Dorsal Root Ganglion Stimulation for the Management of Chronic Neuropathic Pain: A Retrospective Case Series during Four Years follow-up in a Single Center

Alfonso Papa1, *, Elisabetta Saracco1, Maria Teresa Di Dato1, Pietro Buonavolontà1, Anna Maria Salzano1, Dario Tammaro1, Beniamino Casale1
1 Department of Pain - Azienda Ospedaliera Dei Colli, Monaldi Hospital, Napoli, Italy

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© 2020 Papa et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at Department of Pain - Azienda Ospedaliera Dei Colli, Monaldi Hospital, Via Leonardo Bianchi,1 – 80131 Napoli, Italy; Tel: +39-081-7064137; Fax: +39-081-7062932; E-mail:



The dorsal root ganglion (DRG) is involved in the transduction of pain signals to the central nervous system (CNS) and undergoes a number of physiopathological changes during chronic pain. The purpose of this data collection was to evaluate the long-term safety and efficacy of DRG stimulation for the treatment of chronic pain and its impact on functional aspects.

Materials and Methods:

Forty-four subjects with non-reactive chronic neuropathic pain syndrome were implanted with DRG stimulation.

Patients were evaluated at baseline as well as at 15, and 30 days, and at 3, 6, 12, 24, 36 and 48 months after medical intervention/surgery using the Visual Analogic Scale (VAS), which measures pain intensity, and the Oswestry Scale, for the estimation of disability (ODI).


After four years of simulation, VAS and ODI showed a statistically significant reduction throughout the follow-up period. The average pain relief obtained after 48 months of treatment was 74.1% ± 3.4.


The results of this data collection demonstrate the feasibility of DRG stimulation, the correspondence between the clinical indications at the DRG implant and what is commonly found in the literature on this technique.(18,20) Patients defined as clinical responders to DRG stimulation and so implanted with definitive IPG showed a sustained and long term efficacy. Eight patients had previously been implanted with a traditional SCS without any clinically relevant efficacy; they were then explained for unsatisfactory results. Six of them (75%) were later implanted with DRG, with long-term effectiveness. Another advantage of this therapy is the absence of positional effects and lead migration. The adverse events proved to be independent of the anatomical level of insertion; moreover, this series of cases show a lower incidence of lead migration than reported in the literature. In summary, DRGs have been ignored for too long, probably due to the technical difficulty of reaching their deep, almost extra-spinal anatomical position.

Keywords: Chronic pain, Dorsal root ganglion (DRG), Spinal cord stimulation (SCS), Visual analog scale (VAS), Extra-spinal anatomical position, Anatomical level of insertion.


Chronic pain syndromes represent a considerable challenge for pain therapist, despite the most recent developments in the minimally invasive field [1]. Indeed, a high percentage of chronic pain patients are still unable to achieve adequate pain relief with pharmacotherapy, physical therapy, occupational therapy, minimally invasive techniques or surgery [1]. From an economic and social point of view, the impact of chronic pain therefore remains very high [2, 3]. In recent years, a great deal of technological research has been conducted in the field of neuromodulation, in an attempt to provide a solution for patients who are not yet adequately treated, culminating in the identification of promising new stimulation goals, such as the dorsal root ganglion (DRG) [4-7].

DRG, despite its key role in neuromodulation therapy, has been somewhat neglected for years. Recent molecular studies, however, have brought to light the fundamental role of this structure in the origin, development and maintenance of chronic pain [8, 9].

The DRG is involved in the transduction of pain signals to the central nervous system (CNS) and undergoes a series of physiopathological modifications during states of chronic pain. These variations modify the membrane properties of sensory neurons in the first order, and thus their neurophysiological characteristics. Given the alterations in the biophysical properties of these cellular elements, neuromodulatory therapies may preferentially target these elements [10-13].

Spinal cord stimulation (SCS) has been widely used over the last twenty years as an efficient therapeutic option when drug therapies and minimally invasive treatments have proven ineffective in neuropathic pain control [7]. This technique, however, is limited by the need to treat extremely selective and circumscribed areas, such as feet, groin or legs; all these neuronal targets are best covered by DRG selective stimulation [13, 14]. The purpose of this data collection was to evaluate the short- and medium-term safety and efficacy of DRG stimulation for the treatment of chronic pain and its impact on functional aspects.


