Safety for cervical corpectomy and diskectomy: univariate and multivariate analysis on predictors for prolonged ICU stay after anterior spinal fusion.

AIM: Cervical anterior spinal fusion (ASF) with corpectomy has risks of catastrophic acute complications such as airway obstruction requiring re-intubation. Our team has adopted a management plan for all cervical corpectomy patients to be admitted to the intensive care unit (ICU) after the operations for overnight observation. Some of these patients were kept intubated after the operations and transferred to the ICU. This study aims to review the outcome of this practice and to identify independent predictors associated with a prolonged ICU stay. METHODS: We reviewed consecutive patients with cervical ASF from January 2010 to June 2018. The primary outcome was the ICU length of stay. Univariate and multivariate analyses were conducted to identify independent risk factors associated with a prolonged ICU stay. In total, 103 patients had ASF during the study period. ICU length of stay for elective ASF was 1.01 day (SD 0.373 days) and was significantly shorter than that for emergency ASF (13.29 days, SD 12.57 days) (p < 0.001). 79.6% (82/103) of the ASF patients were extubated in the operating theatre after surgery. Significantly more corpectomy patients (33.3%) versus ACDF patients (15.1%) were kept intubated to the ICU after the operation (p = 0.037). None required reintubation in the ICU. 90.9% (80/88) of the elective ASF can be discharged from the ICU within 24 hours and only 3.41% (3/88) of the elective ASF had prolonged post-operative stay in the ICU (≥48 hours). RESULTS: For prolonged postoperative ICU stay (≥48 hours), ICU admission airway status of ASF patients who were either extubated in the OT or kept intubated to ICU had no significant association (p = 0.903). Univariate and multivariate analysis had identified emergency admissions (p = 0.043) and the presence of postoperative neurological deficits (p = 0.031) as independent predictors associated with a prolonged postoperative ICU stay. CONCLUSION: In conclusion, cervical corpectomy and ASF were safe with minimal acute complications.

Elderly population have a decreased aneurysmal subarachnoid hemorrhage incidence rate than Middle aged population: a descriptive analysis of 8,144 cases in mainland China.

PURPOSE: Rupture of an intracranial aneurysm is a life-threatening acute cerebrovascular event. The purpose of this study was to investigate whether aneurysmal subarachnoid haemorrhage (SAH) incidence rate is higher or lower in elderly population than in middle aged population. MATERIALS AND METHODS: Aneurysmal SAH cases were collected retrospectively from the archives of 21 hospitals in Mainland China. All the cases were collected from September 2016 and backward consecutively for a period of time up to 8 years. SAH was initially diagnosed by brain computed tomography (CT). CT angiography (CTA) or digital subtraction angiography (DSA) was followed and SAH was confirmed to be due to cerebral aneurysm rupture. For cases when multiple bleeding occurred, the age of the first SAH was used in this study. The total incidence from all hospitals at each age group were summed together for females and males respectively; then adjusted by the total population number at each age group for females and males which was from the 2010 population census of the People's Republic of China. RESULTS: In total there were 8,144 cases of intracranial aneurysmal SAH, with 4,861 females and 3,283 males. For females the relative aneurysmal SAH incidence rate started to decrease after around 65 years old, while for males the relative aneurysmal SAH incidence rate started to decrease after around 53 years old. CONCLUSION: Our data tentatively suggest elderly patients may be at a reduced risk of rupture compared with patients who are younger while have similar other risk factors.

Interactome and reciprocal activation of pathways in topical mesenchymal stem cells and the recipient cerebral cortex following traumatic brain injury.

In this study, GFP-MSCs were topically applied to the surface of cerebral cortex within 1 hour of experimental TBI. No treatment was given to the control group. Three days after topical application, the MSCs homed to the injured parenchyma and improved the neurological function. Topical MSCs triggered earlier astrocytosis and reactive microglia. TBI penumbra and hippocampus had higher cellular proliferation. Apoptosis was suppressed at hippocampus at 1 week and reduced neuronal damaged was found in the penumbral at day 14 apoptosis. Proteolytic neuronal injury biomarkers (alphaII-spectrin breakdown products, SBDPs) and glial cell injury biomarker, glial fibrillary acidic protein (GFAP)-breakdown product (GBDPs) in injured cortex were also attenuated by MSCs. In the penumbra, six genes related to axongenesis (Erbb2); growth factors (Artn, Ptn); cytokine (IL3); cell cycle (Hdac4); and notch signaling (Hes1) were up-regulated three days after MSC transplant. Transcriptome analysis demonstrated that 7,943 genes were differentially expressed and 94 signaling pathways were activated in the topical MSCs transplanted onto the cortex of brain injured rats with TBI. In conclusion, topical application offers a direct and efficient delivery of MSCs to the brain.

