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Posterior Reversible Encephalopathy Syndrome as a Complication of Induced Hypertension in Subarachnoid Hemorrhage: A Case-Control Study

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 223–230

Induced hypertension (IH) remains the mainstay of medicalmanagement for delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH). However, raising blood pressure above normal levels may be associated with systemic and neurological complications, of which posterior reversible encephalopathy syndrome (PRES) has been increasingly recognized.

OBJECTIVE: To ascertain the frequency and predisposing factors for PRES during IH therapy.

METHODS: We identified 68 patients treated with IH from 345 SAH patients over a 3- yr period. PRES was diagnosed based on clinical suspicion, confirmed by imaging. We extracted additional data on IH, including baseline and highest target mean arterial pressure (MAP), comparing PRES to IH-treated controls.

RESULTS: Five patients were diagnosed with PRES at median 6.6 d (range 1-8 d) from vasopressor initiation. All presented with lethargy, 3 had new focal deficits, and 1 had a seizure. Although baseline MAP (prior to DCI) did not differ between cases and controls, bothMAP immediately prior to IH (112 vs 90) and highestMAP targetedwere greater (140 vs 120mmHg, both P<.01).Magnitude ofMAP elevation was greater (54 vs 34 above baseline, P = .004) while degree of IH was not (37 vs 38 above pre-IH MAP). All 4 surviving PRES patients had complete resolution with IH discontinuation.

CONCLUSION: PRES was diagnosed in 7% of SAH patients undergoing IH therapy, most oftenwhenMAP was raisedwell above baseline to levels that exceed traditional autoregulatory thresholds. High suspicion for this reversible disorder appears warranted in the face of unexplained neurological deterioration during aggressive IH.

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Machine learning—aided personalized DTI tractographic planning for deep brain stimulation of the superolateral medial forebrain bundle using HAMLET

Acta Neurochirurgica (2019) 161:1559–1569

Growing interest exists for superolateral medial forebrain bundle (slMFB) deep brain stimulation (DBS) in psychiatric disorders. The surgical approach warrants tractographic rendition. Commercial stereotactic planning systems use deterministic tractography which suffers from inherent limitations, is dependent on manual interaction (ROI definition), and has to be regarded as subjective. We aimed to develop an objective but patient-specific tracking of the slMFB which at the same time allows the use of a commercial surgical planning system in the context of deep brain stimulation.

Methods The HAMLET (Hierarchical Harmonic Filters for Learning Tracts from Diffusion MRI) machine learning approach was introduced into the standardized workflow of slMFB DBS tractographic planning on the basis of patientspecific dMRI. Rendition of the slMFB with HAMLET serves as an objective comparison for the refinement of the deterministic tracking procedure. Our application focuses on the tractographic planning of DBS (N = 8) for major depression and OCD.

Results Previous results have shown that only fibers belonging to the ventral tegmental area to prefrontal/orbitofrontal axis should be targeted. With the proposed technique, the deterministic tracking approach, that serves as the surgical planning data, can be refined, over-sprouting fibers are eliminated, bundle thickness is reduced in the target region, and thereby probably a more accurate targeting is facilitated. The HAMLET-driven method is meant to achieve a more objective surgical fiber display of the slMFB with deterministic tractography.

Conclusions The approach allows overlying the results of patient-specific planning from two different approaches (manual deterministic and machine learningHAMLET). HAMLET shows the slMFB as a volume and thus serves as an objective tracking corridor. It helps to refine results from deterministic tracking in the surgical workspace without interfering with any part of the standard software solution. We have now included this workflow in our daily clinical experimental work on slMFB DBS for psychiatric indications.

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The Impact of Early Corticosteroid Pretreatment Before Initiation of Chemotherapy in Patients With Primary Central Nervous System Lymphoma

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 264–272

The optimal timing of corticosteroid (CS) treatment in patients with primary central nervous system (CNS) lymphoma (PCNSL) remains controversial. While poor clinical presentation may justify early treatment with CS, this may ultimately result in reduced concentrations of chemotherapeutic agents via perturbations in the permeability of the blood-brain barrier.

OBJECTIVE: To investigate whether early CS exposure is associated with beneficial outcomes and/or reduced occurrence of adverse events as opposed to delayed/concomitant administration.

METHODS: Herein we performed a retrospective observational analysis using patients that were prospectively entered into a database. All patients whom were admitted to the University Hospital between 2009 and 2015 with newly diagnosed PCNSL were included within our study.

RESULTS: Our cohort included 50 consecutive patients diagnosed with PCNSL; of these, in 30 patients CS administration was initiated prior to chemotherapy (early), whilst in the remaining 20 patientsCS administrationwas initiated concomitantly with their chemotherapeutic regimen (concomitant).Within the early vs concomitant CS administration groups, no significant differences were observed with regard to progression-free survival (PFS) (P=.81), overall survival (OS) (P=.75), or remission (P=.68; odds ratio 0.76 and confidence interval [95%] 0.22-2.71). Critically, the timing of CS initiation was not associated with either PFS (P = .81) or PFS (P = .75).

