Clinical efficacy of Bone Cement-injectable Cannulated Pedicle Screw Short Segment Fixation for Lumbar Spondylolisthesis with Osteoporosise

Anatomic distribution of basivertebral foramen with a magistral form in vertebral bodies of T10~L5 and its clinical significance for extensive epidural cement leakage in cement-augmented pedicle screw fixation: a multicenter case-control study

BACKGROUND

There are no reports discussing anatomic distribution of basivertebral foramen (BVF) in the osteoporotic vertebral body, which is critical in the analysis of the risk of epidural cement leakage (ECL) after cement-augmented pedicle screw fixation (CAPSF).

METHODS

371 osteoporotic patients using 1898 cement-augmented screws were included. Preoperative computed tomography (CT) was used to determine the frequency, width, height, and depth of magistral BVF in T10~L5. Additionally, we measured the distance between BVF and the left/right borders of vertebral body as well as the distance between BVF and upper/lower endplates. Following CAPSF, the severity of ECL and the position of pedicle screws were determined by postoperative CT. Finally, significant risk factors for extensive ECL were identified through binary logistic regression analysis.

RESULTS

Of 2968 vertebral bodies ranging from T10 to L5, 801 (42.2%) had a magistral BVF. From T10 to L5, the frequency of magistral BVF appeared to gradually increase. The magistral BVF was much closer to the upper endplate and the depth accounted for about a quarter of anteroposterior diameter of vertebral body. Overall, there were 19 patients (5.1%) and 32 screws (1.7%) with extensive ECL, nine of whom had neurological symptoms. The independent risk factors for extensive ECL were the magistral BVF (OR = 8.62, P < 0.001), more volume of cement injected (OR = 1.57, P = 0.031), reduced distance from screw tip to vertebral midline (OR = 0.76, P = 0.003) and vertebral posterior wall (OR = 0.77, P < 0.001) respectively.

CONCLUSION

When planning a CAPSF procedure, it is important to consider anatomical distribution of BVF and improve screw implantation methods.

Comparison of predictive performance for cage subsidence between CT-based Hounsfield units and MRI-based vertebral bone quality score following oblique lumbar interbody fusion

OBJECTIVE

To compare the predictive performance between CT-based Hounsfield units (HU) and MRI-based vertebral bone quality (VBQ) for cage subsidence (CS) following oblique lumbar interbody fusion combined with anterolateral single-rod screw fixation (OLIF-AF).

METHODS

A retrospective study was performed on consecutive patients who underwent OLIF-AF at our institution from 2018 to 2020. CS was determined by CT according to the change in the midpoint intervertebral space height. The VBQ score and HU value were measured from preoperative MRI and CT, respectively. Then, we evaluated the predictive performance of those two parameters by comparing the receiver operating characteristic (ROC) curves.

RESULTS

The mean global and segmental VBQ scores were significantly higher in the CS group, and the mean global and segmental HU values were significantly lower in the CS group. The area under the curve (AUC) of CS prediction was higher in the operative segments' VBQ score and HU value than the measurement in the global lumbar spine. Finally, the combined segmental VBQ score and segmental HU value demonstrated the highest AUC.

CONCLUSION

Both MRI-based VBQ score and CT-based HU value can achieve accurate CS prediction. Moreover, the combination of those two measurements indicated the best predictive performance.

CLINICAL RELEVANCE STATEMENT

Both MRI-based VBQ score and CT-based HU value can be used for cage subsidence prediction, in order to take preventive measures early enough.

KEY POINTS

• Osteoporosis is a risk factor for CS, both MRI-based VBQ score and CT-based HU value are important predictors during vertebral bone quality evaluation. • The VBQ score and HU value measured in the operative segments are better predictors of CS than the measurement in the global lumbar spine. • Combined segmental VBQ score and segmental HU value achieved the best predictive performance for CS.

Second-generation bone cement-injectable cannulated pedicle screws for osteoporosis: biomechanical and finite element analyses

BACKGROUND

Biomechanical and finite element analyses were performed to investigate the efficacy of second-generation bone cement-injectable cannulated pedicle screws (CICPS) in osteoporosis.

