- Email: [email protected]
Deep brain stimulation for chronic pain: Can it help?
Pain 120 (2006) 1–2 www.elsevier.com/locate/pain
Editorial
Deep brain stimulation for chronic pain: Can it help? Chronic pain was among the first diseases targeted for treatment by stimulation of deep brain structures and was considered a ‘new therapy’ at the time. Deep brain stimulation (DBS) was first introduced in the 1950s, and in the following 30 years multiple reports presented an overall impression regarding DBS for pain that lead most neurosurgeons to abandon the technique. Several factors played a role: small cohorts of patients treated (w1000 overall); inconsistent results; debate regarding best targets and the related pain syndrome; and enhanced oral opioid medications and the marked success of spinal neuromodulation (spinal cord stimulation or drug infusion pumps) in the treatment of difficult pain syndromes (Levy, 2003). Federal Drug Administration (FDA) regulations prohibited the use of DBS to treat pain, in the USA, between the late 1980s and 1990s and later the FDA designated DBS as ‘off-label’. Results of two DBS multi-center studies assigned by the FDA further hindered the use of DBS to treat chronic pain to the extent that few reports have been published in the last decade (Coffey, 2001). To chronic pain specialists, the treatment of some chronic pain syndromes remains elusive and challenging. For example, post-stroke neuropathic pain ranks highly as a difficult to treat complex pain syndrome, and despite advances regarding pain management remains difficult to control utilizing the procedures available. Motor cortex stimulation (MCS) was viewed by many as a promising treatment for difficult to manage chronic pain patients. In fact, MCS was originally suggested because of the poor response of chronic pain to DBS. Results following motor cortex stimulation treatment remain subject to short and long-term follow-up (Brown, 2005). The importance of the Owen et al. (2005) report stems from the fact that it revisits the issue of DBS as a tool to treat chronic pain. The authors’ dedication and determination in exploring the use of DBS as a treatment for chronic pain utilizing their own formulation and protocol is noteworthy. Owen et al. targeted the PVG/PAG and the sensory thalamus and did not follow the dictate of PVG/PAG for nociceptive pain, and VPL/VPM for neurogenic pain. The authors’ used their patients’ profile, which demonstrated abundant subcortical strokes (10 of 15) and selected a combined target protocol. While the notion of utilizing
combined stimulation of the sensory thalamus and PVG/PAG is not new and was described by Hosobuchi in 1983 (Hosobuchi, 1983), the astute selection of targets by the authors cannot be overlooked. Because of the general perception that DBS is less effective in treating post-stroke and thalamic pain syndromes (Levy, 2003), the decision to use DBS to treat central neurogenic pain is in itself, brave. Some trends or observations can be derived from the Owen et al. report: (1) all subcortical stroke patients had a PVG/PAG electrode as the final target, however, with two patients, one failed the trial and the other had VPL electrode (whether or not this constitutes a recommendation for use of PVG/PAG in this subgroup of patients remains unanswered), (2) it appears that tactile allodynia is responsive to the therapy, (3) the mean pain reduction in the subcortical group, those implanted with only one electrode was slightly higher than the cortical group (patients implanted with two electrodes in two targets), (4) overall success despite variability among patients was acceptable, and (5) the percentage of patients eventually implanted with a device relative to trial-only patients was also acceptable. One the other hand, the report constitutes a prospective, small, non-controlled, study group of patients. The authors have previously reported the use of N-of-1 trials to assess DBS for neuropathic pain (Green et al., 2004). However, in this report, there was no obvious control group. While the authors present some interesting results, the study design prohibits drawing any specific conclusions. However, rather than considering the report; one more article that adds to the confusion about DBS for pain, it could be considered the core of a larger multi-center randomized controlled study with involvement of a disinterested third party to evaluate pain. Highlighting the detailed specifics of the authors’ protocol and technique may result in a change of the overall concept about DBS for neuropathic pain. This report from the Oxford University group is one of a few recent reports that examines DBS to treat chronic pain and in general provides some insight and stimulates interest in re-visiting the technique as a treatment for pain. However, general consensus today remains doubtful regarding the efficacy DBS for chronic pain. To refute or verify this, further well-structured research that can stand alone as evidence is necessary and would certainly settle much of the DBS debate
