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.
Wednesday, November 26, 2008
Monday, November 17, 2008
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.
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.
Monday, November 10, 2008
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.
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.
Sunday, November 2, 2008
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.
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.
Monday, October 27, 2008
Cancer Pain – Indication and Efficacy
Despite our best efforts, advances in treatment and new technology, pain and suffering continues to afflict those with cancer. Even in those who are cured of their cancer, many will experience devastating physical, psychological and financial devastation.
Although the use of opioids to treat cancer pain is more accepted today, there still are many physicians, patients and family members that are fearful of using opioids because of concerns for addiction, side effects, and religious implications
Pharmacological therapy continues to be the primary method for controlling cancer pain. In fact, the use of non-opioid and opioid analgesics along with adjuvant medications can adequately control the pain in 85% of cancer patients. The World Health Organization (WHO) developed a three-step approach in treating malignant and chronic benign pain. This approach, along with medications to treat the side effects from opioids (namely nausea, constipation, pruritis and sedation), has been effective in controlling cancer pain.
In cancer pain refractory to pharmacological management (15% of cancer patients have unrelieved pain or drug side effects), invasive methods of pain control, such as intrathecal pump drug delivery (IPDD), have been successful in reducing pain and drug toxicity.
Smith et al (Curr Oncol Rep 6:291-296,2004) evaluated 202 patients with a VAS =7.5 and taking = 200 mg morphine or opiod equivalent in a prospective, randomized study. The patients were divided into IPDD and medical management groups. The IPDD patients had better clinical success with lower pain (52% vs. 39%), lower drug toxicity (50% vs. 17%) and lived longer when compared to the medical group. IPDD also lower pain by 27% and lower drug toxicity by 50% in the most refractory of cancer patients who first failed to experience any improvement in the medical group.
Sunday, October 19, 2008
Low Back Pain – Do's, Don'ts and Red Flags
Low back pain (LBP) is the second most common reason, other than having a cold, that we seek medical care. Approximately 90% of us will suffer a significant episode of LBP in our lifetime. LBP is the leading cause for disability under the age of 45 and second for those over 45.
The good news is that nine out of ten patients will recover from their back pain within four weeks with or without treatment. Tips (DO'S) to prevent back pain include:
* Lift with the legs not the back
* Do not lift heavy objects
* Wear low heeled shoes
* Get consistent sleep
* Shift heavy purses/briefcases
* Stop activity that hurts
* Do not stoop, and
* Exercise regularly.
Low back pain typically is due to injuries of the soft tissue structures, spinal joints, or discs. Risk factors (DON'TS) for developing low back pain include: poor posture, repetitive motion, prolonged sitting/standing, smoking, poor nutrition, and incorrect bending, lifting, and twisting.
Seek medical attention if your pain does not improve or if it increases over a period of two to three weeks. In addition, you should seek immediate medical care for any of the following RED FLAGS:
* Sudden pain onset if > age 50 O LBP related to a fall or trauma
* Sciatica (leg pain)
* Loss of bowel or bladder control
* Loss of groin or rectal sensation
* Leg weakness
* Falling when walking
* Fever or weight loss, and
* LBP worse at night.
The good news is that nine out of ten patients will recover from their back pain within four weeks with or without treatment. Tips (DO'S) to prevent back pain include:
* Lift with the legs not the back
* Do not lift heavy objects
* Wear low heeled shoes
* Get consistent sleep
* Shift heavy purses/briefcases
* Stop activity that hurts
* Do not stoop, and
* Exercise regularly.
Low back pain typically is due to injuries of the soft tissue structures, spinal joints, or discs. Risk factors (DON'TS) for developing low back pain include: poor posture, repetitive motion, prolonged sitting/standing, smoking, poor nutrition, and incorrect bending, lifting, and twisting.
Seek medical attention if your pain does not improve or if it increases over a period of two to three weeks. In addition, you should seek immediate medical care for any of the following RED FLAGS:
* Sudden pain onset if > age 50 O LBP related to a fall or trauma
* Sciatica (leg pain)
* Loss of bowel or bladder control
* Loss of groin or rectal sensation
* Leg weakness
* Falling when walking
* Fever or weight loss, and
* LBP worse at night.
