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peripheral stimulation: Surgical indications and technique
Author’s Accepted Manuscript Field/peripheral stimulation: Surgical indications & technique Raj N. Parekh
www.elsevier.com/locate/enganabound
PII: DOI: Reference:
S1040-7383(17)30042-4 http://dx.doi.org/10.1053/j.semss.2017.05.006 YSSPS614
To appear in: Seminars in Spine Surgery Cite this article as: Raj N. Parekh, Field/peripheral stimulation: Surgical indications & technique, Seminars in Spine Surgery, http://dx.doi.org/10.1053/j.semss.2017.05.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Field/Peripheral Stimulation: Surgical Indications & Technique Author: Raj N. Parekh, MD Affiliation: Department of Anesthesiology, Georgetown University Hospital Contact: [email protected]
Abstract.
Peripheral stimulation, similar to spinal cord stimulation, is a form
of neuromodulation that aims to treat chronic pain by directly targeting peripheral nerves, and thus altering peripheral pain pathways leading to pain relief. Implantation is performed within two stages. The first stage, or trial phase, is performed under local anesthesia and attempts to identify the appropriate peripheral nerve causing pain. The second stage, performed under general anesthesia, involves placement of an internal battery/generator for the implanted electrode. Indications for peripheral stimulation include: migraine, occipital neuralgia, cluster headache, neuropathic facial pain, complex regional pain syndrome, and chronic lower back pain.
Peripheral, or field, stimulation is a form of neuromodulation that has been utilized to treat chronic pain for several decades. Similar to spinal cord stimulation, peripheral stimulation is a nondestructive surgical technique used to treat pain disorders that are neuropathic in nature. Unlike spinal cord stimulation, peripheral nerve stimulation (PNS), as its name suggests, acts directly on peripheral nerves, and not on the brain or spinal cord. Technique: The most common technique for surgical implantation of a peripheral nerve stimulator usually occurs in two stages. The first stage, the trial phase, involves placing an electrode near the affected nerve, under fluoroscopic-guidance, with local anesthetic applied to the site. The patient is usually awake and affirms that lead placement is in the correct nerve distribution that correlates with the patient’s
symptoms. A trial lead extends from the electrode internally to the skin, superficially. The lead is connected an external generator. The patient can adjust the voltage applied to the nerve via the generator in order to determine if satisfactory analgesia is achieved. This trial phase usually lasts 3-7 days. Ending the trial any sooner could lead to false impressions, as the effect of the local anesthetic could be providing analgesia; moreover, some patients may need a few days to determine which settings are most suitable for them.1 If the patient obtains satisfactory analgesia, the patient undergoes the second stage, where placement of the battery/generator unit is done. The second stage is done under general anesthesia. As evident in Table 1, craniofacial pain composes a large part of the common indications for PNS. Pertaining specifically to craniofacial pathology, four common indications for PNS include: postherpetic neuralgia with damage to the cranial nerve V (trigeminal); post-traumatic neuropathic pain involving the infraorbital, supraorbital, or occipital nerve; occipital migraine; and cervicogenic occipital pain.2 Since similar treatment modalities such as spinal cord stimulation are commonly ineffective or even inapplicable for treating chronic disorders concerning the craniofacial region, PNS is becoming a growing viable option for patients suffering with these types of disorders. By selecting the appropriate patient, PNS can lead to long-term pain relief with patients suffering from craniofacial pain, all the while sparing them from long-term analgesic medications and potentially more invasive procedures. Aside from craniofacial pain, PNS can also provide long-term pain relief involving the extremities, such as patients suffering from CRPS. In a prospective case series, Hassenbusch et al. examined 32 patients undergoing PNS for CRPS, where pathology was mostly, if not entirely, concentrated within a single nerve distribution. After 2-4 days of the trialing phase, 30 patients (94%) underwent permanent implantation, as they had > 50% in pain score during the trial period. Patients were followed post-implantation for 2-4 days. Of those 30 patients, 19 (63%) of them experienced long-term good or fair pain relief. This study shows that PNS could be a viable option for patients with CRPS, as long as the pathology is restricted to a single nerve distribution; moreover, multiple pathologic nerves correlated with poor relief (p<0.01).3