DRG stimulation with a dedicated device was started in October 2013 at the Department of Pain AO Ospedali Dei Colli - Monaldi Hospital. We retrospectively analyzed the medical records of all patients undergoing DRG Stimulation from the date of the first implantation in October 2013, selecting all patients who have completed a 48-month follow-up. This series of retrospective cases also includes patients where the study failed. For all patients, following the standards of actual clinical practice, the inclusion and exclusion criteria for the implant should be considered which is shown in Table 1.

Always following our real clinical practice for all the patients we used: Visual Analogic Scale (VAS) measuring the intensity of pain Oswestry Scale (ODI) for an estimation of disability at the baseline and 15, and 30 days, and 3, 6, 12, 24, 36 and 48 months after medical intervention/operation. During this period all adverse events that occurred were recorded.

According to the previous criteria, from October 2013 to the end of November 2015, 44 patients with non-reactive chronic neuropathic pain syndrome were selected and subjected to DRG simulation testing. All patients were contacted to provide written consent to participate in this data collection and all information was collected anonymously. A previous failed SCS was recorded for all patients.

Continuous data are presented as an average ± SD. For all the variables collected continuously, the differences before and after the DRG plant were evaluated using ANOVA for the analysis of repeated measurements with the Bonferroni adjustment for post-hoc comparisons. All p values at 2-tail <0.05 were considered statistically significant. The STATUS value ver. 13 statistical package was used for the analysis.


One or more quadripolar percutaneous leads were implanted in the posterior roots of the ganglia related to the previously mapped pain area. With local anesthesia plus MAC (Monitored Anaesthesia Care), leads were placed with an epidural approach, with the loss-of-resistance technique. The interlaminar space selected for the epidural approach was one or two spaces lower than the target. The leads are navigated through the epidural space and then placed in the intervertebral foramen near the DRG under the fluoroscopic approach and guidance. The paresthesia is evoked to confirm the correct position of the conductors; the conductors were then connected to an EPG (External Pulse Generator) via test extensions; these were removed at the end of the test period and replaced with the final ones. All patients underwent a trial period to verify the effectiveness of the stimulation. Patients classified as respondents (pain relief >=50%) at the end of the trial phase underwent the final neurostimulator implant (Axium, St. Jude Medical-Plano TX) [15-17].

Table 1. Real life inclusion and exclusion criteria.
Inclusion criteria:
Therapeutic profile (pharmacological/non-pharmacological) stable over the 30 days preceding admittance, without significant variations in surgical or infiltrative therapy;
Psychological screening has not elicited any contraindications.
The patient has a full understanding of the assessment, implantation, follow-up processes, and risk of complications
Age over 18 years;
Absence of significant comorbidity.
Exclusion criteria:
The presence of another clinically significant or disabling persisting pain condition.
A coagulation disorder, immunosuppression, or other conditions associated with an unacceptable surgical risk.
An expected inability to receive or operate the SCS system.
A life expectancy of less than one year.
An expected or planned pregnancy.


Table 2 also specifies the pathologies of the 5 patients indicated as “others”, including the outcome of the study. Compared to a previous neurostimulation procedure, 8 patients had already performed a failed SCS study. (4 for PHN, 3 for CRPS and 1 for FBSS). Of these, only 2 patients, both with PHN, did not respond positively to DRG stimulation. In 44 patients, a total of 72 leads (average of 1.7 ± 0.7 per patient) were placed epidurally at cervical (7%), thoracic (21%), lumbar (58%) and sacral (14%) spinal level. The implant was unilateral in 27 patients (61%). At the end of the trial phase, 39 patients (89%) were shown to be responsive to DRG stimulation and internal pulse generator were implanted, while for the 5 non-responsive patients the leads were explanted.

In implanted patients (N=39) the average degree of pain relief was 72% ± 10.1, compared to 11% ± 3.4 in patients who did not undergo the final system implantation (N=5). After the DRG simulation for implanted patients only, the SEA showed a statistically significant reduction during the entire observation period (baseline SEA = 85.9 ± 9.2, VAS15days = 28.7 ± 7. 2, SEA30 days = 24.6 ± 5.2, SEA3 months = 15.1 ± 4.3, SEA6 months = 14.3 ± 4.7, SEA12 months = 11.5 ± 2.7, SEA24 months = 13.9 ± 3.1, SEA36 months = 14.6 ± 5.1, SEA48 months = 19.8 ± 5.9, p = 0.00001). In fact, the SEA scores recorded at each subsequent examination were significantly lower than the basic value (Fig. 1).

