Impaired cerebrovascular reactivity is associated with recurrent stroke in patients with severe intracranial arterial stenosis: A C02 BOLD fMRI study

Background and PurposeSevere intracranial atherosclerotic stenosis (SIAS) remains at risk of recurrent ischemic events despite intensive medical management. Exhausted cerebrovascular reserve seems to be associated with higher risk of recurrent stroke.Materials and MethodsWe used whole brain MRI to estimate basal perfusion using dynamic susceptibility contrast and cerebrovascular reactivity (CVR) to hypercapnic challenge (CO2 inhalation) using BOLD contrast, in 20 patients with symptomatic SIAS (> 70%) of the middle cerebral artery (MCA) or the distal internal carotid artery. We studied relationships between individual clinical, biological, radiological baseline characteristics, recurrent ischemic events, basal perfusion parameters (mean transit time, delay, time to peak, cerebral blood flow and volume), and CVR measured in MCA territories (CVRMCA), and reported using laterality indices (LI).ResultsTen patients had an impaired CVR with (|LI| CVRMCA ≥ 0.08). During a mean follow-up of 3.3 years, all recurrent ipsilateral ischemic events occurred within the first year. They were more frequent in impaired CVRMCA group (n = 7/10 patients) than in normal CVRMCA group (n = 1/10), with different survival curves (log rank, P = 0.007).ConclusionImpaired CVR is associated with an increased rate of recurrent stroke in patients with symptomatic SIAS. CVR mapping should be used as a well tolerated method to select higher-risk patients in further therapeutic trials such as endovascular procedures.     

Superficial temporal artery–middle cerebral artery bypass for ischemic atherosclerotic middle cerebral artery disease

Most recent studies on the effectiveness of cerebral revascularization have focused on the treatment of atherosclerotic internal carotid artery occlusive disease. The goal of the present study was to assess neurological function in 11 severe atherosclerotic middle cerebral artery (MCA) disease patients with transient ischemic attacks (TIAs) and hemodynamic compromise and determine the efficacy of superficial temporal artery–middle cerebral artery (STA-MCA) bypass. There were eight patients with MCA occlusion and three with severe MCA stenosis. After the bypass procedure, all 11 patients experienced reduction in TIAs and no stroke during a mean follow-up of 34.36 months. Surgical revascularization increased regional cerebral blood flow (mL/100 g/min) from a mean of (± standard deviation) 25.9 ± 7.39 preoperatively to 32.3 ± 7.72 postoperatively, and improved regional cerebrovascular reactivity from ?6.42% ± 14.61% to 30.14% ± 23.93% (p = 0.014) in the eight patients with atherosclerotic MCA occlusion. Our findings demonstrated the benefit of STA-MCA bypass for patients with medically refractory and symptomatic atherosclerotic MCA occlusion with hemodynamic compromise.     

Objective evaluation of cerebrovascular reactivity for acetazolamide predicts cerebral hyperperfusion after carotid artery stenting: Comparison with region of interest methods

Background and purpose

Hemodynamic impairments are considered risk factors of cerebral hyperperfusion after carotid artery stenting (CAS); measurement by Single-photon emission computed tomography (SPECT) using a subjective region of interest (ROI) method lacks consistency and reproducibility.

Detection of impaired cerebrovascular reactivity in patients with chronic cerebral ischemia using whole-brain 7T MRA

BackgroundCerebrovascular reactivity (CVR) to acetazolamide (ACZ) on single-photon emission computed tomography (SPECT) can be used to assess the severity of chronic cerebral ischemia; however, this is an invasive method. We examined whether whole-brain magnetic resonance angiography (MRA) at 7T could non-invasively detect impaired CVR in patients with chronic cerebral ischemia by demonstrating the leptomeningeal collaterals (LMCs).MethodsFifty-seven patients with symptomatic unilateral cervical stenosis underwent whole-brain time-of-flight MRA at 7T and cerebral perfusion SPECT before/after the ACZ challenge. MRA images were visually assessed based on 6-point grading systems to evaluate the development of LMCs toward the middle cerebral artery (MCA) and antegrade flow of MCA. CVR of the affected side was calculated from the SPECT data. Subsequently, we compared the LMC grades on MRA with CVR on SPECT.ResultsCVR was significantly lower in grades ≥ 2 of LMCs than in grades 0–1 (P < 0.05) when applying LMCs from the anterior cerebral artery (ACA) and/or posterior cerebral artery (PCA). These differences were more evident than those in the grading of the antegrade MCA flow. The LMC grades from ACA/PCA readily detected reduced CVR (< 18.4%) with a sensitivity/specificity of 0.79/0.82.ConclusionThe development of LMCs on whole-brain MRA at 7T can non-invasively detect reduced CVR with a high sensitivity/specificity in patients with unilateral cervical stenosis.     

