Poster 390 Lumbar Radiculopathy Treated by Pulsed Radiofrequency Without Steroid: A Case Report

PM&R

Conclusions: The above described case provides an example of managing low back pain in a patient with dwarfism. The patient’s response to PT will provide information to help guide management of low back pain in other dwarfism patients. Poster 387 A Ventral Epidural Facet Cyst Causing Central Canal Stenosis and Lumbar Nerve Compression in a Woman With Radicular Type Low Back Pain: A Case Report. Mark Miedema (University of Colorado, Denver, CO, United States); Scott Laker, MD. Disclosures: M. Miedema, No Disclosures. Case Description: The patient presented with 6 weeks of gradual onset, constant sharp low back pain radiating into both legs without inciting trauma. Her symptoms worsened with weight bearing and were relieved with sitting. History was otherwise unremarkable and her examination was notable for positive dural tension signs. Radiograph of the lumbar spine revealed facet arthropathy at L5-S1. Initial lumbar MRI without contrast was obtained and showed severe L4-5 facet arthrosis, a high T2-weighted, multilocular lesion in the ventral epidural space at L4-5 creating moderate to severe central spinal canal narrowing and right L5 nerve compression within the right lateral recess. Subsequently, an MRI with contrast was obtained which again demonstrated the anterior epidural multilocular cystic mass with linear enhancement and confirmed the suspicion of a dissecting synovial cyst arising from the adjacent right L4-5 facet, and ruling out neoplasm. She was treated with a CT-guided rupture of the facet cyst and right L4-5 transforaminal epidural steroid injection. Setting: Outpatient spine rehabilitation clinic. Results or Clinical Course: At 3 weeks after facet cyst rupture the patient had significant improvement in her pain. Discussion: This is the first reported case, to our knowledge, of a ventral epidural multilocular lesion arising from a dissecting synovial cyst. Conclusions: Although uncommon, dissecting synovial cysts should be considered in the differential diagnosis of ventral epidural lesions in the setting of known facet arthropathy. Poster 388 Hyperalgesia in Chronic Nonspecific Low Back Pain: Does it Matter? Marta Imamura, MD, PhD (Clinical Research CenterInstitute of Physical Medicine and Rehabilitation, University of São Paulo School of Medicine, São Paulo, Brazil); Fabio Alfieri, PhD; Linamara R. Battistella, PhD; Paula D. Delfino, BcA; Thais R. Filippo; Talita J. Santos, BcA. Disclosures: M. Imamura, No Disclosures. Objective: To determine the relation of main demographic variables and pressure pain threshold (PPT) measures of several anatomical structures to pain and function scales in patients with chronic nonspecific low back pain. Design: Cross-sectional study. Pressure pain threshold (PPT) were measured bilaterally during the pinch and roll maneuver at L1, L2, L3, L4, L5, S1, and S2 dermatomes and over the gluteus medius, gluteus minimus, gluteus maximus, piriformis, quadrates lumborum and iliopsoas muscles. Unilateral PPT measures were per-