The average pain relief obtained after 48 months of treatment was 74,1% ± 3.4, a percentage absolutely comparable to that obtained at the end of the trial phase. The average percentages during the whole follow-up are shown in Fig. (2).

In addition, the disability index, measured according to the Oswestry Scale, showed a significant improvement during the entire follow-up period (p = 0.00001), with a reduction from 67.5% ± 15.6 at the baseline to 25.9% ± 8.8 after 48 months of treatment. In addition, all scores recorded during follow-up visits were significantly lower than the baseline value (OSW15days = 30.6% ± 7.2, OSW30days = 28.0% ± 7.3, OSW3months = 23.1% ± 8.7, OSW6months = 20.7% ± 9.1, OSW12months = 21.1% ± 8.8, OSW24months = 23.8% ± 7.6, OSW36months = 26.8% ± 8.2, OSW48months = 28.9% ± 7.8) (Fig. 3).

During the follow-up, 9 adverse events occurred, with a complication rate of 20%. Infection was the most frequent side effect, occurring in 3 patients (7%). In all 3 cases, the implant was removed. Two patients underwent implant removal due to rejection. Bilateral lead migration occurred in 1 patient and required an additional surgical procedure. Out of 72 leads implanted, only 2 migrated, with a 3% dislocation rate. All complications occurred within 6 months of implantation, no complications were recorded in the remaining time period. We kept follow-up active for all 34 remaining patients for 48 months.

Considering only the most frequent etiologies (FBSS, CRPS, radicular pain, post-herpetic neuralgia (PHN) and chronic post-surgical pain), a significantly lower percentage of responders (p = 0.041) was recorded among patients with PHN than among the other groups. At the 12th, 24th, 36th and 48th month of follow-up, the reduction in the VAS scale, the pain relief achieved and the improvement in functional aspects were comparable in all the subgroups considered.

Fig. (1). - DRG significantly reduced pain. At each follow up VAS score was significantly lower than baseline condition (* = p<0.001, post hoc analysis, Bonferroni adjustment).

Table 2. Demographic data and pain etiology. *(Implant/Failed). ** Other: Pelvic pain (Implanted), Monosegmentary spinalcord ischemic pain (Failed), Postsurgical knee pain (Implanted), Chronic pain after thoracic vertebral fracture (Failed), Chronic pancreatitis (Failed).
Variable N %
Male 26 64%
Age at implant (yrs) 58±23 NA
Failed Back Surgery Syndrome 12 (12/0)* 28%
Complex regional pain syndrome 8 (8/0)* 18%
Radicular pain 8 (8/0)* 18%
Postherpetic neuralgia 5 (3/2)* 11%
Chronic postsurgical pain 4 (4/0)* 9%
Limb phantom/ stump pain syndrome 2 (2/0)* 5%
Other ** 5 (2/3)* 11%
Fig. (2). - DRG pain relief through 12 months post-implant.

Fig. (3). - Functional disability measured by the Oswestry Disability Index was significantly and durably reduced through all follow up visits (*=p<0.001, post hoc analysis, Bonferroni adjustment).


Since the introduction of a dedicated system for DRG stimulation, it was immediately evident how this type of therapy could improve pain relief for patients with chronic neuropathic pain [18-23]. Equally evident is the effectiveness of DRG stimulation in diseases such as CPRS [24-25], FBSS [26-27], phantom limb syndrome [28-30], amputation pain [31-32] and post-surgical pain [33-35]. In particular with regard to CPRS in 2017, Deer et al. in the ACCURATE study highlighted how DRG stimulation significantly reduces the VAS values in these patients, demonstrating to be superior to SCS [36]. With regard to the other indications, there are a number of cases concerning the efficacy of DRG stimulation in postherpetic neuralgia [37-38]. Also for other pathologies, present in our clinical history, such as ischemic neuropathic pain, groin pain, diabetic neuropathy, there is literature to support [39-44]. In this series of cases, these pathologies have been treated mainly by reproducing in real life the results described in the literature [39-44]. Compared to the literature, where the follow-ups are shorter, the respondents in our series maintain pain relief at 48 months.

