Ioannis P. Fouyas

Cochrane review on the role of surgery in cervical spondylotic radiculomyelopathy.

Study Design. This study involved a search of MEDLINE (1966 to 2000), EMBASE (1980 to 2000), and the Cochrane Controlled Trials Register. The authors of the identified randomized controlled trials were contacted to detect any additional published or unpublished data. The trials selected for this study included all the truly unconfounded or quasi-randomized controlled investigations allocating patients with cervical radiculopathy or myelopathy to 1) “best medical management” or “decompressive surgery (with or without some form of fusion) plus best medical management,” or 2) “early decompressive surgery” or “delayed decompressive surgery.” Two reviewers independently selected trials for inclusion, assessed trial quality, and extracted the data. Objectives. To determine whether surgical treatment of cervical radiculopathy or myelopathy is associated with improved outcome, as compared with conservative management, and whether the timing of surgery (immediate or delayed because of persistence or progression of relevant symptoms and signs) has an impact on outcome. Summary of Background Data. Cervical spondylosis causes pain and disability by compressing the spinal cord or roots. Surgery to relieve the compression may reduce the pain and disability. However, it is associated with a small but definite risk. This study sought to assess the balance of risk and benefit from surgery. Methods. Two trials involving a total of 130 patients were included. One trial with 81 patients compared surgical decompression with either physiotherapy or cervical collar immobilization in patients with cervical radiculopathy. Results. The short-term effects of surgery, in terms of pain, weakness, or sensory loss were superior. However, at 1 year no significant differences between the groups were observed. Another trial with 49 patients compared the effects of surgery with those of conservative treatment in patients who had a mild functional deficit associated with cervical myelopathy. No significant differences were observed between the groups up to 2 years after treatment. Conclusions. The data from the reviewed trials were inadequate to provide reliable conclusions on the balance of risk and benefit from cervical spine surgery for spondylotic radiculopathy or myelopathy.

Postoperative spinal epidural hematoma (SEH): incidence, risk factors, onset, and management

BACKGROUND CONTEXT Spinal epidural hematoma (SEH) is a rare, yet potentially devastating complication of spinal surgery. There is limited evidence available regarding the risk factors and timing for development of symptomatic SEH after spinal surgery. PURPOSE To assess the incidence, risk factors, time of the onset, and effect of early evacuation of symptomatic SEH after spinal surgery. STUDY DESIGN Multicenter case control study. PATIENT SAMPLE All patients who underwent open spinal surgery between October 1, 1999, and September 30, 2006, at the National Hospital For Neurology and Neurosurgery (NHNN) and the Wellington Hospital (WH) were reviewed. OUTCOME MEASURES Frankel grade. METHODS Patients who developed SEH and underwent evacuation of the hematoma were identified. Two controls per case were selected. Each control had undergone a procedure with similar complexity, at the same section of the spine, at the same hospital, and under the same surgeon within 6 months of the initial operation. RESULTS A total of 4,568 open spinal operations were performed at NHNN and WH. After spinal surgery, 0.22% of patients developed symptomatic SEH. Alcohol greater than 10 units a week (p=.031), previous spinal surgery (p=.007), and multilevel procedures (p=.002) were shown to be risk factors. Initial symptoms of SEH presented after a median time of 2.7 hours (interquartile range [IQR], 1.1-126.1). Patients who had evacuation surgery within 6 hours of the onset of initial symptoms improved a median of 2 (IQR, 1.0-3.0) Frankel grades, and those who had surgery more than 6 hours after the onset of symptoms improved 1.0 (IQR, 0.0-1.5) Frankel grade, p=.379. CONCLUSIONS Symptomatic postoperative SEH is rare, occurring in 0.22% of cases. Alcohol consumption greater than 10 units a week, multilevel procedure, and previous spinal surgery were identified as risk factors for developing SEH. Spinal epidural hematoma often presents early in the postoperative period, highlighting the importance of close patient monitoring within the first 4 hours after surgery. This study suggests that earlier surgical intervention may result in greater neurological recovery.

