[Anatomical study on the feasibility of a new self-guided pedicle tap].

OBJECTIVE: To evaluate the accuracy and safety of pedicle screw placement using a new self-guided pedicle tap. METHODS: According to the anatomical characteristics of the pedicle, a new self-guided pedicle tap was developed. Six adult spinal specimens including 4 males and 2 females were selected and tapped thread on the right and left sides of each pair of pedicles from the same segment T1 to L5 with traditional taps (control group) and new self-guided pedicle taps (experimental group), respectively. And the pedicle screws were placed. The screwing time was recorded and compared between two groups. CT scanning was completed to observe the accuracy and safety of the screw placement according to the Heary classification of imaging results. RESULTS: The screwing time of thoracic and lumbar vertebrae in the experimental group were (5.87±1.25) min and(5.45±1.67) min, respectively. While those in the control group were (6.12±1.69) min and (6.22±2.13) min, respectively. Then there was no significant difference in screwing time of thoracic and lumbar vertebrae between two groups (P>0.05). The Heary grade of the pedicle screw showed that Heary gradeⅠand Heary gradeⅠ+Ⅱwere respectively 86 (84.31%) and 96 (94.12%) in the experimental group, 72 (71.29%) and 84 (83.17%) in control group, and the difference between two groups was statistically significant (P<0.05). CONCLUSION: The new self-guided pedicle tap can accurately and safely insert the thoracolumbar pedicle screw, with low cost, easy operation, and good clinical application value.

[Therapeutic effect and imaging study of directional bone cement guide for the treatment of thoracolumbar vertebral compression fractures].

OBJECTIVE: To evaluate the therapeutic effects and bone cement distribution of unilateral percutaneous kyphoplasty (PKP) with oriented bone cement injector for thoracolumbar osteoporotic vertebral compression fractures (OVCFs). METHODS: The clinical data of 211 patients (211 vertebrae) with thoracolumbar osteoporotic compression fractures underwent PKP between July 2016 to July 2018 were retrospectively analyzed. All punctures were performed unilaterally:102 patients in observation group used oriented bone cement injector including 30 males and 72 females with an average age of (68.4±8.9)years old; 109 patients in regular group used traditional bone cement injector including 32 males and 77 females with an average age of (70.4±9.2) years old. The two groups were compared in terms of duration of operation, cement volume, visual analogue scale(VAS), Oswestry Disability Index(ODI), distribution of bone cement, bone cement leakage and Cobb angle modified rate. RESULTS: There were no significant difference in gender, age and fracture vertebra between the two groups(P>0.05). No significant difference was found between two groups in duration of operation, cement volume, VAS, ODI and Cobb angle(P>0.05). In observation group, 10 cases occurred cement leakages, with leakage rate of 9.80%; and in regular group, 11 cases occurred cement leakage, with leakage rate of 10.09%. There was no significant difference in the cement leakage rate between two groups(P>0.05). In observation group, proportion rate of I-IV degree in cement distribution was 60.78%, 19.61%, 9.80%, 9.80%, respectively; while 39.45%, 22.93%, 22.93%, 14.68% in regular group. The I degree of cement cross-filling rate was better in observation group than in regular group(P<0.05). There was no significant difference between two groups in II degree distribution rate of bone cement(P>0.05). From T10 to L5, I degree bone cement distribution rate of both groups showed decline trend. The I degree cement cross-filling rate in L1-L5 was 50% in observation group and 30.23% in regular group(P<0.05). CONCLUSIONS: Oriented bone cement injector can control the direction of bone cement dispersion and achieve effective distribution of bilateral bone cement using unilateral puncture and satisfactory surgical results. It is feasible and effective for unilateral PKP treatment of OVCFs.

Study of phase coherence degradation induced by a tapered semiconductor amplifier with frequency-modulated continuous-wave and pulsed seed lasers.

We investigate the phase coherence between a seed laser and a laser amplified by a tapered semiconductor amplifier (TSA) when the seed laser is either continuous wave (CW) or pulsed. The phase fluctuations in the time domain are employed to describe the degradation of phase coherence induced by a TSA. The amplified laser is measured to be approximately 99.98% coherent with the seed, when the CW or pulsed laser is seeded, at different supplying currents of the TSA. Furthermore, the phase coherence is measured when the seed laser is modulated. The results reveal that the phase coherence degradations induced by the TSA remain the same for a seed laser with and without modulation, when different supplying currents of the TSA are applied.

Modulation transfer spectroscopy of coherent population trapping based on phase-coherent lasers.

A new source of two diode laser beams, spatially separated but optically phase-locked with each other, is used to study the modulation transfer spectroscopy of coherent population trapping resonance (CPT). The spectrum for the (87)Rb D2 line is obtained with narrow linewidth and high signal-to-noise ratio, and analyzed with different experimental parameters. A theoretical analysis of the CPT modulation transfer spectra is deduced from the density matrix equation of motion, and found to be in good agreement with the experimental results.