Effectiveness and reliability of cannulated fenestrated screws augmented with polymethylmethacrylate cement in the surgical treatment of osteoporotic vertebral fractures

Cement Leakage after Augmentation of Osteoporotic Vertebral Bodies

Der Zementaustritt ist die häufigste Komplikation bei der Zementaugmentation von Wirbelkörpern. In der vorliegenden Studie wurden die Zementaustrittsraten bei Zementaugmentationen an der Wirbelsäule untersucht und potenzielle Risikofaktoren für einen Zementaustritt identifiziert.Es wurden 140 Fälle von 131 Patienten und Patientinnen und 9 Verstorbenen ausgewertet. Insgesamt wurden 258 zementaugmentierte Wirbelkörper untersucht. Die Daten dafür stammen aus den Krankenhausdokumentationen von 131 Patienten und Patientinnen, die sich in 2 orthopädisch-unfallchirurgischen Kliniken in der BRD solchen Operationen unterzogen, sowie aus den Untersuchungen von 9 Sterbefällen im Institut für Rechtsmedizin der Universitätsklinikums Hamburg-Eppendorf.Zementaustritte wurden in 64 der 140 Fälle (45,7%) ermittelt. Lokale Zementaustritte waren mit 73,4% (n = 47) die häufigste Austrittsart. Venöse Austritte wurden in 15 Fällen (23,4%) und Lungenzementembolisationen in 2 Fällen (3,1%) evaluiert. Innerhalb des Kollektivs der retrospektiv untersuchten Fälle (n = 131) erlitt lediglich 1 Patient (0,8%) einen symptomatischen Zementaustritt. Als Risikofaktoren für Zementaustritte konnten Zementaugmentationen von Frakturen an Lendenwirbelkörpern sowie eine hohe applizierte Zementmenge identifiziert werden.Sowohl die Daten in der assoziierten Literatur als auch die Ergebnisse dieser Arbeit belegen eine hohe Inzidenz von Zementaustritten nach Wirbelkörperaugmentationen. Trotz des geringen prozentualen Anteils symptomatischer Fälle sollten bei der Planung und Durchführung von Zementaugmentationen an Wirbelkörpern die möglichen Einflussfaktoren für einen Zementaustritt berücksichtigt und in die OP-Planung einbezogen werden.

The Clinical Use of Osteobiologic and Metallic Biomaterials in Orthopedic Surgery: The Present and the Future

As the area and range of surgical treatments in the orthopedic field have expanded, the development of biomaterials used for these treatments has also advanced. Biomaterials have osteobiologic properties, including osteogenicity, osteoconduction, and osteoinduction. Natural polymers, synthetic polymers, ceramics, and allograft-based substitutes can all be classified as biomaterials. Metallic implants are first-generation biomaterials that continue to be used and are constantly evolving. Metallic implants can be made from pure metals, such as cobalt, nickel, iron, or titanium, or from alloys, such as stainless steel, cobalt-based alloys, or titanium-based alloys. This review describes the fundamental characteristics of metals and biomaterials used in the orthopedic field and new developments in nanotechnology and 3D-printing technology. This overview discusses the biomaterials that clinicians commonly use. A complementary relationship between doctors and biomaterial scientists is likely to be necessary in the future.

Cardiopulmonary Cement Embolism Following Cement-Augmented Pedicle Screw Fixation: A Narrative Review

Fixation using cement-augmented pedicle screws (CAPS) is being increasingly performed. However, CAPS-associated cement leakage is a critical problem that can lead to cardiopulmonary cement embolism (CPCE). This narrative review aimed to explore the incidence of and risk factors and treatment strategies for CPCE and cement leakage-related complications after CAPS fixation. Data were extracted from each article, including characteristics of CPCE after CAPS fixation (incidence, location, diagnostic method and criteria, treatment, and outcome and prognosis). Overall, 28 case series and 14 case reports that met the inclusion criteria were included. Of the 1974 cases included in the review, CPCE was noted in 123, symptomatic CPCE in 35, and death in six, respectively. The frequencies of PCE and symptomatic PCE after CAPS fixation were 6% (range: 0-28.6%) and 1.3% (range: 0-26%), respectively. The range of frequencies of PCE and symptomatic PCE after CAPS fixation may have been wide because the definition of CPCE and data collection methods differed among the reports analyzed. Since PCE due to large cement emboli may be primarily related to the surgical technique, improved technique, such as minimizing the number of CAPSs by injecting low-volume high-viscosity cement at low velocity and pressure, and careful observation of cement leakage during CAPS insertion may reduce PCE associated with cement leakage. Spinal surgeons should pay more attention to the occurrence of CPCE during and after CAPS insertion, which can cause serious complications in some patients.

Biomechanical Comparison and Three-Dimensional Analysis of Cement Distribution Patterns for Different Pedicle Screw Designs

The purpose of this study to explore strategies for reducing cement leakage during cement-augmented pedicle screw fixation, we compared the cement distribution patterns and biomechanical strengths of different types of cement-augmented fenestrated screws and traditional cement-augmented techniques. We compared five screw groups in this study: (1) Cannulated screws (Cann); (2) distal one-hole screws (D1); (3) distal two-hole screws (D2); (4) middle two-hole screws (M2); and (5) traditional screws with a traditional cement injection technique (Trad). The screws were inserted into cancellous bone blocks using a controlled, adequate cement injection pressure (1.6–2.0 kg), and an appropriate cement viscosity. Center to screw tip distance, three-dimensional distribution, and pull-out strength for cement were compared between groups. The average distance between the cement center and the screw tip was highest in the M2 group, suggesting a higher risk of cement leakage into the spinal canal. The Trad group had the highest migration distance in the z-axis, also reflecting a higher risk of leakage into the spinal canal. The D1 group had the highest pull-out strength ( $253\pm 48.82\text{N}$ and $797\pm 58.31\text{N}$ ) in bone blocks representing different degrees of osteoporosis, and the D2 group had the second highest pull-out strength in the severe osteoporosis model. Overall, D1 screws appeared to be the best option for optimizing biomechanical function and minimizing the risk of cement leakage into the spinal canal in patients with osteoporotic bone undergoing spinal surgery.

Comparison of clinical effectiveness of fenestrated and conventional pedicle screws in patients undergoing spinal surgery: a systematic review and meta-analysis

INTRODUCTION

Pedicle screws are commonly used for spinal procedures for fusion stability, which is particularly important in osteoporotic patients, who are at an increased risk of requiring revision procedures.

AREAS COVERED

A systematic review and meta-analysis were conducted to compare clinical effectiveness of conventional pedicle screws (CPS) vs fenestrated pedicle screws (FPS) in patients undergoing spinal surgery. Primary outcomes included screw loosening, revision surgeries (involving an implant) and reoperations (not involving intervention on an implant) in patients treated with CPS vs FPS, sub-stratified by with and without osteoporosis. Secondary outcomes included changes in pain scores. Forty-eight studies with 8,302 patients were included, with 1,565 (19.18%) treated with FPS and 6,710 (80.82%) treated with CPS. FPS was associated with a lower risk of screw loosening (p = 0.001) vs CPS. In the general population, there was a non-significant trend of lower revision rate, but no difference in reoperation rate, between patients treated with FPS vs CPS. In osteoporotic patients, revision rates were significantly lower for FPS vs CPS (p = 0.009).

EXPERT OPINION

This review suggests that FPS are effective for surgical fixation and reduce rates of screw loosening, and in osteoporotic patients, revision surgeries, compared to CPS.