One of the largest trials conducted to date on the effectiveness of an implantable peripheral nerve stimulator for the treatment of chronic pain was conducted by Mobbs et al in 2005. This study also attempts to show the potential effectiveness of PNS treating chronic pain localized to the extremities. In this retrospective study, 41 peripheral nerve stimulators were implanted in 38 patients (19 males, 19 females) with a median age of 44 years. The etiologies of the patients’ chronic pain were defined as: civilian nerve trauma, iatrogenic from surgery, iatrogenic from injection/cannulation, and nerve entrapment/tumor. 34 of the patients had upper extremity stimulators placed. This included 11 median, 10 ulnar, 9 brachial, 3 radial, and 1 suprascapular nerve implantations. At a mean follow-up of 31 months post-implantation, 61% (23/38) of patients reported > 50% pain relief compared to their preoperative pain level (p < 0.05). The other 15 patients reported only fair to poor results. Moreover, 18 of the 38 patients (47%) reported significant improvement in their activities of daily living post-implantation. This trial, while small in sample size, does show promise in the utility of peripheral implantation for chronic pain in the extremities.4 Chronic low back pain, either multifactorial or from a more specific cause such as failed back syndrome (FBS), has a whole-host of options for treatment. Chronic low back pain is one of the most common indications for the implantation of a spinal cord stimulator. However, for patients unwilling or unable to undergo that procedure, PNS offers another potentially effective option. Various studies and reviews performed by Verrills et al. have shown the great potential for PNS to be an effective and safe measure for patients suffering from chronic low back pain. In one of their studies, they looked at 14 patients diagnosed with FBS who underwent PNS implantation. 85% of these patients reported successful outcomes with an average pain reduction of 4.18 points. Of note, none on the 14 patients experienced any procedural or post-procedural complications. Verrills et al. notes that to achieve satisfactory analgesia for patients, correct lead placement is critical; moreover, in their experience, a lead depth of 10-12 mm from the surface may be optimal as this depth maximizes the target sensation, which are mediated by fast-adapting Aβ fibers, which are believed to play a critical role in mediating pain relief.56 Conclusions:
Even though there still remains a paucity of data, especially randomized controlled trials, PNS has experienced a resurgence in chronic pain management. Its applicability for a wide-range of disorders as well as relative simple implementation has made it a popular option for patients and physicians, alike. However, whether PNS can decrease the amount of analgesic medications that patients use and the necessity for more invasive, higher-risk procedures remain to be seen.
1
Mobbs RJ, Nair S, and Blum P. “Peripheral nerve stimulation for the treatment of chronic pain.” Journal of Clinical Neuroscience. 14(2007): 216-221. 2 Shaparin N, et al. “Peripheral neuromodulation for the treatment of refractory trigeminal neuralgia.” Pain Research and Management. 2015 March-April; 20(2): 63-66 3 Hassenbusch SJ, et al. “Long-term results of peripheral nerve stimulation for reflex sympathetic dystrophy.” Journal of Neurosurgery. 1996 March. 84(3) 415-423. 4 Mobbs RJ, Nair S, and Blum P. “Peripheral nerve stimulation for the treatment of chronic pain.” Journal of Clinical Neuroscience. 14(2007): 216-221. 5 Verrills P and Russo M. “Peripheral nerve stimulation for back pain.” Prog Neurolog Surg. 2015;29:127-38. 2015 Sep 4. 6 Verrills, et al. “Peripheral nerve stimulation: a treatment for chronic low back pain and failed back surgery syndrome?” Neuromodulation. Jan 2009; 12(1): 68-75.
