Entanglement generation in trapped-ion systems has relied thus far on two distinct but related geometric phase gate techniques: Mølmer-Sørensen and light-shift gates. We recently proposed a variant of the light-shift scheme where the qubit levels are separated by an optical frequency [B. C. Sawyer and K. R. Brown, Phys. Rev. A 103, 022427 (2021)]. Here we report an experimental demonstration of this entangling gate using a pair of ${{}^{40}\mathrm{Ca}}^{+}$ ions in a cryogenic surface-electrode ion trap and a commercial, high-power, 532 nm Nd:YAG laser. Generating a Bell state in $35\mu \mathrm{s}$, we directly measure an infidelity of $6(3)\times {10}^{-4}$ without subtraction of experimental errors. The 532 nm gate laser wavelength suppresses intrinsic photon scattering error to $\sim 1\times {10}^{-5}$.

Object: Both anterior cervical discectomy with fusion (ACDF) and anterior cervical corpectomy with fusion (ACCF) are used to treat cervical spondylotic myelopathy; however, there is currently no evidence for the superiority of one over the other in terms of patient-rated outcomes. This comparative effectiveness study compared the patient-rated and radiographic outcomes of 2-level ACDF versus 1-level ACCF. Methods: This single-center study was nested within the EuroSpine Spine Tango data acquisition system. Inclusion criteria were the following: consecutive patients presenting with signs of cervical spondylotic myelopathy who underwent 2-level ACDF or 1-level ACCF between 2004 and 2011. Before and 12 months after surgery, patients completed the multidimensional Core Outcome Measures Index (COMI) and also rated global treatment outcome and satisfaction with care on 5-point Likert scales. Cervical lordosis, segmental height, and fusion rate were assessed radiographically before and immediately after surgery and at the last follow-up (20.4 ± 13.7 months, mean ± SD). Results: In total, 118 consecutive patients (80 in the ACDF group and 38 in the ACCF group) were included. Age, sex, comorbidity, baseline symptoms, baseline radiographic data, operation duration, and complication rates did not differ significantly between the 2 groups. Blood loss was significantly (p < 0.04) lower in the ACDF group. Postoperative mean segmental height was significantly (p = 0.0006) greater for ACDF (42.0 ± 4.2 mm, mean ± SD) than for ACCF (39.0 ± 4.0 mm), and global average lordosis improved to a significantly (p = 0.003) greater extent in ACDF (by 1.6° ± 4.1°) than in ACCF (by −1.0° ± 4.0°). Fusion rates for ACDF were 97.5% and for ACCF were 94.7% (p = 0.59). The 12-month patient-rated outcomes did not differ significantly between ACDF and ACCF: 82.4% and 68.6% had a good global outcome (operation helped/helped a lot) (p = 0.10), 86.5% and 82.9% were satisfied/very satisfied with care (p = 0.62), and the reduction in the multidimensional COMI was 2.8 ± 2.7 and 2.2 ± 3 points (p = 0.30), respectively. The postoperative increase in lordosis angle showed low but significant correlations with the improvement in arm pain (r = 0.25, p = 0.014), highest pain (r = 0.25, p = 0.013), and function (r = 0.24, p = 0.016). Conclusions: Both ACDF and ACCF are safe and effective in the treatment of cervical spondylotic myelopathy, indicated by similarly good patient-rated outcomes 1 year after surgery. This precludes any conclusions regarding the superiority of one technique over the other, although it should be noted that ACDF resulted in less blood loss and greater improvements in cervical lordosis and segmental height than ACCF. Patients with improved lordosis angle had a better clinical outcome.

The Barrow Neurological Institute (BNI) scale is a novel quantitative scale measuring maximal subarachnoid hemorrhage (SAH) thickness to predict delayed cerebral ischemia (DCI). This scale could replace the Fisher score, which was traditionally used for DCI prediction. To validate the BNI scale. All patient data were obtained from the prospective aneurysmal SAH multicenter registry. In 1321 patients, demographic data, BNI scale, DCI, and modified Rankin Scale (mRS) score up to the 1-yr follow-up (1FU) were available for descriptive and univariate statistics. Outcome was dichotomized in favorable (mRS 0-2) and unfavorable (mRS 3-6). Odds ratios (OR) for DCI of Fisher 3 patients (n = 1115, 84%) compared to a control cohort of Fisher grade 1, 2, and 4 patients (n = 206, 16%) were calculated for each BNI grade separately. Overall, 409 patients (31%) developed DCI with a high DCI rate in the Fisher 3 cohort (34%). With regard to the BNI scale, DCI rates went up progressively from 26% (BNI 2) to 38% (BNI 5) and corresponding OR for DCI increased from 1.9 (1.0-3.5, 95% confidence interval) to 3.4 (2.1-5.3), respectively. BNI grade 5 patients had high rates of unfavorable outcome with 75% at discharge and 58% at 1FU. Likelihood for unfavorable outcome was high in BNI grade 5 patients with OR 5.9 (3.9-8.9) at discharge and OR 6.6 (4.1-10.5) at 1FU. This multicenter external validation analysis confirms that patients with a higher BNI grade show a significantly higher risk for DCI; high BNI grade was a predictor for unfavorable outcome at discharge and 1FU.

