Interlayer dural split technique for Chiari I malformation treatment in adult-Technical note

OBJECTIVE

To present an alternative surgical technique in treating cases of Chiari I Malformation with mild-to-moderate syringomyelia after decompressive suboccipital craniectomy: incising only the outer layer of the dura mater, then dissecting it from the inner layer without opening the latter.

PATIENTS AND METHODS

We utilized this technique in a short series of three cases who were admitted to our department for mild symptoms such as intermittent headache and dissociated sensory loss in the upper limbs, caused by a Chiari Malformation Type I. The patients were placed in the sitting position. We performed a reduced median suboccipital craniectomy and resection of the posterior arch of C1 adapted to the level of tonsil descent, from a limited superior half to complete resection. Afterward, we incised the outer dural layer, while sparing the inner one. Using a fine dissector, we then split apart the outer and inner layers to the margin of the craniectomy. Through the transparency of the inner layer and the arachnoid, the cerebellum and the medulla were visible and pulsating. An autologous fascia duraplasty was then performed.

RESULTS

The postoperative course was favorable in all cases, the patients being discharged without any deficits and with complete symptom resolution. Follow-up at 3, 6, and 12 months after surgery revealed a significant reduction in brainstem compression and syringomyelia.

CONCLUSIONS

Interlayer dural split technique can be used effectively in treating symptomatic cases of type I Chiari malformation in adults, with mild-to-moderate syringomyelia. It is less invasive than opening the dura and possibly more effective than decompressive craniectomy and C1 laminectomy alone. This technique must be validated in a larger case-control series.

[Surgical treatment of spinal cord cavernous malformations]

Cavernous malformations (CMs) of central nervous system are vascular malformations usually localized in the brain and rarely in the spinal cord. To date, these malformations are well studied. However, some problems of the management of this pathology are still unresolved. This is due to rare localization of intramedullary CMs in the spinal cord and difficult treatment of spinal pathology per se. To date, about 1000 cases of spinal CM are described in the literature. This review is devoted to natural course of disease and postoperative outcomes. These data allow getting a complete picture of modern concepts of the treatment of spinal CMs and formulating the questions requiring further discussion.

Speech Function Following Deep Brain Stimulation of the Caudal Zona Incerta: Effects of Habitual and High-Amplitude Stimulation

Purpose Deep brain stimulation (DBS) is often successful in alleviating motor symptoms of essential tremor (ET); however, DBS may also induce adverse speech effects. The caudal zona incerta (cZi) is a promising DBS target for tremor, but less is known about the consequences of cZi DBS for speech. This preliminary study examined how habitual cZi DBS and cZi stimulation at high amplitudes may affect speech function in persons with ET. Method Fourteen participants with ET were evaluated: off stimulation, on habitual cZi DBS, and with unilateral cZi stimulation at increasing stimulation amplitudes. At each stimulation condition, the participants read three 16-word sentences. Two speech-language pathologists made audio-perceptual consensus ratings of overall speech function, articulation, and voice using a visual sort and rate method. Rated functions when off stimulation, on habitual cZi DBS, and at maximal-amplitude stimulation were compared using Friedman nonparametric tests. For participants with bilateral habitual DBS (n = 5), the effects of bilateral and unilateral stimulation were described in qualitative terms. Results Habitual cZi DBS had no significant group-level effect on any of the investigated speech parameters. Maximal-amplitude stimulation had a small but significant negative effect on articulation. Participants with reduced articulatory precision (n = 9) had more medially placed electrodes than the nonaffected group (n = 5). Bilateral and unilateral left stimulation had comparable effects on speech. Conclusions Findings from this preliminary study of cZi DBS indicate that speech is generally not affected by stimulation at habitual levels. High-amplitude cZi stimulation may, however, induce adverse effects, particularly on articulation. Instances of decreased articulatory function were associated with stimulation of more medial electrode contacts, which could suggest cerebello-rubrospinal involvement.

Dynamic Fixation Techniques for the Prevention of Adjacent Segment Disease: A Retrospective Controlled Study

Study Design

Retrospective, controlled study.

Purpose

Dynamic fixation (topping-off technique) adjacent to a transforaminal lumbar interbody fusion (TLIF) level was developed to reduce the risk of adjacent segment disease (ASDi). This study was designed to compare the clinical and radiological outcomes between patients who underwent circumferential lumbar fusion (CLF) without the topping-off technique, CLF with dynamic rod constructs (DRC), and CLF with interspinous device (ISD).

Overview of Literature

Lumbar fusion can result in the re-distribution of stress, increased mobility, and increased intradiscal pressure at adjacent levels, ultimately leading to adjacent segment degeneration (ASDe) and ASDi. Dynamic fixation techniques (topping-off techniques) adjacent to vertebral fusion have been developed to reduce the risk of ASDe and ASDi because they provide a transitional zone between a caudal rigid fused segment and cephalad-mobile unfused levels.

Methods

A single-center, retrospective, controlled study was designed, including all patients who underwent CLF due to degenerative lumbar spinal disease in Hospital Clinic of Barcelona between 2012 and 2018. Three groups of patients were evaluated as per the type of topping-off technique used: CLF alone group, DRC group, and ISD group. Clinical and radiological outcomes were evaluated.

Results

A total of 117 patients were enrolled in the study. Sixty patients (51.3%) underwent CLF without dynamic stabilization, 24 (20.5%) were treated with DRC as topping-off technique, and 33 (28.5%) were treated with an ISD. A total of 12 patients (20.0%) in the CLF alone group showed ASDi at the final follow-up, compared to 1 (4.2%) in the DRC group (p=0.097) and 2 (6.1%) in the ISD group (p=0.127). The Cox regression model identified a significantly decreased risk of ASDi when a topping-off technique (DRC or ISD) was used (hazard ratio, 0.154; 95% confidence interval, 0.31–0.77).

Conclusions

Dynamic fixation adjacent to CLF was a safe and efficient procedure associated with improved clinical outcomes in patients with lumbar spine degenerative disease.

Multimodal Simulation of a Novel Device for a Safe and Effective External Ventricular Drain Placement

Background

External ventricular drain (EVD) placement is mandatory for several pathologies. The misplacement rate of the EVD varies widely in literature, ranging from 12.3 to 60%. The purpose of this simulation study is to provide preliminary data about the possibility of increasing the safety of one of the most common life-saving procedures in neurosurgery by testing a new device for EVD placement.

Methods

We used a novel guide for positioning the ventricular catheter (patent RM2014A000376). The trajectory was assessed using 25 anonymized head CT scans. The data sets were used to conduct three-dimensional computer-based and combined navigation and augmented reality-based simulations using plaster models. The data set inclusion criteria were volumetric head CT scan, without midline shift, of patients older than 18. Evans' index was used to quantify the ventricle's size. We excluded patients with slit ventricles, midline shift, skull fractures, or complex skull malformations. The proximal end of the device was tested on the cadaver.

Results

The cadaveric tests proved that a surgeon could use the device without any external help. The multimodal simulation showed Kakarla grade 1 in all cases but one (grade 2) on both sides, after right and left EVD placement. The mean Evans' index was 0.28. The geometric principles that explain the device's efficacy can be summarized by studying the properties of circumference and chord. The contact occurs, for each section considered, at the extreme points of the chord. Its axis, perpendicular to the plane tangent to the spherical surface at the entry point, corresponds to the direction of entry of the catheter guided by the instrument.

Conclusion

According to our multimodal simulation on cadavers, 3D computer-based simulation, 3D plaster modeling, 3D neuronavigation, and augmented reality, the device promises to offer safer and effective EVD placement. Further validation in future clinical studies is recommended.

Access to pediatric surgery delivered by general surgeons and anesthesia providers in Uganda: Results from 2 rural regional hospitals

BACKGROUND

Significant limitations in pediatric surgical capacity exist in low- and middle-income countries, especially in rural regions. Recent global children's surgical guidelines suggest training and support of general surgeons in rural regional hospitals as an effective approach to increasing pediatric surgical capacity.

METHODS

Two years of a prospective clinical database of children's surgery admissions at 2 regional referral hospitals in Uganda were reviewed. Primary outcomes included case volume and clinical outcomes of children at each hospital. Additionally, the disability-adjusted life-years averted by delivery of pediatric surgical services at these hospitals were calculated. Using a value of statistical life calculation, we also estimated the economic benefit of the pediatric surgical care currently being delivered.

