Integrative systems 715
Motor cortex stimulation for neuropathic pain syndromes: a case series experience Robert J. Buchanana,b,d, David Darrowf, Daniel Monsivaise, Zoltan Nadasdyc,g and Klevest Gjinia Neuropathic pain is a chronic condition lacking effective management and responding poorly to standard treatment protocols. Motor cortex stimulation has emerged as a new and promising therapeutic tool with outcomes potentially affected by the specific causes and location. In this study we report a series of eight cases in the neurosurgery practice of one of the authors (R.J.B.), including neuropathic pain syndromes of trigeminal or thalamic origin with or without anesthesia dolorosa. Pain relief was evaluated on the basis of comparison of Visual Analog scores at baseline and at 3 months after surgery. In addition, we assessed differences in pain relief outcomes between cases with trigeminal neuralgia and thalamic stroke, as well as cases with or without anesthesia dolorosa (i.e. pain with numbness of the affected area). Visual Analog Scale scores showed a statistically significant decrease of 4.19 (P = 0.002) at 3 months followup compared with baseline. Pain relief levels in four of five patients in the subgroup with facial pain were higher than 50%, and none of the patients in the subgroup with thalamic and phantom limb pain showed such a good outcome. Furthermore, we found larger pain relief levels in facial pain conditions with versus without anesthesia
Introduction The effective management of neuropathic pain continues to be a daunting challenge. Few novel treatment options have emerged, and the mechanism remains elusive. Motor cortex stimulation (MCS) has been used since the early 1990s [1], and it remains one of the few available treatments for medically refractory central pain [2]. Since the publication of the first series of patients, other case series and a few randomized controlled trials have demonstrated efficacy of MCS [3–5]. Two retrospective analyses of previously reported case series found the efficacy to be 56.7 and 54.6%, where a ‘Good’ outcome corresponds to at least 40–50% pain reduction [5,6]. Two prospective randomized controlled trials have also evaluated the efficacy using ‘on/off ’ periods at 1 year and found 53% (N = 10) and 63% (N = 8) improvement levels [3,4]. In the current study, we aimed to investigate and report the rates of efficacy and characteristics of patients implanted in author R.J.B.’s practice by retrospective analysis of permanently implanted patients between 2004 and 2006. Furthermore, on the basis of the limited c 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 0959-4965
dolorosa. These results point to utility of motor cortex stimulation in relieving neuropathic pain, as well as better outcomes for patients with facial pain and anesthesia dolorosa. Future studies should incorporate methods to noninvasively trial those patients who may benefit from surgical implantation to predict the outcomes and maximize their negative predictive value. NeuroReport c 2014 Wolters Kluwer Health | Lippincott 25:715–717 Williams & Wilkins. NeuroReport 2014, 25:715–717 Keywords: anesthesia dolorosa, facial pain, motor cortex stimulation, phantom limb pain, thalamic pain, visual analog scale a
Division of Neurosurgery, Seton Brain and Spine Institute, bDepartment of Psychology, University of Texas at Austin, cNeuroTexas Institute, Austin, d Department of Psychiatry, UT Southwestern Medical School, Dallas, e Department of Neurosurgery, University of Texas at Houston, Houston, Texas, fDepartment of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA and gEotvos Lorand University, Budapest, Hungary Correspondence to Robert Buchanan, MD, Seton Brain and Spine Institute, University Medical Center at Brackenridge, 1400 N. IH35, Suite 300, Austin, TX 78701, USA Tel: + 1 512 324 4816; fax: + 1 512 324 4726; e-mail: [email protected] Received 14 March 2014 accepted 20 March 2014
evidence in the literature regarding a preferential utility of MCS for neuropathic facial pain [7,8], we hypothesized that MCS would be more effective in patients with facial pain in comparison with those with central pain of thalamic origin.
