(466) The impact of body mass index on fluoroscopy time during lumbar epidural steroid injection: a multicenter cohort study

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Abstracts

The Journal of Pain

injectate. While contrast is injected to ensure appropriate epidural spread, we present, to the best of our knowledge, the first occasion of a needle being inserted directly into the filum terminale during a caudal ESI.

F23 Other Interventional Techniques (464) Prior voluntary wheel running is protective for neuropathic-like pain P Grace, K Strand, E Galer, N Anderson, T Fabisiak, S Fulgham, B Greenwood, M Fleshner, S Maier, and L Watkins; Department of

(462) The effectiveness of cervical facets infiltration of C2-3 in the treatment of transformed migraine (TM) plus cervicogenic component Z Elchami, A Mirambel, E Umlas, R Massoud, S Delos Santos, and A Villamar; International Medical Center, Jeddah, Saudi Arabia Transformed migraine (TM) is a chronic, daily headache, with vascular quality. Patients usually use large doses of analgesics and experience withdrawal headaches. Cervicogenic migraine, on the other hand, is a secondary headache due to an underlying structural problem in the head or neck. The objective of this study is to evaluate the effectiveness of cervical facets infiltration of C2-3 in the treatment of transformed migraine (TM) plus cervicogenic component. 30 patients were evaluated at the Pain & Headache Center, IMC, KSA, according to IHS classification. Patients were allocated to receive either cervical infiltration of C2-# facets on the same side of migraine (13); or oral bridge therapy (Eletriptan and Etoricoxib) which was administered daily for 15 days, and which was followed by Topiramate 100mg daily for 6 months as a preventive therapy in both groups. Inclusive criteria: 10 males, 20 females; ages 30-50 years, with a mean of 40. Exclusive criteria: pediatrics; patients older than 50, with uncontrolled diabetes, blood pressure, other neurological deficits; or pregnancy. Average symptomatic improvement of 78%, according to numeric pain scale, was recognized in patients receiving cervical facets infiltration therapy and appreciated within 10-20 days of therapy. However, an average improvement of 58% was recognized by patients receiving oral bridge therapy and appreciated within one month of therapy. Patients who received cervical facets infiltration showed more rapid and significant symptomatic improvement of their headache after the treatment as compared to the oral bridge therapy.

Psychology and Neuroscience, The Center for Neuroscience, University of Colorado, Boulder, CO

Exercise is posited to alleviate the symptoms of chronic pain in both rodent models and in patients. However, there has been no investigation of the effects of prior exercise on subsequent neuropathic pain. In this study, we addressed this gap by determining whether 6 weeks of voluntary wheel running prior to chronic constriction injury (CCI) of the sciatic nerve would attenuate subsequent allodynia and inflammatory processes in adult male rats. Access to the running wheels ended upon sham vs. CCI surgery. Allodynia was significantly attenuated for rats given unrestricted access to running wheels prior to CCI, relative to controls housed with a locked wheel. The protection persisted for the 14-week duration of the injury. Withdrawal thresholds after sham surgery were not significantly altered following unrestricted access to running wheels, relative to controls housed with a locked wheel. The attenuated allodynia in CCI rats was associated with decreased inflammatory marker expression at two weeks after CCI. Specifically, expression of P2X4R, phospho-p38 MAPK, phospho-p65 of NFkB, and BDNF was attenuated in the spinal L4-L5 dorsal quadrants. Markers for macrophage infiltration, Iba1 and CCL2, were decreased in the injured sciatic nerve. Notably, both iNOS (M1 macrophage marker) and Arg1 (M2 macrophage marker) were decreased in the injured sciatic nerve, which suggests that protection may not be associated with alternative activation, but simply suppression of inflammatory signaling. These novel data demonstrate that regular voluntary running confers resilience to chronic pain subsequent to nerve injury. This is likely mediated by suppressed inflammatory signaling, as these processes are pro-nociceptive.

(465) Exercise-induced hypoalgesia following six minute walk test

F21 Sympathetic Blocks

A Alsouhibani, E Hrdina, R Krajewski, A Chirayil, S Stolzman, and M Hoeger Bement; Marquette University, Milwaukee, WI

(463) Dual imaging technique for stellate ganglion blockade

High intensity aerobic exercise has been shown to decrease pain perception in healthy participants, a phenomenon known as exercise induced hypoalgesia (EIH). Little is known regarding the effect of low intensity aerobic exercise, a level of exercise commonly prescribed in clinical populations. This study tested EIH following a clinically relevant functional test (six minute walk test) that is of low aerobic intensity and duration. Twenty young healthy adults (2163.2 years; 10 males) completed the six minute walk test, temporal summation (TS) protocol, and conditioned pain modulation (CPM) protocol. Pressure pain thresholds (PPTs) were measured pre and post exercise at the quadriceps muscle, deltoid muscle, and nailbed. TS was measured via a constant pressure (1.5 Kg) on the right index finger for 2 minutes with pain ratings reported every 20 seconds. CPM was assessed by measuring PPTs at the quadriceps muscle, deltoid muscle, and tibia while the foot was submerged in a cool water bath (25 C) and then 20 minutes later in an ice water bath (0 C). PPTs increased after the six minute walk test similarly between men and women (trial x sex; p>0.05) which was site specific (trial x site; p<0.05). Post-hoc analysis show that PPTs increased only at the quadriceps site, and not the deltoid muscle or nailbed, following the six minute walk (p<0.05). EIH was not related to TS or CPM in these individuals. In general, the six minute walk test, which is frequently used to assess physical fitness, results in hypoalgesia at the localized muscle but not systemically. Clinically, the assessment of physical fitness using a six-minute walk test may influence pain assessments.

