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Objective We present long-term follow-up results and analysis of stimulation sites of a prospective cohort study of six patients with chronic cluster headaches undergoing deep brain stimulation of the ipsilateral posterior hypothalamic region. Methods The primary endpoint was the postoperative change in the composite headache severity score “headache load” after 12 months of chronic stimulation. Secondary endpoints were the changes in headache attack frequency, headache attack duration and headache intensity, quality of life measures at 12, 24, and 48 months following surgery. Stimulating contact positions were analysed and projected onto the steroetactic atlas of Schaltenbrand and Wahren. Results There was a significant reduction of headache load of over 93% on average at 12 months postoperatively that persisted over the follow-up period of 48 months ( p = 0.0041) and that was accompanied by a significant increase of reported quality of life measures ( p = 0.03). Anatomical analysis revealed that individual stimulating electrodes were located in the red nucleus, posterior hypothalamic region, mesencephalic pretectal area and centromedian nucleus of the thalamus. Conclusions Our findings confirming long-term effectiveness of deep brain stimulation for chronic cluster headaches suggest that the neuroanatomical substrate of deep brain stimulation-induced headache relief is probably not restricted to the posterior hypothalamic area but encompasses a more widespread area.

Deep brain stimulation (DBS) of the anterior cingulate cortex (ACC) is a recent technique that has shown some promising short-term results in patients with chronic refractory neuropathic pain. Three years after the first case series, we assessed its efficacy on a larger cohort, with longer follow-up.Twenty-four patients (19 males; average age, 49.1 years) with neuropathic pain underwent bilateral ACC DBS. Patient-reported outcome measures were collected before and after surgery, using the Numerical Rating Scale (NRS), Short-Form 36 quality of life (SF-36), McGill Pain Questionnaire (MPQ), and EuroQol 5-domain quality of life (EQ-5D) questionnaire.Twenty-two patients after a trial week were fully internalized and 12 had a mean follow-up of 38.9 months. Six months after surgery the mean NRS score decreased from 8.0 to 4.27 (P = 0.004). There was a significant improvement in the MPQ (mean, -36%; P = 0.021) and EQ-5D score significantly decreased (mean, -21%; P = 0.036). The physical functioning domain of SF-36 was significantly improved (mean, +54.2%; P = 0.01). Furthermore, in 83% of these patients, at 6 months, NRS score was improved by 60% (P < 0.001) and MPQ decreased by 47% (P < 0.01). After 1 year, NRS score decreased by 43% (P < 0.01), EQ-5D was significantly reduced (mean, -30.8; P = 0.05) and significant improvements were also observed for different domains of the SF-36. At longer follow-ups, efficacy was sustained up to 42 months in some patients, with an NRS score as low as 3.Follow-up results confirm that ACC DBS alleviates chronic neuropathic pain refractory to pharmacotherapy and improves quality of life in many patients.

Objective To quantify the relationship between the electrical power requirement to achieve pain relief and the position of the active electrode of dorsal root ganglion stimulators within the spinal nerve root exit foramen. Materials and Methods Retrospective analysis of prospectively collected data of 92 consecutive patients undergoing dorsal root ganglion stimulation (DRGS) for chronic pain in a single center. Cervical and sacral cases, and failed trials/explanted DRGS were excluded, so we report on 57 patients with 78 implanted leads. Anteroposterior and lateral fluoroscopic images of the lead in the exit foramen were examined, and the active electrode positions were put into categories depending on their location relative to fixed anatomical landmarks. The clinical outcome and the power requirements for each of these groups of electrodes were then analyzed. Overall pain outcome was assessed by numeric pain rating scale score pre‐operatively and post‐operatively. Results There was no significant relationship between power requirements and mediolateral electrode position, although the lowest average was observed with electrode positions directly below the center of the pedicle. On lateral x‐ray, the lowest power requirements were observed in the electrodes positioned superodorsally or dorsally within the foramen. Importantly, power requirements in this location were consistently low, while the power requirements in other locations were not only higher but also much more variable. Electrodes in the superodorsal position required a median output power almost four times lower than electrodes in other positions (p = 0.002). Clinical outcome was not significantly related to power requirement or foraminal position. Conclusion Aiming for a superodorsal electrode position on lateral intraoperative fluoroscopy is desirable, since siting leads in this location reduces the required stimulator output power very substantially and thus will extend battery life. Position within the foramen does not determine clinical outcome, and so the implanter can safely aim for the low power site without detriment to the analgesic efficacy of the system.

