Asleep Deep Brain Stimulation Reduces Incidence of Intracranial Air during Electrode Implantation

BACKGROUND

Asleep deep brain stimulation (aDBS) implantation replaces microelectrode recording for image-guided implantation, shortening the operative time and reducing cerebrospinal fluid egress. This may decrease pneumocephalus, thus decreasing brain shift during implantation.

OBJECTIVE

To compare the incidence and volume of pneumocephalus during awake (wkDBS) and aDBS procedures.

METHODS

A retrospective review of bilateral DBS cases performed at Oregon Health & Science University from 2009 to 2017 was undertaken. Postimplantation imaging was reviewed to determine the presence and volume of intracranial air and measure cortical brain shift.

RESULTS

Among 371 patients, pneumocephalus was noted in 66% of wkDBS and 15.6% of aDBS. The average volume of air was significantly higher in wkDBS than aDBS (8.0 vs. 1.8 mL). Volumes of air greater than 7 mL, which have previously been linked to brain shift, occurred significantly more frequently in wkDBS than aDBS (34 vs 5.6%). wkDBS resulted in significantly larger cortical brain shifts (5.8 vs. 1.2 mm).

CONCLUSIONS

We show that aDBS reduces the incidence of intracranial air, larger air volumes, and cortical brain shift. Large volumes of intracranial air have been correlated to shifting of brain structures during DBS procedures, a variable that could impact accuracy of electrode placement.

Image-Guided, Asleep Deep Brain Stimulation

Deep brain stimulation (DBS) has become an established treatment for medically refractory movement disorders including Parkinson's disease, essential tremor, and dystonia. The field of DBS continues to evolve with advances in patient selection, target identification, electrode and pulse generator technology, and the development of more effective stimulation paradigms such as closed-loop stimulation. Furthermore, as the safety and efficacy of DBS improves through better hardware design and deeper understanding of its mechanisms of action, the indications for DBS will continue to expand to cover a wider range of disorders. Finally, the recent approval of MR-guided focused ultrasound for the treatment of essential tremor and potentially other movement disorders heralds a resurgence in lesion creation as a viable alternative to DBS for selected patients.

Clinical outcomes of asleep vs awake deep brain stimulation for Parkinson disease

Objective:

To compare motor and nonmotor outcomes at 6 months of asleep deep brain stimulation (DBS) for Parkinson disease (PD) using intraoperative imaging guidance to confirm electrode placement vs awake DBS using microelectrode recording to confirm electrode placement.

Methods:

DBS candidates with PD referred to Oregon Health & Science University underwent asleep DBS with imaging guidance. Six-month outcomes were compared to those of patients who previously underwent awake DBS by the same surgeon and center. Assessments included an “off”-levodopa Unified Parkinson’s Disease Rating Scale (UPDRS) II and III, the 39-item Parkinson's Disease Questionnaire, motor diaries, and speech fluency.

Results:

Thirty participants underwent asleep DBS and 39 underwent awake DBS. No difference was observed in improvement of UPDRS III (+14.8 ± 8.9 vs +17.6 ± 12.3 points, p = 0.19) or UPDRS II (+9.3 ± 2.7 vs +7.4 ± 5.8 points, p = 0.16). Improvement in “on” time without dyskinesia was superior in asleep DBS (+6.4 ± 3.0 h/d vs +1.7 ± 1.2 h/d, p = 0.002). Quality of life scores improved in both groups (+18.8 ± 9.4 in awake, +8.9 ± 11.5 in asleep). Improvement in summary index (p = 0.004) and subscores for cognition (p = 0.011) and communication (p < 0.001) were superior in asleep DBS. Speech outcomes were superior in asleep DBS, both in category (+2.77 ± 4.3 points vs −6.31 ± 9.7 points (p = 0.0012) and phonemic fluency (+1.0 ± 8.2 points vs −5.5 ± 9.6 points, p = 0.038).

Conclusions:

Asleep DBS for PD improved motor outcomes over 6 months on par with or better than awake DBS, was superior with regard to speech fluency and quality of life, and should be an option considered for all patients who are candidates for this treatment.

Clinicaltrials.gov identifier:

NCT01703598.

Classification of evidence:

This study provides Class III evidence that for patients with PD undergoing DBS, asleep intraoperative CT imaging–guided implantation is not significantly different from awake microelectrode recording–guided implantation in improving motor outcomes at 6 months.

