Kyphoplasty With a New Device: A Comparison Study

Jian Huang (  wawayjs@sina.com ) Haikou Hospital of Traditional Chinese Medicine https://orcid.org/0000-0002-5434-1148 Ming Chen Haikou Hospital of Traditional Chinese Medicine Zongbo Zhou Haikou Hospital of Traditional Chinese Medicine Zhifu Lu Haikou Hospital of Traditional Chinese Medicine Chuangong Fu Haikou Hospital of Traditional Chinese Medicine Xuejian Gou Haikou Hospital of Traditional Chinese Medicine Zuqing Wu Haikou Hospital of Traditional Chinese Medicine Zhaodong Yan Haikou Hospital of Traditional Chinese Medicine


Surgical technique
All operations were performed by the chief surgeon of spine surgery. All patients were treated with local in ltration anesthesia [7] . All patients were in prone position, with pillows on the chest and ilium [8] . The pedicle of the responsible vertebral body was located and marked by C-arm uoroscopy. The 10'a clock and 2'a clock positions of the pedicle shadow on both sides of the responsible vertebral body were used as puncture points. The experimental group was punctured with a new puncture needle with a diameter of 4.0 mm (Fig. 1), and the puncture points by C-arm uoroscopy was good, Maintain the appropriate lateral tilting angle and upper tilting inclination angle, continue to knock the needle inward, C-arm uoroscopy showed that the needle tip had reached the medial edge of pedicle shadow in the anterior and posterior position, and the needle tip had reached the posterior edge of vertebral body in the lateral position, continue to knock the needle inward for 3mm, removed the inner core of the needle, and had established the working channel. The bone drill was inserted into the working channel on both sides to expand the bone channel in the vertebral body, and then the balloon was placed to expand. The edge of the balloon was close to the upper and lower endplates, reached the cortex around the vertebral body, or the vertebral fracture was restored,and the expansion was stopped. Appropriate PMMA was injected through the working channel (Fig. 2, 3).
The diameter of the puncture needle in the control group was 3.0 mm. After removing the inner core of the puncture needle, the guide needle was put in rst, then the puncture needle cannula was removed, and then the expansion cannula and the working cannula were inserted along the guide needle to establish the working channel. The tip of the working cannula was 3mm in front of the posterior cortex of the vertebral body under C-arm uoroscopy. Finally, the expansion cannula and guide needle were removed, and the working channel was established. The remaining operations was the same as the experimental group.

Postoperative managements
All patients wear waist circumference by nurse guided to walk 2 hours after operation and change wound dressing on time.
E cacy evaluation All patients were followed up for at leat 12 months after treatment. The operation time and intraoperative blood loss of all patients were recorded. Intraoperative blood loss = (preoperative hemoglobinpostoperative hemoglobin) / preoperative hemoglobin × 100%. VAS pain score standard [9] was used to evaluate the improvement of pain. From 0 to 10 points, the higher the score, the more obvious the pain. VAS scores before operation, 2h, 4h and 48h after operation were recorded. The vertical height of the anterior edge of the upper and lower endplates in the median sagittal plane of the vertebral body was measured by lateral X-ray lm [10] . The ratio of anterior height of injured vertebral body = (anterior height of injured vertebral body / average height of anterior edge of upper and lower vertebral body of injured vertebral body) × 100%. The anterior height of injured vertebral body was recorded before operation, 3 days after operation and the last follow-up. The vertical height of the middle of the upper and lower endplates in the median sagittal plane of the vertebral body was measured by lateral X-ray lm. The ratio of middle height of injured vertebral body = (middle height of injured vertebral body / average height of middle of upper and lower vertebral body of injured vertebral body) × 100%. The middle height of injured vertebral body was recorded before operation, 3 days after operation and the last follow-up.The angle between the extension lines of the upper and lower endplates in the median sagittal plane of the vertebral body was measured by lateral X-ray lm. The wedge angle of injured vertebral body was recorded before operation, 3 days after operation and the last follow-up [11] . The number of C-arm uoroscopy during the operation and the total cost of the operation were recorded.
Statistical methods SPSS 26.0 was used for data analysis. The measurement data were expressed by mean ± standard deviation. For intergroup comparison, variance homogeneity F test was used rst, then independent sample t / t' test was used, and paired sample t test was used for intragroup comparison. The count data were expressed by the number of cases and percentage, and the comparison of counting data was performed by chi-square test. Test level α = 0.05, bilateral test.

General results
All patients had no serious complications, Such as PMMA leakage, nerve root and spinal cord injury, wound infection. There were no signi cant difference in gender, age and clinical manifestations between the two groups ( Table 1).

Comparison of operation time intraoperative blood loss
There were signi cant difference in operation time and intraoperative blood loss between the two groups ( Table 2).

Comparison of VAS scores
There was no signi cant difference in VAS scores between the two groups on preoperation. In each group,there were signi cant difference in VAS scores between the preoperation and 2h, 4h and 48h after operation. But there was no signi cant difference in VAS scores between the two groups at 2h, 4h and 48h after operation ( Table 3).