A single-center study of Wingspan stents for symptomatic atherosclerotic stenosis of the middle cerebral artery

The middle cerebral artery (MCA) is one of the most common sites of symptomatic intracranial atherosclerosis. We assessed the safety and efficacy of the Wingspan stent (Boston Scientific, Natick, MA, USA) for the treatment of symptomatic atherosclerotic MCA stenosis. Sixty-one patients with symptomatic MCA stenosis with narrowing of at least 70% among 61 patients were treated using Wingspan stents from March 2007 to December 2010. Clinical outcomes and imaging features were recorded and analyzed. The technical success rate was 98.4%. The rate of procedure-related complications during the periprocedural period (30 days) was 5.0% (three of 61 patients), which included one ischemic complication and two hemorrhagic complications with no permanent neurological sequelae. The mean degree of stenosis decreased from 76.8 ± 6.0% to 12.0 ± 11.5% following treatment. Forty-five patients (74%) were available for follow-up imaging with digital subtraction arteriography. In-stent restenosis (ISR) was documented in seven of these patients. A total of 61 patients were available for a clinical follow up. Four ischemic events (6.6%) occurred during the follow-up period, which were all transient ischemic attacks including two symptomatic ISR. The cumulative probability of an adverse event was 11.7% at 1 year. Of the 61 patients, 51 (83.6%) had their follow-up visit more than 12 months after the procedure, and no adverse events were found beyond 12 months after the procedure. Percutaneous transluminal angioplasty and stenting of the MCA was safe and associated with a low periprocedural complication rate. It may result in a good long-term benefit. Prospective randomized controlled trials and further long-term follow up are needed to provide more adequate statistical evidence to support our findings.     

Pre- and Post-Angioplasty Perfusion CT with Acetazolamide Challenge in Patients with Unilateral Cerebrovascular Stenotic Disease

Objective

Perfusion computed tomography (PCT) has the ability to measure quantitative value and produce maps of mean transit time (MTT), cerebral blood flow (CBF), and cerebral blood volume (CBV). We assessed cerebral hemodynamics by using these parameters and acetazolamide (ACZ) challenge for pre- and post-procedural evaluation in patients with unilateral cerebrovascular stenotic disease.

Methods

Thirty patients underwent pre-procedural PCT with ACZ challenge, and 24 patients (80%) was conducted follow up PCT after angioplasty with same protocol. The mean MTT, CBF, and CBV were measured and compared in both middle cerebral arterial (MCA) territories before and after ACZ challenge. Hemispheric ratio and percent change after ACZ challenge were calculated before and after angioplasty.

Results

The mean stenosis rate was 76.6%. Significant increases in MTT (32.6%, p=0.000) and significant decreases in CBF (-14.2%, p=0.000) were found in stenotic side MCA territories. After ACZ challenge, there were significant changes in MTT (37.4%, p=0.000), CBF (-13.1%, p=0.000), and CBV (-10.5%, p=0.001) in pre-procedural perfusion study. However, no significant increases were found in MTT, or decreases in CBF and CBV in post-procedural study. There were no significant changes after ACZ challenge also. In addition, the degrees of these changes (before and after ACZ challenge) were highly correlated with the stenotic degrees in pre-procedural perfusion study.

Conclusion

PCT with ACZ challenge appears to be a useful tool to assess the cerebral perfusion status especially in patients with unilateral symptomatic stenotic disease.     