Efficacy, complications and cost of surgical interventions for idiopathic intracranial hypertension: a systematic review of the literature

BackgroundTo define the efficacy, complication profile and cost of surgical options for treating idiopathic intracranial hypertension (IIH) with respect to the following endpoints: vision and headache improvement, normal CSF pressure restoration, papilloedema resolution, relapse rate, operative complications, cost of intervention and quality of life.MethodsA systematic review of the surgical treatment of IIH was carried out. Cochrane Library, MEDLINE and EMBASE databases were systematically searched from 1985 to 2014 to identify all relevant manuscripts written in English. Additional studies were identified by searching the references of retrieved papers and relative narrative reviews.ResultsForty-one (41) studies were included (36 case series and 5 case reports), totalling 728 patients. Three hundred forty-one patients were treated with optic nerve sheath fenestration (ONSF), 128 patients with lumboperitoneal shunting (LPS), 72 patients with ventriculoperitoneal shunting (VPS), 155 patients with venous sinus stenting and 32 patients with bariatric surgery. ONSF showed considerable efficacy in vision improvement, while CSF shunting had a superior headache response. Venous sinus stenting demonstrated satisfactory results in both vision and headache improvement along with the best complication profile and low relapse rate, but longer follow-up periods are needed. The complication rate of bariatric surgery was high when compared to other interventions and visual outcomes have not been reported adequately. ONSF had the lowest cost.ConclusionsNo surgical modality proved to be clearly superior to any other in IIH management. However, in certain contexts, a given approach appears more justified. Therefore, a treatment algorithm has been formulated, based on the extracted evidence of this review. The traditional treatment paradigm may need to be re-examined with sinus stenting as a first-line treatment modality.

Cerebrovascular effects of nitric oxide manipulation in spontaneously hypertensive rats

Evidence that nitric oxide (NO) bioactivity is altered in chronic hypertension is conflicting, possibly as a result of heterogeneity in both the nature of the dysfunction and in the disease process itself. The brain is particularly vulnerable to the vascular complications of chronic hypertension, and the aim of this study was to assess whether differences in the cerebrovascular responsiveness to the NO synthase (NOS) inhibitors, NG‐nitro‐L‐arginine methyl ester (L‐NAME) and 7‐nitroindazole (7‐NI), and to the NO donor 3‐morpholinosydnonimine (SIN‐1) might indicate one possible source of these complications. Conscious spontaneously hypertensive (SHR) and WKY rats, were treated with L‐NAME (30 mg kg−1, i.v.), 7‐NI (25 mg kg−1, i.p.), SIN‐1 (0.54 or 1.8 mg kg−1 h−1, continuous i.v. infusion) or saline (i.v.), 20 min before the measurement of local cerebral blood flow (LCBF) by the fully quantitative [14C]‐iodoantipyrine autoradiographic technique. With the exception of mean arterial blood pressure (MABP), there were no significant differences in physiological parameters between SHR and WKY rats within any of the treatment groups, or between treatment groups. L‐NAME treatment increased MABP by 27% in WKY and 18% in SHR groups, whilst 7‐NI had no significant effect in either group. Following the lower dose of SIN‐1 infusion, MABP was decreased to a similar extent in both groups (around −20%). There was no significant difference in MABP between groups following the higher dose of SIN‐1, but this represented a decrease of −41% in SHR and −21% in WKY rats. With the exception of one brain region (nucleus accumbens), there were no significant differences in basal LCBF between WKY and SHR. L‐NAME produced similar decreases in LCBF in both groups, ranging between −10 and −40%. The effect of 7‐NI upon LCBF was more pronounced in the SHR (ranging from −34 to −57%) compared with the WKY (ranging from −14 to −43%), and in seven out of the thirteen brain areas examined there were significant differences in LCBF. Following the lower dose of SIN‐1, in the WKY 8 out of the 13 brain areas examined showed significant increases in blood flow compared to the saline treated animals. In contrast, only 2 brain areas showed significant increases in flow in the SHR. In the rest of the brain areas examined the effects of SIN‐1 upon LCBF were less marked than in the WKY. Infusion of the higher dose of SIN‐1 resulted in further significant increases in LCBF in the WKY group (ranging between +30% and +74% compared to saline‐treated animals), but no significant effects upon LCBF were found in the SHR. As a result, there were significant differences in LCBF between SIN‐1‐treated WKY and SHR in six brain areas. In most brain areas examined, cerebral blood flow in SHR following the higher dose of SIN‐1 was less than that measured with the lower dose of SIN‐1. Despite comparable reductions in MABP (∼20%) in both groups, calculated cerebrovascular resistance (CVR) confirmed that the vasodilator effects of the lower dose of SIN‐1 were significantly more pronounced throughout the brain in the WKY (ranging between −3% and −50%; median=−38%) when compared to the SHR (ranging between −10% and −36%; median=−26%). In the animals treated with the higher dose of SIN‐1, CVR changes were broadly similar in both groups (median=−45% in WKY and −42% in SHR), but with the reduction in MABP in SHR being twice that found in WKY, this is in keeping with an attenuated blood flow response to SIN‐1 in the SHR. The results of this study indicate that NO‐dependent vasodilator capacity is reduced in the cerebrovasculature of SHR. In addition, the equal responsiveness to a non‐specific NOS inhibitor but an enhanced effectiveness of a specific neuronal NO inhibitor upon LCBF in the SHR could be consistent with an upregulation of the neuronal NO system.

