Surgical Interventions

In the United States 11,000 new injuries occur each year. A significant number of these injuries require some type of surgery in the acute phase. Occasionally, people with chronic injuries will also require spinal surgery. Surgical management of both acute and chronic SCI is still evolving. An ongoing goal of Miami Project research is to evaluate current surgical strategies and intra-operative monitoring designed to protect the nervous system from further damage and to restore or improve remaining neurological function.

Surgical Strategies
Sometimes, after SCI, dislocated vertebrae or bone fragments remain in the spinal column and impair function by putting pressure on the spinal cord tissue. Similarly, scar tissue can cause the spinal cord or its surrounding membranes to "tether" to bone, resulting in loss of function. Surgeons have questioned whether delayed decompression, the surgical removal of pressure on the spinal cord of chronically injured persons, or detethering enhances function after SCI.

They also are interested in evaluating intra-operative procedures to protect the spinal cord during surgical interventions. Hypothermia has been shown to protect the brain and spinal cord from ischemia, or temporary poor blood flow. Miami Project investigators have initiated clinical studies to evaluate if hypothermia used during delicate surgical procedures can reduce the extent of damage in spinal cord injuries.

Miami Project study results showed:

• Detethering and delayed decompression enhanced motor function in 80 percent of patients with compressed or tethered cords. [Abstract]

• Promise that spinal stabilization using a minimally invasive procedure is comparable to conventional invasive procedures [Abstract] and may be advantageous in reducing postoperative pain and shortening hospital stays. [Abstract]
  
• The safety of mild intraoperative hypothermia during surgical decompression of the spinal cord was assessed. Although there has been concern that mild hypothermia might increase surgical blood loss, a recent study found that mild hypothermia was safe and did not increase blood loss. [Abstract]

Intra-operative Monitoring
The spinal cord is encased within the bones of the spinal column (vertebrae), and is attached to peripheral nerve roots that weave through openings between the bones as they travel to and from the rest of the body. Many surgical procedures create a substantial risk of damaging the nerves of the spinal cord. Intra-operative monitoring uses ongoing recordings of nervous system activity during surgery to assess function and detect damage.

Intra-operative monitoring techniques developed by Miami Project scientists have been designed to help protect healthy nerve roots during spinal surgeries. If nerves are undergoing damage or if critical blood flow in the spinal cord is blocked, paralysis could occur within minutes. Intra-operative monitoring informs and guides surgeons immediately if muscle responses decline during the surgical procedure.

Recent Miami Project publications document encouraging findings:

• Miami Project surgeons and physiologists tested, first on animals and then on humans, an intra-operative nerve stimulation technique, and proved it to be effective in predicting and preventing nerve damage during "pedicle surgery" in the lumbosacral (lower back) spinal column. [Abstract]

• Another method using "transcranial electrical stimulation" (TES) and muscle recordings (EMG), allows surgeons to monitor nerve and muscle activity, and has proven to be a simple and accurate technique for reducing the risk of nerve damage during surgery. [Abstract]

Miami Project Faculty working in this area of study

Barth A. Green
James D. Guest
Allan D.O. Levi

Other articles related to this topic

Directors' Summaries
Surgical Spine Interventions: Advancing the Technologies
The Neurosurgeon's Perspective
Clinical Technologies
The Neurosurgeon's Perspective

Research Reviews
Spring 1998: Clinical Studies Yield Important Advances in Surgical Procedures

Summer 1994 Extra: A New Approach to Safer Spine Surgery