Reduced middle cerebral artery velocity during cross-clamp predicts cognitive dysfunction after carotid endarterectomy

Transcranial Doppler (TCD) is a useful monitor that can be utilized during carotid endarterectomy (CEA). Cognitive dysfunction is a subtler and more common form of neurologic injury than stroke. We aimed to determine whether reduced middle cerebral artery (MCA) mean velocity (MV) predicts cognitive dysfunction and if so, whether a threshold of increased risk of cognitive dysfunction can be identified. One hundred twenty-four CEA patients were included in this observational study and neuropsychometrically evaluated preoperatively and 24 hours postoperatively. MCA–MV was measured by TCD and percentage of baseline during cross-clamp was calculated (MV_cross-clamp/MV_baseline). Patients with cognitive dysfunction had significantly lower MV during cross-clamp than those without cognitive dysfunction (33.1 ± 13.7 cm/s versus 39.6 ± 16.0 cm/s, p = 0.02). In the final multivariate model, each percent reduction in MV was significantly associated with greater risk of cognitive dysfunction (odds ratio [OR]: 0.05 [95% confidence interval {CI} 0.01–0.23], p < 0.001) while statin use was associated with lower risk (OR: 0.33 [95% CI 0.12–0.92], p = 0.03). Using receiver operator characteristic curve analysis, the Youden index identified 72% of baseline MV during cross-clamp as the cutoff of maximum discrimination. Significantly more patients with MV < 72% of baseline during cross-clamp exhibited cognitive dysfunction than patients with MV ⩾ 72% of baseline (74.1% versus 27.1%, p < 0.001). Reduced MCA–MV during cross-clamp is a predictor of cognitive dysfunction exhibited 24 hours after CEA. MCA–MV reduced to <72% of baseline, or a ⩾28% reduction from baseline, is the threshold most strongly associated with increased risk of cognitive dysfunction. These observations should be considered by all clinicians that utilize intraoperative monitoring for CEA.     

Cerebral arteriostenosis associated with elevated serum-immunoglobulin E level in young adults without risk factors for ischemic stroke: A possible manifestation of cerebral vasculitis?

We report a series of young adults with symptomatic cerebral arteriostenosis characterized by elevated serum immunoglobulin (Ig) E levels. All patients had no definite risk factors for cerebral vascular diseases. The clinical data of 26 young adults (age 18–50 years) with ischemic stroke, characterized only by increased serum IgE levels and without risk factors for cerebral vascular disease, were retrospectively reviewed. Arteriostenosis was surveyed and followed-up by digital subtraction angiography (DSA), and the stenosis rate was estimated using the warfarin–aspirin symptomatic intracranial disease technique. All patients were treated with corticosteroids according to the common strategy for vasculitis. There was no recurrent stroke during follow-up. The mean degree of stenosis before and after treatment was 69.3 ± 29.8% and 47.9 ± 45.1%, respectively. The difference of stenosis rates between initial and follow-up DSA evaluation was significant using a paired samples test (21.31 ± 26.88, 95% confidence interval [CI] 13.58–29.03, t = 5.55, p < 0.001). Kaplan–Meier survival analysis revealed that the 13-month cumulative improved lesion rate was 40.3 ± 8.7%. This remained the same at 18 months. The mean time to lesion improvement was 12.58 ± 0.96 months (95% CI 10.70–14.46) and median time was 13 ± 3.88 months (95% CI 5.39–20.61). To our knowledge, cerebral arteriostenosis with only elevated IgE serum levels has not been reported. Our data showed that corticosteroid treatment can achieve clinical and artery improvement. This suggests that the cerebral arteriostenosis seen in our study might be caused by some specific type of vessel inflammation.     

Periprocedural MRI perfusion imaging to assess and monitor the hemodynamic impact of intracranial angioplasty and stenting for symptomatic atherosclerotic stenosis

We aimed to assess the clinical value of MRI perfusion imaging in the periprocedural management of intracranial atherosclerosis, analyzing if changes in mean transit time (MTT), cerebral blood volume (CBV) and cerebral blood flow (CBF) correlated with angiographic outcomes. Pre-procedural and post-procedural MRI perfusion was performed on six patients who underwent angioplasty and/or stenting for symptomatic intracranial atherosclerosis. MTT, CBV and CBF were analyzed and graded. In 83% of patients, perfusion imaging correlated with angiographic outcomes. Perfusion parameters improved to normal in two patients. Two showed marked improvement and one showed mild improvement. In one patient, the results of the post-procedural MRI perfusion prompted an angiogram, which confirmed stent occlusion. Semi-quantitative scores of MTT and CBF changed over time (p = 0.05, p = 0.03) whereas CBV did not change significantly (p > 0.05). We conclude that MRI perfusion appears a promising technique for analyzing the impact of intracranial stenosis on cerebral hemodynamics before and after treatment.     

