Low Back Pain and The Zygapophysial Joint

Imaging Studies
One must recognize that imaging studies only provide anatomic detail and cannot independently determine the particular source or cause of pain. There are no radiographic studies available at present to conclusively diagnose L-z-joint pain. Various studies may reveal anatomic abnormalities of the lumbar spine. However, they are not diagnostic. Due to the fact that pain is a subjective experience, the spine physician must carefully assess the history and correlate it with the imaging studies. Use of plain radiographs, CT, CT myelography, MRI, bone scans and SPECT can be utilized to provide additional anatomic detail. They can also alert the physician of the more malignant causes of low back pain.

Diagnostic Injection
Reproducible analgesia after L-z-joint injection is an accepted method to confirm the clinical suspicion of L-z-joint pain. Therefore, fluoroscopically guided L-z-joint injections with a local anesthetic agent is more commonly utilized for isolating or excluding the L-z-joint as the source of back and leg pain. However, it has not been accepted as a true gold standard for L-z-joint pain. Spine physicians may use intra-articular or medial branch blocks for the diagnostic work up. Obtaining pain relief is suggestive of the fact that the injected joint is, indeed, the pain generator. Pain relief following the blockade of the nocioceptor fibers implies the blocked structures were the true source of pain. However, subjective analgesic blocks rely on the patient's response, and are prone to false positive responses. False positive responses may be eliminated when a control injection is employed. Patients who accurately report differing durations of analgesia with different anesthetic agents are considered to be true responders.

Treatment
Various treatment options are available for L-z-joint pain. Conservative care options include oral medication, physical therapy and therapeutic injections, which are minimally invasive. Physicians may use non-narcotic analgesic medication for the treatment of L-z-joint pain. However, prolonged narcotic analgesics should not be used. The use of anti-depressants in low doses may help regular sleep cycles. Anti-depressant medications with anti-cholinergic properties should be used with caution, especially in the elderly. Dry mouth, urinary retention, constipation, blurred vision and exacerbation of glaucoma can be a serious problem in this population. Particular attention should be paid to mental clouding, somnolence and orthostatic hypotension.

Some may find temporary relief with TENS or muscle stimulators and others will find relief with traction of the lumbar spine. Traction should be used with caution as it may cause worsening of the pain in acute conditions. Water based exercises can also be instituted for relief of L-z-joint pain. Education and training in proper body mechanics and posture are crucial. Physicians who care for back pain patients must have short term and long term goals. These should include the elimination of pain, a return to baseline function, normal and pain free range of motion, normal strength and flexibility and education for prevention of injuries in the future. Patients should be independent with a home exercise program.

Patients who do not respond to conservative care should undergo diagnostic L-z-joint blocks. Those who do respond to these injections should undergo therapeutic blocks. If the effects are satisfactory, but temporary, radio-frequency ablation is an option. These options should be used with caution. Patients may consider surgical fusion. However, most studies do not support this option as a common means for treatment of L-z-joint pain. Once a patient presents with low back pain, the physician should entertain all the spinal and nonspinal causes of pain. Once L-z-joint pain is suspected, the patient should undergo an educational program and be treated with the least expensive and least invasive but appropriate techniques. If these approaches do not provide adequate relief of pain, more invasive methods may be used to bring the discomfort of L-z-joint pain under control.