The results of this data collection demonstrate the feasibility of DRG stimulation, the correspondence between clinical indications to DRG implantation and what is commonly found in literature about this technique [18, 20] Patients defined as clinical respondents to DRG stimulation and then implanted with definitive IPG showed sustained and long-term efficacy. Eight patients had previously been implanted with a traditional SCS without any clinically relevant efficacy; therefore they were explained for unsatisfactory results. Most of these were subsequently implanted with DRG leads, with long-term efficacy. In addition, as with traditional SCS, the procedure is minimally invasive and does not change the operating time or hospital stay. Another advantage of this therapy is the absence of positional effects and lead migration. Adverse events were found to be independent of the level of anatomical insertion. As regards the complications observed in our retrospective analysis, we detect lower rates than the broad case studies analyzed by Huygen et al. These authors observed 11.8% of electrode migrations and dislocations, 10.2% of pain at the pocket site and 5.1% of infections [45]. For these differences in our case studies it is necessary to make some considerations. These patients were operated in the first period of introduction of DRG stimulation systems, for which the first dedicated electrode new to the market was used. It should be remembered that this was equipped with a Tip Ball that significantly reduced its dislocation. The Tip Ball was subsequently removed from production due to difficulties in removing the electrodes. As far as the pain in the pocket site is concerned, it was probably not highlighted in our case studies, since in the operating protocol the IPG was always positioned in the abdominal region. Finally, the infection rate in our series of cases is congruent with the literature. It must be considered that with the passage of time, increased experience reduces the rate of complications. [46, 47].

Our results in maintaining Pain Relief over time are satisfactory. A recent review showed that between 20% and 40% of patients undergoing SCS, pain relief decreases over time due to central nervous system tolerance [48, 49]. Loss of efficacy is the main cause of explantation for SCS systems [50]. In SCS, the activation of the descending pain inhibition system certainly occurs [51]. Taghipour et al. have suggested that stimulation of dorsal column neurons may cause the release of neurotransmitters at the dorsal horn level from the efferent fibers of periaqueductal grey matter (PAG), and rostral ventromedial marrow (RVM), with antinociceptive effects [52]. Another study proposes the following mechanisms to explain the effects of SCS on chronic pain [53]. In chronic neuropathic pain, the mechanism of disinhibition of the dorsal horn circuits that would allow the Aß fibers to access the lamina I neurons would be particularly increased. SCS would amplify the anti-dromic impulses of the Aß fibers by energizing the lamina I fibers in the dorsal horn.

DRG stimulation unlike SCS acts directly on the primary sensory neurons of the DRG, which represent an important target in the pathophysiological mechanism of many types of neuropathic pain [54]; the DRG contains the primary sensory neuron (PSN) cell bodies and their T-junctions. It is precisely in the T-junction that the failure of the central projection of sensory information can be jammed, just as in this area modulation occurs for the sensory control of peripheral stimuli, especially painful ones [55-57]. Morgalla et al. have hypothesized that DRG stimulation can normalize, maintaining this effect indefinitely over time, the transmission of painful rye from the periphery to the supraspinal levels [58].

Despite the current dominance of conventional SCS, stimulation peripheral nerves stimulation has again attracted the interest of pain therapists over the past two and a half decades. Thus, nerve roots and the brain have again become the main focus of interventions for the treatment of pain (basal ganglion and thalamus) and psychiatric disorders (internal capsule, cortical and subcortical regions). In summary, DRGs have been ignored for too long, probably due to the technical difficulty of reaching their anatomical position. In conclusion, we believe that this technique should always be taken into consideration, especially in cases where SCS does not give optimal results, despite the technical difficulties of implantation.


AP defined this data collection and interpreted the data. AP also analyzed the data and drafted the manuscript. The other authors collected the data and reviewed the manuscript. All authors approved the final manuscript.


In our hospital, the approval of the Ethics Committee is not required for a retrospective observational study for a case series; for this reason no request was made.


Not Applicable.


All patients have signed consent for data publication.


