A meta-analysis comparing unilateral vs bilateral approaches for percutaneous vertebral augmentation in osteoporotic vertebral compression fractures
A tiny crack in a single bone can profoundly impact the life of an elderly individual, often making simple acts like getting out of bed an excruciating ordeal.
Osteoporotic vertebral compression fractures (OVCFs) are a common and painful consequence of osteoporosis, affecting millions of elderly individuals worldwide each year 1 . For those who don't find relief with conservative treatments like bed rest and bracing, minimally invasive procedures known as Percutaneous Vertebral Augmentation (PVA) offer a lifeline.
These procedures involve injecting special bone cement into the fractured vertebra to stabilize it and relieve pain. However, a potential complication looms over these otherwise successful surgeries: cement leakage.
When the liquid cement escapes from the vertebral body, it can sometimes lead to serious neurological damage or pulmonary embolism 2 .
A key surgical decision is whether to approach the vertebra from one side (unilateral) or both (bilateral). But which technique is better at minimizing this risk? A recent meta-analysis dives into the evidence to provide an answer.
The traditional method where surgeons access the vertebral body through both pedicles (the bony bridges on either side of the vertebra).
A lingering question has been whether the unilateral approach can adequately fill the vertebral body and, most importantly, if it carries a different risk of cement leakage compared to the bilateral approach.
To bring clarity to this surgical debate, researchers performed a meta-analysis, a powerful statistical method that combines data from multiple independent studies. Published in Turkish Neurosurgery in 2022, this analysis aimed to directly compare the incidence of cement leakage between unilateral and bilateral PVA for OVCFs 5 .
| Outcome Measure | Unilateral PVA | Bilateral PVA | Statistical Significance | Findings |
|---|---|---|---|---|
| Cement Leakage Incidence | Similar rate | Similar rate | Not Significant (p=0.182) | The overall risk of cement leakage was not different between the two approaches 5 . |
| Cement Volume Injected | Less cement used | More cement used | Significant (p<0.001) | Unilateral procedures required, on average, 1.34 ml less cement 5 . |
While the overall leakage rates were similar, the story became more interesting when the researchers looked at the type of PVA procedure performed. They conducted a subgroup analysis separating kyphoplasty (PKP) from vertebroplasty (PVP).
In kyphoplasty (PKP), the unilateral approach was associated with a significantly lower incidence of cement leakage compared to the bilateral approach (Risk Ratio=0.65) 5 .
This suggests that for kyphoplasty, opting for a unilateral approach may indeed offer a safety advantage in preventing cement leakage.
The primary finding that unilateral PVA does not carry a higher overall risk of cement leakage is significant. It assures surgeons that choosing this technically demanding but less invasive approach does not inherently increase the danger of this particular complication 5 .
The fact that unilateral procedures used less cement but achieved similar clinical outcomes and leakage rates challenges the notion that "more cement is better." It suggests that optimal cement distribution, rather than sheer volume, is the key to a successful surgery 4 .
It is important to view the risk of cement leakage in context. While it is the most common complication, a systematic review found that the vast majority of cement leaks are asymptomatic and do not lead to neurological compromise or other serious issues 7 .
The quest to perfect vertebral augmentation continues. Surgical techniques are constantly being refined, like the novel "P TO P" unilateral extrapedicular approach, which reports excellent cement distribution and a low leakage rate of 11.46% in one study 3 . Similarly, "decompressed kyphoplasty," which uses a suction pump to guide low-viscosity cement, has shown promise in significantly reducing leakage, particularly into the disc space 2 .
Meanwhile, material science is also advancing. The development of high-viscosity cements is another frontier. Some research indicates that these cements are more predictable during injection and are associated with a lower leakage rate and better short-term pain improvement compared to low-viscosity cements 8 .
Provides real-time X-ray guidance, allowing the surgeon to see the needle's placement and cement flow on a screen 6 .
A specialized bone needle used to create a precise pathway through the pedicle and into the vertebral body 6 .
The most common type of bone cement. It hardens to create an "internal cast" that stabilizes the fracture 1 .
Inflated inside the collapsed vertebra to create a cavity for the cement, which can help restore height and allow for lower-pressure injection 6 .
A specialized syringe or gun that allows for controlled, steady injection of the cement 1 .
The debate between unilateral and bilateral approaches is not about finding a single winner, but about matching the right technique to the right patient and situation. The 2022 meta-analysis offers a clear, evidence-based message: the unilateral approach is not inferior to the bilateral approach in preventing cement leakage and requires less cement.
This evidence empowers surgeons to choose the unilateral approach—particularly for kyphoplasty—with confidence, leveraging its benefits of shorter operation time and reduced tissue trauma without fearing a higher complication rate. As surgical techniques and materials continue to evolve, the future for patients suffering from these painful fractures looks brighter and more stable.