A Single-Centre Experience of the Management and Surgical Outcomes of Late-Onset Idiopathic Aqueductal Stenosis.

Background Although idiopathic aqueductal stenosis is a congenital disorder, some patients present in adulthood. Many theories have tried to account for the late-onset presentation; however, the aetiology remains uncertain. This study aimed to investigate the clinical presentation, management, and outcomes of patients with late-onset idiopathic aqueductal stenosis (LIAS) managed at our centre. Methodology A retrospective study of patients with a diagnosis of LIAS managed at our centre between 1996 and 2018 was undertaken. Data on clinical presentation, imaging, management, and outcomes were retrieved from patient records and radiology reports. Results A total of 20 patients were diagnosed with LIAS during the study period. Endoscopic third ventriculostomy (ETV) was the initial modality of treatment for nine patients, ventriculoperitoneal shunt (VPS) for four patients, and conservative management in seven patients, in four of them intracranial pressure (ICP) was found to be normal following a period of ICP monitoring. The median follow-up period was three years (1 month to 24 years). One patient was lost to follow-up. One ETV failed in the first six months necessitating VPS insertion. Two cases that were initially managed conservatively required a VPS three and nine years following the initial presentation. Of the patients undergoing VPS insertion, all subsequently required valve adjustment or surgical revision. Conclusions The majority of patients with LIAS undergoing ETV were managed successfully, whereas VPS insertion was associated with a high rate of revision surgery in this cohort. ETV should be considered as the treatment of choice to avoid the long-term complications of shunting for patients with LIAS.

Dundee Annual Neurosurgery Skills Event (DANSE)-Improving the Availability and Affordability of Neurosurgical Skills Workshops for Medical Students.

Background Neurosurgery can be a daunting career choice for medical students, with preparation for trainee application often being inaccessible and expensive. This article describes a student-led neurosurgical skills event supported by local neurosurgery faculty members. Such event was designed to offer a means to bridge this gap by providing an opportunity to practice neurosurgical techniques in simulation, and learn about what a career in neurosurgery involves. Methods Pre- and postskills laboratory surveys were used to ascertain the baseline confidence and knowledge of common neurosurgical techniques, as well as to what both the application to neurosurgery and the typical workload of a neurosurgeon involves. The conference offered six neurosurgical workshops as well as three lectures to provide practical and theoretical learning opportunities. The session included introduction to the candidates and faculty, identification of learning objectives, and career discussion. Postcourse feedback also was also used to assess learning outcomes. Results Eighteen students attended the event. Postskills event, students were significantly more likely to understand the principles behind all of the relevant neurosurgical skills included on the day. Additionally, students were more likely to understand what a career in neurosurgery involves, and how to approach applying for a training number. Respondents enjoyed the workshops, valued hands-on experience and interactions with consultants, found it affordable, and would recommend to their peers. Conclusions For medical students interested in a career in neurosurgery, opportunities to learn relevant techniques and skills are often expensive and difficult to come across. Here, we highlight affordable methods of simulation to result in significant student satisfaction. Additionally, providing ample opportunity to practice different neurosurgical techniques under almost 1:1 level tutoring enables significant increases in students' confidence and understanding of different neurosurgical concepts. We greatly encourage other medical student groups to develop their own hands-on simulation events to attract medical students to a surgical field often considered daunting and inaccessible, and address gaps in the medical school curriculum.

Repair of lateral temporo-sphenoidal encephalocoele via an endoscopic transorbital approach: ex vivo 3D printed simulation followed by in vivo deployment.

