Avoiding predatory publishing for early career neurosurgeons: what should you know before you submit?

BACKGROUND: Scientific research can offer the joy of discovery. For many graduating neurosurgeons, often, a seminar, class, or instructional module is their first and only formal exposure to the world of conducting research responsibly, to write down and report the results of such research. The pressure to publish scientific research is high, but any young neurosurgeon who is unaware of how predatory publishers operate can get duped by it and can lose their valuable and hard-fought research. Hence, we have attempted to provide an overview of all potentially predatory neurosurgery publications and provide some "red flags" to recognize them. METHODS: A suspected list of predatory publications was collected via a thorough review of the Neurosurgery journals listed in 4 major so-called blacklists, i.e., Beall's list, Manca's list, Cabell's blacklist, and Strinzel blacklist and then cross-referenced with UGC CARE whitelist to remove any potential legitimate journals. All journals with a scope of the Neurosurgery publication were searched using terms in the search bar: "Neurosurgery", "Neuroanatomy", "Neuropathology", and "Neurological disorder/disease". Since all predatory journals claim to be open access, all possible types of open access journals on Scimago were also searched, and thus a comparison was possible in terms of publication cost and number of legitimate open access journals when compared with predatory ones. In addition, methodologies by which these journals penetrate legitimate indexes like PubMed was investigated. RESULTS: A total of 46 predatory journals were found and were enlisted along with their publishers and web addresses. Sixty of the 360 Neurosurgery journals listed on Scimago were open access and the fee for the predatory journals was substantially lower (< $150) when compared with legitimate journals ($900-$3000). Six types of open access types exist while a total of 26 red flags in 7 stages of publication can be found in predatory journals. These journals have penetrated indexes by having similar names to legitimate journals and by publishing articles with external funding which mandate their indexing. CONCLUSION: These 46 journals were defined as predatory by 4 major blacklists, and none of them was found in the UGC Care white list. They also fulfill the 26 red-flags that define a predatory journal. The blacklist detailed here may become redundant; hence "whenever in doubt" regarding a journal with "red-flags", the authors are advised to refer to whitelists to be on the safer side. Publishing in predatory journals leads to not only loss of valuable research but also discredits a researcher among his peers and can be hindrance in career progression. Some journals are even indexed on PubMed, and they have sophisticated webpages and high-quality online presentations.

Genetic analysis of spinal dysraphism with a hamartomatous growth (appendix) of the spinal cord: a case series.

BACKGROUND: Spinal dysraphism with a hamartomatous growth (appendix) of the spinal cord is better known as herniated spinal cord. There are many arguments in favour of considering it a developmental defect. From this point of view, it is a type of neural tube disorder. Neural tube disorders can be caused by multiple factors, including a genetic factor. A common genetic defect in patients with a spinal dysraphism with a hamartomatous growth of the spinal cord is sought for. CASE PRESENTATION: In two patients with a symptomatic lesion and referred to an academic hospital a genetic analysis was performed after informed consent. Whole-exome analysis was performed. : Whole-exome analysis did not result in identification of a clinically relevant genetic variant. CONCLUSIONS: This the first study to investigate the genetic contribution to spinal dysraphism with a hamartomatous growth (appendix) of the spinal cord. We could not establish a genetic cause for this entity. This conclusion cannot be definitive due to the small sample size. However, the incidental occurrence, the lack of reports of inheritance of this disorder and the absence of contribution to syndromal disorders favours a defect of normal development of the spinal cord.

The value of the Charlson Co-morbidity Index in aneurysmal subarachnoid haemorrhage.