MicroRNA-182 Regulates Neurite Outgrowth Involving the PTEN/AKT Pathway.

MicroRNAs are implicated in neuronal development and maturation. Neuronal maturation, including axon outgrowth and dendrite tree formation, is regulated by complex mechanisms and related to several neurodevelopmental disorders. We demonstrated that one neuron-enriched microRNA, microRNA-182 (miR-182), played a significant role in regulating neuronal axon outgrowth and dendrite tree formation. Overexpression of miR-182 promoted axon outgrowth and complexity of the dendrite tree while also increasing the expression of neurofilament-M and neurofilament-L, which provide structural support for neurite outgrowth. However, a reduction of miR-182 inhibited neurite outgrowth. Furthermore, we showed that miR-182 activated the AKT pathway by increasing AKT phosphorylation on S473 and T308 and inhibiting PTEN activity by increasing phosphorylation on S380. Inhibition of AKT activity with the PI3-K inhibitor LY294002 could downregulate AKT and PTEN phosphorylation and suppress axon outgrowth. In addition, we showed that BCAT2 might be the target of miR-182 that takes part in the regulation of neuronal maturation; blockage of endogenous BCAT2 promotes axon outgrowth and AKT activity. These observations indicate that miR-182 regulates axon outgrowth and dendrite maturation involving activation of the PTEN/AKT pathway.

Pattern of recurrence and factors associated with cerebrospinal fluid dissemination of glioblastoma in Chinese patients.

BACKGROUND: Pattern of recurrence of glioblastoma (GBM) seems to have undergone some shifts from distant metastasis as a rarity to a higher proportion, including disease disseminated via cerebrospinal fluid (CSF) pathway. There is still no report on the pattern of recurrence for Chinese population. Here, we evaluated the pattern of recurrence of GBM in Chinese patients along with factors that could affect the distribution of recurrence. METHODS: Medical records of GBM patients with definite recurrence were reviewed. Local recurrence was defined as tumor regrowth within the preoperative abnormal signals on magnetic resonance imaging (MRI) T2 sequence. New recurrence was a new lesion away from the preoperative T2 abnormalities. New recurrence in contact with CSF pathways was registered as new CSF dissemination. Progress-free survival (PFS) and survival after progress were compared using the Kaplan-Meier survival curves. Potential risk factors for new CSF dissemination were assessed using univariate models followed by multivariate analysis. RESULTS: Thirty-six patients were proven to have recurrence; 22 local and 14 new recurrences. Among the 14 patients, 11 had new CSF dissemination. Median PFS for local, new parenchymal recurrence, and new CSF dissemination were 5.5 months, 9.9 months, and 12.1 months, whereas survival after progress were 6.1 months, 5.7 months, and 16.9 months, respectively. The ventricular entry during surgery and the completion of concomitant chemoradiotherapy were risk factors for new CSF dissemination. O6-methylguanine-DNA methyltransferase methylation was associated with the development of CSF dissemination. CONCLUSION: The majority of recurrence remained local (22/36, 61%). However, CSF dissemination was up to 30% (11/36). PFS for patients with CSF dissemination was the longest, and paradoxically survival after progress was the shortest. Ventricular entry should be avoided. Whole craniospinal MRI surveillance should be included for these patients.

Clinically important difference of Stroke-Specific Quality of Life Scale for aneurysmal subarachnoid hemorrhage.

