Although he was not the first man to operate on the brain, Sir Victor Horsley was the world's first surgeon appointed to a hospital post to perform brain surgery, which happened in 1886 at the National Hospital for Neurology and Neurosurgery, Queen Square, London. The authors examined the patient records between 1886 and 1899 and found 151 operations performed by Sir Victor Horsley at the National Hospital, including craniotomies, laminectomies, and nerve divisions. The authors present the outcome data and case illustrations of cerebral tumor resections and laminectomies from the nineteenth century. Outcomes and notable pioneering achievements are highlighted.
Christopher Uff, Daniel Frith, Catriona Harrison, Michael Powell and Neil Kitchen
Harith Akram, Bilal Mirza, Neil Kitchen and Joanna M. Zakrzewska
The aim of this study was to design a checklist with a scoring system for reporting on studies of surgical interventions for trigeminal neuralgia (TN) and to validate it by a review of the recent literature.
A checklist with a scoring system, the Surgical Trigeminal Neuralgia Score (STNS), was devised partially based on the validated STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) criteria and customized for TN after a literature review and then applied to a series of articles. These articles were identified using a prespecified MEDLINE and Embase search covering the period from 2008 to 2010. Of the 584 articles found, 59 were studies of interventional procedures for TN that fulfilled the inclusion criteria and 56 could be obtained in full. The STNS was then applied independently by 3 of the authors.
The maximum STNS came to 30, and was reliable and reproducible when used by the 3 authors who performed the scoring. The range of scores was 6–23.5, with a mean of 14 for all the journals. The impact factor scores of the journals in which the papers were published ranged from 0 to 4.8. Twenty-four of the studies were published in the Journal of Neurosurgery or in Neurosurgery. Studies published in neurosurgical journals ranked higher on the STNS scale than those published in nonneurosurgical journals. There was no statistically significant correlation between STNS and impact factors. Stereotactic radiosurgery (n = 25) and microvascular decompression (n = 15) were the most commonly reported procedures.
The diagnostic criteria were stated in 35% of the studies, and 4 studies reported subtypes of TN. An increasing number of studies (46%) used the recommended Kaplan-Meier methodology for pain survival outcomes. The follow-up period was unclear in 8 studies, and 26 reported follow-ups of more than 5 years. Complications were reported fairly consistently but the temporal course was not always indicated. Direct interview, telephone conversation, and questionnaires were used to measure outcomes. Independent assessment of outcome was only clearly stated in 7 studies. Only 2 studies used the 36-Item Short Form Health Survey to measure quality of life and 4 studies reported on the severity of preoperative pain. The Barrow Neurological Institute pain questionnaire was the most commonly used outcome measure (n = 13), followed by the visual analog scale.
Similar to the STROBE criteria that provide a checklist of items that should be included in reports of observational studies in general, the authors' suggested checklist for the STNS could help editors and reviewers ensure that quality reports are published, and could prove useful for colleagues when reporting their results specifically on the surgical management of TN. It would help the patient and clinicians make a decision about selecting the appropriate neurosurgical procedure.
Andrew Tarnaris, Neil D. Kitchen and Laurence D. Watkins
Normal pressure hydrocephalus (NPH) represents a treatable form of dementia. Recent estimates of the incidence of this condition are in the region of 5% of patients with dementia. The symptoms of NPH can vary among individuals and may be confused with those of patients with multi-infarct dementia, dementia of the Alzheimer type, or even Parkinson disease. Traditionally the diagnosis of NPH could only be confirmed postoperatively by a favorable outcome to surgical diversion of CSF. The object of this literature review was to examine the role of structural and functional imaging in providing biomarkers of favorable surgical outcome.
A Medline search was undertaken for the years 1980–2006, using the following terms: normal pressure hydrocephalus, adult hydrocephalus, chronic hydrocephalus, imaging, neuroimaging, imaging studies, outcomes, surgical outcomes, prognosis, prognostic value, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy.
