Ho Yeon Lee

CHARITE versus ProDisc: a comparative study of a minimum 3-year follow-up.

Study Design. A retrospective study. Objectives. To evaluate and compare clinical and radiologic outcomes of the CHARITÉ and ProDisc. Summary of Background Data. There is no clinical report comparing CHARITÉ and ProDisc. Methods. Among a total of 61 patients who underwent total disc replacement, 57 patients followed more than 3 years were enrolled. The CHARITÉ was used in 33 patients and ProDisc in 24. MRI follow-up was possible in 52 patients. Clinical and radiologic data including range of motion (ROM) and facet degeneration of the replaced segment, and degeneration of the disc at the adjacent level were evaluated. Results. Mean percentage improvement of Oswestry Disability Index (ODI) score was 78.9% in the CHARITÉ group and 75.8% in ProDisc group. The mean improvement of the Visual Analogue Scale (VAS) pain score was 72% in the CHARITÉ and 74.2% in ProDisc. There was no statistical difference between 2 groups in improvement rates either of the ODI scores and VAS scores. Degradation of the facets was seen in 36.4% of the CHARITÉ and 32% of the ProDisc. Degradation of disc degeneration at the adjacent level above the index level was seen in 19.4% in the CHARITÉ and 28.6% in the ProDisc. The degradation rates of facet joints and disc at adjacent segment between the 2 groups were not significantly different. Segmental ROM of the replaced segments was well preserved, but ROM of L5–S1 of the ProDisc was significantly less than that of the CHARITÉ. Conclusions. While clinical outcomes of both CHARITÉ and ProDisc groups were fairly good, the facet joint of the index level and the disc at the adjacent level showed an aggravation of the degenerative process in a significant number of patients, regardless of the device used, raising concerns of possible late consequences of total disc replacement, especially regarding facet arthrosis and adjacent segment disease.

Mini-transforaminal lumbar interbody fusion versus anterior lumbar interbody fusion augmented by percutaneous pedicle screw fixation: a comparison of surgical outcomes in adult low-grade isthmic spondylolisthesis.

Study Design Retrospective clinical data analysis. Objective To compare clinical results with radiologic results of 2 fusion techniques for adult low-grade isthmic spondylolisthesis. Summary of Background Data There is clear evidence that lumbar interbody fusion using anterior and posterior approaches provides a high fusion rate, good sagittal alignment, and good clinical outcomes. However, there are no recent studies that compare these 2 fusion techniques. Methods Between March 2004 and December 2004, 48 patients underwent instrumented mini-anterior lumbar interbody fusion (ALIF) and 46 underwent instrumented mini-transforaminal lumbar interbody fusion (TLIF). The mean follow-up periods were 32.6 and 29.7 months, respectively. Results The mean visual analog scale (VAS) scores for back and leg pain decreased, respectively, from 7.7 and 7.5 to 2.9 and 2.7 in the ALIF group and from 7.0 and 6.3 to 2.3 and 2.2 in the TLIF group. The mean Oswestry disability index (ODI) scores improved from 51.4% to 23.2% in the ALIF group and from 52% to 14.4% in the TLIF group. In both groups, the VAS and ODI scores significantly changed preoperatively to postoperatively (P<0.001). However, statistical analysis showed no significant difference in postoperative VAS/ODI scores between groups. Radiologic evidence of fusion was noted in 95.8% and 92.3% of the patients in the ALIF group and the TLIF group, respectively. In both the groups, changes in the disc height, segmental lordosis, degree of listhesis, and whole lumbar lordosis (WL) between the preoperative and postoperative periods were significant except for WL in the TLIF group. The amount of change between preoperative and postoperative disc height, segmental lordosis, and WL demonstrated significant intergroup differences (P<0.05). Conclusions The mini-ALIF group demonstrated key radiographic advantages compared with the mini-TLIF group for adult low-grade isthmic spondylolisthesis. However, clinical and functional outcomes did not demonstrate significant differences between groups.

The clinical characteristics and risk factors for the adjacent segment degeneration in instrumented lumbar fusion.

Study Design A retrospective study. Objective The aims of this study were to evaluate the clinical significance of, characteristics of, and risk factors for adjacent segment degeneration (ASD) in patients who have undergone instrumented lumbar fusion. Summary of Background Data ASD has been considered a potential long-term complication of spinal arthrodesis. However, the exact mechanisms and risk factors related to ASD are not completely understood. Methods A total of 48 patients who underwent instrumented lumbar fusion at L4-5 and had minimal ASD preoperatively were evaluated. The patients were divided into 2 groups at follow-up according to the development of ASD defined by radiologic criteria. Through review of their medical records and the radiologic files, the following variables were evaluated in the 2 groups: basic demographic data, body weight, body height, body mass index, bone mineral density, types of surgical approaches, preoperative and postoperative segmental and lumbar lordosis, and clinical outcomes. Results ASD was found in 30 (62.5%) patients. The variables that showed statistical intergroup differences were the mean age at surgery, the mean difference in the degree of preoperative from postoperative lumbar lordosis, and the proportion of patients who underwent anterior lumbar interbody fusion. However, there were no statistically significant intergroup differences in the Japanese Orthopedic Association score at 1-year postoperatively or at the final follow-up, or in the recovery rate, success rate, and complication rate. Conclusions Radiographic ASD is relatively common long-term finding associated with instrumented lumbar fusion. However, radiographic evidence of ASD does not necessarily correlate with a poor outcome. Our results suggest that advanced age, anterior lumbar interbody fusion, and the restoration of the preoperative standing lumbar lordosis may have a protective effect against the development of ASD.