Validating the use of smartphone-based accelerometers for performance assessment in a simulated neurosurgical task.

BACKGROUND: Reductions in working hours affect training opportunities for surgeons. Surgical simulation is increasingly proposed to help bridge the resultant training gap. For simulation training to translate effectively into the operating theater, acquisition of technical proficiency must be objectively assessed. Evaluating “economy of movement” is one way to achieve this. OBJECTIVE: We sought to validate a practical and economical method of assessing economy of movement during a simulated task. We hypothesized that accelerometers, found in smartphones, provide quantitative, objective feedback when attached to a neurosurgeons wrists. METHODS: Subjects (n = 25) included consultants, senior registrars, junior registrars, junior doctors, and medical students. Total resultant acceleration (TRA), average resultant acceleration, and movements with acceleration >0.6g (suprathreshold acceleration events) were recorded while subjects performed a simulated dural closure task. RESULTS: Students recorded an average TRA 97.0 ± 31.2 ms−2 higher than senior registrars (P = .03) and 103 ± 31.2 ms−2 higher than consultants (P = .02). Similarly, junior doctors accrued an average TRA 181 ± 31.2 ms−2 higher than senior registrars (P < .001) and 187 ± 31.2 ms−2 higher than consultants (P < .001). Significant correlations were observed between surgical outcome (as measured by quality of dural closure) and both TRA (r = .44, P < .001) and number of suprathreshold acceleration events (r = .33, P < .001). TRA (219 ± 66.6 ms−2; P = .01) and number of suprathreshold acceleration events (127 ± 42.5; P = .02) dropped between the first and fourth trials for junior doctors, suggesting procedural learning. TRA was 45.4 ± 17.1 ms−2 higher in the dominant hand for students (P = .04) and 57.2 ± 17.1 ms−2 for junior doctors (P = .005), contrasting with even TRA distribution between hands (acquired ambidexterity) in senior groups. CONCLUSION: Data from smartphone-based accelerometers show construct validity as an adjunct for assessing technical performance during simulation training. ABBREVIATIONS: ARA, average resultant acceleration FY, foundation-year doctor JR, junior registrar SR, senior registrar STAE, suprathreshold acceleration events TRA, total resultant acceleration

Cerebrovascular responses to pathophysiological insult in diabetic rats.

Diabetes mellitus is associated with altered cerebrovascular responsiveness and this could contribute to the pathology of stroke in diabetic patients. In these studies, we used a model of haemorrhagic stroke (intrastriatal injection of 50 microl blood) to examine subacute perilesional perfusion and blood-brain barrier (BBB) integrity in spontaneously diabetic rats. Volumes of striatal oligaemia (blood flow < 35 ml 100 g(-1) min(-1)) were significantly increased (>300%) in diabetic rats with intrastriatal blood, compared to either non-diabetic rats with blood or control diabetic rats with striatal injection of silicon oil. However, the increase in BBB permeability was both qualitatively and quantitatively similar in diabetic and control rats. Poorer outcomes following haemorrhagic stroke in diabetic patients may thus result from dysfunctional cerebrovascular control, and particularly decreased dilatatory reserve.

Cerebrovascular responsiveness to NG-nitro-L-arginine methyl ester in spontaneously diabetic rats.