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formed over the L1-L2, L2-L3, L3-L4, L4-L5 supraspinous ligaments. Lumbar pain intensity was assessed by VAS. Lumbar function was evaluated using the Roland Morris questionnaire. Multiple linear regression models with stepwise selection determined the association for both VAS and RM using demographic data and PPT values. Setting: Clinical Research Center - Institute of Physical Medicine and Rehabilitation, University of São Paulo School of Medicine. Participants: We assessed 124 patients, females (56%), Caucasians (54%), with mean age of 50.10⫾7.95 years, median duration of pain of 96.00 months (range 6-360), mean body mass index (BMI) of 27.3⫾4.97. The main education level was elementary (53.2%), high school (39.5), university (4.0%), illiterate (3.2%). Results: Mean PPT values were similar on both sides (P⬎.05). Mean VAS value was 7.31⫾1.53. Mean RM score was 14.23⫾5.27. Lower PPT values were observed at the L1 dermatomal level and higher at the gluteus minimus muscle. PPT values showed statistically significant correlations inversely proportional to VAS (P⬍.001) and RM (P⬍.001). Highest correlation with VAS was the PPT value at the gluteus medius muscle (r⫽⫺0.336), which was the only measure that influenced pain intensity (r2⫽0.11). RM was influenced by BMI, educational level, PPT values at the iliopsoas muscle and L4-L5 supraspinous ligament (r2⫽0.32). Conclusions: Most PPT values correlate to VAS and RM. However, the variability explained by PPT values and demographic characteristics was low for pain and function. Therefore, other characteristics should be investigated. Poster 390 Lumbar Radiculopathy Treated by Pulsed Radiofrequency Without Steroid: A Case Report. Michael W. Wolff, MD (Southwest Spine and Sports, Scottsdale, AZ, United States); Hisashi W. Kobayashi, MD. Disclosures: M. W. Wolff, No Disclosures. Case Description: Patient underwent pulsed radiofrequency (PRF) treatment of dorsal root ganglia at right L4-5 and L5-S1 levels, without steroid administration. Under fluoroscopy, a radiofrequency ablation needle was guided towards neuroforamen. The needle location was adjusted until the patient reported brief paresthesia in the expected dermatome. Sensory stimulation testing reproduced radicular paresthesia at 0.29 and 0.31 volts at L4-5 and L5-S1 levels, respectively. After administering 1% lidocaine locally, PRF was carried out at 42 degrees Celsius for 2 minutes at each level. Program Description: A 66- year-old woman with 6-month duration of right lower extremity pain radiating through anterolateral thigh and posterolateral calf to foot dorsum. Magnetic resonance imaging was notable for moderate right L4-5 and L5-S1 neuroforaminal stenoses associated with adjacent disc protrusions and zygapophyseal joint arthrosis. She initially underwent right L4-5, L5-S1 transforaminal epidural steroid injection (ESI) with betamethasone. She was treated prophylactically with diphenhydramine before ESI, due to history of adverse effects from a prior elbow steroid injection. Two weeks after ESI, she reported 100% worsening of her pain. Setting: Ambulatory surgery center. Results or Clinical Course: Patient reported 60% reduction of pain at 8 weeks, and sustained pain relief at 12 weeks, following PRF. No adverse effects from the procedure were reported.

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Discussion: PRF remains an underutilized interventional treatment for lumbar radiculopathy. When it is used, to our knowledge, most practitioners combine it with steroid administration to the nerve root for additive therapeutic effect. This case illustrates the potential utility of steroid-free PRF for patients who are unable to tolerate steroid side effects. PRF’s mechanism of action is still unclear. Theories include electromagnetic field alteration of celluluar protein expression and heat-induced modulation of neural transmission that selectively affects pain fibers. Conclusions: PRF may be an alternative to ESI for patients with lumbar radiculopathy who are unable to tolerate steroids. Poster 391 Steroid Psychosis After Cervical Transforaminal Epidural Steroid Injection: A Case Report and Literature Review. Michelle D. Francavilla, (University of Miami Miller School of Medicine, Miami, FL, United States); Jose Mena, MD. Disclosures: M. D. Francavilla, No Disclosures. Case Description: The patient is a 59-year-old woman with a history of chronic neck pain radiating to the right shoulder. She was diagnosed with right-sided C5 radiculitis resulting from right-sided disk osteophyte complexes and foraminal narrowing. She underwent a right C4-C5 cervical transforaminal steroid injection with 10 mg of dexamethasone. At subsequent follow-up visits the patient reported a feeling of “cloudiness” for a total of 5 weeks after the injection. She also reported feeling that her cognition was altered and that she felt she was less rational about her level of pain. After the 5-week time period her mental status returned to her baseline and she felt as though her psychiatric symptoms had completely resolved. Setting: Tertiary academic medical center outpatient rehabilitation clinic. Results or Clinical Course: The patient is believed to have been experiencing steroid psychosis resulting from the cervical epidural steroid injection that was done prior to her becoming symptomatic. She had no other medication changes during that time period and no other medical source to account for her transient psychiatric symptoms. Discussion: This is the first reported case, to our knowledge, of steroid psychosis resulting from an epidural steroid injection. A literature review revealed only 3 cases total of psychosis resulting from a steroid injection of any kind, which in all other instances were from intra-articular injections. Conclusions: Steroid psychosis is a rare but possible side effect from neuroaxial procedures including epidural steroid injections and should be considered as a potential source of psychosis in the appropriate setting. Poster 392 Physical Activity Intensity Signatures (PAIS) of Pain: Large-Scale Study Reveals Novel Cut-Points for Accelerometry Analysis in Regional Body Pain. Ming-Chih J. Kao, PhD, MD (Stanford University, Palo Alto, CA, United States); Renata Jarosz, DO; Sean Mackey, MD, PhD; Matthew Smuck, MD; Christy Tomkins-Lane, PhD. Disclosures: M. J. Kao, No Disclosures. Objective: To discover signature patterns of physical activity