CONCLUSION: Early CS administration was not associated with a deterioration in response to chemotherapy, PFS, or OS. As such, administration of CS prior to initiation of chemotherapy is both reasonable and safe for patients with newly diagnosed PCNSL

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Ultra-Early (<12 Hours) Surgery Correlates With Higher Rate of American Spinal Injury Association Impairment Scale Conversion After Cervical Spinal Cord Injury

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 199–203

Cervical spinal cord injury (SCI) is a devastating condition with very few treatment options. It remains unclear if early surgery correlated with conversion of American Spinal Injury Association Impairment Scale (AIS) grade A injuries to higher grades.

OBJECTIVE: To determine the optimal time to surgery after cervical SCI through retrospective analysis.

METHODS: We collected data from 48 patients with cervical SCI. Based on the time from Emergency Department (ED) presentation to surgical decompression, we grouped patients into ultra-early (decompression within 12 h of presentation), early (within 12- 24 h), and late groups (>24 h).We compared the improvement in AIS grade fromadmission to discharge, controlling for confounding factors such as AIS grade on admission, injury severity, and age. The mean time from injury to ED for this group of patients was 17 min.

RESULTS: Patients who received surgery within 12 h after presentation had a relative improvement in AIS grade from admission to discharge: the ultra-early group improved on average 1.3. AIS grades compared to 0.5 in the early group (P = .02). In addition, 88.8% of patients with an AIS grade A converted to a higher grade (AIS B or better) in the ultraearly group, compared to 38.4% in the early and late groups (P= .054).

CONCLUSION: These data suggest that surgical decompression after SCI that takes place within 12 hmay lead to a relative improved neurological recovery compared to surgery that takes place after 12 h.

 

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Early postsurgical diffusivity metrics for prognostication of long-term pain relief after Gamma Knife radiosurgery for trigeminal neuralgia

J Neurosurg 131:539–548, 2019

Gamma Knife radiosurgery (GKRS) is an important treatment modality for trigeminal neuralgia (TN). Current longitudinal assessment after GKRS relies primarily on clinical diagnostic measures, which are highly limited in the prediction of long-term clinical benefit. An objective, noninvasive, predictive tool would be of great utility to advance the clinical management of patients. Using diffusion tensor imaging (DTI), the authors’ aim was to determine whether early (6 months post-GKRS) target diffusivity metrics can be used to prognosticate long-term pain relief in patients with TN.

METHODS Thirty-seven patients with TN treated with GKRS underwent 3T MRI scans at 6 months posttreatment. Diffusivity metrics of fractional anisotropy, axial diffusivity, radial diffusivity, and mean diffusivity were extracted bilaterally from the radiosurgical target of the affected trigeminal nerve and its contralateral, unaffected nerve. Early (6 months post-GKRS) diffusivity metrics were compared with long-term clinical outcome. Patients were identified as long-term responders if they achieved at least 75% reduction in preoperative pain for 12 months or longer following GKRS.

RESULTS Trigeminal nerve diffusivity at 6 months post-GKRS was predictive of long-term clinical effectiveness, where long-term responders (n = 19) showed significantly lower fractional anisotropy at the radiosurgical target of their affected nerve compared to their contralateral, unaffected nerve and to nonresponders. Radial diffusivity and mean diffusivity, correlates of myelin alterations and inflammation, were also significantly higher in the affected nerve of long-term responders compared to their unaffected nerve. Nonresponders (n = 18) did not exhibit any characteristic diffusivity changes after GKRS.

CONCLUSIONS The authors demonstrate that early postsurgical target diffusivity metrics have a translational, clinical value and permit prediction of long-term pain relief in patients with TN treated with GKRS. Importantly, an association was found between the footprint of radiation and clinical effectiveness, where a sufficient level of microstructural change at the radiosurgical target is necessary for long-lasting pain relief. DTI can provide prognostic information that supplements clinical measures, and thus may better guide the postoperative assessment and clinical decision-making for patients with TN.

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Outcome of unilateral versus standard open midline approach for bilateral decompression in lumbar spinal stenosis: is “over the top” really better?

J Neurosurg Spine 31:236–245, 2019

In this retrospective analysis of a prospective multicenter cohort study, the authors assessed which surgical approach, 1) the unilateral laminotomy with bilateral spinal canal decompression (ULBD; also called “over the top”) or 2) the standard open bilateral decompression (SOBD), achieves better clinical outcomes in the long-term follow-up. The optimal surgical approach (ULBD vs SOBD) to treat lumbar spinal stenosis remains controversial.

