In this prospective study the authors' objective was to evaluate the accuracy of deep brain stimulation (DBS) electrode placement using image guidance for direct anatomical targeting with ...intraoperative CT.
Preoperative 3-T MR images were merged with intraoperative CT images for planning. Electrode targets were anatomical, based on the MR images. A skull-mounted NexFrame system was used for electrode placement, and all procedures were performed under general anesthesia. After electrode placement, intraoperative CT images were merged with trajectory planning images to calculate accuracy. Accuracy was assessed by both vector error and deviation off the planned trajectory.
Sixty patients (33 with Parkinson disease, 26 with essential tremor, and 1 with dystonia) underwent the procedure. Patient's mean age was 64 ± 9.5 years. Over an 18-month period, 119 electrodes were placed (all bilateral, except one). Electrode implant locations were the ventral intermediate nucleus (VIM), globus pallidus internus (GPI), and subthalamic nucleus (STN) in 25, 23, and 12 patients, respectively. Target accuracy measurements were as follows: mean vector error 1.59 ± 1.11 mm and mean deviation off trajectory 1.24 ± 0.87 mm. There was no statistically significant difference between the accuracy of left and right brain electrodes. There was a statistically significant (negative) correlation between the distance of the closest approach of the electrode trajectory to the ventricular wall of the lateral ventricle and vector error (r(2) = -0.339, p < 0.05, n = 76), and the deviation from the planned trajectory (r(2) = -0.325, p < 0.05, n = 77). Furthermore, when the distance from the electrode trajectory and the ventricular wall was < 4 mm, the correlation of the ventricular distance to the deviation from the planned trajectory was stronger (r(2) = -0.419, p = 0.05, n = 19). Electrodes placed in the GPI were significantly more accurate than those placed in the VIM (p < 0.05). Only 1 of 119 electrodes required intraoperative replacement due to a vector error > 3 mm. In this series there was one infection and no intraparenchymal hemorrhages.
Placement of DBS electrodes using an intraoperative CT scanner and the NexFrame achieves an accuracy that is at least comparable to other methods.
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.
Pain surgery is one of the historic foundations of neurological surgery. The authors present a review of contemporary concepts in surgical pain management, with reference to past successes and ...failures, what has been learned as a subspecialty over the past 50 years, as well as a vision for current and future practice. This subspecialty confronts problems of cancer pain, nociceptive pain, and neuropathic pain. For noncancer pain, ablative procedures such as dorsal root entry zone lesions and rhizolysis for trigeminal neuralgia (TN) should continue to be practiced. Other procedures, such as medial thalamotomy, have not been proven effective and require continued study. Dorsal rhizotomy, dorsal root ganglionectomy, and neurotomy should probably be abandoned. For cancer pain, cordotomy is an important and underutilized method for pain control. Intrathecal opiate administration via an implantable system remains an important option for cancer pain management. While there are encouraging results in small case series, cingulotomy, hypophysectomy, and mesencephalotomy deserve further detailed analysis. Electrical neuromodulation is a rapidly changing discipline, and new methods such as high-frequency spinal cord stimulation (SCS), burst SCS, and dorsal root ganglion stimulation may or may not prove to be more effective than conventional SCS. Despite a history of failure, deep brain stimulation for pain may yet prove to be an effective therapy for specific pain conditions. Peripheral nerve stimulation for conditions such as occipital neuralgia and trigeminal neuropathic pain remains an option, although the quality of outcomes data is a challenge to these applications. Based on the evidence, motor cortex stimulation should be abandoned. TN is a mainstay of the surgical treatment of pain, particularly as new evidence and insights into TN emerge. Pain surgery will continue to build on this heritage, and restorative procedures will likely find a role in the armamentarium. The challenge for the future will be to acquire higher-level evidence to support the practice of surgical pain management.
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.
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.
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.
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.
Pain relief following microvascular decompression (MVD) for trigeminal neuralgia (TN) may be related to pain type, degree of neurovascular conflict, arterial compression, and location of compression. ...The objective of this study was to construct a predictive pain-free scoring system based on clinical and radiographic factors that can be used to preoperatively prognosticate long-term outcomes for TN patients following surgical intervention (MVD or internal neurolysis IN). It was hypothesized that contributing factors would include pain type, presence of an artery or vein, neurovascular conflict severity, and compression location (root entry zone).
