Instability of treated vertebrae after balloon kyphoplasty causing paraparesis in osteoporotic vertebral compression fracture: a report of two cases

Prevention of Bone Cement Displacement in Kümmell Disease without Neurological Deficits through Treatment with a Novel Hollow Pedicle Screw Combined with Kyphoplasty

OBJECTIVE

Displacement of bone cement following percutaneous vertebral augmentation for Kümmell disease (KD) presents a significant concern, resulting in increasing back pain and compromising daily activities. Unfortunately, current literature does not yet establish a validated and minimally invasive surgical intervention for this issue. This study aims to investigate the effects of a novel hollow pedicle screw combined with kyphoplasty (HPS-KP) in preventing bone cement displacement following simply percutaneous kyphoplasty for the management of KD.

METHODS

A total of 22 patients (six males, 16 females, averagely aged 77.18 ± 7.63 years) with KD without neurological deficits treated by HPS-KP at the hospital between March 2021 and June 2022 were hereby selected, among which, there were three stage I KD cases, 12 stage II KD cases, and seven stage III KD cases according to Li's classification. Bone mineral density (BMD), spinal X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) were examined before the operation. The operation time, intraoperative blood loss, and postoperative complications were all recorded. The follow-up focused on visual analog scale (VAS) score, Oswestry dysfunction index (ODI), anterior vertebral height (AVH), middle vertebral height (MVH), posterior vertebral height (PVH), wedge-shape affected vertebral Cobb angle (WCA), and bisegmental Cobb angle (BCA). One-way analysis of variance (ANOVA) followed by Bonferroni post-hoc test was employed for performing multiple comparisons in the present study.

RESULTS

All patients having received the operation successfully were followed up for more than 8 months (ranging from 8 to 18 months). The operation time, intraoperative blood loss, and BMD (T-score) were 39.09 ± 5.64 min, 14.09 ± 3.98 ml, and - 3.30 ± 0.90 g/cm3 , respectively. Statistically significant differences were observed in the VAS score, ODI, AVH, MVH, and WCA (All p < 0.05), but there was no statistically significant difference in PVH and BCA at different time points (All p > 0.05). During follow-up, five patients suffered from bone cement leakage, and one presented an adjacent vertebral fracture and no bone cement displacement.

CONCLUSION

HPS-KP could be safe and effective in the treatment of KD without neurological deficits, effectively relieving the symptoms of patients, restoring partial vertebral height, and preventing the occurrence of bone cement displacement.

Osteoporotic Thoracolumbar Vertebral Fractures With Neurological Deficit Treated by Balloon Kyphoplasty Augmented with Newly Developed Minimally Invasive Posterior Hook Stabilization

Most osteoporotic vertebral fractures (OVFs) are treated conservatively, but surgery is often indicated for residual pain, neuropathy, or severe deformity. OVFs tend to develop in elderly patients, so less invasive surgery is desirable. Surgery is mainly performed to stabilize the fractured vertebral body. Percutaneous cement augmentation, such as via balloon kyphoplasty (BKP), has produced satisfactory results as a surgical method for managing OVFs. Posterior fixation with implants is often performed with or without cement augmentation when stronger fixation is considered necessary for OVFs with local kyphosis and angular instability. Pedicle screws (PSs) are widely used as an implant for posterior fixation, but given the risk of backing out in bones with severe osteoporosis, several measures have been taken to increase the strength such as by adding hooks. In cases of osteoporosis, hooks that can use cortical bone as an anchor are considered more useful than PS but are rarely used in minimally invasive surgery. We developed a minimally invasive posterior hook stabilization approach to directly stabilize the posterior spinal components as a new augmentation method for BKP and applied it to four cases of thoracolumbar OVF with neurological symptoms. The operation time was about 60 minutes, including BKP, and the estimated blood loss was about 10 ml. No postoperative implant problems occurred, and in all cases, neurological symptoms, such as buttocks and leg pain, were alleviated at an early stage after surgery. One patient had a postoperative adjacent vertebral body fracture that was conservatively treatable. Minimally invasive posterior hook stabilization, which we developed as a way of augmenting BKP, was considered useful for managing vertebral body fractures of the thoracolumbar spine with local kyphosis and angular instability.