METHODS The main outcomes of this study were changes in a spinal stenosis measure (SSM) symptoms score, SSM function score, and quality of life (sum score of the 3-level version of the EQ-5D tool [EQ-5D-3L]) over time. These outcome parameters were measured at baseline and at 12-, 24-, and 36-month follow-ups. To obtain an unbiased result on the effect of ULBD compared to SOBD the authors used matching techniques relying on propensity scores. The latter were calculated based on a logistic regression model including relevant confounders. Additional outcomes of interest were raw changes in main outcomes and in the Roland and Morris Disability Questionnaire from baseline to 12, 24, and 36 months.

RESULTS For this study, 277 patients met the inclusion criteria. One hundred forty-nine patients were treated by ULBD, and 128 were treated by SOBD. After propensity score matching, 128 patients were left in each group. In the matched cohort, the mean (95% CI) estimated differences between ULBD and SOBD for change in SSM symptoms score from baseline to 12 months were -0.04 (-0.25 to 0.17), to 24 months -0.07 (-0.29 to 0.15), and to 36 months -0.04 (-0.28 to 0.21). For change in SSM function score, the estimated differences from baseline to 12 months were 0.06 (-0.08 to 0.21), to 24 months 0.08 (-0.07 to 0.22), and to 36 months 0.01 (-0.16 to 0.17). Differences in changes between groups in EQ-5D-3L sum scores were estimated to be -0.32 (-4.04 to 3.40), -0.89 (-4.76 to 2.98), and -2.71 (-7.16 to 1.74) from baseline to 12, 24, and 36 months, respectively. None of the group differences between ULBD and SOBD were statistically significant.

CONCLUSIONS Both surgical techniques, ULBD and SOBD, may provide effective treatment options for DLSS patients. The authors further determined that the patient outcome results for the technically more challenging ULBD seem not to be superior to those for the SOBD even after 3 years of follow-up.

 

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Dorsal anterior cingulate cortex (ACC) deep brain stimulation (DBS): a promising surgical option for the treatment of refractory thalamic pain syndrome (TPS)

Acta Neurochirurgica (2019) 161:1579–1588

Neuroimaging evidences and previous successful case series of cingulotomy for cancer pain have disclosed the key- role of the dorsal anterior cingulate cortex (ACC) in the generation of the empathic and affective dimension of pain. The aim of this study is to assess the effectiveness and safety of ACC neuromodulation for the treatment of the thalamic pain syndrome (TPS), a chronic neuropathic disease often complicated by severe affective and emotional distress in the long term.

Method From January 2015 to April 2017, 5 patients with pure drug-refractory TPS underwent ACC deep brain stimulation (DBS) at our institution. Quantitative assessment of pain and health-related quality of life were performed 1 day before surgery and postoperatively at 6 and 18 months by using the numeric rating scale (NRS), the 36-item short-form health survey (SF-36), and the McGill pain and the EuroQol5-domain questionnaires.

Results Mean age at surgery was 56.2 years (range, 47–66). NRS score improved by 37.9% at 6 months (range, − 22.2 to − 80%) and by 35% at 18 months (range, − 11.1 to − 80%). At the last follow-up, one patient reported a relevant pain reduction (NRS 2), only complaining of mild pain poorly interfering with activities of daily living. Concomitant improvements in the McGill and EuroQol5-domain pain questionnaires, SF-36 total and sub-item scores were also noticed at each follow-up. No surgical or stimulation-related complications occurred during the study period.

Conclusions ACC DBS may be a safe and promising surgical option to alleviate discomfort and improve the overall quality of life in a patient affected by drug-resistant TPS. Further prospective, larger, and randomized studies are needed to validate these findings.

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Giant intracranial aneurysms of the posterior circulation and their relation to the brainstem: analysis of risk factors for neurological deficits

J Neurosurg 131:403–409, 2019

Giant posterior circulation aneurysms (GPCirAs) usually cause substantial mass effect on the brainstem, which may lead to neurological deficits. So far, there has been no systematic investigation of factors associated with such deficits in GPCirA. The authors aim to examine the risk factors for cranial nerve deficit (CND), motor deficit, and disability in patients with GPCirA.

METHODS Using MR images obtained in 30 patients with unruptured GPCirA, the authors examined GPCirA volume, presence of hydrocephalus or partial thrombosis (PT) of the aneurysm, and the degree of brainstem displacement mea- sured by the distance between the McRae line and the tip of the GPCirA (∆MT). They evaluated associations between these factors and neurological deficits.