Materials and methods Our case series consist of eight patients with central neuropathic pain refractory to medical therapy. Patient age ranged from 41 to 76 years, with a mean age of 58 years. All patients were right hand dominant. Two of the patients suffered from thalamic pain secondary to thalamic stroke, one right-sided and one left-sided. Both thalamic pain patients suffered from hemiparesis and anesthesia dolorosa. Five patients suffered from facial pain due to either failed surgery for trigeminal neuralgia (n = 4), of whom three also suffered from anesthesia dolorosa or idiopathic atypical facial pain (n = 1). Anesthesia dolorosa refers to diminished or eliminated sense of touch in the affected area while the malfunctioning sensation of pain is left intact. One patient suffered from phantom limb pain after an above the DOI: 10.1097/WNR.0000000000000174
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
716 NeuroReport 2014, Vol 25 No 9
elbow amputation of the left arm following a motor vehicle accident. Patients were asked preoperatively to quantify their pain using Visual Analog Scale (VAS) scores. All patients underwent and passed a general neuropsychiatric interview and testing battery. All had medically refractory pain syndromes (with no signs of spontaneous recovery) for an average of 2 years duration before MCS surgery. The patients were all discharged on postoperative day 3 and then evaluated at 3 months follow-up compared with baseline. This study was carried out following the guidelines for proper human research conduct in accordance with the Declaration of Helsinki. All patients were implanted by R.J.B. in the region of the motor cortex corresponding to the anatomical location of pain. The cortical region corresponding to their painful area was mapped using motor functional MRI (fMRI) scanning. In the operating room, the BrainLab Neuronavigation System (BrainLAB, Heimstetten, Germany) was used to localize fMRI data on a set of merged scans after registration [9,10]. The BrainLab System allowed for a small craniotomy to be fashioned directly over the region of the fMRI signal. The patient’s contralateral region of pain, hand or face, was set-up for intraoperative electromyography. An Ojemann cortical stimulator (Integra Burlington MA Inc., Burlington, Massachusetts, USA) was used to stimulate the dura over the cortex or the cortex itself to confirm the location of the target region. In five patients, the 1 4 Resume Medtronic lead (Medtronic Inc., Minneapolis, Minnesota, USA) was sewn to the dura in the epidural space, in the direction of the motor cortex over the target region. The three other patients had significant distance between dura and cortex, so the dura was opened and the lead was placed in the subdural space, directly on the cortex and secured to the dura. The patients spent one night in the ICU and then were transferred to the surgical floor for observation. A 3-day trial of MCS was performed on each patient. Patients who obtained greater than 50% relief during the trial were permanently implanted. Follow-up VAS scores were obtained at 3 months. Percentage change (% change) in VAS scores was calculated as (post-VAS – pre-VAS)/pre-VAS. Statistical analysis
Pre-VAS and post-VAS scores were analyzed with a paired t-test (two tailed). Independent samples t-test (one tailed) was used to compare the % change in VAS scores between two subgroups of patients with facial and thalamic pain. Independent samples t-test (two tailed) was used to compare the % change in VAS scores between two subgroups of patients with facial pain with or without anesthesia dolorosa. A more general linear model was also explored to examine the relationship between post-VAS and pre-VAS, age, and sex. All possible interaction terms and second order hierarchical interaction terms were evaluated with a step-wise forward regression model.
SAS version 9.2 (SAS Institute Inc., Cary, North Carolina, USA) and Excel were used for all calculations.
Results Patient demographics, information about their pain syndrome, and examined outcome variables are shown in Table 1. The average pre-VAS and post-VAS scores were 9.4 and 5.25, respectively. VAS scores showed a statistically significant average decrease of 4.19 [95% confidence interval: 2.12–6.25; t(7) = 4.08, P = 0.002], which corresponds to an improvement of 44.4% [95% confidence interval: 22.6–66.2%] in pain score at 3 months. The average final parameter settings for stimulation were an amplitude of 5.8 V, a pulse duration of 363 ms, and a frequency of 63 Hz. In addition, the change in VAS was found to be not significantly affected by pre-VAS, age, or sex. Second order interaction terms between these three dependent variables and all combinations of hierarchical inclusion failed to significantly explain variation in the outcome. The subgroup of patients suffering from facial pain (N = 5) showed a reduction of pain levels by B54%, which was statistically significantly different [t(6) = 2.76, P = 0.033] from pain relief levels in the two thalamic patients and phantom limb patient (N = 3) who experienced on average a pain relief of about 26%. Facial pain patients with anesthesia dolorosa (N = 3) showed a reduction of pain levels by B69%, which although being larger in magnitude, it was not statistically significantly different [t(3) = 2.28, P = 0.11] from pain relief levels in the two patients with facial pain without anesthesia dolorosa who experienced on average a pain relief of about 33%.
