Herniation of intervertebral disc into thoracolumbar fracture vertebral body leads to malunion of fracture and decrease of intervertebral space height / 中国骨伤

OBJECTIVE@#To analyze the clinical characteristics of intervertebral disc tissue injury and herniation into the vertebral body in thoracolumbar fracture on fracture healing, vertebral bone defect volume and intervertebral space height.@*METHODS@#From April 2016 to April 2020, a total of 140 patients with thoracolumbar single vertebral fracture combined with upper intervertebral disc injury treated with pedicle screw rod system reduction and internal fixation in our hospital. There were 83 males and 57 females, aged from 19 to 58 years old, with an average age of (39.33±10.26) years old. All patients were followed up regularly 6 months, 12 months and 18 months after surgery. The patients with injured intervertebral disc tissue not herniated into the fractured vertebral body were the control group, and the patients with injured intervertebral disc and herniated into the fractured vertebral body were the observation group. By detecting the thoracolumbar AP and lateral X-ray films, CT and MRI of the thoracolumbar segment at different follow-up time, calculate the changes of the wedge angle of the fractured vertebral body, the sagittal kyphosis angle and the height of the superior adjacent intervertebral space, the changes of the fracture healing and bone defect volume after the reduction of the vertebral body, and the changes of the intervertebral disc degeneration grade. The prognosis was evaluated by visual analogue scale(VAS) and Oswestry disability index(ODI). Finally, the differences of the above results among different groups were comprehensively analyzed.@*RESULTS@#All the patients had normal wound healing without complications. A total of 87 patients received complete follow-up data, at least 18 months after internal fixation. Thoracolumbar AP and lateral X-ray films showed that 18 months after the reduction and internal fixation operation, the vertebral wedge angle, sagittal kyphosis angle and the height of the upper adjacent intervertebral space in the observation group were greater than those in the control group(P<0.05). CT scanning showed that the deformity of the fracture healed 12 months after the vertebral body reduction in the observation group and formed a "cavity" of bone defect connected with the intervertebral space, and its volume was significantly increased compared with that before (P<0.05). MRI scanning showed that the degeneration rate of injured intervertebral discs in the observation group was more serious than that in the control group 12 months after operation(P<0.05). However, there was no significant difference in VAS and ODI score at each time.@*CONCLUSION@#Herniation of injured intervertebral disc tissue hernias into the fractured vertebral body leads to increased bone resorption defect volume around the fracture and forms a malunion "cavity" connected with the intervertebral space. This may be the main reason for the change of vertebral wedge angle, the increase of sagittal kyphosis angle and the decrease of intervertebral space height after removal of internal fixation devices.

Anatomical study on the feasibility of a new self-guided pedicle tap / 中国骨伤

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 T to L 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 (>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 (<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 / 中国骨伤

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(>0.05). No significant difference was found between two groups in duration of operation, cement volume, VAS, ODI and Cobb angle(>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(>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(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(<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.

Imaging study and applied research of the puncture angle in unilateral percutaneous vertebroplasty / 中国骨伤

<p><b>OBJECTIVE</b>To clarify the abduction angle and needle insertion point of unilateral percutaneous vertebroplasty by measuring the related parameters of lower thoracic spine and lumbar vertebrae.</p><p><b>METHODS</b>Forty normal adults were included in the study, there were 17 males and 23 females. They were scanned by CT with thickness of 1 mm on T10-L5. The coross-section figures of pedicle of vertebral arch, zygapophysial joints, transverse process were choosed, and the maximal and minimal angle of transpedicular puncture, the puncture distance to posterior midline were measured by the image processing software of CT.</p><p><b>RESULTS</b>The data of pucturing angle and point distance had a increasingly trend from T10 to L5 in overall, including a slight decrease from T10 to T12, then was gradually increased until L5, where the maximum was got. According to the measurement, the unilateral percutaneous vertebroplasty were performed, and postoperative Cobb angle of 60 patients were obviously corrected, VAS had significantly decreased(<0.05).</p><p><b>CONCLUSIONS</b>Preoperative measurement of relevant parameters can guide the operation, improve the successful rate of unilateral puncture.</p>