1. Gallina P, Lastrucci G, Caini S, Lorenzo N Di, Porfirio B, Scollato A. Accuracy and safety of 1-day external lumbar drainage of CSF for shunt selection in patients with idiopathic normal pressure hydrocephalus. J Neurosurg. 2018:1-7. doi:10.3171/2018.6.JNS18400.
Cerebrospinal fluid shunting is the treatment of choice for idiopathic normal pressure hydrocephalus (iNPH) with a 75%–82% rate of successful outcome and 11% risk of serious adverse events. Not all patients diagnosed with iNPH are likely to benefit from shunt, and preoperative “supplemental prognostic tests” with intracranial pressure recording or CSF infusion/subtraction are recommended. External lumbar drainage (ELD) of CSF has gained wide acceptance among neurosurgeons as the best predictor of successful shunt surgery. The hypothesis underlying ELD is that prolonged drainage of a relatively large amount of CSF, more than with the spinal tap test, mimics a shunt effect.
Three to five days of external lumbar drainage of CSF is a test for ventriculoperitoneal shunt (VPS) selection in idiopathic normal pressure hydrocephalus. The accuracy and complication rates of a shorter (1-day) ELD procedure were analyzed.
Of 93 patients who underwent 1-day ELD, 3 did not complete the procedure. Of the remaining 90 patients, 2 experienced transient nerve root irritation. Twenty-four patients had negative test outcomes and 66 had positive test outcomes. Nine negative-outcome patients had intraprocedural headache, which showed 37.5% sensitivity and 100% specificity as predictors of negative 1-day ELD outcome. Sixty-eight patients (6 with negative and 62 with positive outcomes) underwent VPS insertion, which was successful in 0 and 58 patients, respectively, at 1-month follow-up.
They conclude that one-day ELD is a reliable tool in iNPH management, with low complication risk and short trial duration. The test is very consistent in predicting who will have a positive outcome with VPS placement, given the high chance of successful outcome at 1- and 12-month follow-up.
1 Figure of patient stratification
2. Wang W, Lieber S, Mathias RN, et al. The foramen lacerum: surgical anatomy and relevance for endoscopic endonasal approaches. J Neurosurg. 2018:1-12. doi:10.3171/2018.6.JNS181117.
Ten colored silicone-injected anatomical specimens were dissected using a transpterygoid approach to the foramen lacerum region in a stepwise manner. Five similar specimens were used for a comparative transcranial approach. The osseous anatomy was examined in 32 high-resolution multislice CT studies and 1 disarticulated skull.
The foramen lacerum does not represent a true foramen in the sense of an osseous channel containing neurovascular structures, but rather a gap formed by the incomplete confluence of three essential osseous structures composing the central skull base: the sphenoid bone (body and greater wing), temporal bone (petrous apex), and occipital bone (clival part). Its lower part is filled up with fibrocartilaginous tissue whereas its upper part contains the internal carotid artery.
Nice anatomic study looking at the surgical anatomy of the foramen lacerum and its adjacent structures using cadaveric dissections and imaging studies, and the authors propose several key surgical landmarks.
7 figures
3. Ahmed AK, Goodwin CR, Heravi A, et al. Predicting survival for metastatic spine disease: a comparison of nine scoring systems. Spine J. 2018;18(10):1804-1814. doi:10.1016/j.spinee.2018.03.011.
The aim of this retrospective study was to compare the ability of widespread scoring systems
to estimate both overall survival at various time points and tumor-specific survival for patients undergoing surgical treatment for metastatic spine disease in order to provide surgeons with information to determine the most appropriate scoring system.
The preoperative score for 176 patients was retrospectively calculated utilizing the Skeletal Oncology Research Group (SORG) Classic Scoring Algorithm, SORG Nomogram, original Tokuhashi, revised Tokuhashi, Tomita, original Bauer, modified Bauer, Katagiri, and van der Linden scoring systems. Univariate and multivariate Cox proportional hazard models were constructed to assess the association of patient variables with survival. Receiver operating characteristic analysis modeling was utilized.
Among all patients surgically treated for metastatic spine disease, the SORG Nomogram demonstrated the highest accuracy at predicting 30-day and 90-day survival after surgery. The original Tokuhashi was the most accurate at predicting 365-day survival.