BACKGROUND: A temporo-sphenoidal encephalocoele occurs when temporal lobe herniates through a defect in the greater wing of the sphenoid bone into the sphenoid air sinus. The natural history is not well-understood, though presentation in adulthood with CSF rhinorrhoea and/or meningitis is typical. Lateral pneumatisation of the sphenoid sinus and elevated BMI may be contributory. AIMS: We explored the feasibility of a transorbital approach (TOA) for repair, using a combination of 3D modelling and simulation. We then successfully deployed this technique in vivo. METHODS: CT imaging for three patients who had previously undergone transcranial repair of lateral temporo-sphenoidal encephalocoele was used to generate data allowing 3D printed models of the skull base to be produced. The transorbital approach was simulated by performing a lateral orbitotomy followed by drilling of the sphenoid wing to expose the antero-basal middle fossa. 3D object scanning was used to create virtual models of the skull base post-surgery, from which surgical access was quantified in two ways: the area (mm2) of the middle fossa exposed by the TOA and the vertical attack angle. RESULTS: The mean surface area of the cranial access window achieved by simulated TOA was 325mm2. The mean vertical attack angle was 25°. One patient was subsequently treated successfully via TOA with no recurrence of their CSF leak, no orbital morbidity, excellent cosmesis, but resolving V2 numbness (follow-up 7 months). CONCLUSIONS: We have shown that the transorbital approach provides adequate surgical access. In our single case, surgical repair of a lateral temporo-sphenoidal encephalocoele via TOA was feasible, safe, and effective. This approach may offer some advantages compared with transcranial or endonasal approaches.

COVID-19 and Spontaneous Resolution of Lumbar Disk Prolapse: A Retrospective Cohort Study of Patients Awaiting Microdiscectomy.

BACKGROUND: Between individual patients with lumbar disk prolapse (LDP), the natural course of disease is significantly variable. Spontaneous resolution is reported to occur in up to 70% of cases. However, we currently cannot predict for whom and when this will occur. Neurosurgical intervention is indicated for LDP patients with nontolerable pain after at least 8 to 12 weeks of conservative management, or significant neurologic deficit. Channeling essential resources in the National Health Service (NHS) to fight the COVID-19 pandemic led to the postponement of most elective operations, including microdiskectomy. This left many LDP patients previously considered to be surgical candidates with conservative-only options in the interim. To our knowledge, we are the first center to report the specific impact of the peri- and postpandemic period on waiting list times, delayed elective microdiskectomy, and the incidence of spontaneous LDP resolution. METHODS: Retrospective case series of a prospectively collected electronic departmental database identified LDP patients who would have been impacted by the COVID-19 pandemic at some point in their care pathway (March 2020-February 2022). Further information was obtained from electronic patient records. RESULTS: In total, 139 LDP patients were listed for elective microdiskectomy at the time of postponement of elective surgery. Over a third of LDP patients (n = 47, 33.8%), in shared decision with the responsible neurosurgeon, had their rescheduled microdiskectomy canceled due to clinical improvement (14.1%), radiologic regression (6.5%), or both (12.2%). CONCLUSION: Our single-center retrospective analysis revealed that for over a third of LDP patients, the prolonged postpandemic waiting list times for elective microdiskectomy resulted in their surgery not taking place either due to spontaneous clinical improvement or proven radiologic regression. Considering this, a prolonged conservative approach to LDP may be appropriate in some patients, allowing time for natural resolution, while avoiding perioperative risks.

Continuous pH monitoring using a sensor for the early detection of anastomotic leaks.

Anastomotic leaks (AL) and staple line leaks are a serious post-operative complication that can develop following bariatric surgery. The delay in the onset of symptoms following a leak usually results in reactive diagnostics and treatment, leading to increased patient morbidity and mortality, and a clinical and economic burden on both the patient and the hospital. Despite support in literature for pH as a biomarker for early detection of AL, the current methods of pH detection require significant clinician involvement and resources. Presented here is a polyaniline (PANI)-based pH sensor that can be connected inline to surgical drains to continuously monitor peritoneal secretion in real time for homeostatic changes in pH. During this study, the baseline peritoneal fluid pH was measured in two pigs using the PANI sensor and verified using a benchtop pH probe. The PANI sensor was then utilized to continuously monitor the changes in the pH of peritoneal effluent, as a gastric leak was simulated. The inline sensors were able to detect the resulting local changes in drainage pH within 10 min of leak induction. The successful implementation of this sensor in clinical practice can both enable high efficiency continuous monitoring of patient status and drastically decrease the time required to detect AL, thus potentially decreasing the clinical and economic burden incurred by gastric leaks.

Fat in the Fossa and the Sphenoid Sinus: A Simple and Effective Solution to CSF Leaks in Transsphenoidal Surgery. Cohort Study and Systematic Review.

