Expansion Open-door Laminoplasty With Foraminotomy Versus Anterior Cervical Discectomy and Fusion for Coexisting Multilevel Cervical Myelopathy and Unilateral Radiculopathy.

STUDY DESIGN: This was a clinical prospective study. OBJECTIVE: To assess whether clinical and radiologic outcomes differ between expansion open-door laminoplasty with foraminotomy (EOLF) and anterior cervical discectomy and fusion (ACDF) in the treatment of coexisting multilevel cervical myelopathy and unilateral radiculopathy (CMUR). SUMMARY OF BACKGROUND DATA: No reports to date have compared clinical outcomes between anterior and posterior decompression for CMUR. MATERIALS AND METHODS: We prospectively performed ACDF (n=59) in 2004, 2006, and 2008 and EOLF (n=62) in 2005, 2007, and 2009. The Japanese Orthopedic Association (JOA) score and recovery rate were evaluated. For radiographic evaluation, the lordotic angle and range of motion at C2-C7 were investigated. RESULTS: Only 110 patients could be followed for >3 years (EOLF/ACDF: 56/54; follow-up rate, 90.9%). Demographics were similar between the 2 groups. Compared with ACDF, in EOLF group there were shorter operating time (144 vs. 178 min), less bleeding (175 vs. 192 mL), and fewer complications (P<0.05). Results of JOA score and recovery rate, at 3-year postoperative follow-up, showed no statistical difference for the 2 groups. Cervical lordosis of ACDF increased from 13.7 to 16.2 degrees, whereas that of EOLF group decreased from 14.6 to 13.3 degrees (P<0.05). The percentage of range of motion declined in the 2 groups (ACDF/EOLF), 57.4% versus 74.7% (P<0.05). CONCLUSIONS: The 2 surgical procedures have similar clinical effects in treating multisegmental CMUR. However, the EOLF group demonstrated shorter operative time, less blood loss, and fewer complications; therefore, it proved to be a more effective and safer method.

[Analysis of risk factors of axial symptoms after single door laminoplasty for cervical myelopathy].

OBJECTIVE: To investigate the risk factors of axial symptoms after single door laminoplasty for cervical myelopathy. METHODS: A retrospective analysis was made on the clinical data of 102 patients with cervical myelopathy who underwent single door laminoplasty and were accorded with selective standard between February 2009 and October 2011. There were 59 males and 43 females, aged 35 to 72 years (mean, 58 years). The disease duration was 1-70 months (mean, 18 months). The operated segments included C3-7 in 58 cases, C3-6 in 23 cases, C4-7 in 15 cases, and C3-5 in 6 cases. The visual analogue scale (VAS) was used to determine whether the patient had axial symptoms (group A) or not (group B). The logistic regression analysis was used to analyze the risk factors of postoperative axial symptoms by assessing the following indexes: preoperative VAS score, preoperative Japanese Orthopaedic Association (JOA) score, gender, age, disease duration, operated segment, operation time, intraoperative blood loss, wearing collar time, preoperative encroachment rate of anterior spinal canal, preoperative cervical curvature, and preoperative cervical range of motion. RESULTS: A total of 102 cases were followed up 18-26 months (mean, 24 months). And no postoperative spinal cord injury, cerebrospinal fluid leakage, or infection occurred. Of 102 cases, 50 had axial symptoms (group A) and 52 had no axial symptoms (group B). There were significant differences in age, wearing collar time, preoperative cervical range of motion, preoperative cervical curvature, and preoperative encroachment rate of anterior spinal canal between 2 groups (P < 0.05), but no significant difference was found in preoperative JOA score and VAS score, blood loss, gender, disease duration, operated segment, and operation time (P > 0.05). The logistic regression analysis showed that the increased preoperative encroachment rate of anterior spinal canal, reduced preoperative cervical curvature, and preoperative cervical range of motion loss were the risk factors for cervical axial symptoms. CONCLUSION: Age, wearing collar time, preoperative cervical range of motion, preoperative encroachment rate of anterior spinal canal, and preoperative cervical

The effects of vertical gradient of disparity and combination mode of features on the occurrence of double fusion in Panum's limiting case.

Panum's limiting case generally refers to the phenomenon that two features presented to one eye and a single feature presented to the other are combined and then perceived as two features at different depths. It is still not clear why experimental results derived from the Panum-type configuration (all lines parallel) support a double fusion viewpoint, but they do not for the Wheatstone-type configuration (one line not parallel to the others). Some experimental results support the double fusion theory, while others do not, even under a small disparity. Here we report that, under a small disparity, when the vertical gradients of the horizontal disparity ofdichoptic feature pairs in previous Wheatstone-type configurations were increased or decreased, the evidence which was considered to be very convincing in previous studies, either supporting or against the double fusion viewpoint, was challenged, and even turned to support the opposite view. Moreover, it was discovered that changes in the way features were arranged altered the results. Together, these results indicate that double fusion is the common basis for all kinds of Panum-type configurations. But for the Wheatstone-type configurations double fusion is also constrained by the vertical gradient of disparity of the configurations in addition to disparity and influenced by the degree of similarity/conflict between binocular cues and monocular cues resulting from different arrangements of features.

Millisecond-accurate synchronization of visual stimulus displays for cognitive research.

A widely adopted approach in cognitive psychology research is to analyze changes in the response time to a stimulus onset in order to infer information about the cognitive functioning of a subject being tested. But current techniques have inherent variations in the timing between stimulus activation and stimulus display of up to tens of milliseconds, thereby introducing significant errors when response time or the latency of neural responses is measured. This article presents a novel yet easy-to-implement solution for improving resolution in the synchronizing of stimulus activation and stimulus display. Unlike traditional methods in which the stimulus onset is set as the time at which the routine for displaying the stimulus is called, this approach uses DirectX to monitor the scan line of CRTs and sets the stimulus onset to the time at which the scan line arrives at the position where the stimulus is to be drawn. This approach removes the uncertainty involved in having a time delay between the activation of the display routine and the actual time at which the display occurs, improving the accuracy of response time and latency period measurements to within 200 microsec. With a specially developed driver, this solution can generate a trigger signal synchronized precisely with the stimulus onset in all popular Windows systems (including Windows 2000/XP).