Orthopaedic surgeons at Penn Medicine have introduced Curvafix, an advanced fixation device for the treatment of pelvic fragility fractures. Penn Medicine is one of only two health systems in the Philadelphia region to do so.
Fragility fractures of the pelvis (FFPs) have an increasing incidence with aging, and are thus becoming more and more common in the US population. The pelvis connects the spine to the lower extremities and sees a tremendous amount of mechanical load, making it prone to fractures. The risk of fracture is compounded when these bones are further attenuated by diminished bone density as a result of osteoporosis, radiation therapy, vitamin D deficiency, or chronic steroid use, among other factors. As a result, the pelvis is fragile and prone to fracture following minor ground level falls or simple overuse.
Patients experiencing FFPs typically present with low back pain centered over the sacrum and describe difficulty with walking or sitting. Most patients visit their PCP or another non-operative clinician, and conservative care is recommended, such as bed rest, pain medication, and mobility assistance. This often causes symptoms to worsen and may lead to prolonged inpatient stays, loss of independence, high nursing home admittance, high rates of mortality, and a significant financial burden for health systems.
Repair of pelvic fragility fractures is complicated by the curved structure of the pelvis, and the weightbearing and ambulatory forces involved in pelvic function. Pelvic fractures are classified into four categories of ascending severity by location and degree of pelvic ring injury, and each is a determinant of treatment approach. Generally, some type of fixation is recommended for type III and IV fractures.
CURVAFIX: A Novel Approach to Pelvic Fragility Fractures
Rigid fixation with screws is a common approach to type III and IV fractures of the pubic, iliac and acetabular bones. However, straight rigid screws do not fit well within the curved scalloped bone of the pelvis, leading to the use of short screws, screws being malpositioned, or screw loosening especially in osteoporotic bone.
To address this issue, orthopedic surgeons at Penn Medicine have introduced the percutaneous Curvafix device (Figure 1), a novel intramedullary screw comprising linked components that conform to the irregular bony curvature of the pelvis and offer greater flexibility on the starting point/trajectory than is possible for a straight screw.
Other key advantages of Curvafix include:
- A locking mechanism that ensures stabilization of pelvic bone fractures, allowing for near immediate weightbearing
- Shorter surgical time, a smaller incision, less postoperative pain and faster recovery, compared to other invasive alternatives increasing the likelihood of early mobility and better outcomes
- Unique approaches to the pelvis to provide stability that were historically not possible
- A steerable guidewire and reamers that provide tactile feedback and consequent confirmation of containment within the safe osseous pathway.
Case Study 1
Mrs. G, a 70-year-old female recently diagnosed with metastatic pancreatic cancer presented to the Penn Orthopaedic Trauma and Fracture Program with acute new onset of lower back pain. She was receiving chemotherapy, participating in a drug therapy trial, and had recently received radiation therapy. She had no history of acute trauma to the pelvic or acetabular region.
Figure 1 - Bilateral insufficiency fractures in an oncology patient.
Magnetic resonance imaging revealed bilateral fragility fractures of Mrs. G’s pelvis, with those occurring on the left more prevalent than the right (Figure 1). Following radiology and oncology review, it was concluded that the fractures were not metastatic in nature, but likely a consequence of insufficiency arising from the chemotherapeutic agents and/or radiation therapy.
To address these issues, Mrs. G began conservative care with a walker, and her regimen was altered to include vitamin D. Moreover, methotrexate was dropped from her chemotherapy regimen.
Two months post referral however, Mrs. G returned with increasing pain focal to the lower back that was distinctly different from that she had previously experienced, and reported a greater dependency on her walker. A consultation with Mrs. G, her family, and oncologist reached accord in a decision to stabilize the posterior pelvic ring for palliative measures and increasing functionality.
Figure 2 - CurvaFix IM Implant (170 mm in length) placed in the upper sacral segment the pelvis, followed by a transiliac-transsacral CurvaFix IM Implant (150 mm in length) in S2.
In an outpatient procedure, a CurvaFix IM Implant (170 mm in length) was placed in the upper sacral segment of Mrs. M’s pelvis, followed by a transiliac-transsacral CurvaFix IM Implant (150 mm in length) in S2 (Figure 2). Mrs. M was discharged home weight bearing as tolerated with a walker, with venous thromboembolism prophylaxis and pain medications.