Objectives Cerebrospinal fluid (CSF) leak following endoscopic transsphenoidal surgery (TSS) remains a challenge and is associated with high morbidity. We perform a primary repair with f at in the pituitary f ossa and further fat in the s phenoid sinus (FFS). We compare the efficacy of this FFS technique with other repair methods and perform a systematic review. Design, Patients, and Methods This is a retrospective analysis of patients undergoing standard TSS from 2009 to 2020, comparing the incidence of significant postoperative CSF rhinorrhea (requiring intervention) using the FFS technique compared with other intraoperative repair strategies. Systematic review of current repair methods described in the literature was performed following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines. Results In all, there were 439 patients, with 276 patients undergoing multilayer repair, 68 patients FFS repair, and 95 patients no repair. No significant differences were observed in baseline demographics between the groups. Postoperative CSF leak requiring intervention was significantly lower in the FFS repair group (4.4%) compared with the multilayer (20.3%) and no repair groups (12.6%, p < 0.01). This translated to fewer reoperations (2.9% FFS vs. 13.4% multilayer vs. 8.4% no repair, p < 0.05), fewer lumbar drains (2.9% FFS vs. 15.6% multilayer vs. 5.3% no repair, p < 0.01), and shorter hospital stay (median days: 4 [3-7] FFS vs. 6 (5-10) multilayer vs. 5 (3-7) no repair, p < 0.01). Risk factors for postoperative leak included female gender, perioperative lumbar drain, and intraoperative leak. Conclusion Autologous fat on fat graft for standard endoscopic transsphenoidal approach effectively reduces the risk of significant postoperative CSF leak with reduced reoperation and shorter hospital stay.

Non-penetrating deep sclerectomy versus combined trabeculotomy-trabeculectomy in primary congenital glaucoma.

Background: The primary mode of therapy in children with primary congenital glaucoma (PCG) and mild or no corneal edema is goniotomy, which has a high success rate. However, in developing countries, the diagnosis of PCG is usually delayed, and corneal cloudiness interferes with goniotomy. Therefore, trabeculotomy may be the best choice in such eyes. We compared the short-term efficacy and safety of primary combined trabeculotomy-trabeculectomy (primary CTT) with that of non-penetrating deep sclerectomy (NPDS) in managing PCG. Methods: This prospective, randomized, comparative study included patients with PCG referred to Al-Azhar University Hospitals within a 1-year period. Eyes were randomly allocated to one of two groups: eyes in NPDS group underwent NPDS, and those in primary CTT group underwent primary CTT. Baseline and frequent postoperative assessments of intraocular pressure (IOP), cup-to-disc ratio (C/D ratio), corneal diameter, and axial length were performed for up to 6 months. The success rates were recorded in both groups. Results: Forty eyes of 26 patients were included, with 20 eyes allocated to each group. The mean (standard deviation) age of all patients was 12.9 (9.5) months, with comparable ages and sex ratios between groups (both P > 0.05). Both groups demonstrated a significant reduction in IOP and C/D ratio at each postoperative visit compared to the baseline visit (all P < 0.001), with no significant difference detected between the groups (all P > 0.05), except for a significantly lower IOP in NPDS group at 1 month (P < 0.05). The corneal diameter and axial length were comparable between groups at baseline and remained unchanged at all postoperative visits (all P > 0.05). The groups had comparable success rates (P > 0.05). No serious complications were detected. Conclusions: CTT and NPDS both yielded reasonable IOP control and reversal of cupping in eyes with PCG. We observed equal effectiveness of the surgical procedures without major safety concerns. Further large-scale clinical trials with longer follow-up periods are needed to verify our preliminary findings.

Fully Endoscopic Microvascular Decompression for Trigeminal Neuralgia: Technical Note Describing a Single-Center Experience.