RESULTS

From 2016 to 2019, more than 300 surgical procedures were performed at each hospital per year. The majority of cases were standard general surgery cases including hernia repairs and intussusception as well as procedures for surgical infections and trauma. In-hospital mortality was 2.4% in Soroti and 1% in Lacor. Pediatric surgical capacity at these hospitals resulted in over 12,400 disability-adjusted life-years averted/year. This represents an estimated economic benefit of 10.2 million US dollars/year to the Ugandan society.

CONCLUSION

This investigation demonstrates that lifesaving pediatric procedures are safely performed by general surgeons in Uganda. General surgeons who perform pediatric surgery significantly increase surgical access to rural regions of the country and add a large economic benefit to Ugandan society. Overall, the results of the study support increasing pediatric surgical capacity in rural areas of low- and middle-income countries through support and training of general surgeons and anesthesia providers.

The journeys of patients with trigeminal neuralgia on a background of multiple sclerosis

Aim: Multiple sclerosis (MS) is well recognized as a secondary cause for trigeminal neuralgia (TN). In this case series, we detail the management of all the patients with TN and MS (pwTNMS) presenting to a specialist unit. Materials & methods: A prospective patient database was used to extract key clinical data on pharmacological, psychometric and surgical management of 20 pwTNMS. Results: 65% of pwTNMS underwent surgical interventions for management of their pain.12/20 achieved remission periods, through surgery and/or medication. Significant improvement was noted on the global impression of change illustrated by a p < 0.001. Conclusion: pwTNMS require a multifaceted approach combining polypharmacy, surgical interventions and psychological support. Developing self-management skills is crucial if patients are to live well with pain.

Motor Evoked Potential Warning Criteria in Supratentorial Surgery: A Scoping Review

During intraoperative monitoring of motor evoked potentials (MEP), heterogeneity across studies in terms of study populations, intraoperative settings, applied warning criteria, and outcome reporting exists. A scoping review of MEP warning criteria in supratentorial surgery was conducted in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR). Sixty-eight studies fulfilled the eligibility criteria. The most commonly used alarm criteria were MEP signal loss, which was always a major warning sign, followed by amplitude reduction and threshold elevation. Irreversible MEP alterations were associated with a higher number of transient and persisting motor deficits compared with the reversible changes. In almost all studies, specificity and Negative Predictive Value (NPV) were high, while in most of them, sensitivity and Positive Predictive Value (PPV) were rather low or modest. Thus, the absence of an irreversible alteration may reassure the neurosurgeon that the patient will not suffer a motor deficit in the short-term and long-term follow-up. Further, MEPs perform well as surrogate markers, and reversible MEP deteriorations after successful intervention indicate motor function preservation postoperatively. However, in future studies, a consensus regarding the definitions of MEP alteration, critical duration of alterations, and outcome reporting should be determined.

Legacies of Neurosurgery and its Implications on Global Neurosurgery Today

Trephination, the practice of boring a hole in ones skull, is one of the oldest surgical procedures performed by and on man. Fossil records show evidence of trephined skulls on separate continents throughout ancient history. Even more remarkably, fossils show that ancient humans actually survived the procedure, some more than once. Ancient mythologies and texts provide context to the fossil record, indicating that trephination was performed some of the time for medical indications, including traumatic head injury and intractable neurological conditions. In modern day, traumatic brain injury accounts for a significant percentage of the overall global burden of disease and its incidence is disproportionately increasing in low-and-middle-income countries. In critical situations neurosurgical intervention may be indicated. The burr hole procedure, or trephination, was identified as an essential surgical procedures that all first-level hospitals should be able to perform; however, there exists a dramatic lack of access to neurosurgical specialists and care globally, especially among low-and-middle-income countries. Task-shifting/sharing is one paradigm that may be used effectively to broaden access to this life-saving procedure but it is at the moment a contested practice.

Rosette-forming glioneuronal tumor of the fourth ventricle; A case report and review of the literature

Despite mostly indolent course and favorable postoperative outcome long-term follow-up studies are needed to identify the most appropriate therapeutic strategies to minimize surgical morbidity and neurologic injury in patients with RGNT.

Clinical anatomy of the lumbar sinuvertebral nerve with regard to discogenic low back pain and review of literature

PURPOSE

Lumbar discogenic diffuse pain is still not understood. Authors describe the sinuvertebral nerve (SVN) as one possible cause. Body-donor studies are rare and controversial. Therefore, the aim was to revisit the origin, course and distribution in a body-donor study.

METHODS

Six lumbar blocks (3 female, 3 male) aged between 59 and 94 years were dissected. After removal of the back muscles, lamina, dura mater and cauda equina, the anterior vertebral venous plexus, spinal artery and SVN were exposed and evaluated.

RESULTS

43 nerves out of 48 levels could be evaluated. The origin of the SVN was constituted by two roots: a somatic and a sympathetic branch arising from the rami communicantes. In 4/48 intervertebral canals studied (8.3%), we found two SVN at the same level. In 35/48 cases, one SVN was found. In 9/48 cases, no SVN was found. The SVN had a recurrent course below the inferior vertebral notch; in the vertebral canal it showed different patterns: ascending branch (31/43, 72.1%), common branch diverging into two branches (10/43, 23.3%), double ascending branch (1/43, 2.3%) finalizing two levels above and a descending branch (1/43, 2.3%). In 12/43 cases (27.9%) the SVN had ipsilateral connections with another SVN. The distribution ended in the middle of the vertebral body supplying adjacent structures.

CONCLUSION

A thorough understanding of the anatomy of the SVN might lead to significant benefits in therapy of discogenic low back pain. We suggest blocking the SVN at the level of the inferior vertebral notch of two adjacent segments.

LEVEL OF EVIDENCE I

Diagnostic: individual cross-sectional studies with consistently applied reference standard and blinding.

Training the Next Generation of Academic Global Neurosurgeons: Experience of the Association of Future African Neurosurgeons

Introduction: Although the past decade has seen a substantial increase in African neurosurgeons' academic productivity, productivity remains low compared to their colleagues from other regions. Aspiring neurosurgeons can contribute to the academic neurosurgery workforce by taking care of less technical and time-consuming research tasks. Fortunately, global neurosurgery institutions have also made efforts to increase research exposure and scholarly output in academic global neurosurgery. The Association of Future African Neurosurgeons (AFAN) created a research incubator for aspiring academic global neurosurgeons in Africa to provide enrollees with mentorship, skills, and experience. This study assesses and reports the activities and results of the research incubator.

Methods: Aspiring academic global neurosurgeons were enrolled in the AFAN Research Incubator Program (ARIP), whose primary objective was to provide enrollees with foundational skills in all aspects of the research cycle. ARIP enrollees participated in didactic and practical activities with the aim of publishing ≥1 article and presenting ≥1 abstracts at international conferences in one year.

Results: Fifteen AFAN members aged 25.0 ± 3.0 years enrolled in ARIP: 7 (46.7%) medical students, 4 (26.7%) general practitioners, and 4 (26.7%) residents. Eleven (73.3%) were male, 6 (40.0%) were from Cameroon and 6 (40.0%) had no previous research experience. Two (13.3%) enrollees dropped out. ARIP enrollees published a total of 28 articles, and enrollees published a median of 1.0 (IQR = 2) first-author articles on neurosurgical system strengthening. Additionally, ARIP enrollees presented 20 abstracts with a median of one abstract (IQR = 3.0).

Conclusion: South-South research collaborations like ARIP can contribute to improving global neurosurgery research capacity and output. These collaborations can set up the foundations for robust research in low- and middle-income countries.

Needs of Young African Neurosurgeons and Residents: A Cross-Sectional Study

Introduction: Africa has many untreated neurosurgical cases due to limited access to safe, affordable, and timely care. In this study, we surveyed young African neurosurgeons and trainees to identify challenges to training and practice.

Methods: African trainees and residents were surveyed online by the Young Neurosurgeons Forum from April 25th to November 30th, 2018. The survey link was distributed via social media platforms and through professional society mailing lists. Univariate and bivariate data analyses were run and a P-value < 0.05 was considered to be statistically significant.

Results: 112 respondents from 20 countries participated in this study. 98 (87.5%) were male, 63 (56.3%) were from sub-Saharan Africa, and 52 (46.4%) were residents. 39 (34.8%) had regular journal club sessions at their hospital, 100 (89.3%) did not have access to cadaver dissection labs, and 62 (55.4%) had never attended a WFNS-endorsed conference. 67.0% of respondents reported limited research opportunities and 58.9% reported limited education opportunities. Lack of mentorship (P = 0.023, Phi = 0.26), lack of access to journals (P = 0.002, Phi = 0.332), and limited access to conferences (P = 0.019, Phi = 0.369) were associated with the country income category.

