Spinal Stenosis – Unresponsive to Nonoperative Treatment
A 65-year old male with multiple medical problems reports a long history of low back and leg pain with difficulty walking upright, especially during the last several months. The patient initially presented to the clinic in a wheelchair because he could not endure the long walk to the clinic from his car. Pain extends from his low back down through the posterior calves. He cannot tolerate prolonged walking or standing.
The patient’s medical history includes: two coronary artery bypass grafts, abdominal aortic aneurysm repair, hypertension, diabetes mellitus, chronic obstructive pulmonary disease and severe familial coronary artery disease (father died at age 33, heart attack).
He is a two pack per day smoker and reports moderate alcohol consumption.
The patient has difficulty standing from a seated position and stands hunched over. He has postural relief of his symptoms by leaning forward. Strength 5/5 with decreased sensation in the left medial calf. He has trace ankle jerk and knee jerk reflexes with downgoing toes.
The patient responded well to epidural steroid injections but they did not provide lasting relief.
Images show severe stenosis at levels L4-S1, secondary to facet degeneration, as well as present lordosis and autofusion at L5-S1.
Figure 1. Sagittal T2 MRI showing severe stenosis at L4-5; preserved lordosis and autofusion of L5-S1
Figure 2. Axial T2 MRI showing severe L4-5 stenosis secondary to facet degeneration and redundant ligamentum flavum
Figure 3. post-op film
Discussion of Treatment Options and Recommendation
This case represents an issue of balancing the relative risks and benefits of a definitive surgical decompressive and/or reconstruction treatment versus more limited options such as an interspinous spacer or nonsurgical treatment. In this case, nonsurgical treatment has been ineffective. Given the patient’s level of disability, this seems to be an unreasonable option in terms of both his disability and overall health.
Patients with pain-related disability typically have deterioration in their overall health scores compared to nonmorbid cohorts. The patient’s medical comorbidity creates high risks of complications with any surgical procedure. The more complex the procedure, the higher the mortality risk. As such, the least invasive procedure considering anesthetic time and physiologic strain is desirable.
Recent data on interbody spacing devices suggest that they can be effective in selected cases. This patient seems to meet these criteria. He has single-level stenosis, pain relieved in flexion, and medical comorbidity that makes standard surgical treatments a daunting process. As such, this is the ideal patient for an interbody spacing device. The one piece of data that we lack here to make a fully rational treatment decision is a 36-inch standing scoliosis radiograph in the upright and supine positions to assess if this patient has an associated fixed sagittal imbalance and if that magnitude is clinically significant (>4.0 to 7.0 cm).
Assuming that the patient’s forward bent posture is due to compensatory pain relief posture and not fixed sagittal imbalance, I would recommend an interbody spacer. The data suggests that this treatment will provide low-risk symptomatic relief. If scoliosis films demonstrate a major fixed sagittal imbalance, I would consider a minimally invasive or other correction of his stenosis and symptomatic fixed sagittal imbalance.
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The selected surgical treatment was an Interspinous Process Decompression® using X-STOP® size 14mm implant placed under local with MAC anesthesia. The patient tolerated the procedure well with minimal blood loss and no further complications. He was discharged the following day.
At the first (6 weeks) and each subsequent return visit, the patient walked into the clinic. At 6 weeks postoperative, he reported his pain was 50% better and also at 3 months postoperative he said his pain was 50% better while he felt walking was 200% better.
On the initial MRI [fig. 1] note that there is no spondylolisthesis at L4-5. On the post-op film [fig. 3] there is clearly a Grade I. Also note on the postop film that there appears to be some hallowing around the implant and significant distraction of the facet. This hallowing was present on the 6-week postop and all subsequent films. As the implanting surgeon, I am concerned I may have used too large of an implant. An oversized implant is a common mistake in this procedure.
This case demonstrates an ideal application of this device with results that support the literature findings. While there are no scoliosis films, this patient is likely forward in sagittal alignment given the lumbar radiograph orientation. It would be important to follow this patient’s long-term results on outcome and overall sagittal alignment to help determine what parameters of balance would make such therapy a poor choice. Clearly, this was the right choice for this patient, at least in the short term. I believe that this technology will be helpful in carefully selected cases but encourage careful assessment of global sagittal alignment in any surgical procedure.