BACKGROUND: Microscopic microvascular decompression (MVD) of the trigeminal nerve is the gold standard surgical treatment for medically refractory classical trigeminal neuralgia. Endoscopy has significantly advanced surgery and provides enhanced visualization of the cerebellopontine angle and its critical neurovascular structures. We present our initial experience of fully endoscopic microvascular decompression (e-MVD). METHODS: This retrospective case series investigated e-MVD performed from September 2016 to February 2020 at a single institution. Clinical data including presenting symptoms, medications, operative findings, postoperative complications, and outcomes were recorded. The 5-point Barrow Neurological Institute (BNI) pain intensity score was used to quantify patients' pain relief. RESULTS: During the study period, 25 patients with trigeminal neuralgia (10 males, 15 females; mean [SD] age = 63 [10.4] years) underwent e-MVD. All patients had a preoperative BNI score of V. The left side was affected in 15 patients. Complications occurred in 2 patients: both experienced hearing loss, and one experienced transient facial weakness 7 days after surgery. The facial weakness had resolved by the last follow-up. All patients were completely pain-free (BNI score I) immediately postoperatively. On latest follow-up, 22 patients have remained pain-free, and 3 patients have recurrent pain that is being controlled with medication (BNI score III). CONCLUSIONS: Our study demonstrated that e-MVD is a safe, possibly effective method of performing MVD with the added benefit of improved visualization of the operative field for the operating surgeon and the surgical team. Larger prospective studies are required to evaluate whether performing e-MVD confers any additional benefits in long-term clinical outcome of patients with trigeminal neuralgia.

Systematic Review Comparing Open versus Endoscopic Surgery in Clival Chordomas and a 10-Year Single-Center Experience.

Objectives Chordomas are rare, slow-growing, and osteo-destructive tumors of the primitive notochord. There is still contention in the literature as to the optimal management of chordoma. We conducted a systematic review of the surgical management of chordoma along with our 10-year institutional experience. Design A systematic search of the literature was performed in October 2020 by using MEDLINE and EMBASE for articles relating to the surgical management of clival chordomas. We also searched for all adult patients surgically treated for primary clival chordomas at our institute between 2009 and 2019. Participants Only articles describing chordomas arising from the clivus were included in the analysis. For our institution experience, only adult primary clival chordoma cases were included. Main Outcome Measures Patients were divided into endoscopic or open surgery. Rate of gross total resection (GTR), recurrence, and complications were measured. Results Our literature search yielded 24 articles to include in the study. Mean GTR rate among endoscopic cases was 51.9% versus 41.7% for open surgery. Among the eight cases in our institutional experience, we found similar GTR rates between endoscopic and open surgery. Conclusion Although there is clear evidence in the literature that endoscopic approaches provide better rates of GTR with fewer overall complications compared to open surgery. However, there are still situations where endoscopy is not viable, and thus, open surgery should still be considered if required.

Evidence-based surveillance protocol for vestibular schwannomas: a long-term analysis of tumor growth using conditional probability.

OBJECTIVE: The growth characteristics of vestibular schwannomas (VSs) under surveillance can be studied using a Bayesian method of growth risk stratification by time after surveillance onset, allowing dynamic evaluations of growth risks. There is no consensus on the optimum surveillance strategy in terms of frequency and duration, particularly for long-term growth risks. In this study, the long-term conditional probability of new VS growth was reported for patients after 5 years of demonstrated nongrowth. This allowed modeling of long-term VS growth risks, the creation of an evidence-based surveillance protocol, and the proposal of a cost-benefit analysis decision aid. METHODS: The authors performed an international multicenter retrospective analysis of prospectively collected databases from five tertiary care referral skull base units. Patients diagnosed with sporadic unilateral VS between 1990 and 2010 who had a minimum of 10 years of surveillance MRI showing VS nongrowth in the first 5 years of follow-up were included in the analysis. Conditional probabilities of growth were calculated according to Bayes' theorem, and nonlinear regression analyses allowed modeling of growth. A cost-benefit analysis was also performed. RESULTS: A total of 354 patients were included in the study. Across the surveillance period from 6 to 10 years postdiagnosis, a total of 12 tumors were seen to grow (3.4%). There was no significant difference in long-term growth risk for intracanalicular versus extracanalicular VSs (p = 0.41). At 6 years, the residual conditional probability of growth from this point onward was seen to be 2.28% (95% CI 0.70%-5.44%); at 7 years, 1.35% (95% CI 0.25%-4.10%); at 8 years, 0.80% (95% CI 0.07%-3.25%); at 9 years, 0.47% (95% CI 0.01%-2.71%); and at 10 years, 0.28% (95% CI 0.00%-2.37%). Modeling determined that the remaining lifetime risk of growth would be less than 1% at 7 years 7 months, less than 0.5% at 8 years 11 months, and less than 0.25% at 10 years 4 months. CONCLUSIONS: This multicenter study evaluates the conditional probability of VS growth in patients with long-term VS surveillance (6-10 years). On the basis of these growth risks, the authors posited a surveillance protocol with imaging at 6 months (t = 0.5), annually for 3 years (t = 1.5, 2.5, 3.5), twice at 2-year intervals (t = 5.5, 7.5), and a final scan after 3 years (t = 10.5). This can be used to better inform patients of their risk of growth at particular points along their surveillance timeline, balancing the risk of missing late growth with the costs of repeated imaging. A cost-benefit analysis decision aid was also proposed to allow units to make their own decisions regarding the cessation of surveillance.

