Deep Brain Stimulation Improves the Symptoms and Sensory Signs of Persistent Central Neuropathic Pain from Spinal Cord Injury: A Case Report

Central neuropathic pain (CNP) is a significant problem after spinal cord injury (SCI). Pharmacological and non-pharmacological approaches may reduce the severity, but relief is rarely substantial. While deep brain stimulation (DBS) has been used to treat various chronic pain types, the technique has rarely been used to attenuate CNP after SCI. Here we present the case of a 54-year-old female with incomplete paraplegia who had severe CNP in the lower limbs and buttock areas since her injury 30 years prior. She was treated with bilateral DBS of the midbrain periaqueductal gray (PAG). The effects of this stimulation on CNP characteristics, severity and pain-related sensory function were evaluated using the International SCI Pain Basic Data Set (ISCIPBDS), Neuropathic Pain Symptom Inventory (NPSI), Multidimensional Pain Inventory and Quantitative Sensory Testing before and periodically after initiation of DBS. After starting DBS treatment, weekly CNP severity ratings rapidly decreased from severe to minimal, paralleled by a substantial reduction in size of the painful area, reduced pain impact and reversal of pain-related neurological abnormalities, i.e., dynamic-mechanical and cold allodynia. She discontinued pain medication on study week 24. The improvement has been consistent. The present study expands on previous findings by providing in-depth assessments of symptoms and signs associated with CNP. The results of this study suggest that activation of endogenous pain inhibitory systems linked to the PAG can eliminate CNP in some people with SCI. More research is needed to better-select appropriate candidates for this type of therapy. We discuss the implications of these findings for understanding the brainstem’s control of chronic pain and for future progress in using analgesic DBS in the central gray

Brain-Computer interface control of stepping from invasive electrocorticography upper-limb motor imagery in a patient with quadriplegia

Introduction: Most spinal cord injuries (SCI) result in lower extremities paralysis, thus diminishing ambulation. Using brain-computer interfaces (BCI), patients may regain leg control using neural signals that actuate assistive devices. Here, we present a case of a subject with cervical SCI with an implanted electrocorticography (ECoG) device and determined whether the system is capable of motor-imagery-initiated walking in an assistive ambulator.Methods: A 24-year-old male subject with cervical SCI (C5 ASIA A) was implanted before the study with an ECoG sensing device over the sensorimotor hand region of the brain. The subject used motor-imagery (MI) to train decoders to classify sensorimotor rhythms. Fifteen sessions of closed-loop trials followed in which the subject ambulated for one hour on a robotic-assisted weight-supported treadmill one to three times per week. We evaluated the stability of the best-performing decoder over time to initiate walking on the treadmill by decoding upper-limb (UL) MI.Results: An online bagged trees classifier performed best with an accuracy of 84.15% averaged across 9 weeks. Decoder accuracy remained stable following throughout closed-loop data collection.Discussion: These results demonstrate that decoding UL MI is a feasible control signal for use in lower-limb motor control. Invasive BCI systems designed for upper-extremity motor control can be extended for controlling systems beyond upper extremity control alone. Importantly, the decoders used were able to use the invasive signal over several weeks to accurately classify MI from the invasive signal. More work is needed to determine the long-term consequence between UL MI and the resulting lower-limb control

Mathematical Equation for Precise Burr Hole Placement in Stereotactic Deep Brain Stimulation Lead Placement

Abstract Frame-based stereotactic lead placement for deep brain stimulation requires a carefully planned trajectory and approach. Point of entry at the cortex is usually selected to be over a gyrus avoiding veins. The angle of lead entry into the skull is different from the perpendicular direction of the burr drill. If the burr hole is not placed properly, the inner plate of the skull may be in the way of the lead, which creates a snowball effect of complications from trajectory readjustment to improperly fitting hardware. Using trigonometric principles, we elucidated a mathematical equation that predicts the precise position of the burr hole in order for the lead to enter exactly in the middle of the opening

Comparative effects of unilateral and bilateral subthalamic nucleus deep brain stimulation on gait kinematics in Parkinson's disease: a randomized, blinded study