METHODS

This study used the biomechanical test module of polyurethane to simulate osteoporotic cancellous bone. Polymethylmethacrylate (PMMA) bone cement was used to anchor the pedicle screws in the module. The specimens were divided into two groups for the mechanical tests: the experimental group (second-generation CICPS) and control group (first-generation CICPS). Safety was evaluated using maximum shear force, static bending, and dynamic bending tests. Biomechanical stability evaluations included the maximum axial pullout force and rotary torque tests. X-ray imaging and computed tomography were used to evaluate the distribution of bone cement 24 h after PMMA injection, and stress distribution at the screw fracture and screw-cement-bone interface was assessed using finite element analysis.

RESULTS

Mechanical testing revealed that the experimental group (349.8 ± 28.6 N) had a higher maximum axial pullout force than the control group (277.3 ± 8.6 N; P < 0.05). The bending moments of the experimental group (128.5 ± 9.08 N) were comparable to those of the control group (113.4 ± 20.9 N; P > 0.05). The screw-in and spin-out torques of the experimental group were higher than those of the control group (spin-in, 0.793 ± 0.015 vs. 0.577 ± 0.062 N, P < 0.01; spin-out, 0.764 ± 0.027 vs. 0.612 ± 0.049 N, P < 0.01). Bone cement was mainly distributed at the front three-fifths of the screw in both groups, but the distribution was more uniform in the experimental group than in the control group. After pullout, the bone cement was closely connected to the screw, without loosening or fragmentation. In the finite element analysis, stress on the second-generation CICPS was concentrated at the proximal screw outlet, whereas stress on the first-generation CICPS was concentrated at the screw neck, and the screw-bone cement-bone interface stress of the experimental group was smaller than that of the control group.

CONCLUSION

These findings suggest that second-generation CICPS have higher safety and stability than first-generation CICPS and may be a superior choice for the treatment of osteoporosis.

Biomechanical Analysis of Cortical Bone Trajectory Screw Versus Bone Cement Screw for Fixation in Porcine Spinal Low Bone Mass Model

STUDY DESIGN

A prospective study of in vitro animal.

OBJECTION

To compare the biomechanics of cortical bone trajectory screw (CBT) and bone cement screw (BC) in an isolated porcine spinal low bone mass model.

SUMMARY OF BACKGROUND DATA

The choice of spinal fixation in patients with osteoporosis remains controversial. Is CBT better than BC? Research on this issue is lacking.

METHODS

Ten porcine spines with 3 segments were treated with EDTA decalcification. After 8 weeks, all the models met the criteria of low bone mass. Ten specimens were randomly divided into groups, group was implanted with CBT screw (CBT group) and the other group was implanted with bone cement screw (BC group). The biomechanical material testing machine was used to compare the porcine spine activities of the two groups in flexion, extension, bending, and axial rotation, and then insertional torque, pull-out force, and anti-compression force of the 2 groups were compared. Independent sample t test was used for comparison between groups.

RESULTS

Ten 3 segments of porcine spine models with low bone mass were established, and the bone mineral density of all models was lower than 0.75 g/cm 2 . There is no difference between the CBT and BC groups in flexion, extension, bending, and axial rotation angle, P >0.05. However, there were significant differences between the 2 groups and the control group, with P ＜0.01. The 2 groups significantly differed between the insertional torque ( P =0.03) and the screw pull-out force ( P =0.021). The anti-compression forces between the 2 groups have no significant difference between the two groups ( P =0.946).

CONCLUSIONS

The insertional torque and pull-out force of the CBT were higher than those of the BC in the isolated low bone porcine spine model. The range of motion and anti-compression ability of the model was similar between the 2 fixation methods.

Is 3D-printed prosthesis stable and economic enough for anterior spinal column reconstruction after spinal tumor resection? A retrospective comparative study between 3D-printed off-the-shelf prosthesis and titanium mesh cage

OBJECT

To investigate the stability and cost-effectiveness of the three-dimensional-printed (3DP) off-the-shelf (OTS) prosthesis in the reconstruction of the anterior column of the thoracic/lumbar spine after tumor resection.

