Genicular Nerve Anatomy and Its Implication for New Procedural Approaches for Knee Joint Denervation: A Cadaveric Study.

OBJECTIVE: To verify the articular branch contributions in the human knee, delineate their anatomical variance, and outline the limitations of currently applied procedure protocols for denervation of the knee joint. DESIGN: A detailed anatomical dissection. SETTING: Cadavers in residence at the Albert Einstein College of Medicine. SUBJECTS: In total, 24 lower extremity specimens from 14 embalmed cadavers. METHODS: Human cadaveric dissections were performed on 24 lower extremities from 14 embalmed cadavers. RESULTS: This cadaveric study has demonstrated that the anterior knee receives sensory innervations from SMGN, SLGN, LRN, NVI, NVL, RFN, and IMGN. The courses of SMGN, SLGN, RFN, and IMGN are similar to recent anatomical studies. However, discrepancies exist in their relative anatomy to bony and radiographic landmarks. CONCLUSIONS: Genicular denervation using classical anatomical landmarks may not be sufficient to treat the anterior knee joint pain. Our findings illustrate more accurate anatomic landmarks for the three-target paradigm and support additional targets for more complete genicular denervation. This cadaveric study provides robust anatomical findings that can provide a foundation for new anatomical landmarks and targets to improve genicular denervation outcomes.

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.