At the authors' institution 275 patients with type 1 or type 2 TN (TN1 or TN2) underwent MVD or IN following preoperative high-resolution brain MRI studies. Outcome data were obtained retrospectively by chart review and/or phone follow-up. Characteristics of neurovascular conflict were obtained from preoperative MRI studies. Factors that resulted in a probability value of < 0.05 on univariate logistic regression analyses were entered into a multivariate Cox regression analysis in a backward stepwise fashion. For the multivariate analysis, significance at the 0.15 level was used. A prognostic system was then devised with 4 possible scores (0, 1, 2, or 3) and pain-free survival analyses conducted.
Univariate predictors of pain-free survival were pain type (p = 0.013), presence of any vessel (p = 0.042), and neurovascular compression severity (p = 0.038). Scores of 0, 1, 2, and 3 were found to be significantly different in regard to pain-free survival (log rank, p = 0.005). At 5 and 10 years there were 36%, 43%, 61%, and 69%, and 36%, 43%, 56%, and 67% pain-free survival rates in groups 0, 1, 2, and 3, respectively. While TN2 patients had worse outcomes regardless of score, a subgroup analysis of TN1 patients with higher neurovascular conflict (score of 3) had significantly better outcomes than TN1 patients without severe neurovascular conflict (score of 1) (log rank, p = 0.005). Regardless of pain type, those patients with severe neurovascular conflict were more likely to have arterial compression (99%) compared to those with low neurovascular conflict (p < 0.001).
Pain-free survival was predicted by a scoring system based on preoperative clinical and radiographic findings. Higher scores predicted significantly better pain relief than lower scores. TN1 patients with severe neurovascular conflict had the best long-term pain-free outcome.
When used to treat craniofacial pain, CT-guided trigeminal tractotomy-nucleotomy (TR-NC) is usually performed with local anesthesia. Unfortunately, local anesthesia is insufficient for patients with ...such severe pain that they cannot tolerate the required head positioning while awake. This study aimed to contextualize previous findings associated with TR-NC performed under general anesthesia. The authors examined clinical and operative factors that could impact postoperative pain outcomes.
This is a retrospective single-institution cohort study of patients who underwent a percutaneous CT-guided TR-NC under general anesthesia at a single institution between 2012 and 2019. Outcome data were analyzed.
Twenty-five patients underwent CT-guided TR-NC procedures under general anesthesia; 23 met the inclusion criteria and underwent a total of 31 procedures. The procedure success rate was 74% (23/31). Approximately 50% and 40% of procedures provided pain relief for at least 6 and 12 months, respectively. The median duration of pain relief was 153 days. Adverse events, all minor and transient, occurred following 6/31 (19%) of procedures. Patients with a body mass index > 25 were less likely to experience a successful TR-NC (p = 0.045). Higher electrode ablation temperatures (p = 0.033) and more medial entry trajectories relative to the midsagittal plane (p = 0.029) characterized successful procedures.
These results suggest that CT-guided TR-NC performed under general anesthesia is safe and effective. Postoperative outcomes were found to be associated with a number of clinical and operative factors. Such associations should be further explored and evaluated in the context of future, better-powered analyses.
Objective: To identify the role of bilateral internal iliac artery (IIA) ligation on reducing blood loss in abnormally invasive placenta (AIP) undergoing caesarean hysterectomy.
Methods: In this ...parallel-randomized control trial, 57 pregnant females with ultrasound features suggestive of AIP were enrolled. They were randomized into two groups; IIA group (n = 29 cases) performed bilateral IIA ligation followed by caesarean hysterectomies, while Control group (n = 28 cases) underwent caesarean hysterectomy only. The main outcome was the difference in the estimated intraoperative blood loss between the two groups.
Results: There was no significant difference between the two groups regarding the intraoperative estimated blood loss (1632 ± 804 versus 1698 ± 1251, p value .83). The operative procedure duration (minutes) (223 ± 66 versus 171 ± 41.4, p value .001) varied significantly between the two groups.
