Shin Yuan Chen

Efficacy of anterior cervical fusion: comparison of titanium cages, polyetheretherketone (PEEK) cages and autogenous bone grafts.

This retrospective study was designed to analyze and compare the efficacy and outcomes of anterior cervical fusion using titanium cages, polyetheretherketone (PEEK) cages and autogenous tricortical bone grafts. Fifty-five patients who underwent segmental anterior discectomy with a follow-up period up to 12 months enrolled in this study. They were divided into three groups: titanium cage with biphasic calcium phosphate ceramic (Triosite; Zimmer, Berlin, Germany) in group A (n=27); PEEK cage with Triosite in group B (n=9); and autogenous tricortical iliac crest bone graft in group C (n=19). The fusion rates after 6 months were 37.21% in group A , 93.3% in group B, and 84.85% in group C. The fusion rates after 1 year in groups A, B, and C were 46.51%, 100% and 100%, respectively. The PEEK cage is a viable alternative to autogenous tricortical bone grafts in anterior cervical fusion.

Tophaceous gout of the lumbar spine mimicking infectious spondylodiscitis and epidural abscess: MR imaging findings

We report a case of surgically proven tophaceous gout of the lumbar spine at the L5-S1 level that mimicked infectious spondylodiscitis and epidural abscess on magnetic resonance (MR) images in a 65-year-old woman. The spinal tophi were hypointense on T1-weighted images; focally and strongly hyperintense on T2-weighted images; and heterogeneously, marginally enhancing on contrast-enhanced T1-weighted images. The aim of this report is to emphasize the importance of considering this disease entity in the differential diagnosis of an epidural mass in a patient with chronic back pain.

Surgical and hardware complications in subthalamic nucleus deep brain stimulation

OBJECTIVEnTo assess the surgical and hardware complications in 26 consecutive patients with movement disorders undergoing subthalamic deep brain stimulation (STN-DBS) in early practice at our institute.nnnMETHODSnThe 26 patients in our institute were analyzed retrospectively. Group A included the first eight patients treated while we had no facility for microelectrode recording (MER), 16 intracranial procedures were performed and 8 batteries were implanted. Group B (with MER) included 18 patients, 35 intracranial procedures were performed and 18 batteries were implanted.nnnRESULTSnThe intracranial morbidity was 18.75% in group A and 5.71% in group B. The extracranial morbidity was 37.5% in group A and 16.67% in group B. There was no hardware-related infection in our study. The overall mortality rate was 7.69%, and deaths were not surgical related.nnnCONCLUSIONSnThe associated morbidity is significant in STN-DBS. The use of MER may improve the clinical outcome while decreasing the morbidity.

Application of Intraoperative Ultrasound for Brain Surgery

Objective: Over the past decade, the use of intraoperative image guidance in neurosurgery has gradually gained in importance. Apart from some sophisticated and very expensive techniques, intraoperative ultrasound (IOUS) is a simple and economical technique that allows the surgeon to localize deep-seated lesions under a real-time ultrasonic image display without dissection. The purpose of this study was to present our own preliminary experiences in using this modality during surgery for various intraparenchymal brain lesions. Materials and Methods: In total, 37 patients were enrolled for IOUS monitoring in a recent year, which included 10 infratentorial lesions and 27 supratentorial lesions. All studies were performed using an ultrasound machine with variable 3.5~7.5MHz sector transducers (B&K Medical, Denmark). The echogenicity and pathomorphology between IOUS and computed tomography/magnetic resonance imaging (CT/MRI) of various disease entities were compared. Results: Intracranial structures could be well demonstrated by ultrasound once the skull was opened. Most of the intracranial lesions were hyperechoic, except those with a cystic component. IOUS was more sensitive in demonstrating non-enhanced solid lesions and lesions with a cystic component than was preoperative CT/MRI. In addition, color Doppler IOUS could distinguish abnormal vessels from a hematoma, and could identify components of an arteriovenous malformation (AVM) without difficulty. Conclusions: High-resolution real-time IOUS is a convenient and user-friendly method for identifying, localizing, and characterizing the pathological focus during an operation. Such information is very important and can enhance surgical results.

Complications of Multilevel Anterior Cervical Fusion

Objective: Although anterior cervical fusion is a standard procedure for most anterior cervical lesions, multilevel anterior cervical fusion with or without instrumentation remains a challenge due to the complexity of decision making and the high rate of complications as reported in the literature. Patients and Methods: During the period from June 1994 to June 1999, 49 cases of multilevel segmental anterior cervical fusion were retrospectively reviewed. Levels of fusion were determined mainly according to clinical presentations and related magnetic resonance imaging (MRI) findings. A modified Smith-Robinson surgical procedure and tricortical autogenous bone graft taken from the anterior iliac crest were used in all reviewed cases. Instrumentation was indicated only when there were 3 or more fusion levels, and/or when instability was documented. Complications including a painful donor site, transient dysphagia, instrumentation failure, hematoma formation, and spinal cord injury were analyzed. Results: Thirty-six patients (73.5%) received 2 levels of fusion, 11 patients (22.4%) received 3 levels of fusion, and 2 patients (4%) received 4 levels of fusion. Sixteen of 49 (32.6%) patients received plate and screw fixation. All patients achieved solid fusion by at least the 12-month follow-up. Complications included a painful donor site in 18 patients (36.7%), transient dysphasia in 16 patients (32.6%), instrumentation failure in 4 patients (8%), donor site hematoma in 1 patient (2%), and spinal cord injury in 1 patient (2%). Conclusions: Although the fusion rate of multilevel segmental anterior cervical fusion can be maximized if an autogenous tri-cortical bone graft is used and the stability is reinforced with instrumentation, the morbidity remained high. Alternative fusion materials such as a cage with or without an autogenous bone graft should be considered to avoid a painful donor site; meticulous surgical technique with intermittent retraction blade relaxation may decrease the incidence of dysphasia. Proper patient selection is important for avoiding unnecessary fusion levels and instrumentation.