Deep Brain Stimulation Targets, Technology, and Trials: Two Decades of Progress

ABBREVIATIONS

AD, Alzheimer diseaseDBS, Deep brain stimulationFDA, Food and Drug AdministrationMER, Microelectrode recording.

Cost analysis of awake versus asleep deep brain stimulation: a single academic health center experience

OBJECT

The objective of this study was to compare the cost of deep brain stimulation (DBS) performed awake versus asleep at a single US academic health center and to compare costs across the University HealthSystem Consortium (UHC) Clinical Database.

METHODS

Inpatient and outpatient demographic and hospital financial data for patients receiving a neurostimulator lead implant (from the first quarter of 2009 to the second quarter of 2014) were collected and analyzed. Inpatient charges included those associated with International Classification of Diseases, Ninth Revision (ICD-9) procedure code 0293 (implantation or replacement of intracranial neurostimulator lead). Outpatient charges included all preoperative charges ≤ 30 days prior to implant and all postoperative charges ≤ 30 days after implant. The cost of care based on reported charges and a cost-to-charge ratio was estimated. The UHC database was queried (January 2011 to March 2014) with the same ICD-9 code. Procedure cost data across like hospitals (27 UHC hospitals) conducting similar DBS procedures were compared.

RESULTS

Two hundred eleven DBS procedures (53 awake and 158 asleep) were performed at a single US academic health center during the study period. The average patient age ( ± SD) was 65 ± 9 years old and 39% of patients were female. The most common primary diagnosis was Parkinson’s disease (61.1%) followed by essential and other forms of tremor (36%). Overall average DBS procedure cost was $39,152 ± $5340. Asleep DBS cost $38,850 ± $4830, which was not significantly different than the awake DBS cost of $40,052 ± $6604. The standard deviation for asleep DBS was significantly lower (p ≤ 0.05). In 2013, the median cost for a neurostimulator implant lead was $34,052 at UHC-affiliated hospitals that performed at least 5 procedures a year. At Oregon Health & Science University, the median cost was $17,150 and the observed single academic health center cost for a neurostimulator lead implant was less than the expected cost (ratio 0.97).

CONCLUSIONS

In this single academic medical center cost analysis, DBS performed asleep was associated with a lower cost variation relative to the awake procedure. Furthermore, costs compared favorably to UHC-affiliated hospitals. While asleep DBS is not yet standard practice, this center exclusively performs asleep DBS at a lower cost than comparable institutions.

Atypical facial pain in multiple sclerosis caused by spinal cord seizures: a case report and review of the literature

Background

Pain is a very commonly reported symptom and often drives patients to seek medical attention; however, it can prove a very difficult diagnostic conundrum and even more challenging to treat effectively. Accurately determining the primary pain generator is key, as certain conditions have efficacious medical and surgical treatments. We present a rare case of a man with multiple sclerosis presenting with spinal cord seizures causing dermatomal pain. While pain has been reported in the context of motor symptoms attributed to spinal cord seizures in a small number of spinal cord conditions, this case represents the first report of pain exclusively associated with spinal cord demyelination in multiple sclerosis.

Case presentation

We present the case of a 60-year-old Caucasian male patient with multiple sclerosis who reported a 5-year history of progressive pain in his left retroauricular region and superior left shoulder. He described this pain as sharp, episodic, and unrelenting and he was referred for consideration for surgical treatment of trigeminal neuralgia. He had no evidence of trigeminal nerve root pathology on magnetic resonance imaging, but did show dorsolateral spinal cord demyelination at the C3–4 level. His symptoms therefore represent an unusual presentation of spinal cord seizures.

Conclusions

Spinal cord seizures are rarely reported in multiple sclerosis and typically present with focal motor seizures. These have been reported to present with cramping dysesthesia and pruritus, though rarely with primary pain. Knowledge of uncommon pain presentations is critical for the increasing number of primary care physicians caring for patients with such chronic neurological diseases as it will guide management and referral patterns. This knowledge is also important for the treating neurologists and neurosurgeons. Neurosurgical intervention for trigeminal neuralgia poses considerable surgical risk, and it should be avoided where possible. Identifying the primary pain generator is, therefore, critical for accurate diagnosis and management.

Effect of Subthalamic Nucleus Stimulation on Pedunculopontine Nucleus Neural Activity

BACKGROUND

The pedunculopontine nucleus has recently been proposed as an alternative target for deep brain stimulation for the treatment of medically intractable Parkinson's disease. The suggested indication for pedunculopontine nucleus deep brain stimulation is severe and medically intractable axial symptoms such as gait and postural impairment.