Discussion In our series of eight patients implanted for MCS, all continued to report improved pain scores by an average of nearly 45% at 3 months. This case series further contributes to the existing literature supporting the effectiveness of MCS in patients with refractory neuropathic pain. Pain relief levels in four of five patients in the subgroup with facial pain were higher than 50%, and none of the patients in the subgroup with thalamic and phantom limb pain showed such a good outcome. Although these findings are encouraging for facial pain, because of our shorter follow-up, we are not able to clarify a long-term utility of MCS for neuropathic facial pain. Nevertheless, these findings are in line with limited evidence in the literature regarding an increased effectiveness of MCS as well as repetitive transcranial magnetic stimulation of the motor cortex in relieving neuropathic facial pain [11,12].
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
MCS for neuropathic pain Buchanan et al. 717
Table 1
Demographics, disease, and outcome
Case
Age
Sex
Type of pain
1 2 3 4 5 6 7 8
65 41 56 76 76 72 56 46
Female Female Female Female Male Male Male Female
Thalamic Face Face Face Thalamic Face Phantom limb Face
Dominant hand Right Right Right Right Right Right Right Right
Preoperative VAS
Postoperative VAS
Percentage change
9.5 9 10 10 8 10 9 10
6.5 4 2 3 6.5 5 6.5 8.5
– 0.32 – 0.56 – 0.80 – 0.70 – 0.19 – 0.50 – 0.28 – 0.15
VAS, Visual Analog Scale.
Although MCS does improve pain in a significant percentage of refractory cases, especially in those with trigeminal neuralgia with anesthesia dolorosa as shown in the current study, there remain many patients without effective treatment. The increasing volume of knowledge about the possible mechanism underlying MCS and central pain should inform newer targets and screening methods to noninvasively trial those patients who may benefit from surgical implantation. We intend to trial patients with repetitive transcranial magnetic stimulation of the motor cortex before future implantations to confirm efficacy of previous studies while testing new variations to maximize the negative predictive value [13,14].
Limitations and adverse events
Our case series represents a small sample of patients treated with MCS. This sample is only a partial representation of patients treated with MCS or of patients with refractory neuropathic pain syndromes. Our case series also only takes into consideration VAS scores at 3 months, which might not reflect a long-term prognosis [15]. One patient required significantly increased voltage levels for pain relief, which resulted in two brief seizures without long-term deficit. No other adverse events were reported within the 3 months of follow-up for each patient.
References 1
2 3
4
5
6 7
8 9
10
11 12
13
14
Acknowledgements Conflicts of interest
There are no conflicts of interest.
15
Tsubokawa T, Katayama Y, Yamamoto T, Hirayama T, Koyama S. Chronic motor cortex stimulation for the treatment of central pain. Acta Neurochir Suppl 1991; 52:137–139. Canavero S, Bonicalzi V. Central pain syndrome: elucidation of genesis and treatment. Expert Rev Neurother 2007; 7:1485–1497. Nguyen J-P, Velasco F, Brugie`res P, Velasco M, Keravel Y, Boleaga B, et al. Treatment of chronic neuropathic pain by motor cortex stimulation: results of a bicentric controlled crossover trial. Brain Stimul 2008; 1:89–96. Velasco F, Argu¨elles C, Carrillo-Ruiz JD, Castro G, Velasco AL, Jime´nez F, et al. Efficacy of motor cortex stimulation in the treatment of neuropathic pain: a randomized double-blind trial. J Neurosurg 2008; 108:698–706. Fontaine D, Hamani C, Lozano A. Efficacy and safety of motor cortex stimulation for chronic neuropathic pain: critical review of the literature. J Neurosurg 2009; 110:251–256. Lima MC, Fregni F. Motor cortex stimulation for chronic pain: systematic review and meta-analysis of the literature. Neurology 2008; 70:2329–2337. Brown JA, Pilitsis JG. Motor cortex stimulation for central and neuropathic facial pain: a prospective study of 10 patients and observations of enhanced sensory and motor function during stimulation. Neurosurgery 2005; 56:290–297. Cioni B, Meglio M. Motor cortex stimulation for chronic non-malignant pain: current state and future prospects. Acta Neurochir Suppl 2007; 97:45–49. Tirakotai W, Riegel T, Sure U, Rohlfs J, Gharabaghi A, Bertalanffy H, et al. Image-guided motor cortex stimulation in patients with central pain. Minim Invasive Neurosurg 2004; 47:273–277. Tirakotai W, Hellwig D, Bertalanffy H, Riegel T. Localization of precentral gyrus in image-guided