I commonly counsel my patients on the etiology, or cause, of their low back pain and potential treatments and therapies. The medical treatment spectrum ranges from conservative to invasive or surgical. Many times, it starts with physical therapy, analgesics, activity modification, and modalities such as heat and ice. A pain management physician can order and oversee this end of the spectrum. If conservative treatments fail to alleviate the pain syndrome, a pain physician may assess the need for interventional pain therapies. Such therapies are minimally invasive and seek to treat the underlying pain generator. Common pain generators for low back pain include the discs, facet joints, spinal nerves, and vertebral bodies. Discogenic pain involves pain to the lower back (axial pain) due to problems with the intervertebral disc. Disc displacements such as disc bulges, herniations and extrusions may be the initial culprit in producing low back pain syndromes.
In many cases lumbar epidural steroid injections may help reduce the inflammatory cascade seen in disc displacement disorders. In the event the disc impinges upon the exiting spinal nerves, it may lead to neuropathic or nerve pain down the extremity. Although this is commonly referral to as “sciatica,” the medical classification is lumbar radiculopathy. In lumbar radiculopathy, the leg pain typically radiations down the leg in a dermatomal distribution. When an interventional pain treatment such as an epidural steroid injection is employed, it is thought to help stabilize the spinal nerve, thereby reducing the shooting leg pain syndromes typical of lumbar radiculopathy.
Lumbar spondylosis is a term that serves as a catch all for degenerative conditions of the spine. It may involve degeneration of the discs, spinal stenosis, facet arthropathy, and spondylolisthesis. Spondylosis may include osteoarthritic changes of the facet joints. The facet joints are important for mechanical mobility, for example, twisting of the lumbar spine. Therefore, the facet joints are crucial to our activities of daily living (ADLs). Arthropathy of the facet joints may lead to bone spurs and arthritic overgrowth of the facet joint. This, in many cases, may led to compression of the spinal nerves causing neuroforaminal stenosis. This is stenosis or narrowing at the exit holes for the spinal nerves. Stenosis may also be of a central or spinal canal variety. Central spinal canal stenosis maybe due to disc displacement or a degenerative process such as spondylosis. Spinal stenosis may lead to neurogenic claudication or nerve pain with walking. Nerve pain or neuropathic pain may present as numbness, tingling, burning, and shooting pain. Minimally invasive implants such as interspinous process devices may lead to indirect decompression of spinal stenosis resulting in improvement of pain from neurogenic claudication. Other minimally invasive treatments such as a dorsal column spinal stimulator may lead to relief of both axial (lumbar) pain and radicular (lower extremity) pain.
Facet joint arthropathy may lead to stiffness as well as axial low back pain. Since there is no treatment to reverse osteoarthritis of the facet joint, this condition like so many other spine conditions will gradually worsen. A review of spinal anatomy demonstrates that a sensory nerve (lumbar medial branch nerve or facet nerve) supplies the facet joints. Each facet joint is supplies by two facet nerves. Without having to perform an open surgery, interventional pain procedures exist to ablate this sensory nerve and remit pain from facet arthropathy. This procedure is called radiofrequency ablation of the medial branch nerve or rhizotomy of the facet joint nerve. In many cases, this non-surgical procedure leads to twelve months or greater pain relief.
Modic changes in the vertebral bodies are inflammatory end-plate changes found on MRI studies. These changes are associated with axial low back pain. Vertebrogenic pain is amenable to treatment by radiofrequency ablation of the basivertebral nerve (BVN). This procedure may result in several years of axial low back pain improvement.
If interventional pain procedures help remit low back pain, a pain physician may help ensure the patient knows proper body mechanics and is empowered with a home exercise program to help protect the spine from further degeneration. If minimally invasive interventional pain procedures fail to provide pain relief and improvement in activities of daily living, a pain physician may consult with a spine surgeon. A spine surgeon may provide more invasive surgical options. Regardless of the treatments employed, I advise my patients that we will work as a team to detail and treat each pain generator to alleviate pain, but more importantly, to improve function and hence quality of life.