0304-3959/$20.00 q 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.pain.2005.10.026
2
Editorial / Pain 120 (2006) 1–2
and perhaps provide answers to what the best stereotactic targets are for individual pain syndromes. Deep brain stimulation can be a useful tool when all other modalities have failed. Neurosurgeons, as part of a multidisciplinary pain specialist team involved in the treatment of chronic pain patients require a rich armamentarium and must be fully prepared to utilize the appropriate technique applicable to the appropriate target for any particular pain syndrome. References Brown J. Motor cortex stimulation. In: Fisher W, Burchiel K, editors. Seminars in neurosurgery: pain management for the neurosurgeon, vol. 2/3. New York: Thieme Medical Publishers Inc.; 2005. p. 177–82. Coffey RJ. Deep brain stimulation for chronic pain: results of two multicenter trials and a structured review. Pain Med 2001;2(3):183–92.
* Tel.: C1 503 494 9000.
Green AL, Shad A, Watson R, Nandi D, Yianni J, Aziz TZ. N-of-1 trials for assessing the efficacy of deep brain stimulation in neuropathic pain. Neuromodulation 2004;7(2):76–81. Hosobuchi Y. Combined electrical stimulation of the periaqueductal gray matter and sensory thalamus. Appl Neurophysiol 1983;46(1–4):112–5. Levy RM. Deep brain stimulation for the treatment of intractable pain. Neurosurg Clin N Am 2003;14(3):389–99. Owen SLF, Green AL, Stein JF, Aziz TZ. Deep brain stimulation for the alleviation of post-stroke neuropathic pain. Pain 2005;120:202–6.
Ahmed M. Raslan, MD* Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, USA E-mail address: [email protected]
Editorial
Deep brain stimulation for chronic pain: Can it help? Chronic pain was among the first diseases targeted for treatment by stimulation of deep brain structures and was considered a ‘new therapy’ at the time. Deep brain stimulation (DBS) was first introduced in the 1950s, and in the following 30 years multiple reports presented an overall impression regarding DBS for pain that lead most neurosurgeons to abandon the technique. Several factors played a role: small cohorts of patients treated (w1000 overall); inconsistent results; debate regarding best targets and the related pain syndrome; and enhanced oral opioid medications and the marked success of spinal neuromodulation (spinal cord stimulation or drug infusion pumps) in the treatment of difficult pain syndromes (Levy, 2003). Federal Drug Administration (FDA) regulations prohibited the use of DBS to treat pain, in the USA, between the late 1980s and 1990s and later the FDA designated DBS as ‘off-label’. Results of two DBS multi-center studies assigned by the FDA further hindered the use of DBS to treat chronic pain to the extent that few reports have been published in the last decade (Coffey, 2001). To chronic pain specialists, the treatment of some chronic pain syndromes remains elusive and challenging. For example, post-stroke neuropathic pain ranks highly as a difficult to treat complex pain syndrome, and despite advances regarding pain management remains difficult to control utilizing the procedures available. Motor cortex stimulation (MCS) was viewed by many as a promising treatment for difficult to manage chronic pain patients. In fact, MCS was originally suggested because of the poor response of chronic pain to DBS. Results following motor cortex stimulation treatment remain subject to short and long-term follow-up (Brown, 2005). The importance of the Owen et al. (2005) report stems from the fact that it revisits the issue of DBS as a tool to treat chronic pain. The authors’ dedication and determination in exploring the use of DBS as a treatment for chronic pain utilizing their own formulation and protocol is noteworthy. Owen et al. targeted the PVG/PAG and the sensory thalamus and did not follow the dictate of PVG/PAG for nociceptive pain, and VPL/VPM for neurogenic pain. The authors’ used their patients’ profile, which demonstrated abundant subcortical strokes (10 of 15) and selected a combined target protocol. While the notion of utilizing