Automated Koos Classification of Vestibular Schwannoma.

Objective: The Koos grading scale is a frequently used classification system for vestibular schwannoma (VS) that accounts for extrameatal tumor dimension and compression of the brain stem. We propose an artificial intelligence (AI) pipeline to fully automate the segmentation and Koos classification of VS from MRI to improve clinical workflow and facilitate patient management. Methods: We propose a method for Koos classification that does not only rely on available images but also on automatically generated segmentations. Artificial neural networks were trained and tested based on manual tumor segmentations and ground truth Koos grades of contrast-enhanced T1-weighted (ceT1) and high-resolution T2-weighted (hrT2) MR images from subjects with a single sporadic VS, acquired on a single scanner and with a standardized protocol. The first stage of the pipeline comprises a convolutional neural network (CNN) which can segment the VS and 7 adjacent structures. For the second stage, we propose two complementary approaches that are combined in an ensemble. The first approach applies a second CNN to the segmentation output to predict the Koos grade, the other approach extracts handcrafted features which are passed to a Random Forest classifier. The pipeline results were compared to those achieved by two neurosurgeons. Results: Eligible patients (n = 308) were pseudo-randomly split into 5 groups to evaluate the model performance with 5-fold cross-validation. The weighted macro-averaged mean absolute error (MA-MAE), weighted macro-averaged F1 score (F1), and accuracy score of the ensemble model were assessed on the testing sets as follows: MA-MAE = 0.11 ± 0.05, F1 = 89.3 ± 3.0%, accuracy = 89.3 ± 2.9%, which was comparable to the average performance of two neurosurgeons: MA-MAE = 0.11 ± 0.08, F1 = 89.1 ± 5.2, accuracy = 88.6 ± 5.8%. Inter-rater reliability was assessed by calculating Fleiss' generalized kappa (k = 0.68) based on all 308 cases, and intra-rater reliabilities of annotator 1 (k = 0.95) and annotator 2 (k = 0.82) were calculated according to the weighted kappa metric with quadratic (Fleiss-Cohen) weights based on 15 randomly selected cases. Conclusions: We developed the first AI framework to automatically classify VS according to the Koos scale. The excellent results show that the accuracy of the framework is comparable to that of neurosurgeons and may therefore facilitate management of patients with VS. The models, code, and ground truth Koos grades for a subset of publicly available images (n = 188) will be released upon publication.

Surgical Management of Spinal Chordoma: A Systematic Review and Single-Center Experience.

OBJECTIVE: Chordoma is a rare neoplasm of the neuraxis derived from remnants of the primitive notochord. The importance of wide margins and use of adjuvant therapy in spinal chordomas are still contentious points in the management of spinal chordomas. We conducted a systematic review of the surgical management of spinal chordomas alongside our 10-year institutional experience. METHODS: A systematic search of the literature was performed in November 2020 using Embase and MEDLINE for articles regarding the surgical management of chordomas arising from the mobile spine and sacrum. We also searched for all adult patients who were surgically managed for spinal chordomas at our institute between 2010 and 2020. In both the systematic review and our institutional case series, data on adequacy of resection, use of adjuvant therapy, complications, recurrence (local or metastatic), and survival outcomes were collected. RESULTS: We identified and analyzed 42 articles, yielding 1531 patients, from which the overall gross total or wide resection rate was 54.9%. Among the 8 cases in our institutional experience (4 sacral, 3 cervical, and 1 lumbar), we achieved gross total resection in 50% of initial operations. The recurrence rate was 25% in our gross total resection group and 50% where initial resection was subtotal. Of patients, 75% had no evidence of recurrence at most recent follow-up. CONCLUSIONS: Albeit difficult at times because of the proximity to neurovascular tissue, achieving a wide resection followed by adjuvant therapy for spinal chordomas is of great importance. Multidisciplinary discussion is valuable to ensure the best outcome for the patient.

