Sacroplasty is a minimally invasive procedure in which bone cement is injected into a fractured sacrum to stabilize the break and relieve pain. It works on the same principle as vertebroplasty, its better-known cousin used for spinal compression fractures, but targets the large triangular bone at the base of the spine. The procedure is typically offered to people whose sacral fractures have not improved with rest, medication, and other conservative measures, and it has shown strong results for both pain relief and restored mobility in clinical studies.
Why the Sacrum Matters and How It Breaks
The sacrum sits at the bottom of the spine, wedged between the two hip bones. It functions as the keystone of the pelvis, transferring and distributing the weight of your entire upper body into your hips and legs. Even small changes to the sacrum’s structure from trauma or bone loss can produce significant symptoms, because any disruption to this load-bearing hub throws off the balance of the entire pelvic ring.1Injury. Sacral fractures: An updated and comprehensive review
Sacral insufficiency fractures, the type most commonly treated with sacroplasty, develop when normal everyday forces act on bone that has already been weakened. Osteoporosis is the leading culprit, and these fractures typically appear in elderly patients with no clear history of a fall or injury.2PubMed Central. Sacral insufficiency fracture, usually overlooked cause of lumbosacral pain The fractures tend to cluster in the sacral alae, the wing-shaped areas on either side of the sacrum. That location is not random: the alae have the highest ratio of spongy inner bone to hard outer bone anywhere in the sacrum, making them structurally vulnerable. The central part of the sacrum, by contrast, is reinforced by additional layers of cortical bone and the posterior neural arch, and the extreme outer edges are braced by thick ligaments connecting the sacrum to the hip bones.3PubMed Central. Anatomical and Biomechanical Analyses of the Unique and Consistent Locations of Sacral Insufficiency Fractures
Radiation therapy is another well-documented cause. Patients treated with pelvic radiation for cancers of the prostate, rectum, cervix, or other pelvic organs can develop weakened bone in the sacrum months or years later. Radiation damages the cells responsible for building new bone and injures the blood vessels that supply the bone, leaving it brittle and prone to fractures under ordinary stress.4PubMed Central. Insufficiency fracture after radiation therapy The sacral alae are again the most common fracture site in post-radiation patients.5PubMed Central. A Comprehensive Narrative Review of the Impact of Pelvic Radiotherapy on Pelvic Bone Health
Why These Fractures Are So Often Missed
One of the frustrating realities of sacral insufficiency fractures is that they frequently go undiagnosed for weeks or months. The symptoms, typically deep low-back or buttock pain that worsens with standing and walking, overlap with many other conditions. Patients and clinicians alike often attribute the pain to degenerative disc disease, sciatica, or muscle strain.
Standard X-rays are particularly bad at catching these fractures. One study found that plain radiographs detected sacral insufficiency fractures only about 29% of the time. CT scans performed much better, picking up roughly 94% of fractures, but MRI caught every single one and revealed more complex fracture patterns than CT in about two-thirds of cases.6PubMed Central. Superiority of MRI for Evaluation of Sacral Insufficiency Fracture MRI’s advantage comes from its ability to show bone marrow swelling and surrounding soft-tissue changes that signal an active fracture, not just the crack in the bone itself. If you have unexplained pelvic or low-back pain and risk factors like osteoporosis or a history of pelvic radiation, an MRI is the gold-standard imaging test.
Who Is a Candidate for Sacroplasty
Sacroplasty is not a first-line treatment. The standard starting approach for sacral insufficiency fractures is conservative care: pain medication, limited bed rest, physical therapy, and treatment of underlying bone loss. Most clinical guidelines recommend trying these measures for several weeks before considering intervention. Sacroplasty enters the picture when conservative management fails. Candidates are patients with persistent pain, those who cannot tolerate the prolonged immobilization that healing requires, or patients whose bone mineral density is too low for the fracture to heal reliably on its own.7PubMed Central. Sacroplasty for Sacral Insufficiency Fractures: Narrative Literature Review on Patient Selection, Technical Approaches, and Outcomes
In practical terms, the typical candidate looks something like this:
- Elderly patients with osteoporosis whose fractures cause disabling pain that does not respond to weeks of medication and rest.
- Cancer patients with sacral metastases who have tumors that have spread to the sacrum and are causing intractable pain.
- Post-radiation patients who developed insufficiency fractures after pelvic radiotherapy and have limited bone-healing capacity.
- Patients at high risk from immobility who face serious complications from extended bed rest, such as blood clots, pressure sores, pneumonia, or rapid muscle wasting.