OBJECTIVE

Our goal in this study was to describe the effects of subthalamic nucleus stimulation on pedunculopontine nucleus electrophysiological activity.

METHODS

Fourteen male Wistar rats were divided into a sham stimulation group and an experimental group. In both groups, electrodes were implanted bilaterally into the subthalamic nucleus and into the right pedunculopontine nucleus. Microelectrode recordings were carried out in both groups prior to and during subthalamic nucleus stimulation.

RESULTS

Subthalamic nucleus stimulation produced no clear inhibition of neuronal firing in the pedunculopontine nucleus. However, we found that stimulation of the subthalamic nucleus at 60 Hz produces some entrainment of pedunculopontine nucleus neuronal firing and a shift of subthalamic nucleus firing patterns to more tonic and random patterns. These results are consistent with the effects of deep brain stimulation on neuronal activity in the subthalamic nucleus and globus pallidus internus.

CONCLUSION

The result of this study provides additional evidence to improve our understanding of the mechanism of subthalamic nucleus-deep brain stimulation, and its physiological consequences.

Correlation of preoperative MRI with the long-term outcomes of dorsal root entry zone lesioning for brachial plexus avulsion pain

OBJECT Lesioning of the dorsal root entry zone (DREZotomy) is an effective treatment for brachial plexus avulsion (BPA) pain. The role of preoperative assessment with MRI has been shown to be unreliable for determining affected levels; however, it may have a role in predicting pain outcomes. Here, DREZotomy outcomes are reviewed and preoperative MRI is examined as a possible prognostic factor. METHODS A retrospective review was performed of an institutional database of patients who had undergone brachial plexus DREZ procedures since 1995. Preoperative MRI was examined to assess damage to the DREZ or dorsal horn, as evidenced by avulsion of the DREZ or T2 hyperintensity within the spinal cord. Phone interviews were conducted to assess the long-term pain outcomes. RESULTS Between 1995 and 2012, 27 patients were found to have undergone cervical DREZ procedures for BPA. Of these, 15 had preoperative MR images of the cervical spine available for review. The outcomes were graded from 1 to 4 as poor (no significant relief), good (more than 50% pain relief), excellent (more than 75% pain relief), or pain free, respectively. Overall, DREZotomy was found to be a safe, efficacious, and durable procedure for relief of pain due to BPA. The initial success rate was 73%, which declined to 66% at a median follow-up time of 62.5 months. Damage to the DREZ or dorsal horn was significantly correlated with poorer outcomes (p = 0.02). The average outcomes in patients without MRI evidence of DREZ or dorsal horn damage was significantly higher than in patients with such damage (3.67 vs 1.75, t-test; p = 0.001). A longer duration of pain prior to operation was also a significant predictor of treatment success (p = 0.004). CONCLUSIONS Overall, the DREZotomy procedure has a 66% chance of achieving meaningful pain relief on long-term follow-up. Successful pain relief is associated with the lack of damage to the DREZ and dorsal horn on preoperative MRI.

Compensatory stepping in Parkinson's disease is still a problem after deep brain stimulation randomized to STN or GPi

The effects of deep brain stimulation (DBS) on balance in people with Parkinson's disease (PD) are not well established. This study examined whether DBS randomized to the subthalamic nucleus (STN; n = 11) or globus pallidus interna (GPi; n = 10) improved compensatory stepping to recover balance after a perturbation. The standing surface translated backward, forcing subjects to take compensatory steps forward. Kinematic and kinetic responses were recorded. PD-DBS subjects were tested off and on their levodopa medication before bilateral DBS surgery and retested 6 mo later off and on DBS, combined with off and on levodopa medication. Responses were compared with PD-control subjects (n = 8) tested over the same timescale and 17 healthy control subjects. Neither DBS nor levodopa improved the stepping response. Compensatory stepping in the best-treated state after surgery (DBS+DOPA) was similar to the best-treated state before surgery (DOPA) for the PD-GPi group and the PD-control group. For the PD-STN group, there were more lateral weight shifts, a delayed foot-off, and a greater number of steps required to recover balance in DBS+DOPA after surgery compared with DOPA before surgery. Within the STN group five subjects who did not fall during the experiment before surgery fell at least once after surgery, whereas the number of falls in the GPi and PD-control groups were unchanged. DBS did not improve the compensatory step response needed to recover from balance perturbations in the GPi group and caused delays in the preparation phase of the step in the STN group.

