The patient was a 48-year-old

PRINTER-FRIENDLY VERSION AVAILABLE AT PAINMEDICINENEWS.COM Managing the Difficult Pain Case Case 1: Epidural Hematoma During a Trial Of Spinal Cord Stimulator Placement In a Morbidly Obese Patient SANJAY S. SASTRY, MD Director of Pain Management Coastal Pain Center South Daytona, Florida Dr. Sastry has nothing to disclose. The patient was a 48-year-old woman who was undergoing fluoroscopically assisted trial placement of a percutaneous spinal cord stimulator using dual Octrode lead placement in the thoracic epidural space region, specifically in the T8-T9 region. The patient had a long history of chronic low back pain secondary to lumbar radiculopathy, lumbar facet syndrome, and lumbar disk degeneration. The patient previously underwent multiple spinal interventional pain management procedures. She also has had lumbar epidural steroid injections, as well as lumbar facet and trigger point injections, all of which provided her with pain relief lasting no longer than 2 to 3 days at a time. INDEPENDENTLY DEVELOPED BY MCMAHON PUBLISHING PAIN MEDICINE NEWS SPECIAL EDITION DECEMBER 2013 37

After further discussion, and due to a history of multiple medical illnesses, the patient elected for a trial placement of a spinal cord stimulator. The patient had a previous medical history of morbid obesity, type 2 diabetes mellitus, traumatic head injury 20 years prior with post-traumatic seizures, headaches, rheumatoid arthritis, depression, and anxiety. The patient was not on any anticoagulants at the time of surgery nor was she taking any aspirin. Fluoroscopically assisted trial placement of a spinal cord stimulator was performed using dual Octrode lead placement in the T8-9 region, but placement of the Octrode leads to produce adequate stimulation proved challenging. Five minutes after the patient was placed in a prone position, she developed sinus congestion and experienced subsequent profuse sinus drainage. The patient had multiple areas of adhesions in the thoracic epidural space, which made it challenging to adequately place the leads in an appropriate region to provide a decent level of analgesia for her low back pain. Ultimately, the leads were placed at a desirable location that produced decent pain relief in the low back and legs. Bandages were placed on the wound site. The patient was taken to the postoperative recovery unit, where programming was initiated for the trial stimulator. After leaving the procedure room, the patient stated that she was not getting decent stimulation and that she was not experiencing analgesia. Multiple positions, from sitting to standing and then subsequently lying down, were requested during programming but produced no improvement. One hour after placement of the trial spinal cord stimulator, the patient was taken back to the procedure room, where her bandages were removed and the stimulator was reintroduced into her low back under fluoroscopic guidance. Lead manipulation was attempted by placing a stylet into both Octrode leads to change their position. The attempt was difficult and unsuccessful. Bandages subsequently were placed on the patient s wound site without any evidence of cutaneous hematoma or hemorrhage. As the patient was moving to a sitting position on procedure table and before she could take a step into the recovery unit, she suddenly developed severe, intractable low back pain. The patient was screaming from the severity of the pain located in the T12-L1 region; she further stated that the pain was radiating to the anterior aspect of her chest. The patient had extreme diaphoresis. Her systolic and diastolic blood pressures elevated 20 mm Hg and her heart rate increased to 120 bpm. The patient continued to state the pain was substantially increasing. She was flailing her lower extremities secondary to the severity of the pain. Emergency medical assistance was subsequently called. The patient was taken to the emergency department (ED) within 10 minutes of the severe increase in low back pain. After hospital ED admission, a magnetic resonance imaging test of the thoracolumbar spine demonstrated epidural hematoma at T12 level with deviation of the cord. The patient was given IV opioids to reduce her pain syndrome. She said that the pain relief, regardless of the dosage of opiates, was not substantial. Neurosurgery was consulted and discussed with the patient other options, including watching and waitng for resolution versus emergency drainage of the spinal epidural hematoma. The patient elected for drainage of the hematoma. She was taken immediately to the operating room, where the drainage procedure was performed without any complications. The patient was subsequently discharged from the hospital in stable condition without any neurologic sequelae. Conclusion Prone position in this morbidly obese patient possibly produced aorto-caval compression, which led to venous congestion, in turn causing the sinus drainage and probably engorgement of the epidural venous system. Furthermore, lead manipulation traumatized the engorged epidural venous plexus leading to the epidural hematoma. Early detection and awareness of a sudden increase in the severity of a patient s pain syndrome should be addressed immediately and not ignored. The presence of a moderate to large epidural hematoma was addressed by the surgical intervention of drainage. Early response helped to reduce any neurologic sequelae for the patient. 38 INDEPENDENTLY DEVELOPED BY MCMAHON PUBLISHING