surgery for motor cortex stimulation. Acta Neurochir Suppl 2007; 97:75–79. Monsalve GA. Motor cortex stimulation for facial chronic neuropathic pain: a review of the literature. Surg Neurol Int 2012; 3 (Suppl 4):290–311. Leung A, Donohue M, Xu R, Lee R, Lefaucheur JP, Khedr EM, et al. rTMS for suppressing neuropathic pain: a meta-analysis. J Pain 2009; 10:1205–1216. Andre´-Obadia N, Peyron R, Mertens P, Mauguie`re F, Laurent B, GarciaLarrea L. Transcranial magnetic stimulation for pain control. Double-blind study of different frequencies against placebo, and correlation with motor cortex stimulation efficacy. Clin Neurophysiol 2006; 117:1536–1544. Lefaucheur J-P, Me´nard-Lefaucheur I, Goujon C, Keravel Y, Nguyen J-P. Predictive value of rTMS in the identification of responders to epidural motor cortex stimulation therapy for pain. J Pain 2011; 12:1102–1111. Raslan AM, Nasseri M, Bahgat D, Abdu E, Burchiel KJ. Motor cortex stimulation for trigeminal neuropathic or deafferentation pain: an institutional case series experience. Stereotact Funct Neurosurg 2011; 89:83–88.
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
Motor cortex stimulation for neuropathic pain syndromes: a case series experience Robert J. Buchanana,b,d, David Darrowf, Daniel Monsivaise, Zoltan Nadasdyc,g and Klevest Gjinia Neuropathic pain is a chronic condition lacking effective management and responding poorly to standard treatment protocols. Motor cortex stimulation has emerged as a new and promising therapeutic tool with outcomes potentially affected by the specific causes and location. In this study we report a series of eight cases in the neurosurgery practice of one of the authors (R.J.B.), including neuropathic pain syndromes of trigeminal or thalamic origin with or without anesthesia dolorosa. Pain relief was evaluated on the basis of comparison of Visual Analog scores at baseline and at 3 months after surgery. In addition, we assessed differences in pain relief outcomes between cases with trigeminal neuralgia and thalamic stroke, as well as cases with or without anesthesia dolorosa (i.e. pain with numbness of the affected area). Visual Analog Scale scores showed a statistically significant decrease of 4.19 (P = 0.002) at 3 months followup compared with baseline. Pain relief levels in four of five patients in the subgroup with facial pain were higher than 50%, and none of the patients in the subgroup with thalamic and phantom limb pain showed such a good outcome. Furthermore, we found larger pain relief levels in facial pain conditions with versus without anesthesia
Introduction The effective management of neuropathic pain continues to be a daunting challenge. Few novel treatment options have emerged, and the mechanism remains elusive. Motor cortex stimulation (MCS) has been used since the early 1990s [1], and it remains one of the few available treatments for medically refractory central pain [2]. Since the publication of the first series of patients, other case series and a few randomized controlled trials have demonstrated efficacy of MCS [3–5]. Two retrospective analyses of previously reported case series found the efficacy to be 56.7 and 54.6%, where a ‘Good’ outcome corresponds to at least 40–50% pain reduction [5,6]. Two prospective randomized controlled trials have also evaluated the efficacy using ‘on/off ’ periods at 1 year and found 53% (N = 10) and 63% (N = 8) improvement levels [3,4]. In the current study, we aimed to investigate and report the rates of efficacy and characteristics of patients implanted in author R.J.B.’s practice by retrospective analysis of permanently implanted patients between 2004 and 2006. Furthermore, on the basis of the limited c 2014 Wolters Kluwer Health | Lippincott Williams & Wilkins 0959-4965
dolorosa. These results point to utility of motor cortex stimulation in relieving neuropathic pain, as well as better outcomes for patients with facial pain and anesthesia dolorosa. Future studies should incorporate methods to noninvasively trial those patients who may benefit from surgical implantation to predict the outcomes and maximize their negative predictive value. NeuroReport c 2014 Wolters Kluwer Health | Lippincott 25:715–717 Williams & Wilkins. NeuroReport 2014, 25:715–717 Keywords: anesthesia dolorosa, facial pain, motor cortex stimulation, phantom limb pain, thalamic pain, visual analog scale a