References to the scoring systems:
Tokuhashi – Tokuhashi Y, Matsuzaki H, Toriyama S, Kawano H, Ohsaka S. Scoring system for the preoperative evaluation of metastatic spine tumor prognosis. Spine 1990;15:1110–13.
Revised Tokuhashi – Tatsui H, Onomura T, Morishita S, Oketa M, Inoue T. Survival rates of patients with metastatic spinal cancer after scintigraphic detection of abnormal radioactive accumulation. Spine 1996;21:2143–8.
Tomita – Tomita K, Kawahara N, Kobayashi T, Yoshida A, Murakami H, Akamaru T. Surgical strategy for spinal metastases. Spine 2001;26:298–306.
Original Bauer – Bauer HC, Wedin R. Survival after surgery for spinal and extremity metastases. Prognostication in 241 patients. Acta Orthop Scand 1995;66:143–6.
Modified Bauer – Leithner A, Radl R, Gruber G, Hochegger M, Leithner K, Welkerling H, et al. Predictive value of seven preoperative prognostic scoring systems for spinal metastases. Eur Spine J 2008;17:1488–95. doi:10.1007/s00586-008-0763-1.
Katagiri – Katagiri H, Takahashi M, Wakai K, Sugiura H, Kataoka T, Nakanishi K. Prognostic factors and a scoring system for patients with skeletal metastasis. J Bone Joint Surg Br 2005;87:698–703. doi:10.1302/0301-620X.87B5.15185.
Van der Linden – van der Linden YM, Dijkstra SPDS, Vonk EJA, Marijnen CAM, Leer JWH. Dutch Bone Metastasis Study Group. Prediction of survival in patients with metastases in the spinal column: results based on a randomized trial of radiotherapy. Cancer 2005;103:320–8. doi:10.1002/cncr.20756.
SORG – Paulino Pereira NR, Janssen SJ, van Dijk E, Harris MB, Hornicek FJ, Ferrone ML, et al. Development of a prognostic survival algorithm for patients with metastatic spine disease. J Bone Joint Surg Am 2016;98:1767–76. doi:10.2106/JBJS.15.00975.
7 Tables and 2 Figures with Kaplan-Meier survival curves
4. Scheitz JF, Nolte CH, Doehner W, Hachinski V, Endres M. Stroke–heart syndrome: clinical presentation and underlying mechanisms. Lancet Neurol. 2018;17(0):1109-1120. doi:10.1016/S1474-4422(18)30336-3.
This review article discusses the concept of stroke–heart syndrome (ie, cardiac manifestations induced by an ischemic stroke) as a direct consequence of brain ischemia and implies that cardiac disturbances occur after the onset of neurological deficits. Strong evidence suggests that the frequency and severity of stroke–heart syndrome peak within the first 3 days after the event. Most of these stroke-associated cardiac disturbances are transient, but a subgroup of patients show poor short-term and probably long-term outcome. Stroke–heart syndrome must be distinguished from cardiac disturbances secondary to systemic disease, such as sepsis, anemia, or poor oxygenation (panel). Distinguishing stroke–heart syndrome from concomitant or preceding acute coronary syndrome (i.e., due to coronary plaque rupture or thrombosis) can be especially challenging.
The evidence strongly suggests that the broad range of clinical presentations of stroke–heart syndrome probably originate from stroke-induced structural or functional alterations within the central autonomic network—a network of brain structures modulating physiological adaptation of cardiovascular function via regulation of the sympathovagal outflow to the heart.
Meta-analyses of functional MRI studies confirmed the insular cortex, prefrontal cortex, cingulate cortex, amygdala, hypothalamus, and hippocampus formation as important factors in the central autonomic network. Evidence suggests that sympathetic and parasympathetic cardiovascular function might be lateralized. Sympathetic activation seems to be mainly located within the prefrontal cortex, anterior cingulate cortex, left amygdala, and right anterior insular and left posterior insular cortices.
Of the brain regions aforementioned, the insular cortex is frequently affected in patients with ischemic stroke because of its blood supply by the middle cerebral artery. The insular cortex constitutes a cortical representation of interoceptive awareness and emotional processing of the current cardiovascular state (e.g., heart beat awareness). One study of 228 patients who had an MRI scan after ischemic stroke used voxel-based lesion symptom mapping to investigate whether localization of the ischemic stroke precipitated myocardial injury. Although single cardiac troponin values did not show any relation to stroke lesion location, relative dynamic changes in this biomarker concentration were statistically significantly associated with right anterior insular lesions.