RESULTS Thirty GPCirAs in 30 patients were included. The prevalence of CNDs was 50%. Patients with CNDs signifi- cantly differed from those without CNDs in terms of age (mean 51.0 years [SD 15.0 years] vs 69.0 years [SD 21.0 years], p = 0.01) and in ∆MT (median 50.7 mm [IQR 39.2–53.9 mm] vs 39.0 mm [IQR 32.3–45.9 mm], p = 0.02). The prevalence of motor deficits was 33.3%. Patients with motor deficits showed a larger ∆MT (median 50.5 mm [IQR 40.8–54.6 mm]) compared with those without (∆MT: median 39.1 mm [IQR 32.8–50.5 mm], p = 0.04). GPCirA volume was larger in patients with poor modified Rankin Scale (mRS) scores (median 14.9 cm3 [IQR 8.6–18.7 cm3]) than in those with mRS scores of 0–2 (median 6.8 cm3 [IQR 4.4–11.7 cm3], p = 0.03). After adjusting for patient age and the occurrence of hydro- cephalus or PT, the authors found that higher degrees of disability were significantly associated with aneurysm volume (OR 1.13, 95% CI 1.0–1.3; p = 0.04), but not with ∆MT. The occurrence of CND or motor deficit was not associated with any of the examined variables. There was no correlation between GPCirA volume and ∆MT (rs = 0.01, p = 0.96). The prevalence of neurological deficits did not differ between GPCirA at the basilar apex, the basilar trunk, the vertebrobasi- lar junction, or the vertebral artery.

CONCLUSIONS In this study, the neurological condition of the patients was associated only with GPCirA volume and not with the degree of brainstem displacement, the occurrence of PT or hydrocephalus, or the exact location of the GPCirA. These findings highlight the clinical relevance of GPCirA volume and suggest that factors such as brainstem displacement or PT should play less of a role when finding arguments for or against treatment of GPCirA.

 

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Withholding Perioperative Steroids in Patients Undergoing Transsphenoidal Resection for Pituitary Disease: Randomized Prospective Clinical Trial to Assess Safety

Neurosurgery, Volume 85, Issue 2, August 2019, Pages E226–E232

Perioperative steroid protocols for patients undergoing transsphenoidal surgery (TSS) for pituitary pathology vary by institution.

OBJECTIVE: To assess the safety of withholding glucocorticoids in patients undergoing TSS.

METHODS: Patients with an intact hypothalamic-pituitary-adrenal (HPA) axis undergoing TSS for a pituitary tumor at the same academic institution between 2012 and 2015 were randomized to either receive 100 mg of intravenous hydrocortisone followed by 0.5 mg of intravenous dexamethasone every 6 h for 4 doses (STER, n = 23) or to undergo surgery without steroids (NOSTER, n = 20). Postoperative cortisol levels were then used to determine the need for glucocorticoids after surgery. Data regarding postoperative cortisol levels, hospital stay length, and complications were collected.

RESULTS: Mean postoperative 8 am cortisol levels were higher in the NOSTER group compared to the STER group (745 ± 359 nmol/L and 386 ± 193 nmol/L, respectively, P = .001) and more patients were discharged on glucocorticoids in the STER group (42% vs 12%, P = .07). There was no difference in the incidence of postoperative complications, including hyperglycemia, diabetes insipidus, or permanent adrenal insufficiency. Permanent adrenal insufficiency occurred in 8% of patients.

CONCLUSION: Perioperative steroids can be safely withheld in patients with an intact HPA axis undergoing TSS. Although administration of perioperative glucocorticoids does not appear to increase the risk of complications, it may interfere with assessment of the HPA axis after surgery.

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Results of Gamma Knife anterior capsulotomy for refractory obsessive-compulsive disorder

J Neurosurg 131:376–383, 2019

Obsessive-compulsive disorder (OCD) is a severe psychiatric condition. The authors present their experience with Gamma Knife radiosurgery (GKRS) in the treatment of patients with OCD resistant to any medical therapy.

METHODS Patients with severe OCD resistant to all pharmacological and psychiatric treatments who were treated with anterior GKRS capsulotomy were retrospectively reviewed. These patients were submitted to a physical, neurological, and neuropsychological examination together with structural and functional MRI before and after GKRS treatment. Strict study inclusion criteria were applied. Radiosurgical capsulotomy was performed using two 4-mm isocenters targeted at the midputaminal point of the anterior limb of the capsule. A maximal dose of 120 Gy was prescribed for each side. Clini- cal global changes were assessed using the Clinical Global Impression (CGI) scale, Global Assessment of Functioning (GAF) scale, EQ-5D, Beck Depression Inventory (BDI), and State-Trait Anxiety Inventory (STAI). OCD symptoms were determined by the Yale–Brown Obsessive Compulsive Scale (Y-BOCS).

RESULTS Ten patients with medically refractory OCD (5 women and 5 men) treated between 2006 and 2015 were included in this study. Median age at diagnosis was 22 years, median duration of illness at the time of radiosurgery was 14.5 years, and median age at treatment was 38.8 years. Before GKRS, the median Y-BOCS score was 34.5 with a me- dian obsession score of 18 and compulsion score of 17. Seven (70%) of 10 patients achieved a full response at their last follow-up, 2 patients were nonresponders, and 1 patient was a partial responder. Evaluation of the Y-BOCS, BDI, STAI- Trait, STAI-State, GAF, and EQ-5D showed statistically significant improvement at the last follow-up after GKRS. Neurological examinations were normal in all patients at each visit. At last follow-up, none of the patients had experienced any significant adverse neuropsychological effects or personality changes.