A combined experimental and computational study of mechanical properties after balloon kyphoplasty

Vertebral compression fractures rank among the most frequent injuries to the musculoskeletal system, with more than 1 million fractures per annum worldwide. The past decade has seen a considerable increase in the utilisation of surgical procedures such as balloon kyphoplasty to treat these injuries. While many kyphoplasty studies have examined the risk of damage to adjacent vertebra after treatment, recent case reports have also emerged to indicate the potential for the treated vertebra itself to re-collapse after surgery. The following study presents a combined experimental and computational study of balloon kyphoplasty which aims to establish a methodology capable of evaluating these cases of vertebral re-collapse. Results from both the experimental tests and computational models showed significant increases in strength and stiffness after treatment, by factors ranging from 1.44 to 1.93, respectively. Fatigue tests on treated specimens showed a 37% drop in the rate of stiffness loss compared to the untreated baseline case. Further analysis of the computational models concluded that inhibited PMMA interdigitation at the interface during kyphoplasty could reverse improvements in strength and stiffness that could otherwise be gained by the treatment.

A Multiscale Finite Element Analysis of Balloon Kyphoplasty to Investigate the Risk of Bone-Cement Separation In Vivo

BACKGROUND

During the past decade there has been a significant increase in the number of vertebral fractures being treated with the balloon kyphoplasty procedure. Although previous investigations have found kyphoplasty to be an effective treatment for reducing patient pain and lowering cement-leakage risk, there have been reports of vertebral recollapse following the procedure. These reports have indicated evidence of in vivo bone-cement separation leading to collapse of the treated vertebra.

METHODS

The following study documents a multiscale analysis capable of evaluating the risk of bone-cement interface separation during lying, standing, and walking activities following balloon kyphoplasty.

RESULTS

Results from the analysis found that instances of reduced cement interlock could initiate both tensile and shear separation of the interface region at up to 7 times the failure threshold during walking or up to 1.9 times the threshold during some cases for standing. Lying prone offered the best protection from interface failure in all cases, with a minimum safety factor of 2.95.

CONCLUSIONS

The results of the multiscale analysis show it is essential for kyphoplasty simulations to take account of the micromechanical behavior of the bone-cement interface to be truly representative of the in vivo situation after the treatment. The results further illustrate the importance of ensuring adequate cement infiltration into the compacted bone periphery during kyphoplasty through a combination of new techniques, tools, and biomaterials in a multifaceted approach to solve this complex challenge.

Factors affecting postoperative mortality of patients with insufficient union following osteoporotic vertebral fractures and impact of preoperative serum albumin on mortality

Background

Numerous comparative studies of surgical procedures have focused on clinical and radiographical outcomes, as well as the effect of bone fragility on the outcome of spinal surgery; however, insights concerning a risk of mortality or morbidity have been limited. Additionally, the effect of surgical therapy on survival after vertebral compression fractures remains controversial. Our aim was to evaluate the preoperative factors that affected the long-term survival of patients who underwent spinal surgery for an insufficient union following osteoporotic vertebral fractures (OVF) and to determine postoperative mortality.

Methods

We retrospectively reviewed the cases of 105 consecutive patients who underwent spinal surgery for OVF. Mortality was estimated using the Kaplan-Meier method and a log-rank test. The preoperative backgrounds of patients were analyzed to determine which risk factors led to death among the OVF cases. Kaplan-Meier curves were used to estimate survival based on preoperative albumin levels of ≤3.5 g/dL (hypoalbuminemia) versus > 3.5 mg/dL.

Results

The mean follow-up time was 4.1 ± 0.8 years. Two years after surgery, percentage of patients who had died was 15%. The VAS scores and modified Frankel classification were significantly improved one year after surgery. The ratio of male-to-female was significantly higher for patients with OVF who died than for those who were still alive. No significant difference in mortality was observed among surgical procedures for OVF. The univariate analysis showed that male gender, serum albumin < 3.5 g/dl, creatinine clearance< 60 mg/dl, and the American Society of Anesthesiologists classificat0ion ≥3 were significant risk factors for postoperative mortality. Multivariate analysis revealed that only serum albumin ≤3.5 g/dL was a significant risk factor for long-term postoperative mortality of patients with OVF.

Conclusions

Preoperative hypoalbuminemia was associated with postoperative mortality following surgery for OVF.

Level of evidence

Level 3.