Health-related quality of life measurements, are commonly used to quantify burden of disease, to evaluate treatment method, and to facilitate benchmarking. The aim of the current study was to determine the Clinically Important Difference (CID) for a Chinese version of Stroke-specific Quality of Life (SS-QOL) in an aneurysmal subarachnoid hemorrhage (SAH) patient cohort. The study recruited SAH patients in a neurosurgical unit in Hong Kong. SAH patients who completed both 3-month and 1-year assessments were included in the analysis. The study received ethical approvals from the joint CUHK-NTEC Clinical Ethics Committee and written informed consent was obtained from all participants or their next of kins. Over a 2-year period, 65 eligible patients were included in the study. Employing the anchor-based approach with global rating of change, the CID estimate of SS-QOL total score was 4.7 (95% confidence interval [CI]: 2.5-5.3), the CID estimate for SSQOL physical subscore was 2.1 (95% CI: 0.3-2.4), and the CID estimate for SS-QOL psychosocial subscore change was 2.8 (95% CI: 1.8-3.7). In conclusion, our study defined the CID for SS-QOL applied to SAH patients and should be further validated in another SAH patient population.

Subthalamic Nucleus Deep Brain Stimulation for Parkinson Disease in Hong Kong: A Prospective Territory-Wide 2-Year Follow-Up Study.

OBJECTIVE: We assessed the effects of bilateral subthalamic nucleus (STN) deep brain stimulation (DBS) in patients with Parkinson disease at the 1-year and 2-year follow-up evaluations. Unified Parkinson's Disease Rating Scale (UPDRS) motor score at "off" medication ("on" DBS) and quality-of-life assessments (39-item Parkinson's Disease Questionnaire [PDQ-39]) were conducted. The percentage of awake "on" time and awake "off" time and levodopa requirement were also assessed. METHODS: A 2-year prospective study was conducted of 25 consecutive patients from 3 DBS referral centers in Hong Kong. The patients were treated with bilateral stimulation of the STN. Assessments were performed at 1 year and 2 years after DBS and were compared with the baseline. RESULTS: The 2-year outcome assessments were completed by 18 patients. The mean UPDRS motor score improvement was 57% in the first year and 45% in the second year. PDQ-39 showed significant improvement in quality of life for 2 consecutive years. The levodopa requirement decreased 63% in the first year and 55.9% in the second year. The awake "on" time was doubled in the first year and sustained in the second year. Awake "off" time was reduced from 28.1% to 5.9% in the first year and returned to 10.6% in the second year. Improvement of UPDRS motor score, reduction in awake "off" time, and decrease of daily levodopa dosage all were main factors correlated with the improvement in PDQ-39 summary index. CONCLUSIONS: The effects of STN DBS in patients with Parkinson disease in Hong Kong were satisfactory. The results showed that reduction in UPDRS motor score, awake "off"-time, and daily levodopa dosage were the major drivers of overall improvement in PDQ-39.

Screening for intracranial aneurysms? Prevalence of unruptured intracranial aneurysms in Hong Kong Chinese.

OBJECT The objective of this study was to generate data on the local prevalence of unruptured intracranial aneurysms (UIAs) in asymptomatic Hong Kong Chinese individuals. First-degree relatives of patients with aneurysmal subarachnoid hemorrhage (aSAH) were recruited as surrogates of the general population and to explore the potential role of screening in this locality. METHODS The authors identified first-degree relatives of consecutive patients with subarachnoid hemorrhage from a ruptured aneurysm who were admitted to a university hospital in Hong Kong from June 2008 to December 2010. Magnetic resonance angiography (MRA) was the imaging modality used to screen the cerebral vasculature of these asymptomatic individuals. If MRA showed abnormal findings, CT angiography was performed to confirm the MRA findings. RESULTS In total, 7 UIAs were identified from the 305 MR angiograms obtained. The prevalence of UIAs in first-degree relatives of patients with aSAH in the Hong Kong Chinese population was 2.30% (95% CI1.02%-4.76%). This percentage was lower than the prevalence rate of 3.2% from a meta-analysis of the literature. The sizes of the UIAs detected ranged from 1.4 mm to 7.5 mm; 85.7% of the UIAs detected in this study were < 5 mm, in contrast to 66% noted in the literature. One of the UIAs identified underwent endovascular stent placement with a flow diverter. None of the UIAs identified ruptured or became symptomatic during a median follow-up period of 3.5 years. CONCLUSIONS The prevalence of UIAs in first-degree relatives of patients with aSAH in the Hong Kong Chinese population was lower than that in Caucasians. At the same time, most of the UIAs detected in this study were small (85.7% were < 5 mm, vs 66% in a meta-analysis). With a similar incidence of aSAH in Hong Kong (7.5 per 100,000 person-years) as compared with data cited in the literature, the hypothesis that UIA rupture risk size threshold is different in Chinese patients should be further investigated.