Utility of image-guided external ventriculostomy: analysis of contemporary practice in the United Kingdom and Ireland.

OBJECTIVE: Freehand external ventricular drain (EVD) insertion is associated with a high rate of catheter misplacement. Image-guided EVD placement with neuronavigation or ultrasound has been proposed as a safer, more accurate alternative with potential to facilitate proper placement and reduce catheter malfunction risk. This study aimed to determine the impact of image-guided EVD placement on catheter tip position and drain functionality. METHODS: This study is a secondary analysis of a data set from a prospective, multicenter study. Data were collated for EVD placements undertaken in the United Kingdom and Ireland from November 2014 to April 2015. In total, 21 large tertiary care academic medical centers were included. RESULTS: Over the study period, 632 EVDs were inserted and 65.9% had tips lying free-floating in the CSF. Only 19.6% of insertions took place under image guidance. The use of image guidance did not significantly improve the position of the catheter tip on postoperative imaging, even when stratified by ventricular size. There was also no association between navigation use and drain blockage. CONCLUSIONS: Image-guided EVD placement was not associated with an increased likelihood of achieving optimal catheter position or with a lower rate of catheter blockage. Educational efforts should aim to enhance surgeons' ability to apply the technique correctly in cases of disturbed cerebral anatomy or small ventricles to reduce procedural risks and facilitate effective catheter positioning.

Transcortical Approach to Deep-Seated Intraventricular and Intra-axial Tumors Using a Tubular Retractor System: A Technical Note and Review of the Literature.

BACKGROUND: Retraction of white matter overlying a brain lesion can be difficult without causing significant trauma especially when using traditional methods of bladed retractors. These conventional retractors can produce regions of focal pressure resulting in contusions and areas of infarct. METHODS: In this article, we present a retrospective case series of six patients with deep-seated intraventricular and intra-axial tumors that were approached using a ViewSite Brain Access System (tubular retractor). The authors describe a unique method of creating a pathway using a dilated glove. We shall also review the relevant literature that reports this type of surgery. Cases included three cases with third ventricular colloid cysts, one case of a third ventricular arachnoid cyst, one case with a lateral ventricular neurocytoma, and a case with a deeply seated intra-axial metastatic tumor. RESULTS: Gross total resection was achieved in five cases with small residual in the central neurocytoma operation, with no documented neurological deficit in any case. One case had persistent memory problems and one case had continuing decline from the metastatic disease. CONCLUSION: The introduction of tubular-shaped retractor systems has offered the advantage of reducing retraction pressures and distributing any remaining force in a more even and larger distributed area, thus reducing the risk of previous associated morbidity while also permitting great visualization of the target lesion.

Shunt disconnection is less likely using a surgeon's knot compared with a surgical constrictor knot.

INTRODUCTION: Ventriculo-peritoneal shunt malfunction is a common neurosurgical presentation, which may occur as a result of shunt disconnection at the level of the valve. Previous studies assessing ligatures have suggested that the constrictor knot is stronger in securing a ligature compared to the surgeon's knot. Our study compared the ability of each knot to secure shunt tubing to the valve. METHODS: A medtronic shunt valve was secured to a peritoneal catheter using the surgeon's knot versus constrictor's knot. The weight and subsequent force (N) required to pull off the shunt tubing at the knot site were recorded. RESULTS: The mean pull-off force was 11.7 N for the surgeon knot, and 8.9 N for the constrictor knot. There was significant difference in favour for the surgeon's knot compared to the constrictor knot. CONCLUSIONS: The surgeon's knot is significantly stronger than the constrictor knot for securing a peritoneal catheter to a CSF shunt valve.

