Comparison of the short-segment and long-segment cement-augmented pedicle screw fixation for osteoporotic thoracolumbar fracture: A finite element study / 中国组织工程研究

BACKGROUND: Pedicle screw fixation combined with cement-augmented is an effective method for the treatment of severe osteoporotic vertebral fractures, but there is no uniform standard. The range of fixed segments is one of the focus of clinical controversy. OBJECTIVE: To establish a three-dimensional finite element model of the short-segment and long-segment cement-augmented pedicle screw fixation for osteoporotic thoracolumbar fracture, and to analyze the biomechanical characteristics of adjacent segment structures, fractured vertebral bodies and internal fixation devices. METHODS: The T 9 -L 5 segment of a volunteer without obvious degenerative disease was selected for CT scan. The CT images of Dicom format were obtained, and the engineering software was imported to establish a finite element geometric model to simulate the thoracolumbar fracture and the short-segment and long-segment cement-augmented pedicle screw fixation models. The relevant material parameters were set and the biomechanical characteristics of the two groups were compared and analyzed. RESULTS AND CONCLUSION: (1) The stress on the vertebrae was mainly concentrated on the periphery of the vertebral body and the small facet of the attachment. In the four directions flexion, extension, left-sided and right-sided curvature, the maximum stress of the proximal and distal adjacent vertebrae in the long-segment group was greater than that in the short-segment group. The stress of the intervertebral disc was mainly concentrated in the peripheral annulus. The maximum stress of the proximal and distal adjacent intervertebral discs was greater in the short -segment than in the long-segment, but the high stress area of the long-segment was larger than that of the short-segment. Therefore, long-segment fixation might accelerate the degeneration of adjacent segments.(2) The vertebral bodies of the long-segment group and the short-segment group were displaced to different extents, and the displacements in the left and right directions were the most obvious. In the six movement directions, the displacement and maximum stress of the injured segment of the short-segment group were greater than those of the long-segment group. So the long-segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short- segment group.and the displacements in the left and right directions were the most obvious. In the six movement directions, the displacement and maximum stress of the injured segment of the short-segment group were greater than those of the long-segment group. So the long- segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group.and the displacements in the left and right directions were the most obvious. In the six movement directions, the displacement and maximum stress of the injured segment of the short-segment group were greater than those of the long-segment group. So the long- segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group.So the long-segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group. So the long-segment fixation could better maintain the stability of the fractured vertebra. (3) The stress on the internal fixing device was mainly concentrated on the screws at both ends and the part of the rod. The maximum stress of the long-segment group was greater than that of the short-segment group, but the main stress area of the screws at both ends was smaller compared with the short-segment group.

Factors affecting Sandwich vertebral re-fracture after vertebral augmentation surgery for osteoporotic spine Sandwich fractures / 中华创伤杂志

Objective To investigate the risk factors affecting Sandwich vertebral re-fracture after vertebral augmentation surgery for osteoporotic spine Sandwich fractures.Methods A retrospective case control study was conducted on the clinical data of 90 patients with osteoporotic spine Sandwich fractures treated with vertebral augmentation surgery from January 2004 to December 2015.There were 26 males and 64 females,aged (69.9 ± 7.4) years.The patients were divided into fracture group (n =15) and non fracture group (n =75) according to the incidence of re-fracture after operation during follow-up.Gender,age,height,weight,bone mineral density,cumulative number of cemented vertebrae,location of the Sandwich vertebrae in the thoracolumbar segment,the preoperative kyphosis angle of the Sandwich fracture segment,surgical approach,cement injection approach (unilateral or bilateral),cement injection volume,cement leakage between the Sandwich intervertebral spaces,the postoperative kyphosis angle of the Sandwich fracture segment,and follow-up duration were used as independent variables.Chi-square test and multivariate logistic regression analysis were used to analyze the risk factors of vertebral Sandwich fracture.Results There were 97 Sandwich vertebrae in 90 patients,and 226 fractured vertebrae were treated with initial intensive treatment.The mean follow-up was 18.1 months.There were no significant differences in gender,age,height,weight,cumulative number of cemented vertebrae,whether the Sandwich vertebrae was located at the thoracolumbar segment,the preoperative kyphosis angle of the Sandwich fracture segment,the cement injection approach (unilateral or bilateral),the volume of cement injection,and the cement leakage between the Sandwich intervertebral spaces (P ＞ 0.05).There were significant differences in bone mineral density,surgical approach,and postoperative kyphosis angle of the Sandwich fracture segment between the two groups (P ＜ 0.05).Further logistic regression analysis showed that bone mineral density ≤ 3.5 SD and segmental kyphosis (≥ 10°) were risk factors for Sandwich fracture (P ＜ 0.05).Conclusions The low bone mineral density (T value ≤-3.5 SD) and postoperative kyphotic angle (≥ 10°) are risk factors for re-fracture of Sandwich vertebrae.Vertebroplasty itself does not increase the risk of recurrent vertebral fractures.

