Kyphoplasty versus Vertebroplasty

Worldwide, more than 100 million people are at risk for developing new osteoporotic spinal fractures. 20% of people over the age of 70 and 16% of postmenopausal women may get osteoporotic vertebral fractures.

Pain and a kyphotic malformation of the spine are the major symptoms. Kyphosis has a detrimental effect on bowel transit, quality of life, self-sufficiency, and mood, which ultimately shortens life expectancy significantly.

According to recent data, femoral neck fractures and spinal deformities brought on by osteoporotic vertebral fractures are both linked to increases in 5-year mortality of 23% to 34%. Numerous surgical techniques for treating osteoporotic vertebral fractures have been developed as a result of the inconsistent effectiveness of non-operative management.

At least six weeks following the fracture, vertebroplasty, which involves injecting cement into the fractured spine, is used to treat persistent discomfort. In order to reduce the possibility of leaking during cement injection and still allow for the treatment of the kyphotic deformity, balloon tamps for kyphoplasty were created.

The literature compared the short-term clinical and radiological outcomes following vertebroplasty and kyphoplasty used to treat osteoporotic fractures of the thoracic and lumbar spine using the multicenter data from the French Society for Spine Surgery (Société Française de Chirurgie de Rachis, SFCR) presented at the 2011 meeting on vertebral augmentation.

Materials and methods

Between December 2007 and December 2010, 127 patients who underwent therapy at 138 vertebral levels were included in the literature. A1, A2, or A3 Magerl fractures without pieces in the spinal canal or neurological problems qualified patients for treatment. The diagnosis of osteoporotic fracture was based on the low-energy trauma, which might have been a fall from a chair or from standing height.

Age wasn’t used as a selection factor. Magerl B and C fractures with disc and ligament instability, fractures needing internal fixation, fractures associated with tumors, neurological abnormalities, skin infection along the trocar track, and vertebra plana were among the exclusion criteria.

On the basis of whether they received kyphoplasty or vertebroplasty, the patients were divided into two groups. There were 42 patients in the kyphoplasty group and 95 levels were treated on 85 patients who underwent vertebroplasty.

Four surgeons in one location (Grenoble) conducted vertebroplasties, while 11 surgeons in five locations did kyphoplasties (Strasbourg, Lille, Poitiers, Grenoble, and Marseille). The mean patient age was 71 years in the vertebroplasty group compared to 59 years in the kyphoplasty group, which was a significant difference (P = 0.00001).

In the group receiving vertebroplasty, there were more women (P = 0.0131), and in the group receiving kyphoplasty, there were more Magerl A3 fractures (P = 0.04). In terms of topographic fracture distribution and turnaround time for surgical treatment, the groups were comparable. The median time to surgical intervention was 15 days (interquartile range: 0-120) for vertebroplasty and 10 days (interquartile range: 0-42) for kyphoplasty.

Surgical techniques

In order to reduce the fracture that caused the kyphotic deformity, vertebroplasty was performed while the patient was under general anaesthesia while lying on his or her back and supported by rolled sheets under the thorax and hips. The thoracic spine’s pedicles were used to place the trocars, while the lumbar spine’s transverse processes and ribs were used for the thoracic spine.

The T’VT trocars, manufactured by Thiebaud in Thonon, France, had a 4 mm outer diameter. Cement (Biomet V, Biomet, Valence, France) was injected under lateral and anteroposterior fluoroscopic guidance after the trocar was inserted into the anterior vertebral body. When the filling was deemed adequate or cement began to leak outside the vertebral body, the injection was stopped.

Additionally, kyphoplasty was carried out under a general anaesthetic. The patient was lying on his back. It wasn’t mentioned where the supports should be placed. The thoracic spine’s pedicles were used to place the trocars, while the lumbar spine’s transverse processes and ribs were used for the thoracic spine.

Both an introducer system and the Kyphon gadget (Medtronic, Boulogne-Billancourt, France) were employed. Two balloons were inserted into the vertebral body and filled with saline containing injectable contrast material under fluoroscopic supervision.