Comparison of ratio of anterior height of injured vertebral body
There was no signi cant difference in the ratio of anterior height of injured vertebral body between the two groups before operation. In each group, there were signi cant difference in the ratio of anterior height of injured vertebral body between the preoperation and 3 days after operation, last follow-up. But there was no signi cant difference in the ratio of anterior height of injured vertebral body between the two groups at 3 days after operation and last follow-up ( Table 4).

Comparison of ratio of middle height of injured vertebral body
There was no signi cant difference in the ratio of middle height of injured vertebral body between the two groups before operation. In each group, there were signi cant difference in the ratio of middle height of injured vertebral body between the preoperation and 3 days after operation, last follow-up. But there was no signi cant difference in the ratio of middle height of injured vertebral body between the two groups at 3 days after operation and last follow-up ( Table 5).

Comparison of wedge angle of injured vertebral body
There was no signi cant difference in the wedge angle of injured vertebral body between the two groups before operation. In each group, there were signi cant difference in the wedge angle of injured vertebral body between the preoperation and 3 days after operation, last follow-up. But there was no signi cant difference in the wedge angle of injured vertebral body between the two groups at 3 days after operation and last follow-up (Table 6).
Comparison of the number of C-arm uoroscopy during the operation and the total cost of the operation There were signi cant difference in the number of C-arm uoroscopy during the operation between the two groups. But there was no signi cant difference in the total cost of the operation between the two groups ( Table 7).

Discussion
In the 1980s, Deramand and Galibert of France injected PMMA into C2 vertebral body under X-ray uoroscopy to treat osteonecrosis of vertebral body caused by hemangioma, in order to alleviate longterm pain of patients, and achieved satisfactory clinical effect after 3 years of follow-up. This technology was known as PVP [12] , which opened up a precedent for minimally invasive treatment of osteoporotic vertebral fracture. However, PVP can not effectively restore the height of vertebral body, correct kyphosis deformity, and better reconstruct the stability of spine, and bone cement is easy to leak outward along the fracture, which increases the risk of surgery [13] . In 1994, American medical scientists designed PKP, that was, percutaneous implanting expandable balloon into the diseased vertebral body to restore the compression fracture and form a cavity in the vertebral body, and then lling the cavity with bone cement, increasing vertebral strength and stiffness [14] , which can relieve pain, correct kyphosis, reconstruct spinal stability, and improve the quality of life of patients [15] . The possible analgesic mechanism was that bone cement is anchored in the vertebral body to x osteoporotic microfracture, increase the stability of vertebral body and reduce the stimulation of pain nerve endings in vertebral body. Or the polymerization exothermic and toxic effect of bone cement destroy the nerve endings and in ammatory pain factors in the vertebral body, change the microenvironment in the vertebral body, reduce the pain sensitivity, block the generation of pain mediators, and achieve the analgesic effect [16][17][18] .
PKP has a wide range of applications. For primary osteoporotic vertebral compression fractures. It can be selected if the pain can not be alleviated or wanting to prevent the related complications caused by longterm bed rest. For vertebral benign tumor or malignant tumor vertebral bone metastasis, PKP surgery can also be selected to improve the pain symptom. For old vertebral compression fractures or the diagnosis is Kummell disease, if MRI indicates that the vertebral body still has high signal, and the pain symptoms are consistent with imaging, PKP can also improve the pain symptom [19] . Tohmeh Ag et al. [20] compared the biomechanical e cacy of unilateral and bilateral transpedicular kyphoplasty through uniaxial compression test, and found that there was no signi cant difference between unilateral and bilateral approaches. However, we believe that bilateral pedicle puncture and bilateral balloon dilatation can effectively restore the collapsed endplate and reduce the risk of scoliosis.
In the traditional PKP, the puncture needle was used rst, and the puncture needle position by C-arm uoroscopy was satis ed, pulled out the core of the puncture needle, inserted the guide needle, pulled out the puncture needle cannula, inserted the expansion cannula along the guide needle, then inserted the working cannula to 3mm in front of the posterior cortex of the vertebral body, and nally removed the expansion cannula and the guide needle. We used a new puncture needle device instead of the traditional puncture needle. After the position by C-arm uoroscopy was satis ed, we pulled out the inner core of the puncture needle and left the puncture needle cannula in the body as the working channel. Compared with the traditional operation method, it reduces the process of inserting the guide needle, and then gradually inserting the expanding cannula and working cannula through the guide needle. Through comparative study, it was found that the operation time, intraoperative blood loss and the number of C-arm uoroscopy during the operation of the experimental group were better than those of the control group, while there was no signi cant difference in VAS pain score, anterior and middle height of injured vertebral body, wedge angle of injured vertebral body and operation cost between the two groups. It can be seen that the new operation method can shorten the operation time and reduce the radiation exposure rate of surgeons, but it has no effect on the operation effect and operation cost.
However, the sample size of this study is small. In the future work, we will further expand the sample size, and try to improve the operation technology to further shorten the operation time and reduce the radiation exposure rate of surgeons, so as to improve the popularity of PKP.

Conclusion
The new operation method can shorten the operation time and reduce the radiation exposure rate of surgeons, but it has no effect on the operation effect and operation cost, so it can be widely used in clinic.      Figure 1 New puncture needle with a diameter of 4.0mm