PRESENTATIONS

intensity alterations due to regional body pain, and to empirically derive physical activity intensity signatures cut-points (PAIS cutpoints) for accelerometry studies of pain. Design: Cross-sectional population-based survey. Setting: University-based PM&R program. Participants: 6,796 subjects from NHANES (2003-2004). Interventions: Functions and programs in Python 2.7 and R 2.11, procedures and macros in SAS 9.2 were written and employed for data processing, complex survey regression analyses, model selection, and clustering. Main Outcome Measures: Physical activity intensity profiles per subject are adjusted for demographic, social, and medical variables as previously described. Self-reported pain in various body regions are summarized. Two-way hierarchical clustering was performed. Across body regions, there is close clustering of axial pain (headache/migraine, neck, upper back, and lower back), in contrast to appendageal pain (shoulder, arm, hand, leg, and foot). Across intensity intervals, there is coherent and tight clustering of counts per-minute intervals within certain ranges, which are adopted to define PAIS cut-points. More extreme intensities in the low end (zero) and high end (⬎30,000) are not considered given high coefficients of variation. Results: “PAIS cut-points” are empirically derived that define novel “PAIS intervals” that can be seen as an elaboration of existing intervals for sedentary activity: 1-190 (“PSE”); light activity: 191350 (“PL1”), 351-800 (“PL2”), and 801-2,500 (“PL3”); and moderate/intense activities: 2,000-30,000 (“PMI”). Across these five intervals, distinct signatures of activity alterations are seen for axial pain and appendageal pain. Conclusions: Applying statistical and machine learning techniques to a population-based biomechanical assessment of freeliving physical activity, we derived novel intervals (“PAIS intervals”) for accelerometry analysis specially tuned to detect signature patterns of alterations in physical activity intensities due to regional body pain. Compared to existing cut-points based on cardiovascular considerations, these cut-points are distinct in motivation, empiric in origin, and provide finer resolution in the light activity ranges. These features may enable more productive investigations of accelerometry in pain. Poster 393 Population Reference Chart for Accelerometry: The Pain-Free Physical Activity Reference Chart (PARC). Ming-Chih J. Kao, PhD, MD (Stanford University Medical Center, Palo Alto, CA, United States); Michael J. Burns, MD; Sean Mackey, MD, PhD; Matthew Smuck, MD; Christy Tomkins-Lane, PhD. Disclosures: M. J. Kao, No Disclosures. Objective: To construct population-level reference charts for pain-free physical activity. Design: Cross-sectional population-based survey. Setting: Population-based survey. Participants: 6,796 subjects from NHANES (2003-2004). Interventions: All subjects completed a 7-day free-living assessment of physical activity by accelerometry and provided extensive sociodemographic and health-related information. Functions and programs in Python 2.7 and R 2.11, procedures and macros in SAS 9.2 were written and employed for semi-automated data processing, complex survey analyses, model selection, cut-point selection, quantile regression with splines, and visualization.