Lumbar Spinal Stenosis and Neurogenic Claudication: Decompression and Motion-Preserving Stabilization Protocols

Lumbar Spinal Stenosis (LSS) is the leading indication for spine surgery in adults over the age of 65. As the lumbar spine undergoes decades of mechanical wear, disc height loss triggers a cascade of compensatory changes: facet joints hypertrophy (enlarge), osteophytes (bone spurs) form along vertebral margins, and the ligamentum flavum thickens and buckles into the spinal canal. The resulting mechanical narrowing chokes the neural elements within the central canal, lateral recesses, and neural foramina.

Clinically, this manifests as neurogenic claudication—a hallmark syndrome of progressive heaviness, burning, cramping, and numbness in the buttocks, thighs, and calves that worsens with standing and walking, but resolves when leaning forward or sitting. Patients often adopt a hunched posture or lean over grocery carts (“shopping cart sign”) to open up the narrowed canal.

Historically, the surgical remedy for multi-level stenosis was a wide, unconstrained open laminectomy, frequently paired with multi-level pedicle screw instrumentation and fusion. While this cleared the canal, wide bone and facet resection often created iatrogenic spinal instability, while rigid fusion sacrificed lumbar motion, accelerated adjacent-level breakdown, and imposed prolonged recoveries.

In South Florida, Dr. Evan Trapana is a fellowship-trained orthopedic spine surgeon and Assistant Professor of Orthopaedic Spine Surgery at the University of Miami Miller School of Medicine and UHealth Tower. Having completed his orthopedic surgery residency at the University of Miami/Jackson Memorial Hospital and advanced spine surgery fellowship training at the University of California San Diego (UCSD) Medical Center, Dr. Trapana specializes in minimally invasive spine surgery (MISS) and motion-preserving spine reconstruction. By employing targeted microscopic bilateral decompression via unilateral laminotomy (“over-the-top” decompression) alongside motion-preserving interlaminar stabilization, Dr. Trapana relieves claudication symptoms while maintaining the spine’s natural kinematics.

Pathoanatomy: The Triad of Lumbar Canal Constriction

Lumbar central stenosis and lateral recess stenosis develop through three overlapping degenerative processes:

[DEGENERATIVE DISC COLLAPSE]

(Loss of hydration & disc height, circumferential annular bulging)

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[FACET JOINT OVERLOAD & HYPERTROPHY]

(Facet arthrosis, capsular thickening, osteophyte projection into lateral recess)

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[LIGAMENTUM FLAVUM HYPERTROPHY & BUCKLING]

(Loss of elastin, increased collagen deposition, forward redundant folding)

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[CIRCUMFERENTIAL SPINAL CANAL CONSTRICTION]

(Thecal sac cross-sectional area reduced from normal >100 mm² to critical <75–50 mm²)

• Central Canal Stenosis: The primary thecal sac housing the cauda equina is circumferentially squeezed. Cross-sectional canal area shrinks below critical thresholds, causing baseline venous congestion of the nerve roots.
• Lateral Recess Stenosis (“Trefoil Canal”): The exiting nerve root is pinched in the lateral gutter between the superior articular process (SAP) of the facet joint and the posterior vertebral body wall before reaching the foramen.
• Foraminal Stenosis: Loss of intervertebral disc height collapses the vertical height of the exit window, entrapping the nerve root against the pedicle above.

Neurogenic vs. Vascular Claudication: Diagnostic Differentiation

Because lumbar stenosis predominantly affects older adults who often have coexisting peripheral artery disease (PAD), distinguishing between neurogenic claudication and vascular claudication is critical:

Minimally Invasive Decompression: The “Over-the-Top” Unilateral Laminotomy

Traditional open laminectomy required excising the central spinous processes, interspinous/supraspinous ligaments, and entire bilateral laminae, devascularizing the paraspinal musculature and destabilizing the posterior tension band.