CONCLUSIONS GKRS anterior capsulotomy is effective and well tolerated with a maximal dose of 120 Gy. It reduces both obsessions and compulsions, improves quality of life, and diminishes depression and anxiety.

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Assessment of costs in open surgery and stereotactic radiosurgery for vestibular schwannomas

J Neurosurg 131:561–568, 2019

Microsurgical resection and radiosurgery remain the most widely used interventions in the treatment of vestibular schwannomas. There is a growing demand for cost-effectiveness analyses to evaluate these two treatment modalities and delineate the factors that drive their total costs. Here, the authors evaluated specific cost drivers for mi- crosurgical and radiosurgical management of vestibular schwannoma by using the Value Driven Outcomes system avail- able at the University of Utah.

METHODS The authors retrospectively reviewed all cases involving microsurgical and radiosurgical treatment of ves- tibular schwannomas at their institution between November 2011 and September 2017. Patient and tumor characteristics, subcategory costs, and potential cost drivers were analyzed.

RESULTS The authors identified 163 vestibular schwannoma cases, including 116 managed microsurgically and 47 ad- dressed with stereotactic radiosurgery (SRS). There were significant differences between the two groups in age, tumor size, and preoperative Koos grade (p < 0.05), suggesting that indications for treatment were markedly different. Length of stay (LOS) and length of follow-up were also significantly different. Facility costs were the most significant contributor to both microsurgical and SRS groups (58.3% and 99.4%, respectively); however, physician professional fees were not spe- cifically analyzed. As expected, microsurgical treatment resulted in an average 4-fold greater overall cost of treatment than for SRS cases (p < 0.05), and there was a greater variation in costs for open cases as well. Costs remained stable over time for both open resection and SRS. Multivariable analysis showed that LOS (b = 0.7, p = 0.0001), discharge dis- position (b = 0.2, p = 0.004), nonserviceable hearing (b = 0.1, p = 0.02), and complications (b = 0.2, p = 0.005) affected cost for open surgery, whereas no specifically examined factor could be identified as driving costs for SRS.

CONCLUSIONS This analysis identified the fact that facility utilization constitutes the majority of total costs for both microsurgery and SRS treatment modalities of vestibular schwannomas. LOS, discharge disposition, nonserviceable hearing, and complications contributed significantly to the total costs for the microsurgical group, whereas none of the factors could be identified as driving total costs for the SRS group. This information may be used to establish policies and protocols to reduce facility costs, with the goal of decreasing the total costs without jeopardizing patient care.

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A modern series of subdiaphragmatic craniopharyngiomas

J Neurosurg 131:526–531, 2019

The endoscopic endonasal approach has been proposed as a primary surgical strategy for select cranio- pharyngiomas. However, those tumors that arise from the sella have not been classified with the other craniopharyn- gioma subtypes in terms of surgical nuances, intraoperative findings, and postoperative outcomes. The authors describe their experience with a select subtype of craniopharyngioma arising within the sella subjacent to the diaphragma sellae and refer to these tumors as type 0.

METHODS After obtaining IRB approval, three institutions retrospectively reviewed their data collected from 2005 to 2017. Patients eligible for inclusion in the study were those who had tumors that originated from the sella inferior to the diaphragma sellae. Demographic, clinical, radiological, surgical, and follow-up data were examined and analyzed.

RESULTS Twenty-eight patients (average age 19.3 years, range 3–60 years) were included in this study. Sixteen pa- tients (57%) were younger than 18 years of age. All patients had characteristic imaging features of an expanded sella. Seventy-five percent of the patients presented with some form of visual field deficit (89% had radiographic optic appa- ratus compression) and 39% with hypopituitarism. The average maximal tumor diameter in the axial, coronal, or sagittal plane was 3.1 cm. Gross-total resection was achieved in 82% of the patients. Twenty-one percent of patients experi- enced an iatrogenic complication, and there were only two cases (7%) of postoperative cerebrospinal fluid (CSF) leak- age. Only two patients (7%) required the use of a nasoseptal flap as part of their original reconstruction. Pathology was uniformly the adamantinomatous subtype. Postoperative objective visual outcomes were improved in 71% of the patients with visual symptoms or visual field deficits on presentation and stable in 24%. Mean follow-up was 45.1 months (range 3–120 months) with an 18% recurrence rate at a mean of 44.4 months (range 10–84 months). One patient was lost to follow-up. Thirty-six percent of patients received postoperative radiation to treat recurrence or residual tumor. Endocrine data are also presented.

CONCLUSIONS Craniopharyngiomas that originate within the sella below the diaphragma sellae are a select subtype characterized by 1) an enlarged sella, 2) an intact diaphragma sellae at surgery, and 3) an adamantinomatous pathology. These tumors can be treated transnasally without the absolute need for neurovascular flap reconstruction, as there is a low risk of CSF leakage.

