Spinal Cord Stimulation – Treating Radiculopathy and Spine Pain

Spinal cord stimulation (SCS) has been used for controlling intractable back and leg pain for more than 30 years. The SCS system stimulates the dorsal column of the spinal cord by tiny electrical impulses from small electrical wires placed on the spinal cord.

Spinal cord stimulation typically consists of one or two wires with a number of electrodes and a pulse generator or battery. The wire carries the electrical stimulation from the pulse generator or battery to the posterior column of the spinal cord.

Some believe that the stimulation blocks pain transmission through the spinal cord, while others believe there is activation of supraspinal pain inhibition, and still others think there is activation of neurotransmitters or neuromodulators that provide pain relief.

Pain relief from SCS varies therefore all patients considered for SCS must undergo a trial. The trial involves percutaneous placement of the wires with an external power source for five to seven days. The trial is considered successful if the patient reports good pain coverage, stimulation tolerance, pain relief, increased function, and improved sleep. The trial will determine whether or not the patient is a candidate for surgical implantation of a SCS system.

The advent of newer techniques such as retrograde wire placement have improved the efficacy of SCS in the treatment of limb and axial pain. Other applications have been successful in treating pelvic pain, bladder dysfunction, chronic angina pain and headaches.

Radiofrequency Surgery in Pain Management

The advantages of radiofrequency surgery include controlled lesion size, accurate temperature monitoring, limited need for anesthesia, precise probe placement under fluoroscopic imaging, low incidence of morbidity or mortality, and rapid post-procedure recovery. High frequency alternating current causes vibration of the electrons in the tissues in the vicinity of the radiofrequency (RF) probe, resulting in an increase in temperature. Radiofrequency surgery is performed at temperatures between 60 and 90°C depending on the structure that is causing the pain.

This pain management surgical procedure is used to treat a variety of painful conditions, such as chronic neck and back pain, headaches, trigeminal neuralgia, reflex sympathetic dystrophy (RSD), sciatica, facet syndrome, sacroiliac joint dysfunction, TMJ and cancer pain.

The procedure is performed under fluoroscopic guidance to ensure proper positioning of the RF probe. The surgery lasts approximately 30 to 60 minutes depending on the application. Some patients will experience a burning sensation at the surgery site after the procedure that is controlled with medication until it resolves in about three weeks. Nerves can regenerate over a period of one to two years that might require another RF surgery depending on whether or not the pain returns with nerve regeneration and to what degree.

Lumbar Spine Disc Degeneration – Disease or Aging Process

There is confusion as to what constitutes degenerative disc changes from what normally occurs with aging. This often times leads to misinterpretation of normal intervertebral disc and spine aging as findings with degeneration. Fibrous tissue normally replaces the mucoid matrix of the nucleus pulposus over time with aging without leading to a loss of disc height. This is considered to be a non-pathologic aspect of aging that manifests as a small to moderate decrease in the signal intensity of the nucleus pulposus on T-2 weighted MRI images and should be uniformly present throughout the spine.

Intervertebral disc margins do not become irregular as a result of aging alone. Annular pathology, such as isolated radial fissures, are rarely present in those over the age of 40 as a part of normal aging. The presence of small amounts of intradiscal gas on imaging studies is not unusual for older individuals. Osteophytes involving the anterior and lateral margins of the vertebral body are considered a natural part of the aging process whereas the existence of posterior osteophytes and endplate erosions are considered to be degenerative.

Degenerative disc changes begin in response to repetitive micro trauma from eccentric or torsional loading producing early signs of mechanical failure. Tears involving the outer annulus within the region of disc innervation can produce back pain. Circumferential tears eventually coalesce and the nucleus pulposus loses its hydrophilic properties both of which lead to further disc degeneration.

Discogenic Low Back Pain – Underappreciated and Misunderstood

Discogenic low back pain (DLBP) is a common cause for chronic axial back pain that is often unrecognized and misdiagnosed. This occurs because of the lack of objective findings, a low index of suspicion and limitations of imaging studies.

DLBP results from a fissure or tear of the outer annulus that surrounds the disc nucleus.

The fissures or tears can result from trauma such as a slip and fall, MVA, or a lifting, twisting or bending event. The injury leads to intense back pain that can radiate into the buttocks, posterior thigh or sometimes into the groin. The pain is typically higher with sitting, driving, standing, bending or lifting and lower in a recumbent position.

There are few findings on exam such as muscle spasms, painful range of motion and pain with palpation. The neurological exam is normal. Imaging studies are often unremarkable. A "high intensity" finding in the annulus can be present on MRI that has a 90% positive predictive value for DLBP but this finding is present in less than 20% of patients with DLBP.

Discography is the only reliable means of diagnosing DLBP. Contrast is injected into the disc in an attempt to recreate the pain and to detect any annular tears. The contrast injections are followed by a CT scan for a more detailed evaluation.

Primary treatment for DLBP is aggressive PT supplemented with pain medications. Discography is considered in those who fail six months of conservative treatment. Depending on the results, interventional treatment options include an IDET procedure or spine surgery.