BACKGROUND: Several studies have included different co-morbid conditions in prediction models for stroke patients. For subarachnoid haemorrhage (SAH), it is not known whether the Charlson Co-morbidity Index (CCI) is associated with outcome. We evaluated if this index was associated with outcome in patients with ruptured intracerebral aneurysms. METHODS: The data of all consecutive aneurysmal SAH (aSAH) patients treated at the Radboudumc, Nijmegen, The Netherlands and entered in the database were retrospectively analysed. Clinical condition at admission was recorded using the WFNS (World Federation of Neurological Surgeons Grading System) grade was collected, as were the age and treatment modality. The burden of co-morbidity was retrospectively registered using the CCI. Outcome was dichotomised on the modified Rankin Scale (mRS; 0-2, favourable outcome; 3-6, unfavourable outcome). A binary logistic regression analysis was performed. RESULTS: Between 6th May 2008 and 31st July 2013, 457 patients were admitted because of non-traumatic SAH (aSAH). Seventy-seven (16.8 %) patients had no aneurysm. Of the 380 patients with aSAH, information on co-morbid conditions was available for 371 patients. Thirty-six of those 371 had no treatment because of: bad clinical condition in 34 (9.2 %), a non-treatable dissecting aneurysm in 1 (0.3 %) and the explicit wishes of another. Co-morbidity was present in 113 (31.5 %) patients. Binary logistic regression analysis revealed no added value of using the CCI in predicting the outcome (p = 0.91). CONCLUSIONS: This study reports that the CCI is not associated with the outcome classified on the mRS at 6 months in patients after aSAH. The CCI has no added value in case-mix correction.

External validation of a model to predict the survival of patients presenting with a spinal epidural metastasis.

The surgical treatment of spinal metastases is evolving. The major problem is the selection of patients who may benefit from surgical treatment. One of the criteria is an expected survival of at least 3 months. A prediction model has been previously developed. The present study has been performed in order to validate externally the model and to demonstrate that this model can be generalized to other institutions and other countries than the Netherlands. Data of 356 patients from five centers in Germany, Spain, Sweden, and the Netherlands who were treated for metastatic epidural spinal cord compression were collected. Hazard ratios in the test population corresponded with those of the developmental population. However, the observed and the expected survival were different. Analysis revealed that the baseline hazard function was significantly different. This tempted us to combine the data and develop a new prediction model. Estimating iteratively, a baseline hazard was composed. An adapted prediction model is presented. External validation of a prediction model revealed a difference in expected survival, although the relative contribution of the specific hazard ratios was the same as in the developmental population. This study emphasized the need to check the baseline hazard function in external validation. A new model has been developed using an estimated baseline hazard.

A Comparative Scientometric Analysis of the 100 Most Cited Articles of Acta Neurochirurgica (Wien) and World Neurosurgery.

BACKGROUND: Acta Neurochirurgica (ANCH) and World Neurosurgery (WN), are 2 journals of significant importance in the neurosurgical community and have been associated with international federations. These journals carry a similar impact factor. The difference is the years they have been active (ANCH starting publication in 1973 and WN in 2010). This factor allows for a unique opportunity to delve deep into comparative, scientometric parameters, to understand the evolution of neurosurgical research. METHODS: A title-specific search of the Web of Science database using the keywords "Acta Neurochirurgica," "Acta," "Neurochirurgica," "World Neurosurgery," "World," and "Neurosurgery" was performed and arranged according to number of citations. The title of the articles, authors, corresponding authors, country of origin, journal of publication, year of publication, citation count. and journal impact factor were assessed. RESULTS: The average citation for ANCH was 170.1 citations, most being original articles (83/100). The articles of WN garnered nearly 70.48 citations, averaging 8.3 citations per publication. Most corresponding authors in ANCH originated from Germany with neuro-oncology, followed by neurotrauma and vascular as subjects. In contrast, the United States followed by China were the most common countries of origin for WN, with endoscopy and skull base being the topics achieving high impact. CONCLUSIONS: Neurotrauma and consensus guidelines have been shown to have maximal citations for ANCH whereas endoscopy and skull base lesions garnered the most for WN. Author subspecialization and increased collaboration across specialties with more articles on refinement of technique and outcome have emerged as recent trends.

Factors Associated with Subsequent Subarachnoid Hemorrhages in Patients with Multiple Intracranial Aneurysms.