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Surgical management of camptocormia in Parkinson’s disease: systematic review and meta-analysis

J Neurosurg 131:368–375, 2019

Camptocormia is a potentially debilitating condition in the progression of Parkinson’s disease (PD). It is described as an abnormal forward flexion while standing that resolves when lying supine. Although the condition is relatively common, the underlying pathophysiology and optimal treatment strategy are unclear. In this study, the authors systematically reviewed the current surgical management strategies for camptocormia.

METHODS PubMed was queried for primary studies involving surgical intervention for camptocormia in PD patients. Studies were excluded if they described nonsurgical interventions, provided only descriptive data, or were case reports. Secondarily, data from studies describing deep brain stimulation (DBS) to the subthalamic nuclei were extracted for potential meta-analysis. Variables showing correlation to improvement in sagittal plane bending angle (i.e., the vertical angle caused by excessive kyphosis) were subjected to formal meta-analysis.

RESULTS The query resulted in 9 studies detailing treatment of camptocormia: 1 study described repetitive trans-spinal magnetic stimulation (rTSMS), 7 studies described DBS, and 1 study described deformity surgery. Five studies were included for meta-analysis. The total number of patients was 66. The percentage of patients with over 50% decrease in sagittal plane imbalance with DBS was 36.4%. A duration of camptocormia of 2 years or less was predictive of better outcomes (OR 4.15).

CONCLUSIONS Surgical options include transient, external spinal stimulation; DBS targeting the subthalamic nuclei; and spinal deformity surgery. Benefit from DBS stimulation was inconsistent. Spine surgery corrected spinal imbalance but was associated with a high complication rate.

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Clinical Outcomes of Upfront Stereotactic Radiosurgery Alone for Patients With 5 to 15 Brain Metastases

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 257–263

The role of primary stereotactic radiosurgery (SRS) for patients with >4 brain metastases (BM) remains controversial.

OBJECTIVE: To compare the outcomes of patients treated with upfront SRS alone for 1, 2 to 4, and 5 to 15 BM and assess for predictors of clinical outcomes in the 5 to 15 BM group.

METHODS: A total of 478 patients treated with upfront SRS were stratified by number of lesions: 220 had 1 BM, 190 had 2 to 4 BM, and 68 patients had 5 to 15 BM. Overall survival and whole brain radiotherapy-free survival were estimated using the Kaplan–Meier method. The cumulative incidences of local failure and distant brain failure (DBF) were estimated using competing risks methodology. Clinicopathologic and dosimetric parameters were evaluated as predictors of survival and DBF in patients with 5 to 15 BM using Cox propor- tional hazards.

RESULTS: Median overall survival was 8.0, 6.3, and 4.7 mo for patients with 1, 2 to 4, and 5 to 15 BM, respectively (P = .14). One-year DBF was 27%, 44%, and 40%, respec- tively (P = .01). Salvage SRS and whole brain radiotherapy rates did not differ. Progressive extracranial disease and gastrointestinal primary were associated with poor survival while RCC primary was associated with increased risk of DBF. No evaluated dose-volume param- eters predicted for death, neurologic death or toxicity.

CONCLUSION: SRS for 5 to 15 BM is well tolerated without evidence of an associated increase in toxicity, treatment failure, or salvage therapy. Further prospective, randomized studies are warranted to clarify the role of SRS for these patients.

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Evaluation of neurosurgical implant infection rates and associated pathogens: evidence from 1118 postoperative infections

Neurosurg Focus 47 (2):E6, 2019

Various implanted materials are used in neurosurgery; however, there remains a lack of pooled data on infection rates (IRs) and infective bacteria over past decades. The goal of this study was to investigate implant infections in neurosurgical procedures in a longitudinal retrospective study and to evaluate the IRs of neurosurgically implanted materials and the distribution of pathogenic microorganisms.

METHODS A systematic literature search was conducted using PubMed and Web of Science databases for the time period between 1968 and 2018. Neurosurgical implant infections were studied in 5 subgroups, including operations or diseases, implanted materials, bacteria, distribution by country, and time periods, which were obtained from the literature and statistically analyzed. In this meta-analysis, statistical heterogeneity across studies was tested by using p values and I2 values between studies of associated pathogens. Egger’s test was used for assessing symmetries of funnel plots with Stata 11.0 software. Methodological quality was assessed to judge the risk of bias according to the Cochrane Handbook.