Trigeminal neuralgia without neurovascular compression presents earlier than trigeminal neuralgia with neurovascular compression

OBJECT

Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). To characterize what may be distinct patient populations, the authors examined age at onset in patients with TN with and without NVC.

METHODS

A retrospective review of patients undergoing posterior fossa surgery for Type I TN at Oregon Health & Science University from 2009 to 2013 was undertaken. Charts were reviewed, and imaging and operative data were collected for patients with and without NVC. Mean, median, and the empirical cumulative distribution of onset age were determined. Statistical analysis was performed using Student t-test, Wilcoxon and Kolmogorov-Smirnoff tests, and Kaplan-Meier analysis. Multivariate analysis was performed using a Cox proportional hazards model.

RESULTS

The charts of 219 patients with TN were reviewed. There were 156 patients who underwent posterior fossa exploration and microvascular decompression or internal neurolysis: 129 patients with NVC and 27 without NVC. Mean age at symptoms onset for patients with and without NVC was 51.1 and 42.6 years, respectively. This difference (8.4 years) was significant (t-test: p = 0.007), with sufficient power to detect an effect size of 8.2 years. Median age between groups with and without NVC was 53.25 and 41.2 years, respectively (p = 0.003). Histogram analysis revealed a bimodal age at onset in patients without NVC, and cumulative distribution of age at onset revealed an earlier presentation of symptoms (p = 0.003) in patients without NVC. Chi-square analysis revealed a trend toward female predominance in patients without NVC, which was not significant (p = 0.08). Multivariate analysis revealed that age at onset was related to NVC but not sex, symptom side or distribution, or patient response to medical treatment.

CONCLUSIONS

NVC is neither sufficient nor necessary for the development of TN. Patients with TN without NVC may represent a distinct population of younger, predominantly female patients. Further research into the pathophysiology underlying this debilitating disease is needed.

Long-term efficacy and safety of internal neurolysis for trigeminal neuralgia without neurovascular compression

OBJECT Trigeminal neuralgia (TN) occurs and recurs in the absence of neurovascular compression (NVC). While microvascular decompression (MVD) is the most effective treatment for TN, it is not possible when NVC is not present. Therefore, the authors sought to evaluate the safety, efficacy, and durability of internal neurolysis (IN), or "nerve combing," as a treatment for TN without NVC. METHODS This was a retrospective review of all cases of Type 1 TN involving all patients 18 years of age or older who underwent evaluation (and surgery when appropriate) at Oregon Health & Science University between July 2006 and February 2013. Chart reviews and telephone interviews were conducted to assess patient outcomes. Pain intensity was evaluated with the Barrow Neurological Institute (BNI) Pain Intensity scale, and the Brief Pain Inventory-Facial (BPI-Facial) was used to assess general and face-specific activity. Pain-free survival and durability of successful pain relief (BNI pain scores of 1 or 2) were statistically evaluated with Kaplan-Meier analysis. Prognostic factors were identified and analyzed using Cox proportional hazards regression. RESULTS A total of 177 patients with Type 1 TN were identified. A subgroup of 27 was found to have no NVC on high-resolution MRI/MR angiography or at surgery. These patients were significantly younger than patients with classic Type 1 TN. Long-term follow-up was available for 26 of 27 patients, and 23 responded to the telephone survey. The median follow-up duration was 43.4 months. Immediate postoperative results were comparable to MVD, with 85% of patients pain free and 96% of patients with successful pain relief. At 1 year and 5 years, the rate of pain-free survival was 58% and 47%, respectively. Successful pain relief at those intervals was maintained in 77% and 72% of patients. Almost all patients experienced some degree of numbness or hypesthesia (96%), but in patients with successful pain relief, this numbness did not significantly impact their quality of life. There was 1 patient with a CSF leak and 1 patient with anesthesia dolorosa. Previous treatment for TN was identified as a poor prognostic factor for successful outcome. CONCLUSIONS This is the first report of IN with meaningful outcomes data. This study demonstrated that IN is a safe, effective, and durable treatment for TN in the absence of NVC. Pain-free outcomes with IN appeared to be more durable than radiofrequency gangliolysis, and IN appears to be more effective than stereotactic radiosurgery, 2 alternatives to posterior fossa exploration in cases of TN without NVC. Given the younger age distribution of patients in this group, consideration should be given to performing IN as an initial treatment. Accrual of further outcomes data is warranted.

