Thomas M. Kinfe

Chronic Deep Brain Stimulation in Patients with Tardive Dystonia Without a History of Major Psychosis

Tardive dystonia usually occurs with a delay after neuroleptic exposure in patients with major psychosis. A subgroup of patients, however, is given such medication for “mild depression” or “neurasthenia.” Tardive dystonia, in general, may respond favorably to pallidal deep brain stimulation (DBS). Nevertheless, it remains unclear thus far whether or not similar beneficial outcome is achieved with pallidal DBS in different subgroups of patients with tardive dystonia. Four women (mean age 59 years at surgery) underwent stereotactic pallidal DBS in the frame of an observational study. Tardive dystonia occurred secondary to medication with fluspirilene and haloperidol, and injection of long‐acting depot neuroleptics prescribed for mild depression or “nervousness.” Assessment included the Burke‐Fahn‐Marsden (BFM) scale preoperatively and at 12 months follow‐up. Extended follow‐up was available at a mean of 27.3 months postoperatively (range 16–36 months). There were no surgically related complications. All 4 patients experienced sustained statistically significant benefit from pallidal DBS. Mean improvement at 12 months was 77% for the BFM motor score (range, 45–91%; P = 0.043), and 84% at the last available follow‐up (range, 70–91%; P = 0.03). This was paralleled by improvement of the BFM disability score. Chronic pallidal DBS in patients with tardive dystonia without a history of major psychosis provides sustained improvement which is similar to that in other subgroups of patients with tardive dystonia. This effect is stable on extended follow‐up for up to 3 years.

Deep brain stimulation for camptocormia in dystonia and Parkinson's disease

Camptocormia, or “bent spine syndrome”, may occur in various movement disorders such as primary dystonia or idiopathic Parkinson’s disease (PD). Although deep brain stimulation (DBS) is an established treatment in refractory primary dystonia and advanced PD, few data are available on the effect of DBS on camptocormia comparing these two conditions. Seven patients (4 with dystonia, 3 with PD; mean age 60.3xa0years at surgery, range 39–73xa0years) with camptocormia were included in the study. Five patients underwent bilateral GPi DBS and two patients underwent bilateral STN DBS guided by CT-stereotactic surgery and microelectrode recording. Pre- and postoperative motor assessment included the BFM in the dystonia patients and the UPDRS in the PD patients. Severity of camptocormia was assessed by the BFM subscore for the trunk at the last available follow-up at a mean of 17.3xa0months (range 9–36xa0months). There were no surgical complications. In the four patients with dystonia there was a mean improvement of 53% in the BFM motor score (range 41–79%) and of 63% (range 50–67%) in the BFM subscore for the trunk at the last available follow-up (mean 14.3xa0months, range 9–18xa0months). In the three patients with camptocormia in PD who underwent bilateral STN DBS (2 patients) or pallidal DBS (1 patient), the PD symptoms improved markedly (mean improvement in the UPDRS motor subscore stimulation on/medication off 55%, range 49–61%), but there was no or only mild improvement of camptocormia in the two patients who underwent STN DBS, and only moderate improvement in the patient with GPi DBS at the last available follow-up (mean 21xa0months, range 12–36xa0months). GPi DBS is an effective treatment for camptocormia in dystonia. The response of camptocormia to chronic STN or GPi DBS in PD is more heterogenous. The latter may be due to a variety of causes and needs further clarification.

Micrographia induced by pallidal DBS for segmental dystonia: a subtle sign of hypokinesia?

Recently parkinsonism has been reported as a rare side effect of globus pallidus internus (GPi) deep brain stimulation (DBS) for dystonia. In the present systematic prospective study in 11 patients with segmental dystonia not affecting distal arm function, we could demonstrate significant changes in handwriting characterized by mild micrographia following GPi-DBS. We propose that this finding reflects GPi-DBS-induced disturbances of basal ganglia function in terms of a mild hypokinetic syndrome, as a result of outflow alterations in pallido-thalamo-cortical pathways.

High Frequency (10 kHz) or Burst Spinal Cord Stimulation in Failed Back Surgery Syndrome Patients With Predominant Back Pain: Preliminary Data From a Prospective Observational Study.

Conventional spinal cord stimulation (SCS) exhibits pain relief and improved quality of life in refractory failed back surgery syndrome. However, patients suffering from predominant back pain failed to achieve a favorable neuromodulation outcome. Currently, two new stimulation concepts, the burst and the HF10 stimulation paradigms successfully suppress intractable back pain levels in this difficult‐to‐treat subgroup. To date, literature data comparing both stimulation patterns is lacking.

Occipital Nerve Stimulation for Refractory Occipital Pain after Occipitocervical Fusion: Expanding Indications

Background: Occipital nerve stimulation is being used for various pain syndromes. Here, we expand its use for the treatment of refractory occipital pain after occipitocervical fusion. Case Description: We describe a case of occipital neuralgia in a 60-year-old man following posterior occipitocervical fusion. The maximum pain intensity was rated 9/10 on the visual analogue scale (VAS). Since pain proved to be refractory to analgetic medication, two quadripolar electrodes (Resume II, Medtronic) were implanted in the occipital region to stimulate the occipital nerve bilaterally. The patient experienced a dramatic response during test stimulation for 10 days with externalized electrodes, and a pacemaker (Synergy, Medtronic) was connected to the electrodes. While on chronic stimulation (bipolar 6 V, 210 μs, 130 Hz) improvement of pain was maintained, reflected by a decrease in the VAS score to 1/10 at 12 months of follow-up. Conclusion: Occipital nerve stimulation for medical refractory occipital neuralgia after occipitocervical fusion is an effective method expanding the indications for its use.