METHODS

Thirty-five patients (26 with primary malignant tumors and nine with metastatic malignant tumors) who underwent tumor resection and anterior column reconstruction between January 2014 and January 2019 were included in a single institute. Patients were divided into the 3DP OTS prosthesis (3DP) group (n = 14) and the titanium mesh cage (TMC) group (n = 21) by the type of implant. The operation time, intraoperative blood loss, hospital stay, history of radiotherapy, surgical level and total cost were collected and compared between the two groups. Mechanical complications and radiological parameters including mean vertebral height, subsidence, fixation failure(nonunion, migration, screw loosening, rod breakage) rate were recorded at preoperation, 1 week, 3 months, 6 months, 12 months after surgery then at 1 year interval or stop until the end of survival. The follow-up patients were also sent with short form-36 to assess their health-related quality of life (HRQoL) and questions about the current condition of their disease.

RESULTS

The mean overall follow-up was 24.6 months. Of the 35 patients involved, six patients died and six were lost to follow-up. The differences between the two groups in operative time, intraoperative blood loss, and hospital stay were not statistically significant (p > 0.05). The differences in fixation failure and the subsidence rate between the two groups were not statistical significant (p > 0.05). The difference of subsidence rate between the cases with and without osteoporosis, cases with and without radiotherapy was statistically significant within each group (p < 0.05). However, the difference of subsidence rate between the surgical level above or below T10 was not statistically significant (p > 0.05). The response rate of the questionnaire among the survived patients was 100% (23/23 patients). The results of the Short Form- (SF-)36 between the two groups were similar (p > 0.05). The total cost was higher in the 3DP group (p < 0.05) with its higher graft cost (p < 0.05), but the differences in internal fixation cost and other cost were not statistically significant between groups (p > 0.05).

CONCLUSION

Compared to TMC, the 3DP OTS prosthesis achieved similar clinical and radiological results in spinal anterior spinal column reconstruction of thoracic/lumbar spinal tumor resection. However, the 3DP OTS prosthesis was more expansive than TMC.

Clinical evaluation of the efficacy of a new bone cement-injectable cannulated pedicle screw in the treatment of spondylolysis-type lumbar spondylolisthesis with osteoporosis: a retrospective study

Purpose

To investigate the clinical efficacy and safety of a bone cement-injectable cannulated pedicle screw (CICPS) in the treatment of spondylolysis-type lumbar spondylolisthesis with osteoporosis.

Methods

A retrospective study was conducted on 37 patients (Dual-energy X-ray bone density detection showed different degrees of osteoporosis) with spondylolysis-type lumbar spondylolisthesis who underwent lumbar spondylolisthesis reduction and fusion using a new type of injectable bone cement screw from May 2011 to March 2015. Postoperative clinical efficacy was evaluated by the Visual Analogue Scale (VAS) scores and the Oswestry Disability Index (ODI). Imaging indexes were used to evaluate the stability of internal fixation of the devices 1, 3, 6, and 12 months after surgery and annually thereafter. The safety of the CICPS was assessed by the prevalence of intraoperative and postoperative complications.

Results

A total of 124 CICPS were implanted intraoperatively. Bone cement leakage occurred in 3 screws (2.42%), and no clinical discomfort was found in any patients. All 37 patients were followed up with an average follow-up time of 26.6 ± 13.4 months (12–58 months). In the evaluation of the clinical effects of the operation, the average postoperative VAS score of the patients decreased from 4.30 ± 1.58 before surgery to 0.30 ± 0.70 after surgery (P < 0.001), and the ODI decreased from 47.27% ± 16.97% before surgery to 3.36% ± 5.70% after surgery (P < 0.001). No screw was loose, broken or pulled out.

Conclusion

CICPS is safe and effective in the treatment of spondylolysis-type lumbar spondylolisthesis complicated by osteoporosis.

