Objective To investigate the effectiveness and long-term stability of small fenestration vertebral bone grafting and transpedicular bone grafting in the treatment of Denis types A and B thoracolumbar burst fractures. Methods Between January 2012 and February 2014, 50 patients with Denis type A or B thoracolumbar burst fractures were treated with vertebroplasty and pedicle screw rod fixation system, and the clinical data were retrospectively analyzed. Small fenestration vertebral bone grafting by trans-interlaminar approach was used in 30 cases (group A), and bone grafting by unilateral transpedicular approach was used in 20 cases (group B). X-ray and CT examinations of the thoracolumbar vertebrae were performed routinely before and after operation. There was no significant difference in sex, age, cause of injury, time from injury to operation, fracture type, injury segment, and preoperative Frankel classification, the percentage of the anterior body height of the injured vertebra, and visual analogue scale (VAS) score between two groups (P>0.05). There was significant difference in preoperative Cobb angle of kyphosis between two groups (P<0.05). The Cobb angle of kyphosis, the percentage of the anterior body height of the injured vertebra, and the recovery of neurological function were recorded and compared between two groups. Results The patients were followed up for 16-31 months (mean, 19.1 months) in group A and for 17-25 months (mean, 20.2 months) in group B. Primary healing of incisions was obtained in the two groups; no nerve injury and other operative complications occurred. The neurological function was improved in varying degrees in the other patients with neurological impairment before operation except patients at grade A of Frankel classification. The lumbar back pain was relieved in two groups. There was significant difference in VAS score between before operation and at 3 months after operation or last follow-up in two groups (P<0.05), but no significant difference was found between at 3 months and last follow-up in two groups and between two groups at each time point after operation (P>0.05). X-ray examination showed that there was no breakage of nail and bar, or dislocation and loosening of internal fixation during follow-up period. The bone grafts filled well and fused in the fractured vertebra. The vertebral height recovered well after operation. The percentage of the anterior body height of the in-jured vertebra and Cobb angle of kyphosis at 1 week, 3 months, and last follow-up were significantly better than preope-rative ones in two groups (P<0.05), but there was no significant difference between different time points after operation (P>0.05), and between two groups at each time point after operation (P>0.05). Conclusion For Denis types A and B thoracolumbar burst fractures, vertebral bone grafting and pedicle screw internal fixation through interlaminal small fene-stration or transpedicular approach can restore the vertebral height, correct kyphosis, and maintain the vertebral stability, which reduce the risk of complications of loosening and breakage of internal fixators. The appropriate bone grafting approach can be chosen based on the degree of spinal canal space occupying, collapse of vertebral and spinal cord injury.
Objective To investigate the amount of bone grafting, bone defect gap residual rates, and biomechanical stability of the injured vertebral body after reduction of thoracolumbar burst fractures, pedicle screw-rods fixation, and bone graft by bilateral pedicle or unilateral spinal canal. Methods Eighteen fresh lumbar spine (L1-5) specimens of calves (aged 4-6 months) were collected to establish the burst fracture model at L3 and divided into 3 groups randomly. After reduction and fixation with pedicle screws, no bone graft was given in group A (n=6), and bone graft was performed by bilateral pedicles in group B (n=6) and by unilateral spinal canal in group C (n=6). The amount of bone grafting in groups B and C was recorded. The general situation of bone defect gaps was observed by the DR films and CT scanning, and the defect gap residual rates of the injured vertebrae were calculated with counting of grids. The compression stiffness was measured by ElectreForce-3510 high precision biological material testing machines. Results The amount of bone grafting was (4.58 ± 0.66) g and (5.72 ± 0.78) g in groups B and C respectively, showing signficant difference (t=2.707, P=0.022). DR films and CT scanning observation showed large bone defect gap was seen in injured vertebrae specimens of group A; however, the grafting bone grains was seen in the “eggshell” gap of the injured vertebral body, which were mainly located in the posterior part of the vertebral body, but insufficient filling of bone graft in the anterior part of the vertebral body in group B; better filling of the grafting bone grains was seen in injured vertebral body of group C, with uniform distribution. The bone defect gap residual rates were 52.0% ± 5.5%, 39.7% ± 2.5%, and 19.5% ± 2.5% respectively in groups A, B, and C; group C was significantly lower than groups A and B (P lt; 0.05), and group B was significantly lower than group A (P lt; 0.05). Flexion compressive stiffness of group C was significantly higher than that of groups A and B (P lt; 0.05), but no significant difference was found between groups A and B (P gt; 0.05). Extension compressive stiffness in group C was significantly higher than that in group A (P lt; 0.05), but no significant difference was found between groups A and B, and between groups B and C (P gt; 0.05). The compression stiffness of left bending and right bending had no significant difference among 3 groups (P gt; 0.05). Conclusion Thoracolumbar burst fracture pedicle screws fixation with bone grafting by unilateral spinal canal can implant more bone grains, has smaller bone defect gap residual rate, and better recovery of flexion compression stiffness than by bilateral pedicles.