Conclusion: This survey identified barriers to education, research, and practice among African trainees and young neurosurgeons. The findings of this study should inform future initiatives aimed at reducing the barriers faced by this group.

State of Neurosurgical Education in Africa: A Narrative Review

BACKGROUND

There is no comprehensive report of neurosurgery postgraduate education in Africa. This narrative review aimed to map out the landscape of neurosurgery training in Africa and highlight similarities and differences in training.

METHODS

The keywords "neurosurgery," "education," and "Africa" were searched on PubMed and Google Scholar from inception to January 17, 2021. Next, a complementary hand search was conducted on Google using the keywords "neurosurgery," "residency," and the individual African countries in English and official languages. The relevant data were extracted and compiled into a narrative review.

RESULTS

A total of 76 African training programs that recruit more than 168 trainees each year were identified. Less than half (40.7%, n = 22) of African countries have at least 1 neurosurgery training program. Egypt (n = 15), Algeria (n = 14), and Nigeria (n = 10) have the highest number of training programs, whereas Algeria (0.33), Egypt (0.15), and Libya (0.15) have the highest number of training programs per 1 million inhabitants. The College of Surgeons of East, Central, and Southern Africa has 16 programs in 8 countries, whereas the West African College of Surgeons has 17 accredited programs in 3 countries. The duration of training varies between 4 and 8 years. There is limited information available in the public domain and academic literature about subspecialty fellowships in Africa.

CONCLUSIONS

This review provides prospective applicants and African and global neurosurgery stakeholders with information to advocate for increased investment in African neurosurgery training programs.

Rosette-Forming Glioneuronal Tumor of the Fourth Ventricle: A Case of Relapse Treated with Proton Beam Therapy

Rosette-forming glioneuronal tumors (RGNTs) are rare, grade I, central nervous system (CNS) tumors typically localized to the fourth ventricle. We describe a 9-year-old girl with dizziness and occipital headache. A magnetic resonance imaging (MRI) revealed a large hypodense posterior fossa mass lesion in relation to the vermis, with cystic component. Surgical resection of the tumor was performed. A RGNT diagnosis was made at the histopathological examination. During follow-up, the patient experienced a first relapse, which was again surgically removed. Eight months after, MRI documented a second recurrence at the local level. She was a candidate for the proton beam therapy (PBT) program. Three years after the end of PBT, the patient had no evidence of disease recurrence. This report underlines that, although RGNTs are commonly associated with an indolent course, they may have the potential for aggressive behavior, suggesting the need for treatment in addition to surgery. Controversy exists in the literature regarding effective management of RGNTs. Chemotherapy and radiation are used as adjuvant therapy, but their efficacy management has not been adequately described in the literature. This is the first case report published in which PBT was proposed for adjuvant therapy in place of chemotherapy in RGNT relapse.

Patient reported outcome measures in trigeminal neuralgia - A systematic review of psychometric performance

BACKGROUND

Trigeminal neuralgia (TN) is a rare condition for which there are multiple treatment options available. To date, there has been difficulty in comparing the outcomes of treatment due to the variety of patient-reported outcome measures (PROMs) and their inadequate psychometric testing. The aim of this review was to assess the psychometric properties of PROMs used to date in TN and make recommendations for their use in future studies.

METHODS

Five electronic databases (MEDLINE, EMBASE, CINAHL Plus, PsycINFO, Health and Psychosocial Instruments) were searched for studies assessing the development of PROMs or their psychometric properties in TN studies. The records obtained were assessed independently by two reviewers for their methodological quality, following guidance from the Consensus-based Standards for the selection of Health Measurement Instruments (COSMIN).

RESULTS

Six studies were identified and information on five PROMs (Brief Pain Inventory Facial (BPI-F), Visual Analogue Scale (VAS), Barrow Neurology Institute Pain Scale (BNI-PS), Penn Facial Pain Scale-Revised (Penn-FPS-R) and Trigeminal Neuralgia Quality of Life Score) were retrieved. The Penn-FPS-R demonstrated moderate quality evidence for sufficient content validity. The BPI-F showed moderate evidence for sufficient internal consistency and structural validity but low evidence for inconsistent content validity. The Trigeminal Neuralgia Quality of Life score showed very low-quality evidence for insufficient content validity, structure validity and responsiveness. No evidence was found on the assessment of any psychometric properties of the VAS and BNI-PS in TN.

CONCLUSION

There is limited evidence of the psychometric performance of patient-reported outcomes for TN and recommendations for their inclusion in future studies cannot be made. The validation of PROMs in TN studies should be a priority in this field of research.

SIGNIFICANCE

This review highlights the knowledge gap in the field of psychometrics of patient reported outcomes measures in the field of TN. Given the unavailability of an objective outcome measure for pain or health related quality of life, psychometrically sound PROMs are essential for assessing medical and surgical treatment outcomes in TN.

Evolution of the stroke paradigm: A review of delayed recanalization

While the time window for reperfusion after ischemic stroke continues to increase, many patients are not candidates for reperfusion under current guidelines that allow for reperfusion within 24 h after last known well time; however, many case studies report favorable outcomes beyond 24 h after symptom onset for both spontaneous and medically induced recanalization. Furthermore, modern imaging allows for identification of penumbra at extended time points, and reperfusion risk factors and complications are becoming better understood. Taken together, continued urgency exists to better understand the pathophysiologic mechanisms and ideal setting of delayed recanalization beyond 24 h after onset of ischemia.

Posterior Fossa Decompression and Duraplasty with and without Arachnoid Preservation for the Treatment of Adult Chiari Malformation Type 1: A Systematic Review and Meta-Analysis

BACKGROUND

The best surgical treatment for adult Chiari malformation type 1 remains widely debated.

OBJECTIVE

This study aimed to assess the efficacy of posterior fossa decompression and duraplasty with arachnoid preservation compared with arachnoid dissection for the treatment of adult Chiari malformation type 1.

METHODS

Two reviewers (M.O.-G. and M.A.) performed a PubMed, MEDLINE, and Embase literature search using the following terms: ("Chiari" OR "Chiari 1") AND ("duraplasty" OR "arachnoid preservation" OR "arachnoid spar∗" OR "posterior fossa surgery" OR "posterior fossa decompression" OR "foramen magnum decompression"). Studies assessing the efficacy of posterior fossa decompression with duraplasty for the treatment of patients aged >18 years with Chiari malformation type 1 were included. Case reports with <10 patients, editorials, and non-English studies were excluded.

RESULTS

Of 195 studies identified, 24 were included for meta-analysis. In the 1006 participants, there was no difference in postoperative clinical or radiologic improvement between the 2 techniques. Patients who underwent posterior fossa decompression with duraplasty and arachnoid dissection had a greater prevalence of total complications (0.20, 95% confidence interval [CI], 0.13-0.29 vs. 0.09, 95% CI, 0.05-0.14; Q = 6.47; P = 0.01) and cerebrospinal fluid-related complications (0.15, 95% CI, 0.10-0.22 vs. 0.05, 95% CI, 0.02-0.12; Q = 4.88; P = 0.03) compared with arachnoid preservation. Furthermore, the prevalence of reoperation in the arachnoid dissection group was 25 times greater than in the arachnoid preservation group (0.08, 95% CI, 0.06-0.10 vs. 0.003, 95% CI, 0.00-0.02; Q = 10.73; P > 0.001).

CONCLUSIONS

Posterior fossa decompression and duraplasty with arachnoid preservation is a beneficial technique to treat Chiari malformation type 1 and reduces the risk of complications, particularly cerebrospinal fluid-related complications and the rate of reoperation.

The features of the typical traumatic brain injury patient in the ICU are changing: what will this mean for the intensivist?

PURPOSE OF REVIEW

To describe the key features and epidemiology of traumatic brain injury (TBI) and how they may be changing, with an emphasis on how this may affect care in the intensive care unit.

RECENT FINDINGS

TBI has been traditionally perceived as occurring mainly in a younger, predominantly male population injured in high velocity motor vehicle crashes or assaults. However, there are an increasing number of patients over 65 years who have sustained a TBI secondary to low velocity falls. Considering the effects of frailty, comorbidities and extracranial injuries is important when making management decisions. Mild TBI comprises a third of those admitted and as a significant proportion may have poor outcomes secondary to their TBI they should be assessed to ensure appropriate follow-up. Multimodal monitoring may offer a way in the future to offer more personalised management to this very complex and heterogeneous patient group.