The query revealed 16 studies that correlated imaging with surgical outcomes offering accuracy results. Three studies fulfilled the statistical criteria of a biomarker. A dementia Alzheimer-type pattern on SPECT in patients with idiopathic NPH, the presence of CSF flow void on MR imaging, and the N-acetylaspartate/choline ratio in patients with the secondary form are able to predict surgical outcomes with high accuracy.
There is at present Level A evidence for using MR spectroscopy in patients with secondary NPH, and Level B evidence for using SPECT and phase-contrast MR imaging to select patients with idiopathic NPH for shunt placement. The studies, however, need to be repeated by other groups. The current work should act as a platform to design further studies with larger sample sizes.
Neil L. Dorward, Olaf Alberti, James D. Palmer, Neil D. Kitchen and David G. T. Thomas
✓ The authors present the results of accuracy measurements, obtained in both laboratory phantom studies and an in vivo assessment, for a technique of frameless stereotaxy. An instrument holder was developed to facilitate stereotactic guidance and enable introduction of frameless methods to traditional frame-based procedures. The accuracy of frameless stereotaxy was assessed for images acquired using 0.5-tesla or 1.5-tesla magnetic resonance (MR) imaging or 2-mm axial, 3-mm axial, or 3-mm helical computerized tomography (CT) scanning. A clinical series is reported in which biopsy samples were obtained using a frameless stereotactic procedure, and the accuracy of these procedures was assessed using postoperative MR images and image fusion.
The overall mean error of phantom frameless stereotaxy was found to be 1.3 mm (standard deviation [SD] 0.6 mm). The mean error for CT-directed frameless stereotaxy was 1.1 mm (SD 0.5 mm) and that for MR image—directed procedures was 1.4 mm (SD 0.7 mm). The CT-guided frameless stereotaxy was significantly more accurate than MR image—directed stereotaxy (p = 0.0001). In addition, 2-mm axial CT-guided stereotaxy was significantly more accurate than 3-mm axial CT-guided stereotaxy (p = 0.025). In the clinical series of 21 frameless stereotactically obtained biopsies, all specimens yielded the appropriate diagnosis and no complications ensued. Early postoperative MR images were obtained in 16 of these cases and displacement of the biopsy site from the intraoperative target was determined by fusion of pre- and postoperative image data sets. The mean in vivo linear error of frameless stereotactic biopsy sampling was 2.3 mm (SD 1.9 mm). The mean in vivo Euclidean error was 4.8 mm (SD 2 mm). The implications of these accuracy measurements and of error in stereotaxy are discussed.
Ahmed K. Toma, Andrew Tarnaris, Joan P. Grieve, Laurence D. Watkins and Neil D. Kitchen
In this paper, the authors' goal was to compare the artifact induced by implanted (in vivo) adjustable shunt valves in spin echo, diffusion weighted (DW), and gradient echo MR imaging pulse sequences.
The MR images obtained in 8 patients with proGAV and 6 patients with Strata II adjustable shunt valves were assessed for artifact areas in different planes as well as the total volume for different pulse sequences.
Artifacts induced by the Strata II valve were significantly larger than those induced by proGAV valve in spin echo MR imaging pulse sequence (29,761 vs 2450 mm3 on T2-weighted fast spin echo, p = 0.003) and DW images (100,138 vs 38,955 mm3, p = 0.025). Artifacts were more marked on DW MR images than on spin echo pulse sequencse for both valve types.
Adjustable valve–induced artifacts can conceal brain pathology on MR images. This should influence the choice of valve implantation site and the type of valve used. The effect of artifacts on DW images should be highlighted pending the development of less MR imaging artifact–inducing adjustable shunt valves.
Andrew Tarnaris, Ahmed. K. Toma, Miles D. Chapman, Geoff Keir, Neil D. Kitchen and Laurence D. Watkins
The prognostic value of CSF biomarkers in patients with idiopathic normal pressure hydrocephalus (iNPH) has not been adequately studied to date. The aim of this study was to identify CSF markers of favorable surgical outcome in patients with iNPH undergoing the insertion of a ventriculoperitoneal shunt.