By using lateral fluoroscopy, balloon filling and fracture reduction were monitored. To stabilise the reduction, cement was poured into the space left after the balloon was removed. It was either KYPHX HV-R (Medtronic) or another high-viscosity radio-opaque cement that was used.

Both methods required a human viscosity check before injecting the cement, which took place an average of 4 minutes after mixing began. It was noted how much was injected. Following the procedure, early sitting was permitted as painlessly as possible, and ambulation began on day 1. There were no braces worn.

Follow-up

Baseline information for the trial included pain intensity on a 0–10 visual analogue scale (VAS), management time, and sagittal plane deformity on a lateral radiograph with the fracture in the centre. The angle between the lines drawn along the upper and lower endplates of the fractured vertebra was known as the baseline wedge angle (bWA).

The angle between the lines running along the upper endplate of the superjacent vertebra and the lower endplate of the infra adjacent vertebra was known as the baseline kyphosis angle (bKA). Positive angles denoted kyphosis, while negative angles denoted lordosis.

The following perioperative data were noted: the amount of cement injected in millilitres, the length of the operation in minutes, and the length of the hospital stay in days. Before the patient was discharged, a neurological assessment was conducted and the VAS pain score was calculated.

Anteroposterior and lateral radiographs were taken to assess the level of cement filling and to measure the postoperative wedge angle (poWA) and postoperative kyphosis angle (poKA). Since the volume injected is insufficient to assess the technical proficiency of the procedure, we noted the locations of cement leakage. Computed tomography (CT) was used to pinpoint the precise location of the leak after it was discovered.

Three months after the procedure, patients were examined for a physical examination, calculation of the VAS pain score, and anteroposterior and lateral radiographs with the fracture in the centre for measuring the 3-month wedge angle (m3WA) and 3-month kyphosis angle (m3KA). The difference between the baseline and postoperative wedge angles (bWA-poWA) was used to calculate wedge reduction.

While the baseline and postoperative kyphosis angles were used to calculate kyphosis reduction (bKA–poKA). The difference between the postoperative and 3-month wedge angles (poWA-m3WA) was used to calculate loss of wedge reduction after 3 months, and the difference between the postoperative and 3-month kyphosis angles was used to calculate loss of kyphosis reduction.

Statistical analysis

The Student’s test and the Chi2 test were used to compare quantitative and qualitative data, respectively. P values under 0.05 were regarded as significant. To evaluate the impact of several quantitative variables on WA and KA reduction and loss of reduction, Pearson’s correlation coefficients were computed.

Results

The proportion of patients lost to follow-up was 29% after vertebroplasty and 5% after kyphoplasty (P = 0.0014), and the mean follow-up was shorter in the vertebroplasty group than in the kyphoplasty group (4 months vs. 6 months, P = 0.00003). On an intent-to-treat basis, patients who were lost to follow-up were included in the analysis.

the primary follow-up data is reported. There were no discernible differences in the amount of pain experienced immediately following surgery and three months later (3-point VAS score improvement), the percentage of patients with satisfactory filling (78%), the cement leakage rate (61% in the vertebroplasty group and 51% in the kyphoplasty group), or the length of hospital stays.

Significant differences were found for the volume injected, which was 5 mL for vertebroplasty and 7 mL for kyphoplasty, as well as the operative time, which was twice as long in the kyphoplasty group as in the vertebroplasty group.

Explain the defects and the effects they have. The postoperative measurements revealed significant WA improvements in the groups undergoing kyphoplasty (mean, 6°; range, 16° to 2°) and vertebroplasty (mean, 2°; range, 0° to 35°; P = 5 109). After kyphoplasty, the WA considerably improved more than after vertebroplasty (P = 0.002).

In both groups, patients with A3 fractures experienced greater WA improvement than patients with A1 fractures (P = 0.03). No Magerl group responded to either approach more favourably than the others. After three months, neither group experienced a significant loss in WA.

