Accuracy of Multilevel Registration in Image-Guided Pedicle Screw Insertion for Adolescent Idiopathic Scoliosis

This is a non-final version of an article published in final form in SPINE 35(3): 347-352, 2010.Study Design. Retrospective clinical study. Objective. To assess the accuracy of multilevel registration for skip pedicle screw placement during image-guided, computer-assisted spine surgery, in the setting of adolescent idiopathic scoliosis (AIS). Summary of Background Data. Computerized frameless stereotactic image-guidance has been used recently to improve pedicle screw placement accurately and safety during spine surgery. Because of possible intervertebral motion and usual difference in patients' position between preoperative imaging and surgery, the imaging model and the surgically exposed spine may be significantly discordant. Consequently, current protocols suggested separate registration of each spinal level (single-level registration) before respective pedicle screw placement, a time-consuming process. Moreover, although multilevel registration for lumbar spine has been reported, and that for thoracic spine has not. Methods. A total of 19 patients ( 1 male and 18 females; mean age, 13.9 years) with AIS who underwent multilevel registration for skip pedicle screw placement were included. Variables including surgical time, blood loss, preoperative and 2-year postoperative Cobb angle, correction rate, and postoperative screw position by computed tomography image were evaluated. Mean registration error after point merge and again after surface merge were recorded for each consecutive vertebra of each case. Results. Mean surgical time was 310 minutes ( range, 168-420 min). Mean blood loss 1138 g (range, 300-2300 g). Cobb angle before operation and at 2 years postoperation was 62.4 degrees (43 degrees-100 degrees) and 21.6 degrees (9 degrees-42 degrees), respectively. Mean correction rate 66.2% (39.7%-84.5%). Total 265 screws were inserted with computed tomography-based navigation system. Pedicle violation was observed in only 4 screws (1.5%). No neurovascular complication occurred. After point merge, average Mean registration error of all cases was 1.69 +/- 0.52 mm, and after surface merge was 0.51 +/- 0.16 mm. Conclusion. Multilevel registration may decrease operative time without compromising accuracy of pedicle screw placement afforded by this technique in the setting of AIS.http://journals.lww.com/spinejournal/pages/default.aspx | http://journals.lww.com/spinejournal/pages/default.aspxArticleSPINE. 35(3):347-352 (2010)journal articl

Comparison in bone turnover markers during early healing of femoral neck fracture and trochanteric fracture in elderly patients

Healing of fractures is different for each bone and bone turnover markers may reflect the fracture healing process. The purpose of this study was to determine the characteristic changes in bone turnover markers during the fracture healing process. The subjects were consecutive patients with femoral neck or trochanteric fracture who underwent surgery and achieved bone union. There were a total of 39 patients, including 33 women and 6 men. There were 18 patients (16 women and 2 men) with femoral neck fracture and 21 patients (17 women and 4 men) with trochanteric fracture. Serum bone-specific alkaline phosphatase (BAP) was measured as a bone formation marker. Urine and serum levels of N-terminal telopeptide of type I collagen (NTX), as well as urine levels of C-terminal telopeptide of type I collagen (CTX) and deoxypyridinoline (DPD), were measured as markers of bone resorption. All bone turnover markers showed similar changes in patients with either type of fracture, but significantly higher levels of both bone formation and resorption markers were observed in trochanteric fracture patients than in neck fracture patients. BAP showed similar levels at one week after surgery and then increased. Bone resorption markers were increased after surgery in patients with either fracture. The markers reached their peak values at three weeks (BAP and urinary NTX), five weeks (serum NTX and DPD), and 2–3 weeks (CTX) after surgery. The increase in bone turnover markers after hip fracture surgery and the subsequent decrease may reflect increased bone formation and remodeling during the healing process. Both fractures had a similar bone turnover marker profile, but the extent of the changes differed between femoral neck and trochanteric fractures