Table 1: Indications: Indications for Peripheral Stimulation Migraine Occipital neuralgia Cluster headache Neuropathic facial pain Complex regional pain syndrome (CRPS) Type 1 and 2 Lower back pain
www.elsevier.com/locate/enganabound
PII: DOI: Reference:
S1040-7383(17)30042-4 http://dx.doi.org/10.1053/j.semss.2017.05.006 YSSPS614
To appear in: Seminars in Spine Surgery Cite this article as: Raj N. Parekh, Field/peripheral stimulation: Surgical indications & technique, Seminars in Spine Surgery, http://dx.doi.org/10.1053/j.semss.2017.05.006 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Field/Peripheral Stimulation: Surgical Indications & Technique Author: Raj N. Parekh, MD Affiliation: Department of Anesthesiology, Georgetown University Hospital Contact: [email protected]
Abstract.
Peripheral stimulation, similar to spinal cord stimulation, is a form
of neuromodulation that aims to treat chronic pain by directly targeting peripheral nerves, and thus altering peripheral pain pathways leading to pain relief. Implantation is performed within two stages. The first stage, or trial phase, is performed under local anesthesia and attempts to identify the appropriate peripheral nerve causing pain. The second stage, performed under general anesthesia, involves placement of an internal battery/generator for the implanted electrode. Indications for peripheral stimulation include: migraine, occipital neuralgia, cluster headache, neuropathic facial pain, complex regional pain syndrome, and chronic lower back pain.
Peripheral, or field, stimulation is a form of neuromodulation that has been utilized to treat chronic pain for several decades. Similar to spinal cord stimulation, peripheral stimulation is a nondestructive surgical technique used to treat pain disorders that are neuropathic in nature. Unlike spinal cord stimulation, peripheral nerve stimulation (PNS), as its name suggests, acts directly on peripheral nerves, and not on the brain or spinal cord. Technique: The most common technique for surgical implantation of a peripheral nerve stimulator usually occurs in two stages. The first stage, the trial phase, involves placing an electrode near the affected nerve, under fluoroscopic-guidance, with local anesthetic applied to the site. The patient is usually awake and affirms that lead placement is in the correct nerve distribution that correlates with the patient’s
symptoms. A trial lead extends from the electrode internally to the skin, superficially. The lead is connected an external generator. The patient can adjust the voltage applied to the nerve via the generator in order to determine if satisfactory analgesia is achieved. This trial phase usually lasts 3-7 days. Ending the trial any sooner could lead to false impressions, as the effect of the local anesthetic could be providing analgesia; moreover, some patients may need a few days to determine which settings are most suitable for them.1 If the patient obtains satisfactory analgesia, the patient undergoes the second stage, where placement of the battery/generator unit is done. The second stage is done under general anesthesia. As evident in Table 1, craniofacial pain composes a large part of the common indications for PNS. Pertaining specifically to craniofacial pathology, four common indications for PNS include: postherpetic neuralgia with damage to the cranial nerve V (trigeminal); post-traumatic neuropathic pain involving the infraorbital, supraorbital, or occipital nerve; occipital migraine; and cervicogenic occipital pain.2 Since similar treatment modalities such as spinal cord stimulation are commonly ineffective or even inapplicable for treating chronic disorders concerning the craniofacial region, PNS is becoming a growing viable option for patients suffering with these types of disorders. By selecting the appropriate patient, PNS can lead to long-term pain relief with patients suffering from craniofacial pain, all the while sparing them from long-term analgesic medications and potentially more invasive procedures. Aside from craniofacial pain, PNS can also provide long-term pain relief involving the extremities, such as patients suffering from CRPS. In a prospective case series, Hassenbusch et al. examined 32 patients undergoing PNS for CRPS, where pathology was mostly, if not entirely, concentrated within a single nerve distribution. After 2-4 days of the trialing phase, 30 patients (94%) underwent permanent implantation, as they had > 50% in pain score during the trial period. Patients were followed post-implantation for 2-4 days. Of those 30 patients, 19 (63%) of them experienced long-term good or fair pain relief. This study shows that PNS could be a viable option for patients with CRPS, as long as the pathology is restricted to a single nerve distribution; moreover, multiple pathologic nerves correlated with poor relief (p<0.01).3
