Despite being commonly ascribed as the etiology for back pain, bulging discs are not always the cause. "That which bulges does not necessarily cause pain, and that which causes pain does not necessarily bulge," say many spine specialists. Furthermore, motion segment instability does not inevitably imply pain. Numerous structures containing nociceptors in the lumbar region also make accurate diagnosis extremely difficult. Confounding variables such as work-related injuries, litigation, secondary gain and cultural and psychosocial issues can render the etiology of back pain unidentifiable.
With advances in CT,MRI and three-dimensional reconstruction technology, our ability to visualize the human spine has never been greater. Minimally invasive procedures have greatly enhanced treatment and artificial disc surgery will likely do the same.
Despite this technological progress, back pain remains the great nemesis of physicians throughout the world. The reason: inadequate diagnosis, or failure to identify the true "pain generator."Although previously considered simply a catchy phrase, the idea of the pain generator is now receiving significant attention.
In years past, a diagnosis of lumbar spondylosis or degenerative disc disease was the common endpoint in the diagnostic algorithm for back pain. In contrast, we now have the ability to specifically pinpoint likely offending pain generators, and in many cases tailor management to resolve them.
Guidelines for management
The following are basic guidelines to help physicians identify the etiologies of lumbar spine pain.
Lumbar spine pain falls into two general categories: purely axial, and radicular or radiating. In patients with purely midline or lateralizing low-back pain, common and uncommon etiologies should be considered. These include pain originating from osseous structures (vertebral compression fractures, pars defects, or vertebral instability), soft tissue (ligaments, tendons, muscles and cartilaginous structures), joints (facet joints, intervertebral discs, sacroiliac joints) as well as tumors, infection or other infiltrative processes.
In patients with radicular pain, nerve root lesions (compressive lesions from adjacent discs, hypertrophic facet joints, facet joints cysts, faulty hardware positioning, bony foraminal encroachment caused by spondylolisthesis or spondylolysis, congenitally short pedicles, nerve sheath tumors, granulation tissue and arachnoiditis), spinal nerve compression and peripheral nerve lesions should be considered. Not all radiating pain originates from the spine, and common etiologies such as femoral neuropathy, meralgia paresthetica, peroneal neuropathy, asymmetrical neuropathies, lower limb joint pathology and vascular pathology are often mistaken for radicular pain in patients with and without radiographic evidence of degenerative disc and joint disease.
Where to begin
Accurate assessment of lumbar spine pain should begin with a thorough history, addressing location, duration of symptoms, quality, intensity and exacerbating and ameliorating factors. Red flags, such as fever, unexplained weight loss, recent trauma, bladder or bowel dysfunction, history of carcinoma, disturbance of gait, saddle anesthesia, progressive neurologic deficits, age of onset less than 20 or greater than 55 years of age and comorbid conditions, should be investigated.
Physical examination should assess for structural abnormalities, reproducibility of pain, neurologic deficits, evidence of systemic pathology and the patient's response to pain. Range of motion and resulting pain, tissue texture changes, strength, reflexes and sensation even in patients with mild symptoms should be evaluated. Provocation of nerve root tension signs produces a fairly accurate diagnosis of significant radiculopathy. Finally, physicians should assess the appropriateness of the patient's reaction to pain using Waddell's Test. The presence of two or more of the following findings correlates with poor surgical outcome: overreaction during exam, lumbar pain elicited with axial loading from examiner's hand pressing on patient's head, negative exam findings during distractions, lack of reproducibility, severe pain during superficial palpation, or non-anatomical motor or sensory distributions.
Diagnostic tools
Although easy to obtain and relatively inexpensive, standard X-ray studies should not be ordered within the first four weeks of acute back pain in the absence of red flags or high suspicion for fractures, tumors or other bony pathology. With persistent back pain unrelieved by several weeks of conservative care or in the presence of significant red flags, high suspicion for fracture, evidence of neurologic changes, night pain and or weight loss, X-rays are clearly indicated.
Radiographic findings must be carefully correlated with physical exam findings and not relied upon too heavily in order to prevent inadvertent misdiagnosis and inappropriate treatment. MRI or CT should be ordered in the presence of red flags, persistent neurologic changes, neurogenic claudication suggesting spinal stenosis, symptoms suggesting significant spinal pathology and when interventional procedures or surgery are being considered. Bone scans can help diagnose acute compression or occult fractures and bony destructive lesions.
In clearly evident radiculopathy, electrodiagnostic studies need not be ordered. But many times EMG/nerve conduction studies help differentiate between nerve root, peripheral nerve lesions and underlying neuropathy in patients with radiating pain. They should not be ordered within the first two weeks of symptoms.
Interventional spine specialists narrow in on pain generators and treat pain using selective nerve blocks, facet joint blocks, medial branch blocks, sacroiliac joint injections and discography.
When to refer
Referral to a spine specialist is warranted if initial evaluation and work up are inconclusive; in patients whose pain persists beyond two to four weeks despite conservative care with NSAIDS, analgesics and therapy; in patients with progressing or persistent neurologic symptoms; or in the presence of ominous signs and symptoms suggesting serious spinal pathology.
No single aspect of back-pain management is more important than the accurate diagnosis of the pain generator. Without it, even the most advanced treatments cannot be appropriately applied. Only after the pain generator has been identified should any aggressive surgical or irreversible treatment measures be taken. It is time we adopt a more systematic approach to the diagnosis of back pain.
Spinal Column, Fall 2004. Cleveland Clinic Spine Institute (CCSI).
Copyright @2004. Cleveland Clinic Foundation. All Rights Reserved.
Fall 2004 CCSI
发自我的 iPhone
Keine Kommentare:
Kommentar veröffentlichen