Posterior Screw Fixation in Previously Augmented Vertebrae with Bone Cement: Is It Inapplicable?

OBJECTIVE: The purpose of this study was to determine the feasibility of screw fixation in previously augmented vertebrae with bone cement. We also investigated the influence of cement distribution pattern on the surgical technique.METHODS: Fourteen patients who required screw fixation at the level of the previous percutaneous vertebroplasty or balloon kyphoplasty were enrolled in this study. The indications for screw fixation in the previously augmented vertebrae with bone cement included delayed complications, such as cement dislodgement, cement leakage with neurologic deficits, and various degenerative spinal diseases, such as spondylolisthesis or foraminal stenosis. Clinical outcomes, including pain scale scores, cement distribution pattern, and procedure-related complications were assessed.RESULTS: Three patients underwent posterior screw fixation in previously cemented vertebrae due to cement dislodgement or progressive kyphosis. Three patients required posterior screw fixation for cement leakage or displacement of fracture fragments with neurologic deficits. Eight patients underwent posterior screw fixation due to various degenerative spinal diseases. It was possible to insert screws in the previously augmented vertebrae regardless of the cement distribution pattern; however, screw insertion was more difficult and changed directions in the patients with cemented vertebrae exhibiting a solid pattern rather than a trabecular pattern. All patients showed significant improvements in pain compared with the preoperative levels, and no patient experienced neurologic deterioration as seen at the final follow-up.CONCLUSION: For patients with vertebrae previously augmented with bone cement, posterior screw fixation is not a contraindication, but is a feasible option.

Posterior Screw Fixation in Previously Augmented Vertebrae with Bone Cement: Is It Inapplicable?

OBJECTIVE: The purpose of this study was to determine the feasibility of screw fixation in previously augmented vertebrae with bone cement. We also investigated the influence of cement distribution pattern on the surgical technique. METHODS: Fourteen patients who required screw fixation at the level of the previous percutaneous vertebroplasty or balloon kyphoplasty were enrolled in this study. The indications for screw fixation in the previously augmented vertebrae with bone cement included delayed complications, such as cement dislodgement, cement leakage with neurologic deficits, and various degenerative spinal diseases, such as spondylolisthesis or foraminal stenosis. Clinical outcomes, including pain scale scores, cement distribution pattern, and procedure-related complications were assessed. RESULTS: Three patients underwent posterior screw fixation in previously cemented vertebrae due to cement dislodgement or progressive kyphosis. Three patients required posterior screw fixation for cement leakage or displacement of fracture fragments with neurologic deficits. Eight patients underwent posterior screw fixation due to various degenerative spinal diseases. It was possible to insert screws in the previously augmented vertebrae regardless of the cement distribution pattern; however, screw insertion was more difficult and changed directions in the patients with cemented vertebrae exhibiting a solid pattern rather than a trabecular pattern. All patients showed significant improvements in pain compared with the preoperative levels, and no patient experienced neurologic deterioration as seen at the final follow-up. CONCLUSION: For patients with vertebrae previously augmented with bone cement, posterior screw fixation is not a contraindication, but is a feasible option.

Clinical Efficacy and Safety of Radiofrequency Ablation Therapy with Cement Augmentation for a Metastatic Spine Tumor

STUDY DESIGN: Retrospective study. OBJECTIVES: To evaluate the clinical efficacy and safety of radiofrequency (RF) ablation therapy followed by a bone cement augmentation procedure in treating and managing pain among metastatic spine tumor patients. SUMMARY OF LITERATURE REVIEW: As a metastatic spine tumor is unresectable, this procedure was performed. Results showed an increase in the necrosis rate, and a decrease in local recurrence and secondary vertebral stability. MATERIALS AND METHODS: From March 2007 to April 2016, 26 patients who were treated with RF ablation with a bone cement augmentation procedure and the same number of patients treated with radiotherapy for metastatic spine lesions were included in this study. Pain relief and functional quality of life were evaluated using a visual analogue scale (VAS) and Roland Morris Questionnaire (RMQ). RESULTS: VAS scores preoperatively and at 1, 4, and 12 weeks follow-up were 7.45, 3.01, 3.78, and 2.97 in the procedure group, and 7.04, 6.65, 5.87, and 3.03 in the radiotherapy group. The procedure group had significantly better average outcomes than the radiotherapy group for pain relief at 4 weeks but showed no difference at 12 weeks. The RMQ score improved from 13.92 to 7.21 in the procedure group, and from 15.33 to 9.75 in the radiotherapy group. Two patients who had a metastatic tumor near the vertebral body posterior cortex showed cement leakage into the disc space, that is, intraforaminal and intracanal space; therefore, operations were performed (7.69% nerve injury). CONCLUSIONS: RF ablation therapy with cement augmentation in treatment of metastatic spine tumor shows effectiveness in early pain relief and brings immediate vertebral stability, helping patients return to normal life. However, it carries a risk of nerve injury due to cement leakage.

