Louis A. Whitworth

Sacral neuromodulation for chronic pain conditions.

Some of the pelvic pain syndromes seem to have features of neurogenic inflammation and neuropathic pain in common. As opposed to being separate disease entities, they may represent a spectrum of clinical presentations of CRPS I of the pelvis. Sacral nerve root stimulation provides good symptomatic relief of pain and voiding dysfunction. The techniques of retrograde root stimulation may offer superior results with fewer complications and lead migrations when compared with other methods. Perhaps neuromodulation should be used earlier in the treatment paradigm for these disorders, before the potentially injurious procedures of hydrodistention, bladder installations, and cystectomies.

Application of spinal ablative techniques for the treatment of benign chronic painful conditions: history, methods, and outcomes.

Study Design. The literature on current neuroablative techniques for treating benign chronic painful conditions is comprehensively reviewed. Objective. To provide the reader with an understanding of the indications, techniques, and outcomes for the various ablative procedures used to treat chronic pain syndromes. Summary of Background Data. Neuromodulatory techniques are rapidly supplanting the traditional neuroablative procedures used to treat many types of pain. Methods. A MEDLINE search was conducted for each of the following procedures: radiofrequency facet denervation, cordotomy, myelotomy, sympathectomy, DREZotomy, rhizotomy, and ganglionectomy. In the review of each article, special attention given to the outcome, length of follow-up, complications, and number of patients. Summaries of this data were compiled to provided historical perspective, current techniques, indications, and outcomes for each of the aforementioned procedures. The outcomes cited for each procedure generally represent the data from the three or four largest series with adequate follow-up length. Results. The aforementioned procedures have 30% to 90% success rates, with success defined as at least a 50% reduction in perceived pain. These results tend to diminish with time. However, most are associated with a significant degree of morbidity and relatively high complication rates. In addition, many of the techniques lead to deafferentation pain syndromes. Conclusions. Ablative spinal techniques offer pain relief for many patients, but the use of these methods should be considered carefully in the light of available nondestructive procedures that may achieve similar goals with potentially lower morbidities.

Subcallosal cingulate deep brain stimulation for treatment-resistant depression: a multisite, randomised, sham-controlled trial

BACKGROUND Deep brain stimulation (DBS) of the subcallosal cingulate white matter has shown promise as an intervention for patients with chronic, unremitting depression. To test the safety and efficacy of DBS for treatment-resistant depression, a prospective, randomised, sham-controlled trial was conducted. METHODS Participants with treatment-resistant depression were implanted with a DBS system targeting bilateral subcallosal cingulate white matter and randomised to 6 months of active or sham DBS, followed by 6 months of open-label subcallosal cingulate DBS. Randomisation was computer generated with a block size of three at each site before the site started the study. The primary outcome was frequency of response (defined as a 40% or greater reduction in depression severity from baseline) averaged over months 4-6 of the double-blind phase. A futility analysis was performed when approximately half of the proposed sample received DBS implantation and completed the double-blind phase. At the conclusion of the 12-month study, a subset of patients were followed up for up to 24 months. The study is registered at ClinicalTrials.gov, number NCT00617162. FINDINGS Before the futility analysis, 90 participants were randomly assigned to active (n=60) or sham (n=30) stimulation between April 10, 2008, and Nov 21, 2012. Both groups showed improvement, but there was no statistically significant difference in response during the double-blind, sham-controlled phase (12 [20%] patients in the stimulation group vs five [17%] patients in the control group). 28 patients experienced 40 serious adverse events; eight of these (in seven patients) were deemed to be related to the study device or surgery. INTERPRETATION This study confirmed the safety and feasibility of subcallosal cingulate DBS as a treatment for treatment-resistant depression but did not show statistically significant antidepressant efficacy in a 6-month double-blind, sham-controlled trial. Future studies are needed to investigate factors such as clinical features or electrode placement that might improve efficacy. FUNDING Abbott (previously St Jude Medical).

