Interspinous Process Devices Do Not Reduce Intervertebral Foramina and Discs Heights on Adjacent Segments

Area of Science:

• Spinal surgery
• Orthopedics
• Neurosurgery

Background:

• Lumbar spinal stenosis is a common condition causing nerve root compression.
• Interspinous process devices (IPDs) offer a less invasive surgical option for lumbar stenosis.
• IPDs aim to decompress neural elements by increasing intervertebral foramina and canal space.

Purpose of the Study:

• To evaluate structural changes in the lumbar spine following IPD implantation.
• To assess the impact of IPD placement on operated and adjacent spinal segments.
• To correlate structural changes with clinical outcomes in patients with lumbar stenosis.

Main Methods:

• Twenty-two patients with lumbar stenosis underwent IPD implantation.
• Preoperative MRI assessed stenosis; postoperative CT scans measured morphometric changes.
• Intervertebral foramina dimensions, interspinous distance, and clinical outcomes (ODI, VAS) were analyzed.

Main Results:

• Significant enlargement of intervertebral foramina diameter (1 mm) and surface area (10 mm²) at the operated level.
• Median interspinous distance increased by 3.5 mm.
• Reduced Oswestry Disability Index and visual analog scale scores for back and leg pain, indicating clinical improvement.

Conclusions:

• IPD placement is an effective treatment for lumbar foraminal and canal stenosis.
• The procedure provides short-term symptom relief via foraminal enlargement and neural decompression.
• IPDs reduce facet joint overload without compromising adjacent segment integrity.