Original ArticleEffect of Fenestrated Pedicle Screws with Cement Augmentation in Osteoporotic Patients Undergoing Spinal Fusion
Introduction
Osteoporosis, defined as a bone mineral density that is >2.5 standard deviations less than the mean for young healthy women, is a relative contraindication for instrumented fusion surgery owing to the decreased fixation strength of pedicle screws. This will manifest by increased screw pull out, pseudoarthrosis, and construct failure. An abundance of reported data have supported the correlation between pedicle screw stability and bone mineral density.1, 2, 3
The elderly population has a high incidence of osteoporosis and also constitute a large proportion of those undergoing spinal surgery.1, 2, 3, 4 Strategies to mitigate the risk of implant failure in elderly osteoporotic patients are, therefore, exceedingly important. Several strategies are available to mitigate the effects of osteoporosis, including treatment of the underlying condition with bone induction agents such as teriparatide, using larger diameter and longer length pedicle screws, the use of expandable screws, and the use of cement augmentation, frequently with polymethylmethacrylate.
Historically, cement injection into the vertebral body was first used to provide anterior column stabilization in the setting of metastatic disease.5 The first reported case of cement use was for treatment of a vertebral body hemangioma in France in 1984.5,6 Cadaveric studies involving the use of cement augmentation for pedicle screw stabilization were performed in the late 1980s and throughout the 1990s.7, 8, 9, 10, 11 These early cadaveric studies provided promising data on the potential for cement augmentation to improve pedicle screw purchase in the osteoporotic spine.
The first reported cases of cement augmentation for improved pedicle screw fixation as a salvage technique appeared in the late 1990s.12, 13, 14 The initial approaches for cement augmentation were performed by cement injection through a tapped pedicle screw tract.15 With the advent of minimally invasive spine surgery16 and the introduction of cannulated screws, reports of the use of fenestrated screws for cement augmentation appeared in the 2000s.17,18 Fenestrated screws have the theoretical advantage of cement penetration into the vertebral body directly around the screw, with less opportunity for cement extravasation through pedicle breaches.15
The use of cement augmentation, however, is not without risk. Cement augmentation has been associated with several neurologic and cardiopulmonary complications. Specifically, cement extravasation into the epidural space or neural foramen can cause neurologic injury. The cement can also embolize into the venous system via the epidural veins and travel to the right atrium and pulmonary arteries, potentially causing right heart strain or respiratory failure.19,20
The goal of the present review was to systematically identify and analyze the reported data on cement-augmented fenestrated pedicle screws, with specific attention to the biomechanics, outcomes, and complications.
Section snippets
Literature Search and Inclusion Criteria
We conducted a systematic review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.21 Using the PubMed database, we first identified relevant studies using the search terms “cement” AND “pedicle screw” AND “osteoporosis” that had been reported through March 31, 2020. We elected to use the PubMed database because of its broad accessibility, author familiarity, and access to ahead-of-print citations with the most up-to-date reported information.
Study Selection
The database search identified 120 studies. After title and abstract review, 81 studies were excluded, and the full text of 39 reports was reviewed, which resulted in the exclusion of another 16 studies. After a review of the references, another 2 studies were included. The reason for study exclusion included non-English language, publication before 2000, use of cement without fenestrated pedicle screws, lack of cement use, nonhuman study, technical report, and individual case report. A total
Discussion
Given the increasingly elderly population with symptomatic degenerative disease, the ability to treat patients with osteoporosis is essential. The introduction of fenestrated pedicle screws has facilitated the broader use of cement augmentation in spinal fusion, especially because cement augmentation can now be performed using minimally invasive surgical techniques.
One of the greatest concerns with osteoporotic bone is the loss of screw fixation and subsequent pull out with construct failure.
Conclusions
The use of cement-augmented fenestrated pedicle screws is a recent innovation that has been shown to improve screw fixation strength in osteoporotic bone. The results from the included studies have suggested that cement-augmented fenestrated pedicle screws have an adequate safety profile. However, extravasation of cement can be common. Despite this complication, the patients with cement extravasation were largely asymptomatic according to most reports and the extravasation was not clinically
CRediT authorship contribution statement
Yamaan S. Saadeh: Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Writing - original draft, Writing - review & editing. Kevin N. Swong: Data curation, Formal analysis, Investigation, Methodology, Project administration, Resources, Software, Supervision, Validation, Writing - original draft, Writing - review & editing. Timothy J. Yee: Formal analysis, Validation, Writing - original draft, Writing - review &
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Cited by (13)
Discordance in lumbar bone mineral density measurements by quantitative computed tomography and dual-energy X-ray absorptiometry in postmenopausal women: a prospective comparative study
2023, Spine JournalCitation Excerpt :As trabecular bone is the main contributor to the strength of the screw-bone interface in the vertebral body, it is of greater clinical value to focus on trabecular BMD than that of the entire vertebral body [9]. Trabecular BMD of a single vertebral body can provide useful surgical planning information [10], as preoperative BMD at a specific level can help to predict the benefits of cement augmentation [11,12]. Regional QCT-derived BMD was confirmed to predict the strength of pedicle screw fixation, as well as cage subsidence following lumbar interbody fusion [13–15].
Postoperative and Intraoperative Cement Augmentation for Spinal Fusion
2022, World NeurosurgeryCitation Excerpt :One of these techniques is cement augmentation (CA) of pedicle screws and the adjacent vertebral body. A variety of intraoperative CA techniques have been described, including a transpedicular vertebroplasty,11 kyphoplasty,12 pedicle screw coating before insertion,13 and injection of cement through cannulated/fenestrated screws.10,14 At our institution, a more commonly used technique is postoperative CA, completed by interventional radiology.
Oblique lateral interbody fusion: The fundamentals for practice
2022, Seminars in Spine SurgeryCitation Excerpt :However, it should be noted that cage subsidence (CS) rates can be lessened in patients with osteoporosis and osteopenia when OLIF is combined with pedicle screw rod fixation (PSRF).31 Additionally, cement augmentation via fenestrated pedicle screw fixation has been show to improve patient reported outcome (VAS, OSI) scores and reduce screw pull-out in patients with underlying osteoporosis.32 OLIF complications are primarily related to exposure and endplate preparation.
Comparison of cement-augmented pedicle screw and conventional pedicle screw for the treatment of lumbar degenerative patients with osteoporosis
2024, European Journal of Orthopaedic Surgery and Traumatology
Conflict of interest statement: The authors declare that the article content was composed in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.