Biomechanical Comparison and Three-Dimensional Analysis of Cement Distribution Patterns for Different Pedicle Screw Designs

The purpose of this study to explore strategies for reducing cement leakage during cement-augmented pedicle screw fixation, we compared the cement distribution patterns and biomechanical strengths of different types of cement-augmented fenestrated screws and traditional cement-augmented techniques. We compared five screw groups in this study: (1) Cannulated screws (Cann); (2) distal one-hole screws (D1); (3) distal two-hole screws (D2); (4) middle two-hole screws (M2); and (5) traditional screws with a traditional cement injection technique (Trad). The screws were inserted into cancellous bone blocks using a controlled, adequate cement injection pressure (1.6–2.0 kg), and an appropriate cement viscosity. Center to screw tip distance, three-dimensional distribution, and pull-out strength for cement were compared between groups. The average distance between the cement center and the screw tip was highest in the M2 group, suggesting a higher risk of cement leakage into the spinal canal. The Trad group had the highest migration distance in the z-axis, also reflecting a higher risk of leakage into the spinal canal. The D1 group had the highest pull-out strength ( $253\pm 48.82\text{N}$ and $797\pm 58.31\text{N}$ ) in bone blocks representing different degrees of osteoporosis, and the D2 group had the second highest pull-out strength in the severe osteoporosis model. Overall, D1 screws appeared to be the best option for optimizing biomechanical function and minimizing the risk of cement leakage into the spinal canal in patients with osteoporotic bone undergoing spinal surgery.

Does reduction of the Meyerding grade correlate with outcomes in patients undergoing decompression and fusion for grade I degenerative lumbar spondylolisthesis?

OBJECTIVE

Reduction of Meyerding grade is often performed during fusion for spondylolisthesis. Although radiographic appearance may improve, correlation with patient-reported outcomes (PROs) is rarely reported. In this study, the authors' aim was to assess the impact of spondylolisthesis reduction on 24-month PRO measures after decompression and fusion surgery for Meyerding grade I degenerative lumbar spondylolisthesis.

METHODS

The Quality Outcomes Database (QOD) was queried for patients undergoing posterior lumbar fusion for spondylolisthesis with a minimum 24-month follow-up, and quantitative correlation between Meyerding slippage reduction and PROs was performed. Baseline and 24-month PROs, including the Oswestry Disability Index (ODI), EQ-5D, Numeric Rating Scale (NRS)-back pain (NRS-BP), NRS-leg pain (NRS-LP), and satisfaction (North American Spine Society patient satisfaction questionnaire) scores were noted. Multivariable regression models were fitted for 24-month PROs and complications after adjusting for an array of preoperative and surgical variables. Data were analyzed for magnitude of slippage reduction and correlated with PROs. Patients were divided into two groups: < 3 mm reduction and ≥ 3 mm reduction.

RESULTS

Of 608 patients from 12 participating sites, 206 patients with complete data were identified in the QOD and included in this study. Baseline patient demographics, comorbidities, and clinical characteristics were similarly distributed between the cohorts except for depression, listhesis magnitude, and the proportion with dynamic listhesis (which were accounted for in the multivariable analysis). One hundred four (50.5%) patients underwent lumbar decompression and fusion with slippage reduction ≥ 3 mm (mean 5.19, range 3 to 11), and 102 (49.5%) patients underwent lumbar decompression and fusion with slippage reduction < 3 mm (mean 0.41, range 2 to -2). Patients in both groups (slippage reduction ≥ 3 mm, and slippage reduction < 3 mm) reported significant improvement in all primary patient reported outcomes (all p < 0.001). There was no significant difference with regard to the PROs between patients with or without intraoperative reduction of listhesis on univariate and multivariable analyses (ODI, EQ-5D, NRS-BP, NRS-LP, or satisfaction). There was no significant difference in complications between cohorts.

CONCLUSIONS

Significant improvement was found in terms of all PROs in patients undergoing decompression and fusion for lumbar spondylolisthesis. There was no correlation with clinical outcomes and magnitude of Meyerding slippage reduction.

The study of distance changes between lumbar bi-cortical pedicle screws and anterior large vessels in patients with lumbar spondylolisthesis

OBJECTIVE

This paper was a anatomical radiographic study of distance between lumbar bi-cortical pedicle screws (BPSs) and anterior large vessels (ALVs) in patients with lumbar spondylolisthesis, and to provide clinical basis for evaluating the safety of bi-cortical pedicle screw implantation during lumbar spondylolisthesis.