What influenced the lesion patterns and hemodynamic characteristics in patients with internal carotid artery stenosis? A retrospective study

Objectives

This study aimed to explore the dynamic changes of lesion patterns and hemodynamic characteristics in patients with internal carotid artery stenosis (ICAS).

Assessment of cerebrovascular reserve in unilateral middle cerebral artery stenosis using perfusion CT and CO2 inhalation tests

Purpose/Aim of the study: Cerebrovascular reactivity (CVR) is an important marker for assessing cerebrovascular disease. This study assessed the CVR by perfusion computed tomography (CT) and CO₂ inhalation tests in patients with unilateral middle cerebral artery (MCA) stenosis disease. Materials and Methods: Thirty-one patients with unilateral MCA stenosis disease diagnosed by digital subtraction angiography were studied. Patients were divided into two groups according to the degree of stenosis: severe and moderate. The regional cerebral blood flow (CBF) before and after CO₂ inhalation was determined by perfusion CT. Regional CVR values were obtained by the following formula: increase (%) = (post-CBF) ? (pre-CBF)/(pre-CBF) × 100%. Results: No significant differences in the mean CBF in the MCA stenosis region were found between the affected and contralateral sides before the CO₂ inhalation test; after the test, CBF was more significantly decreased on the affected side than on the contralateral side. The changes in CBF on the affected side were categorized into three types: increased CBF (17 cases), decreased CBF (12 cases) and no change in CBF (2 cases). The rate of CVR impairment among severe stenosis patients (13/19) was higher than that among moderate stenosis patients (3/12). CVR was significantly correlated with the degree of stenosis (r = 0.423, P = 0.018). Conclusion: CVR impairment was found in approximately half of patients with unilateral MCA stenosis. Along with an increase in the degree of stenosis, patients with unilateral MCA stenosis were more likely to exhibit CVR impairment. It is important to assess the CVR in patients with unilateral MCA stenosis, especially those with severe stenosis.     

Perfusion CT investigation of chronic internal carotid artery occlusion: comparison with SPECT

This study investigated the usefulness of perfusion computed tomography (CT) for the evaluation of patients with chronic internal carotid artery (ICA) occlusion by comparing the findings with those of iodine-123 iodoamphetamine ([¹²³I]IMP) single photon emission computed tomography (SPECT). Twenty five patients with chronic ICA occlusion were investigated on the same day by perfusion CT to measure the cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transient time (MTT), and [¹²³I]IMP SPECT to measure the regional CBF, significant correlations were observed between regional CBF measured by SPECT and CBF measured by perfusion CT (r = 0.659, R² = 0.434, p < 0.001), regional CBF and CBV (r = −0.406, R² = 0.165, p < 0.001) and regional CBF and MTT (r = −0.592, R² = 0.350, p < 0.001). Significant correlations were also observed between CBF and CBV (r = −0.153, R² = 0.023, p < 0.001), CBF and MTT (r = −0.580, R² = 0.337, p < 0.001) and MTT and CBV (r = 0.763, R² = 0.582, p < 0.001). Perfusion CT is useful to evaluate the hemodynamic state of patients with chronic major cerebral artery occlusive disorders.     

Excellent rates of recanalization and good functional outcome after stent-based thrombectomy for acute middle cerebral artery occlusion. Is it time for a paradigm shift?