BACKGROUND: Detection of multiple intracranial aneurysms (MIAs) in patients with aneurysmal subarachnoid hemorrhage (aSAH) is common and the optimal management of the additional unruptured intracranial aneurysms (UIA) is often a matter of debate. We calculate the incidence and the factors associated with subsequent aSAHs from untreated additional aneurysms in a single-center group of patients with aSAH and MIAs. METHODS: Charts of patients with MIAs admitted to our neurosurgery department for aSAH between January 2000 and March 2020 were retrospectively reviewed. Incidence rate and factors associated with subsequent aSAHs were calculated with univariable and multivariable analyses. RESULTS: Of the unruptured aneurysms, 50% were preventively treated. During a median follow-up of 3 years, 20 of 174 patients (11.5%) presented with a second aSAH. Incidence of rupture of an additional untreated aneurysm was 18.05 per 1000 person/years (confidence interval, 10.69-30.47). Rupture incidence of an additional aneurysm located in the anterior circulation was 32.70 per 1000 person/years and 40.73 per 1000 person/years in the posterior circulation. Presence of untreated mirror and de novo aneurysms increased the risk of overall subsequent aSAHs by 16.9-fold and 7.6-fold, respectively. Most untreated additional aneurysms causing a subsequent aSAH were smaller than 7 mm (73.3%), with middle cerebral artery being the most frequent location (40.0%). CONCLUSIONS: Incidence of subsequent aSAHs is high in patients with aSAH-MIA. Untreated mirror and de novo aneurysms are associated with higher rupture risk. Longer follow-up and prophylactic treatment of asymptomatic aneurysms at higher rupture risk are recommended to prevent the significant poor outcome of subsequent aSAHs.

Prediction Models in Aneurysmal Subarachnoid Hemorrhage: Forecasting Clinical Outcome With Artificial Intelligence.

BACKGROUND: Predicting outcome after aneurysmal subarachnoid hemorrhage (aSAH) is known to be challenging and complex. Machine learning approaches, of which feedforward artificial neural networks (ffANNs) are the most widely used, could contribute to the patient-specific outcome prediction. OBJECTIVE: To investigate the prediction capacity of an ffANN for the patient-specific clinical outcome and the occurrence of delayed cerebral ischemia (DCI) and compare those results with the predictions of 2 internationally used scoring systems. METHODS: A prospective database was used to predict (1) death during hospitalization (ie, mortality) (n = 451), (2) unfavorable modified Rankin Scale (mRS) at 6 mo (n = 413), and (3) the occurrence of DCI (n = 362). Additionally, the predictive capacities of the ffANN were compared to those of Subarachnoid Haemorrhage International Trialists (SAHIT) and VASOGRADE to predict clinical outcome and occurrence of DCI. RESULTS: The area under the curve (AUC) of the ffANN showed to be 88%, 85%, and 72% for predicting mortality, an unfavorable mRS, and the occurrence of DCI, respectively. Sensitivity/specificity rates of the ffANN for mortality, unfavorable mRS, and the occurrence of DCI were 82%/80%, 94%/80%, and 74%/68%. The ffANN and SAHIT calculator showed similar AUCs for predicting personalized outcome. The presented ffANN and VASOGRADE were found to perform equally with regard to personalized prediction of occurrence of DCI. CONCLUSION: The presented ffANN showed equal performance when compared with VASOGRADE and SAHIT scoring systems while using less individual cases. The web interface launched simultaneously with the publication of this manuscript allows for usage of the ffANN-based prediction tool for individual data (https://nutshell-tool.com/).

Positron emission tomography for serial imaging of the contused adult rat spinal cord.