RESULTS A total of 22,971 patients from 227 articles satisfied the study’s eligibility criteria. Of these, 1118 cases of infection were reported, and the overall IR was 4.87%. In this study, the neurosurgical procedures or disorders with the top 3 IRs included craniotomy (IR 6.58%), cranioplasty (IR 5.89%), and motor movement disorders (IR 5.43%). Among 13 implanted materials, the implants with the top 3 IRs included polypropylene-polyester, titanium, and polyetheretherketone (PEEK), which were 8.11%, 8.15%, and 7.31%, respectively. Furthermore, the main causative pathogen was Staphylococcus aureus and the countries with the top 3 IRs were Denmark (IR 11.90%), Korea (IR 10.98%), and Mexico (IR 9.26%). Except for the low IR from 1998 to 2007, the overall implant IR after neurosurgical procedures was on the rise.

CONCLUSIONS In this study, the main pathogen in neurosurgery was S. aureus, which can provide a certain reference for the clinic. In addition, the IRs of polypropylene-polyester, titanium, and PEEK were higher than other materials, which means that more attention should be paid to them. In short, the total IR was high in neurosurgical implants and should be taken seriously.

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Emergency Department Visits After Elective Spine Surgery

Neurosurgery, Volume 85, Issue 2, August 2019, Pages E258–E265

Emergency department (ED) overuse is a costly and often neglected source of postdischarge resource utilization after spine surgery. Failing to investigate drivers of ED visits represents a missed opportunity to improve the value of care in spine patients.

OBJECTIVE: To identify the prevalence, drivers, and timing of ED visits following elective spine surgery.

METHODS: Patients undergoing elective spine surgery for degenerative disease at a major medical center were enrolled in a prospective longitudinal registry. Patient and surgery characteristics, and patient-reported outcomes were recorded at baseline and 3 mo after surgery, along with self-reported 90-d ED visits. A multivariable regression model was used to identify independent factors associated with 90-d ED visits. For a sample of patients presenting to our institution’s ED, charts were reviewed to identify the reason and time to ED postdischarge.

RESULTS: Of 2762 patients, we found a 90-d ED visit rate of 9.4%. One-third of patients presented to our institution’s ED and of these, 70% presented due to pain or medical concerns at 9 and 7 d postdischarge, respectively, with 60% presenting outside normal clinic hours. Independent risk factors for 90-d ED visits included younger age, preoperative opioid use, chronic obstructive pulmonary disorder, and more vertebral levels involved.

CONCLUSION: Nearly 10% of elective spine patients had 90-d ED visits not requiring readmission. Pain and medical concerns accounted for 70% of visits at our center, occurring within 10 d of discharge. This study provides the clinical details and a timeline necessary to guide individualized interventions to prevent unnecessary, costly ED visits after spine surgery.

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Arachnoiditis as an outcome factor for microvascular decompression in classical trigeminal neuralgia

Acta Neurochirurgica (2019) 161:1589–1598

Neurovascular conflict is considered a key element of classical trigeminal neuralgia (TN) and consequently, mi- crovascular decompression (MVD) is an effective treatment. Nevertheless, failures of MVD are described by many authors. In some patients, the arachnoid membranes surrounding the trigeminal nerve and neighbouring vessels may be thickened and adhesive. Here we analyse the impact of such focal arachnoiditis on outcome after MVD for TN.

Methods A cohort of prospectively followed patients after their MVD was reviewed for intraoperative, imaging and clinical data if findings of arachnoiditis during MVD were described. Long-term outcome assessment was the main endpoint.

Results We reviewed data from 395 MVD procedures, performed for TN from 2001 to 2014. Intraoperative evidence of focal arachnoiditis, as described by the surgeon, has been noted in 51 patients (13%). In 35 (68.6%), neuralgia was typical and in the other 17 (31.4%) it was atypical.
As expected by definition, neurovascular conflict was found in 49 interventions (96%); it was predominantly arterial in 27 (52.9%). Accompanying arachnoiditis was encountered: mild in 20 interventions (39.2%), severe in 31 (60.8%).
A successful result (BNI I or II) was achieved in 29 patients (56.9%). The other 22 patients (43.1%) had persistence or recurrence of pain. Overall KM probability of being pain free at 15 years was 72%.

Conclusions Intraoperative finding of arachnoiditis during MVD for classical trigeminal neuralgia is associated with poorer outcome than that of classical trigeminal neuralgia in general. This is particularly true for low grades of conflict.

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Noninvasive Thermal Evaluation of Ventriculoperitoneal Shunt Patency and Cerebrospinal Fluid Flow Using a Flow Enhancing Device

Neurosurgery, Volume 85, Issue 2, August 2019, Pages 240–249

While a noninvasive flow determination would be desirable in the diagnosis of cerebrospinal fluid shunt malfunction, existing studies have not yet defined a role for thermal flow detection.

OBJECTIVE: To evaluate a revised test protocol using a micropumper designed to transiently enhance flow during thermal testing to determine whether thermal detection of flow is associated with progression to shunt revision surgery.

METHODS: Eighty-two unique tests were performed in 71 shunts. The primary outcome, need for revision within 7 d of testing, was compared with results of micropumper-augmented thermal flow detection. Statistical analysis was based on blind interpretation of test results and raw temperature data recorded during testing.