The natural history of untreated acute middle cerebral artery (MCA) occlusion is poor, with high rates of mortality (5–33%) and severe long-term disability (40–80% of survivors), despite therapy with intravenous tissue plasminogen activator. We analyzed outcomes in 31 consecutive patients with major ischemic stroke due to acute proximal MCA occlusion who were treated at the Hadassah-Hebrew University Medical Center from February 2010 to October 2012 by endovascular means, using the Solitaire stent (Covidien, Irvine, CA, USA) as a thrombectomy device. Patients had a mean age of 63.3 ± 16.2 years (range, 26–92). The admission National Institutes of Health Stroke Scale score was 19.5 ± 4.3 (median 20). Mean time from symptom onset to femoral artery puncture was 3.8 ± 1.1 hours (median 4 hours). Mean time to recanalization was 46.9 ± 11.1 minutes. Successful recanalization by means of stent-based thrombectomy alone was achieved in 90% of cases and reached 100% after combining definitive stent implantation in three patients. There was no arterial rupture or subarachnoid hemorrhage. Hemorrhagic transformation developed in seven patients (23%), but was symptomatic in only one. Post-procedure CT scan or MRI demonstrated >90% sparing of cortex at risk in all patients. Functional outcome at 90 day follow-up was modified Rankin Score 0–2 in 77% of all patients and 88% of patients younger than 80 years. Three patients (10%) died during hospitalization due to mesenteric event, sepsis, or pulmonary embolism. Our experience suggests that stent-based thrombectomy in selected patients for acute MCA occlusions is safe, very effective in terms of arterial recanalization, and associated with improved neurological outcome. If validated by other groups, endovascular treatment may be proposed as the therapy of choice for MCA occlusion.     

An anatomical analysis of the mini-modified orbitozygomatic and supra-orbital approaches

Seven sides of cadaver heads were used to compare the surgical exposures provided by the mini-modified orbitozygomatic (MOz) and supra-orbital (SO) approaches. The Optotrak 3020 computerized tracking system (Northern Digital, Waterloo, ON, Canada) was utilized to evaluate the area of anatomical exposure defined by six points: (1) ipsilateral sphenoid ridge; (2) most distal point of the ipsilateral middle cerebral artery (MCA); (3) most distal point of the ipsilateral posterior cerebral artery (PCA); (4) most distal point of the contralateral PCA; (5) most distal point of the contralateral MCA; and (6) contralateral sphenoid ridge. Additionally, angles of approach for the ipsilateral MCA bifurcation, ipsilateral ICA bifurcation, basilar artery tip, contralateral MCA and ICA bifurcation and anterior communicating artery (AcomA) were evaluated, first for SO and then for MOz. An image guidance system was used to evaluate the limits of surgical exposure. No differences in the area of surgical exposure were noted (p > 0.05). Vertical angles were significantly wider for the ipsilateral and contralateral ICA bifurcation, AcomA, contralateral MCA and basilar tip (p < 0.05) for MOz. No differences in horizontal angles were observed between the approaches for the six targets (p > 0.05). There were no differences in the limits of exposure. MOz affords no additional surgical working space. However, our results demonstrate systematically that vertical exposure is improved. The MOz should be performed while planning an approach to these regions and a wider exposure in the vertical axis is needed.     

Causes and outcomes of new onset status epilepticus and predictors of refractoriness to therapy

We aimed to evaluate the determinants of outcome in new onset refractory status epilepticus (SE). A retrospective analysis of patients with new onset SE admitted between May 2005 and October 2013 was performed. Regression analysis was used to determine factors that affect progression of new onset SE to refractory status epilepticus (RSE) and mortality. Among 114 patients with new onset SE, 52 patients progressed to RSE. Sixty seven (58.7%) were men. New onset RSE patients were younger than new onset SE patients (mean 35.9 ± standard deviation18.2 versus 28.7 ± 20.2 years; p = 0.050). Cryptogenic aetiology was the most significant determinant of progression of new onset SE to RSE (Exp [β] = 5.68; p = 0.001). The overall mortality in the entire group was 23.7%, significantly higher in new onset RSE group (40.4% versus 9.7%; p < 0.0001). New onset RSE patients with symptomatic and cryptogenic etiology did not differ for clinical characteristics and outcome. Acidosis was the strongest predictor of mortality in the entire cohort (Exp [β] = 8.72; p = 0.005). Nearly half of the patients with new onset SE progressed to RSE. While cryptogenic aetiology determined progression of new onset SE to RSE, acidosis was associated with mortality. The outcome was similar between symptomatic and cryptogenic new onset RSE.     

