Osteoporotic vertebral compression fractures (OVCFs) are a common and serious consequence of osteoporosis and have become more prevalent as life expectancy increases. These fractures occur when weakened vertebrae collapse, frequently causing severe pain, restricted mobility, various morbidities, and even death [1,2].

Vertebral augmentation is a minimally invasive procedure to relieve pain and manage complications from OVCFs by injecting bone cement into the fractured vertebra to stabilize and restore height. There are two main types: vertebroplasty, in which bone cement is injected directly into the collapsed vertebra, and kyphoplasty, in which a balloon is first inserted into the fractured vertebra to create a cavity that is then filled with bone cement, which helps restore the original vertebral shape and reduce kyphosis [3]. Although these procedures offer benefits such as pain relief, vertebral height restoration, and boosted patient function, cement leakage, adjacent vertebral fracture, increased pain, and mortality are some complications that occur [4,5].

Sarcopenia is characterized by the progressive loss of skeletal muscle mass, quality, and strength associated with aging [6]. Recent studies indicate the negative impacts of sarcopenia on elderly patients undergoing orthopedic and trauma care, which contributes to increased risks of falls and fractures, resulting in decreased independence and decreased quality of life (QoL) [7,8]. Several studies have examined the effects of sarcopenia on patients undergoing vertebral augmentation for OVCFs, but their results are inconsistent. Some studies reported that sarcopenia did not affect outcomes after the procedures [9–12], while others showed significantly poorer results in patients with sarcopenia [13–16]. Thus, we conducted this meta-analysis to thoroughly review all available publications on this topic and provide evidence on the impact of sarcopenia on these procedures. We hypothesized that the presence of sarcopenia negatively affects outcomes after kyphoplasty or vertebroplasty, specifically vertebral refracture, residual back pain (RBP), clinical performance, hospital stay, and mortality.

A total of 103 records were identified. After removing duplicates, 43 records were screened for titles and abstracts. After excluding ineligible studies, we assessed the full texts of 23 records. Nine articles were excluded for several reasons. Finally, 14 studies were included in the meta-analysis. Fig. 1 summarizes the screening and selection processes for the study.

The characteristics of the included studies are presented in Table 1. The studies consisted of 2,197 patients with a pooled mean age of 73.06 years, and there were more females (n=1,600, 72.83%) than males (n=597, 27.17%). A total of 813 patients were diagnosed with sarcopenia and 1,384 without sarcopenia. The more common procedure was kyphoplasty, reported in 11 studies [9,11–16,20–23], followed by vertebroplasty, reported in five studies [10,20,21,24,25]. The follow-up time varied from 1 to 79 months.

Supplement 1 illustrates the methodological quality of all included studies. The Newcastle-Ottawa Scale was used to assess these studies because they were all observational in nature. Eight studies were rated as high-quality, with four scoring 7 points, four scoring 8 points, and three scoring 9 points. Three studies were deemed to have a high risk of bias, each scoring 6 points.

Table 2 shows the results of the meta-analysis of bone and muscle measurements in patients with OVCF. Patients with sarcopenia had significantly poorer bone and muscle health than those without sarcopenia, as demonstrated by a lower bone mineral density (MD, −0.42; 95% CI, −0.67 to −0.17; p<0.001), weaker handgrip strength (MD, −5.66; 95% CI, −9.42 to −1.89; p=0.003), and notably decreased in muscle mass.

Our meta-analysis reviewed 14 studies that included 2,197 patients who underwent vertebral augmentation for OVCFs. The findings revealed that patients with sarcopenia had elevated risks of vertebral refracture, RBP, poorer postoperative clinical performance, longer hospital stays, and mortality following the procedures compared to those without sarcopenia. The refracture risk increased with age in patients with sarcopenia undergoing vertebral augmentation. Additionally, the impact of sarcopenia on vertebral refracture was more pronounced following kyphoplasty than following vertebroplasty.

Sarcopenia is a progressive age-related condition characterized by decreased skeletal muscle mass, strength, and function [6]. After the age of 65 years, individuals typically lose 1.4% of muscle mass and 1.4%–2.5% of muscle strength annually [26]. Therefore, the prevalence of sarcopenia rises with age, impacting a significant portion of the elderly population. This, combined with increasing life expectancy, has made sarcopenia a significant public health concern. The consequences of sarcopenia extend beyond physical frailty, as affected individuals face higher risks of falls, fractures, chronic diseases, and disability, leading to a diminished QoL and greater dependence on others [27]. The economic burden associated with caring for sarcopenic individuals is also considerable [28].

