Bipolar Radiofrequency Lesion Geometry: Implications for Palisade Treatment of Sacroiliac Joint Pain

Ex vivo photographic temperature mapping of bipolar radiofrequency (RF) lesions in animal tissue is performed over a wide range of electrode tip spacings, tip lengths, tip diameters, tip temperatures, and lesion times. In vivo temperature measurements collected during clinical treatment of sacroiliac joint (SIJ) pain corroborate those collected ex vivo. Generation of a “strip lesion” connecting two separated bipolar electrode tips is demonstrated ex vivo for tip spacings as large as 20 mm. A rounded rectangular bipolar lesion with midline dimensions 12 mm × 15 mm × 8 mm (L × W × D) is demonstrated using 10 mm parallel tip spacing, 10 mm tip lengths, 20 gauge cannulae, 90°C tip temperature, and 3‐minute lesion time. Lesion length can be increased to 18 mm by using 15 mm tip lengths. Lesion width can be increased to 17 mm by using 12 mm tip spacing. The size of conventional bipolar lesions can exceed the size of lesions produced both by conventional monopolar RF (12 mm × 7 mm × 7 mm ellipsoidal) and by cooled monopolar RF as used in spinal pain management (10 mm × 10 mm × 10 mm spherical). SIJ pain is treated by placing 5 to 7 straight RF cannulae perpendicular to the dorsal sacrum and producing 4 to 6 overlapping bipolar RF lesions between the dorsal sacral foramina and the ipsilateral SIJ. This bipolar “palisade” (a defensive fence) creates a continuous lesion spanning the region through which multiple sacral lateral branch nerves travel along irregular, branching paths to reach the SIJ.     

17. Herpes Zoster and Post‐Herpetic Neuralgia

Herpes zoster infection is caused by a reactivation of the latent varicella zoster virus that causes chicken pox. It appears predominantly in older adults whose immunity for the virus has waned. The natural course of the disease is usually favorable, and the symptoms disappear spontaneously within a few weeks. Some patients, however, have prolonged pain: post‐herpetic neuralgia. The diagnosis of acute zoster infection is made on the clinical signs including the appearance of rash. Post‐herpetic neuralgia is described as sharp, burning, aching, or shooting constantly present in the dermatome that corresponds with the earlier rash. The objectives of treating herpes zoster are: (1) acute pain reduction; (2) promotion of recovery of epidermal defects and prevention of secondary infections; and (3) reduction or prevention of post‐herpetic neuralgia. The objective of the treatment of post‐herpetic neuralgia is primarily pain alleviation and improvement of the quality of life. Early treatment of the infection and the pain is believed to reduce the risk for post‐herpetic neuralgia. This persistent pain syndrome is difficult to treat. Antiepileptic drugs and tricyclic antidepressants are the first choice. Interventional treatments, such as epidural injections of corticosteroids and local anesthetic drugs, have an effect on the acute pain but are of limited use in preventing post‐herpetic neuralgia. When conservative treatment fails in providing satisfactory relief of post‐herpetic neuralgia, a sympathetic block may be considered (2 C+); if this treatment provides unsatisfactory results, spinal cord stimulation may be considered, in a study context (2 C+). ?     

Sphenopalatine Ganglion Pulsed Radiofrequency Treatment in 30 Patients Suffering from Chronic Face and Head Pain

Abstract:   This study evaluated the efficacy of sphenopalatine ganglion pulsed radiofrequency (SPG-PRF) treatment in patients suffering from chronic head and face pain. Thirty patients were observed from 4 to 52 months after PRF treatment. The primary efficacy measures were the reduction in oral medication use, including opioids, time-to-next-treatment modality for presenting symptoms, duration of pain relief, and the presence of residual symptoms. Secondary objectives included the evaluation of adverse effects and complications. All data were derived from patient charts, phone conversations, and clinical follow-up visits. Fourteen percent of respondents reported no pain relief, 21% had complete pain relief, and 65% of the patients reported mild to moderate pain relief from SPG-PRF treatment. Sixty-five percent of the respondents reported mild to moderate reduction in oral opioids. None of the patients developed significant infection, bleeding, hematoma formation, dysesthesia, or numbness of palate, maxilla, or posterior pharynx. A large-scale study of SPG-PRF for the treatment of face and head pain has not been previously reported. Our results suggest that a prospective, randomized, controlled trial study to confirm efficacy and safety of this novel treatment for chronic head and face pain is justified.     

Incidental Diagnosis of Intradural Lumbar Disc Herniation During Discography: A Case Report

▪ Abstract:   We describe an incidental finding of intradural lumbar disc herniation diagnosed radiographically during discography. A patient was referred to our center for discography with symptoms of worsening, intractable low back pain radiating to both hips and the left leg which was exacerbated when standing and walking. Magnetic resonance imaging of the lumbar spine revealed multiple disc bulges and lumbar facet arthroses with ligamentum flavum hypertrophy producing moderate central canal and lateral recess stenosis. Discography was performed at three levels (L3-4, L4-5, L5-S1). During fluoroscopically guided injection into L4-5 it was noted that contrast was not contained within the disc and spread intrathecally with a myelographic appearance. Computerized tomography confirmed accurate needle placement and a spread of contrast into the intrathecal space. To the best of our knowledge, this is the first report describing a finding of intradural disc herniation while performing discography. Physicians should be aware of this potential finding while performing this technique. ▪     

Efficacy of Dexmedetomidine as a Sole Sedative Agent in Small Diagnostic and Therapeutic Procedures: A Systematic Review

Dexmedetomidine is an upcoming agent with sedative, anxiolytic, and analgesic properties. This review summarizes empirical evidence for the efficacy of dexmedetomidine as a sole sedative agent, and its effectiveness for small diagnostic and therapeutic procedure, in comparison with other frequently used sedatives. All randomized controlled trials on the effect of dexmedetomidine were reviewed. Pain level, patient satisfaction, operator satisfaction, procedure duration, recovery time, and hemodynamic and respiratory characteristics were examined. A total of 1993 patients (1,621 adults; 372 children) from 35 studies were included. In the adult studies, dexmedetomidine yielded significantly lower pain levels compared to the other sedatives (in 31.25% of the included studies) and significantly more patient satisfaction (68.2%). In studies on children, more favorable results concerning respiratory safety and the level of adequate sedation were found compared to the control sedatives. Implications for future studies are discussed.