One of the largest trials conducted to date on the effectiveness of an implantable peripheral nerve stimulator for the treatment of chronic pain was conducted by Mobbs et al in 2005. This study also attempts to show the potential effectiveness of PNS treating chronic pain localized to the extremities. In this retrospective study, 41 peripheral nerve stimulators were implanted in 38 patients (19 males, 19 females) with a median age of 44 years. The etiologies of the patients’ chronic pain were defined as: civilian nerve trauma, iatrogenic from surgery, iatrogenic from injection/cannulation, and nerve entrapment/tumor. 34 of the patients had upper extremity stimulators placed. This included 11 median, 10 ulnar, 9 brachial, 3 radial, and 1 suprascapular nerve implantations. At a mean follow-up of 31 months post-implantation, 61% (23/38) of patients reported > 50% pain relief compared to their preoperative pain level (p < 0.05). The other 15 patients reported only fair to poor results. Moreover, 18 of the 38 patients (47%) reported significant improvement in their activities of daily living post-implantation. This trial, while small in sample size, does show promise in the utility of peripheral implantation for chronic pain in the extremities.4 Chronic low back pain, either multifactorial or from a more specific cause such as failed back syndrome (FBS), has a whole-host of options for treatment. Chronic low back pain is one of the most common indications for the implantation of a spinal cord stimulator. However, for patients unwilling or unable to undergo that procedure, PNS offers another potentially effective option. Various studies and reviews performed by Verrills et al. have shown the great potential for PNS to be an effective and safe measure for patients suffering from chronic low back pain. In one of their studies, they looked at 14 patients diagnosed with FBS who underwent PNS implantation. 85% of these patients reported successful outcomes with an average pain reduction of 4.18 points. Of note, none on the 14 patients experienced any procedural or post-procedural complications. Verrills et al. notes that to achieve satisfactory analgesia for patients, correct lead placement is critical; moreover, in their experience, a lead depth of 10-12 mm from the surface may be optimal as this depth maximizes the target sensation, which are mediated by fast-adapting Aβ fibers, which are believed to play a critical role in mediating pain relief.56 Conclusions:
Even though there still remains a paucity of data, especially randomized controlled trials, PNS has experienced a resurgence in chronic pain management. Its applicability for a wide-range of disorders as well as relative simple implementation has made it a popular option for patients and physicians, alike. However, whether PNS can decrease the amount of analgesic medications that patients use and the necessity for more invasive, higher-risk procedures remain to be seen.
1
Mobbs RJ, Nair S, and Blum P. “Peripheral nerve stimulation for the treatment of chronic pain.” Journal of Clinical Neuroscience. 14(2007): 216-221. 2 Shaparin N, et al. “Peripheral neuromodulation for the treatment of refractory trigeminal neuralgia.” Pain Research and Management. 2015 March-April; 20(2): 63-66 3 Hassenbusch SJ, et al. “Long-term results of peripheral nerve stimulation for reflex sympathetic dystrophy.” Journal of Neurosurgery. 1996 March. 84(3) 415-423. 4 Mobbs RJ, Nair S, and Blum P. “Peripheral nerve stimulation for the treatment of chronic pain.” Journal of Clinical Neuroscience. 14(2007): 216-221. 5 Verrills P and Russo M. “Peripheral nerve stimulation for back pain.” Prog Neurolog Surg. 2015;29:127-38. 2015 Sep 4. 6 Verrills, et al. “Peripheral nerve stimulation: a treatment for chronic low back pain and failed back surgery syndrome?” Neuromodulation. Jan 2009; 12(1): 68-75.
Table 1: Indications: Indications for Peripheral Stimulation Migraine Occipital neuralgia Cluster headache Neuropathic facial pain Complex regional pain syndrome (CRPS) Type 1 and 2 Lower back pain