We investigated whether small-animal positron emission tomography (PET) could be used in combination with computed tomography (CT) imaging techniques for longitudinal monitoring of the injured spinal cord. In adult female Sprague-Dawley rats (n = 6), the ninth thoracic (T9) spinal cord segment was exposed by laminectomy and subsequently contused using the Infinite Horizon impactor (Precision System and Instrumentation, Lexington, KY) at 225 kDyn. In control rats (n = 4), the T9 spinal cord was exposed by laminectomy but not contused. At 0.5 hours and 3, 7, and 21 days postinjury, 2-[(18)F]fluoro-2-deoxy-d-glucose ([(18)F]FDG) was given intravenously followed 1 hour later by sequential PET and CT. Regions of interest (ROIs) at T9 (contused) and T6 (uninjured) spinal cord segments were manually defined on CT images and aided by fiduciary markers superimposed onto the coregistered PET images. Monte Carlo simulation revealed that about 33% of the activity in the ROIs was due to spillover from adjacent hot areas. A simulation-based partial-volume compensation (PVC) method was developed and used to correct for this spillover effect. With PET-CT, combined with PVC, we were able to serially measure standardized uptake values of the T9 and T6 spinal cord segments and reveal small, but significant, differences. This approach may become a tool to assess the efficacy of spinal cord repair strategies.

Variations of endonasal anatomy: relevance for the endoscopic endonasal transsphenoidal approach.

BACKGROUND: The endoscopic endonasal transsphenoidal approach (EETA) to the pituitary is performed by ear, nose, and throat (ENT) surgeons in collaboration with neurosurgeons but also by neurosurgeons alone even though neurosurgeons have not been trained in rhinological surgery. PURPOSE: To register the frequency of endonasal anatomical variations and to evaluate whether these variations hinder the progress of EETA and require extra rhinological surgical skills. METHODS: A prospective cohort study of 185 consecutive patients receiving an EETA through a binostril approach was performed. All anatomical endonasal variations were noted and the relevance for the progress of surgery evaluated. RESULTS: In 48% of patients, anatomical variations were recognized, the majority of which were spinae septi and septum deviations. In 5% of patients, the planned binostril approach had to be converted into a mononostril approach; whereas in 18% of patients with an anatomical variation, a correction had to be performed. There was no difference between the ENT surgeon and the neurosurgeon performing the approach. Complications related to the endonasal phase of the surgery occurred in 3.8%. Fluoroscopy or electromagnetic navigation has been used during 6.5% of the surgeries. CONCLUSION: Although endonasal anatomical variations are frequent, they do not pose a relevant obstacle for EETA.

Flow diversion treatment for acutely ruptured aneurysms.

BACKGROUND AND PURPOSE: Flow diverters are sometimes used in the setting of acutely ruptured aneurysms. However, thromboembolic and hemorrhagic complications are feared and evidence regarding safety is limited. Therefore, in this multicenter study we evaluated complications, clinical, and angiographic outcomes of patients treated with a flow diverter for acutely ruptured aneurysms. METHODS: We conducted a retrospective observational study of 44 consecutive patients who underwent flow diverter treatment within 15 days after rupture of an intracranial aneurysm at six centers. The primary end point was good clinical outcome, defined as modified Rankin Scale score (mRS) 0-2. Secondary endpoints were procedure-related complications and complete aneurysm occlusion at follow-up. RESULTS: At follow-up (median 3.4 months) 20 patients (45%) had a good clinical outcome. In 20 patients (45%), 25 procedure-related complications occurred. These resulted in permanent neurologic deficits in 12 patients (27%). In 5 patients (11%) aneurysm re-rupture occurred. Eight patients died resulting in an all-cause mortality rate of 18%. Procedure-related complications were associated with a poor clinical outcome (mRS 3-6; OR 5.1(95% CI 1.0 to 24.9), p=0.04). Large aneurysms were prone to re-rupture with rebleed rates of 60% (3/5) vs 5% (2/39) (p=0.01) for aneurysms with a size ≥20 mm and <20 mm, respectively. Follow-up angiography in 29 patients (median 9.7 months) showed complete aneurysm occlusion in 27 (93%). CONCLUSION: Flow diverter treatment of ruptured intracranial aneurysms was associated with high rates of procedure-related complications including aneurysm re-ruptures. Complications were associated with poor clinical outcome. In patients with available angiographic follow-up, a high occlusion rate was observed.