The postoperative KA improvement was not significant in either group (P = 0.12 for vertebroplasty and P = 0.35 for kyphoplasty). Postoperative KA reduction was not significant with either method (P = 0.16). The loss of KA reduction after 3 months was not significant (P = 0.21 for vertebroplasty and P = 0.37 for kyphoplasty). However, loss of KA reduction was greater for A2 fractures than for A1 fractures (P = 0.05), whereas no significant difference was seen between A1 and A3 fractures (P = 0.41).

provide information about vertebral filling. After vertebroplasty than after kyphoplasty, Z3 filling—defined as uniform cement dispersion throughout the vertebral body—was more prevalent (P = 0.03). demonstrates where and when leaks occur. Although the difference was not statistically significant (P = 0.07), leaks in the anterior direction (type 3) were more frequent after vertebroplasty.

The postoperative WA improvement in the vertebroplasty group showed a weak negative association with the time to surgery (correlation coefficient, 0.23) and a weak positive correlation with age in the correlation analysis (correlation coefficient, 0.39).

There were no documented deaths that could be attributed to the procedures. The cement did not cause any systemic issues. There were no additional vertebral fractures in the treated or nearby vertebrae, and there were no neurological sequelae. One patient in the vertebroplasty group needed two more surgeries to cure an early infection.

Discussion

The retrospective multicenter design is subject to numerous biases in the literature. Additionally, whereas almost all of the patients undergoing vertebroplasty came from a single center, the kyphoplasty patients were recruited from a number of different centers. Despite using low-energy trauma as an inclusion criterion, the vertebroplasty group’s mean age was higher than the kyphoplasty group’s.

Each center’s practice routines appear to be extremely important. In this case series, early vertebroplasty or kyphoplasty was not considered for individuals beyond the age of 80. Age and WA improvement, however, did not correlate in any group. Given the lack of published recommendations, the decision between cement injection and first bracing was left up to the individual judgement of each centre.

As a result, only patients with chronic discomfort despite bracing were treated with cement injection in some centres. The age discrepancy and varied criteria for kyphoplasty in certain centres may be explained by the fact that each centre employed its own definition of low-energy trauma.

Another limitation of our study is the inherent lack of accuracy in hand measurements of angles and heights. Additionally, the upper endplate’s double concavity may make it difficult to position it correctly. Regular computed tomography pictures would provide more precise results for the examination of impaction and reduction at the centre of the endplate, which is the only way to significantly improve mechanical support for the intervertebral disc.

Finally, the VAS pain score was the only clinical evaluation factor used for the study’s participants. In the oldest patients, calculating a functional score can be challenging. Therefore, we concentrated on providing pain relief and short-term structural improvements.

Outcomes

Similar results were obtained following vertebroplasty and kyphoplasty in terms of discomfort, cement leaks, complications, and deformity reduction. Our statistics on pain are in agreement with previous studies. At the most recent follow-up, we did not assess function. Right now, it’s widely accepted that treating vertebral fractures with early vertebroplasty or kyphoplasty improves survival and quality of life and enables a quicker return to work.

Kyphoplasty has been shown to have a 7% higher survival rate than vertebroplasty.It has not been established that the greater decrease achieved with kyphoplasty has any immediate advantages. In our investigation, the two groups had similar leak rates and topographic distributions of leaks (with a predominance of lateral and cranial leaks).

Our patients weren’t negatively affected clinically by leaks. According to certain reports, kyphoplasty reduces leaks. The high leak rate in our study can be attributed to the kyphoplasty group receiving a large volume (7 mL on average) of cement injection at a low viscosity stage. The current trend is to inject at a stage of higher viscosity, following more time spent mixing.

Since the initial research, technical advancements achieved by surgeons have helped to reduce the leak rates in addition to changes in the cements that are currently accessible. Although the difference was not statistically significant, vertebroplasty was associated with a higher incidence of anterior leakage in our sample.

Between our two groups, complications were not significantly different. The rates of pulmonary embolism and neurological complications following vertebroplasty, however, were higher according to Taylor et al. Our study’s follow-up was brief, but we didn’t record any new fractures. Neither group’s decreased quality was impacted by the treatment amount.