Computer-assisted hemivertebral resection for congenital spinal deformity

No studies have reported on osteotomies utilizing a navigation system in congenital scoliosis surgery. This study aimed to evaluate the surgical outcomes of eight patients with congenital scoliosis or kyphoscoliosis due to hemivertebrae treated by computer-assisted hemivertebral resection using only a posterior approach. Eight consecutive patients (two scoliotics and six kyphoscoliotics) managed by computer-assisted hemivertebral resection using only a posterior approach with transpedicular instrumentation were investigated retrospectively. A CT-based navigation system was used to confirm the positions of the vertebra, spinal cord and aorta in real-time when we inserted a pedicle screw and conducted the osteotomy. The mean patient age at surgery was 18 years (range 11-41 years). The mean follow-up was 46 months (range 18-84 months). Before surgery, the mean kyphotic curve was 55.8A degrees (range 26-83A degrees), and the mean scoliotic curve was 50.0A degrees (range 36-62A degrees). At the final follow-up period, the curves averaged 23.2A degrees (range 15-40A degrees) and 31.6A degrees (range 21-44A degrees), respectively, yielding kyphotic angle corrections of 32.7A degrees (range 11-58A degrees) and Cobb angle correction rates of 36.8% (range 24.1-48.3%). A total of 72 pedicle screws were inserted with the navigation system, and two screws revealed a perforating pedicle. No neurovascular complications occurred. The perforation rate was 2.8%. Hemivertebral resection via a single posterior approach is less invasive than combined anterior and posterior approaches; however, this procedure increases the risk of spinal cord and vascular injuries. Computer-assisted hemivertebral resection enables safe and accurate performance of a hemivertebral resection via a single posterior approach.ArticleJOURNAL OF ORTHOPAEDIC SCIENCE. 16(5):503-509 (2011)journal articl

Evaluation of clinical results and quality of life after surgical reconstruction for rheumatoid cervical spine

BACKGROUND CONTEXT: The EuroQol (EQ-5D) is a widely used comprehensive measure of health-related quality of life. There has been no study that has evaluated the health-related quality of life before and after the surgical reconstruction of rheumatoid arthritis (RA) cervical spine lesions using EQ-5D. PURPOSE: The present study aimed to evaluate the improvement of quality of life before and after surgical reconstruction of rheumatoid cervical spine using EQ-5D, and the surgical outcomes of cervical spine affected by RA. STUDY DESIGN: A retrospective study of the patients who underwent surgical reconstruction of cervical disorders in RA. PATIENT SAMPLE: Twenty-five patients (seven men, 18 women, mean age 62.2 years) who underwent surgical reconstruction of cervical disorders in RA were enrolled. OUTCOME MEASURES: Japanese Orthopaedic Association (JOA) score and EQ-5D. METHODS: Clinical symptoms were evaluated before surgery and at 2 years after surgery by measuring the JOA score. We also investigated health-related quality of life before surgery and outcome at 2 years after surgery using the EQ-5D questionnaire. RESULTS: Mean observation period was 46.3 months. Mean JOA score significantly improved from 9.1 +/- 4.5 points before surgery to 12.4 +/- 2.8 at the 2 years after surgery (p=.0001). All the EQ-5D data were improved at the 2 years after surgery, compared with the data before surgery; especially, pain (p=.005), usual activity (p=.005), mobility (p=.008), and anxiety/depression (p=.02) were significantly improved. Utility weight was 0.37 +/- 0.27 before surgery and 0.56 +/- 0.26 at the 2 years after surgery, showing significant improvement at the 2 years after surgery compared to before surgery (p=.002). CONCLUSIONS: The surgical reconstruction of rheumatoid cervical spine has been demonstrated to improve patients' health-related quality of life.ArticleSPINE JOURNAL. 13(4):391-396 (2013)journal articl

Mid-term results of computer-assisted cervical reconstruction for rheumatoid cervical spines

Study design A retrospective single-center study. Summary and background We routinely have used C1-C2 transarticular and cervical pedicle screw fixations to reconstruct highly destructed unstable rheumatoid arthritis (RA) cervical lesions. However, there is little data on midterm results of surgical reconstruction for rheumatoid cervical disorders, particularly, cervical pedicle screw fixation. Objectives The purpose of this study was to evaluate the mid-term surgical results of computer-assisted cervical reconstruction for such lesions. Methods Seventeen subjects (4 men, 13 women; mean age, 61 +/- 9 years) with RA cervical lesions who underwent C1-C2 transarticular screw fixation or occipitocervical fixation, with at least 5 years follow-up were studied. A frameless, stereotactic, optoelectronic, CT-based image-guidance system, was used for correct screw placement. Variables including the Japanese Orthopaedic Association (JOA) score, Ranawat class, EuroQol (EQ-5D), atlantodental interval, and Ranawat values before, and at 2 and 5 years after surgery, were evaluated. Furthermore, screw perforation rates were evaluated. Results The lesions included atlantoaxial subluxation (AAS, n = 6), AAS + vertical subluxation (VS, n = 7), and AAS + VS + subaxial subluxation (n = 4). There was significant neurological improvement at 2 years after surgery, as evidenced by the JOA scores, Ranawat class, and the EQ-5D utility weight. However, at 5 years after surgery, there was a deterioration of this improvement. The Ranawat values before, and at 2 and 5 years after surgery, were not significantly different. Major screw perforation rate was 2.1 %. No neural and vascular complications associated with screw insertion were observed. Conclusions Subjects with rheumatoid cervical lesions who underwent C1-C2 transarticular screw fixation or occipitocervical fixation using a pedicle screw had significantly improved clinical parameters at 2 years after surgery. However, there was a deterioration of this improvement at 5 years post surgery.ArticleJOURNAL OF ORTHOPAEDIC SCIENCE. 18(6):916-925 (2013)journal articl