Regulatory T cells and the PD-L1/PD-1 pathway mediate immune suppression in malignant human brain tumors.

The brain is a specialized immune site representing a unique tumor microenvironment. The availability of fresh brain tumor material for ex vivo analysis is often limited because large parts of many brain tumors are resected using ultrasonic aspiration. We analyzed ultrasonic tumor aspirates as a biosource to study immune suppressive mechanisms in 83 human brain tumors. Lymphocyte infiltrates in brain tumor tissues and ultrasonic aspirates were comparable with respect to lymphocyte content and viability. Applying ultrasonic aspirates, we detected massive infiltration of CD4+FoxP3+CD25(high) CD127(low) regulatory T cells (Tregs) in glioblastomas (n = 29) and metastatic brain tumors (n = 20). No Treg accumulation was observed in benign tumors such as meningiomas (n = 10) and pituitary adenomas (n = 5). A significant Treg increase in blood was seen only in patients with metastatic brain tumors. Tregs in high-grade tumors exhibited an activated phenotype as indicated by decreased proliferation and elevated CTLA-4 and FoxP3 expression relative to blood Tregs. Functional analysis showed that the tumor-derived Tregs efficiently suppressed cytokine secretion and proliferation of autologous intratumoral lymphocytes. Most tumor-infiltrating Tregs were localized in close proximity to effector T cells, as visualized by immunohistochemistry. Furthermore, 61% of the malignant brain tumors expressed programmed death ligand-1 (PD-L1), while the inhibitory PD-1 receptor was expressed on CD4+ effector cells present in 26% of tumors. In conclusion, using ultrasonic tumor aspirates as a biosource we identified Tregs and the PD-L1/PD-1 pathway as immune suppressive mechanisms in malignant but not benign human brain tumors.

NeuroForm Atlas Stent-Assisted Coiling: Preliminary Results.

BACKGROUND: Stent-assisted coiling (SAC) is increasingly being performed as intervention for wide-neck intracranial aneurysms. The NeuroForm Atlas Stent (CE-marked; Stryker, Kalamazoo, Michigan) is relatively new. OBJECTIVE: To evaluate the effectiveness and safety of NeuroForm Atlas SAC for intracranial aneurysms in the first such study. METHODS: We retrospectively analyzed data from all patients treated with the NeuroForm Atlas SAC of an intracranial aneurysm, both ruptured and unruptured, between June 2015 and December 2016. Primary end-points were favorable clinical outcomes (modified Rankin scale score 0-2) and successful aneurysm occlusion (Raymond-Roy class I/II), both at 6-mo follow-up. Secondary end-points were the occurrence of intervention-related complications leading to permanent neurological deficit, the occurrence of intervention-related stroke and neurological death, immediate aneurysm occlusion, rupture (or rerupture) of the aneurysm, and recanalization. RESULTS: Twenty-seven consecutive patients, 10 with ruptured saccular wide-neck aneurysms, were treated with NeuroForm Atlas SAC. At 6-mo follow-up, 18/26 (69.2%) survivors had successful aneurysm occlusion and 22/26 (84.6%) had favorable clinical outcome. One patient had died of a cause unrelated to treatment. No intervention-related complications leading to permanent neurological deficit occurred. However, intraprocedural thromboembolic complications occurred in 4/27 patients (14.8%), and ischemic stroke related to treatment occurred in 4/26 (15.4%). No hemorrhagic complications were observed. CONCLUSION: NeuroForm Atlas SAC is a feasible way to treat ruptured and unruptured wide-neck aneurysms that are not amenable to conventional coiling or clipping. Aneurysm occlusion and favorable clinical outcome are consistent with previously reported rates for SAC of wide-neck aneurysms with other devices.