In contrast, Phillips et al. found that the mean KA improved by 8.8°, with thoracic levels experiencing greater increases than lumbar levels. Finally, the WA greatly improved with both methods. There were no clinical differences between the mean KA after vertebroplasty and after kyphoplasty at 3 months, indicating that restoring a WA higher than 10° would be advantageous.

To date, no target WA value has been revealed, though. Our study found some KA improvements, but they were not statistically significant (1° on average in both groups). There was little connection between KA and WA advances (correlation coefficient, 0.39). The kyphotic deformity is not lessened by treating the wedge deformity, therefore. It appears that the neighbouring discs have “consumed” the WA enhancement.

Teng et al. observed a KA improvement of 4.5° to 5°, while Shin et al. reported a 7° improvement in the KA right away following the surgery. Magerl A3 fractures regularly have greater reduction quality.

Therefore, when interpreting the results, it is important to consider the bias introduced by the higher prevalence of these fractures in the kyphoplasty group. We did not find any proof that one technique was better than the other for Magerl A1 fractures, which are more challenging to reduce.

Technique

Between vertebroplasty and kyphoplasty, there are a number of technical distinctions highlighted in the literature. With vertebroplasty, the basic technique for reducing the deformity involves positioning the patient while they are under general anaesthesia to enhance spinal lordosis.

Better reduction was reported by Carlier et al. in cases with intravertebral clefts. Tropiano et al. used a Cotrel frame and casting to achieve good results with closed reduction. In our study, hyperlordosis made sure that the WA improved by 2° right away after surgery. By putting cement in the spaces left in the cancellous bone after reduction, vertebroplasty stabilises the fracture.

To guarantee raising of the upper endplate during cement injection, reinforced trocars have been created; however, there are no comparison studies demonstrating the effectiveness of this technique. It was recommended to employ balloon tamps to elevate the upper endplate and thereby better decrease the deformity.

Although there is no proof that these results translate into therapeutic advantages, our data support the notion that kyphoplasty promotes larger WA improvements. There are now being developed further techniques for reducing through intracorporeal treatments. Before injecting cement into the vertebral body, the Spinejack (Vexim SA, Balma, France) is inserted into the vertebral body via a pedicle.

Additionally, a system for vertebral body stenting has been developed (VBS, Synthes, Issy-les-Moulineaux France). Clinical and economic studies should be conducted to evaluate these promising techniques.

In our case-series, the variations in operative methods account for the variations in operative time, filling, and the effect of treatment time. In comparison to kyphoplasty, vertebroplasty required less time during surgery. Given that patients with compression fractures are frequently weak, this topic merits investigation.

It could be possible to do the surgery while under ambulatory general anaesthesia. We couldn’t find any prior information on vertebral body cement filling. In our study, vertebroplasty was linked to Z3 filling that was uniform in both the cranio-caudal and lateral directions. In kyphoplasty, bone compression during balloon expansion likely prevents cement from dispersing properly.

We discovered a tenuous relationship between the quality of the decrease and the time to operational management. Similar to this, Philips et al. found that quick vertebroplasty following the accident resulted with higher WA improvement (7.1° within the first week vs. 1.3° after 4 weeks, P 0.05). No association with kyphoplasty was discovered. Thus, it appears that the length of time before surgery has no effect on the reduction that kyphoplasty achieves.

Conclusion

The results demonstrate the usefulness of kyphoplasty in relieving pain and deformity associated with osteoporotic vertebral fractures despite the case-series’ notable variability. Early vertebroplasty, which is quicker and less expensive than kyphoplasty, is still beneficial.

The rate of clinically discernible complications is identical, and cement diffusion into the cancellous bone is superior to that of kyphoplasty. Finally, even in patients with osteoporosis, Magerl A1 fractures are more difficult to treat with either technique.

Disclosure of interest

L. Garnier: There is no financial connection to industry. J. Tonetti: SPINEART is a consultant. A. Bodin: No financial connection to the industry; unpaid research project with THIEBAUD MÉDICAL H. Vuaillat: Medtronic is a consulting firm. R. Assaker: Medtronic is the consulting firm. C. Court: Medtronic, a consulting firm. P. Merloz: This article has no conflicts of interest.

Acknowledgements

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