METHODS

Complete Computed tomography (CT) data of 104 patients with grade I lumbar spondylolisthesis (L4 52 and L5 52) and 107 non-spondylolisthesis patients (control group) were collected in this study. The distances between lumbar 4,5(L4,5) and sacrum 1(S1) BPSs and ALVs (abdominal aorta, inferior vena cava, left and right common iliac artery, internal and external iliac artery) were respectively measured at different transverse screw angles (TSAs) (L4:5°,10°; L5:10°,15°; S1:0°,5°,10°) and analyzed by SPSS (v25.0). There were three types of distances from the anterior vertebral cortex (AVC) to the ALVs (D_AVC-ALV): D_AVC-ALV N, D_AVC-ALV ≥ 0.50 cm, and D_AVC-ALV < 0.50 cm; these different distances represented non-contact, distant and close ALV respectively.

RESULTS

We calculated the incidences of screw tip contacting large vessels at different TSAs and provided the appropriate angle of screw implantation. In non-spondylolisthesis group, in L4, the appropriate left TSA was 5°, and the incidence of the close ALV was 4.62%. In S1, the appropriate left TSA was 0° and the incidence of the close ALV was 22.4%, while the appropriate right TSA was 10° and the incidence of the close ALV was 17.8%. In L4 spondylolisthesis group, in L4, the appropriate left TSA was 5°, and the incidence of the close ALV was 3.8%. In L5 spondylolisthesis group, in S1, the appropriate left TSA was 0° and the incidence of the close ALV was 19.2%, while the appropriate right TSA was 10° and the incidence of the close ALV was 21.2%. The use of BPS was not appropriate on the right side of L4 or on the either side of L5 both in spondylolisthesis and control group. In patients with lumbar 4 spondylolisthesis, the incidences of screw tip contacting large vessels were less than the control group in both L4 and 5. In patients with lumbar 5 spondylolisthesis, the incidences of screw tip contacting large vessels were less than the control group in L5, while there were no significant difference in S1.

CONCLUSION

It is very important that considering the anatomical relationship between the AVC and the ALVs while planning BPSs. The use of BPS does not apply to every lumbar vertebra. In patients with lumbar spondylolisthesis and non-spondylolisthesis patients, the incidences of screw tip contacting large vessels are different.

Outcomes of the use of cement-augmented cannulated pedicle screws in lumbar spinal fusion

BACKGROUND CONTEXT

There are few studies of the radio-clinical outcomes of cement-augmented cannulated pedicle screw (CPS) fixation in osteoporotic patients.

PURPOSE

To compare the radiological and clinical outcomes between groups receiving cement-augmented CPS and solid pedicle screws (SPS) in lumbar fusion surgery.

STUDY DESIGN/SETTING

Retrospective comparative study PATIENT SAMPLE: A total of 187 patients who underwent lumbar fusion surgery for degenerative spinal stenosis or spondylolisthesis from 2014 to 2019.

OUTCOME MEASURES

Radiological evaluation included screw failure, cage failure, rod breakage, and fusion grade at postoperative 6 months and 1 year. Pre- and postoperative visual analog scales for back pain (VAS-BP), leg pain (VAS-LP), Korean Oswestry disability index (K-ODI), and postoperative complications were also compared.

METHODS

Outcomes of patients with high risk factors for implant failure [old age, osteoporosis, autoimmune disease or chronic kidney disease (CKD)] who underwent open transforaminal lumbar interbody fusion with cement-augmented CPS fixation (Group C, n=55) or SPS fixation (Group S, n=132) were compared.

RESULTS

324 pedicle screws in Group C and 775 pedicle screws in Group S were analyzed. Group C had a significantly higher average age and lower T-score, and included more patients with autoimmune disease and CKD than group S (all p<.05). Clear zones, screw migration and loss of correction were significantly less frequent in Group C (all p<.05). Thirteen screw breakages were observed; they were only in Group C (4.0%) and all were in the proximal of the two holes. Interbody and posterolateral fusion rates were not significantly different. At last follow-up, all clinical parameters including VAS-BP, VAS-LP, and K-ODI scores had improved significantly in both groups. Postoperative complications were not significantly different in the two groups.