The amygdala is another important region within the central autonomic network that modulates cardiovascular response to severe emotional stimuli and has a role in processing emotions such as fear and anxiety. Activity within the amygdala on ¹⁸FDG PET/CT scans of 293 participants undergoing cancer screening was associated with high perceived stress, arterial inflammation, and incidence of cardiovascular events.
Although lesion location within the central autonomic network, high and more dynamic cardiac troponin concentrations, and premorbid cardiac disease seem to be established risk factors for stroke–heart syndrome, further contributing aspects, such as sex issues, circadian rhythmicity, and epigenetic modification of stress-related genes linked to individual vulnerability to stress need to be scrutinized.
4 Figures, 1 Table
5. GBD 2016 Meningitis Collaborators. Global, regional, and national burden of meningitis, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol. 2018;17(11):1061-1082. doi:10.1016/S1474-4422(17)30299-5.
The Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2016 study estimated meningitis burden due to one of four types of cause: pneumococcal, meningococcal, Haemophilus influenzae type b, and a residual category of other causes. Cause-specific mortality estimates were generated via cause of death ensemble modelling of vital registration and verbal autopsy data that were subject to standardized data processing algorithms. Deaths were multiplied by the GBD standard life expectancy at age of death to estimate years of life lost, the mortality component of disability-adjusted life-years (DALYs).
Global meningitis deaths decreased by 21·0% from 1990 to 2016, from 403,012 to 318,400. Incident cases globally increased from 2·50 million in 1990 to 2·82 million in 2016. Meningitis mortality and incidence were closely related to Socio-demographic Index. The highest mortality rates and incidence rates were found in the peri-Sahelian countries that comprise the African meningitis belt, with six of the ten countries with the largest number of cases and deaths being located within this region. Haemophilus influenzae type b was the most common cause of incident meningitis in 1990, at 780,070 cases globally, but decreased the most (–49·1%) to become the least common cause in 2016, with 397,297 cases. Meningococcus was the leading cause of meningitis mortality in 1990, whereas other meningitis was the leading cause for both
deaths and incident cases (1·25 million) in 2016. Pneumococcus caused the largest number of years of life lived with disability (YLDs) in 2016, owing to its more severe long-term effects on survivors.
They conclude that this study estimates that the largest concentration of meningitis mortality remains in the meningitis belt, which includes 26 countries across sub-Saharan Africa—from Senegal in the west to Ethiopia in the east—but many other countries also continue to have a high burden of meningitis. Vaccine coverage should be increased and existing vaccination schedules optimized to maximize population protection. Incorporating meningitis vaccines into routine vaccination schedules and ensuring these vaccines are available and administered in more countries should also be considered.
5 Figures and 1 gigantic table.
6. Sarode DP, Demetriades AK. Surgical versus non-surgical management for type II odontoid fractures in the elderly population: a systematic review. Spine J. 2018;18(10):1921-1933. doi:10.1016/j.spinee.2018.05.017.
This systematic review and meta-analysis aims to synthesize the current published literature comparing outcomes following surgical and non-surgical interventions for type II odontoid fractures in the elderly population (≥65 years old). Surgical interventions included a variety of techniques using either anterior or posterior approaches. Non-surgical interventions included halo-vest immobilization, variations of cervical collar, or solely skeletal traction.
Twelve studies (n=1,098), all non-randomized, met eligibility criteria. All 12 included studies were non-randomized cohort studies; 10 were retrospectively performed. Methodological quality was particularly poor in the confounding, bias, and power domains of assessment. Substantial methodological and statistical heterogeneity allowed only a narrative synthesis of the primary outcomes. Overall, data on mortality at short-term follow-up appeared to favor neither surgical nor non-surgical intervention. A small favorable outcome in surgically managed patients over nonsurgically managed patients in terms of mortality at long-term follow-up was not proven conclusive because of considerable heterogeneity in study methodologies.
Although RCTs represent the gold standard, only a single 2007 report of such a study has been identified, reflecting the difficulty in performing such a trial. This interim report, however, required 20 additional patients to reach their target sample size but there has been no further publication. Contact with the authors has revealed there has been no further progress with the clinical trial since this report but dissemination of the incomplete trial results would be considered in the near future. Nevertheless, there is a distinct lack of RCTs addressing this important issue, the presence of which would greatly bolster the current evidence base. An initial assessment of frailty and medical comorbidities with suitable patients subsequently randomized to surgical or non-surgical treatment would be a practical, and clinically applicable, approach and would help in overcoming some of the issues faced in performing
such an RCT.