Clinical practices were carried out according to standard of CARE; no changes to common clinical practice occurred for the treatment of these patients.


No funding was obtained for this study.


AP is the consultant (proctor) to St Jude Medical/ABBOTT. Other Authors have nothing to disclose.


Declared none.


[1] Deer TR, Grigsby E, Weiner RL, Wilcosky B, Kramer JM. A prospective study of dorsal root ganglion stimulation for the relief of chronic pain. Neuromodulation 2013; 16(1): 67-71.
[2] Gureje O, Von Korff M, Simon GE, Gater R. Persistent pain and well-being: a WorldHealth Organization study in primary care. JAMA 1998; 280(2): 147-51.
[3] Blyth FM, March LM, Brnabic AJ, Cousins MJ. Chronic pain and frequent use of health care. Pain 2004; 111(1-2): 51-8.
[4] Shealy CN, Taslitz N, Mortimer JT, Becker DP. Electrical inhibition of pain: experimental evaluation. Anesth Analg 1967; 46(3): 299-305.
[5] Deer T, Bowman R, Schocket SM, et al. The prospective evaluation of safety and success of a new method of introducing percutaneous paddle leads and complex arrays with an epidural access system. Neuromodulation 2012; 15(1): 21-9.
[6] Ross E, Abejon D. Improving patient experience with spinal cord stimulation: implications of position-related changes in neurostimulation. Neuromodulation 2011.
[7] Liem L, Russo M, Huygen FJPM, 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; 16(5): 471-82.
[8] Sapunar D, Kostic S, Banozic A, Puljak L. Dorsal root ganglion - a potential new therapeutic target for neuropathic pain. J Pain Res 2012; 5: 31-8.
[9] Van Zundert J, Patijn J, Kessels A, Lame I, van Suijlekom H, van Kleef M. Pulsed radiofrequency adjacent to the cervical dorsal root ganglion in chronic cervical dorsal root ganglion in chronic cervical radicular pain: a double blind sham controlled randomized clinical trial. Pain 2007; 127: 173-82.
[10] McCallum JB, Kwok WM, Sapunar D, Fuchs A, Hogan QH. Painful peripheral nerve injury decreases calcium current in axotomized sensory neurons. Anesthesiology 2006; 105(1): 160-8.
[11] Rush AM, Dib-Hajj SD, Liu S, Cummins TR, Black JA, Waxman SG. A single sodium channel mutation produces hyper- or hypoexcitability in different types of neurons. Proc Natl Acad Sci USA 2006; 103(21): 8245-50.
[12] Fields RD. New culprits in chronic pain. Sci Am 2009; 301(5): 50-7.
[13] Krames ES. The dorsal root ganglion in chronic pain and as a target for neuromodulation: a review. Neuromodulation 2015; 18(1): 24-32.
[14] North RB. Neural interface devices: spinal cord stimulation technology. Proc IEEE 2008; 96: 1108-19.
[15] St. Jude Medical [now Abbott]. Proclaim™ DRG Implantable Pulse Generator. Clinician's Manual 2017.
[16] St. Jude Medical [now Abbott]. Axium™ Neurostimulator System Physician Implant Manual 2016.
[17] Vancamp T, Levy RM, Peña I, Pajuelo A. Relevant anatomy, morphology, and implantation techniques of the dorsal root ganglia at the lumbar levels. Neuromodulation 2017; 20(7): 690-702.
[18] 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; 14(10): 1477-96.
[19] Deer TR, Levy RM, Kramer JM. Interventional perspectives on the dorsal root ganglion as a target for the treatment of chronic pain: a review. Minim Invasive Surg Pain 2013; 1: 23-33.
[20] Liem L, Russo M, Huygen FJ, et al. One-year outcomes of spinal cord stimulation of the dorsal root ganglion in the treatment of chronic neuropathic pain. Neuromodulation 2015; 18(1): 41-8.
[21] 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; 16(5): 471-82.
[22] Nijhuis H, Liem L, Huygen F. A post-market cohort to assess the performance of a neurostimulator system for the management of intractable chronic back pain. Neuromodulation 2013; 16e140