Before the procedure, clinicians generally want to optimize a patient’s bone health with medication. Bone-building drugs given before or alongside sacroplasty have been shown to improve outcomes.7PubMed Central. Sacroplasty for Sacral Insufficiency Fractures: Narrative Literature Review on Patient Selection, Technical Approaches, and Outcomes Patients who are not candidates for surgery (due to age, frailty, or other medical conditions) are often good candidates for sacroplasty precisely because the procedure is so much less invasive than open surgical fixation.
How the Procedure Works
Sacroplasty is performed with the patient lying face-down, typically under conscious sedation rather than general anesthesia. The physician uses imaging guidance to place one or more large-bore needles through the skin and into the fractured area of the sacrum. Once the needle tip is properly positioned inside the fracture, a specially prepared bone cement called polymethyl methacrylate (PMMA) is injected. The cement fills the fracture voids and hardens within minutes, stabilizing the bone internally.
Imaging guidance is essential for safe needle placement and cement delivery, but clinicians use different approaches. Some centers use a combination, placing the needle under CT guidance for precise positioning and then switching to real-time fluoroscopy (live X-ray) for the actual cement injection so the physician can watch the cement flow and stop immediately if it starts leaking outside the bone.8PubMed Central. Sacroplasty by CT and fluoroscopic guidance: is the procedure right for your patient? A cadaver study comparing approaches found that CT guidance produced less cement leakage but exposed the patient to more radiation, while fluoroscopy-guided procedures were faster.9PubMed Central. Sacroplasty in a cadaveric trial: comparison of CT and fluoroscopic guidance with and without balloon assistance
A simplified single-needle technique has also been described, in which the physician uses just one needle placed through a lateral approach. In a small series of ten patients, median pain scores dropped from 7 out of 10 before the procedure to 0 afterward.10PubMed Central. Single-Needle Lateral Sacroplasty Technique The procedure generally takes under an hour, and most patients go home the same day or the next morning.
What Results to Expect
The evidence consistently shows that sacroplasty provides rapid, meaningful pain relief. In one study of 49 patients, the average pain score dropped from about 7.8 before the procedure to 3.4 at one month, and roughly two-thirds of patients saw their pain cut by more than half. Mobility also improved: 36 of 49 patients experienced significant gains in functional movement, 16 recovered full activity, and none were bedridden at one month.11World Neurosurgery. Outcomes Associated with Functional Mobility and Pain Amelioration in 49 Patients After Sacroplasty: A Single-Center Study Another study tracked pain scores at multiple time points and found that the average score dropped from about 7.5 before the procedure to 4.1 at one day, 3.3 at one month, and 3.2 at three months, suggesting that the early improvement is durable.12PubMed Central. Effects of Percutaneous Sacroplasty on Pain and Mobility in Sacral Insufficiency Fracture
These outcomes appear comparable to vertebroplasty, its more established counterpart for spinal compression fractures. A study directly comparing the two procedures found that sacroplasty produced relatively long-lasting improvements in pain, mobility, and the ability to perform daily activities on par with vertebroplasty results.13PubMed Central. Sacroplasty versus vertebroplasty: comparable clinical outcomes for the treatment of fracture-related pain
How Sacroplasty Stacks Up Against Other Treatments
A systematic review pooling data from hundreds of patients compared sacroplasty, conservative management, and surgical fixation with screws and rods. Sacroplasty produced the largest pain reduction, with an average drop of about 5.8 points on the standard 10-point pain scale. That was significantly better than conservative treatment, which averaged about 3.7 points of relief, and also significantly better than surgical fixation, which averaged about 4.1 points.14PubMed Central. A Systematic Review of Sacral Insufficiency Fractures: Treatment Modalities and Outcomes
The comparison with surgical fixation is particularly worth noting. Open surgery with screws and rods involves general anesthesia, a longer recovery, and higher complication rates, yet it did not outperform sacroplasty for pain relief in the pooled data. Surgery still has a role when there is actual instability in the pelvic ring that cement alone cannot address, but for the majority of sacral insufficiency fractures, sacroplasty achieves better pain outcomes with far less physiological stress.
Sacroplasty for Cancer-Related Sacral Pain
Cancer that has spread to the sacrum is one of the more challenging pain scenarios in oncology. These metastatic deposits weaken the bone and can cause deep, relentless pain that is difficult to control with medication alone. Sacroplasty has been used successfully for these patients, providing both structural reinforcement and significant pain relief.
