Lumbar Spinal Stenosis with Degenerative Deformity
The patient is a 79-year-old male with a 9-month history of back pain and left buttock and posterior thigh pain when walking more than one block.
Twelve years prior, he underwent an open L3-S1 decompressive laminectomy and non-instrumented posterolateral fusion L4-S1 for spinal stenosis, with good results.
His medical history includes paroxysmal atrial fibrillation. He has a pacemaker and takes an anticoagulant.
- Motor: full bilateral lower extremities, except left quadriceps 4+/5
- Reflexes: 1+ right knee, absent in the left knee and bilaterally in the ankles
- Negative straight leg raise bilaterally
- Forward flexed gait
- Hyperextension reproduces left leg pain
Epidural steroid injections and organized physical therapy did not benefit the patient.
Figure 1. AP CT scan shows prior L3-S1 laminectomy with solid posterolateral fusion, L4-S1
Figure 2. Lateral CT scan shows prior L3-S1 laminectomy with solid posterolateral fusion, L4-S1
Figure 3. Axial CT scan shows left sided L2-L3 lateral recess stenosis and foraminal stenosis
Figure 4. Axial CT scan shows left sided L3-L4 lateral recess stenosis and foraminal stenosis
Figure 5. Axial CT scan shows the prior fusion at L4-L5
Figure 6. Axial CT scan shows the prior fusion at L5-S1
Figure 7. 3D CT shows degenerative disc disease/collapse and coronal imbalance, L1-L4
Spinal stenosis at L2-L3 and L3-L4 with coronal imbalance
Suggest TreatmentIndicate how you would treat this patient by completing the following brief survey. Your response will be added to our survey results below.
L1-L4 MIS transpsoas interbody fusion with percutaneous pedicle screw fixation.
- Given the significant comorbidities and use of anticoagulation, the MIS technique minimizes blood loss
- Indirect decompression of the spinal canal and neural foramen with large interbody grafts avoids the risk of cerebrospinal fluid (CSF) leakage at the site of the prior laminectomy
- Improve correction of the patient’s coronal imbalance
Blood loss was less than 100cc during the total procedure.
The patient had immediate relief of leg pain and significant improvement in back pain. He was ambulating on post-operative day 1, and resumed anticoagulants on post-op day 3. His coronal imbalance is improved, and he continues to do well at his 6 month follow-up (Figure 12).
Figure 12. PA x-ray at 6 months post-op
This single case demonstrates the marked utility of the lateral approach for revision spine surgery, coronal deformity correction, indirect decompression, and MIS fixation. Most surgeons implementing the DLIF/XLIF procedure can attest to the difficulty with conventional approaches to this type of pathology.
A standard 360 approach carries numerous risks in a patient such as this. The heavily calcified vasculature makes an anterior release significantly more challenging. An ALIF at the index levels would be tremendously difficult even with a highly skilled access surgeon. Complications of a posterior approach include a significant risk of subsidence and/or suboptimal deformity correction. Furthermore, as mentioned, the posterior approach is highly susceptible to cerebrospinal fluid leakage.
The lateral approach offers significant advantages and has afforded general spine surgeons the ability to tackle more complex deformity cases. Several tips can aid this transition.
Patients with coronal deformity are typically approached from the concave side (convex down) to facilitate correction. This allows the bed to be flexed and act as a fulcrum over which the patient's spine can be "broken." Other times, a bolster between the patient and the operating table can facilitate additional lateral flexion. Many times three or four levels can be treated from a single incision because the angulation of the disc space allows radial realignment.
It is essential to provide aggressive ipsilateral and contralateral release to ensure adequate reduction and graft stability. I typically use a large Cobb elevator to release the annulus on both sides; however, many surgeons use the smallest dilator, which is blunter and presumably safer.
Docking and Anchoring
I typically seal the bottom of the small dilator tube with a piece of bone wax. Then I can hover the small dilator with K-wire preloaded over the disc space and easily deploy the K-wire into the tight disc space. Then I swap out the PEEK dilator for a metal one, which I can hammer into the disc space. This gives a very rigid docking point upon which to anchor larger dilators and ultimately, the self-retaining retractor.
Order of Treatment
Most lateral access surgeons practice a top-down model of coronal deformity correction. They start at the top level of the deformity first and push the cephalic body away with progressive dilation at each level. More extreme curves may require a top-bottom-middle correction where the outermost and most difficult levels are done first.
Conversely, bottom-up progression is favored for sagittal deformity correction. In these cases restoration of lordosis is facilitated by starting at the bottom. This pushes the more cranial level posteriorly into the field. Certain cases may require the release of the anterior longitudinal ligament, although this should be reserved for surgeons well versed in the lateral approach.
Additional release and correction is obtained by sequentially larger dilators. Typically, the disc space is the focus of the deformity and adequate distraction with parallel or lordotic spacers will realign the spine. However, in some cases, severe bone remodeling may result in trapezoid-shaped vertebrae. Many vendors now offer coronally-tapered implants to optimize realignment.
Conclusion The surgeons are to be commended on their deformity correction, low blood loss, and excellent outcome.