INFLUENCE OF WETNESS ON EFFICIENCY OF THE FULL SCALE SIZE LOW PRESSURE TURBINES

ABSTRACT Efficiencies of 60Hz full size test turbines were measured in various wet steam conditions to reveal the wetness impact on the performance. We changed the wetness and stage load conditions independently under the condition of constant steam mass flow rate in the low pressure turbine. The test results told that the stage efficiency decreases with the increasing of wetness as many studies showed, furthermore, the stage efficiency decreases more in smaller load conditions than in the design point. In addition, blade length effects were examined by comparing two types of LP turbine to be found that the longer case got more deficits at the same wetness. Some theoretical evaluations were tried and a combination of some simple loss models explained the tendencies above, qualitatively. The evaluation showed that absolute value of mechanical wet loss such as braking loss remained unchanged regardless of load conditions, so in low load condition, ratio of mechanical loss to stage load increased, resulting decrease of stage efficiency. It also showed that increasing wet loss at the longer blade was mainly because higher circumferential velocity caused larger mechanical wet loss such as braking loss. INTRODUCTION The steam in low pressure steam turbines operating in thermal power plants is generally expanded to a vacuum, and the turbine exit operates in wet-steam conditions. In geothermal and nuclear power plants, almost all the turbine stages operate in wet steam because the inlet steam temperature is lower than that of thermal power plants. The wet steam includes variou

Challenges of Transarticular Screw Fixation in Young Children: Report of Surgical Treatment of a 5-Year-Old Patient's Unstable Os-Odontoideum

Surgical procedures for atlantoaxial (C1–C2) fusion in young children are relatively uncommon. The purpose of this study was to report on a surgical treatment for a case of atlantoaxial instability caused by os-odontoideum in association with quadriparesis and respiratory paralysis in a 5-year-old girl. We present the patient's history, physical examination, and radiographic findings, describe the surgical treatment and a five year follow-up, and provide a literature review. The instability was treated by halo immobilization, followed by C1–C2 transarticular screw fixation using a computed tomography-based navigation system. At the five year follow-up, the patient had made a complete recovery with solid union. The authors conclude that C1–2 transarticular screw fixation is technically possible as in a case of atlantoaxial instability in a five-year-old child

Comparison of Spinous Process-Splitting Laminectomy versus Conventional Laminectomy for Lumbar Spinal Stenosis

Study DesignSeventy-five patients who had been treated for lumbar spinal stenosis (LSS) were reviewed retrospectively.PurposeInvasion into the paravertebral muscle can cause major problems after laminectomy for LSS. To address these problems, we performed spinous process-splitting laminectomy. We present a comparative study of decompression of LSS using 2 approaches.Overview of LiteratureThere are no other study has investigated the lumbar spinal instability after spinous process-splitting laminectomy.MethodsThis study included 75 patients who underwent laminectomy for the treatment of LSS and who were observed through follow-ups for more than 2 years. Fifty-five patients underwent spinous process-splitting laminectomy (splitting group) and 20 patients underwent conventional laminectomy (conventional group). We evaluated the clinical and radiographic results of each surgical procedure.ResultsJapanese Orthopaedic Association score improved significantly in both groups two years postoperatively. The following values were all significantly lower, as shown with p-values, in the splitting group compared to the conventional group: average operating time (p=0.002), postoperative C-reactive protein level (p=0.006), the mean postoperative number of days until returning to normal body temperature (p=0.047), and the mean change in angulation 2 years postoperatively (p=0.007). The adjacent segment degeneration occurred in 6 patients (10.9%) in the splitting group and 11 patients (55.0%) in the conventional group.ConclusionsIn this study, the spinous process-splitting laminectomy was shown to be less invasive and more stable for patients with LSS, compared to the conventional laminectomy