SUMMARY

This review highlights the urgent need to develop more age-inclusive TBI consensus management guidelines aimed at improving short- and long-term outcomes for the large and growing TBI population. Being elderly does not necessarily portend a poor outcome, and more research is needed to better triage, guide management and prognosticate on these patients.

Occipital-Cervical Fusion and Ventral Decompression in the Surgical Management of Chiari-1 Malformation and Syringomyelia: Analysis of Data From the Park-Reeves Syringomyelia Research Consortium

BACKGROUND

Occipital-cervical fusion (OCF) and ventral decompression (VD) may be used in the treatment of pediatric Chiari-1 malformation (CM-1) with syringomyelia (SM) as adjuncts to posterior fossa decompression (PFD) for complex craniovertebral junction pathology.

OBJECTIVE

To examine factors influencing the use of OCF and OCF/VD in a multicenter cohort of pediatric CM-1 and SM subjects treated with PFD.

METHODS

The Park-Reeves Syringomyelia Research Consortium registry was used to examine 637 subjects with cerebellar tonsillar ectopia ≥ 5 mm, syrinx diameter ≥ 3 mm, and at least 1 yr of follow-up after their index PFD. Comparisons were made between subjects who received PFD alone and those with PFD + OCF or PFD + OCF/VD.

RESULTS

All 637 patients underwent PFD, 505 (79.2%) with and 132 (20.8%) without duraplasty. A total of 12 subjects went on to have OCF at some point in their management (PFD + OCF), whereas 4 had OCF and VD (PFD + OCF/VD). Of those with complete data, a history of platybasia (3/10, P = .011), Klippel-Feil (2/10, P = .015), and basilar invagination (3/12, P < .001) were increased within the OCF group, whereas only basilar invagination (1/4, P < .001) was increased in the OCF/VD group. Clivo-axial angle (CXA) was significantly lower for both OCF (128.8 ± 15.3°, P = .008) and OCF/VD (115.0 ± 11.6°, P = .025) groups when compared to PFD-only group (145.3 ± 12.7°). pB-C2 did not differ among groups.

CONCLUSION

Although PFD alone is adequate for treating the vast majority of CM-1/SM patients, OCF or OCF/VD may be occasionally utilized. Cranial base and spine pathologies and CXA may provide insight into the need for OCF and/or OCF/VD.

Tractography for Subcortical Resection of Gliomas Is Highly Accurate for Motor and Language Function: ioMRI-Based Elastic Fusion Disproves the Severity of Brain Shift

Simple Summary

Tractography enables the visualization of eloquent white matter pathways. Inaccuracies due to brain shift might occur intraoperatively. The aim of this study was to evaluate the impact of intraoperative magnetic resonance imaging (MRI)-based elastic fusion on preoperative tractography for subcortical resection of gliomas. We confirmed the high accuracy of tractography during the whole course of surgery.

Abstract

When using preoperative tractography intraoperatively, inaccuracies due to brain shift might occur. Intraoperative tractography is rarely performed. Elastic fusion (EF) is a tool developed to compensate for brain shift, gravity, and tissue resection based on intraoperative images. Our hypothesis was that preoperative tractography is accurate and adjustments of tractography by intraoperative magnetic resonance imaging (ioMRI)-based EF (IBEF) compensate for brain shift. Between February 2018 and June 2019, 78 patients underwent eloquent (46 motor, 32 language) glioma resection in our department using intraoperative MRI. Mean distances between the resection cavity and tractography were analyzed and correlated with clinical outcomes. The mean ± standard deviation (range) distance after the application of IBEF was 5.0 ± 2.9 mm (0–10 mm) in patients without surgery-related motor deficits compared with 1.1 ± 1.6 mm (0–5 mm) in patients who showed new permanent surgery-related motor deficits postoperatively (p < 0.001). For language, the distance was 0.7 ± 1.2 mm (0–2 mm) in patients with new permanent deficits compared with 3.1 ± 4.5 mm (0–14 mm) in patients without new permanent surgery-related language deficits (p = 0.541). Preoperative tractography corrected by IBEF for subcortical resection of gliomas is highly accurate. However, at least for such subcortical anatomy, the severity of brain shift was considerably overestimated in the past.

Safety and Efficacy of Endovascular Therapy for Blood Blister-Like Aneurysms: Willis Covered Stents and Double Stents Assistant Coils-A Single Center Cohort Study

Objective: To summarize and discuss the application of Willis covered stents (WCSs) and double stent-assisted coils in the treatment of blood blister-like aneurysms (BBAs).

Materials and Methods: Thirty-two patients with BBAs treated from January 2015 to October 2020 were included in the study. Among them, 18 were treated using WCSs and 14 using double stents-assisted coils. The indications for treatment, perioperative findings, and postoperative follow-up results were collected and analyzed.

Results: All 32 patients had successful stent deployments. Complete aneurysm occlusion was achieved in all 18 patients treated with WCSs immediately. WCS-related adverse events included 2 cases of mild vasospasm and 4 aggressive procedure-related vasospasms during WCS deployment, a case of dissection after WCS deployment, and 1 death due to ipsilateral temporal lobe rebleeding at the sixth day after WCS deployment. In patients treated with double stent-assisted coils, there were 3 cases of neck remnants, 1 acute occlusion of the ipsilateral MCA branch, and 4 mild procedure-related intraoperative vasospasms. The mean follow-up period was 4.2±1.6 months (range 3–6 months). Follow-up imaging data were available for 25 patients (78.1%). In the first postoperative angiographic follow-up, all BBAs were completely occluded. Mild asymptomatic stent stenosis was observed in 3 patients treated with WCSs. Follow-up examination at 6 months after the employment of WCSs showed that the modified Rankin score (mRs) was 0 in 6 patients, 1 in 5 patients, 2 in 3 patients, 3 in 1 patient, 4 in 2 patients, and 6 in 1 patient. After treatment with double stents-assisted coils, the mRs was 0 in 4 patients, 1 in 5 patients, 2 in 3 patients, and 4 in 2 patients.

Conclusions: WCSs and double stent-assisted coils for the treatment of BBAs are both safe and efficient. WCSs provide a higher rate of immediate occlusion; however, there was no significant difference in the long term.

Comparison of clinical and histopathological characteristics of short-term progressive and non-progressive blood blister-like aneurysms

BACKGROUND

Many blood blister aneurysms (BBAs) have been documented with a rapid progression history in repeated angiography. The underlying mechanism and clinical significance remained elusive. This current study aims to clarify the clinical and histopathological differences between short-term progressive BBA and non-progressive BBAs.

METHODS AND MATERIALS

Eighty-one patients with BBAs were consecutively included for this single-center retrospective analysis. Clinical and radiological data on these patients were retrieved from 2017 to 2019. BBAs were defined as either progressive or non-progressive based on observed growth based on repeated imaging. Histopathological examinations of a saccular aneurysm, a progressive BBA, and a non-progressive BBA were conducted using representative aneurysm samples.

RESULTS

Among all enrolled patients, 26 of the them were identified with progressive BBAs, while the other 55 with non-progressive BBAs. Progressive BBAs were diagnosed significantly earlier in angiography (3.36 ± 0.61 vs. 6.53 ± 1.31 days, p < 0.05) and showed a higher presence rate of daughter sacs (61.5 vs. 38.2%, p < 0.05). Three different progression patterns were identified. BBAs that developed daughter sac enlargement are diagnosed significantly later than BBAs exhibiting other progression patterns. Patients with progressive and non-progressive BBAs exhibited similar overall clinical outcomes and incidence for complications. For patients with non-progressive BBAs, microsurgery appears to be inferior to endovascular treatment, while for patients with progressive BBAs, the short-term outcomes between microsurgery and endovascular treatment were identical. Histopathological analysis revealed that both subtypes shared a similar pseudoaneurysms structure, but non-progressive BBAs had more histologically destructed aneurysm wall with less remnant fibrillar collagen in adventitia.

CONCLUSIONS

Progressive and non-progressive BBAs may not be distinct pathological lesions but represent different stages during the BBA development. Early intervention, regardless of treatment methods, is recommended for salvageable patients with progressive BBAs, but microsurgery should be performed with caution for non-progressive BBAs due to increased surgical risk.