J Shepherd, A Dua, and D Martin; Medical College of Georgia, Augusta, GA A 47-year-old male with a 4-year history of complex regional pain syndrome of the right upper extremity, the result of a motor vehicle accident, presented for stellate ganglion diagnostic/therapeutic blockade. Fluoroscopic imaging and ultrasound guidance were used to place the needle at the anterior base of the uncinate process of C7, and anterolateral to the longus colli muscle. After negative aspiration, 2 mL of contrast was then injected under fluoroscopy to identify any inadvertent intravascular injection. 4 mL of 2% lidocaine was then injected and the needle was withdrawn. The patient experienced Horner’s syndrome and an increased skin temperature of the right upper extremity. Stellate ganglion blocks provide a valuable diagnostic and therapeutic benefit to sympathetically mediated pain syndromes in the head, neck, and upper extremity. First described in the1920s, the standard ‘‘blind’’ technique was eventually replaced with fluoroscopically guided techniques. Over the past few years, there has been a growing interest in the ultrasound-guided technique and the perceived advantages that it might offer. Ultrasound guidance offers the obvious advantage of direct visualization of vascular structures (inferior thyroidal, cervical, vertebral, and carotid arteries) and soft tissue structures (thyroid, esophagus, and nerve roots). Although ultrasound is associated with significant advantages, it does have limitations. Visualization of certain structures including bone and deeper tissues can be limited. Bone has a high attenuation coefficient and casts an acoustic shadow; thus, structures hidden by bone are not well visualized. Due to the learning curve associated with ultrasound guided blocks many practitioners are hesitant to adopt it into their daily practice. Fluoroscopy, on the other hand, is a reliable method for identifying bony surfaces, which facilitates identifying the C7 uncinate process. A combined imaging approach allows practitioners learning ultrasound the familiarity of fluoroscopy, while providing added safety via imaging of vascular and soft tissue structures.

(466) The impact of body mass index on fluoroscopy time during lumbar epidural steroid injection: a multicenter cohort study S Choxi, Z McCormick, D Cushman, D Walega, D Lee, A Marcolina, J Press, D Kennedy, and M Smuck; Northwestern University, Chicago, IL Though a range of interventional and surgical procedures have been associated with longer fluoroscopy times and greater

Abstracts

The Journal of Pain

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radiation exposure with increasing body mass index (BMI), few studies have analyzed this relationship during spine injections for pain management. The present study aimed to define the relationship between BMI and fluoroscopy time during lumbar epidural steroid injection (LESI) performed for lumbosacral radicular pain. This was a multicenter retrospective cohort study conducted at three academic, outpatient pain treatment centers. Mean and standard deviation (SD) fluoroscopy times were calculated, and comparisons were made between patients with normal (18.5 24.9 kg/m2), overweight (25.0 - 29.9 kg/m2), and obese ($30.0 kg/ m2) BMI. This cohort included a total of 2,930 patients, 598 who received interlaminar LESIs and 2,332 who received transforaminal ESIs. There was a significant difference in the mean fluoroscopy time for both interlaminar and transforaminal LESI between these BMI classes, with obese patients requiring longer fluoroscopy times (p<0.01; p<0.01). This relationship was also observed when a trainee was involved with the procedure (p<0.01) and during bilateral transforaminal LESIs (p<0.01). While longer fluoroscopy times were required in obese patients during L5-S1 transforaminal LESI (p<0.01), there was no relationship between fluoroscopy time and BMI during L4-L5 and S1 transforaminal LESI (p=0.02; p=0.13). Future study is needed to determine the relationship between BMI and radiation exposure dose in order to determine if these observed differences in fluoroscopy time change the risk of developing a malignancy.

formed resulting in complete resolution of pain. Patient one week later underwent cryoablation of the neuroma under ultrasound guidance. He subsequently has excellent pain relief resulting in him being able to utilize his prosthesis for the first time in over 9 years. Patient is now able to ambulate pain free in the community with one lofstrand crutch. Chronic pain is reported in up to 95% of patients with amputations. Persistent pain in amputees can be the result of many etiologies including the formation of a neuroma. Neuromas can develop at the site of transection of any peripheral nerve. While the pain from a neuroma is usually well localized to the injury site it has also been implicated in phantom limb pain. An ultrasound guided diagnostic nerve block with local anesthetic can help support the diagnosis. Treatment of pain stemming from neuromas may persist despite conservative management and may require interventional procedures including ultrasound guided cryoablation. Directing focal extreme cold temperatures at the neuroma after proper visualization under ultrasound results in demyelinazation and Wallerian degeneration resulting in significant pain relief by blocking nerve transmission. This case represents an excellent outcome of a previously debilitating stump neuroma after ultrasound guided cryoablationtherapy. The interventional procedure allowed improved functionality, complete pain relief and the ability to ambulate with more independence for the first time since a traumatic hip disarticulation over 35 years ago.