ObjectiveTo investigate the effectiveness of posterior microscopic mini-open technique (MOT) decompression in patients with severe spinal canal stenosis resulting from thoracolumbar burst fractures.MethodsThe clinical data of 28 patients with severe spinal canal stenosis caused by thoracolumbar burst fractures, who were treated by posterior microscopic MOT, which performed unilateral or bilateral laminectomy, poking reduction, intervertebral bone graft via spinal canal, and percutaneous pedicle screw fixation between January 2014 and January 2016 were retrospectively analyzed. There were 21 males and 7 females with a mean age of 42.1 years (range, 16-61 years). The involved segments included T11 in 1 case, T12 in 4 cases, L1 in 14 cases, and L2 in 9 cases. According to AO classification, there were 19 cases of type A3, 9 of type A4. According to American Spinal Injury Association (ASIA) grading, 12 cases were grade C, 13 grade D, and 3 grade E. The time between injury and operation was 3-7 days (mean, 3.6 days). To evaluate effectiveness, the changes in the visual analogue scale (VAS), percentage of anterior height of injured vertebrae, Cobb angle, rate of spinal compromise (RSC), and ASIA grading were analyzed.ResultsAll patients were performed procedures successfully. The operation time was 135-323 minutes (mean, 216.4 minutes). The intraoperative blood loss was 80-800 mL (mean, 197.7 mL). The hospitalization time was 10-25 days (mean, 12.5 days). The incisions healed primarily, without wound infection, cerebrospinal fluid leakage, or other early complications. All the 28 patients were followed up 12-24 months (mean, 16.5 months). No breakage or loosening of internal fixation occurred. All fractures healed, and the healing time was 3-12 months (mean, 6.5 months). Compared with preoperative ones, the percentage of anterior height of injured vertebrae, Cobb angle, and RSC at immediate after operation and at last follow-up and the VAS scores at 1 day after operation and at last-follow were significantly improved (P<0.05). There was no significant difference in the percentage of anterior height of injured vertebrae and Cobb angle between at immediate after operation and at last follow-up (P>0.05). But the RSC at immediate after operation and VSA score at 1 day after operation were significantly improved when compared with those at last follow-up (P<0.05). The ASIA grading at last follow-up was 1 case of grade C, 14 grade D, and 13 grade E, which was significantly improved when compared with preoperative ones (Z=3.860, P=0.000).ConclusionMOT is an effective and minimal invasive treatment for thoracolumbar AO type A3 and A4 burst fractures with severe spinal canal stenosis, and it is beneficial to early rehabilitation for patients.
Objective To design the surgical strategy of percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for bilateral lumbar spinal stenosis (LSS) and to evaluate the effectiveness. Methods The percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for bilateral LSS was designed according to the pathological features of LSS. The technique was used to treat 42 patients with LSS between January 2016 and January 2018. There were 18 males and 24 females with an average age of 61.7 years (range, 46-81 years). The duration of symptoms was 1-20 years, with an average of 9.7 years. The surgical segment at L4, 5 were 27 cases, at L5, S1 were 15 cases. The operation time and perioperative complications were recorded. Lumbar X-ray, CT, and MRI examinations were performed at 1 week, 3 months, and 1 year after operation. Visual analogue scale (VAS) score was used to evaluate the low back pain and leg pain, Oswestry disability index (ODI) was used to evaluate the lumbar function, and single continuous walking distance (SCWD) was used to evaluate lower extremity nerve function. The clinical efficacy was evaluated by MacNab criteria at 1 year after operation. Results All patients underwent surgery successfully. The operation time was 68-141 minutes with an average of 98.2 minutes. All 42 patients were followed up 12-24 months with an average of 18.8 months. There were 2 cases of dural tears during operation, and 1 case of transient dysfunction of the lower limbs of the decompression channel after operation. All of them were cured after corresponding treatment. No serious complications such as death, major bleeding, or irreversible nerve injury occurred during follow-up. No segmental instability was found according to postoperative lumbar hyperextension and flexion X-ray films, and postoperative CT and MRI imaging showed that the stenotic lumbar spinal canal was significantly enlarged, and the compression of the nerve root was sufficient. The VAS score of low back pain and leg pain, ODI score, and SCWD at each time point after operation were significantly improved when compared with those before operation (P<0.05); the indexes were significantly improved over time after operation, and the differences were significantly (P<0.05). The clinical efficacy was evaluated by MacNab standard at 1 year after operation, and the results were excellent in 18 cases, good in 20 cases, fair in 3 cases, and poor in 1 case. The excellent and good rate was 90.5%. Conclusion The percutaneous full-endoscopic bilateral decompression via unilateral posterior approach for LSS is a safe and effective procedure. A well-designed surgical strategy and mastery of its technical points are important guarantees for successful operation and satisfactory results.