BACKGROUND: The blood oxygen saturation is an important physiological parameter of human hfe; it can be affected by multiple factors due to the imbalance of oxygen supply and consumption, and consequently, the normal physical metabolism is affected. The existing manufacturing techniques are complex and are used with higher demands. OBJECTIVE: To investigate the accuracy of the novel reflecting oximeter designed on the basis of reflecting principle in monitoring the variance of blood oxygen saturation with the change of its concentration. DESIGN: To introduce the structure, working principle and design of the reflecting oximeter and make comparative study with adult rabbits as the subjects. SETTING: Cardiopolmonary Bypass Department of Cardiovascular disease hospital of the Chinese Academy of MedicalSciences. MATERIALS: The study was performed at the Departments of Anesthesiology and Cardiopulmonary Bypass of the Cardiovascular Disease Hospital,Chinese Academy of Medical Sciences from August to October in 2001.Ten adult rabbits were selected. METHODS: The oximeter consists of a converter, a driver, a central processing mould and liquid-crystal monitor. It is characterized by the onethree optical cable connected with reflecting probe, postcentral management system and digital displayer. This oxmeter was developed basing on the basis of fixed relationship between blood oxygen saturation and radiant absorbency (or reflecting). In this study,cardiovascular-pulmonary bypass was established on rabbits that were then exposed to oxygen and NO mixture supply of different concentrations,and then the corresponding blood oxygen saturations were determined with the new oximeter and compared with series-wound Baite saturation meter and blood-gas analysis. MAIN OUTCOME MEASURES: The blood oxygen saturation at different concentrations determined with the reflecting oximeter and Baite saturation meter. RESULTS: At the same oxygen concentration, the blood oxygen saturation determined with the new measure was not significantly different from that determined with Baite blood oxygen saturation meter(P＞0.05 ). CONCLUSION: The variance of blood oxygen saturation with the change of oxygen concentration can be detected by the reflecting oximeter with the result similar to that by Baite blood oxygen saturation meter.

Objective:To analyze the correlation between paraspinal muscle parameters and the angle of degenerative thoracolumbar segmental kyphosis.Methods:From November 2021 to April 2023, a total of 90 female patients with lumbar degenerative disease who underwent surgical treatment in the Department of Spine Surgery, Beijing Jishuitan Hospital were retrospectively analyzed. The average age was 67.62±4.98 years (range, 60-80 years), and the average height was 1.58±0.05 m (range, 1.48-1.70 m). Weight 63.79±9.13 kg (range, 47-90 kg), body mass index 25.48±3.35 kg/m 2 (range, 18.37-36.05 kg/m 2). The angle of kyphosis of the thoracolumbar segments was 6.65°±10.38° (range, -17.34° to 9.34°). Disease diagnosis: 32 cases of lumbar disc herniation and 58 cases of lumbar spinal stenosis. Frontal and lateral radiographs of the thoracolumbar segments in the standing position were taken to measure the angle of kyphosis of the thoracolumbar segments; quantitative CT of the thoracolumbar segments and Osirix software were used to measure the parameters of the paravertebral muscles at the levels of T 12, L 3, and L 5, including paravertebral muscle cross-sectional area, skeletal muscle area, and tissue density, the proportion of fat infiltration, and the height-corrected skeletal muscle area index. The correlation between paraspinal muscle parameters and the angle of thoracolumbar segmental kyphosis was analyzed, and the factors affecting the angle of thoracolumbar segmental kyphosis were analyzed using multiple linear regression. Results:Correlation analysis showed a negative correlation between the angle of thoracolumbar segmental kyphosis and the tissue density of T 12 skeletal muscle ( r=-0.303, P=0.004) and L 5 skeletal muscle ( r=-0.219, P=0.038). Age was negatively correlated with T 12 skeletal muscle tissue density ( r=-0.263, P=0.012), T 12 height-corrected skeletal muscle area index ( r=-0.221, P=0.036), T 12 paravertebral muscle cross-sectional area ( r=-0.280, P=0.007), L 3 skeletal muscle tissue density ( r=-0.266, P=0.011) and L 5 skeletal muscle tissue density ( r=-0.290, P=0.006). There was no correlation between bone mineral density and paravertebral muscle parameters ( P>0.05). Multiple linear regression showed that T 12 skeletal muscle tissue density ( β=-1.125, P<0.001), T 12 fat-infiltrated proportion ( β=-0.849, P=0.001), L 3 skeletal muscle tissue density ( β=0.996, P<0.001), and L 3 fat-infiltrated proportion ( β=0.496, P=0.020) were independent factors influencing the angle of thoracolumbar segmental kyphosis . Conclusion:T 12 and L 3 paraspinal muscle density and fat-infiltrated proportion are independent factors affecting the angle of thoracolumbar kyphosis. The smaller the density and fat-infiltrated proportion of T 12 paraspinal muscle, and the larger the density and fat-infiltrated proportion of L 3 paraspinal muscle, the larger the angle of thoracolumbar kyphosis.

BACKGROUNDPercutaneous pedicle screw use has a high rate of cranial facet joint violations (FVs) because of the facet joint being indirectly visualized. Computer-assisted navigation shows the anatomic structures clearly, and may help to lower the rate of FVs during pedicle screw insertion. This study used computed tomography (CT) to evaluate and compare the incidence of FVs between percutaneous and open surgeries employing computer-assisted navigation for the implantation of pedicle screw instrumentation during lumbar fusions.

METHODSA prospective study, including 142 patients having lumbar and lumbosacral fusion, was conducted between January 2013 and April 2014. All patients had bilateral posterior pedicle screw-rod instrumentation (top-loading screws) implanted by the same group of surgeons; intraoperative 3-dimensional computer navigation was used during the procedures. All patients underwent CT examinations within 6 months postoperation. The CT scans were independently reviewed by three reviewers blinded to the technique used.

RESULTSThe cohort comprised 68 percutaneous and 74 open cases (136 and 148 superior-level pedicle screw placements, respectively). Overall, superior-level FVs occurred in 20 patients (20/142, 14.1%), involving 27 top screws (27/284, 9.5%). The percutaneous technique (7.4% of patients, 3.7% of top screws) had a significantly lower violation rate than the open procedure (20.3% of patients, 14.9% of top screws). The open group also had significantly more serious violations than did the percutaneous group. Both groups had a higher violation rate when the cranial fixation involved the L5. A 1-level open procedure had a higher violation rate than did the 2- and 3-level surgeries.

CONCLUSIONSWith computer-assisted navigation, the placement of top-loading percutaneous screws carries a lower risk of adjacent-FVs than does the open technique; when FVs occur, they tend to be less serious. Performing a single-level open lumbar fusion, or the fusion of the L5-S1 segment, requires caution to avoid cranial adjacent FVs.

Aged ; Female ; Humans ; Lumbar Vertebrae ; surgery ; Male ; Middle Aged ; Minimally Invasive Surgical Procedures ; Pedicle Screws ; Prospective Studies ; Zygapophyseal Joint ; surgery