Gait dysfunction in Parkinson's disease (PD) does not always respond to bilateral subthalamic nucleus deep brain stimulation (STN-DBS). Since right hemisphere motor networks may be dominant for gait control, identical stimulation of asymmetric circuits could account for gait dysfunction. We compared the effects of bilateral and unilateral STN-DBS on gait kinematics in PD patients who developed gait impairment after STN-DBS. Twenty-two PD patients with >50 % improvement in motor scores, but dopamine-resistant gait dysfunction 6-12 months after bilateral STN-DBS were blindly tested off dopaminergic effects in four randomly assigned DBS conditions: bilateral, right-sided, left-sided and off stimulation. Motor scores (MDS-UPDRS III), gait scores (MDS-UPRDS 2.11-2.13 + 3.9-3.13), turning time (seconds), stride length (meters) and velocity (meters/second) were measured 1 h after DBS changes. Motor and gait scores significantly improved with bilateral versus unilateral STN-DBS. Stride length and velocity (0.95 ± 0.06, 0.84 ± 0.07) significantly improved with bilateral (1.09 ± 0.04, 0.95 ± 0.05), right-sided (1.06 ± 0.04, 0.92 ± 0.05) and left-sided stimulation (1.01 ± 0.05, 0.90 ± 0.05) (p < 0.05). Stride length significantly improved with right-sided versus left-sided (0.05 ± 0.02) and bilateral versus left-sided stimulation (0.07 ± 0.02) (p < 0.05). Turning time (4.89 ± 0.6) tended to improve with bilateral (4.13 ± 0.5) (p = 0.15) and right-sided (4.27 ± 0.6) (p = 0.2) more than with left STN-DBS (4.69 ± 0.5) (p = 0.5). Bilateral STN-DBS yields greater improvement in motor and gait scores in PD patients. Yet, unilateral stimulation has similar effects on gait kinematics. Particularly, right-sided stimulation might produce slightly greater improvements. Although the clinical relevance of differential programming of right versus left-sided STN-DBS is unclear, this approach could be considered in the management of treatment-resistant gait dysfunction in PD

Accuracy of frame-based and frameless systems for deep brain stimulation: A meta-analysis

Deep brain stimulation (DBS) is an effective treatment for movement disorders. It relies on the accurate placement of leads within small nuclei in the basal ganglia. Traditionally, this has been done with great success using frame-based stereotaxy. More recently, frameless systems have been introduced, and several studies have investigated whether they can achieve a similar accuracy. The objective of this meta-analysis was to assess the difference in targeting accuracy between frameless and frame-based systems in deep brain stimulation, using prior studies reporting error in all cardinal directions. We recorded the mean error and standard deviation, and calculated the composite mean difference in error between frame-based and frameless methods using standard difference of means. A total of 76 papers were screened, 25 papers were further assessed, and 5 papers were included in the meta-analysis for a total of 425 DBS electrode placements evaluated. Standard difference of means analysis revealed a statistically significant benefit to frame-based stereotaxy for the x and y coordinates with p = 0.036 and p = 0.0025, respectively. There was no significant difference in the z coordinate. However, the mean differences between frame-based and frameless stereotaxy was small and the composite mean differences were found to be 0.3037 mm, 0.0305 mm, and 0.1630 mm in the x, y and z direction. Our analysis shows that frameless systems represent a reasonable alternative to frame-based methods. Though there was a statistically significant loss of accuracy with frameless methods, the size of this effect was very small and of questionable clinical significance

215 Laser Thermal Ablation for Mesiotemporal Epilepsy: Relation of Ablation Cavities to Seizure and Neurocognitive Outcomes

Abstract INTRODUCTION Laser interstitial thermal therapy (LiTT) has dramatically changed the management of mesiotemporal epilepsy (mTLE) in recent years. The goal of this study was to identify features of ablations and trajectories that correlate with optimal seizure control and minimize the risk of neurocognitive deficits in patients undergoing LiTT for mTLE. METHODS Clinical and radiographic data were reviewed from a prospectively maintained database of patients undergoing LiTT for epilepsy at the University of Miami. Standard preoperative and postoperative evaluations, including contrast-enhanced MRI and neurocognitive testing, were performed in all patients. Laser trajectory and ablation volumes were computed both by manual tracing of mesiotemporal structures and by nonrigid registration of ablation cavities to a common reference system based on 7T MRI data. RESULTS >Of the 28 patients with at least 1-year follow-up, sparing of the mesial hippocampal head was significantly correlated with persistent disabling seizures (P = 0.01). Projecting all ablation cavities onto a common reference frame showed a clear tendency towards lateral placement of the laser with inadequate mesial hippocampal head ablation in these patients compared to those free of seizures. Patients that suffered deficits in memory, on the other hand, tended to have larger ablations with greater insult to entorrhinal and perirhinal cortex than those free of memory deficits. CONCLUSION Better understanding of the impact of ablation volume and location through the use of image normalization tools could potentially fine-tune this novel technique to improve seizure-freedom rates and associated neurocognitive deficits