Early Magnesium Treatment After Aneurysmal Subarachnoid Hemorrhage: Individual Patient Data Meta-Analysis.

BACKGROUND AND PURPOSE: Delayed cerebral ischemia (DCI) is an important cause of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). Trials of magnesium treatment starting <4 days after symptom onset found no effect on poor outcome or DCI in SAH. Earlier installment of treatment might be more effective, but individual trials had not enough power for such a subanalysis. We performed an individual patient data meta-analysis to study whether magnesium is effective when given within different time frames within 24 hours after the SAH. METHODS: Patients were divided into categories according to the delay between symptom onset and start of the study medication: <6, 6 to 12, 12 to 24, and >24 hours. We calculated adjusted risk ratios with corresponding 95% confidence intervals for magnesium versus placebo treatment for poor outcome and DCI. RESULTS: We included 5 trials totaling 1981 patients; 83 patients started treatment<6 hours. For poor outcome, the adjusted risk ratios of magnesium treatment for start <6 hours were 1.44 (95% confidence interval, 0.83-2.51); for 6 to 12 hours 1.03 (0.65-1.63), for 12 to 24 hours 0.84 (0.65-1.09), and for >24 hours 1.06 (0.87-1.31), and for DCI, <6 hours 1.76 (0.68-4.58), for 6 to 12 hours 2.09 (0.99-4.39), for 12 to 24 hours 0.80 (0.56-1.16), and for >24 hours 1.08 (0.88-1.32). CONCLUSIONS: This meta-analysis suggests no beneficial effect of magnesium treatment on poor outcome or DCI when started early after SAH onset. Although the number of patients was small and a beneficial effect cannot be definitively excluded, we found no justification for a new trial with early magnesium treatment after SAH.

Mindfulness-based therapy for drug-resistant epilepsy: An assessor-blinded randomized trial.

OBJECTIVE: To investigate the effectiveness of mindfulness-based therapy (MT) and social support (SS) in patients with drug-resistant epilepsy. METHODS: We performed an assessor-blinded randomized control trial. Sixty patients with drug-resistant epilepsy were randomly allocated to MT or SS (30 per group). Each group received 4 biweekly intervention sessions. The primary outcome was the change in the total score of the Patient-Weighted Quality of Life in Epilepsy Inventory (QOLIE-31-P). Secondary outcomes included seizure frequency, mood symptoms, and neurocognitive functions. The assessors were blinded to the patient's intervention grouping. Results were analyzed using general linear model with repeated measure. RESULTS: Following intervention, both the MT (n=30) and SS (n=30) groups had an improved total QOLIE-31-P, with an improvement of +6.23 for MT (95% confidence interval [CI] +4.22 to +10.40) and +3.30 for SS (95% CI +1.03 to +5.58). Significantly more patients in the MT group had a clinically important improvement in QOLIE-31-P (+11.8 or above) compared to those who received SS (11 patients vs 4 patients). Significantly greater reduction in depressive and anxiety symptoms, seizure frequency, and improvement in delayed memory was observed in the MT group compared with the SS group. CONCLUSIONS: We found benefits of short-term psychotherapy on patients with drug-resistant epilepsy. Mindfulness therapy was associated with greater benefits than SS alone in quality of life, mood, seizure frequency, and verbal memory. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that mindfulness-based therapy significantly improves quality of life in patients with drug-resistant epilepsy.

Cognitive outcome in acute simvastatin treatment for aneurysmal subarachnoid hemorrhage: A propensity matched analysis.