Division of Neurosurgery, Seton Brain and Spine Institute, bDepartment of Psychology, University of Texas at Austin, cNeuroTexas Institute, Austin, d Department of Psychiatry, UT Southwestern Medical School, Dallas, e Department of Neurosurgery, University of Texas at Houston, Houston, Texas, fDepartment of Neurosurgery, University of Minnesota, Minneapolis, Minnesota, USA and gEotvos Lorand University, Budapest, Hungary Correspondence to Robert Buchanan, MD, Seton Brain and Spine Institute, University Medical Center at Brackenridge, 1400 N. IH35, Suite 300, Austin, TX 78701, USA Tel: + 1 512 324 4816; fax: + 1 512 324 4726; e-mail: [email protected] Received 14 March 2014 accepted 20 March 2014
evidence in the literature regarding a preferential utility of MCS for neuropathic facial pain [7,8], we hypothesized that MCS would be more effective in patients with facial pain in comparison with those with central pain of thalamic origin.
Materials and methods Our case series consist of eight patients with central neuropathic pain refractory to medical therapy. Patient age ranged from 41 to 76 years, with a mean age of 58 years. All patients were right hand dominant. Two of the patients suffered from thalamic pain secondary to thalamic stroke, one right-sided and one left-sided. Both thalamic pain patients suffered from hemiparesis and anesthesia dolorosa. Five patients suffered from facial pain due to either failed surgery for trigeminal neuralgia (n = 4), of whom three also suffered from anesthesia dolorosa or idiopathic atypical facial pain (n = 1). Anesthesia dolorosa refers to diminished or eliminated sense of touch in the affected area while the malfunctioning sensation of pain is left intact. One patient suffered from phantom limb pain after an above the DOI: 10.1097/WNR.0000000000000174
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
716 NeuroReport 2014, Vol 25 No 9
elbow amputation of the left arm following a motor vehicle accident. Patients were asked preoperatively to quantify their pain using Visual Analog Scale (VAS) scores. All patients underwent and passed a general neuropsychiatric interview and testing battery. All had medically refractory pain syndromes (with no signs of spontaneous recovery) for an average of 2 years duration before MCS surgery. The patients were all discharged on postoperative day 3 and then evaluated at 3 months follow-up compared with baseline. This study was carried out following the guidelines for proper human research conduct in accordance with the Declaration of Helsinki. All patients were implanted by R.J.B. in the region of the motor cortex corresponding to the anatomical location of pain. The cortical region corresponding to their painful area was mapped using motor functional MRI (fMRI) scanning. In the operating room, the BrainLab Neuronavigation System (BrainLAB, Heimstetten, Germany) was used to localize fMRI data on a set of merged scans after registration [9,10]. The BrainLab System allowed for a small craniotomy to be fashioned directly over the region of the fMRI signal. The patient’s contralateral region of pain, hand or face, was set-up for intraoperative electromyography. An Ojemann cortical stimulator (Integra Burlington MA Inc., Burlington, Massachusetts, USA) was used to stimulate the dura over the cortex or the cortex itself to confirm the location of the target region. In five patients, the 1 4 Resume Medtronic lead (Medtronic Inc., Minneapolis, Minnesota, USA) was sewn to the dura in the epidural space, in the direction of the motor cortex over the target region. The three other patients had significant distance between dura and cortex, so the dura was opened and the lead was placed in the subdural space, directly on the cortex and secured to the dura. The patients spent one night in the ICU and then were transferred to the surgical floor for observation. A 3-day trial of MCS was performed on each patient. Patients who obtained greater than 50% relief during the trial were permanently implanted. Follow-up VAS scores were obtained at 3 months. Percentage change (% change) in VAS scores was calculated as (post-VAS – pre-VAS)/pre-VAS. Statistical analysis
Pre-VAS and post-VAS scores were analyzed with a paired t-test (two tailed). Independent samples t-test (one tailed) was used to compare the % change in VAS scores between two subgroups of patients with facial and thalamic pain. Independent samples t-test (two tailed) was used to compare the % change in VAS scores between two subgroups of patients with facial pain with or without anesthesia dolorosa. A more general linear model was also explored to examine the relationship between post-VAS and pre-VAS, age, and sex. All possible interaction terms and second order hierarchical interaction terms were evaluated with a step-wise forward regression model.