RESULTS: The test was sensitive (73%) and specific (68%) in predicting need for revision, with 5.6-fold higher probability of revision when flow was not detected. Negative predictive value in our sample was 94.2%. The probability of not requiring revision increased with increasing total temperature drop. Analysis of various possible thresholds showed that the optimal temperature cutoff may be lower than suggested by the manufacturer (0.125◦C vs 0.2◦C).

CONCLUSION: This is the first study to report a strong association between thermal flow evaluation and a clinical impression that a shunt is not malfunctioning. The current recommended threshold may increase the false positive rate unnecessarily, and as clinicians gain experience with the method, they may find value in examining the temperature curves themselves. Multicenter studies are suggested to further define a role for this diagnostic test.

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Pain-free and pain-controlled survival after sectioning the nervus intermedius in nervus intermedius neuralgia: a single-institution review

J Neurosurg 131:352–359, 2019

Nervus intermedius neuralgia (NIN) or geniculate neuralgia is a rare facial pain condition consisting of sharp, lancinating pain deep in the ear and can occur alongside trigeminal neuralgia (TN). Studies on the clinical presentation, intraoperative findings, and ultimately postoperative outcomes are extremely limited. The aim of this study was to examine the clinical presentation and surgical findings, and determine pain-free survival after sectioning of the nervus intermedius (NI).

METHODS The authors conducted a retrospective chart review and survey of patients who were diagnosed with NIN at one institution and who underwent neurosurgical interventions. Pain-free survival was determined through chart review and phone interviews using a modified facial pain and quality of life questionnaire and represented as Kaplan-Meier curves.

RESULTS The authors found 15 patients with NIN who underwent microsurgical intervention performed by two sur- geons from 2002 to 2016 at a single institution. Fourteen of these patients underwent sectioning of the NI, and 8 of 14 had concomitant TN. Five patients had visible neurovascular compression (NVC) of the NI by the anterior inferior cerebellar artery in most cases where NVC was found. The most common postoperative complaints were dizziness and vertigo, diplopia, ear fullness, tinnitus, and temporary facial nerve palsy. Thirteen of the 14 patients reportedly experienced pain relief immediately after surgery. The mean length of follow-up was 6.41 years (range 8 months to 14.5 years). Overall recurrence of any pain was 42% (6 of 14), and 4 patients (isolated NIN that received NI sectioning alone) reported their pain was the same or worse than before surgery at longest follow-up. The median pain-free survival was 4.82 years ± 14.85 months. The median pain-controlled survival was 6.22 years ± 15.78 months.

CONCLUSIONS In this retrospective review, sectioning of the NI produced no major complications, such as permanent facial weakness or deafness, and was effective for patients when performed in addition to other procedures. After sectioning of the NI, patients experienced 4.8 years pain free and experienced 6.2 years of less pain than before surgery. Alone, sectioning of the NI was not effective. The pathophysiology of NIN is not entirely understood. It appears that neurovascular compression plays only a minor role in the syndrome and there is a high degree of overlap with TN.

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Nervus intermedius and the surgical management of geniculate neuralgia

J Neurosurg 131:343–351, 2019

Geniculate neuralgia (GN) is an uncommon craniofacial pain syndrome attributable to nervus intermedius (NI) dysfunction. Diagnosis and treatment can be challenging, due to the complex nature of ear sensory innervation, resulting in clinical overlap with trigeminal neuralgia (TN) and glossopharyngeal neuralgia (GPN).

METHODS A retrospective review of a prospective neurosurgical database at our institution was performed, 2000–2017, with a corresponding systematic literature review. Pain outcomes were dichotomized as unfavorable for unchanged/worsened symptoms versus favorable if improved/resolved. Eight formalin-fixed brains were examined to describe NI at the brainstem.

RESULTS Eleven patients were surgically treated for GN—9 primary, 2 reoperations. The median age was 48, 7 pa- tients were female, and the median follow-up was 11 months (range 3–143). Seven had ≥ 2 probable cranial neuralgias. NI was sectioned in 9 and treated via microvascular decompression (MVD) in 2. Five patients underwent simultaneous treatment for TN (4 MVD; 1 rhizotomy) and 5 for GPN (3 MVD; 2 rhizotomy). Eleven reported symptomatic improvement (100%); 8 initially reported complete resolution (73%). Pain outcomes at last contact were favorable in 8 (73%)—all among the 9 primary operations (89% vs 0%, p = 0.054). Six prior series reported outcomes in 111 patients.

CONCLUSIONS GN is rare, and diagnosis is confounded by symptomatic overlap with TN/GPN. Directed treatment of all possible neuralgias improved pain control in almost all primary operations. Repeat surgery seems a risk factor for an unfavorable outcome. NI is adherent to superomedial VIII at the brainstem; the intermediate/cisternal portion is optimal for visualization and sectioning.

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