Pathogenesis of Idiopathic Ventral Herniation of Spinal Cord: Neuropathologic Analysis.

BACKGROUND: Idiopathic ventral herniation of the spinal cord is rarely seen as a cause of gradually increasing neurologic deficit. Its cause has never been clarified. It could be the result of a developmental disorder at 30- to 60-day gestational age. Neuropathologic analysis of herniated spinal cord tissue could probably support this hypothesis. CASE DESCRIPTION: In a patient suffering from idiopathic ventral herniation of the spinal cord, a biopsy was performed in order to reduce the space-occupying effect. The biopsy was taken while intraoperative neuromonitoring was used. The patient recovered uneventfully without any additional deficit. Tissue analysis included histopathologic, immunohistochemical, and molecular examination (methylation profiling). The tissue did not appear as a normally functioning spinal cord; instead, a non-neoplastic glio-(neuronal) proliferation was found. CONCLUSION: These findings support a developmental disorder as a cause for idiopathic ventral spinal cord herniation.

Toward Shorter Hospitalization After Endoscopic Transsphenoidal Pituitary Surgery: Day-by-Day Analysis of Early Postoperative Complications and Interventions.

BACKGROUND: It is unclear which patients have the greatest risk of developing complications in the first days after endoscopic transsphenoidal pituitary surgery (ETS) and how long patients should stay hospitalized after surgery. The objective of this study is to identify which patients are at risk for early postoperative medical and surgical reinterventions to optimize the length of hospitalization. METHODS: The medical records of 146 patients who underwent ETS for a pituitary adenoma between January 2013 and July 2016 were reviewed retrospectively. Data were collected on baseline patient-related characteristics, characteristics of the pituitary adenoma, perioperative complications and interventions, and postoperative outcomes. Patients who underwent additional interventions on days 2, 3, and 4 after ETS were identified as cases, and patients who did not have any interventions after day 1 postoperatively were identified as controls. RESULTS: Diabetes mellitus (odds ratio [OR], 4.279; 95% confidence interval [CI], 1.149-15.933; P = 0.03), incomplete adenoma resection (OR, 2.840; 95% CI, 1.228-6.568; P = 0.02) and increased morning sodium concentration on day 2 after surgery (OR, 5.211; 95% CI, 2.158-12.579; P <0.001) were associated with reinterventions. Patients without interventions on day 1 or 2 had only an 18.6% chance of a reintervention (OR, 0.201; 95% CI, 0.095-0.424). CONCLUSIONS: Patients with diabetes mellitus, incomplete adenoma resection, and increased morning sodium concentration on day 2 after surgery have an increased chance on reinterventions. In addition, patients without any interventions on day 1 and 2 are at low risk for later reinterventions. These patients could be suitable candidates for early hospital discharge.

Safety and efficacy of a novel polyethylene glycol hydrogel sealant for watertight dural repair.

OBJECT: The authors prospectively evaluated the safety and efficacy of a novel polyethylene glycol (PEG) hydrogel sealant in patients undergoing elective cranial surgery with documented cerebrospinal fluid (CSF) leakage after sutured dural repair. METHODS: The PEG hydrogel sealant was used at 11 different study sites in 111 patients with documented intraoperative CSF leakage after neurosurgical dural repair for a variety of conditions. Intraoperative CSF leakage was either spontaneous or induced by a Valsalva maneuver. Patients were monitored for 3 months postoperatively with physical examinations, clinical laboratory analyses, and diagnostic imaging. The PEG hydrogel sealant was 100% effective in stopping CSF leakage in all patients. There were no sealant-related adverse events and all clinical outcomes were consistent with expectations for seriously ill patients undergoing prolonged neurosurgical procedures. CONCLUSIONS: The PEG hydrogel sealant provides a safe and effective watertight closure when used as an adjunct to sutured dural repair during cranial surgery.

Design of Lamifuse: a randomised, multi-centre controlled trial comparing laminectomy without or with dorsal fusion for cervical myeloradiculopathy.