BACKGROUND: Open surgery has traditionally been preferred for the management of bifurcation middle cerebral artery (MCA) aneurysms. Flow diverting stents present a novel endovascular strategy for aneurysm treatment. OBJECTIVE: To add to the limited literature describing the outcomes and complications in the use of flow diverters for the treatment of these complex aneurysms. METHODS: This is a multicenter retrospective review of MCA bifurcation aneurysms undergoing flow diversion. We assessed post-treatment radiological outcomes and both thromboembolic and hemorrhagic complications. RESULTS: We reviewed the outcomes of 54 aneurysms treated with flow diversion. Four (7.4%) of the aneurysms had a history of rupture (3 remote and 1 acute). Fourteen (25.9%) of the aneurysms already underwent either open surgery or coiling prior to flow diversion. A total of 36 out of the 45 aneurysms (80%) with available follow-up data had adequate aneurysm occlusion with a median follow-up time of 12 mo. There were no hemorrhagic complications but 16.7% (9/54) had thromboembolic complications. CONCLUSION: Flow diverting stents may be a viable option for the endovascular treatment of complex bifurcation MCA aneurysms. However, compared to published series on the open surgical treatment of this subset of aneurysms, flow diversion has inferior outcomes and are associated with a higher rate of complications.

Object: Some patients develop communicating hydrocephalus after meningioma surgery, and this can develop into a serious clinical condition. However, this has rarely been addressed in the literature. Therefore, the authors sought to determine predictive patient variables for the occurrence of postoperative hydrocephalus following skull base meningioma surgery. Methods: For this purpose, the authors retrospectively analyzed all patients who underwent resection of intracranial meningiomas between 1998 and 2009 at the Department of Neurosurgery, University Hospital Zurich, Switzerland. Of 594 patients with meningioma, 227 (38%) had a lesion located at the skull base, and thus were included for analysis. The following patient variables were examined: demographic data (age and sex); tumor number (solitary vs multiple); tumor side and localization within the skull base region (anterior, medial, posterior); infiltration of the cavernous sinus; compression of the optic channel/optic nerve; tumor volume; preoperative embolization (yes/no); duration of surgery; Simpson grade of resection; histopathological features (WHO grade); number of surgeries (single vs multiple); preoperative embolization; duration of hospital stay; tumor recurrence; use of an artificial dural substitute; postoperative infection rate; and clinical outcome (Glasgow Outcome Scale score at discharge and at 3 months, and vital status at last follow-up). Hierarchical clustering, factor analysis, and stepwise regression models revealed a ranking list for the top predictive variables for the occurrence of postoperative hydrocephalus. Results: A total of 35 patients (5.9%) of the cohort of 594 developed communicating postoperative hydrocephalus, with no patient manifesting obstructive hydrocephalus. Of these 35 patients, 18 had a meningioma located at the skull base (18 [7.9%] of 227), in contrast to 17 patients with meningiomas in other locations (17 [4.6%] of 367). The following patient variables correlated with the occurrence of hydrocephalus, as defined by factor analysis: age, duration of surgery, duration of hospital stay, tumor volume, postoperative infection, and preoperative embolization. A stepwise regression analysis of the latter variables identified 2 variables as significantly predictive: age (p = 0.0012) and duration of surgery (p = 0.0013). Conclusions: In this study, the incidence of communicating postoperative hydrocephalus was almost twice as high in patients with skull base lesions as in patients with meningiomas in other locations. Patient age, duration of surgery, duration of hospital stay, tumor volume, postoperative infection, and preoperative embolization were associated with the occurrence of hydrocephalus. In the statistical prediction model, patient age and duration of surgery were the most significant predictors of postoperative hydrocephalus after skull base meningioma surgery.