Sunday, October 12, 2008
Osteoporosis – Diagnosing and Treating
The most common method of diagnosing osteoporosis is via a DEXA (Dual Energy X-ray Absorptiometry) scan. Osteopenia, osteoporosis and severe osteoporosis are respectively defined as DEXA scan T scores of -1 to -2.5, less than -2.5 and less than -2.5 with a fragility fracture.
Vertebral compression fractures are the most common complication of osteoporosis at a cost of 10 to 15 billion dollars every year. There are approximately 700,000 vertebral compression fractures per year in the United States that result in spinal deformity (kyphosis/lordosis), acute/chronic pain, disability and reduced vital respiratory capacity. An osteoporotic vertebral compression fracture should be considered in anyone over the age of fifty with a complaint of acute or chronic back pain. The most common location for vertebral compression fractures are at the T7-8 and T12-L1 levels which correspond to the most mechanically compromised spine regions. The diagnostic work up for someone suspected of having a spinal compression fracture includes spine x-rays looking for wedged shaped vertebral fractures as well as MRI imaging with T2 and STIR sequences to evaluate the acuity of the fracture. Nuclear bone scans and CT can also be helpful in evaluating vertebral compression fractures.
Vertebral compression fractures lead to decreased physical function, restricted activities of daily living, sleep disturbances, early satiety, psychological disturbances and reduced pulmonary function. The subsequent risk of additional vertebral fractures increased after the first fracture. Women with a vertebral fracture had a >20% higher mortality rate adjusted for age. Patients with vertebral fractures are 2-3 times more likely to die of pulmonary causes typically due to COPD and pneumonia complications.
Kyphoplasty is a minimally invasive percutaneous procedure that restores vertebral body height, provides fracture stability and reduces pain associated with vertebral compression fractures. The procedure involves the placement of a balloon catheter through a needle introducer into the vertebral fracture, inflation of the balloon (which creates a cavity and restores vertebral body height) and injection of cement into the cavity. The indications for kyphoplasty include an osteoporotic or malignant spinal compression fracture, persistent back pain, progressive vertebral collapse, spinal deformity and a correct diagnosis from imaging studies. Contraindications consist of bone retropulsion with neurological complications, infection and greater than 80% loss of vertebral body height. Clinical studies have demonstrated that kyphoplasty is a highly effective treatment for compression fractures and provides correction of spinal deformities with significant pain relief, improved quality of life and increased physical function.
Vertebral compression fractures are the most common complication of osteoporosis at a cost of 10 to 15 billion dollars every year. There are approximately 700,000 vertebral compression fractures per year in the United States that result in spinal deformity (kyphosis/lordosis), acute/chronic pain, disability and reduced vital respiratory capacity. An osteoporotic vertebral compression fracture should be considered in anyone over the age of fifty with a complaint of acute or chronic back pain. The most common location for vertebral compression fractures are at the T7-8 and T12-L1 levels which correspond to the most mechanically compromised spine regions. The diagnostic work up for someone suspected of having a spinal compression fracture includes spine x-rays looking for wedged shaped vertebral fractures as well as MRI imaging with T2 and STIR sequences to evaluate the acuity of the fracture. Nuclear bone scans and CT can also be helpful in evaluating vertebral compression fractures.
Vertebral compression fractures lead to decreased physical function, restricted activities of daily living, sleep disturbances, early satiety, psychological disturbances and reduced pulmonary function. The subsequent risk of additional vertebral fractures increased after the first fracture. Women with a vertebral fracture had a >20% higher mortality rate adjusted for age. Patients with vertebral fractures are 2-3 times more likely to die of pulmonary causes typically due to COPD and pneumonia complications.
Kyphoplasty is a minimally invasive percutaneous procedure that restores vertebral body height, provides fracture stability and reduces pain associated with vertebral compression fractures. The procedure involves the placement of a balloon catheter through a needle introducer into the vertebral fracture, inflation of the balloon (which creates a cavity and restores vertebral body height) and injection of cement into the cavity. The indications for kyphoplasty include an osteoporotic or malignant spinal compression fracture, persistent back pain, progressive vertebral collapse, spinal deformity and a correct diagnosis from imaging studies. Contraindications consist of bone retropulsion with neurological complications, infection and greater than 80% loss of vertebral body height. Clinical studies have demonstrated that kyphoplasty is a highly effective treatment for compression fractures and provides correction of spinal deformities with significant pain relief, improved quality of life and increased physical function.
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