Vertebral refracture is one of the most common complications after vertebral augmentation, with incidence rates reported as high as 52%. It is associated with various factors, including advanced age, low body mass index, bone loss, fracture in the thoracolumbar junction, and so forth [29–33]. Many studies have highlighted the critical role of bone health in preventing refracture. Previous studies have reported a significant connection between bone and muscle health, showing considerable bone loss following muscle deterioration [34–36]. These findings support our observations in this meta-analysis among patients with OVCF, where those with sarcopenia exhibited significantly worse bone and muscle conditions than those without sarcopenia. Additionally, losing muscle mass and strength increases fall risk and weakens the paraspinal and core muscles, reducing spinal stability and adding stress to the vertebrae, possibly leading to fractures [21,27,37,38]. Our study has confirmed that patients with sarcopenia have a substantially higher risk of postoperative refracture than those without sarcopenia, with increasing risk with age, which is also consistent with previous research linking these factors to an elevated risk of spine fractures [39–41]. A key finding in our meta-analysis was that poor muscle health was more strongly linked to increased refracture risk in patients who undergo kyphoplasty than in those who undergo vertebroplasty, indicating that it may be a risk factor for poorer outcomes after kyphoplasty. Restoring vertebral height in the context of poor muscle quality, combined with changes in vertebral stiffness caused by cement augmentation, can compromise spinal stability and increase stress on adjacent vertebrae, ultimately leading to a significantly higher risk of refracture [42–44]. However, this result should be interpreted cautiously, as fewer studies and participants were involved in vertebroplasty than in kyphoplasty (two studies with 248 participants versus eight studies with 1,334 participants). This underscores the need for additional research to explore the impact of sarcopenia on outcomes after vertebroplasty.

RBP is recognized as a significant global issue, severely impacting QoL, leading to disability, and reducing physical performance [45]. Previous studies have identified factors contributing to RBP after kyphoplasty or vertebroplasty, such as low bone density, bone cement volume, or dorsal fascia injury [46–48]. Recently, attention has turned to the role of sarcopenia in RBP following spine surgery. Our study found that patients with sarcopenia experienced RBP after vertebral augmentation compared to those without sarcopenia. Muscles are crucial for stabilizing the spine and facilitating its functional movement. When these muscles weaken, the spine loses essential support, leading to misalignment and increased stress on the vertebral disks and joints, exacerbating pain. This can create a vicious cycle where pain reduces physical activity, further contributing to muscle atrophy and increased pain sensitivity [37,48]. Moreover, muscle loss worsens bone quality, which was associated with RBP because of the changes in alignment and stability of the spine [46,49,50].

In this study, patients with sarcopenia experienced longer hospital stays than those without sarcopenia. They also exhibited significantly poorer clinical outcomes at 1 month and 1 year after surgery, reporting higher pain levels and more severe functional impairments following vertebral augmentation. Increased pain and reduced functional recovery indicate that sarcopenia may intensify the physical strain and healing difficulties associated with spinal procedures and postoperative rehabilitation, resulting in prolonged recovery times. These findings are consistent with previous studies, which have repeatedly highlighted the adverse impact of sarcopenia on lumbar spinal diseases and surgical outcomes [12,51–54].

Patients with sarcopenia were shown to have a higher risk of mortality at 1-year and longer-term follow-up after vertebral augmentation. The presence of sarcopenia was also reported to increase the risk of mortality after spinal surgery [55–57]. Sarcopenia adversely affects patients due to associated morbidities, frailty, chronic systemic inflammation, and hormonal changes, leading to hospital readmissions, poorer health conditions, and mortality [58–60]. Moreover, sarcopenia, which causes gait and balance impairments, significantly increases the risks of falls and severe injuries [61].

This study has several limitations. First, most studies were retrospective, which may have introduced bias. Second, all the included studies were observational, making them susceptible to various biases that could affect the reliability of the findings. Third, there was significant heterogeneity among the studies included in our analysis. For instance, most of the studies that investigated the influence of sarcopenia on refracture were from China, showing a higher refracture risk in patients with sarcopenia, while studies outside China found no difference. The overrepresentation of the Chinese population highlights the need for further research on other populations to help generalize these findings. Additionally, studies with a longer mean follow-up (over 1 year) showed a more significant impact of sarcopenia on vertebral refracture, unlike those with shorter follow-ups. Finally, the use of various tools for muscle assessment created diagnostic inconsistencies [7,62,63]. Among the studies reviewed, six combined two or three factors-muscle mass measurement and muscle strength or physical performance [9,11–15] while the rest relied solely on muscle mass measurement to diagnose sarcopenia [10,16,20–25]. These differing methodologies contributed to the considerable heterogeneity in the meta-analysis, underscoring the necessity for a standardized and effective tool for detecting sarcopenia across the general population.

It is crucial to recognize that sarcopenia significantly affects outcomes after vertebral augmentation. Early diagnosis and timely intervention are essential to improve muscle mass and quality, thereby minimizing adverse outcomes, preventing patient dependency, and enhancing QoL. Regular physical activity, particularly resistance training, and a protein-rich diet are vital for building and maintaining muscle mass after the procedure [64–66].

Sarcopenia adversely affects patients undergoing vertebral augmentation for OVCFs, increasing the likelihood of vertebral refracture, particularly with advancing age. These patients are also more prone to RBP, poor clinical outcomes, prolonged hospital stay, and higher mortality risk. Early diagnosis of sarcopenia in high-risk patients and the implementation of comprehensive management strategies to enhance and sustain muscle health are advised to prevent adverse outcomes.