Teriparatide Associated with Fewer Refractures and Higher Body Heights of Cemented Vertebrae after Vertebroplasty: A Matched Cohort Study

Refracture of cemented vertebrae occurs commonly after vertebroplasty (VP) for osteoporotic vertebral compression fracture (OVCF). It can result in severe pain or neurological deficit, but no preventive medication is available. Owing to the bone anabolic benefits of teriparatide (TP), this study was aimed to compare the outcomes of cemented vertebrae with TP to those without TP. Patients who received VP for OVCF with at least 1 year follow-up were included. The anterior body height (ABH) and middle body height (MBH) and kyphotic angle (KA) were measured before VP and 1 week and at least 1 year after VP. Refracture was defined as a 15% decrease in ABH or MBH and 8° decrease in KA compared with those at postoperative 1 week. The clinical outcomes were evaluated. 35 VP procedures in 21 patients treated with TP (TP group), and, matched to that, 29 out of 133 patients treated with VP alone (VP group) were included. One year after VP, ABH and MBH were significantly greater, except KA, in the TP group (VP group vs. TP group: KA - 4.97° ± 12.1 vs. -2.85° ± 12.21°, p = 0.462, ABH 1.56 ± 0.48 cm vs. 1.84 ± 0.56 cm, p = 0.027, MBH 1.49 ± 0.39 cm vs. 1.73 ± 0.41 cm, p = 0.017). The refracture rates of KA, ABH, and MBH were significantly lower in the TP group (VP group vs. TP group: KA 42.11% vs.8.57%, p < 0.001; ABH 76.32% vs. 28.57%, p < 0.0001; MBH 76.32% vs. 28.57%, p < 0.0001). In single-level subgroup comparison, TP was associated with better improvement of pain VAS and better radiological outcomes. TP was associated with higher BHs and fewer refractures than VP alone, with comparable clinical outcomes 1 year after VP. TP may be associated with better improvement of pain VAS in those with single-level VP procedure. Higher BH was due to the better maintenance effect of TP.

Percutaneous kyphoplasty: Risk Factors for Recollapse of Cemented Vertebrae

INTRODUCTION

Percutaneous kyphoplasty can offer pain relief and restoration of vertebral height immediately after the procedure; however, little is known about how many vertebrae recollapse during follow-up or why recollapse occurs. In the present study, we define recollapse of a treated vertebra, assess how common it is following percutaneous kyphoplasty, and investigate risk factors for the condition.

METHODS

In total, 203 consecutive patients who underwent percutaneous kyphoplasty were reviewed after an average 12.7 months to assess what proportion of cement-augmented vertebrae had recollapsed. Potential risk factors for recollapse included age, gender, body weight, body height, body mass index, treated level, duration of symptoms, follow-up duration, preoperative T-scores, surgical approach, the intravertebral cleft, contact of polymethyl methacrylate (PMMA) with endplates, cement volume, cement leakage, and midline vertebral body height. Stepwise multivariate linear regression was conducted to predict recollapse as quantified by midline vertebral height loss.

RESULTS

Overall, 38.9% of the augmented vertebrae recollapsed. In the recollapse group, the average midline vertebral height ratio and kyphotic angles statistically significantly changed during follow-up (P < 0.05). Pain scores decreased immediately after percutaneous kyphoplasty and generally remained low at follow-up. Significant predictors of midline vertebral height loss at follow-up included presence of an intravertebral cleft, postoperative vertebral height, and non-PMMA-endplate-contact. Together, these factors accounted for 28% of the variability in midline height loss.

CONCLUSIONS

Benefits of percutaneous kyphoplasty are partly offset by subsequent recollapse. Recollapse is greater if there is an intravertebral cleft, non-PMMA-endplate-contact and an increase in the post vertebral height.

Does an osteoporotic vertebral fracture treated by balloon kyphoplasty successfully achieve bone union during the follow-up? A retrospective study with a minimum 2-year follow-up

OBJECTIVE

To investigate whether bone union is achieved in osteoporotic vertebral fracture (OVF) patients who undergo balloon kyphoplasty (BKP).

METHODS

Thirty-six vertebrae, which were followed-up for more than two years after BKP, were evaluated in the present study. Bone union was assessed by using CT scans and lateral X-ray films obtained in the sitting and supine positions.

RESULTS

Twenty-seven vertebrae exhibited bone union at the final follow-up. The VAS scores improved in all cases.