BACKGROUND: laminectomy is a valuable surgical treatment for some patients with a cervical radiculomyelopathy due to cervical spinal stenosis. More recently attention has been given to motion of the spinal cord over spondylotic spurs as a cause of myelopathic changes. Immobilisation by fusion could have a positive effect on the recovery of myelopathic signs or changes. This has never been investigated in a prospective, randomised trial. Lamifuse is an acronyme for laminectomy and fusion. METHODS/DESIGN: Lamifuse is a multicentre, randomised controlled trial comparing laminectomy with and without fusion in patients with a symptomatic cervical canal stenosis. The study population will be enrolled from patients that are 60 years or older with myelopathic signs and/or symptoms due to a cervical canal stenosis. A kyphotis shape of the cervical spine is an exclusion criterium. Each treatment arm needs 30 patients. DISCUSSION: This study will contribute to the discussion whether additional fusion after a cervical laminectomy results in a better clinical outcome. ISRCT NUMBER: ISRCTN72800446.

The Pathogenesis of Ventral Idiopathic Herniation of the Spinal Cord: A Hypothesis Based on the Review of the Literature.

Idiopathic ventral herniation of the spinal cord (SC) is not often encountered in daily practice. Its clinical prevalence, however, will increase through increasing awareness and more frequent use of MRI. A clear explanation of its pathophysiology has never been formulated. It was hypothesized that the findings during surgery might indicate the real causative mechanism. An extensive literature search was performed, using Embase, PubMed, and Google Scholar. Titles and abstracts were screened by two investigators, using strict inclusion and exclusion criteria. Reference lists of the full paper versions of each included article were checked. The following data were registered for the articles included: age, gender, level of herniation, relation to intervertebral disk, duration of symptoms, findings from surgery, and outcomes. Nine cases treated at our department were added. A total of 117 articles reporting on 259 patients were included. Including our cases, 268 patients were reviewed. Females outnumbered males (160/100). The mean age was 51.3 ± 12.0 years. In 236 patients, the duration of symptoms was reported: 55.5 ± 55.6 months. In 178 patients, the intraoperative findings for the herniated part of the SC were not mentioned. In 59 patients, a tumor-like extrusion was seen, without any alteration to the SC. Deformation of the SC itself was never observed. Biopsies of these structures were without clinical consequence. Based on the intraoperative findings reported in literature and the cases presented, acquired causes, such as trauma and erosion of the dura due to a herniated disk, were not plausible. We hypothesize that a non-functioning appendix to the SC can only develop during an early embryologic phase, in which several layers separate. We propose renaming this entity as congenital transdural appendix of the SC.

Bone marrow stromal cells for repair of the spinal cord: towards clinical application.

Stem cells have been recognized and intensively studied for their potential use in restorative approaches for degenerative diseases and traumatic injuries. In the central nervous system (CNS), stem cell-based strategies have been proposed to replace lost neurons in degenerative diseases such as Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis (Lou Gehrig's disease), or to replace lost oligodendrocytes in demyelinating diseases such as multiple sclerosis. Stem cells have also been implicated in repair of the adult spinal cord. An impact to the spinal cord results in immediate damage to tissue including blood vessels, causing loss of neurons, astrocytes, and oligodendrocytes. In time, more tissue nearby or away from the injury site is lost due to secondary injury. In case of relatively minor damage to the cord some return of function can be observed, but in most cases the neurological loss is permanent. This review will focus on in vitro and in vivo studies on the use of bone marrow stromal cells (BMSCs), a heterogeneous cell population that includes mesenchymal stem cells, for repair of the spinal cord in experimental injury models and their potential for human application. To optimally benefit from BMSCs for repair of the spinal cord it is imperative to develop in vitro techniques that will generate the desired cell type and/or a large enough number for in vivo transplantation approaches. We will also assess the potential and possible pitfalls for use of BMSCs in humans and ongoing clinical trials.