Type I Chiari Malformation Without Concomitant Bony Instability: Assessment of Different Surgical Procedures and Outcomes in 73 Patients

OBJECTIVE

Posterior fossa decompression is the treatment of choice in type 1 Chiari malformation (CM-1) without bony instability. Although surgical fixation has been recommended by a few authors recently, comparative studies to evaluate these treatment strategies using objective outcome tools are lacking.

METHODS

Seventy-three patients with pure CM-1 (posterior fossa bony decompression [PFBD], n = 21; posterior fossa bony and dural decompression [PFBDD], n = 40; and posterior fixation [PF], n = 12) underwent a postoperative outcome assessment using Chicago Chiari Outcome Score (CCOS). Logistic regression analysis detected predictors of an unfavorable outcome.

RESULTS

Minimally symptomatic patients generally underwent a PFBD while most of the clinically severe patients underwent a PFBDD (p = 0.049). The mean CCOS score at discharge was highest in the PF (12.0 ± 1.41) and lowest in PFBDD group (10.98 ± 1.73, p = 0.087). Patients with minimal preoperative clinical disease severity (adjusted odds ratio [AOR], 4.58; 95% confidence interval [CI], 1.29-16.31) and PFBDD (AOR, 7.56; 95% CI, 1.70-33.68) represented risks for an unfavorable short-term postoperative outcome. Though long-term outcomes (CCOS) did not differ among the 3 groups (p = 0.615), PFBD group showed the best long-term improvements (mean follow-up CCOS, 13.71 ± 0.95), PFBDD group improved to a comparable degree despite a poorer short-term outcome while PF had the lowest scores. Late deteriorations (n = 3, 4.1%) occurred in the PFBDD group.

CONCLUSION

Minimally symptomatic patients and PFBDD predict a poor short-term postoperative outcome. PFBD appears to be a durable procedure while PFBDD group is marred by complications and late deteriorations. PF does not provide any better results than posterior fossa decompression alone in the long run.

Low Back Pain in Adolescent and Geriatric Populations

Spinal pain is the most common form of musculoskeletal pain. Chronic low back pain may contain nociceptive, neuropathic, and central components. Children are at risk of developing spinal pain. An increasing proportion of children develop low back pain as they become adolescents. In most adolescents, no specific diagnosis is identified. Psychological factors play a role in adolescents with back pain. Lumbar spinal stenosis causes neurogenic claudication in older patients. Magnetic resonance imaging is the best radiographic technique to detect nerve compression. Surgical decompression with or without fusion may offer greater short-term benefit but may not be significantly better than medical therapy.

An exploratory qualitative study of the prevention of road traffic collisions and neurotrauma in India: perspectives from key informants in an Indian industrial city (Visakhapatnam)

BACKGROUND

Despite current preventative strategies, road traffic collisions (RTCs) and resultant neurotrauma remain a major problem in India. This study seeks to explore local perspectives in the context within which RTCs take place and identify potential suggestions for improving the current status.

METHODS

Ten semi-structured interviews were carried out with purposively selected key informants from the city of Visakhapatnam, Andhra Pradesh. Participants were from one of the following categories: commissioning stakeholders; service providers; community or local patient group/advocacy group representatives. Transcripts from these interviews were analysed qualitatively using the Framework Method.

RESULTS

Participants felt RTCs are a serious problem in India and a leading cause of neurotrauma. Major risk factors identified related to user behaviour such as speeding and not using personal safety equipment, and the user state, namely drink driving and underage driving. Other reported risk factors included poor infrastructure, moving obstacles on the road such as other vehicles, pedestrians and animals, overloaded vehicles and substandard safety equipment. Participants discussed how RTCs affect not only the health of the casualty, but are also a burden to the healthcare system, families, and the national economy. Although there are ongoing preventative strategies being carried out by both the government and the community, challenges to successful prevention emerged from the interviews which included resource deficiencies, inconsistent implementation, lack of appropriate action, poor governance, lack of knowledge and the mindset of the community and entities involved in prevention. Recommendations were given on how prevention of RTCs and neurotrauma might be improved, addressing the areas of education and awareness, research, the pre-hospital and trauma systems, enforcement and legislation, and road engineering, in addition to building collaborations and changing mindsets.

CONCLUSIONS

RTCs remain a major problem in India and a significant cause of neurotrauma. Addressing the identified gaps and shortfalls in current approaches and reinforcing collective responsibility towards road safety would be the way forward in improving prevention and reducing the burden.

Validated specialty-specific models for multi-disciplinary microsurgery training laboratories: a systematic review

BACKGROUND

Laboratory simulation is increasingly important for teaching microsurgical skills. Training microsurgeons of different specialties within the same simulation laboratory increases efficiency of resource use. For maximal benefit, simulations should be available for trainees to practice specialty-specific, higher-order skills. Selection of appropriate simulations requires knowledge of the efficacy and validity of the numerous described laboratory models. Here we present a systematic review of validated training models that may serve as useful adjuncts to achieving competency in specialty elements of microsurgery, and appraise the evidence behind them.

METHODS

In setting up a multi-disciplinary microsurgery training course, we performed a systematic review according to preferred reporting items for systematic reviews and meta-analyses guidelines. EMBASE, MEDLINE, Cochrane and PubMed databases were searched for studies describing validated, microscope-based, specialty-specific simulations, and awarded a level of evidence and level of recommendation based on a modified Oxford Centre for Evidence-Based Medicine classification.

RESULTS

A total of 141 papers describing specialty-specific microsimulation models were identified, 49 of which included evidence of validation. Eleven were in the field of neurosurgery, 21 in otolaryngology/head and neck surgery, two in urology/gynaecology and 15 plastic and reconstructive surgery. These papers described synthetic models in 19 cases, cadaveric animals in 10 cases, live animals in 12 cases and human cadaveric material in 10 cases.

CONCLUSION

Numerous specialty-specific models for use in the microscope laboratory are available, but the quality of evidence for them is poor. Provision of models that span numerous specialties may encourage use of a microscope lab whilst still enabling more specific skills training over a 'one-size-fits-all' approach.

Mapping Global Neurosurgery Research Collaboratives: A Social Network Analysis of the 50 Most Cited Global Neurosurgery Articles

Social network analysis of bibliometric data evaluates the relationships between the articles, authors, and themes of a research niche. The network can be visualized as maps composed of nodes and links. This study aimed to identify and evaluate the relationships between articles, authors, and keywords in global neurosurgery. The authors searched global neurosurgery articles on the Web of Science database from inception to June 18, 2020. The 50 most cited articles were selected and their metadata (document coupling, co-authorship, and co-occurrence) was exported. The metadata were analyzed and visualized with VOSViewer (Centre for Science and Technology Studies, Leiden University, The Netherlands). The articles were published between 1995 and 2020 and they had a median of 4.0 (interquartile range [IQR] = 5.0) citations. There were 5 clusters in the document coupling and 10 clusters in the co-authorship analysis. A total of 229 authors contributed to the articles and Kee B. Park contributed the most to articles (14 publications). Backward citation analysis was organized into 4 clusters and co-occurrence analysis into 7 clusters. The most common themes were pediatric neurosurgery, neurotrauma, and health system strengthening. The authors identified trends, contributors, and themes of highly cited global neurosurgery research. These findings can help establish collaborations and set the agenda in global neurosurgery research.

Validating machine learning approaches for prediction of donor related complication in microsurgical breast reconstruction: a retrospective cohort study

Autologous reconstruction using abdominal flaps remains the most popular method for breast reconstruction worldwide. We aimed to evaluate a prediction model using machine-learning methods and to determine which factors increase abdominal flap donor site complications with logistic regression. We evaluated the predictive ability of different machine learning packages, reviewing a cohort of breast reconstruction patients who underwent abdominal flaps. We analyzed 13 treatment variables for effects on the abdominal donor site complication rates. To overcome data imbalances, random over sampling example (ROSE) method was used. Data were divided into training and testing sets. Prediction accuracy, sensitivity, specificity, and predictive power (AUC) were measured by applying neuralnet, nnet, and RSNNS machine learning packages. A total of 568 patients were analyzed. The supervised learning package that performed the most effective prediction was neuralnet. Factors that significantly affected donor-related complication was size of the fascial defect, history of diabetes, muscle sparing type, and presence or absence of adjuvant chemotherapy. The risk cutoff value for fascial defect was 37.5 cm². High-risk group complication rates analyzed by statistical method were significant compared to the low-risk group (26% vs 1.7%). These results may help surgeons to achieve better surgical outcomes and reduce postoperative burden.