OBJECTIVES: Experimental evidence has indicated the benefit of simvastatin in the treatment of subarachnoid hemorrhage (SAH). Recently, acute simvastatin treatment was not shown to be beneficial in neurological outcome using modified Rankin Scale. Cognitive function is another important dimension of outcome assessment and yet had not been investigated in statin studies for aneurysmal subarachnoid hemorrhage. We therefore explored whether acute simvastatin treatment would improve cognitive outcomes. METHODS: The study recruited SAH patients with acute simvastatin treatment enrolled in a randomized controlled double-blinded clinical trial (ClinicalTrials.gov Identifier: NCT01038193). A control cohort of SAH patients without simvastatin treatment was identified with propensity score matching of age and admission grade. Primary outcome measure was Montreal Cognitive Assessment (MoCA). Secondary outcome measures were delayed ischaemic deficit (DID), delayed cerebral infarction, modified Rankin Scale (mRS), and Mini-Mental State Examination (MMSE). RESULTS: Fifty-one SAH patients with acute simvastatin treatment and 51 SAH patients without simvastatin treatment were recruited for analysis. At 3 months, there were no differences in MoCA scores (MoCA: 21+/-6 vs. 21+/-5, p=0.772). MoCA-assessed cognitive impairment (MoCA<26) was not different (75% vs. 80%, OR 0.7, 95%CI 0.3 to 1.8, p=0.477). There were also no differences in DID, delayed cerebral infarction, favorable mRS outcome, and MMSE scores, and MMSE-assessed cognitive impairment between both groups. CONCLUSIONS: The current study does not support that acute simvastatin treatment improves cognitive outcome after aneurysmal subarachnoid hemorrhage.

Ictal high-frequency oscillations and hyperexcitability in refractory epilepsy.

OBJECTIVE: High-frequency oscillations (HFOs, 80-500Hz) from intracranial electroencephalography (EEG) may represent a biomarker of epileptogenicity for epilepsy. We explored the relationship between ictal HFOs and hyperexcitability with a view to improving surgical outcome. METHODS: We evaluated 262 patients with refractory epilepsy. Fifteen patients underwent electrode implantation, and surgical resection was performed in 12 patients using a semi-prospective design. Ictal intracranial EEGs were examined by continuous wavelet transform (CWT). Significant ictal HFOs were denoted by normalized wavelet power above the 50th percentile across all channels. Each patient underwent functional mapping with cortical electrical stimulation. Hyperexcitability was defined as the appearance of afterdischarges or clinical seizures after electrical stimulation (50Hz, biphasic, pulse width=0.5ms, 5s, 5mA). RESULTS: Among the group of patients achieving Engel Class I/II outcome at 1+ year, the mean proportion of significant ictal HFOs among resected channels for any given patient was 69% (33.3-100%). The respective figures for conventional frequency ictal patterns (CFIPs), hyperexcitability, and radiological lesion were 68.3% (26.3-100%), 39.6% (0-100%), and 52.8% (0-100%). Statistical significance was only achieved with ictal HFOs when comparing patients with Engel Class I/II outcomes versus III/IV outcomes (12.6% vs. 4.2%, the number of channels as the denominator, p=0.005). Further analysis from all patients irrespective of the surgical outcome showed that ictal HFOs co-occurred with CFIP (p<0.001), hyperexcitability (p<0.001), and radiological lesion (p<0.001). The combination of ictal HFOs/hyperexcitability improved the sensitivity from 66.7% to 100%, and the specificity from 66.7% to 75% when compared with ictal HFOs or hyperexcitability alone. CONCLUSIONS: We confirmed the utility of ictal HFOs in determining surgical outcome. Ictal HFOs are affiliated to cortical hyperexcitability, which may represent a pathological manifestation of epileptogenicity. SIGNIFICANCE: Presurgical evaluation of refractory epilepsy may incorporate both ictal HFOs and cortical stimulation in determining epileptogenic foci.

High-dose simvastatin for aneurysmal subarachnoid hemorrhage: multicenter randomized controlled double-blinded clinical trial.

BACKGROUND AND PURPOSE: Experimental evidence has indicated the benefits of simvastatin for the treatment of subarachnoid hemorrhage. Two randomized placebo-controlled pilot trials that used the highest clinically approved dose of simvastatin (80 mg daily) gave positive results despite the fact that a lower dose of simvastatin (40 mg daily) did not improve clinical outcomes. We hypothesized that a high dose of 80 mg of simvastatin daily for 3 weeks would reduce the incidence of delayed ischemic deficits after subarachnoid hemorrhage compared with a lower dose (40 mg of simvastatin daily) and lead to improved clinical outcomes. METHODS: The study design was a randomized controlled double-blinded clinical trial. Patients with aneurysmal subarachnoid hemorrhage (presenting within 96 hours of the ictus) from 6 neurosurgical centers were recruited for 3 years. The primary outcome measure was the presence of delayed ischemic deficits, and secondary outcome measures included a modified Rankin disability score at 3 months and an analysis of cost-effectiveness. RESULTS: No difference was observed between the groups treated with the higher dose or the lower dose of simvastatin in the incidence of delayed ischemic deficits (27% versus 24%; odds ratio, 1.2; 95% confidence interval, 0.7-2.0; P=0.586) or in the rate of favorable outcomes (modified Rankin Scale score, 0-2) at 3 months (73% versus 72%; odds ratio, 1.1; 95% confidence interval, 0.6-1.9; P=0.770). CONCLUSIONS: High-dose simvastatin treatment should not be prescribed routinely for aneurysmal subarachnoid hemorrhage. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01077206.

