Interventional News: Unilateral Decision — Adopting a Unilateral Approach to Vertebral Compression Fractures
By David Shelley, MD
Radiology Today
Vol. 21 No. 5 P. 26

Osteoporosis can be the cause of vertebral compression fractures and femur fractures in 24.5% of women and 5.1% of men aged 65 and older.1 The average 10-year probability of patients aged 50 and older having a major osteoporotic fracture is 7.4%.2 That number may be higher because patients do not always seek treatment. In a study of 2,887 adult subjects aged 38 to 87, the overall prevalence of vertebral fractures was 11.8% in women and 13.8% in men, and there were multiple fractures in 30% of cases.3

In patients with osteoporosis, a fall or even a sneeze or cough can cause a compression fracture of the vertebral body, particularly if the osteoporosis is untreated. Interventional radiologists or other specialty-trained physicians can treat painful and quality of life–limiting fractures with balloon kyphoplasty or vertebroplasty. Without appropriate balloon kyphoplasty or vertebroplasty, compression fractures can cause an increase in bone and muscle strength loss, increased use of narcotics, and a marked decrease in quality of life measures. In recent years, evolving procedures such as the unilateral approach to balloon kyphoplasty have demonstrated significant advantages.

Advances in Unilateral Surgery
With the option to perform vertebroplasty—cement injected to stabilize fractures—or balloon kyphoplasty—a balloon system used to create a void and reduce the fracture before cement is injected—I opt for the latter. Both offer significant pain relief, but, in my opinion, the balloon is a safer method for vertebral augmentation. Certainly, after the void is created and compacts the trabecular bone, there is less chance of cement extravasation—leakage into surrounding tissues—compared with vertebroplasty.

A bilateral bipedicular approach to balloon kyphoplasty has worked very well for years. Using two straight introducer needles, a surgeon accesses the vertebrae from a bilateral transpedicular or extrapedicular approach. After placing bilateral balloon catheters into the respective sides of the vertebral body, both balloons are inflated in hopes of reducing the fracture and creating voids to begin placement of cement into the vertebral body and the fracture. It can be difficult to access the opposite side with a straight introducer needle, which is why two are often required. There is also the option of taking a unipedicular approach with a balloon catheter designed with a preset curve. However, the curved device must be inserted through the straight trocar, and manipulating the fixed curve around the vertebrae can be challenging.

Recently, I have begun to perform unilateral balloon kyphoplasty using a newer catheter technology, the only one available that is rated at 700 psi and is steerable, rather than fixed in a straight or curved form. As a result, I can move the catheter to either side of the vertebrae through a single incision. The catheter has a larger balloon than the bilateral instruments (25 mm or 30 mm, compared with 20 mm) so it can occupy the entire vertebral body and allow for reduction and curation of the void with a single access site. The technique was very easy to learn, and it offers many advantages for my patients.

Benefits to Patients
With this unilateral approach using a steerable osteotome and balloon catheter, I am able to reduce a severely compressed vertebral body to an improved height, just as I do with a bilateral approach. The advantages lie in limiting surgery to a single side as well as shortening the duration of the procedure.

Because a unilateral approach requires one-half of the incisions, there is less soft tissue and muscular injury. As a result, patients’ recovery periods can be shorter and less painful. My patients are generally up and out after the procedure. I watch them for two hours and send them home.

By performing balloon kyphoplasty unilaterally, I can now more safely and efficiently gain access to the vertebral body in those who have severe back arthrosis or scoliosis, which would take much longer with bilateral access. I can now choose an initial approach to the side with less bone damage, thus making the procedure less challenging for me and reducing the patient’s risk of injury.

The unilateral approach can also be much quicker than a bilateral approach, often requiring one-third less time. Less time means less radiation exposure to the patient, the technologist, and the physician. Because common significant comorbidities such as cardiac disease, diabetes, and pulmonary problems are seen in my older patients, less time on the operating table is always safer, and a shorter duration makes surgery less stressful for patients.

A final advantage is lower cost to hospitals and office-based labs. A unilateral procedure requires one balloon catheter and less operating room time. We get the same results as a bilateral approach, with added clinical advantages and significant cost savings.

Case Study
A 68-year-old woman with a history of osteoporosis presented to her doctor with pain and tenderness in her lower spine after a minor fall in her garden. The doctor ordered an MRI of the area, which showed an L1 vertebral compression fracture. The patient was referred to me for treatment.

The patient had severe COPD, which can complicate sedation, so conscious sedation was approached carefully. After local anesthesia, I used fluoroscopic imaging to make my incision, and I inserted the introducer needle using a right unilateral transpedicular approach. Next, the steerable osteotome was advanced into the vertebral body using anteroposterior projection and lateral imaging to the left anterior vertebral body location. The steerable high-pressure balloon was then advanced into the tract created by the steerable needle to reach the desired location in the vertebrae. I slowly inflated the balloon, creating the desired reduction and void within the vertebral body. I then removed the balloon catheter and inserted, through the initial needle, the bone cement delivery device, which was used to fill the void and the fracture site.

The patient was calm throughout the 20-minute procedure. The two-hour recovery period went smoothly, and the patient was uneventfully discharged to her home.

At our follow-up visit three weeks later, the patient’s incisions were healing nicely, and her spinal pain had diminished from nine to two on a 10-point pain scale. She was able to walk and sit comfortably and had already resumed normal activities. The unilateral approach to balloon kyphoplasty was beneficial to her in terms of time, pain, and recovery, reflecting a common result for this technology.

— David Shelley, MD, is an interventional radiologist and vascular specialist at Artery & Vein Specialists of Idaho and Bingham Memorial Hospital in Blackfoot, Idaho. He is a consultant for Merit Medical Systems.


1. Looker AC, Frenk SM; Centers for Disease Control and Prevention. Percentage of adults aged 65 and over with osteoporosis or low bone mass at the femur neck or lumbar spine: United States, 2005–2010. Published August 2015.

2. Looker AC, Sarafrazi Isfahani N, Fan B, Shepherd JA; Centers for Disease Control and Prevention. FRAX-based estimates of 10-year probability of hip and major osteoporotic fracture among adults aged 40 and over: United States, 2013 and 2014. Published March 28, 2017.

3. Waterloo S, Ahmed LA, Center JR, et al. Prevalence of vertebral fractures in women and men in the population-based Tromsø Study. BMC Musculoskelet Disord. 2012;13:3.