The dataset on the clipped cerebral aneurysm and their radiological findings in three-dimensional computed tomography, time-of-flight magnetic resonance angiography (TOF-MRA), and Pointwise Encoding Time Reduction with Radial Acquisition (PETRA)-MRA

These data present the 141 intracranial arterial branches' visibilities near the 72 cerebral aneurysms in postoperative 58 patients treated with titanium or cobalt-chromium-nickel-molybdenum (CCNM) alloy clips. The visibilities were evaluated using time-of-flight magnetic resonance angiography (TOF-MRA), pointwise encoding time reduction with radial acquisition (PETRA)-MRA, which uses MRA with ultrashort echo time (UTE-MRA) and subtraction technique between saturated and non-saturated images, and three-dimensional computed tomography angiography (3DCTA). We retrospectively acquired the data from the medical records of Suwa Red Cross Hospital. Each method's appearance was compared, and associations between visibility on PETRA-MRA, arterial diameter, clip numbers, clip shapes, clip materials, and amounts of hematoma were summarized. Our article on PETRA-MRA's usefulness for proximal and branched arteries evaluation after cerebral aneurysm clipping [1] was based on these data. This dataset would be useful for reference value for other neurosurgeons or radiologists for further analysis on PETRA-MRA and another UTE-MRA like SILENT-MRA after cerebral aneurysm clipping.

Pharmacological and non-pharmacological treatment approaches to chronic lumbar back pain

Low back pain is a common and important cause of disability. Chronic pain increases disability and cost. In this review, we discuss pharmacological and non-pharmacological treatment approaches for chronic low back pain in the light of current data and guidelines.

Association of the FGFR1 mutation with spontaneous hemorrhage in low-grade gliomas in pediatric and young adult patients

OBJECTIVE

The authors aimed to investigate genetic alterations in low-grade gliomas (LGGs) in pediatric and young adult patients presenting with spontaneous hemorrhage.

METHODS

Patients younger than 30 years of age with a pathological diagnosis of World Health Organization (WHO) grade I or II glioma and who had undergone treatment at the authors' institution were retrospectively examined. BRAF V600E, FGFR1 N546/K656, IDH1 R132, IDH2 R172, and KIAA1549-BRAF (K-B) fusion genetic alterations were identified, and the presence of spontaneous tumoral hemorrhage was recorded.

RESULTS

Among 66 patients (39 with WHO grade I and 27 with grade II tumors), genetic analysis revealed K-B fusion in 18 (27.3%), BRAF V600E mutation in 14 (21.2%), IDH1/2 mutation in 8 (12.1%), and FGFR1 mutation in 4 (6.1%). Spontaneous hemorrhage was observed in 5 patients (7.6%); 4 of them had an FGFR1 mutation and 1 had K-B fusion. Univariate analysis revealed a statistically significant association of an FGFR1 mutation and a diencephalic location with spontaneous hemorrhage. Among 19 diencephalic cases including the optic pathway, hypothalamus, and thalamus, an FGFR1 mutation was significantly associated with spontaneous hemorrhage (p < 0.001). Four FGFR1 mutation cases illustrated the following results: 1) a 2-year-old female with pilomyxoid astrocytoma (PMA) harboring the FGFR1 K656E mutation presented with intraventricular hemorrhage (IVH); 2) a 6-year-old male with PMA harboring FGFR1 K656E and D652G mutations presented with intratumoral hemorrhage (ITH); 3) a 4-year-old female with diffuse astrocytoma harboring FGFR1 K656M and D652G mutations presented with IVH; and 4) a young adult patient with pilocytic astrocytoma with the FGFR1 N546K mutation presented with delayed ITH and IVH after 7 years of observation.

CONCLUSIONS

Although the mechanism remains unclear, the FGFR1 mutation is associated with spontaneous hemorrhage in pediatric and young adult LGG.

Intraoperative MRI for Brain Tumors

INTRODUCTION

The use of intraoperative imaging has been a critical tool in the neurosurgeon's armamentarium and is of particular benefit during tumor surgery. This article summarizes the history of its development, implementation, clinical experience and future directions.

METHODS

We reviewed the literature focusing on the development and clinical experience with intraoperative MRI. Utilizing the authors' personal experience as well as evidence from the literature, we present an overview of the utility of MRI during neurosurgery.

RESULTS

In the 1990s, the first description of using a low field MRI in the operating room was published describing the additional benefit provided by improved resolution of MRI as compared to ultrasound. Since then, implementation has varied in magnetic field strength and in configuration from floor mounted to ceiling mounted units as well as those that are accessible to the operating room for use during surgery and via an outpatient entrance to use for diagnostic imaging. The experience shows utility of this technique for increasing extent of resection for low and high grade tumors as well as preventing injury to important structures while incorporating techniques such as intraoperative monitoring.

CONCLUSION

This article reviews the history of intraoperative MRI and presents a review of the literature revealing the successful implementation of this technology and benefits noted for the patient and the surgeon.

Virtual Connections: Improving Global Neurosurgery Through Immersive Technologies

The field of neurosurgery has always been propelled by the adoption of novel technologies to improve practice. Although advancements have occurred in the diagnosis, treatment, and long-term outcomes of patients, these have not translated to global patient benefit. Up to five million people each year do not have access to safe and affordable neurosurgical interventions, and those in low- and middle-income countries (LMICs) are disproportionately affected. Current approaches to increase neurosurgical capacity are unlikely to meet the UN Sustainable Development Goals target by 2030, and many of the most successful programs have been disrupted by the travel restrictions of the COVID-19 pandemic. There is therefore a pressing need for creative virtual solutions. An area of growing relevance is the use of immersive technologies: virtual reality (VR) and augmented reality (AR). AR allows additional information to be superimposed onto the surgeon's visual field, thus enhancing intra-operative visualization. This can be used for remote tele-proctoring, whereby an experienced surgeon can virtually assist with a procedure regardless of geographical location. Expert guidance can therefore be given to both neurosurgical trainees and non-neurosurgical practitioners, further facilitating the growing practice of neurosurgical task-shifting in LMICs. VR simulation is another useful tool in remote neurosurgical training, with the potential to reduce the learning curve of complex procedures whilst conserving supplies in low-resource settings. The adoption of immersive technologies into practice is therefore a promising approach for achieving global neurosurgical equity, whilst adapting to the long-term disruptions of the pandemic.

Use of a convolutional neural network to identify infarct core using computed tomography perfusion parameters

Purpose

Computed tomography perfusion (CTP) is used to diagnose ischemic strokes through contralateral hemisphere comparisons of various perfusion parameters. Various perfusion parameter thresholds have been utilized to segment infarct tissue due to differences in CTP software and patient baseline hemodynamics. This study utilized a convolutional neural network (CNN) to eliminate the need for non-universal parameter thresholds to segment infarct tissue.

Methods

CTP data from 63 ischemic stroke patients was retrospectively collected and perfusion parameter maps were generated using Vitrea CTP software. Infarct ground truth labels were segmented from diffusion-weighted imaging (DWI) and CTP and DWI volumes were registered. A U-net based CNN was trained and tested five separate times using each CTP parameter (cerebral blood flow (CBF), cerebral blood volume (CBV), time-to-peak (TTP), mean-transit-time (MTT), delay time). 8,352 infarct slices were utilized with a 60:30:10 training:testing:validation split and Monte Carlo cross-validation was conducted using 20 iterations. Infarct volumes were reconstructed following segmentation from each CTP slice. Infarct spatial and volumetric agreement was compared between each CTP parameter and DWI.

Results

Spatial agreement metrics (Dice coefficient, positive predictive value) for each CTP parameter in predicting infarct volumes are: CBF=(0.67, 0.76), CBV=(0.44, 0.62), TTP=(0.60, 0.67), MTT=(0.58, 0.62), delay time=(0.57, 0.60). 95% confidence intervals for volume differences with DWI infarct are: CBF=14.3±11.5 mL, CBV=29.6±21.2 mL, TTP=7.7±15.2 mL, MTT=-10.7±18.6 mL, delay time=-5.7±23.6 mL.

Conclusions

CBF is the most accurate CTP parameter in segmenting infarct tissue. Segmentation of infarct using a CNN has the potential to eliminate non-universal CTP contralateral hemisphere comparison thresholds.