Background Trigeminal Neuropathic Pain (TNP) is a chronic facial pain syndrome caused by a lesion or disease affecting one or more branches of the trigeminal nerve. It may, for example, result from accidental injury to a branch of the trigeminal nerve by trauma or during surgery; it may also be idiopathic. TNP is typically constant, in contrast to most cases of the commoner trigeminal neuralgia. In some cases, pain may be refractory to pharmacological treatment. Peripheral nerve field stimulation is recognized as an effective minimally invasive surgical treatment option for this debilitating condition. To date, stimulation has used conventional tonic waveforms, which generate paraesthesia in the stimulated area. This is the first report of the use of paraesthesia‐free burst pattern stimulation for TNP. Methods Seven patients were treated at the John Radcliffe Hospital for TNP from 2016 to 2018. Mean duration of preoperative symptoms was five years. All patients had exhausted pharmacological measures to limited effect. The initial three patients had tonic stimulation with the subsequent four having burst stimulation. Outcome was assessed using the numeric pain rating scale preoperatively and postoperatively at three and six months and one year. Side‐effects and complications were also assessed as well as reduction in analgesic medication use. Results All patients achieved pain reduction of at least 50% at 6 months (range 50–100%, mean 81%, p = 0.0082). Those in the burst stimulation group were paraesthesia free. One patient developed a postoperative infection for which the system had to be removed and is awaiting reimplantation. There were no other complications in either group. Conclusion Burst stimulation conferred similar pain control to tonic stimulation in our small cohort, and there were similar reductions in pain medication use. An additional benefit of burst stimulation is freedom from paraesthesia. Larger scale studies are needed to further evaluate burst stimulation and compare its efficacy with that of tonic stimulation.

BACKGROUND: Occipital nerve stimulation (ONS) is widely used for headache syndromes including chronic migraine (CM) and chronic cluster headache (CCH). The paraesthesia associated with tonic stimulation can be bothersome and can limit therapy. It is now clear in spinal cord stimulation that paraesthesia-free waveforms can produce effective analgesia, but this has not been reported in ONS for CM or CCH. MATERIALS AND METHODS: seventeen patients (12 CM and 5 CCH) were treated with bilateral burst pattern ONS, including 4 who had previously had tonic ONS. Results were assessed in terms of the frequency of headaches (number of headache days per month for CM, and number of attacks per day for CCH) and their intensity on the numeric pain rating scale. RESULTS: Burst ONS produced a statistically significant mean reduction of 10.2 headache days per month in CM. In CCH, there were significant mean reductions in headache frequency (92%) and intensity (42%). CONCLUSION: Paraesthesia is not necessary for good quality analgesia in ONS. Larger studies will be required to determine whether the efficacies of the two stimulation modes differ. Burst ONS is imperceptible and therefore potentially amenable to robustly blinded clinical trials.

Deep brain stimulation (DBS) has shown promise for relieving nociceptive and neuropathic symptoms of refractory chronic pain. We assessed the efficacy of a new target for the affective component of pain, the anterior cingulate cortex (ACC). A 49-year-old man with neuropathic pain underwent bilateral ACC DBS. Patient-reported outcome measures were collected before and 2 years after surgery using a Visual Analogue Scale, Short-Form 36 quality of life survey, McGill pain questionnaire, EuroQol-5D questionnaires (EQ-5D; Health State) and neuropsychological assessments. The patient improved with DBS. Two years after surgery, the Visual Analogue Scale decreased from 6.7 to 3.0, McGill pain questionnaire improved by 42% and EQ-5D Health State increased by 150%. Stimulating the ACC at 130 Hz, 330 µs and 3 V facilitated neuropathic pain relief. The DBS remained efficacious during the 2-year follow-up period. Affective ACC DBS can relieve chronic neuropathic pain refractory to pharmacotherapy and restore quality of life.