Efficacy of antibiotic-impregnated external ventricular drains in reducing ventriculostomy-associated infections

Use of an external ventricular drain (EVD) is essential for managing patients with hydrocephalus or intracranial hypertension. While this procedure is safe and efficacious, ventriculostomy-associated infections (VAI) continue to cause significant morbidity. In this study, we evaluated the efficacy of antibiotic-coated EVD (AC-EVD) in reducing the occurrence of VAI. Between July 2007 and July 2009, 203 patients underwent placement of an EVD. A total of 145 of these patients met the inclusion criteria, with 76 patients (52.4%) receiving AC-EVD and 69 patients (47.6%) receiving uncoated EVD. Ten patients (6.9%) developed VAI, of whom three were in the AC-EVD group and seven were in the uncoated EVD group (p = 0.19). The mean duration between catheter insertion and positive cerebrospinal fluid culture was significantly greater in the AC-EVD group versus the uncoated EVD group (15 ± 4 days versus 4 ± 2 days, respectively; p = 0.001). In the uncoated EVD group, 17 of 69 patients (24.6%) were dead at 3 years versus 12 of 76 (15.8%) patients in the AC-EVD group (p = 0.21). The overall VAI rate was 6.9% with a trend toward lower infection rates in the AC-EVD group compared to the uncoated EVD group (3.9% versus 10.1%, respectively; p > 0.05).     

Clinical predictors for favorable outcomes from endovascular recanalization in wake-up stroke

Background and purposePatients who have acute stroke symptoms present on awakening are ineligible for standard intravenous thrombolysis due to the unclear onset time of symptoms. Some of these wake-up stroke (WUS) patients may benefit from endovascular recanalization. This study aimed to evaluate clinical predictors of outcomes from endovascular recanalization in WUS patients.MethodsForty-one WUS patients with internal carotid (ICA) or middle cerebral artery (MCA) occlusion treated with endovascular recanalization were reviewed. Regression analysis was performed to measure clinical predictors of outcomes from endovascular recanalization in WUS patients.ResultsThe mean initial NIHSS score was 16.41 ± 4.96 (5–24). The mean symptom recognition-to-door time (SRDT) was 108.85 ± 65.80 (19–230) min. Successful recanalization (TICI 2b-3) was achieved in 29 patients (70.7%). Thirty-four patients improved on NIHSS (amount 7.59 ± 4.84, range; 1–17) at 7 days after recanalization. At 90 days after recanalization, a mRS of ≤2 was achieved in 19 patients (46.3%) and a mRS of ≤3 was achieved in 24 patients (58.5%). No symptomatic intracerebral hemorrhage occurred. Multivariate regression analysis identified SRDT (P = 0.019), successful recanalization (P = 0.005), and hypertension (P = 0.013) were factors associated with an improvement of the NIHSS score. For a good functional outcome at 90 days, SRDT (P = 0.036) and initial NIHSS score (P = 0.016) were found to be significant predictors.ConclusionsThe results of this study suggest that the SRDT is an independent predictor of both an improvement of NIHSS score and a good functional outcome in endovascular recanalization for WUS patients.     

Higher expression of monocyte chemoattractant protein 1 and its receptor in brain tissue of intractable epilepsy patients

We aimed to explore the pathogenesis of monocyte chemoattractant protein-1 (MCP1) and CC chemokine receptor 2 (CCR2) in brain tissue of patients with intractable epilepsy (IE). Hippocampi or temporal lobe tissues were obtained from 40 patients with IE and five patients without IE who had undergone surgical decompression and debridement. The levels of MCP1 and CCR2 were evaluated using immunohistochemistry. Pearson correlation analysis was employed to evaluate the correlation between levels of MCP1 and CCR2 in IE with or without hippocampal sclerosis (HS) and the disease duration, along with age. Higher levels of MCP1 (11.68 ± 4.68% versus 1.72 ± 1.54%) and CCR2 (11.54 ± 4.65% versus 1.52 ± 1.29%; P < 0.05) were observed in IE patients compared to controls. Expression levels of MCP1 (R = 0.867) and CCR2 (R = 0.835) in IE patients with HS were correlated with the disease duration. However, no correlation was found in IE patients without HS. There was also no correlation between levels of MCP1 and CCR2 in IE patients with age, either with HS or without HS. These results suggest that MCP1 and its receptor may play a role in the pathogenesis and progression of IE.     