Diffuse Traumatic Subarachnoid Hemorrhage Mimicking Aneurysmal Bleeding Secondary to Ophthalmic Artery Avulsion: Case Report and Review of the Literature.

BACKGROUND: Traumatic subarachnoid hemorrhage (SAH) is a common finding following traumatic brain injury. In some cases, it can be associated with hydrocephalus. This type of hemorrhage is mostly caused by the rupture of small vessels in the brain and is usually managed conservatively. CASE DESCRIPTION: We present a case of a 60-year-old woman who presented with traumatic luxation of the eye following a fall. This resulted in diffuse SAH (Fisher grade IV) with associated hydrocephalus. We also report on 3 previous similar cases found in the literature. Avulsion of the ophthalmic artery was found to be the cause of the traumatic SAH. Apart from cerebrospinal fluid diversion using an external ventricular drain, the case was managed conservatively. There was no evidence of delayed clinical or radiologic vasospasm. CONCLUSIONS: Traumatic avulsion of the ophthalmic artery may result in diffuse SAH, mimicking that of aneurysmal rupture. This case shows that management of early complications, such as hydrocephalus and seizures, should be the main aim. Surgical or endovascular treatment of the injured artery, however, would be unnecessary.

Estimating the Frequency of Horizontal Gene Transfer Using Phylogenetic Models of Gene Gain and Loss.

We analyze patterns of gene presence and absence in a maximum likelihood framework with rate parameters for gene gain and loss. Standard methods allow independent gains and losses in different parts of a tree. While losses of the same gene are likely to be frequent, multiple gains need to be considered carefully. A gene gain could occur by horizontal transfer or by origin of a gene within the lineage being studied. If a gene is gained more than once, then at least one of these gains must be a horizontal transfer. A key parameter is the ratio of gain to loss rates, a/v We consider the limiting case known as the infinitely many genes model, where a/v tends to zero and a gene cannot be gained more than once. The infinitely many genes model is used as a null model in comparison to models that allow multiple gains. Using genome data from cyanobacteria and archaea, it is found that the likelihood is significantly improved by allowing for multiple gains, but the average a/v is very small. The fraction of genes whose presence/absence pattern is best explained by multiple gains is only 15% in the cyanobacteria and 20% and 39% in two data sets of archaea. The distribution of rates of gene loss is very broad, which explains why many genes follow a treelike pattern of vertical inheritance, despite the presence of a significant minority of genes that undergo horizontal transfer.

Endoscopic endonasal multilayer repair of traumatic CSF rhinorrhea.

The incidence of traumatic CSF has increased in recent years due to increased incidence of road traffic accidents (RTA) as well the increasing number of endoscopic sinus surgeries (ESS). The objective of this study is to present our experience in management of traumatic CSF leaks using the endoscopic multilayer repair technique. Forty-two patients (aged 10-75 years, 30 males and 12 females) presenting with confirmed post-traumatic CSF rhinorrhea were operated upon between January 2007 and December 2013. The endoscopic multilayer technique was used in all cases. Electromagnetic navigation was used in some cases. All cases presented with intermittent watery rhinorrhea. The duration of the rhinorrhea ranged from 3 days to 1 year before repair. One case presented after 10 years from the causative trauma. Ten cases had a history of meningitis. Nine cases had more than one defect. Iatrogenic defects were larger than defects following accidental trauma. Two cases, following RTA, developed pseudo-aneurysm of internal carotid artery. Ten cases had associated pneumocephalus. The mean duration of postoperative hospitalization was 6 days (range 4-8 days). The mean follow-up duration was 31.2 +/- 11.4 months (range 16-48 months). None of our patient developed serious intra- or postoperative complications. Only one case required another surgery to repair a missed second defect. Post-traumatic CSF leaks can be successfully managed via the endonasal endoscopic route using the multilayer repair technique. It is important to look for multiple defects in these cases. CT angiography is recommended for traumatic leaks involving the lateral wall of the sphenoid sinus to diagnose or exclude the development of pseudo-aneurysm of the internal carotid artery.