C1‐C2 Sublaminar Insertion of Paddle Leads for the Management of Chronic Painful Conditions of the Upper Extremity

While spinal cord stimulation has commonly been carried out using percutaneous leads, these devices have limitations in cervical implants due to problems with positional stimulation and lead migration. Paddle leads, by virtue of their design, are more stable in their apposition to the neural elements; however, mid and lower cervical insertions have been associated with both acute and subacute spinal cord injuries. These complications are likely related to limitations in canal diameter, as paddle leads occupy a greater volume than percutaneous leads. At C1‐C2, the space around the spinal cord is more generous, and thus allows greater room for insertion of leads. We report a series of patients treated with a technique for the implantation of a C1‐C2 paddle electrode that capitalizes on this anatomy while still meeting the need for paresthetic overlap in patients with upper extremity pain syndromes. While the technique is not novel, it has not yet been popularized ( 1 ). This paper is presented to increase implanters’ awareness of the method, its safety and utility. Twenty consecutive patients with neuropathic pain syndromes of the upper extremity were implanted using this technique. Surgical implantation of leads was done under a general anesthetic. An upper cervical incision was used, and after performing minimal laminotomies at C1 and C2, the lead was passed rostro‐caudally under direct visualization beneath the lamina. Paresthetic overlap of pain segments was achieved in all but one patient. Pre and postoperative VAS scores were compared to evaluate effectiveness of treatment. Eighteen of 20 patients reported a significant benefit from stimulation, with an average of 63 percent reduction in pain scores. The only complication was a malpositioned lead that required reoperation to adjust placement. No patient suffered neurologic sequelae as a result of this procedure. We have found C1‐C2 sublaminar insertions of paddle leads to be a safe and effective way of treating neuropathic pain phenomenon involving the upper extremity. To further assess the relative benefit over percutaneous leads, a prospective trial would be required.

Effect of gravity and microgravity on intracranial pressure

Astronauts have recently been discovered to have impaired vision, with a presentation that resembles syndromes of elevated intracranial pressure on Earth. Gravity has a profound effect on fluid distribution and pressure within the human circulation. In contrast to prevailing theory, we observed that microgravity reduces central venous and intracranial pressure. This being said, intracranial pressure is not reduced to the levels observed in the 90 deg seated upright posture on Earth. Thus, over 24 h in zero gravity, pressure in the brain is slightly above that observed on Earth, which may explain remodelling of the eye in astronauts.

Multi-staged robotic stereotactic radiosurgery for large cerebral arteriovenous malformations

PURPOSE To investigate a multi-staged robotic stereotactic radiosurgery (SRS) delivery technique for the treatment of large cerebral arteriovenous malformations (AVMs). The treatment planning process and strategies to optimize both individual and composite dosimetry are discussed. METHODS Eleven patients with large (30.7 ± 19.2 cm(3)) AVMs were selected for this study. A fiducial system was designed for fusion of targets between planar angiograms and simulation CT scans. AVMs were contoured based on single contrast CT, MRI and orthogonal angiogram images. AVMs were divided into 3-8 sub-target volumes (3-7 cm(3)) for sequential treatment at 1-4 week intervals to a prescription dose of 16-20 Gy. Forward and inversely developed treatment plans were optimized for 95% coverage of the total AVM volume by dose summation from each sub-volume, while minimizing dose to surrounding tissues. Dose-volume analysis was used to evaluate the PTV coverage, dose conformality (CI), and R50 and V12 Gy parameters. RESULTS The treatment workflow was commissioned and able to localize within 1mm. Inverse optimization outperformed forward planning for most patients for each index considered. Dose conformality was shown comparable to staged Gamma Knife treatments. CONCLUSION The CyberKnife system is shown to be a practical delivery platform for multi-staged treatments of large AVMs using forward or inverse planning techniques.

Spina Bifida Occulta as a Relative Contraindication for Percutaneous Retrograde Lead Insertion for Sacral Nerve Root Stimulation

Percutaneous retrograde lead insertion for sacral nerve root stimulation is a newly described technique being applied to a variety of pain disorders. The success of the procedure rests in a defined epidural space such that there is unimpeded progression of the lead into the desired location. It is hypothesized that any condition that results in anatomic compromise of the epidural space would prevent the success of the procedure.

