Abstract
BACKGROUND
The lumbar spine is a common cause of referred pain to the lower extremities. Standard conservative treatments (i.e., physical therapy and pharmacotherapy) can provide only partial or temporary relief, in which case injections might be used. This often consists of epidural steroid injections to treat possible radicular pain. When symptoms still persist, radiofrequency ablation (RFA) to treat facet-mediated pain can offer a viable option before surgical intervention.
OBSERVATIONS
In this illustrative case, a patient presenting with a complex array of worsening symptoms in the lower extremities, secondary to lumbar spondylosis, was treated using RFA. Conservative treatments resulted in partial, temporary relief. A facet-mediated source of pain was suspected, and diagnostic blocks indicated that the patient would be a candidate for bilateral RFA of the medial branches at L3, L4, and L5. Following the RFA procedure, the patient had full resolution of her lower extremity pain and paresthesias.
LESSONS
RFA procedures are typically performed to address low back pain rather than concomitant lower extremity pain and paresthesias. This case provides evidence indicating that, in the face of appropriate conservative management and diagnostic testing, RFA of the medial lumbar branches can address lower extremity pain secondary to lumbar spine pathology.
Keywords: radiofrequency ablation, medial nerve branch, lumbar spine, lower extremity pain
ABBREVIATIONS: RFA = radiofrequency ablation.
Low back pain is the most prevalent musculoskeletal pathology worldwide. It is a leading contributor to disease burden and disability globally, resulting in activity limitation, employment absenteeism, and a reduction in quality of life.1–3 Studies have suggested that 41% of chronic low back pain is associated with lumbar zygapophysial (facet) joint pain (Z-joint pain), with variation among the literature depending on definition, setting, and diagnostic procedures.4 Standard conservative treatment, including physical therapy and pharmacotherapy, often provides only temporary or partial relief.5 Since its introduction in 1975, radiofrequency ablation (RFA) of the lumbar medial branches has emerged as an effective, target-specific, minimally invasive treatment option, providing durable pain relief and improving functional outcomes in patients with chronic pain originating from lumbar Z-joints.6,7 The procedure is performed under fluoroscopic guidance and involves inserting percutaneous needles into the lumbar spine, with the needle tips subsequently resting over the respective medial branches. A microelectrode is inserted into the needle and delivers a radiofrequency current at 80°C for 60–90 seconds. This causes damage to the nerve tissue and interrupts its ability to transmit pain signals from the facet joints. The procedure has typically been performed to treat axial low back pain. However, there is limited information detailing the utility of this procedure to address concomitant lower extremity pain and paresthesias. Therefore, our case provides an example of when RFA may be an appropriate treatment option to address lower extremity pain secondary to lumbar spine pathology.
Illustrative Case
A female patient initially presented at age 62, after being referred by a total joint surgeon who was concerned about increasing pain (reported as 7 of 10 on the numeric pain rating scale) throughout the lower lumbar spine, radiating along the lateral aspect of the right lower extremity to the dorsum of the foot, with accompanying numbness and paresthesia of the anterior aspect of the right thigh. The patient had a past medical history consisting of hypertension and osteoarthritis and a past surgical history that included a total abdominal hysterectomy. She was being considered for right total knee arthroplasty, but the total joint surgeon wished to have her low back and radicular symptoms addressed before proceeding with joint replacement. Her symptoms had been present for approximately 1 year. She completed a 6-week course of physical therapy consisting of lumbar stabilization and passive modalities. She had also trialed medications over the prior year, including acetaminophen, nonsteroidal anti-inflammatory drugs, and gabapentin, with minimal relief. On examination, manual motor testing showed full strength throughout the lower extremities with no focal deficits. The sensation was intact to light touch throughout both lower extremities, and patellar and Achilles reflexes were normal and symmetric. Straight leg testing was negative bilaterally. Subsequent MRI of the lumbar spine confirmed L4–5 spondylosis with facet arthropathy and encroachment of the L5 nerve root. The patient was then scheduled for a right L4–5 and L5–S1 transforaminal epidural steroid injection.
