Switching from constant voltage to constant current in deep brain stimulation: a multicenter experience of mixed implants for movement disorders.

BACKGROUND AND PURPOSE: For many years deep brain stimulation (DBS) devices relied only on voltage-controlled stimulation (CV), but recently current-controlled devices have been developed and approved for new implants as well as for replacement of CV devices after battery drain. Constant-current (CC) stimulation has been demonstrated to be effective in new implanted parkinsonian and dystonic patients, but the effect of switching to CC therapy in patients chronically stimulated with CV implantable pulse generators (IPGs) has not been assessed. This report shows the results of a consecutive retrospective data collection performed at five Italian centers before and after replacement of constant-voltage with constant-current DBS devices, in order to verify the clinical efficacy and safety of this procedure. METHODS: Nineteen patients with Parkinson's disease or dystonic syndrome underwent DBS IPG CV/CC replacement. Clinical features and therapy satisfaction were assessed before surgery, 1 week after and 3 and 6 months after replacement. Programming settings and impedances were recorded before removing the CV device and when the CC IPGs were switched on. RESULTS: The clinical outcome of CC stimulation was similar to that obtained with CV devices and remained stable at 3 and 6 months of follow-up. Impedance values recorded for CV and CC IPGs were similar. Ninety-five percent of patients and physicians were satisfied with mixed implants. No adverse events occurred after IPG replacement. CONCLUSION: Replacing CV with CC IPGs is a safe and effective procedure. Longer follow-up is necessary to better clarify the impact of CC stimulation on clinical outcome after chronic stimulation in CV mode.

Two-year follow-up after microsurgical discectomy and dynamic percutaneous stabilization in degenerate and herniated lumbar disc: clinical and neuroradiological outcome.

AIM: Lumbar disc herniation associated with back pain is often related to disc degeneration. Back pain after microdiscectomy often persists, prejudicing clinical outcome and quality of life. To this day, the evolution of disc degeneration after classical microdiscectomy has never been proven. Percutaneous dynamic stabilization after microdiscectomy has been proposed as a novel surgical strategy for treatment of back pain with herniated disc. However, clinical results are still debated and no evidences about the long-term evolution of back pain and relationships between neuroradiological imaging and clinical outcome have been provided. We report our preliminary observations concerning the clinical and neuroradiological outcome of 11 patients treated with microdiscectomy and dynamic percutaneous lumbo-sacral stabilization, after a long-term follow-up (2-years). METHODS: This was an uncontrolled case series. The study included 11 patients (3 F, 8 M) with L5-S1 discal herniation and degeneration underwent microdiscectomy and percutaneous dynamic stabilization, from December 2008 to November 2009. All the patients were symptomatic with back and leg pain non-responsive to long-term (8-12 months) medical and physical treatments. VAS and Satisfaction Index were used, respectively, for evaluation of clinical outcome and general postoperative patients' satisfaction. Modic and Pfirrmann scores were used for evaluation of neuroradiological outcome. All the patients underwent to microdiscectomy and implantation of the same percutaneous device for dynamic stabilization of the middle vertebral column during the same surgery. Modic, Pfirrmann, VAS and Satisfaction Index scores were collected before surgery and over the follow-up (45 days, 1 and 2 years). MRI and dynamic X-Ray 2 years after surgery were compared to the preoperative imaging. RESULTS: Motion preservation at the functional spinal unit after surgery was demonstrated in all the cases. All patients reported a reduction or complete resolution of back and leg pain, they were satisfied and came back to normal socio-professional life. No modification of the preoperative Pfirrmann was observed, even in those patients who experienced restoration of back pain. No surgical complications nor device failures were reported. CONCLUSION: Percutaneous minimally invasive lumbo-sacral dynamic stabilization after microdiscectomy seems a reliable and effective technique in order to obtain a resolution of back pain and seems to prevent the Pfirrmann worsening, over a long-term follow-up.

Five-year follow-up of 10 patients treated with globus pallidus internus deep brain stimulation for segmental or multisegmental dystonia.