An ACGME Duty Hour Compliant 3-Person Night Float System for Neurological Surgery Residency Programs

BACKGROUND

In 2003, the Accreditation Council for Graduate Medical Education (ACGME) instituted the 24+6-hour work schedule and 80-hour workweek, and in 2011, it enhanced work hour and supervision standards.

INNOVATION

In response, Oregon Health & Science University's (OHSU) neurological surgery residency instituted a 3-person night float system.

METHODS

We analyzed work hour records and operative experience for 1 year before and after night float implementation in a model that shortened a combined introductory research and basic clinical neurosciences rotation from 12 to 6 months. We analyzed residents' perception of the system using a confidential survey. The ACGME 2011 work hour standards were applied to both time periods.

RESULTS

AFTER NIGHT FLOAT IMPLEMENTATION, THE NUMBER OF DUTY HOUR VIOLATIONS WAS REDUCED: 28-hour shift (11 versus 235), 8 hours off between shifts (2 versus 20), 80 hours per week (0 versus 17), and total violations (23 versus 275). Violations increased only for the less than 4 days off per 4-week interval rule (10 versus 3). No meaningful difference was seen in the number of operative cases performed per year at any postgraduate year (PGY) training level: PGY-2 (336 versus 351), PGY-3 (394 versus 354), PGY-4 (803 versus 802), PGY-5 (1075 versus 1040), PGY-7 (947 versus 913), and total (3555 versus 3460). Residents rated the new system favorably.

CONCLUSIONS

To meet 2011 ACGME duty hour standards, the OHSU neurological surgery residency instituted a 3-person night float system. A nearly complete elimination of work hour violations did not affect overall resident operative experience.

Trigeminal neuralgia occurs and recurs in the absence of neurovascular compression

Object

Vascular compression of the trigeminal nerve is the most common factor associated with the etiology of trigeminal neuralgia (TN). Microvascular decompression (MVD) has proven to be the most successful and durable surgical approach for this disorder. However, not all patients with TN manifest unequivocal neurovascular compression (NVC). Furthermore, over time patients with an initially successful MVD manifest a relentless rate of TN recurrence.

Methods

The authors performed a retrospective review of cases of TN Type 1 (TN1) or Type 2 (TN2) involving patients 18 years or older who underwent evaluation (and surgery when indicated) at Oregon Health & Science University between July 2006 and February 2013. Surgical and imaging findings were correlated.

Results

The review identified a total of 257 patients with TN (219 with TN1 and 38 with TN2) who underwent high-resolution MRI and MR angiography with 3D reconstruction of combined images using OsiriX. Imaging data revealed that the occurrence of TN1 and TN2 without NVC was 28.8% and 18.4%, respectively. A subgroup of 184 patients underwent surgical exploration. Imaging findings were highly correlated with surgical findings, with a sensitivity of 96% for TN1 and TN2 and a specificity of 90% for TN1 and 66% for TN2.

Conclusions

Magnetic resonance imaging detects NVC with a high degree of sensitivity. However, despite a diagnosis of TN1 or TN2, a significant number of patients have no NVC. Trigeminal neuralgia clearly occurs and recurs in the absence of NVC.

The effect of deep brain stimulation randomized by site on balance in Parkinson's disease

BACKGROUND

The effect of the surgical site of DBS on balance and gait in Parkinson's Disease (PD) is uncertain. This is the first double-blind study of subjects randomized to either the STN (N = 14) or GPi (N = 14) who were assessed on a range of clinical balance measures.

METHODS

Balance testing occurred before and 6 months postsurgery. A control PD group was tested over the same period without surgery (N = 9). All subjects were tested on and off medication and DBS subjects were also tested on and off DBS. The Postural Instability and Gait Disability items of the UPDRS and additional functional tests, which we call the Balance and Gait scale, were assessed. Activities of Balance Confidence and Activities of Daily Living questionnaires were also recorded.

RESULTS

Balance was not different between the best-treated states before and after DBS surgery for both sites. Switching DBS on improved balance scores, and scores further improved with medication, compared to the off state. The GPi group showed improved performance in the postsurgery off state and better ratings of balance confidence after surgery, compared to the STN group.

CONCLUSIONS

Clinical measures of balance function for both the STN and GPi sites showed that balance did not improve beyond the best medically treated state before surgery. Both clinical balance testing in the off/off state and self-reported balance confidence after surgery showed better performance in the GPi than the STN group.