[23] Gao Z, Feng Y, Ju H. The different dynamic changes of nerve growth factor in the dorsal horn and dorsal root ganglion leads to hyperalgesia and allodynia in diabetic neuropathic pain. Pain Physician 2017; 20(4): E551-61.
[24] Van Buyten JP, Smet I, Liem L, Russo M, Huygen F. Stimulation of dorsal root ganglia for the management of complex regional pain syndrome: a prospective case series. Pain Pract 2015; 15(3): 208-16.
[25] Deer TR, Levy RM, Kramer J, et al. Dorsal root ganglion stimulation yielded higher treatment success rate for complex regional pain syndrome and causalgia at 3 and 12 months: a randomized comparative trial. Pain 2017; 158(4): 669-81.
[26] Huygen F, Liem L, Cusack W, Kramer J. Stimulation of the L2‐L3 dorsal root ganglia induces effective pain relief in the low back. Pain Pract 2018; 18(2): 205-13.
[27] Weiner RLYA, Yeung A, Montes Garcia C, Tyler Perryman L, Speck B. Treatment of FBSS low back pain with a novel percutaneous DRG wireless stimulator: pilot and feasibility study. Pain Med 2016; 17(10): 1911-6.
[28] Bara GA, Maciaczyk J, Slotty P, Schu S, Vesper J. Dorsal root ganglion stimulation for treatment of phantom limb pain (poster No 420) NANS 2013: Today’s Vision 2013.
[29] Eldabe S, Burger K, Moser H, et al. Dorsal root ganglion (DRG) stimulation in the treatment of phantom limb pain (PLP). Neuromodulation 2015; 18(7): 610-6.
[30] Aiyer R, Barkin RL, Bhatia A, Gungor S. A systematic review on the treatment of phantom limb pain with spinal cord stimulation. Pain Manag 2017; 7(1): 59-69.
[31] Hunter CW, Yang A, Davis T. Selective radiofrequency stimulation of the dorsal root ganglion (DRG) as a method for predicting targets for neuromodulation in patients with post amputation pain: a case series. Neuromodulation 2017; 20(7): 708-18.
[32] Burger K, Moser H, Liem L, Klase D, Eldabe S. Spinal cord stimulation (SCS) of the dorsal root ganglion (DRG) in the treatment of post amputation pain. NANS 2012: From Innovation to Reality, Las Vegas 2012; 145.
[33] Espinet AJ. Stimulation of dorsal root ganglion (DRG) for chronic post‐surgical pain (CPSP): a retrospective single centre case series from Australia using targeted spinal cord stimulation (SCS). Neuromodulation 2015; 18e93
[34] Liem L, Nijhuis H, Huygen F, et al. Treatment of chronic post surgical pain (CPSP) using spinal cord stimulation (SCS) of the dorsal root ganglion (DRG) neurostimulation: results from two prospective studies. Pain Pract 2014; 14: 3-4.
[35] Breel J, Zuidema X, Schapendonk J, Lo B, Wille FF. Treatment of chronic post‐surgical pain with dorsal root ganglion (DRG) stimulation (10701). Neuromodulation 2016; 19e15
[36] Deer TR, Levy RM, Kramer J, et al. Comparison of paresthesia coverage of patient’s Pain: dorsal root ganglion vs. spinal cord stimulation. An ACCURATE study sub-analysis. Neuromodulation 2019; 22(8): 930-6.
[37] Lynch PJ, McJunkin T, Eross E, Gooch S, Maloney J. Case report: successful epiradicular peripheral nerve stimulation of the C2 dorsal root ganglion for postherpetic neuralgia. Neuromodulation 2011; 14(1): 58-61.
[38] Pajuelo A, Papa A, Cormane MA, De Martini L. Retrospective multicenter study using dorsal rootganglion stimulation for postherpetic neuralgia:spanish and italian results. Neuromodulation 2019; 22e330
[39] Deer TR, Mekhail N, Provenzano D, et al. The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee. Neuromodulation 2014; 17(6): 515-50.
[40] Zuidema X, Breel J, Wille F. Paresthesia mapping: a practical workup for successful implantation of the dorsal root ganglion stimulator in refractory groin pain. Neuromodulation 2014; 17(7): 665-9.
[41] Schu S, Gulve A, ElDabe S, et al. Spinal cord stimulation of the dorsal root ganglion for groin pain-a retrospective review. Pain Pract 2015; 15(4): 293-9.