CONCLUSIONS

Unstable vertebrae after treatment may develop complications; thus special attention should be paid to the treated vertebrae until bone union has been achieved.

Unilateral versus bilateral percutaneous kyphoplasty for osteoporotic vertebral compression fractures: A meta-analysis

BACKGROUND

The debate on the efficacy of unilateral percutaneous kyphoplasty (UPKP) and bilateral percutaneous kyphoplasty (BPKP) for the treatment of osteoporotic vertebral compression fractures (OVCFs) is ongoing.This meta-analysis aimed to evaluate the clinical results of UPKP and BPKP in the treatment of OVCFs.

METHODS

Web of Science, PubMed, Embase, and the Chinese Biomedical Database publication databases were searched using a date range of January 2008 to November 2016, for studies comparing UPKP and BPKP for the treatment of OVCFs. The clinical effectiveness was assessed by comparing perioperative outcomes (surgery time, the volume of injected cement, X-ray exposure time, and kyphotic angle reduction), clinical outcomes (visual analogue scale [VAS] for pain relief and Oswestry Disability Index [ODI] for quality of life), and surgery-related complications (cement leakage and adjacent vertebral fractures). Data were analyzed using Stata/SE11.0 software.

RESULTS

Fourteen trials with 1194 patients were retrieved. The pooled results showed significant differences in surgery time (weighted mean difference [WMD] -21.44, 95% confidence interval [CI] [-23.57 to -19.30]; P < .001); volume of injected cement [WMD -1.90, 95% CI [-2.26 to -1.54); P < .001); and X-ray exposure time (WMD -13.66, 95%CI [-19.59 to -7.72]; P < .001) between UPKP and BPKP treatments. However, the pooled results showed no significant differences in kyphotic angle reduction, VAS in the short-term, VAS in the long-term, ODI, cement leakage, or adjacent vertebral fractures between the 2 surgical procedures. Following a subgroup analysis, the results based on randomized controlled trials (RCTs) indicated that there were significant differences in surgery time (WMD -24.65, 95%CI [-26.53 to -22.77]; P < .001) and the volume of injected cement (WMD -1.66, 95%CI [-1.97 to -1.36]; P < .001) between UPKP and BPKP treatment procedures, respectively. The results based on RCTs indicated that there were no significant differences, either in kyphotic angle reduction or in X-ray exposure time, between the 2 surgical procedures.

CONCLUSIONS

Compared to BPKP procedures, UPKP procedures may achieve similar clinical results in the treatment of OVCFs when assessed in terms of the pain relief, improvements in life quality, and surgery-related complications. However, UPKP procedures had a shorter operation time and volume of injected cement compared with BPKP procedures. Additional high quality and multicenter RCTs are needed to provide further robust evidence.

Better Height Restoration, Greater Kyphosis Correction, and Fewer Refractures of Cemented Vertebrae by Using an Intravertebral Reduction Device: a 1-Year Follow-up Study

PURPOSE

This study compared the radiologic and clinical outcomes of kyphoplasty with intravertebral reduction device (IRD) and vertebroplasty (VP) in treating osteoporotic vertebral compression fractures (OVCFs).

MATERIALS AND METHODS

We enrolled 75 patients with OVCFs who were aged >60 years and treated them through VP or kyphoplasty with IRD. The radiologic outcomes, namely the anterior and middle body heights (ABH and MBH, respectively) and kyphotic angle (KA), were measured preoperatively and at postoperative 1 week, 3 months, 6 months, and 1 year. The refracture was identified on the basis of a decrease in ABH, MBH, or KA compared with those at postoperative 1 week. Visual analog scale (VAS) for pain and complications were recorded. The incidence of adjacent and nonadjacent fractures was also recorded.

RESULTS

We treated 36 patients with kyphoplasty with IRD (IRD group) and 39 through VP (VP group). The patient characteristics were comparable in both groups. The KA and its restoration were more favorable after IRD than after VP. Although ABHs were not different in either group, their restoration was more efficient after IRD than after VP. MBHs, their restoration, and their refracture rates were better after IRD than after VP. VAS pain scores and complication rates were not different between the groups. The incidences of adjacent or nonadjacent fractures were not different between the 2 groups.

CONCLUSION

Our findings reveal significantly more efficient height restoration and kyphosis correction and fewer refractures in the IRD group. IRD may not increase the risk of adjacent or nonadjacent fractures.