Superiority of living animal models in microsurgical training: beyond technical expertise

Background

Many studies are investigating the role of living and nonliving models to train microsurgeons. There is controversy around which modalities account for the best microsurgical training. In this study, we aim to provide a systematic literature review of the practical modalities in microsurgery training and compare the living and nonliving models, emphasizing the superiority of the former. We introduce the concept of non-technical skill acquisition in microsurgical training with the use of living laboratory animals in the context of a novel proposed curriculum.

Methods

A literature search was conducted on PubMed/Medline and Scopus within the past 11 years based on a combination of the following keywords: “microsurgery,” “training,” “skills,” and “models.” The online screening process was performed by two independent reviewers with the Covidence tool. A total of 101 papers was identified as relevant to our study. The protocol was reported in line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement.

Results

Living models offer the chance to develop both technical and non-technical competencies (i.e., leadership, situation awareness, decision-making, communication, and teamwork). Prior experience with ex vivo tissues helps residents consolidate basic skills prior to performing more advanced techniques in the living tissues. Trainees reported a higher satisfaction rate with the living models.

Conclusions

The combination of living and nonliving training microsurgical models leads to superior results; however, the gold standard remains the living model. The validity of the hypothesis that living models enhance non-technical skills remains to be confirmed.

Level of evidence: Not ratable.

Two-step treatment of a giant skull vault hemangioma: A rare case report and literature review

Skull vault hemangiomas are benign vascular tumours of the calvaria that are usually asymptomatic or present as firm, painless lumps. We present a case of a 59-year-old female with a giant intraosseous calvarial hemangioma that was admitted in our department with a palpable mass over the left frontoparietal region, personality changes and impaired emotional and cognitive functions. The patient was treated with a two-step approach involving endovascular and surgical treatment, and suffered two rare, but recognized complications, a contrecoup intracerebral haemorrhage and valproate-induced stupor and parkinsonism. At the 6-month follow-up, the patient had complete recovery with a good neurological outcome.

Prognostic Value of 5-ALA Fluorescence, Tumor Cell Infiltration and Angiogenesis in the Peritumoral Brain Tissue of Brain Metastases

Simple Summary

In a recent study, we observed 5-ALA fluorescence not only in brain metastases (BM) but also in the peritumoral brain tissue. However, the histopathological correlate of visible 5-ALA fluorescence in the peritumoral brain tissue is not fully understood. Therefore, we safely collected and analyzed tissue samples from fluorescing and non-fluorescing peritumoral brain tissue. Surprisingly, 5-ALA fluorescence in the peritumoral brain tissue did not correlate with tumor cell infiltration but did show a significant relation with angiogenesis. Moreover, the presence of angiogenesis significantly correlated with shorter time to local progression/recurrence and one-year survival. Consequently, angiogenesis in the peritumoral brain tissue might be a novel prognostic marker in BM. This represents the first study in the literature describing the prognostic impact of angiogenesis in fluorescent peritumoral brain tissue of BM, which might support individualized perioperative treatment concepts in the future.

Abstract

Complete resection is an indispensable treatment option in the management of brain metastases (BM). 5-aminolevulinic acid (5-ALA) fluorescence is used for improved intraoperative visualization of tumor tissue in gliomas and was recently observed in BM. We investigated the potential of 5-ALA fluorescence to visualize the infiltrative growth of BM in the peritumoral brain tissue and its histopathological correlate. Patients with BM resection after 5-ALA administration and collection of tissue samples from peritumoral brain tissue were included. Each tissue sample was histopathologically investigated for tumor cell infiltration and angiogenesis. Altogether, 88 samples were collected from the peritumoral brain tissue in 58 BM of 55 patients. Visible 5-ALA fluorescence was found in 61 (69%) of the samples, tumor infiltration in 19 (22%) and angiogenesis in 13 (15%) of samples. Angiogenesis showed a significant correlation with presence of fluorescence (p = 0.008). Moreover, angiogenesis was related to visible 5-ALA fluorescence and showed an association with patient prognosis since it was significantly correlated to shorter time to local progression/recurrence (p = 0.001) and lower one-year survival (p = 0.031). Consequently, angiogenesis in the peritumoral brain tissue of BM might be a novel prognostic marker for individualized perioperative treatment concepts in the future.

Assessment of computed tomography perfusion software in predicting spatial location and volume of infarct in acute ischemic stroke patients: a comparison of Sphere, Vitrea, and RAPID

BACKGROUND

CT perfusion (CTP) infarct and penumbra estimations determine the eligibility of patients with acute ischemic stroke (AIS) for endovascular intervention. This study aimed to determine volumetric and spatial agreement of predicted RAPID, Vitrea, and Sphere CTP infarct with follow-up fluid attenuation inversion recovery (FLAIR) MRI infarct.

METHODS

108 consecutive patients with AIS and large vessel occlusion were included in the study between April 2019 and January 2020 . Patients were divided into two groups: endovascular intervention (n=58) and conservative treatment (n=50). Intervention patients were treated with mechanical thrombectomy and achieved successful reperfusion (Thrombolysis in Cerebral Infarction 2b/2 c/3) while patients in the conservative treatment group did not receive mechanical thrombectomy or intravenous thrombolysis. Intervention and conservative treatment patients were included to assess infarct and penumbra estimations, respectively. It was assumed that in all patients treated conservatively, penumbra converted to infarct. CTP infarct and penumbra volumes were segmented from RAPID, Vitrea, and Sphere to assess volumetric and spatial agreement with follow-up FLAIR MRI.

RESULTS

Mean infarct differences (95% CIs) between each CTP software and FLAIR MRI for each cohort were: intervention cohort: RAPID=9.0±7.7 mL, Sphere=-0.2±8.7 mL, Vitrea=-7.9±8.9 mL; conservative treatment cohort: RAPID=-31.9±21.6 mL, Sphere=-26.8±17.4 mL, Vitrea=-15.3±13.7 mL. Overlap and Dice coefficients for predicted infarct were (overlap, Dice): intervention cohort: RAPID=(0.57, 0.44), Sphere=(0.68, 0.60), Vitrea=(0.70, 0.60); conservative treatment cohort: RAPID=(0.71, 0.56), Sphere=(0.73, 0.60), Vitrea=(0.72, 0.64).

CONCLUSIONS

Sphere proved the most accurate in patients who had intervention infarct assessment as Vitrea and RAPID overestimated and underestimated infarct, respectively. Vitrea proved the most accurate in penumbra assessment for patients treated conservatively although all software overestimated penumbra.

Stent-Assisted Coil Embolization of Ruptured Blood Blister-Like Aneurysm of the Basilar Artery: A Case Report and Literature Review

Objective

Blood blister-like aneurysms (BBA) often develop on the anterior wall of the internal carotid artery, and few cases have been reported at other sites. We report a case of stent-assisted coil embolization in the acute phase for a ruptured BBA of the basilar artery.

Case Presentation

A 53-year-old woman underwent emergency stent-assisted coil embolization for subarachnoid hemorrhage due to a ruptured BBA in the main trunk of the basilar artery. Seven months after the operation, cerebral angiography confirmed no recurrence and a good clinical course.

Conclusion

Stent-assisted coil embolization for BBA may be one treatment option.

Demystifying machine learning: a primer for physicians

Machine learning is a tool for analysing digitised data sets and formulating predictions that can optimise clinical decision-making. It aims to identify complex patterns in large data sets and encode them into models that can then classify new unseen cases or make predictions on new data. Machine learning methods take several forms and individual models can be of many different types. More than 50 models have been approved for use in routine healthcare, and the numbers continue to grow exponentially. The reliability and robustness of any model depends on multiple factors, including the quality and quantity of the data used to develop the models, and the selection of features in the data considered most important to maximising accuracy. In ensuring models are safe, effective and reproducible in routine care, physicians need to have some understanding of how these models are developed and evaluated, and to collaborate with data and computer scientists in their design and validation. This narrative review introduces principles, methods and examples of machine learning in a way that does not require mastery of highly complex statistical and computational concepts.

Clinical Nomogram Predicting Intracranial Injury in Pediatric Traumatic Brain Injury

Background:

There are differences in injured mechanisms among pediatric traumatic brain injury (TBI) in developing countries. This study aimed to develop and validate clinical nomogram for predicting intracranial injury in pediatric TBI that will be implicated in balancing the unnecessary investigation in the general practice.

Materials and Methods:

The retrospective study was conducted in all patients who were younger than 15 years old and underwent computed tomography (CT) of the brain after TBI in southern Thailand. Injured mechanisms and clinical characteristics were identified and analyzed with binary logistic regression for predicting intracranial injury. Using random sampling without replacement, the total data was split into nomogram developing dataset (80%) and testing dataset (20%). Therefore, a nomogram was constructed and applied via the web-based application from the developing dataset. Using testing dataset, validation as binary classifiers was performed by various probabilities levels.