Conclusions: Bilateral internal iliac artery ligation, in cases of AIP undergoing caesarean hysterectomy, is not recommended for routine practice to minimize blood loss intraoperatively.
Declarative memory encoding, consolidation, and retrieval require the integration of elements encoded in widespread cortical locations. The mechanism whereby such "binding" of different components of ...mental events into unified representations occurs is unknown. The "binding-by-synchrony" theory proposes that distributed encoding areas are bound by synchronous oscillations enabling enhanced communication. However, evidence for such oscillations is sparse. Brief high-frequency oscillations ("ripples") occur in the hippocampus and cortex and help organize memory recall and consolidation. Here, using intracranial recordings in humans, we report that these ∼70-ms-duration, 90-Hz ripples often couple (within ±500 ms), co-occur (≥ 25-ms overlap), and, crucially, phase-lock (have consistent phase lags) between widely distributed focal cortical locations during both sleep and waking, even between hemispheres. Cortical ripple co-occurrence is facilitated through activation across multiple sites, and phase locking increases with more cortical sites corippling. Ripples in all cortical areas co-occur with hippocampal ripples but do not phase-lock with them, further suggesting that cortico-cortical synchrony is mediated by cortico-cortical connections. Ripple phase lags vary across sleep nights, consistent with participation in different networks. During waking, we show that hippocampo-cortical and cortico-cortical coripples increase preceding successful delayed memory recall, when binding between the cue and response is essential. Ripples increase and phase-modulate unit firing, and coripples increase high-frequency correlations between areas, suggesting synchronized unit spiking facilitating information exchange. co-occurrence, phase synchrony, and high-frequency correlation are maintained with little decrement over very long distances (25 cm). Hippocampo-cortico-cortical coripples appear to possess the essential properties necessary to support binding by synchrony during memory retrieval and perhaps generally in cognition.
Processing auditory human speech requires both detection (early and transient) and analysis (sustained). We analyzed high gamma (70–110 Hz) activity of intracranial electroencephalography waveforms ...acquired during an auditory task that paired forward speech, reverse speech, and signal correlated noise. We identified widespread superior temporal sites with sustained activity responding only to forward and reverse speech regardless of paired order. More localized superior temporal auditory onset sites responded to all stimulus types when presented first in a pair and responded in recurrent fashion to the second paired stimulus in select conditions even in the absence of interstimulus silence; a novel finding. Auditory onset activity to a second paired sound recurred according to relative salience, with evidence of partial suppression during linguistic processing. We propose that temporal lobe auditory onset sites facilitate a salience detector function with hysteresis of 200 ms and are influenced by cortico-cortical feedback loops involving linguistic processing and articulation.
We aimed to assess, in patients with perirolandic gliomas and gliomas originating from other regions, survival, functional outcomes, and seizure control and, in addition, to identify any clinical ...characteristics predictive of progression-free survival, overall survival, and seizure control.
We retrospectively analyzed 87 patients who underwent resection of World Health Organization grade II or III gliomas at a single institution between 2009 and 2021. Tumors were classified by topographic involvement. One-year postoperative functional status was quantified with Karnofsky Performance Status. One-year seizure control was defined by Engel seizure classification. Dichotomous and categorical variables were reported as counts and percentages and compared using Fisher exact test. A Cox regression model was used to identify covariates that affect progression-free survival and overall survival.
Patients with perirolandic gliomas had similar survival and functional outcomes to patients with gliomas from other regions and a low rate of lasting neurologic deficits. Patients with perirolandic gliomas had comparatively worse long-term seizure outcomes (approached statistical significance). Perirolandic involvement (hazard ratio HR, 0.10; 95% confidence interval CI, 0.02–0.46; P = 0.005) and preoperative seizures (HR, 0.14; 95% CI, 0.02–0.62; P = 0.017) conferred a lower likelihood of durable seizure control, whereas increased extent of resection (HR, 1.07; 95% CI, 1.03–1.12; P = 0.003) enhanced the likelihood of seizure freedom.
Despite proximity to or presence in eloquent structures, perirolandic gliomas can largely be resected without incurring worse functional outcomes. Patients with perirolandic gliomas should be considered for maximal safe resection to optimize survival outcomes and improve seizure control.
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