7. Robinson AL, Olerud C, Robinson Y. Surgical treatment improves survival of elderly with axis fracture—a national population-based multiregistry cohort study. Spine J. 2018;18(10):1853-1860. doi:10.1016/j.spinee.2018.03.021.
Utilizing the Swedish Patient Registry 1997-2014 and Swedish Cause of Death Registry 1997-2014 the authors evaluated the survival after C2 fracture according to non-surgical and surgical treatment. They included all patients treated for the primary diagnosis of C2 fracture at an age ≥70 years and receiving treatment at a health-care facility. Non-surgical treatment comprises cervical collar or halo-vest treatment. Surgical treatment was identified in the Swedish patient registry extract using the Swedish classification of procedural codes. Survival was determined
using the Kaplan-Meier method.
Of the included 3,375 elderly patients with C2 fractures (43% men, aged 83±7 years),
22% were treated surgically. Surgical treatment was assigned based on age, gender, and year of treatment. The 1-year survival of 2,618 non-surgically treated patients was 72% (n=1,856), and 81% (n=614) for the 757 surgically treated (relative risk reduction=11%). Adjusted for age, gender, comorbidity, and year of injury, surgically treated patients had greater survival than non-surgically treated patients. Among those above 88 years of age surgical treatment lost its effect on survival.
They conclude that despite the frailty of elderly patients, the morbidity of cervical external immobilization with a rigid collar seemingly weighs greater than surgical morbidity, even in octogenarians.
The commentary on this paper notes that the findings are of limited validity as the database used did not capture essential information in this setting; specifically, neurological status and specifics of co-morbidities. The commentary states that this is common theme in the use of basic national databases—the questions asked are insufficient for the answers we seek. RCTs and prospective, well-thought-out spine-specific registries are key.
8. Rajpurkar P, Irvin J, Ball RL, et al. Deep learning for chest radiograph diagnosis: A retrospective comparison of the CheXNeXt algorithm to practicing radiologists. PLOS Med. 2018;15(11):e1002686. doi:10.1371/journal.pmed.1002686.
The authors developed CheXNeXt, a convolutional neural network to concurrently detect the presence of 14 different pathologies, including pneumonia, pleural effusion, pulmonary masses, and nodules in frontal-view chest radiographs. CheXNeXt was trained and internally validated on the ChestX-ray8 dataset, with a held-out validation set consisting of 420 images, sampled to contain at least 50 cases of each of the original pathology labels.
The ChestX-ray14 dataset was used to develop the deep learning algorithm. The dataset is currently the largest public repository of radiographs, containing 112,120 frontal-view (both posteroanterior and anteroposterior) chest radiographs of 30,805 unique patients. Each image in ChestX-ray14 was annotated with up to 14 different thoracic pathology labels that were chosen based on frequency of observation and diagnosis in clinical practice.
On the validation set, the majority vote of a panel of 3 board-certified cardiothoracic specialist radiologists served as reference standard. They compared CheXNeXt’s discriminative performance on the validation set to the performance of 9 radiologists using the area under the receiver operating characteristic curve (AUC). The radiologists included 6 board-certified radiologists (average experience 12 years, range 4–28 years) and 3 senior radiology residents, from 3 academic institutions. They found that CheXNeXt achieved radiologist-level performance on 11 pathologies and did not achieve radiologist-level performance on 3 pathologies. The radiologists achieved statistically significantly higher AUC performance on cardiomegaly, emphysema, and hiatal hernia, with AUCs of 0.888, 0.911, and 0.985, respectively, whereas CheXNeXt’s AUCs were 0.831, 0.704, and 0.851, respectively. CheXNeXt performed better than radiologists in detecting atelectasis, with an AUC of 0.862, statistically significantly higher than radiologists’ AUC of 0.808; there were no statistically significant differences in AUCs for the other 10 pathologies. The average time to interpret the 420 images in the validation set was substantially longer for the radiologists (240 minutes) than for CheXNeXt (1.5 minutes).
3 Figures, 1 Table.