At 3 weeks, Mrs. M reported no pain in the pelvis, satisfaction with the procedure, and improvement in quality of life. Her posture was improved, and she was able to walk with a walker, limited only by the known chronic back pain.
Case Study 2
Clare, a 70-year-old woman, was referred to the Penn Orthopaedic Trauma and Fracture Program from an outside medical center to address a series of fragility fractures, including a complete non-displaced Denis type 1 right sacral fracture and bilateral superior and inferior pubic ramus fractures sustained in a vehicular accident (Figure 3) in which she also fractured her right surgical neck humerus.
Clare was taken to the OR for screw fixation at S1 and S2 at the referring institution, but the procedure was suspended intra-op when she was found on imaging to have a dysmorphic sacrum and thus, an incapacity for safe screw placement.
Figure 3 - Fragility fractures, including complete non-displaced Denis type 1 right sacral fracture and bilateral superior and inferior pubic ramus fractures in a 70-year-old woman.
A breast cancer survivor, Clare had advanced osteoporosis, but appeared otherwise relatively healthy. She was an independent ambulator without assistive devices prior to her accident. She had no bowel/bladder dysfunction, and no radicular, cardiovascular or pulmonary issues. On examination following her admission to Penn Presbyterian Medical Center, where she was medically optimized, Clare’s lower extremities were found to be unremarkable outside of abrasions to her right lateral thigh. Moreover, she had full bilateral active and passive ROM of hips, knees, ankles, and toes.
The morbidity of nonoperative management of pelvic ring fractures in the elderly being a consideration, the decision was made to surgically intervene for Clare’s pelvis using CurvaFix implants. With her family present, she was apprised by surgeon Derek Donegan, MD, of the potential risks of surgery, including infection, bleeding, neurovascular injury and anesthesia concerns, among other factors, and after her questions were answered, provided informed consent to proceed.
The Procedure: Following normal preoperative procedures, an examination under anesthesia revealed a grossly unstable pelvis. At this point, attention was turned to placing the lower sacral segment trans-iliac-trans-sacral screw. This involved threading a guide wire across the right ilium, right sacroiliac joint, sacrum, left sacroiliac joint, and left ilium. A path was then opened over the guide wire, fluoroscopically confirmed and measured, and the appropriate length Curvafix (140mm) screw placed and locked. Similar procedures were then performed to address the superior and inferior pubic ramus fractures, placing and locking screws of 110 mm and 100 mm (Figure 4).
Figure 4 - Curvafix (140mm) screw placed and locked at the sacral region, with screws of 110 mm and 100 mm at the superior and inferior pubic ramus fractures.
A final fluoroscopic evaluation revealed good restoration of the pelvic anatomy with appropriately placed hardware, an assessment confirmed by intra-operative CT scan. Clare’s pelvis was then stressed and its stability confirmed, at which point all wounds were irrigated thoroughly and closed.
Clare was designated weight bearing as tolerated immediately postoperatively, and was walking with physical therapy on the day of surgery; she left the hospital on postoperative day six. She also underwent surgical fixation of her right proximal humerus to allow her to mobilize. At two weeks, she was at home walking with a walker with a significant improvement in pain.
About the Penn Orthopaedic Trauma and Fracture Program
The Penn Orthopaedic Trauma and Fracture Program is the largest and most complete program in the Philadelphia region, with extensive capabilities for treating all musculoskeletal fractures, traumatic injuries and related complications.
In collaboration with the Penn Trauma Center, a Level 1 regional resource trauma center, our patients benefit from a multidisciplinary approach where more than one expert is involved in developing personalized care plans.
Our goal is to help patients return to normal activities as quickly as possible with the most appropriate treatment and rehabilitation for their particular orthopaedic injury or fracture.
Performing CurvaFix Implantation at Penn Medicine
Samir Mehta, MD
Chief, Division of Orthopaedic Trauma and Fracture Care
Medical Director, Orthopaedic Clinical Research
Co-Director, Penn Orthoplastic Limb Salvage Center
Associate Professor of Orthopaedic Surgery
Derek James Donegan, MD
Associate Professor of Orthopaedic Surgery
Location
Penn Musculoskeletal Center - University City, 7th Floor
Penn Medicine University City
7th Floor
3737 Market Street
Philadelphia, PA 19104
A facility of Penn Presbyterian Medical Center