Iatrogenic Facet Instability
The patient is a 45-year-old, Caucasian female, who presented with a chief complaint of low back pain. The patient’s history is notable for laminectomies at L3-L4 and L4-L5, performed for stenosis 2 years prior to presentation in our clinic. The outcome of this surgery was resolution of leg pain, but the patient complained of mechanical low back pain. The patient was told by her first surgeon that nothing was wrong and was then referred to a pain management doctor. The new doctor adjusted pain medications and eventually performed a spinal cord stimulator trial. This was successful in decreasing the low back pain (LBP) by 50%.
The patient presented in my clinic for possible implantation of a permanent spinal cord stimulator. At the time of presentation, she was taking Oxycontin, Cymbalta, and break through Percocets. She was on no other medications, and reported no other significant medical problems. The patient reported her back pain as being 7 out of 10. Physical activity intensified her low back pain, while moderate improvement was reported with rest.
The patient was thin, with a BMI of 22. Diffuse tenderness was noted in the mid-lumbar area. Coronal and sagittal plane alignment was normal. Lower extremity motor strength was normal. Sensory and reflex examinations were also normal. Range of motion was limited in the lumbar spine by pain. All major motion aggravated the pain.
Previously, the patient had undergone laminectomies at L3-L4 and L4-L5. She had failed physical therapy and chronic pain management.
Figure 1A: AP lumbar x-ray
Figure 1B: Lateral lumbar X-ray
Right Axial Left
Figure 2: CT scans showing axial and sagittal views of L3-L4
The patient was diagnosed with iatrogenic facet disruption at L3-L4, disc degeneration at L3-L4, and iatrogenic pars defect at L3–left.
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The patient underwent an XLIF at L3-L4 with percutaneous pedicle screw instrumentation left side L3-L4.
Figure 3A: Post-op AP lumbar x-ray
Figure 3B: Post-op lateral lumbar x-ray
The patient went home post-op day 1. Patient reported resolution of LBP, with self-reported pain declining from 7 out of 10 pre-op, to 2 out of 10 post-op. The patient was weaned off narcotic pain killers and occasional non-steroidal anti-inflammatory drugs (NSAIDs). Radiographs indicated a solid interbody fusion. The patient is now 2 years post-op.
This case illustrates the phenomenon of chronic low back pain (LBP) following laminectomy due to iatrogenic instability. Lumbar spinal stenosis is a well-known diagnosis, and surgery is laminectomy with partial facet excision to decompress the central canal and lateral recess.
The key to successful spinal stenosis surgery is adequate decompression while maintaining stability of the spine. Laminectomy alone rarely results in instability unless the patient has pre-operative instability or deformity such as spondylolisthesis, kyphosis, or scoliosis. In these patients with pre-operative instability, fusion and stabilization probably should accompany decompression.
Partial facet excision to decompress the lateral recess is not well defined in the literature, and surgeons have varying techniques of lateral recess decompression. It is important to preserve the facet capsules in all cases, and undercutting of the superior facet should be done to preserve the integrity of the facet joint. No more than 50% of the facet joint should be removed in the majority of the cases unless there is significant foraminal stenosis. Also, the laminectomy should be narrower going from caudal to cephalad as the upper lumbar motion segments have the narrower horizontal pars to pars distance.
It is not unusual to encounter iatrogenic pars fractures following laminectomy. If the patient has significant LBP following laminectomy, flexion-extension radiographs should be done to rule out post-laminectomy instability. The treatment for post-laminectomy instability is fusion and stabilization if conservative treatment fails to relieve the patient's symptoms satisfactorily.
Non-operative pain management is an option but a long course of physical therapy, pain medications, narcotics, etc. can be costly, ineffective, and may cause side effects such as drug dependency. It also prolongs the patient’s suffering. Spinal cord stimulator is a reasonable option for patients without nerve root compression and structural instability, and I would not recommend this therapy for this type of patient.
The treatment that was provided by Dr. Timothy Yoon is a fusion and stabilization method via minimally invasive approach. Alternatively, posterolateral fusion with pedicle screw instrumentation could have been performed, which is a posterior-only approach rather than an anterior and posterior approach. Whatever method is used, the surgeon should be familiar with the technique and provide a sound biomechanical construct and fusion environment.
Lastly, newer methods should be more extensively studied by clinical trials before wide use, and comparative studies on different techniques will give more insights on the advantages, disadvantages, complications, and cost-benefit.
Author’s Concluding Comments
This patient had a known complication of lumbar laminectomy, iatrogenic facet instability. This can happen with over-aggressive pars resection or facet excision during the lumbar laminectomy. Unfortunately, the situation was aggravated because it was not diagnosed by the first surgeon and the patient was deemed to be a chronic low back pain complainer and simply sent away to the pain management physician. This patient was diagnosed with “post-laminectomy syndrome.” While the spinal cord stimulator may have helped with the perception of back pain, it did not and would not address the main pain generator, the instability at L3-L4. There are many acceptable ways of treating this patient surgically. XLIF was chosen because it is minimally invasive and ideal for L3-L4. While many surgeons are performing stand-alone XLIF fusions, I felt that screws posterior to stabilize the deficient facet at L3-L4 would be beneficial for the fusion. By placing percutaneous screws, I was able to do both the anterior and posterior surgeries in a minimally invasive manner.