[42] Schu S, Mutagi H, Kapur S, et al. Sustained pain relief in painful diabetic neuropathy (PDN) achieved through targeted spinal cord stimulation (SCS): a retrospective case series. Neuromodulation 2015; 18e91
[43] Eldabe S, Espinet A, Kang P, et al. Dorsal root ganglia stimulation for painful diabetic peripheral neuropathy: a preliminary report. Neuromodulation 2017; 20e51
[44] Falowski S, Pope J, Cusack W. Early US experience with stimulation of the dorsal root ganglia for the treatment of peripheral neuropathy in the lower extremities: a multicenter retrospective case series Abstract from: International Neuromodulation Society - 13th World Congress; 2017.Edinburgh, Scotland, UK.. 2017.
[45] Huygen FJPM, Kallewaard JW, Nijhuis H, et al. Effectiveness and safety of dorsal root ganglion stimulation for the treatment of chronic pain: a pooled analysis. Neuromodulation 2020; 23(2): 213-21.
[46] Harrison C, Epton S, Bojanic S, Green AL, FitzGerald JJ. The efficacy and safety of dorsal root ganglion stimulation as a treatment for neuropathic pain. Neuromodulation 2018; 21(3): 225-33.
[47] Kretzschmar M, Reining M, Schwarz MA. Three-Year outcomes after dorsal root ganglion stimulation in the treatment of neuropathic pain after peripheral nerve injury of upper and lower extremities. Neuromodulation 2020; 2020 E-pub ahead of print
[48] Waszak PM, Modrić M, Paturej A, et al. Spinal cord stimulation in failed Back surgery syndrome: review of clinical use, quality of life and cost-effectiveness. Asian Spine J 2016; 10(6): 1195-204.
[49] De Jaeger M, Goudman L, Brouns R, et al. The long-term response to high-dose spinal cord stimulation in patients with failed back surgery syndrome after conversion from standard spinal cord stimulation: an effectiveness and prediction study. Neuromodulation 2020; ••• E-pub ahead of print
[50] Van Buyten JP, Wille F, Smet I, et al. Therapy-related explants after spinal cord stimulation: results of an international retrospective chart review study. Neuromodulation 2017; 20(7): 642-9.
[51] Rock AK, Truong H, Park YL, Pilitsis JG. Spinal cord stimulation. Neurosurg Clin N Am 2019; 30(2): 169-94.
[52] Taghipour M, Ghaffarpasand F. Antinociceptive effects of spinal cord stimulation by activation of periaqueductal gray matter and rostral ventromedial medulla: a mechanism beyond the gate control theory. Neuromodulation 2018; 21(5): 520-1.
[53] Uno T. Possible mechanisms of spinal cord stimulation: disinhibition of the dorsal horn circuits and ascending nociceptive control. Neuromodulation 2020; 23(3): 407-8.
[54] Mehta V, Bouchareb Y, Ramaswamy S, Ahmad A, Wodehouse T, Haroon A. Metabolic imaging of pain matrix using 18F fluoro-desoxyglucose positron emission tomography/computed tomography for patients undergoing L2 dorsal root ganglion stimulation for low back pain. Neuromodulation 2020; 23(2): 222-33.
[55] Kent AR, Min X, Hogan QH, Kramer JM. Mechanisms of dorsal root ganglion stimulation in pain suppression: a computational modeling analysis. Neuromodulation 2018; 21(3): 234-46.
[56] Parker T, Huang Y, Raghu ALB, FitzGerald JJ, Green AL, Aziz TZ. Dorsal root ganglion stimulation modulates cortical gamma activity in the cognitive dimension of chronic pain. Brain Sci 2020; 10(2): 95.
[57] Koetsier E, Franken G, Debets J, et al. Mechanism of dorsal root ganglion stimulation for pain relief in painful diabetic polyneuropathy is not dependent on GABA release in the dorsal horn of the spinal cord. CNS Neurosci Ther 2020; 26(1): 136-43.
[58] Morgalla MH, de Barros Filho MF, Chander BS, Soekadar SR, Tatagiba M, Lepski G. Neurophysiological effects of dorsal root ganglion stimulation (DRGS) in pain processing at the cortical level. Neuromodulation 2019; 22(1): 36-43.