A pilot study treating patients with sacral metastases from lymphoma and lung cancer reported substantial and immediate pain relief that lasted beyond three months.15PubMed Central. Percutaneous sacroplasty for sacral metastatic tumors under fluoroscopic guidance only A larger study compared sacroplasty alone against sacroplasty combined with radiofrequency ablation (a technique that uses heat to destroy tumor tissue) for painful sacral metastases. Both approaches were safe and effective, but the combination achieved a higher overall pain relief rate: about 90% compared to 76% for cement alone.16PubMed Central. Percutaneous Sacroplasty with or without Radiofrequency Ablation for Treatment of Painful Sacral Metastases For cancer patients, the goals are different from osteoporotic fracture patients. The aim is palliative: reducing suffering and preserving quality of life rather than healing the fracture.
Risks and Complications
Sacroplasty is generally considered safe, but it is not risk-free. The primary concern is cement leakage, where the injected PMMA escapes the bone and enters surrounding tissues. If cement leaks into areas near nerve roots, it can cause radiculopathy, a painful condition characterized by nerve-related pain radiating into the leg. Case reports describe patients developing nerve root compression from cement that encased nearby sacral nerves, sometimes requiring surgical decompression to remove the hardened material.17Journal of Neurosurgery: Spine. Sacral radiculopathy due to cement leakage from percutaneous sacroplasty, successfully treated with surgical decompression
In practice, most cement leakage is minor and causes no symptoms. One study comparing traditional cement sacroplasty with a newer radiofrequency-based approach found an 8.1% rate of leakage in the cement group, all of which were asymptomatic, while the radiofrequency group had no leakage at all.18PubMed. Clinical Improvement and Cost-effectiveness of CT-guided Radiofrequency Sacroplasty (RFS) and Cement Sacroplasty (CSP) Other potential complications include infection at the needle site, bleeding, and temporary worsening of pain, though all of these are uncommon. The sacrum’s proximity to the sacral nerve roots and the presacral venous plexus is what makes imaging guidance so critical: the physician needs to see exactly where the needle and the cement are going in real time.
Radiofrequency Sacroplasty and Newer Approaches
Traditional sacroplasty relies on PMMA bone cement, but alternative techniques have emerged. Radiofrequency sacroplasty uses a probe that heats and stiffens a specialized filler material inside the bone, rather than injecting liquid cement that hardens on its own. The clinical results in terms of pain relief and functional improvement appear equivalent to conventional cement injection, with the added advantage of eliminating the risk of cement leakage.18PubMed. Clinical Improvement and Cost-effectiveness of CT-guided Radiofrequency Sacroplasty (RFS) and Cement Sacroplasty (CSP)
For patients with pelvic instability beyond what cement alone can fix, some surgeons have combined sacroplasty with iliosacral screw fixation. This hybrid approach uses both cement for internal reinforcement and titanium hardware to stabilize the connection between the sacrum and the hip bones.19PubMed Central. Combined Sacroplasty and Iliosacral Fixation Using Triangular Titanium Implants for the Treatment of Sacral Insufficiency Fractures with Concomitant Sacral Instability This is a more involved procedure and is reserved for more complex fracture patterns where the pelvic ring has lost structural continuity.
Living with a Sacral Fracture After Treatment
Whether you undergo sacroplasty or heal through conservative care, the fracture itself is a signal that your bone health needs long-term attention. Osteoporosis does not go away after the fracture is treated, and patients who have had one insufficiency fracture are at elevated risk for additional fractures in the spine, pelvis, and hip. Ongoing treatment with bone-protective medication, adequate calcium and vitamin D intake, fall prevention strategies, and weight-bearing exercise (once cleared by your physician) are all part of reducing that risk.
For patients who had radiation-induced fractures, monitoring pelvic bone health over time is especially important because radiation damage to bone is permanent and cumulative. Periodic imaging may be warranted to catch new fractures early, since the same forces that caused the first fracture remain at play.
Recovery after sacroplasty tends to be swift relative to the alternatives. Most patients begin walking within hours to a day of the procedure. Physical therapy focused on gentle strengthening and balance can help rebuild the muscle support around the pelvis that typically deteriorates during the weeks or months of pain-limited mobility that preceded treatment. The transition from bed-bound to active can feel dramatic for patients who have been unable to stand comfortably for weeks, but the procedure fixes the structural problem rather than the underlying bone disease, which is why continued medical management of osteoporosis or the underlying cancer remains essential after the cement has hardened.