CONCLUSION

In lumbar fusion surgery, using cement-augmented CPS in high-risk groups for implant failure could be a useful technical option for reducing acute radiological complications and obtaining clinical results comparable to those obtained using SPS in patients with low risk of implant failure.

LEVEL OF EVIDENCE

Level 4.

Special Considerations to Improve Clinical Outcomes in Patients with Osteoporosis Undergoing Spine Surgery

BACKGROUND

Osteoporosis is a condition that is commonly encountered, with increasing diagnosis by the medical community with the aging population. Osteoporosis leaves patients susceptible to fragility fractures in the vertebrae and is also associated with degenerative changes, both of which may require intervention from a spine surgeon. The goal of this review is to concisely outline special nonoperative adjuncts, as well as preoperative, intraoperative, and postoperative considerations of osteoporotic patients undergoing spine intervention.

METHODS

A literature analysis was completed for this narrative review. A database search of PubMed and Google Scholar was conducted using "osteoporosis" combined with "spine," "spine surgery," and "spinal fusion" without exclusion based on publication date. Articles were screened to exclude duplicate articles and screened for their full text and English language availability.

RESULTS

The database search yielded recent publications from which the narrative review was completed.

CONCLUSIONS

Preoperatively, screening is traditionally completed with dual-energy x-ray absorptiometry (DEXA). Pharmacological therapy modalities currently include teriparatide, raloxifene, denosumab, bisphosphonates, and calcitonin. In order to prevent operative complications associated with osteoporosis, surgeons have found success in increasing the diameter and the length of pedicle screws, limiting pedicle tapping, achieving bicortical or even tricortical purchase, augmenting with polymethyl methacrylate, using iliosacral stabilization, preventing positive sagittal balance, and using adequate fusion products when necessary. Postoperatively, it is important to implant a care plan that includes adequate pain control and necessary care, and to understand risks associated with falls may increase risk of postoperative fragility fractures as well as instrumentation displacement. At this time there are no recommendations in regard to bracing in the postoperative setting.

CLINICAL RELEVANCE

This review article outlines the most current evidence-based medicine with regard to considerations in spine surgery of the osteoporotic patient, and aims to bring about new questions to be investigated in that paradigm.

End-To-End Computerized Diagnosis of Spondylolisthesis Using Only Lumbar X-rays

Lumbar spondylolisthesis (LS) is the anterior shift of one of the lower vertebrae about the subjacent vertebrae. There are several symptoms to define LS, and these symptoms are not detected in the early stages of LS. This leads to disease progress further without being identified. Thus, advanced treatment mechanisms are required to implement for diagnosing LS, which is crucial in terms of early diagnosis, rehabilitation, and treatment planning. Herein, a transfer learning-based CNN model is developed that uses only lumbar X-rays. The model was trained with 1922 images, and 187 images were used for validation. Later, the model was tested with 598 images. During training, the model extracts the region of interests (ROIs) via Yolov3, and then the ROIs are split into training and validation sets. Later, the ROIs are fed into the fine-tuned MobileNet CNN to accomplish the training. However, during testing, the images enter the model, and then they are classified as spondylolisthesis or normal. The end-to-end transfer learning-based CNN model reached the test accuracy of 99%, whereas the test sensitivity was 98% and the test specificity 99%. The performance results are encouraging and state that the model can be used in outpatient clinics where any experts are not present.

[Treatment of chronic thoracolumbar osteoporotic fractures combined with kyphosis with cement-injectable cannulated pedicle screw and multiple level Schwab grade osteotomy]

OBJECTIVE

To evaluate the effectiveness of cement-injectable cannulated pedicle screw combined with multiple level Schwab grade Ⅰ osteotomy for chronic thoracolumbar osteoporotic fractures with kyphosis.