Cost-effectiveness of subthalmic nucleus deep brain stimulation for the treatment of advanced Parkinson disease in Hong Kong: a prospective study.

BACKGROUND: Deep brain stimulation (DBS) is an effective but costly treatment for patients with advanced Parkinson disease (PD). This study examined the cost-effectiveness of DBS in relation to its improved effectiveness to help funding decision makers decide whether the treatment should be adopted. The incremental cost-effective ratio (ICER) per quality-adjusted life year has been benchmarked as being between US$50,000 and US$100,000 by US agencies, whereas it is less than €30,000 per quality-adjusted life year in Europe. OBJECTIVE: To provide cost-effectiveness information of subthalamic nucleus DBS for patients with advanced PD. MATERIALS: Direct medical expenses during the year before the DBS treatment were used to measure the baseline cost. Cost-effectiveness was measured by the ICER for the Unified Parkinson's Disease Rating Scale Part III and the ICER for the EuroQol Group's Health-Related Quality of Life measurement. RESULTS: Thirteen patients with advanced PD were recruited between January 2009 and January 2011. A 1-point improvement in the Unified Parkinson's Disease Rating Scale Part III score was associated with an ICER of US$926 in the first year and US$421 in the second year. A 1-point improvement on the EuroQol Group's Health-Related Quality of Life measurement was associated with an ICER of US$123,110 in the first year and US$62,846 in the second year. CONCLUSION: Cost-effectiveness of subthalamic nucleus DBS for treatment of advanced PD is greater during a 2-year period than 1 year only. These results can be used as a reference for the use of DBS for PD in a region with public health financing.

A comparison of functional outcome in patients sustaining major trauma: a multicentre, prospective, international study.

OBJECTIVES: To compare 6 month and 12 month health status and functional outcomes between regional major trauma registries in Hong Kong and Victoria, Australia. SUMMARY BACKGROUND DATA: Multicentres from trauma registries in Hong Kong and the Victorian State Trauma Registry (VSTR). METHODS: Multicentre, prospective cohort study. Major trauma patients and aged ≥18 years were included. The main outcome measures were Extended Glasgow Outcome Scale (GOSE) functional outcome and risk-adjusted Short-Form 12 (SF-12) health status at 6 and 12 months after injury. RESULTS: 261 cases from Hong Kong and 1955 cases from VSTR were included. Adjusting for age, sex, ISS, comorbid status, injury mechanism and GCS group, the odds of a better functional outcome for Hong Kong patients relative to Victorian patients at six months was 0.88 (95% CI: 0.66, 1.17), and at 12 months was 0.83 (95% CI: 0.60, 1.12). Adjusting for age, gender, ISS, GCS, injury mechanism and comorbid status, Hong Kong patients demonstrated comparable mean PCS-12 scores at 6-months (adjusted mean difference: 1.2, 95% CI: -1.2, 3.6) and 12-months (adjusted mean difference: -0.4, 95% CI: -3.2, 2.4) compared to Victorian patients. Keeping age, gender, ISS, GCS, injury mechanism and comorbid status, there was no difference in the MCS-12 scores of Hong Kong patients compared to Victorian patients at 6-months (adjusted mean difference: 0.4, 95% CI: -2.1, 2.8) or 12-months (adjusted mean difference: 1.8, 95% CI: -0.8, 4.5). CONCLUSION: The unadjusted analyses showed better outcomes for Victorian cases compared to Hong Kong but after adjusting for key confounders, there was no difference in 6-month or 12-month functional outcomes between the jurisdictions.

Characteristics of rat lumbar vertebral body bone mineral density and differential segmental responses to sex hormone deficiency: a clinical multidetector computed tomography study.