Objectives: To assess the effect of peripheral nerve stimulation on neuropathic testicular pain. Material and Methods: A 30-year-old man with a four-year history of chronic testicular pain following scrotal hydrocele surgery had two percutaneous leads implanted in his groin and low-frequency stimulation of the cutaneous branch of the ilioinguinal and genital branch of the genitofemoral nerves. Result: At seven-month follow-up, the pain intensity had declined from 9/10 to 2/10 on the numeric rating scale. Conclusion: We report the successful implantation of an ilioinguinal and genitofemoral nerve stimulator for sustained suppression of intractable neuropathic testicular pain.

We present the long-term course of motor cortex stimulation to relieve a case of severe burning phantom arm pain after brachial plexus injury and amputation. During 16-year follow-up the device continued to provide efficacious analgesia. However, several adjustments of stimulation parameters were required, as were multiple pulse generator changes, antibiotics for infection and one electrode revision due to lead migration. Steady increases in stimulation parameters over time were required. One of the longest follow-ups of motor cortex stimulation is described; the case illustrates challenges and pitfalls in neuromodulation for chronic pain, demonstrating strategies for maintaining analgesia and overcoming tolerance.

Background Deep brain stimulation (DBS) of the anterior cingulate cortex (ACC) is a new treatment for alleviating intractable neuropathic pain. However, it fails to help some patients. The large size of the ACC and the intersubject variability make it difficult to determine the optimal site to position DBS electrodes. The aim of this work was therefore to compare the ACC connectivity of patients with successful versus unsuccessful DBS outcomes to help guide future electrode placement. Methods Diffusion magnetic resonance imaging (dMRI) and probabilistic tractography were performed preoperatively in 8 chronic pain patients (age 53.4 ± 6.1 years, 2 females) with ACC DBS, of whom 6 had successful (SO) and 2 unsuccessful outcomes (UOs) during a period of trialing. Results The number of patients was too small to demonstrate any statistically significant differences. Nevertheless, we observed differences between patients with successful and unsuccessful outcomes in the fiber tract projections emanating from the volume of activated tissue around the electrodes. A strong connectivity to the precuneus area seems to predict unsuccessful outcomes in our patients (UO: 160n/SO: 27n), with ( n ), the number of streamlines per nonzero voxel. On the other hand, connectivity to the thalamus and brainstem through the medial forebrain bundle (MFB) was only observed in SO patients. Conclusions These findings could help improve presurgical planning by optimizing electrode placement, to selectively target the tracts that help to relieve patients' pain and to avoid those leading to unwanted effects.

The authors report the first case of successful implantation of a dorsal root ganglion stimulator at L1 and L2 for sustained improvement in chronic pelvic girdle pain.

BACKGROUND:: Deep brain stimulation (DBS) has shown considerable promise for relieving nociceptive and neuropathic symptoms of refractory chronic pain. Nevertheless, for some patients, standard DBS for pain remains poorly efficacious. Pain is a multi-dimensional experience with an affective component: the unpleasantness. The anterior cingulate cortex (ACC) is a structure involved in this affective component and targeting it may relieve patients.OBJECTIVE:: To describe the first case series of ACC DBS to relieve the affective component of chronic neuropathic pain.METHODS:: 16 patients (13 males and 3 females) with neuropathic pain underwent bilateral ACC DBS. Mean age at surgery was 48.7 [33-63] years. Patient reported outcome measures were collected before and after surgery, using a Visual Analogue Scale (VAS), Short Form 36 quality of life survey (SF-36), McGill pain questionnaire (MPQ) and EuroQol-5D questionnaires (EQ-5D; Health state).RESULTS:: 15 patients (93.3 %) transitioned from externalized to fully internalized systems. 11 patients had data to be analyzed with a mean follow-up of 13.2 months. Post-surgery, VAS dropped below 4 for 5 of the patients, with one patient freed from pain. Highly significant improvement of EQ-5D was observed (mean +20.3%, range +0% to +83%, p=0.008). Moreover, statistically significant improvements were observed for the PF (physical functioning) and BP (bodily pain) domains of the SF-36 quality of life survey: mean +64.7% (range -8.9% to +276%, p=0.015) and mean +39.0% (range -33.8% to +159%, p=0.050), respectively.CONCLUSION:: Affective ACC DBS can relieve chronic neuropathic pain refractory to pharmacotherapy and restore quality of life.