Accuracy and safety of targeting using intraoperative “O-arm” during placement of deep brain stimulation electrodes without electrophysiological recordings

The aim of our study was to investigate the accuracy of targeting using intraoperative “O-arm” during deep brain stimulation (DBS) surgery. Intraoperative O-arm (Medtronic, Minneapolis, MN, USA) images were obtained to confirm the accuracy of placement. The difference between intended and actual target coordinates was calculated based on intraoperative images and postoperative CT scan. Euclidian vector error was obtained to estimate the directional error. Correlation of targeting error with the pneumocephalus and the deviation from the planned trajectory was also estimated. Twenty eight DBS leads (globus pallidus internus [GPi], n = 13; subthalamic nucleus [STN], n = 9; ventralis intermedius nucleus [VIM], n = 6) were implanted in 20 patients using the stereotactic Leksell frame (Elekta AB, Stockholm, Sweden) under general anesthesia over a period of 1 year. The mean age was 63.6 ± standard error of the mean (SEM) 15.7 years and 60% of patients were males. The mean absolute difference (+SEM) between intended and actual target in x, y and z coordinates based on intraoperative CT scan was 0.65 ± 0.09 (p = 0.84), 0.58 ± 0.08 (p = 0.98), 1.13 ± 0.10 (p = 0.08), respectively, and postoperative (1 month) CT scan was 0.82 ± 0.15 (p = 0.89), 0.55 ± 0.11 (p = 0.97), and 1.58 ± 0.29 (p = 0.08), respectively. The Euclidean vector error was 1.59 ± 0.10 and 2.16 ± 0.26 based on intraoperative and postoperative images, respectively. There was no statistically significant targeting error based on fusion of intraoperative CT images to either preoperative CT scan or MRI as registration series, the presence of pneumocephalus, deviation from planned trajectory or the anatomical target (STN versus VIM versus GPi) (p > 0.05). Superficial skin infection was encountered in a single patient in this study. The mean total operating room time was 193.5 ± 74.6 minutes. None of the patients required revision in our study. DBS leads can be implanted safely and accurately using intraoperative O-arm with a frame based targeting system and can be used in selected patients.     

Clinical outcomes after decompressive laminectomy for symptomatic ossification of ligamentum flavum at the thoracic spine

Ossification of the ligamentum flavum (OLF) is a rare disease that causes acquired thoracic spinal canal stenosis and thoracic myelopathy. The aim of this study was to investigate clinical outcomes of symptomatic thoracic OLF treated using posterior decompressive laminectomy. We retrospectively analyzed the medical records of 22 patients who underwent posterior decompressive laminectomy for symptomatic thoracic OLF. The surgical results were evaluated using the modified Japanese Orthopaedic Association (JOA) scoring system and Hirabayashi recovery rate. The intensity of pain was evaluated using a visual analog scale (VAS). The mean duration of follow-up was 35.6 months. The mean JOA score was significantly improved at final follow-up (9.18 ± standard deviation of 1.53 points [range, 6–11 points]) compared with before surgery (5.64 ± 2.04 points [range, 3–9 points]) (P < 0.001). The mean Hirabayashi recovery rate was 65.49% (range, 20–100%). Recovery outcomes were excellent in nine patients, good in eight patients, fair in four patients and unchanged in one patient. No patient was classified as deteriorated. The VAS scores were 2.82 ± 3.08 before surgery and 0.59 ± 1.05 at final follow-up (P = 0.001). Surgical complications, which resolved after appropriate and prompt treatment, included dural tear in five patients, cerebrospinal fluid leakage in one patient, immediate postoperative neurologic deterioration in one patient, epidural hematoma in one patient, and wound infection in one patient. Our findings suggest that posterior decompressive laminectomy is an effective treatment for symptomatic thoracic OLF and provides satisfactory clinical improvement, but surgery for thoracic OLF is associated with a relatively high incidence of complications.