SAS version 9.2 (SAS Institute Inc., Cary, North Carolina, USA) and Excel were used for all calculations.
Results Patient demographics, information about their pain syndrome, and examined outcome variables are shown in Table 1. The average pre-VAS and post-VAS scores were 9.4 and 5.25, respectively. VAS scores showed a statistically significant average decrease of 4.19 [95% confidence interval: 2.12–6.25; t(7) = 4.08, P = 0.002], which corresponds to an improvement of 44.4% [95% confidence interval: 22.6–66.2%] in pain score at 3 months. The average final parameter settings for stimulation were an amplitude of 5.8 V, a pulse duration of 363 ms, and a frequency of 63 Hz. In addition, the change in VAS was found to be not significantly affected by pre-VAS, age, or sex. Second order interaction terms between these three dependent variables and all combinations of hierarchical inclusion failed to significantly explain variation in the outcome. The subgroup of patients suffering from facial pain (N = 5) showed a reduction of pain levels by B54%, which was statistically significantly different [t(6) = 2.76, P = 0.033] from pain relief levels in the two thalamic patients and phantom limb patient (N = 3) who experienced on average a pain relief of about 26%. Facial pain patients with anesthesia dolorosa (N = 3) showed a reduction of pain levels by B69%, which although being larger in magnitude, it was not statistically significantly different [t(3) = 2.28, P = 0.11] from pain relief levels in the two patients with facial pain without anesthesia dolorosa who experienced on average a pain relief of about 33%.
Discussion In our series of eight patients implanted for MCS, all continued to report improved pain scores by an average of nearly 45% at 3 months. This case series further contributes to the existing literature supporting the effectiveness of MCS in patients with refractory neuropathic pain. Pain relief levels in four of five patients in the subgroup with facial pain were higher than 50%, and none of the patients in the subgroup with thalamic and phantom limb pain showed such a good outcome. Although these findings are encouraging for facial pain, because of our shorter follow-up, we are not able to clarify a long-term utility of MCS for neuropathic facial pain. Nevertheless, these findings are in line with limited evidence in the literature regarding an increased effectiveness of MCS as well as repetitive transcranial magnetic stimulation of the motor cortex in relieving neuropathic facial pain [11,12].
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
MCS for neuropathic pain Buchanan et al. 717
Table 1
Demographics, disease, and outcome
Case
Age
Sex
Type of pain
1 2 3 4 5 6 7 8
65 41 56 76 76 72 56 46
Female Female Female Female Male Male Male Female
Thalamic Face Face Face Thalamic Face Phantom limb Face
Dominant hand Right Right Right Right Right Right Right Right
Preoperative VAS
Postoperative VAS
Percentage change
9.5 9 10 10 8 10 9 10
6.5 4 2 3 6.5 5 6.5 8.5
– 0.32 – 0.56 – 0.80 – 0.70 – 0.19 – 0.50 – 0.28 – 0.15
VAS, Visual Analog Scale.