Ventricular CSF was collected intraoperatively from 22 patients with iNPH and enzyme-linked immunosorbent assay was used to analyze the levels of amyloid-β 1–42 (Aβ1–42) and total tau protein. The Black grading scale was used to assess outcomes at 6 months. Receiver operating characteristic (ROC) curves were obtained and discriminant function analysis was undertaken to provide sensitivity and specificity figures for each marker as well as their combination.
The mean age of the patients was 71.45 years (± 9.5 years [SD]). Follow-up was achieved in 21 patients. Seventeen patients had a favorable outcome and 4 patients had unfavorable outcome at 6 months. An Aβ1–42 level of 180 pg/ml had a sensitivity of 35% and a specificity of 20% for predicting a favorable outcome at 6 months. A total tau level of 767 pg/ml will have a sensitivity of 17% and a specificity of 20% for predicting a favorable outcome at 6 months. A combination of Aβ1–42 and total tau levels predicted favorable outcomes with a sensitivity of 80% and specificity of 82.4%.
In this pilot study a combination of Aβ1–42 levels and total tau protein levels predicted favorable surgical outcomes at 6 months with adequate accuracy to be of clinical use. Further study in a larger group with longer follow-up is warranted.
Marco Schiariti, Pablo Goetz, Hussien El-Maghraby, Jignesh Tailor and Neil Kitchen
Hemangiopericytomas are rare tumors that behave aggressively with a high rate of local recurrence and distant metastases. With the aim of determining the outcome and response to various treatment modalities, a series of 39 patients who underwent microsurgical resection for primary meningeal hemangiopericytoma over a 24-year period is presented.
Patients with hemangiopericytoma were identified from histopathology records and their medical records were analyzed retrospectively by 2 independent reviewers to collect data on surgical treatment, adjuvant therapy, postoperative course, local or distant recurrence, and follow-up.
Of the 39 patients, 19 were male and 20 were female. Mean patient age was 44.1 years. Thirty-four tumors were intracranial and 5 were spinal. The mean follow-up period was 123 months. Twenty-eight patients developed local recurrence. The recurrence rate at 1, 5, and 15 years was 3.5%, 46%, and 92%, respectively. Extraneural metastasis occurred in 8 patients (26%) at an average of 123 months after initial surgery. Recurrences and metastases were treated by surgical excision, external beam radiation therapy (EBRT), chemotherapy, and/or stereotactic radiosurgery. Adjuvant EBRT following initial surgery was found to extend the disease-free interval from 154 months to 254 months, although it did not prevent the development of metastasis. In those patients with EBRT and complete resection, the mean recurrence-free interval was found to be 126.3 months longer (p = 0.04) and overall survival 126 months longer than without EBRT. Furthermore, adjusting for resection, patients undergoing EBRT had 0.33 times increased risk of recurrence compared with those who did not (p = 0.03). A majority of patients remained able to live independently despite revision surgery for recurrence.
The mean follow-up of this patient series represents the longest follow-up duration published to date and demonstrates extended survival in a significant number of patients with hemangiopericytoma. Gross-total resection followed by adjuvant EBRT provides patients with the highest probability of an increased recurrence-free interval and overall survival. Prolonged survival justifies long-term follow-up and aggressive treatment of initial, recurrent, and metastatic disease.
Ahmed K. Toma, Muhammad Dherijha, Neil D. Kitchen and Laurence D. Watkins
The lumboperitoneal (LP) shunt with the adjustable PS Medical Strata NSC LP valve and small lumen peritoneal catheter was introduced in the authors' unit in 2007. The object of this study was to audit the unit's experience with this new shunt system.
The authors performed a retrospective review of the clinical records of patients who underwent Strata NSC LP shunt insertion. Demographic and clinical data as well as information about complications and revisions were reported.
