Lumbar Transpedicular Implant Failure: A Clinical and Surgical Challenge and Its Radiological Assessment

Abstract

Study DesignIt is a multicenter, controlled case study review of a big scale of pedicle-screw procedures from January 2000 to June 2010. The outcomes were compared to those with no implant failure.PurposeThe purpose of this study was to review retrospectively the outcome of 100 patients with implant failure in comparison to 100 control-patients, and to study the causes of failure and its prevention.Overview of LiteratureTranspedicular fixation is associated with risks of hardware failure, such as screw/rod breakage and/or loosening at the screw-rod interface and difficulties in the system assembly, which remain a significant clinical problem. Removal or revision of the spinal hardware is often required.MethodsTwo hundred patients (88 women, 112 men) were divided into 2 major groups, with 100 patients in group I (implant failure group G1) and 100 patients in group II (successful fusion, control group G2). We subdivided the study groups into two subgroups: subgroup a (single-level instrumented group) and subgroup b (multilevel instrumented group). The implant status was assessed based on intraoperative and follow-up radiographs.ResultsImplant failure in general was present in 36% in G1a, and in 64% in G1b, and types of implant failure included screw fracture (34%), rod fracture (24%), rod loosening (22%), screw loosening (16%), and failure of both rod and screw (4%). Most of the failures (90%) occurred within 6 months after surgery, with no reported cases 1 year postoperatively.ConclusionsWe tried to address the problem and study the causes of failure, and proposed solutions for its prevention.

Atemporal osseointegration: Early biomechanical stability through osseodensification

“…In clinical practice, orthopedic and dental implant complications have been reported to be as high as ∼34% and ∼8%, respectively. Of the 34% failure rate in orthopedic procedures, 16% were attributed to screw loosening during the healing period which is believed to be caused by failure to establish primary stability at the time of instrumentation, or lack of osseointegration during the healing period.…”

“…Failure of osseointegration continues to be a clinical challenge. Eldin et al determined that in a cohort of implant failures related to screw complications in the thoracolumbar, lumbar, or lumbosacral spine, were either due to screw fracture or screw loosening . Additionally, dental implant failure rates have been reported to be as high as ∼8%, due to excessive micromotion at the bone‐implant interface, as well as the inability to achieve functional loading .…”

Osseodensification for enhancement of spinal surgical hardware fixation

“…A recent review showed that approximately 50% of spinal implant failures were attributed to screw complications such as loosening (~16%) and fracture (~34%) (Eldin et al, 2014). In an attempt to prevent these type of failures, several studies have employed the use of hydroxyapatite (HA)-coated titanium alloy implants, since HA acts as a biomimetic material to promote osseointegration.…”

“…This can be explained by the phenomena observed within the fixture threads. Surgical instrumentation promotes initial bone remodeling that takes place in tandem with new bone formation (Coelho and Jimbo, 2014; Eldin et al, 2014). the decrease in BAFO seen at 3 weeks indicates a loss of bone fraction due to remodeling, and the regain of bone fraction observed at 6 weeks can be attributed to the production of woven bone occupying the healing chambers.…”

Predictive validity of preoperative CT scans and the risk of pedicle screw loosening in spinal surgery

“…Due to the significantly reduced integration of the screws at the screw-bone interface, screw loosening is more common in osteopenia and osteoporotic bones [25]. The previous investigations have demonstrated an incidence of screw loosening of up to 60 % in osteoporotic bones [7] compared to 1-27 % in nonosteoporotic patients treated with rigid posterior stabilization [12,13,24]. Based on this, newer techniques and materials have been developed to prevent this kind of complication [19].…”