Although MCS does improve pain in a significant percentage of refractory cases, especially in those with trigeminal neuralgia with anesthesia dolorosa as shown in the current study, there remain many patients without effective treatment. The increasing volume of knowledge about the possible mechanism underlying MCS and central pain should inform newer targets and screening methods to noninvasively trial those patients who may benefit from surgical implantation. We intend to trial patients with repetitive transcranial magnetic stimulation of the motor cortex before future implantations to confirm efficacy of previous studies while testing new variations to maximize the negative predictive value [13,14].
Limitations and adverse events
Our case series represents a small sample of patients treated with MCS. This sample is only a partial representation of patients treated with MCS or of patients with refractory neuropathic pain syndromes. Our case series also only takes into consideration VAS scores at 3 months, which might not reflect a long-term prognosis [15]. One patient required significantly increased voltage levels for pain relief, which resulted in two brief seizures without long-term deficit. No other adverse events were reported within the 3 months of follow-up for each patient.
References 1
2 3
4
5
6 7
8 9
10
11 12
13
14
Acknowledgements Conflicts of interest
There are no conflicts of interest.
15
Tsubokawa T, Katayama Y, Yamamoto T, Hirayama T, Koyama S. Chronic motor cortex stimulation for the treatment of central pain. Acta Neurochir Suppl 1991; 52:137–139. Canavero S, Bonicalzi V. Central pain syndrome: elucidation of genesis and treatment. Expert Rev Neurother 2007; 7:1485–1497. Nguyen J-P, Velasco F, Brugie`res P, Velasco M, Keravel Y, Boleaga B, et al. Treatment of chronic neuropathic pain by motor cortex stimulation: results of a bicentric controlled crossover trial. Brain Stimul 2008; 1:89–96. Velasco F, Argu¨elles C, Carrillo-Ruiz JD, Castro G, Velasco AL, Jime´nez F, et al. Efficacy of motor cortex stimulation in the treatment of neuropathic pain: a randomized double-blind trial. J Neurosurg 2008; 108:698–706. Fontaine D, Hamani C, Lozano A. Efficacy and safety of motor cortex stimulation for chronic neuropathic pain: critical review of the literature. J Neurosurg 2009; 110:251–256. Lima MC, Fregni F. Motor cortex stimulation for chronic pain: systematic review and meta-analysis of the literature. Neurology 2008; 70:2329–2337. Brown JA, Pilitsis JG. Motor cortex stimulation for central and neuropathic facial pain: a prospective study of 10 patients and observations of enhanced sensory and motor function during stimulation. Neurosurgery 2005; 56:290–297. Cioni B, Meglio M. Motor cortex stimulation for chronic non-malignant pain: current state and future prospects. Acta Neurochir Suppl 2007; 97:45–49. Tirakotai W, Riegel T, Sure U, Rohlfs J, Gharabaghi A, Bertalanffy H, et al. Image-guided motor cortex stimulation in patients with central pain. Minim Invasive Neurosurg 2004; 47:273–277. Tirakotai W, Hellwig D, Bertalanffy H, Riegel T. Localization of precentral gyrus in image-guided surgery for motor cortex stimulation. Acta Neurochir Suppl 2007; 97:75–79. Monsalve GA. Motor cortex stimulation for facial chronic neuropathic pain: a review of the literature. Surg Neurol Int 2012; 3 (Suppl 4):290–311. Leung A, Donohue M, Xu R, Lee R, Lefaucheur JP, Khedr EM, et al. rTMS for suppressing neuropathic pain: a meta-analysis. J Pain 2009; 10:1205–1216. Andre´-Obadia N, Peyron R, Mertens P, Mauguie`re F, Laurent B, GarciaLarrea L. Transcranial magnetic stimulation for pain control. Double-blind study of different frequencies against placebo, and correlation with motor cortex stimulation efficacy. Clin Neurophysiol 2006; 117:1536–1544. Lefaucheur J-P, Me´nard-Lefaucheur I, Goujon C, Keravel Y, Nguyen J-P. Predictive value of rTMS in the identification of responders to epidural motor cortex stimulation therapy for pain. J Pain 2011; 12:1102–1111. Raslan AM, Nasseri M, Bahgat D, Abdu E, Burchiel KJ. Motor cortex stimulation for trigeminal neuropathic or deafferentation pain: an institutional case series experience. Stereotact Funct Neurosurg 2011; 89:83–88.
Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.