Between August 2007 and November 2009, 20 patients underwent placement of an LP shunt with an adjustable Strata NSC valve and small lumen peritoneal catheter at the authors' institution. Their mean age was 40.3 years and the mean duration of follow-up was 12 months. Preoperatively, 18 patients had headache and 15 patients had visual signs and symptoms. Fourteen of the 18 patients with preoperative headache did not complain of headache postoperatively, and 4 had headache that was found not to be related to shunt function. Two of the patients with preoperative visual complaints had ongoing visual problems postoperatively. None of the patients had infection or subdural hematoma. The only overdrainage symptoms occurred in association with spontaneous readjustment of the valve and resolved when the valve was reset.
Thirteen patients (65%) did not require shunt revision. Seven patients (35%) required 13 shunt exploration or revision procedures, mainly due to distal obstruction. Placement of an LP shunt failed to completely resolve the raised intracranial pressure problem in 2 patients.
The use of the Strata NSC valve and small lumen peritoneal catheter is effective in treating pseudotumor cerebri and is beneficial in terms of markedly reducing overdrainage complications compared with other reported series of cases in which an LP shunt has been placed. However, the use of the Strata NSC valve and small lumen peritoneal catheter did not have a marked impact on other causes of shunt failure, particularly distal obstruction.
Ahmed K. Toma, Andrew Tarnaris, Neil D. Kitchen and Laurence D. Watkins
Managing symptomatic ventriculoperitoneal shunts with no clear evidence of shunt malfunction either clinically or radiologically can be a difficult task. The aim of this study was to assess intracranial pressure (ICP) monitoring as a method of investigating shunt function.
The authors performed a retrospective analysis of 38 continuous ICP monitoring procedures done in patients with ventriculoperitoneal shunts and suspected shunt malfunction.
Thirty-eight procedures were performed in 31 patients between January 2005 and October 2008. Sixteen recordings were normal, 6 revealed overdrainage or low pressure, 11 indicated underdrainage or high pressure, and 5 showed variable shunt function. Based on the findings after 20 procedures (53%), patients were treated conservatively: 4 by readjusting the valve setting and 16 by referral to the headache neurologist for medical treatment. Forty-five percent of the conservatively treated patients improved. Surgical exploration was undertaken following 18 procedures (47%); 72% of the surgically treated patients improved.
Continuous ICP monitoring using an intraparenchymal probe is a safe and effective method of investigating adult hydrocephalus.
Fiona A. Wilkes, Harith Akram, Jonathan A. Hyam, Neil D. Kitchen, Marwan I. Hariz and Ludvic Zrinzo
Bibliometrics are the methods used to quantitatively analyze scientific literature. In this study, bibliometrics were used to quantify the scientific output of neurosurgical departments throughout Great Britain and Ireland.
A list of neurosurgical departments was obtained from the Society of British Neurological Surgeons website. Individual departments were contacted for an up-to-date list of consultant (attending) neurosurgeons practicing in these departments. Scopus was used to determine the h-index and m-quotient for each neurosurgeon. Indices were measured by surgeon and by departmental mean and total. Additional information was collected about the surgeon's sex, title, listed superspecialties, higher research degrees, and year of medical qualification.
Data were analyzed for 315 neurosurgeons (25 female). The median h-index and m-quotient were 6.00 and 0.41, respectively. These were significantly higher for professors (h-index 21.50; m-quotient 0.71) and for those with an additional MD or PhD (11.0; 0.57). There was no significant difference in h-index, m-quotient, or higher research degrees between the sexes. However, none of the 16 British neurosurgery professors were female. Neurosurgeons who specialized in functional/epilepsy surgery ranked highest in terms of publication productivity. The 5 top-scoring departments were those in Addenbrooke's Hospital, Cambridge; St. George's Hospital, London; Great Ormond Street Hospital, London; National Hospital for Neurology and Neurosurgery, Queen Square, London; and John Radcliffe Hospital, Oxford.
The h-index is a useful bibliometric marker, particularly when comparing between studies and individuals. The m-quotient reduces bias toward established researchers. British academic neurosurgeons face considerable challenges, and women remain underrepresented in both clinical and academic neurosurgery in Britain and Ireland.