Partial disc replacement with the PDN prosthetic disc nucleus device: early clinical results.

The aim of this study was to evaluate the efficacy of the PDN prosthetic disc nucleus device for the treatment of chronic discogenic back pain caused by degenerative disc disease. Among the 48 patients who underwent nucleus replacement surgery from January 2001 through May 2002, 46 patients were followed >6 months. The mean Oswestry Disability Index score was 58.9% preoperatively, and it improved to 18% at the 1-year follow-up. Visual Analogue Pain Scale scores improved from a preoperative mean of 8.5 to 3.1 after 1 year. The mean Prolo Scale score also improved from 5.2 preoperatively to 7.2 at 1 year. Major complications included four cases of device migration, requiring revision surgery, and infection in one patient. According to MacNabs criteria, results were excellent in 5 patients (10.9%), good in 31 (67.4%), fair in 3 (6.5%), and poor in 7 (15.1%). The overall clinical success rate was 78.3%. Nucleus replacement with the PDN device seemed to be effective in treating patients with chronic discogenic back pain caused by degenerative disc disease.

Comparative study of laparoscopic L5–S1 fusion versus open mini-ALIF, with a minimum 2-year follow-up

Anterior lumbar interbody fusion (ALIF) is a widely accepted tool for management of painful degenerative disc disease. Recently, the modern laparoscopic surgical technique has been combined with ALIF procedure, with good early postoperative results being reported. However, the benefit of laparoscopic fusion is poorly defined compared with its open counterpart. This study aimed to compare perioperative parameters and minimum 2-year follow-up outcome for laparoscopic and open anterior surgical approach for L5–S1 fusion. The data of 54 consecutive patients who underwent anterior lumbar interbody fusion (ALIF) of L5–S1 from 1997 to 1999 were collected prospectively. More than 2-years’ follow-up data were available for 47 of these patients. In all cases, carbon cage and autologous bone graft were used for fusion. Twenty-five patients underwent a laparoscopic procedure and 22 an open mini-ALIF. Three laparoscopic procedures were converted to open ones. For perioperative parameters only, the operative time was statistically different (P=0.001), while length of postoperative hospital stay and blood loss were not. The incidence of operative complications was three in the laparoscopic group and two in the open mini-ALIF group. After a follow-up period of at least 2 years, the two groups showed no statistical difference in pain, measured by visual analog scale, in the Oswestry Disability Index or in the Patient Satisfaction Index. The fusion rate was 91% in both groups. The laparoscopic ALIF for L5–S1 showed similar clinical and radiological outcome when compared with open mini-ALIF, but significant advantages were not identified, despite its technical difficulty.

Novel method for setting up 3D navigation system with skin-fixed dynamic reference frame in anterior cervical surgery.

Abstract Purpose: To introduce easy and useful methods using 3D navigation system with skin-fixed dynamic reference frame (DRF) in anterior cervical surgery and to validate its accuracy. Methods: From September 2012 to May 2013, 31 patients underwent anterior cervical surgery and a total of 48 caspar distraction pins were inserted into each cervical vertebra. Every operation was performed using O-arm® navigation system with skin-fixed DRF. To validate the accuracy of these methods, a custom-made metal sleeve was used. In surgical field, through the metal sleeve, the tip of a navigation probe promptly contacts to the tip of caspar pin. We measured the vertical and horizontal distances and the angular deviation in sagittal plane between the caspar pin and the navigation probe on the virtual images and evaluated accuracy of navigation system with skin fixed DRF. Results: Total 31 (males 20, females 11) patients and 48 caspar pins were included in this study. The mean horizontal distance between the caspar pin and the navigation probe displayed in navigation monitor was 0.49 ± 0.71 mm. The mean vertical distance between the caspar pin and the navigation probe displayed in navigation monitor was 0.88 ± 0.93 mm. And the mean angular deviation in sagittal plane between the caspar pin and the navigation probe displayed in navigation monitor was 0.59 ± 0.55°. Conclusions: 3D navigation system with skin-fixed DRF in anterior cervical surgery is a simple and reliable method and it can be a helpful supplement to a spine surgeon’s judgement.