1 There is evidence that endothelial dysfunction is associated with diabetes mellitus. The purpose of the present study was to assess local cerebral blood flow (LCBF) and cerebrovascular responsiveness to the NOS inhibitor NG‐nitro‐L‐arginine methyl ester (L‐NAME) in spontaneously diabetic insulin‐dependent BioBred (BB) rats. 2 Diabetic rats, and non‐diabetic controls, were treated with L‐NAME (30 mg kg−1, i.v.) or saline, 20 min prior to the measurement of LCBF by the fully quantitative [14C]‐iodoantipyrine autoradiographic technique. 3 There were no significant differences in physiological parameters (blood pH, pH, PCO2, and PO2, rectal temperature, arterial blood pressure, or plasma glucose) between any of the groups of rats, and no difference in either the extent or the temporal characteristics of the hypertensive response to L‐NAME between diabetic and non‐diabetic rats. 4 In diabetic rats, a global reduction in basal LCBF was observed, although significant reductions (between −20 and −30%) were found in only 5 (mainly subcortical) out of the 13 brain regions measured. Following L‐NAME injection, significant reductions in LCBF (between −20 and −40%) were found in the non‐diabetic animals. In diabetic animals treated with L‐NAME, a significant reduction in LCBF was measured only in the hypothalamus (−33%). 5 The cerebrovascular response to acute L‐NAME is attenuated in spontaneously diabetic insulin‐dependent BB rats. This would be consistent with the endothelial dysfunction in cerebral vessels, known to be associated with diabetes mellitus and it is possible that a loss of NO‐induced dilator tone, amongst other factors, may underlie the observed reductions of basal LCBF in these animals.

Publication fate of abstracts presented at Society of British Neurological Surgeons meetings.

Abstract Introduction. Society of British Neurological Surgeons (SBNS) meetings are important national events which allow for the presentation of current academic work. The publication rate of presented abstracts is considered a proxy marker of the scientific strength of a conference. We aimed to determine the publication fate of presented abstracts at SBNS meetings over a 5-year period. Methods. A retrospective review of SBNS conference proceedings between 2001 and 2005 was performed. To ascertain whether an abstract resulted in peer-reviewed publication, a range of databases (PubMed, Google Scholar, Medline and Ovid) were interrogated. Abstracts published in full were subsequently assessed for journal impact factor (IF), time of publication and number of citations received (per Google Scholar). Results. A total of 494 abstracts were presented. Of these, 181 abstracts were subsequently published in full, giving the conference a publication rate of 36.6%. The mean time to publication from presentation was 22 months (range 35 months pre-presentation to 133 months afterwards). The top three journals for publication were the British Journal of Neurosurgery (23.2%), Neurosurgery (7.7%) and Journal of Neurosurgery (7.7%). The IF of journal destinations ranged from no IF to 38.28 (median = 1.97). Number of citations ranged from 0 to 963 (median = 22). Abstracts with positive results were significantly more likely to be published in full compared to those with negative results (p = 0.0001). Conclusions. SBNS conferences have a respectable publication rate. Those abstracts that are published in full have gone on to gain a considerable number of citations reflecting their scientific relevance. However, studies presented at SBNS are susceptible to positive outcome bias.

Intra-operative localisation of spinal level using pre-operative CT-guided placement of a flexible hook-wire marker.

Confident intra-operative localisation of thoracic spinal pathology remains challenging. Several strategies are routinely employed, including intra-operative fluoroscopy and pre-operative image-guided skin marking. These techniques are limited both by potential inaccuracy and inconvenience. Here we present a novel, efficient and accurate technique for intra-operative localisation of thoracic spinal pathology using pre-operative CT-guided placement of a flexible hook-wire marker.

Spontaneous subdural haematoma in a healthy young male

The authors present an unusual case of a healthy young male who developed a spontaneous subdural haematoma. Headache was followed by blurring of vision and left upper limb symptoms. The diagnosis was made from a CT scan. Symptoms resolved with surgical decompression. The authors explore the risk factors and pathophysiology implicated in this condition. The authors demonstrate that apparently ‘healthy’ pursuits can have significant consequences, but the physician must also exclude serious underlying risk factors for bleeding, which the authors discuss.