The Evolution of Spinal Neuromodulation Case 2: Dorsal Root Ganglion Spinal Cord Stimulation Case 3: High-Frequency Spinal Cord Stimulation TIMOTHY R. DEER, MD President Elect, International Neuromodulation Society Board of Directors, American Academy of Pain Medicine American Society of Interventional Pain Physicians The Center for Pain Relief Charleston, West Virginia PAUL VERRILLS, MBBS, FAFMM, MPAINMED, FIPP Metro Spinal Clinic Melbourne, Australia ANTHONY ESPINET, MD, BSC, FRCA, FFPMANZCA The Pain Doctors Gold Coast, Queensland Australia Disclosures: Dr. Deer is a consultant for Bioness, Globus, Medtronic, Nevro Corporation, Spinal Modulation, and St. Jude Medical. Dr. Verrills is a consultant for ArthroCare, Boston Scientific, Medtronic, Mundipharma, Nevro Corporation, Spinal Modulation, St. Jude Medical, and QIG. Dr. Espinet has nothing to disclose. Spinal cord stimulation (SCS) is a critical part of the pain care algorithm. This therapy involves placing stimulating electrodes on a target in approximation to the spinal cord and then supplying power and programming from an implanted generator. The use of SCS has become very important in the algorithm of neuropathic pain as the failure of opioids has led to poor outcomes and significant problems in society. Traditionally, this therapy has been provided by placing a lead above the dorsal columns of the spinal cord and supplying energy at low frequencies (200 khz or less). This article focuses on 2 fascinating advances that currently are changing the field in the European Union and Australia. These therapies, dorsal root ganglion (DRG) SCS and high-frequency (HF) SCS, are currently only available as investigational devices in the United States. Background and History of DRG SCS The DRG is the processing center for the spine. All pain sources from the peripheral nervous system travel through this structure to transmit signals to the spinal cord. When a pain state occurs, the fibers of the DRG become hypersensitive and neurotransmitters are released to change the chemical milieu. This change in neural response makes the DRG a prime target for intervention. Novel leads have been specifically designed to be placed around the DRG to neuromodulate this structure and change the pain signal. Deer performed the first in man concept case in 2008, followed by a short-term feasibility study and subsequently a multicenter analysis of efficacy. This large study led to approval for the device in the European Union and Australia. The experience in those countries has led us to understand patients who PAIN MEDICINE NEWS SPECIAL EDITION DECEMBER 2013 39

are appropriate candidates, including those with foot pain, neuropathy, causalgia of the limb, chest wall pain, groin pain, and axial back pain. Here, we focus on a typical patient experience with DRG SCS. Patient History A 42-year-old woman presented to the pain clinic with a 6-month history of chronic pain following multiple abdominal surgeries and a 15-year history of low back pain radiating down her left lower limb in the L5 nerve distribution. Her abdominal pain was most distressing. The pain was located in the left upper abdominal wall and was constant and severe, with a visual analog scale (VAS) score of 8/10, and was aggravated by movement or activity. The patient was intolerant of multiple classes of pain medications. She had tried many different interventional treatments during the past 10 months, including epidural injections, radiofrequency therapy and cryotherapy of intercostal nerves, injection of botulinum toxin into the rectus abdominus muscles, and conventional SCS (dorsal column stimulation, ventral stimulation, and paravertebral gutter stimulation); her pain persisted despite treatment. The patient was very depressed and cried often. She was under the care of a psychologist and a psychiatrist, and was perceived to be stable for a trial of DRG SCS (spinal modulation). The patient had a trial of DRG stimulation in May 2013. Figure 1 shows the patient s preoperative pain diagram. DRG leads were placed at the left T8 DRG and bilateral L2 DRG. DRG Leads Parameter Settings The left T8 DRG lead: electrode contacts (1+ 2-): 475uA, 130us, 20Hz. The left L2 DRG: electrode contacts (2+ 4-): 475uA, 200us, 20Hz. The right L2 DRG: electrode contacts (2+ 3-): 475uA, 160us, 20Hz. Both L2 leads provided excellent pain area coverage and pain relief; the T8 lead gave 100% coverage of the painful area and pain relief. Low current settings for all leads were maintained. Low current is common with DRG leads because of the lack of cerebrospinal fluid in the area, which leads to extremely low energy requirements (Figures 2-6). Patient Feedback and Outcome One week after DRG implant, the patient reported VAS scores of 0/10 for her abdominal pain area and 2/10 for her lower back pain area. She was extremely happy with the stimulation and the level of pain relief. The patient was able to reduce her pain medications postoperatively. She reported that her DRG stimulation felt like a gentle soothing sensation. One month after the trial, the patient received a permanent implant at the same sites used in the trial. The patient was followed monthly for the next 5 months, and her VAS scores in the abdomen and back have remained at the same level (0/10 for the abdomen and 1/10-2/10 for back pain). The patient reported that she has been given back her quality of life. Figure 1. Preoperative pain diagram. Figure 2. T8 DRG A/P view. 40 INDEPENDENTLY DEVELOPED BY MCMAHON PUBLISHING

Figure 3. T8 DRG lateral view. Figure 4. L2 DRG bilateral A/P view. Figure 5. L2 DRG lateral view. Figure 6. Use of sheath for bilateral DRG Placement. PAIN MEDICINE NEWS SPECIAL EDITION DECEMBER 2013 41