Following the steroid injection, the patient indicated a 60% improvement in her symptoms, but within 3 weeks, her symptoms returned to baseline. By the following year, the patient presented with worsening pain with involvement of the left lower extremity as well. The patient inquired about the utility of medial branch radiofrequency lesioning for alleviating her symptoms. She was counseled that, while it could help with her axial low back pain, it was not typically indicated for treatment of lower extremity pain and paresthesias. She opted to proceed with treatment in the hopes of at least alleviating her axial complaints. She underwent 2 sequential diagnostic medial branch blocks performed using local anesthetic, resulting in an 80% improvement in symptoms and function and a decrease in pain with provocative maneuvers. Symptoms returned within 6 weeks of the procedure, but the results of the block indicated the patient was a candidate for radiofrequency lesioning of the medial branches.
Two years after her initial increase in symptom severity, the patient underwent fluoroscopically guided RFA of the bilateral L3, L4, and L5 medial branches. The procedure was performed following the standard radiofrequency thermoregulation technique. Two separate lesions were made at 80°C for 90 seconds at each level. The patient tolerated the procedure well, and there were no complications. Ten weeks following the procedure, the patient reported near-complete resolution of her back and lower extremity symptoms, with an approximate 80% overall improvement in symptoms; her right knee pain was to be addressed by her upcoming total knee replacement.
The patient experienced significant improvement in functional abilities and quality of life following the procedure and indicated that, should symptoms return, she would undergo the procedure again given its positive effects on her life.
Two years after her procedure, the patient indicated that none of her symptoms had returned.
Informed Consent
The necessary informed consent was obtained in this study.
Discussion
Observations
Lumbar medial branch RFA is a minimally invasive, target-specific procedure used to reduce or eliminate chronic back pain originating from the facet joints in the spine that has not responded to standard medication and therapy.8–10 It provides a minimally invasive alternative to more extensive surgical procedures, delivering durable pain relief with limited potential for complications. There is a paucity of literature describing the utility of RFA procedures to address lower extremity pain associated with lumbar spondylosis.11,12 Our case provides additional evidence to support the use of RFA to treat patients presenting with continued or worsening lower extremity pain and paresthesia in the face of known lumbar pathology.
Lessons
Medial branch RFA for lumbar spondylosis resulted in significant pain relief and functional improvement in this 64-year-old female patient with long-standing low back and lower extremity pain. Our case illustrates the potential benefits of medial branch RFA to treat ongoing lower extremity pain and paresthesias in patients whose symptoms are refractory to conservative measures. However, our case also presents evidence for the judicious use of diagnostic injections and careful observation prior to moving forward with an RFA procedure. There is a component of referred pain that emanates from the facet joints; therefore, one possible explanation for relief in this patient is an atypical referred pain pattern from these joints. Patients whose lower extremity symptoms persist following a course of physical therapy, analgesic medications, and epidural steroid injections will often undergo evaluation for possible surgical intervention. Consideration could be given to a trial of diagnostic medial branch blocks to assess for a facet-mediated source of their lower extremity symptoms. The medial branch blocks are very low-risk interventions that can provide this diagnostic information and determine if the patient is a candidate for RFA.
RFA of the lumbar medial branches is a very low-risk procedure when performed by an appropriately trained provider. Rare risks include significant bleeding, infection, and neurological injury. The more common risks include a temporary increase in pain, temporary numbness, and temporary dysesthesias of the skin overlying the injection sites. RFA should not be performed on patients who are significantly immunocompromised or are being treated for active infection. Caution should be taken when performing RFA near surgical hardware. Patients with cardiac pacemakers, bladder stimulators, and other implanted devices should receive clearance and coordination from their treating providers before RFA is implemented. The benefits of treatment include the relief of symptoms for an average of 6–12 months and sometimes several years. The medial branches can regenerate, at which time symptoms can recur. Patients can be considered for repeat RFA at a minimum of 6 months following their prior RFA treatment.
RFA of the medial branches has long been known to be a reasonable treatment pathway to explore in patients with axial low back pain, as a successful course of treatment can allow a patient to avoid surgical intervention. Our case highlights that it could also be considered in patients with refractory radicular symptoms.
Acknowledgments
We thank Mark Gleeson for his assistance with the literature review for this study.
Disclosures
The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.
Author Contributions
Conception and design: Codispoti. Acquisition of data: Solomito. Analysis and interpretation of data: Solomito. Drafting the article: both authors. Critically revising the article: both authors. Reviewed submitted version of manuscript: both authors. Approved the final version of the manuscript on behalf of both authors: Codispoti.
Correspondence
Vincent Codispoti: Orthopaedic Associates of Hartford, CT. vcodispoti@oahctmd.com.
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