OBJECTIVE: To investigate sex hormone deficiency related osteoporosis and efficacy of different therapies. METHODS: Orchiectomized and ovariectomized rat models are used to investigate sex hormone deficiency related osteoporosis and efficacy of different therapies. A rat vertebral body can be longitudinally divided into central portion, which contain more trabecular bone, and para-endplate portions which contain more compact bone. In matured male and female Wistar and Sprague-Dawley rat lumbar spines, we investigated baseline bone mineral density (BMD) characteristics and the differential segmental responses in bone loss within the lumbar vertebral body post gonadal surgery with clinical multidetector computed tomography. RESULTS: Para-endplate sections had a higher BMD than central sections. The cephalad para-endplate sections had a higher BMD than the caudad para-endplate sections. Eight weeks after gonadal removal, there was more bone loss in central sections than para-endplate sections. The relative difference of bone loss between para-endplate and central sections was more apparent in male rats than in female rats. There was more bone loss in caudad sections than cephalad sections; this lead to a further increase of BMD difference between caudad para-endplate sections and cephalad para-endplate sections post gonadal surgery. CONCLUSION: The approach described in this study provided a consistent way to study BMD change within predominantly compact bone portion and trabecular bone portion of the vertebral body.

Validation of the modified radiosurgery-based arteriovenous malformation score in a linear accelerator radiosurgery experience in Hong Kong.

The modified radiosurgery-based arteriovenous malformation (AVM) score (modified AVM score or Pollock-Flickinger AVM score [PFAS]) is a simplified grading system developed to predict outcome after gamma knife radiosurgery for cerebral AVM. The purpose of this study was to test the PFAS in a cohort of patients managed with linear accelerator (LINAC) radiosurgery. We analyzed 70 consecutive patients with cerebral AVM treated with LINAC radiosurgery in Hong Kong. The scores were determined by the following equation: Modified AVM score=(0.1×volume [cm(3)])+(0.02×age [years])+(0.5×location). The location values are as follows: hemispheric/corpus callosum/cerebellar=0; basal ganglia/thalamus/brainstem=1. A total of 74% of patients presented with ruptured AVM before radiosurgery. The overall obliteration rate was 86%. Five (7%) patients developed new permanent neurological deficits from delayed bleeding or radiation-induced complications. Modified AVM score correlated with the percentage of patients with AVM obliteration without new neurological deficits (≤1, 96%; 1.01-1.50, 78%; 1.51-2.00, 90%; >2, 50%; Spearman's rho 0.354, p=0.003). In conclusion, the modified AVM score is a good predictor of patient outcome after LINAC radiosurgery in our cohort. The modified AVM score can be used to guide treatment selection for cerebral AVM and stratify patients for future comparative analyses.

Effect of ovariectomy on contrast agent diffusion into lumbar intervertebral disc: a dynamic contrast-enhanced MRI study in female rats.

PURPOSE: The purpose was to study the effect of estrogen deficiency on contrast agent diffusion into intervertebral disc in a rat model. MATERIALS AND METHODS: Seven-month-old female Sprague-Dawley rats were used. Fourteen rats had ovariectomy, and nine rats had sham surgery. Magnetic resonance imaging (MRI) of sagittal midsection of lumbar spine was performed with a 1.5-T magnet. Dynamic MRI was performed after a bolus injection of Gd-DOTA (0.3 mmol/kg) through tail vein. Eight hundred images were acquired at 0.6 s per acquisition. Regions of interests were drawn over three discs per rat. Maximum enhancement (E(max)) and enhancement slope (E(slope)) were evaluated. MRI was carried out at baseline and 8 weeks postsurgery. RESULT: All disc enhancements demonstrated an initial fast wash-in phase followed by a second slower wash-in phase. For initial wash-in phase, E(1)(max) and E(1)(slope) of all rats remained unchanged at the two time points. For second wash-in phase, E(2)(max) and E(2)(slope) of control rats remained unchanged, while with ovariectomized rats, E(2)(max) showed reduction at 8 weeks (4.5%±5.6%) compared to baseline (10.3%±6.3%, P=.037), and E(2)(slope) was lower at 8 weeks (0.015±0.017) than the baseline (0.029±0.022), although it was not statistically significant (P=.101). CONCLUSION: Ovariectomy induced detectable decrease in second wash-in phase of contrast agent into lumbar disc.