In October 2008 the National Institute for Health and Clinical Excellence issued guidance supporting the use of spinal cord stimulation for people with chronic neuropathic pain, considering it to be a cost-effective use of resources within the NHS. This paper will provide an overview of chronic neuropathic pain. Spinal cord stimulation (SCS) will be explained, including the physiological mechanism and technology behind this treatment. The recent NICE guidance will be discussed along with information relating to the potential impact the guidance will have on Primary Care Trusts, GPs and community practitioners. A guide is provided for clinicians in primary care regarding access to this treatment and routes for referral.

BACKGROUND: Deep brain stimulation (DBS) to treat neuropathic pain refractory to pharmacotherapy has reported variable outcomes and has gained United Kingdom but not USA regulatory approval. OBJECTIVE: To prospectively assess long-term efficacy of DBS for chronic neuropathic pain in a single-center case series. METHODS: Patient reported outcome measures were collated before and after surgery, using a visual analog score, short-form 36-question quality-of-life survey, McGill pain questionnaire, and EuroQol-5D questionnaires (EQ-5D and health state). RESULTS: One hundred ninety-seven patients were referred over 12 years, of whom 85 received DBS for various etiologies: 9 amputees, 7 brachial plexus injuries, 31 after stroke, 13 with spinal pathology, 15 with head and face pain, and 10 miscellaneous. Mean age at surgery was 52 years, and mean follow-up was 19.6 months. Contralateral DBS targeted the periventricular gray area (n = 33), the ventral posterior nuclei of the thalamus (n = 15), or both targets (n = 37). Almost 70% (69.4%) of patients retained implants 6 months after surgery. Thirty-nine of 59 (66%) of those implanted gained benefit and efficacy varied by etiology, improving outcomes in 89% after amputation and 70% after stroke. In this cohort, >30% improvements sustained in visual analog score, McGill pain questionnaire, short-form 36-question quality-of-life survey, and EuroQol-5D questionnaire were observed in 15 patients with >42 months of follow-up, with several outcome measures improving from those assessed at 1 year. CONCLUSION: DBS for pain has long-term efficacy for select etiologies. Clinical trials retaining patients in long-term follow-up are desirable to confirm findings from prospectively assessed case series.

Following a total of 386 deep brain stimulation (DBS) procedures in Oxford, only two seizures have been recorded in the peri-operative period. Both patients had MS and underwent thalamic DBS for tremor and these 2 cases are presented here. The incidence of peri-operative seizures in MS patients undergoing DBS procedures is more than 8-fold greater than that expected for patients undergoing DBS procedures. Further experience with DBS procedures in MS patients is needed to determine whether there is a role for peri-operative anticonvulsants in these patients.

Publisher Summary This chapter focuses on the utility of deep brain stimulation (DBS) for treating pain. DBS is a neurosurgical intervention whose safety, efficacy, and utility have been robustly demonstrated in movement disorders. Current results suggest that DBS gives analgesia most consistently to patients with pain after stroke, amputation (either phantom or stump) and anesthesia dolorosa. DBS can be trailed instead of SCS or MCS in carefully selected patients wherever the etiologies of chronic pain are consistent with neuronal reorganization at multiple levels of the central neuromatrix. Preference in patient selection is determined after multidisciplinary assessment demonstrating quantitatively severe pain refractory to medication for at least one year with significantly impaired quality of life and likely neuropathic etiology with unlikely spinal involvement. Medical contraindications to DBS include uncorrectable coagulopathy obviating neurosurgery and ventriculomegaly sufficient to preclude direct electrode passage to the surgical target. Complete pain eradication by DBS may accompany unease, motor complications, or other sequelae precipitating intolerance of stimulation. Thus, investigators should endeavor to include quality of life measures in outcome assessment to overcome the limitations of using pain questionnaires alone. And it should only be performed in experienced and specialist centers which are willing to carefully study their patients and publish their results.

The aim of this study was to determine the efficacy of deep brain stimulation (DBS) in the treatment of various types of intractable head and facial pains. Seven patients underwent the insertion of DBS electrodes into the periventricular/periaqueductal grey region and/or the ventroposteromedial nucleus of the thalamus. We have shown statistically significant improvement in pain scores (visual analogue and McGill's) as well as health-related quality of life (SF-36v2) following surgery. There is wide variability in patient outcomes but, overall, DBS can be an effective treatment. Our results are compared with the published literature and electrode position for effective analgesia is discussed.