Results:

A total of 900 victims were enrolled. The mean age was 87.2 (standard deviation [SD] 57.4) months, and 65.3% of all patients injured were from road traffic accidents. The rate of positive findings in CT of the brain was 32.8%. A nomogram was developed from the significant variables, including age groups, road traffic accidents, loss of consciousness, scalp hematoma/laceration, motor weakness, signs of basilar skull fraction, low Glasgow Coma Scale score, and pupillary light reflex.

Therefore, a nomogram was developed from 80% of data and was validated from 20% of data. The accuracy, sensitivity, specificity, positive, and negative predictive values of the nomogram were 0.83, 0.42, 1.00, 1.00, and 0.81 at a cutoff value of 0.5 probability.

Conclusion:

This study provides a clinical nomogram that will be applied to making decisions in general practice as a diagnostic tool from high specificity.

Preventive Effect of Bypass Surgery on Rebleeding in Patients with Hemorrhagic Twiglike Middle Cerebral Artery

BACKGROUND

Aplastic or twiglike middle cerebral artery (Ap/T-MCA) is a rare cerebrovascular anomaly correlated to stroke. The most common characteristic of the disease is intracerebral hemorrhage. However, treatment measures that can prevent rebleeding have not yet been established.

OBJECTIVE

We sought to validate whether extracranial-intracranial (EC-IC) bypass is effective in preventing recurrent intracerebral hemorrhage in patients with Ap/T-MCA.

METHODS

Ap/T-MCA was defined on the basis of the following criteria: 1) M1 occlusion with plexiform vessels, 2) unilateral MCA involvement without progression to the contralateral side, 3) no significant stenosis in the M2 segment, and 4) no stenoocclusive lesions in other intracranial major arteries. The clinical features, surgical procedures, radiologic changes, and treatment outcomes of patients with Ap/T-MCA who presented with ipsilateral intracerebral hemorrhage at our institution from April 2004 to December 2019 were retrospectively reviewed.

RESULTS

Seven patients fulfilled the criteria for hemorrhagic Ap/T-MCA. Female preponderance was observed, and the mean age at the time of onset was 38 (range: 28-47) years. Three patients presented with pure intraventricular hemorrhage and 4 with intraparenchymal hemorrhage. Of the 4 patients, 2 had intraventricular extension. All patients underwent EC-IC bypass and did not present with stroke during the follow-up period (median: 36 [range: 5-140] months). Follow-up magnetic resonance imaging revealed regression of the twiglike vessels or periventricular choroidal anastomosis within 1 year after surgery in all patients.

CONCLUSIONS

EC-IC bypass may be a treatment option that can prevent rebleeding in patients with hemorrhagic Ap/T-MCA.

The Rise of Inflow Cisternostomy in Resource-Limited Settings: Rationale, Limitations, and Future Challenges

Low- and middle-income countries (LMICs) bear most of the global burden of traumatic brain injury (TBI), but they lack the resources to address this public health crisis. For TBI guidelines and innovations to be effective, they must consider the context in LMICs; keeping this in mind, this article will focus on the history, pathophysiology, practice, evidence, and implications of cisternostomy. In this narrative review, the author discusses the history, pathophysiology, practice, evidence, and implications of cisternostomy. Cisternostomy for the management of TBI is an innovation developed in LMICs, primarily for LMICs. Its practice is based on the cerebrospinal fluid shift edema theory that attributes injury to increased pressure within the subarachnoid space due to subarachnoid hemorrhage and subsequent dysfunction of glymphatic drainage. Early reports of the technique report significant improvements in the Glasgow Outcome Scale, lower mortality rates, and shorter intensive care unit durations. Most reports are single-center studies with small sample sizes, and the technique requires experience and skill. These limitations have led to criticisms and slow adoption of the technique. Further research is needed to establish the effect of cisternostomy on TBI outcomes.

Revision Discectomy with or without Fusion for the Treatment of Recurrent Lumbar Disc Herniation: A Nationwide Analysis of Risk Profiles and Short-Term Outcomes

OBJECTIVE

We compared the demographics, risk factors, and complications for adult patients with recurrent lumbar disc herniation (RLDH) undergoing revision discectomy with or without concurrent fusion.

METHODS

The American College of Surgeons National Surgical Quality Improvement Program database was used to identify patients who had undergone revision discectomy with or without simultaneous fusion. The demographic variables and various peri- and postoperative complications were compared between these 2 patient groups.

RESULTS

A total of 6901 discectomy patients were included in the present study, of whom 2996 (43.4%) had undergone revision discectomy with fusion and 3905 (56.6%) had undergone revision discectomy alone. The revision discectomy with fusion group was significantly more likely to be older, female, and White or Black and to have a higher average body mass index than was the revision discectomy alone group. The discectomy with fusion group had longer hospital lengths of stay and was more likely to have a diagnosis of hypertension, insulin-dependent and non-insulin-dependent diabetes, and chronic obstructive pulmonary disease. In addition, the patients who had undergone discectomy with fusion were significantly more likely to develop pneumonia, require ventilation for >48 hours, require a blood transfusion, and to develop urinary tract infection, myocardial infarction, deep vein thrombosis, or pulmonary embolism compared with the patients who had undergone revision discectomy only.

CONCLUSIONS

Our findings reveal that older patients with more comorbidities were more likely to undergo revision discectomy with fusion. Also, this surgical group experienced more adverse events after their procedure compared with the revision discectomy only group.

Machine Learning Models for Predicting Neonatal Mortality: A Systematic Review

INTRODUCTION

Approximately 7,000 newborns die every day, accounting for almost half of child deaths under 5 years of age. Deciphering which neonates are at increased risk for mortality can have an important global impact. As such, integrating high computational technology (e.g., artificial intelligence [AI]) may help identify the early and potentially modifiable predictors of neonatal mortality. Therefore, the objective of this study was to collate, critically appraise, and analyze neonatal prediction studies that included AI.

METHODS

A literature search was performed in PubMed, Cochrane, OVID, and Google Scholar. We included studies that used AI (e.g., machine learning (ML) and deep learning) to formulate prediction models for neonatal death. We excluded small studies (n < 500 individuals) and studies using only antenatal factors to predict mortality. Two independent investigators screened all articles for inclusion. The data collection consisted of study design, number of models, features used per model, feature importance, internal and/or external validation, and calibration analysis. Our primary outcome was the average area under the receiving characteristic curve (AUC) or sensitivity and specificity for all models included in each study.

RESULTS

Of 434 articles, 11 studies were included. The total number of participants was 1.26 M with gestational ages ranging from 22 weeks to term. Number of features ranged from 3 to 66 with timing of prediction as early as 5 min of life to a maximum of 7 days of age. The average number of models per study was 4, with neural network, random forest, and logistic regression comprising the most used models (58.3%). Five studies (45.5%) reported calibration plots and 2 (18.2%) conducted external validation. Eight studies reported results by AUC and 5 studies reported the sensitivity and specificity. The AUC varied from 58.3% to 97.0%. The mean sensitivities ranged from 63% to 80% and specificities from 78% to 99%. The best overall model was linear discriminant analysis, but it also had a high number of features (n = 17).

DISCUSSION/CONCLUSION

ML models can accurately predict death in neonates. This analysis demonstrates the most commonly used predictors and metrics for AI prediction models for neonatal mortality. Future studies should focus on external validation, calibration, as well as deployment of applications that can be readily accessible to health-care providers.

Current Knowledge of and Perspectives about the Pathogenesis of Blood Blister-like Aneurysms of the Internal Carotid Artery: A Review of the Literature

Blood blister-like aneurysms (BBAs) are rare and usually appear at nonbranching sites in the supraclinoid portion of the internal carotid artery (ICA). Because it is difficult to obtain histological specimens of the aneurysm wall and because experimental models are challenging to establish, the pathogenesis of BBAs remains uncertain. In this paper, we reviewed the diagnostic, radiological, and pathophysiological characteristics of patients with BBAs. We also summarized the existing evidence and potential mechanisms related to the causes of BBAs. Current evidence indicates that atherosclerosis and dissection are the main prerequisites for the formation of BBAs. Hemodynamics may play a role in the process of BBA formation due to the unique vascular anatomy of the supraclinoid ICA. Further research on histopathology and hemodynamics is warranted in this field.