Patient selection method
Inclusion criteria include the following: (a) there was a clear history of trauma; (b) chest and waist pain, limited movement; (c) Denis type B thoracolumbar burst fracture diagnosed by CT scan [8]; (d) TLICS score is 4 points or greater [9–10]; (e) Asia Grade E; (f) 18 years and older; (7) follow-up time is 1 year or longer; (g) institutional Review Board approval was obtained before the study commenced.
Exclusion criteria include the following: (a) the patients were treated with operation for more than 72 hours; (b) with fracture of other parts; (c) treated with manipulation after injury; (d) patients with nerve injury and progressive aggravation; (e) patients with coagulation dysfunction.
General information
60 patients with thoracolumbar burst fracture who were hospitalized from January 2018 to October 2019 were selected and divided into experimental group (33 cases) and control group (27 cases) according to different treatment methods.
Surgical technique
All operations were performed by the chief surgeon of spinal surgery. All patients were anesthetized with combined spinal and epidural anesthesia. All patients were placed in prone position with pillows on their chest and ilium to make the anterior column of the spine under tension in order to reset the spine curvature. The pedicle of the fractured vertebral body was located and marked on skin by C-arm fluoroscopy. The back median longitudinal incision was about 10 cm in length according to fractured vertebrae. and the skin and subcutaneous tissue were cut to the lumbodorsal fascia, and the skin was pulled to both sides of spinous process. At 1.0–2.0 cm on both sides of spinous process, the lumbodorsal fascia was incised longitudinally. In the space between the longissimus muscle and multifidus muscle, the index finger was used to blunt separate and touch the articular process joint and transverse process of the fractured vertebral body, the upper and lower vertebral body. After the attached muscles were cauterized and peeled off with electric knife, the opening cone was used to open pedicle cortex, and pushed forward tilt inward slowly according to the hand feeling. Insert marker and the fluoroscopy position of the marker was satisfactory. Six pedicle screws were inserted into the pedicle, the single axis pedicle screws were inserted into the upper and lower normal vertebrae, the universal axis pedicle screws were inserted into the fracture vertebral. The pedicle screw length of the fracture vertebral was selected to be slightly shorter than the upper and lower normal vertebrae by 5–10 mm. And then the prebent connecting rod was inserted. Firstly, the injured vertebral pedicle screw is tightened, then the lower normal vertebral pedicle screw was tightened, and finally the upper normal vertebral pedicle screw was tightened.
In the experimental group, before tightening the pedicle screw of the lower normal vertebral body, the assistant inserted the screw driver into the screw cap. The operator placed the palm of one hand on the spinous process, the longitudinal axis of the hand was parallel to the spinous process, and the palm of the other hand was placed on the back of the front hand, and the pressure was applied vertically to the ventral side in order to reset the fracture. The force was appropriate to feel the spinous process move to the ventral side. The procedure lasted 20 seconds.The another assistant should prop apart the injured vertebral pedicle screw and the normal vertebral pedicle screw. Then the assistant tightened the screw cap. The injured vertebral and upper normal vertebral were treated with the same method (Fig. 1).
In the control group, there was no manual pressure reduction when the injured vertebral and the upper and lower normal vertebral were proped apart (Fig. 2).
Postoperative managements
All patients were treated with antibiotics for 48 hours after operation. They were treated with dehydration and neurotrophic therapy routinely. Three to five days after the operation, the patients should wear the thoracolumbar brace and try to walk.
Efficacy 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 hemoglobin - postoperative hemoglobin) / preoperative hemoglobin × 100%. VAS pain score standard [6] 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, 3 days after operation and the last follow-up were recorded. The anterior vertical height of the median sagittal plane of the vertebral body on the lateral X-ray film was measured. The ratio of anterior height of injured vertebra = (anterior height of injured vertebra / average height of upper and lower vertebrae of injured vertebra) × 100%. The anterior height of injured vertebral body was recorded before operation, 3 days after operation and the last follow-up. The angle between the extension line of upper and lower endplates of the median sagittal plane of vertebral body on lateral X-ray film was measured. The wedge angle of injured vertebral body was recorded before operation, 3 days after operation and the last follow-up. The encroachment ratio of injured vertebral canal was calculated according to the axial image of the injured vertebra on plain CT scan. The encroachment ratio = the maximum value of the bone cortex protruding into the spinal canal at the posterior edge of the vertebral body / sagittal diameter of the spinal canal × 100%. The encroachment ratio of injured vertebral canal was recorded before and 3 days after operation. JOA score was used to evaluate the improvement of spinal function. JOA score was evaluated from subjective symptoms, clinical signs, limitation of daily activities and bladder function. From 0 to 29 points, the lower the score, the more obvious the dysfunction. JOA scores were recorded before operation, 3 days after operation and the last follow-up.
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 first, 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.