Dr. Trapana utilizes a minimally invasive unilateral laminotomy for bilateral decompression (ULBD), also known as the “over-the-top” technique:

[Micro-Incision & Muscle-Splitting Tubular Dilation on Symptomatic Side]

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[Ipsilateral Hemi-Laminotomy & Ligamentum Flavum Resection]

(Direct microscopic decompression of the ipsilateral traversal root)

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[Angling the Tubular Retractor & Operating Microscope Sub-Spinously]

(Drill crosses midline beneath the base of the spinous process)

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[Contralateral “Over-the-Top” Sub-Laminar Undercutting]

(Excises contralateral ligamentum flavum & decompresses opposite lateral recess)

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[360° Thecal Sac Expansion Preserving Supraspinous Ligament & Contralateral Muscle]

1. Muscle-Splitting Approach: Through a 1.5 to 2 cm incision, a tubular retractor is docked on the lamina of the more symptomatic side, preserving the contralateral musculature entirely intact.
2. Ipsilateral Decompression: High-speed diamond burrs and micro-Kerrison rongeurs open the inferior edge of the lamina and excise the hypertrophic ligamentum flavum, widely decompressing the ipsilateral thecal sac and lateral recess.
3. Sub-Spinous Undercutting: The microscope and tube are tilted obliquely. Dr. Trapana drills across the midline beneath the base of the spinous process—undercutting the contralateral lamina without removing the spinous process or the posterior midline ligaments.
4. Contralateral Release: The opposite hypertrophic ligamentum flavum and medial facet osteophytes are peeled away, freeing the opposite nerve root.

Through this single-sided keyhole corridor, both sides of the spinal canal are thoroughly decompressed while leaving the posterior stabilizing column structurally intact.

Motion-Preserving Interlaminar Stabilization (The coflex® Protocol)

When central stenosis is accompanied by mild mechanical instability (such as a stable Grade I degenerative spondylolisthesis) or facet arthropathy, a decompression alone may risk progressive postoperative slip. However, fusing the segment eliminates motion and exposes adjacent levels to increased mechanical stress.

In appropriately selected patients, Dr. Trapana utilizes an interlaminar motion-preserving stabilization device (such as the coflex® implant):

┌──► 1. Maintains Foraminal Height & Decompression

│ (Acts as a dynamic shock-absorbing bumper between spinous processes)

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[MOTION-PRESERVING STABILIZATION] ┼──► 2. Preserves Natural Physiological Motion

│ (Allows flexion, extension, and rotation without fusion rigidity)

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└──► 3. Reduces Adjacent Segment Strain

(Normalizes load transfer without creating rigid stress risers)

• Dynamic Non-Fusion Spacer: Following micro-decompression, a titanium U-shaped implant is inserted between the spinous processes at the affected level.
• Shock Absorption: The device offloads the posterior facet joints and prevents the disc space from collapsing backward during extension, keeping the newly decompressed spinal canal open during standing.
• Mobility Preservation: Because it is anchored to bone without immobilizing fusion rods or bone graft, the segment retains dynamic, physiological range of motion, reducing the risk of adjacent-segment degeneration.

Comparative Overview: Laminectomy vs. Fusion vs. Motion-Preserving Decompression

Patient Candidacy: Who Benefits from Motion-Preserving Stenosis Surgery?

• Ideal Candidates for MISS Decompression ± Motion Preservation:
  • Neurogenic claudication with severe central or lateral recess stenosis on MRI.
  • Patients with back and leg symptoms who find relief when bending forward.
  • Stable Grade I degenerative spondylolisthesis ($< 3\text{ mm}$ translation on dynamic flexion-extension X-rays).
  • Patients seeking to avoid multi-level fusion and its prolonged recovery.
• When Formal Fusion (e.g., TLIF or LLIF) Remains Necessary:
  • High-grade or mobile spondylolisthesis ($> Grade\text{ }I$ or gross instability on dynamic views).
  • Significant degenerative lumbar scoliosis (Cobb angle $> 20^\text{o}$) requiring coronal realignment.
  • Severe preexisting spondylolysis (pars defects).

Conclusion

Lumbar spinal stenosis and neurogenic claudication do not require resigning oneself to a sedentary lifestyle, chronic narcotics, or extensive, mobility-destroying spinal fusions. Through minimally invasive “over-the-top” bilateral decompression and motion-preserving interlaminar stabilization, Dr. Evan Trapana provides patients with targeted relief of leg heaviness and pain, restoring posture, mobility, and independence.

• Surgeon: Dr. Evan Trapana, MD
• Academic Role: Assistant Professor of Orthopaedic Spine Surgery, University of Miami Miller School of Medicine
• Clinical Specialization: Minimally Invasive Spine Surgery (MISS), Motion-Preserving Spine Reconstruction, Tubular Decompression, Robotic Spine Surgery, Complex Spinal Realignment
• Clinical Practice Locations:
  • UHealth Tower (University of Miami Hospital): 1400 NW 12th Ave, Suite 2, Miami, FL 33136
  • UHealth at Coral Gables: 5555 Ponce de Leon Blvd, Coral Gables, FL 33146
• Appointments & Consultations: (305) 243-3000 / (305) 689-4979