Percutaneous Iliosacral Screw Fixation with Cement Augmentation in Sacral Insufficient Fracture: A Case Report / 대한고관절학회지

Sacral insufficiency fractures (SIFs) are no longer a rare type of fracture in the elderly. To date, SIFs have typically been treated conservatively. Sacroplasty has recently been used in treatment of SIFs, with a good result. In order to solve the problems of sacroplasty, the authors performed a new surgical technique, percutaneous iliosacral screw fixation with cement augmentation, for SIFs. Secure fixation of the screw in osteoporotic bone was achieved and biological bone union was obtained. We present this case with a review of the literature.

Retrograde Intramedullary Nailing for Distal Femur Fracture with Osteoporosis

BACKGROUND: The incidence of distal femur fracture in the elderly has been increasing recently, and commonly occurs with osteoporosis. Retrograde intramedullary nailing has been considered a good surgical option for distal femur fracture. The purpose of the present study was to present our surgical results with retrograde intramedullary nailing for distal femur fractures with osteoporosis. METHODS: Thirteen patients diagnosed with extra-articular distal femur fracture and osteoporosis and managed with retrograde intramedullary nailing were retrospectively reviewed. Cement augmentation was used in four patients, shape memory alloy was used in eight patients and both were used in one patient. All patients were followed up for more than 2 years. Radiologic alignments. were scored and Tegner and the Lysholm activity score was used for a functional assessment. RESULTS: The average time to clinical union was 13 weeks (range, 10 to 15 weeks). In 12 of our cases, the total alignment scores were excellent. At the last follow-up, the mean range of motion was 116degrees (range, 110degrees to 125degrees). The average functional score at postoperative 1 year was 2.6 (range, 1 to 5). CONCLUSIONS: Retrograde intramedullary nailing is a good surgical option for distal femur fracture with osteoporosis. Cement augmentation and shape memory alloy can also be used for added mechanical stability. This surgical technique is very useful for distal femur fracture with osteoporosis as it promotes fracture healing and early rehabilitation.

Effect of Bone Cement Augmentation of Pedicular Screwing for Osteoporotic Lumbar Spine / 대한척추외과학회지

STUDY DESIGN: Eighteen patients undergoing bone cement augmentation of pedicular screwing for osteoporotic lumbar spine were reviewed retropectively. OBJECTIVES: To assess the effectiveness of bone cement augmentation of pedicular screwing for osteoporotic lumbar spine. SUMMARY OF LITERATURE REVIEW: For the technical limit obtaining the dynamic stability in the bone-screw interface for osteoporotic lumbar spine, the additional device to enhance pedicular screw fixation strength needs. MATERIALS AND METHODS: We reviewed 18 cases undergoing pedicular screwing and fusion for the osteoporotic (Jikei grade I, II, III/III) lumbar spine from Feb. 2000 to Mar. 2001 with an average follow-up of 1.5 years. Mean age was 69.5 years with 6 male and 12 female. Inclusion criteria was 9 degenerative spinal stenosis, 5 spinal stenosis associated with compression fracture, 2 Kummel's disease, 1 spondylolisthesis and 1 internal disc disruption. We performed bone cement injection around the screws showing significantly low insertion torque, screw pullout or cut-up during surgery. We asssessed the radiographic results of sagittal angle correction (SAC) of the fused segment and disc height restoration (DHR) on the preoperative, postoperative and last follow up lumbar lateral views. Clinical results were evaluated according to the Kumano's criteria. RESULTS: Mean sagittal angle at preoperative, postoperative and last follow-up was 11.6-21.6-19.6 degrees with mean SAC gain 10 degrees (p0.05). Mean disc height of each period was 33.3-49.8-43.5% with mean DHR gain 16.5% (p0.05). The clinical result was analyzed as 14 good, 3 fair and 1 poor. Fusion success was achieved in all. There were 2 perioperative complications of 1 superficial surgical site infection and 1 incomplete L4 root injury, and 6 complications during follow up of 3 compression fractures above fused segment, 1 screw pullout, 1 screw cut-up, and 1 bone cement extrava-sation into canal. CONCLUSIONS: The bone cement augmentation of pedicular screwing for osteoporotic lumbar spine can be an alternative to enhance screw fixation strength.