Dexamethasone Effectively Reduces the Incidence of Post-neurotomy Neuropathic Pain: A Randomized Controlled Pilot Study.

BACKGROUND: Radiofrequency neurotomy (RFN) of facet or sacroiliac joints is widely used for the treatment of chronic axial pain and can provide long-term pain relief in well-selected patients. The most common side effect is transient neuropathic pain at the paravertebral level of interest. Pain physicians commonly administer corticosteroid post-neurotomy to reduce the risk of post-neurotomy neuropathic pain, yet it remains unclear if this provides a true reduction in incidence. OBJECTIVES: To determine the efficacy of corticosteroid administration post-lesion in preventing the development of post-neurotomy neuropathic pain after cervical, thoracic, lumbar, and sacroiliac joint radiofrequency denervation. STUDY DESIGN: Randomized, placebo-controlled, double-blind prospective study. SETTING: Ambulatory Surgical Center within a Tertiary Hospital System. METHODS: This trial is registered on ClinicalTrials.gov (NCT03247413). Permission to conduct human research was obtained from the Institutional Review Board. Eligible patients included those with cervical, thoracic, or lumbar facet or sacroiliac joint pain who had positive concordant medial branch blocks (thus scheduled for bilateral RFN), at least 18 years of age, and English-speaking. Patients received dexamethasone vs saline (control) at each lesion site, serving as their own control (with laterality). Follow-ups were completed at 4- and 8-weeks post-intervention to evaluate the incidence of post-procedure pain (questionnaire) and function using the Oswestry Disability Index (ODI) or the Neck Disability Index (NDI). RESULTS: At the time of data analysis, 35/63 patients completed the study protocol. There was a statistically significant reduction in the incidence of post-neurotomy pain in the steroid group vs the control group (20/35 control group vs 3/35 steroid group, P < 0.001). ODI/NDI scores changed differently over time depending on the spinal level of neurotomy, showing statistically significant improvement in ODI/NDI in the cervical subgroup and lumbar subgroup at 4-week (P = 0.05) and 8-week time points (P < 0.01), respectively. There was no improvement of ODI scores in the sacral subgroup. The incidence of post-neurotomy neuropathic pain was not significantly different among patients with different spinal levels of neurotomy. Patients who developed post-neurotomy neuropathic pain did not differ in ODI/NDI scores at any time point. LIMITATIONS: This study has several limitations, most notably the number of patients lost to follow-up, the use of a single corticosteroid, and the use of laterality for incidence reporting. Additionally, all procedures were performed by a single interventionalist using one neurotomy system. CONCLUSIONS: A statistically significant reduction in post-neurotomy pain was observed in the steroid group. This protocol can be feasibly conducted in an effective and resource-efficient manner. Additional research is needed to increase the power of the study.

Tolerability and Feasibility of X-ray Guided Non-Invasive Ablation of the Medial Branch Nerve with Focused Ultrasound: Preliminary Proof of Concept in a Pre-clinical Model.

Four to six million patients a year in the United States suffer from chronic pain caused by facet joint degeneration. Thermal ablation of the affected facet joint's sensory nerve using radiofrequency electrodes is the therapeutic standard of care. High-intensity focused ultrasound (HIFU) is a novel technology enabling image-guided non-invasive thermal ablation of tissue. Six pigs underwent fluoroscopy-guided HIFU of the medial branch nerve and were followed up for 1 wk (two pigs), 1 mo (two pigs) and 3 mo (two pigs). At the end of each follow-up period, the animals were sacrificed, and targeted tissue was excised and evaluated with computed tomography scans as well as by macro- and micropathology. No significant adverse events were recorded during the procedure or follow-up period. All targets were successfully ablated. X-Ray-guided HIFU is a feasible and promising alternative to radiofrequency ablation of the lumbar facet joint sensory nerve.

The utility of radionucleotide imaging in the surgical management of axial neck pain from cervical facet joint arthropathy.

OBJECTIVE: Axial neck pain is common and often debilitating. Diagnosis of the specific pain source can be a challenge, and this confounds effective treatment. Cervical facet arthropathy is implicated in many of these cases. The diagnosis is readily made on conventional cross-sectional imaging modalities, particularly CT imaging. However, this modality falls short in determining if an osteoarthritic facet joint is truly the source of symptoms. Radionucleotide imaging presents a noninvasive radiological adjunct to conventional cross-sectional imaging in the workup of patients with suspected facetogenic pain. Herein, the authors present the patient-reported outcomes (PROs) following posterior instrumented arthrodesis of the subaxial cervical spine from a consecutive case series of patients with a diagnosis of cervical facet joint arthropathy and a concordant positive radionucleotide tracer uptake. METHODS: The clinical case series of patients treated by the senior author at a single tertiary care institution between September 2014 and April 2018 was reviewed. Patients were selected for inclusion if their primary symptom at presentation was axial neck pain without neurological deficits and if CT imaging revealed facet arthropathy of the cervical spine. These patients underwent radionucleotide imaging in the form of a planar 99mTc methylene diphosphonate (99mTc MDP) bone scintigraphy study. Those with a finding of radionucleotide tracer uptake at a location concordant with the facet arthropathy were selected to undergo posterior cervical instrumented arthrodesis of the affected levels. PROs were recorded at the time of surgical consultation (i.e., after nonoperative treatment) and at 6 weeks, 3 months, 6 months, and 1 year following surgery. These included neck and arm pain, the Neck Disability Index (NDI) and the 12-Item Short Form Health Survey responses. RESULTS: A total of 11 patients were included in this retrospective case series. The average reported neck pain and NDI scores were high at baseline; 7.6 ± 2.3 and 37.1 ± 13.9 respectively. Twelve months after surgical intervention, a significant decrease in reported neck pain of -4.5 (95% CI -6.9, -2.1; p = 0.015) and a significant decrease in NDI of -20.0 (95% CI -29.4, -10.6; p = 0.014) was observed. CONCLUSIONS: This case series represents the largest to date of patients undergoing surgical arthrodesis following a finding of facet arthropathy with a concordant positive radioisotope image study. These observations add support to a growing body of evidence that suggests the utility of radioisotope imaging for identification of a facetogenic pain generator in patients with primary axial neck pain and a finding of cervical facet arthropathy. These preliminary data should serve to promote future prospective, controlled studies on the incorporation of radionucleotide imaging into the workup of patients with suspected facetogenic pain of the cervical spine.