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Interspinous Process Fusion Surgery

  • Category: Back Surgery
  • Posted On:
  • Written By: DR. HAMID ABBASI

Interspinous process fusion surgery is a technique used to treat spinal stenosis, which occurs when the nerves passing through a narrowed spinal canal become compressed. The pressure leads to back pain and radiculopathy, which involves leg symptoms of tingling, pain, numbness, and weakness. Spinal stenosis occurs with aging, back injury, or trauma.

What is an interspinous process fusion device?

The interspinous process device is designed to open the foramen, which is the spinal component where the nerve endings pass from the center of the cord outward to the body region. By passing your hand down your spine you can feel small bony prominences, which are called the spinous processes. The interspinous process spacer device unloads the intervertebral disc, and improves the space where the nerves roots exit foraminal openings.

How is the procedure performed?

When you arrive at the surgical center, a nurse places an intravenous catheter in your arm to administer anesthesia medications. Once you are asleep, you are positioned face down a special table. The doctor will clean the area using an antiseptic solution. An interspinous process fusion surgery involves making a small incision of the back directly over the spine, and removing a small amount of soft tissue and bone. The removal of bone and tissue is called decompression, which is done to reduce pressure on associated spinal nerves.

A bone graft is implanted to stabilize the spine and maintain the decompression of the spinal cord and nerves. The bone graft eventually fuses the vertebrae together. During the first step of the procedure a metal plate is affixed to the affected vertebra component. This will prevent motion between the two spine bones and maintain stability of the spinal column. After debris is removed using irrigation and suctioning, the incision is closed using sutures.

What are the benefits of interspinous process fusion?

Compared to the traditional spinal fusion techniques, interspinous process fusion for lumbar spinal stenosis has many benefits. These include:

  • Improved spine stability
  • Lasting pain relief
  • Minimal damage to surrounding tissue and structures
  • Increased mobility following surgery
  • Immediate reduction in pain
  • Improve neurological symptoms

Who is a candidate for interspinous process fusion?

People with mild to moderate lumbar spinal stenosis are good candidates for the interspinous process fusion procedure. The surgeon will first want to try non-surgical measures, such as activity modification, exercise, and epidural steroid injections. To have this surgery, the patient must have documented failure on usual treatment efforts. In addition, ideal candidates will be in good general health and not suffer from any conditions that will affect usual recovery.

Does interspinous process fusion alleviate the symptoms of lumbar spinal stenosis?

Lumbar degenerative spinal stenosis affects the facet joints and narrows the spinal canal, which results in nerve root compression. In a recent study, 30% of the general population suffered from stenosis, which mainly affects older persons. In a randomized controlled trial, researchers evaluated whether interspinous process fusion was more effective than conventional surgical decompression for patients with symptomatic lumbar spinal stenosis. The study outcomes were short-term (8 weeks) and long-term (12 months) follow-up using Zurich Claudication Questionnaire scores. The researchers found that the procedure had a 70% success rate.

How long is the recovery and rehabilitation period?

After surgery, you will stay over for 1-4 days, depending on your procedure, your general health, and your surgeon’s preference. A physical therapist begins working with you to get in and out of bed and to use the assistive walking device. You must keep your incisions clean and dry after going home, so avoid soaking in tub. Showering is permitted, but you should cover your incisions with bandages. Arrange to have transportation home from the hospital, and someone needs to take you to and from doctor’s appointments and the pharmacy.


Moojen WA, Arts MP, Jacobs WCH (2013). Interspinous process device versus standard conventional surgical decompression for lumbar spinal stenosis: randomized controlled trial. BMJ, 347, 6415.