What is the best treatment option for a 55-year-old female with chronic radicular low back pain, spinal stenosis, and degenerative disc disease, who has failed conservative treatment and has significant stenosis and instability of the spine?

Surgical Decompression and Fusion is the Appropriate Treatment

For this 55-year-old female with multilevel spinal stenosis, bilateral L5 pars defects with anterolisthesis, and persistent radicular pain despite comprehensive conservative management, the proposed L3-S1 laminectomy and fusion with instrumentation is medically necessary and represents the standard of care. 1

Why Surgery is Indicated

This patient has exhausted appropriate conservative treatment and meets clear criteria for surgical intervention:

• Failed comprehensive conservative management including physical therapy, gabapentin trial, epidural steroid injections, and muscle relaxers over an extended period 2, 1
• Progressive neurological symptoms with weakness in the left leg, worsening nighttime pain, and radicular symptoms extending to the calf 2
• Documented structural pathology on MRI showing severe bilateral foraminal stenosis at L5-S1, moderate stenosis at L4-5, and anterolisthesis of L5 on S1 with bilateral pars defects 1
• Functional impairment with inability to lift the left leg and significant quality of life deterioration despite conservative measures 1

The natural history of lumbar disc herniation with radiculopathy typically improves within 4 weeks with conservative management, but this patient has persistent and worsening symptoms beyond that timeframe, making her an appropriate surgical candidate. 2

Why Fusion is Necessary (Not Just Decompression Alone)

Fusion is specifically indicated in this case due to documented instability from bilateral L5 pars defects with anterolisthesis. 1 The presence of spondylolisthesis represents a Grade B indication for fusion in addition to decompression. 1, 3

Key factors supporting fusion:

• Bilateral pars defects create inherent instability that will not be addressed by decompression alone 1
• Anterolisthesis at L5-S1 represents documented spinal instability requiring stabilization 1, 3
• Multilevel stenosis requiring extensive decompression (L3-4, L4-5, L5-S1) increases the risk of iatrogenic instability if fusion is not performed 1, 4
• Surgical decompression with fusion is recommended as effective treatment for symptomatic stenosis associated with degenerative spondylolisthesis with Grade B evidence 1, 3

Decompression alone in the setting of spondylolisthesis and pars defects carries a 37.5% risk of late instability development and potential need for revision surgery. 3

Why the Proposed Multilevel Construct is Appropriate

The L3-S1 fusion construct is justified by:

• Contiguous multilevel stenosis at L3-4, L4-5, and L5-S1 all contributing to symptoms 1
• Severe bilateral foraminal stenosis at L5-S1 requiring extensive decompression that would destabilize the segment without fusion 1
• Moderate stenosis at L4-5 with bilateral involvement requiring decompression 1
• Left lateral recess stenosis at L3-4 correlating with radicular symptoms 1

Each level independently meets criteria for surgical intervention based on imaging findings that correlate with clinical symptoms. 1

Instrumentation and Interbody Cages are Standard of Care

The proposed pedicle screw instrumentation with PEEK interbody cages at L4-5 and L5-S1 represents appropriate surgical technique:

• Pedicle screw fixation provides optimal biomechanical stability with fusion rates up to 95% compared to significantly lower rates without instrumentation 1
• Interbody fusion techniques demonstrate higher fusion rates (89-95%) compared to posterolateral fusion alone (67-92%) in patients with degenerative disc disease and spondylolisthesis 1
• Combined anterior-posterior approaches (interbody cages plus posterolateral fusion) provide superior stability, particularly important given the instability from pars defects 1

Use of Bone Morphogenic Protein is Supported

The inclusion of bone morphogenic protein (BMP) in the fusion construct has Grade B evidence supporting its use as a bone graft extender in instrumented posterolateral fusions. 1 However, the surgeon should be aware that BMP carries a 14% incidence of postoperative radiculitis, which can be reduced to 5.4% with use of hydrogel sealant to shield the exiting nerve root. 1

Critical Pitfalls to Avoid

• Do not delay surgery further - this patient has already completed appropriate conservative management and has progressive neurological symptoms including weakness 2, 3
• Do not perform decompression alone - the presence of spondylolisthesis with pars defects is an absolute indication for fusion to prevent late instability 1, 3
• Do not limit fusion to only L5-S1 - all three levels (L3-4, L4-5, L5-S1) have significant stenosis requiring decompression, and extensive multilevel decompression without fusion carries substantial risk of iatrogenic instability 1, 4
• Ensure inpatient admission - multilevel instrumented fusion with extensive bilateral decompression requires inpatient monitoring for neurological complications, pain management, and early mobilization due to complication rates of 31-40% for multilevel instrumented procedures 1, 3

Expected Outcomes

With appropriate surgical technique, this patient can expect:

• Clinical improvement in 86-92% of patients undergoing interbody fusion for degenerative pathology 1
• Fusion rates of 89-95% with combined interbody and posterolateral fusion using instrumentation 1
• Significant reduction in radicular pain and back pain compared to continued conservative management 1
• Resolution of neurogenic claudication in the majority of cases 1

The presence of multiple comorbidities (hypothyroidism, anxiety, depression, hyperlipidemia) requires optimization but does not contraindicate surgery given the severity of her spinal pathology and failed conservative management. 1