Acute symptomatic peri-lead edema 33 hours after deep brain stimulation surgery: a case report

Abstract Background Symptomatic peri-lead edema is a rare complication of deep brain stimulation that has been reported to develop 4 to 120 days postoperatively. Case presentation Here we report the case of a 63-year-old Hispanic man with an 8-year history of Parkinson’s disease who underwent bilateral placement of subthalamic nucleus deep brain stimulation leads and presented with acute, symptomatic, unilateral, peri-lead edema just 33 hours after surgery. Conclusions We document a thorough radiographic time course showing the evolution of these peri-lead changes and their regression with steroid therapy, and discuss the therapeutic implications of these findings. We propose that the unilateral peri-lead edema after bilateral deep brain stimulation is the result of severe microtrauma with blood–brain barrier disruption. Knowledge of such early manifestation of peri-lead edema after deep brain stimulation is critical for ruling out stroke and infection and preventing unnecessary diagnostic testing or hardware removal in this rare patient population

Unique Clinical Presentation of Pediatric Shunt Malfunction

Introduction: A cerebrospinal fluid (CSF) shunt is the primary treatment for most etiologies of hydrocephalus in the pediatric population. Malfunction of the shunt may present with unique symptoms and signs. This retrospective review investigates the presenting signs and symptoms of pediatric patients with shunt malfunction. Clinical Material and Method: One-hundred-and-thirty CSF diversion procedures were performed at two affiliated pediatric hospitals over a 2-year period. Seventy consecutive cases of CSF shunt revision were reviewed. These 70 operations were performed on 65 patients. Their medical records and radiographic studies were reviewed, and supplemented with a telephone interview to obtain a minimum of 3 months follow-up. Results: The 65 patients’ age ranged from 3 months to 16 years. The original etiology of the hydrocephalus was Chiari II malformation in 17, idiopathic in 15 and intraventricular hemorrhage in 10, neoplasm in 8 patients and meningitis in 5 patients. The most frequent presenting symptoms were headache (39 admissions), nausea/vomiting (28) and drowsiness (21). Seven Chiari patients (41%) presented with neck pain, 2 (12%) presented with lower cranial nerve palsy, and 2 (12%) presented with symptomatic syrinx, complaints not reported by non-Chiari patients (p < 0.01, χ2 analysis). Four myelodysplastic patients presented with a new-onset or recurrent seizure episode, which was significantly more frequent than in nonmyelodysplastic patients (p < 0.05, χ2 analysis). On examination, increased head circumference was noted in 17 patients. Parinaud’s syndrome was noted more prominently in patients with a history of intracranial neoplasm (4 of 8 cases) than in patients with nonneoplastic diseases (2 of 62 cases; p < 0.05, χ2 analysis). Other interesting presenting signs were pseudocyst (2), syringomyelia (2), hemiparesis (2) and Parkinson-like rigidity (2). Conclusion: Pediatric shunt malfunction generally presents with headache, nausea/vomiting, altered mental status, increased head circumference and bulging fontanelle. Other less frequent but unique presenting signs and symptoms, such as neck pain, syringomyelia and lower cranial nerve palsy in the myelodysplastic population, and Parinaud’s syndrome in patients with a history of intracranial neoplasm are frequently associated with shunt malfunction and should prompt a radiographic workup

Treatment of Pain and Autonomic Dysreflexia in Spinal Cord Injury with Deep Brain Stimulation

This project is a study of electrical deep brain stimulation as a method for treating pain and autonomic dysreflexia in patients with chronic spinal cord injury. It is collaboration between the University of Miami and the Miami Veterans Administration Hospital. The first year was mainly taken up with obtaining regulatory approval. In the second year and third year (report year), four subjects were enrolled, with one later withdrawing. Best pain relief in both completed subjects was given by a very low pulse rate, which is a new finding for this therapy. Pain changed for up to several days when new stimulation parameters were set, suggesting that that frequent pain assessment is need to correctly titrate stimulation parameters. Visual side-effects were the only observed complication of stimulation, but they disappeared when a very low, maximally analgesic pulse rate was set. Thus this therapy is not only more effective at lower pulse rates, it is also safer. No serious adverse effects have been observed. Protocols (FDA and IRB) were modified to extend study of each subject for 2 additional years (funded by other sources), and to use a device (PC+S) that additionally allows recording from electrodes for added information. A no-cost extension year is in progress