Neural foramina are small canals at every level of the spine through which nerves leave the spinal cord and go to the limbs and other parts of the body. Narrowing of this canal is called foraminal stenosis. Narrowing may be caused by bone spurs, a herniated or bulging disc, arthritis, ligament thickening or enlargement of a joint in the spinal canal. This puts pressure on the nerve roots causing symptoms that include pain, muscle weakness, muscle spasms, cramping, numbness, and tingling. The symptoms may be felt in the neck, back, shoulders, arms, hands, legs, buttocks, or feet depending on the position of the affected foramen.
Usually, conservative treatment is given which includes rest, moderate exercises like swimming, walking and stretching to strengthen the back, medications for relieving pain and inflammation, physical therapy and hot/cold therapy. For severe pain, epidural injection of corticosteroids may be recommended in some cases. Only when conservative treatment provides little or no relief, surgery is recommended. Surgery aims at removing the overgrown tissue such as scar tissue, bulging disc and bone spurs thereby enlarging the canal and relieving pressure on the nerves. Traditionally, surgery for foraminal stenosis involved open spine surgery. Open spine surgery is performed through a large incision and involves extensive muscle and soft tissue dissection and removal of a portion of spinal bone to access the affected compressed nerve root. In some cases, it leads to spinal instability and requires another procedure called a fusion, to stabilize the spine. Fusion involves placement of bone grafts, screws, and rods to permanently fuse the two vertebrae into one solid bone.
Open spine surgery is thus highly invasive and takes a long recovery time of about a year. With the advent of minimally invasive spine surgery techniques, foraminal stenosis surgery can now be performed by a newer procedure called endoscopic foraminoplasty.
Endoscopic foraminoplasty is performed through a small incision on the back near the compressed nerve root. To access the spine, muscles are not cut but are moved aside with telescoping tubes that are inserted into the incision down to the compressed nerve root. Next, an endoscope (a thin flexible telescope) and tiny surgical tools are inserted through the tubes. The portion of disc or bone material causing pressure on the nerve is removed by manual reamers, powered reamers and laser resection to restore foraminal volume. This reduces the pressure on the nerves and relieves the pain. The surgery is usually performed on an outpatient basis and the patient can return home the same day as the surgery. Recovery is much quicker as compared to the open spine surgery.
Apart from the above listed benefits, endoscopic foraminoplasty also provides additional benefits that include:
- Small incision and less scarring
- No or little blood loss
- Does not cause spinal instability
- Usually done under local anesthesia thus the risks of general anesthesia is avoided
- Can be performed in medically high risk patients and obese
- Can be performed in multiple levels in the same procedure
- Physical therapy can begin the same day as the surgery
- Less postoperative pain
- Less risk of infection