METHODS

The clinical data of 27 patients with symptomatic chronic thoracolumbar osteoporotic fractures combined with kyphosis treated between June 2015 and June 2017 were retrospectively analysed. Among them, there were 8 males and 19 females, with an average age of 69.5 years (range, 56-81 years). The damage segment (kyphosis vertex) included T 11 in 4 cases, T 12 in 12 cases, L 1 in 10 cases, and L 2 in 1 case. The disease duration ranged from 3 to 21 months, with an average of 12.5 months. The T value of lumbar vertebral bone mineral density ranged from -4.9 to -2.5, with an average value of -3.61. The American Spinal Injury Association (ASIA) classification was used to evaluate spinal cord injury, there were 1 case of grade D and 26 cases of grade E. The visual analogue scale (VAS) score, Oswestry disability index (ODI), kyphosis Cobb angle of fracture site, and sagittal vertical axis (SVA) data were obtained before operation, at 2 weeks after operation, 3 months after operation, and last follow-up, to evaluate the quality of life and improvement of sagittal spine parameters.

RESULTS

No complications related to pedicle screw and bone cement occurred. The incisions healed by first intention in 26 cases, and 1 incision healed after dressing change due to poor blood glucose control. There were no complications such as bedsore, hypostatic pneumonia, or deep venous thrombosis. All patients were followed up 8-24 months, with an average of 16.6 months. The VAS score, ODI score, Cobb angle, and SVA were significantly improved when compared with those before operation ( P<0.05). There was no significant difference in Cobb angle between each time point after operation ( P>0.05); the VAS score and ODI score at 3 months after operation and last follow-up were significantly better than those at 2 weeks after operation ( P<0.05), and the ODI score at last follow-up was further improved when compared with the score at 3 months ( P<0.05), but there was no significant difference in VAS score ( P>0.05); SVA at last follow-up was significantly worse than that at 2 weeks and 3 months after operation ( P<0.05), but there was no significant difference between at 2 weeks and 3 months after operation ( P>0.05). During the follow-up period, there was no complication such as pedicle screw loosening, breakage or cutting, adjacent vertebral fracture, proximal junctional kyphosis, and so on.

CONCLUSION

For the chronic thoracolumbar osteoporotic fractures combined with kyphosis, the cement-injectable cannulated pedicle screw and multiple level Schwab grade Ⅰ osteotomy has the advantages of less operation trauma, quick recovery, and remarkable effectiveness.

Factors Impacting Outcomes and Health Care Utilization in Osteoporotic Patients Undergoing Lumbar Spine Fusions: A MarketScan Database Analysis

OBJECTIVE

To identify factors impacting long-term complications, reoperations, readmission rates, and health care utilization in patients with osteoporosis (OP) following lumbar fusions.

METHODS

We used International Classification of Disease, Ninth Revision, International Classification of Disease, Tenth Revision , and Current Procedural Terminology codes to extract data from MarketScan (2000-2016). Patients undergoing lumbar spine fusion were divided into 2 groups based on preoperative diagnosis: OP or non-OP. We used multivariable generalized linear regression models to analyze outcomes of interest (reoperation rates, readmissions, complications, health care utilization) at 1, 6, 12, and 24 months after discharge.

RESULTS

MarketScan identified 116,749 patients who underwent lumbar fusion with ≥24 months of follow-up; 6% had OP. OP patients had a higher incidence of complications (14% vs. 9%); were less likely to be discharged home (77% vs. 86%, P < 0.05); had more new fusions or refusions at 6 months (2.9% vs. 2.1%), 12 months (5% vs. 3.8%), and 24 months (8.5% vs. 7.4%); incurred more outpatient services at 12 months (80 vs. 61) and 24 months (148 vs. 115); and incurred higher overall costs at 12 months ($22,932 vs. $17,017) and 24 months ($48,379 vs. $35,888). Elderly OP patients (>65 years old) who underwent multilevel lumbar fusions had longer hospitalization, had higher complication rates, and incurred lower costs at 6, 12, and 24 months compared with young non-OP patients who underwent single-level lumbar fusion.

CONCLUSIONS

Patients of all ages with OP had higher complication rates and required revision surgeries at 6, 12, and 24 months compared with non-OP patients. Elderly OP patients having multilevel lumbar fusions were twice as likely to have complications and lower health care utilization compared with younger non-OP patients who underwent single-level fusion.