High Frequency SCS At 10,000 Khz BACKGROUND AND HISTORY OF HF10 SCS The use of conventional SCS is considered a tonic low-frequency state that causes paresthesia. Paresthesia mapping has been a hallmark of successful stimulation dating back to the beginning of electrical neuromodulation in 1967. During landmark work on the possible benefit of HF stimulation, investigators and patients were surprised to find that pain relief could be accomplished in the absence of paresthesia. Subsequent work led to the use of HF SCS to treat axial back pain and for patients who had failed back surgery. Interestingly, clinical evidence obtained in a multicenter prospective fashion has been very positive and supports only the frequency at 10,000 khz. Attempts at 5,000 khz have been no better than placebo, and stimulation at 1,000 khz has been studied only in the rat model. PATIENT HISTORY The patient is a 74-year-old man with complicated scoliosis who presented with severe ongoing neuropathic back and leg pain (numeric pain rating scale score, 7/10-9/10) following failed back surgery after a boating accident 8 years ago. The pain pattern was in the neck, lower back, lower limb, buttock, and left ankle. The patient did not respond to regular medications and Figure 8. Conventional leads. Figure 7. Bilateral sacrel leads. Figure 9. HF10 leads. 42 INDEPENDENTLY DEVELOPED BY MCMAHON PUBLISHING

Table. High-Frequency SCS Outcomes Outcome Measure Baseline Post conventional SCS Post Nevro HF10 SCS Trial 6 months post HF10 SCS Pain (NPRS) 7.0 9.0 0 2.0 Depression (DASS21) 30 18 10 6 Stress (DASS21) 41 12 8 0 Disability (ODI) 22 15 10 12 Analgesic use No change No change Decreased Global Impression of Change Very much improved Very much improved conventional therapies (physiotherapy, massage therapy, myotherapy, and caudal injections). He failed to respond positively to trials of conventional sacral and SCS (Figures 7 and 8). CLINICAL HISTORY A trial of HF SCS was performed with 2 percutaneous leads at the T9-T10 level, and a frequency of 10,000 khz was initiated. The trial proved successful and a permanent implant was placed (Nevro). OUTCOME After the HF10 SCS and the implantable pulse generator implant (Figure 9), the patient reported resolution of back pain, decreased medication use, and improved function, all of which were sustained at 6 months (Table). The patient s device recharging was at regular and manageable intervals, and his satisfaction level was very high. No complications were reported. Discussion For pain control, the use of conventional SCS involving the placement of leads over the dorsal columns and stimulating the cord at low-frequency tonic waveforms is a treatment option that benefits many patients. At this time, we do not advocate that all patients be administered the new modalities discussed in this paper ;however, there is no doubt that some patients who are currently treated with SCS will have greater benefit from DRG SCS or HF10 SCS. We also feel that many patients who currently do not have the option of SCS may be candidates now, expanding the patient population that may benefit from these options instead of addictive medications, repeat surgeries, or destructive procedures. In the future, it may be possible to trial patients with conventional SCS, DRG SCS, and HF10 SCS in the same setting. In addition to the cases noted here, new waveforms such as burst stimulation are being developed that may lead to salvage of patients who no longer respond to conventional SCS. This is an extremely exciting time for our patients and those who are devoted to improving the care of patients with pain. These advances truly will lead to major improvements for people who live with pain and for professionals who strive to advance the field. Selected Reading 1. Liem L, Russo M, Huygen FJ, et al. A multicenter, prospective trial to assess the safety and performance of the spinal modulation dorsal root ganglion neurostimulator system in the treatment of chronic pain. Neuromodulation. 2013 May 13. doi: 10.1111/ner.12072. [Epub ahead of print] 2. Deer TR, Grigsby E, Weiner RL, et al. A prospective study of dorsal root ganglion stimulation for the relief of chronic pain. Neuromodulation. 2013;16(1):67-71; discussion 71-72. 3. Pope JE, Deer TR, Kramer J. A systematic review: current and future directions of dorsal root ganglion therapeutics to treat chronic pain. Pain Med. 2013 Jun 26. doi: 10.1111/pme.12171. [Epub ahead of print] 4. Tiede J, Brown L, Gekht G, et al. Novel spinal cord stimulation parameters in patients with predominant back pain. Neuromodulation. 2013;16(4):370-375. 5. Van Buyten JP, Al-Kaisy A, Smet I, et al High-frequency spinal cord stimulation for the treatment of chronic back pain patients: results of a prospective multicenter European clinical study. Neuromodulation. 2013;16(1):59-65; discussion 65-66. 6. De Ridder D, Plazier M, Kamerling N, et al. Burst spinal cord stimulation for limb and back pain. World Neurosurg. 2013 Jan 12. pii: S1878-8750(13)00101-0. doi: 10.1016/j.wneu.2013.01.040. [Epub ahead of print] PAIN MEDICINE NEWS SPECIAL EDITION DECEMBER 2013 43