combined stimulation of the sensory thalamus and PVG/PAG is not new and was described by Hosobuchi in 1983 (Hosobuchi, 1983), the astute selection of targets by the authors cannot be overlooked. Because of the general perception that DBS is less effective in treating post-stroke and thalamic pain syndromes (Levy, 2003), the decision to use DBS to treat central neurogenic pain is in itself, brave. Some trends or observations can be derived from the Owen et al. report: (1) all subcortical stroke patients had a PVG/PAG electrode as the final target, however, with two patients, one failed the trial and the other had VPL electrode (whether or not this constitutes a recommendation for use of PVG/PAG in this subgroup of patients remains unanswered), (2) it appears that tactile allodynia is responsive to the therapy, (3) the mean pain reduction in the subcortical group, those implanted with only one electrode was slightly higher than the cortical group (patients implanted with two electrodes in two targets), (4) overall success despite variability among patients was acceptable, and (5) the percentage of patients eventually implanted with a device relative to trial-only patients was also acceptable. One the other hand, the report constitutes a prospective, small, non-controlled, study group of patients. The authors have previously reported the use of N-of-1 trials to assess DBS for neuropathic pain (Green et al., 2004). However, in this report, there was no obvious control group. While the authors present some interesting results, the study design prohibits drawing any specific conclusions. However, rather than considering the report; one more article that adds to the confusion about DBS for pain, it could be considered the core of a larger multi-center randomized controlled study with involvement of a disinterested third party to evaluate pain. Highlighting the detailed specifics of the authors’ protocol and technique may result in a change of the overall concept about DBS for neuropathic pain. This report from the Oxford University group is one of a few recent reports that examines DBS to treat chronic pain and in general provides some insight and stimulates interest in re-visiting the technique as a treatment for pain. However, general consensus today remains doubtful regarding the efficacy DBS for chronic pain. To refute or verify this, further well-structured research that can stand alone as evidence is necessary and would certainly settle much of the DBS debate
0304-3959/$20.00 q 2005 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.pain.2005.10.026
2
Editorial / Pain 120 (2006) 1–2
and perhaps provide answers to what the best stereotactic targets are for individual pain syndromes. Deep brain stimulation can be a useful tool when all other modalities have failed. Neurosurgeons, as part of a multidisciplinary pain specialist team involved in the treatment of chronic pain patients require a rich armamentarium and must be fully prepared to utilize the appropriate technique applicable to the appropriate target for any particular pain syndrome. References Brown J. Motor cortex stimulation. In: Fisher W, Burchiel K, editors. Seminars in neurosurgery: pain management for the neurosurgeon, vol. 2/3. New York: Thieme Medical Publishers Inc.; 2005. p. 177–82. Coffey RJ. Deep brain stimulation for chronic pain: results of two multicenter trials and a structured review. Pain Med 2001;2(3):183–92.
* Tel.: C1 503 494 9000.
Green AL, Shad A, Watson R, Nandi D, Yianni J, Aziz TZ. N-of-1 trials for assessing the efficacy of deep brain stimulation in neuropathic pain. Neuromodulation 2004;7(2):76–81. Hosobuchi Y. Combined electrical stimulation of the periaqueductal gray matter and sensory thalamus. Appl Neurophysiol 1983;46(1–4):112–5. Levy RM. Deep brain stimulation for the treatment of intractable pain. Neurosurg Clin N Am 2003;14(3):389–99. Owen SLF, Green AL, Stein JF, Aziz TZ. Deep brain stimulation for the alleviation of post-stroke neuropathic pain. Pain 2005;120:202–6.
Ahmed M. Raslan, MD* Department of Neurological Surgery, Oregon Health & Science University, Portland, OR 97239, USA E-mail address: [email protected]