves bilateral flexion of both the hips and knees.
• Q5: What are the boundaries of the lateral recess? Providing an image would be helpful.
• The boundaries of the lateral recess are:

1. Anterior: The anterior boundary is formed by the posterior edge of the vertebral body and the intervertebral disc.
2. Laterally: The lateral boundary is created by the pedicle of the vertebral arch.
3. Posterior: The posterior boundary is the superior articular process.
4. Medial : The medial boundary is the thecal sac.

Figure 5.3: boundaries of the lateral recess.