Developing a Deep Brain Stimulation Neuromodulation Network for Parkinson Disease, Essential Tremor, and Dystonia: Report of a Quality Improvement Project.

Objective To develop a process to improve patient outcomes from deep brain stimulation (DBS) surgery for Parkinson disease (PD), essential tremor (ET), and dystonia. Methods We employed standard quality improvement methodology using the Plan-Do-Study-Act process to improve patient selection, surgical DBS lead implantation, postoperative programming, and ongoing assessment of patient outcomes. Results The result of this quality improvement process was the development of a neuromodulation network. The key aspect of this program is rigorous patient assessment of both motor and non-motor outcomes tracked longitudinally using a REDCap database. We describe how this information is used to identify problems and to initiate Plan-Do-Study-Act cycles to address them. Preliminary outcomes data is presented for the cohort of PD and ET patients who have received surgery since the creation of the neuromodulation network. Conclusions Careful outcomes tracking is essential to ensure quality in a complex therapeutic endeavor like DBS surgery for movement disorders. The REDCap database system is well suited to store outcomes data for the purpose of ongoing quality assurance monitoring.

359 Delayed Treatment of Ruptured Arteriovenous Malformations: Is It Ok to Wait?

INTRODUCTION Emergent surgery on a ruptured brain arteriovenous malformation (AVM) is indicated for a large hematoma in an acutely deteriorating patient. The majority of ruptured AVMs, however, present in clinically stable patients with neurological deficits. Controversy exists with respect to the timing of treatment for ruptured AVMs in these stable patients. This study aims to determine the safety of delaying AVM treatment in clinically stable patients by investigating the rate of rehemorrhage in a cohort of patients with ruptured brain AVMs. METHODS Patients presenting to our institution from January 2000 to December 2015 with ruptured brain AVMs treated at least 4 weeks posthemorrhage were included in the analysis. Exclusion criteria were ruptured AVMs that required emergent surgery involving AVM resection, previous treatment at another institution, or subacute AVM treatment. The primary outcome measure was time from initial hemorrhage to rehemorrhage. Patient follow-up data were included up until the point of AVM treatment. RESULTS Of the 103 ruptured AVMs (49 M:54 F) meeting inclusion criteria, the median time from rupture to treatment or rehemorrhage was 112 days (interquartile range [IQR]: 110). Six (5.8%) patients rehemorrhaged in a median of 248 days (IQR: 1331). Two of these patients rehemorrhaged on the same day of their index hemorrhage. The total at-risk period was 19 445 patient-days, yielding a rehemorrhage risk of 11.3% per patient-year, or 0.93% per patient-month. CONCLUSION Our data support stabilizing a patient after the initial AVM rupture. It is safe to closely monitor the patient, initiate the rehabilitation process, and then, in a semielective manner, bring the patient back for treatment. Delaying intervention for 4 weeks after initial hemorrhage subjects the patient to a low (<1%) risk of rehemorrhage.

Cystic Lesions as a Rare Complication of Deep Brain Stimulation

DBS is a typically well‐tolerated operation for treatment of Parkinsons disease, dystonia, and essential tremor (ET). Complications related to the surgical procedure and implanted hardware may occur. More commonly reported complications include hemorrhage, seizure, confusion, and infection. In this article, we report on a rare, but important, complication of DBS surgery, a brain cyst formation at the tip of the implanted ventralis intermedius nucleus (VIM) DBS lead in 2 patients who underwent the procedure at 2 different centers. The indication for surgery was debilitating ET, and in both cases, there was development of a delayed‐onset neurological deficit associated with an internal capsule/thalamic cystic lesion formation located at the tip of the DBS lead. Case 1 presented within a few months post‐DBS, whereas case 2 had a 10‐mo delay to onset of symptoms. No clinical and radiological signs of infection were observed and both DBS systems were explanted with uneventful recovery.