(467) The use and perceived efficacy of dental and non-dental treatments by TMD patients with and without fibromyalgia

(469) Optimizing chronic pain treatment with enhanced neuroplastic responsiveness

V Santiago and K Raphael; New York University College of Dentistry, New

K Sibille, A Keil, A Woods, R Staud, and R Fillingim; University of Florida,

York City, NY

Gainesville, FL

Temporomandibular muscle and joint disorder (TMD) is highly comorbid with fibromyalgia (FM). Although primarily treated by dentists, it is unclear whether TMD patients with comorbid FM receive different treatments or have differential response compared with TMD-only patients. This study compares types and efficacy of self-reported TMD treatments in TMD patients, with and without comorbid FM. Subjects were recruited from university dental clinics. TMD and FM were assessed via clinical research examinations. Treatment histories and self-reported treatment efficacy were obtained via interview. A total of 125 TMD positive women were enrolled. Of these, 26 were assessed FM+ and 98 were FM-. Analyses include results on 9 specific treatments queried (oral appliances, physical therapy, jaw exercises at home, acupuncture, chiropractic manipulation, trigger point injection, electrical stimulation (TENS), biofeedback and surgery). The mean number of treatments ever used did not differ by FM status (2.1 treatments (SD=1.4)). The top 3 most common treatments reported were oral appliances (59%), physical therapy (54%) and jaw exercises at home (34%). Frequency of ever using each treatment did not differ by FM status. Further grouping of treatments identified increased use of alternative treatments (i.e. chiropractic manipulation and acupuncture) by FM+ subjects (46% vs 27%, pvalue=.05). Mean patient satisfaction by category did not differ significantly by FM status for dental or alternative treatments, but a trend (p=.08) toward increased helpfulness of physical therapy was found in the FM+ vs FM- physical therapy users. Results from this sample of facial pain patients with TMD suggest that subjects who also meet FM diagnostic assessment may be more likely to report potential greater efficacy of physical therapy than TMD only subjects. Although alternative treatments were nearly twice as frequent among FM positive subjects, self-reported efficacy was not significantly different. This work was supported in part by NIH grants R01DE018569 and R01DE024522-01S1.

Chronic pain drives adverse changes in brain regions involved in affective and somatosensory processing. Although new learning has been demonstrated in adulthood, more recent advances indicate promising opportunities to ‘‘re-open’’ and enhance neuroplastic responsiveness and training benefits in adults with non-invasive interventions, such as food restriction and glucose administration. Strategies to maximize neuroplastic responsiveness to chronic pain treatment could enhance treatment gains by accelerating neurogenesis and increasing learning and positive central nervous system (CNS) adaptation. The intent of the investigation is to identify interventions that will optimize the neurobiological environment to respond to treatment and override the maladaptive neuroplastic changes associated with chronic pain. Guided imagery is an effective clinical intervention for chronic pain and serves as the therapeutic modality in this study. The overall aims are to 1) determine whether food restriction and/or glucose administration will enhance neuroplastic responsiveness and improve the effectiveness of a guided imagery intervention in chronic pain patients; and 2) to identify neurobiological mechanisms underlying the proposed interventions in adults who have chronic pain associated with osteoarthritis. Sixty adults with chronic osteoarthritis pain are randomized to one of three groups: food restriction, glucose administration, or control. The three groups participate in four sessions of a structured guided imagery intervention over a four-week period. Blood samples are collected to measure plasma glucose. Sessions 1 and 4 include EEG, clinical and experimental pain, affect, distress, and memory measures. The long-term goals of this developing line of research are to identify and apply effective strategies that will enhance neuroplastic responsiveness and learning in the treatment of chronic pain. There is tremendous potential clinical relevance from the proposed interventions which are non-invasive, feasible and inexpensive to administer, implementable in numerous setting including programs targeting underprivileged populations, and may be applicable across a continuum of chronic pain treatments.

(468) Cryoablation of a hip disarticulation residual limb neuroma allowing for ambulation and pain relief: a case report R Ramsook and D Spinner; Icahn School of Medicine at Mount Sinai, New York, NY

A 57-year old man with a past medical history of right hip disarticulation in 1978 presented with excruciating right residual limb pain for over 10 years. The knife-life 10/10 phantom pain and allodynia had prevented him from using his prosthesis, resulting in him having to utilize bilateral crutches and a wheelchair for mobility. Ultrasound examination revealed right stump neuroma for which an ultrasound guided diagnostic nerve block was per-

(470) Effects of lidocaine injections on overall fatigue in patients with chronic fatigue syndrome R Staud, J Boissoneault, D Price, and M Robinson; University of Florida, Gainesville, FL

Chronic fatigue is prevalent in the general population with can significantly impact patients’ quality of life and function. It not only common in patients with cancer, chronic infections, and autoimmune diseases, but also in individuals with depression, insomnia