title: Cement leakage in pedicle screw augmentation: a prospective analysis of 98 patients and 474 augmented pedicle screws.
abstract: OBJECTIVE Loosening and pullout of pedicle screws are well-known problems in pedicle screw fixation surgery. Augmentation of pedicle screws with bone cement, first described as early as 1975, increases the pedicle-screw interface and pullout force in osteoporotic vertebrae. The aim of the present study was to identify cement leakage and pulmonary embolism rates in a large prospective single-center series of pedicle screw augmentations. METHODS All patients who underwent cement-augmented pedicle screw placement between May 2006 and October 2010 at the authors' institution were included in this prospective cohort study. Perivertebral cement leakage and pulmonary cement embolism were evaluated with a CT scan of the area of operation and with a radiograph of the chest, respectively. RESULTS A total of 98 patients underwent placement of cement-augmented pedicle screws; 474 augmented screws were inserted in 237 vertebrae. No symptomatic perivertebral cement leakage or symptomatic pulmonary cement embolism was observed, but asymptomatic perivertebral cement leakage was seen in 88 patients (93.6%) and in 165 augmented vertebrae (73.3%). Cement leakage most often occurred in the perivertebral venous system. Clinically asymptomatic pulmonary cement embolism was found in 4 patients (4.1%). CONCLUSIONS Perivertebral cement leakage often occurs in pedicle screw augmentation, but in most cases, it is clinically asymptomatic. Cement augmentation should be performed under continuous fluoroscopy to avoid high-volume leakage. Alternative strategies, such as use of expandable screws, should be examined in more detail for patients at high risk of screw loosening.
authors.affiliation: Department of Neurosurgery, University Medicine Greifswald.
authors.forename: Jan U
authors.initials: JU
authors.lastname: Mueller
authors.affiliation: Department of Neurosurgery, University Medicine Greifswald.
authors.forename: Joerg
authors.initials: J
authors.lastname: Baldauf
authors.affiliation: Department of Neurosurgery, University Medicine Greifswald.
authors.forename: Sascha
authors.initials: S
authors.lastname: Marx
authors.affiliation: Department of Radiology and Neuroradiology, University Medicine Greifswald, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Kirsch
authors.affiliation: Department of Neurosurgery, University Medicine Greifswald.
authors.forename: Henry W S
authors.initials: HW
authors.lastname: Schroeder
authors.affiliation: Department of Neurosurgery, University Medicine Greifswald.
authors.forename: Dirk T
authors.initials: DT
authors.lastname: Pillich
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001843:Bone Cements / Q000009:adverse effects* / Q000627:therapeutic use*; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000009:adverse effects* / Q000379:methods*; D065289:Pedicle Screws; D011183:Postoperative Complications / Q000000981:diagnostic imaging; D011446:Prospective Studies; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging / Q000209:etiology; D016103:Spinal Fractures / Q000601:surgery*; D013131:Spine / Q000601:surgery; D014057:Tomography, X-Ray Computed
chemical_list: D001843:Bone Cements
keywords: ASIA = American Spinal Injury Association; PMMA = polymethylmethacrylate; VAS = visual analog scale; cement augmentation; cement leakage; pedicle screw; technique