Less Is More: Adaptation of Voltage after Battery Replacement in Deep Brain Stimulation for Dystonia

Background: To maintain the efficacy of deep brain stimulation (DBS) on dystonic symptoms, slight incremental increase in voltage may be necessary over years after a steady state has been reached following the initial programming of optimal settings. So far however, no data are available regarding the adjustment of voltage after implantable pulse generator (IPG) replacement to achieve sustained optimal control of dystonia with the least side effects. Methods: We analyzed stimulation settings before and after IPG replacement for battery depletion (n = 61) in 18 patients with chronic DBS of the globus pallidus internus or the ventral intermediate nucleus of the thalamus for dystonia. Results: The stimulation intensity could be significantly reduced by 24.8% after IPG replacement. The amount of voltage reduction was equal between bipolar and monopolar stimulation modes (24.9 vs. 24.3%, p = 0.89) and significantly correlated with the magnitude of stimulation intensity before IPG replacement (ρ = 0.429, p = 0.001). Conclusions: After IPG replacement, in patients with DBS for segmental dystonia the voltage can be reduced by approximately 25%. This phenomenon might be explained by a gradual decrease in the electrical energy effectively delivered by the IPG in the course of the lifetime of the battery or neuroplastic processes in particular in the period around battery replacement.

Burst Spinal Cord Stimulation Increases Peripheral Antineuroinflammatory Interleukin 10 Levels in Failed Back Surgery Syndrome Patients With Predominant Back Pain

Burst spinal cord stimulation (SCS) has been reported to reduce back pain and improve functional capacity in Failed Back Surgery Syndrome (FBSS). However, its mechanism of action is not completely understood. Systemic circulating cytokines have been associated with the development of chronic back pain.

Solitary fibrous tumor of the foramen of Monro

Solitary fibrous tumors have been described rarely in the central nervous system and only exceptionally within the ventricular system. This benign entity shows histoimmunochemically strong positivity for vimentin and calretinin. Little is known about the pathophysiological aspects. The authors report on a 75-year-old woman who presented with clinical signs of occlusive hydrocephalus including cognitive deficits, urine incontinence and gait disturbance. Imaging studies demonstrated a tumor at the foramen of Monro which was thought to be a colloid cyst and she underwent CSF shunting. After recurrent episodes of shunt dysfunction the tumor was removed via a transventricular approach guided by endoscopic ventriculoscopy. The histopathological examination revealed a solitary fibrous tumor. This is the first report on a solitary fibrous tumor located at the foramen of Monro in an elderly patient. Surgical removal has been considered to be the best therapeutic strategy in treating this rare entity with no need of postoperative adjuvant therapy. Further imaging and histological studies are needed to improve understanding of the pathophysiological aspects behind it.

Impact of surgical treatment on tremor due to posterior fossa tumors

OBJECTnThe object of this study was to investigate the impact of surgical treatment on tremor caused by posterior fossa tumors.nnnMETHODSnThe authors performed a retrospective evaluation of 6 cases involving patients with tremors due to posterior fossa tumors. Patients who had been treated with neuroleptic medication or had a family history of movement disorders were excluded. All patients had postural or kinetic tremors. Tremor was mainly unilateral. The study group included 5 women and 1 man. Mean age at surgery was 59 years. Five patients underwent total or subtotal tumor resection, and 1 patient underwent stereotactic biopsy only. The histological diagnosis was epidermoid tumor in 2 patients, metastasis in 2 others, and vestibular schwannoma and low-grade glioma in 1 each.nnnRESULTSnTwo patients had no improvement of tremor, postoperatively. In both of these patients the tumor (low-grade glioma in 1, metastasis in the other) involved the dentate nucleus directly. In the other patients, a compressive effect on the dentate nucleus or the dentatothalamic pathways was present without invasion of the cerebellar structures, and immediate or gradual amelioration of the tremor was observed postoperatively.nnnCONCLUSIONSnThe prognosis of tremor due to posterior fossa tumors appears to depend mainly on the involvement of tremor-generating structures. The prognosis appears to be favorable in those patients with compression of these substrates, whereas primary invasion by tumor has a poor prognosis. Caution must be used in generalizing the findings of this study because of the small number of cases in the series.

Burst Spinal Cord Stimulation: Review of Preclinical Studies and Comments on Clinical Outcomes: REVIEW OF BURST SPINAL CORD STIMULATION

Burst spinal cord stimulation (SCS) technology uses a novel waveform that consists of closely packed high‐frequency electrical impulses followed by a quiescent period. Within the growing field of neuromodulation, burst stimulation is unique in that it mimics the natural burst firing of the nervous system, in particular the thalamo‐cingulate rhythmicity, resulting in modulation of the affective and attentional components of pain processing (e.g., medial thalamic pathways).