INTRODUCTION: Globus pallidus internus (GPi) deep brain stimulation (DBS) represents a validated, effective, and safe treatment for patients affected by generalized dystonia resistant to conservative treatment. Segmental and multisegmental dystonia have more recently been proposed as further indications for GPi DBS despite the lack of long-term homogenous follow-up. Here we present an original and detailed long-term follow-up (5 years) of a homogeneous population of 11 patients affected by segmental or multisegmental dystonia. MATERIALS AND METHODS: Ten patients underwent bilateral GPi DBS electrode implantations under a Leksell stereotactic guide, with intraoperative neurophysiological monitoring. The follow-ups at 1, 3 and 5 years were collected using video-BFMDRS for motor and disability scores. The statistical analysis of the results is provided. RESULTS: We reported a statistically significant improvement in motor and disability overall scores until 5 years after treatment. At the last follow-up, even the single motor subitems were statistically improved. DISCUSSION: We observed a continuous and statistically significant improvement in all of the motor subitems and in the overall disability score until the 3-year follow-up. These results did not improve any further but they appeared steady at the last follow-up. We also report a significant improvement in the cranial-cervical subitems. CONCLUSIONS: GPi DBS should definitely be considered a safe and effective treatment also for segmental and multisegmental dystonia even in cases of relevant or prevalent cranial-cervical involvement.

Spinal anesthesia and minimal invasive laminotomy for paddle electrode placement in spinal cord stimulation: technical report and clinical results at long-term followup.

OBJECT: We arranged a mini-invasive surgical approach for implantation of paddle electrodes for SCS under spinal anesthesia obtaining the best paddle electrode placement and minimizing patients' discomfort. We describe our technique supported by neurophysiological intraoperative monitoring and clinical results. METHODS: 16 patients, affected by neuropathic pain underwent the implantation of paddle electrodes for spinal cord stimulation in lateral decubitus under spinal anesthesia. The paddle was introduced after flavectomy and each patient confirmed the correct distribution of paresthesias induced by intraoperative test stimulation. VAS and patients' satisfaction rate were recorded during the followup and compared to preoperative values. RESULTS: No patients reported discomfort during the procedure. In all cases, paresthesias coverage of the total painful region was achieved, allowing the best final electrode positioning. At the last followup (mean 36.7 months), 87.5% of the implanted patients had a good rate of satisfaction with a mean VAS score improvement of 70.5%. CONCLUSIONS: Spinal cord stimulation under spinal anesthesia allows an optimal positioning of the paddle electrodes without any discomfort for patients or neurosurgeons. The best intraoperative positioning allows a better postoperative control of pain, avoiding the risk of blind placements of the paddle or further surgery for their replacement.

Awake surgery in low-grade gliomas harboring eloquent areas: 3-year mean follow-up.

Low-grade gliomas are slow-growing tumors invading eloquent areas and white matter pathways. For many decades these tumors were considered inoperable because of their high tropism for eloquent areas. However, the young age of the patients and the inescapable anaplastic transformation have recently suggested more aggressive treatments. We analyzed the neurological and neuro-oncological outcome of 12 patients who underwent surgery fully awake for the resection of LGG, harboring eloquent areas. 10 right- and 2 left-handed patients underwent pre-operative assessment: Karnofsky Performance Status, Edinburgh Handedness Inventory Score; neuropsychological and neurophysiological evaluations, according to the tumor location. During surgery we performed: sensory-motor-evoked potentials, continuous electro-corticography and bipolar/monopolar cortico-subcortical mapping during neuropsychological tests. The resection rate was calculated with neuro-imaging elaboration software. No permanent post-operative deficits were reported; 2 patients improved after surgery. No impairment of cognitive functions was reported. The KPS improved in 8 patients and was steady in the others. The mean resection rate was 78.3%. The resection allowed the control of pre-operative seizures without increasing the drug intake. Awake surgery allowed a good resection rate despite the eloquent location of the tumors, without post-operative deficit. The neuropsychological outcome was unchanged after surgery. The resection seems to improve seizure control. All the patients came back to normal life and work. In conclusion, awake surgery is reliable and feasible in removal of LGG, even if invading the main eloquent areas and networks. All the patients experienced a normal life after surgery, without permanent deficits.