Pedicle screw loosening in dynamic stabilization: incidence, risk, and outcome in 126 patients

Wu, Jau Ching; Huang, Wen Cheng; Tsai, Hsiao Wen; Ko, Chin Chu; Wu, Chih-Cheng; Tu, Tsung Hsi; Cheng, Henrich

doi:10.3171/2011.7.focus11125

Cited by 139 publications

(149 citation statements)

References 31 publications

(27 reference statements)

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“…Previous single-treatment-arm studies of the Dynesys system also found radiographic evidence of screw loosening in 1.2%-19.8% of patients and 2.8%-4.7% of screws, and clinical deterioration resulting from the loosening of screws and necessitating revision surgery occurred in 0%-1.2% of patients. 16,17,26,30,31,34 Therefore, the risk of screw loosening and revision surgery after PDS using Dynesys seems to be considerably low.…”

Section: Evaluation Of Possible Disadvantages Of the Dynesys Systemmentioning

confidence: 99%

Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: a clinical and radiological outcomes-based meta-analysis

Lee

Jahng

Hyun

et al. 2016

FOC

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OBJECTIVE The Dynesys, a pedicle-based dynamic stabilization (PDS) system, was introduced to overcome the drawbacks of fusion procedures. Nevertheless, the theoretical advantages of PDS over fusion have not been clearly confirmed. The aim of this study was to compare clinical and radiological outcomes of patients who underwent PDS using the Dynesys system with those who underwent posterior lumbar interbody fusion (PLIF). METHODS The authors searched PubMed, Embase, Web of Science, and the Cochrane Database. Studies that reported outcomes of patients who underwent PDS or PLIF for the treatment of degenerative lumbar spinal disease were included. The primary efficacy end points were perioperative outcomes. The secondary efficacy end points were changes in the Oswestry Disability Index (ODI) and back and leg pain visual analog scale (VAS) scores and in range of motion (ROM) at the treated and adjacent segments. A meta-analysis was performed to calculate weighted mean differences (WMDs), 95% confidence intervals, Q statistics, and I2 values. Forest plots were constructed for each analysis group. RESULTS Of the 274 retrieved articles, 7 (which involved 506 participants [Dynesys, 250; PLIF, 256]) met the inclusion criteria. The Dynesys group showed a competitive advantage in mean surgery duration (20.73 minutes, 95% CI 8.76–32.70 minutes), blood loss (81.87 ml, 95% CI 45.11–118.63 ml), and length of hospital stay (1.32 days, 95% CI 0.23–2.41 days). Both the Dynesys and PLIF groups experienced improved ODI and VAS scores after 2 years of follow-up. Regarding the ODI and VAS scores, no statistically significant difference was noted according to surgical procedure (ODI: WMD 0.12, 95% CI −3.48 to 3.72; back pain VAS score: WMD −0.15; 95% CI −0.56 to 0.26; leg pain VAS score: WMD −0.07; 95% CI −0.47 to 0.32). The mean ROM at the adjacent segment increased in both groups, and there was no substantial difference between them (WMD 1.13; 95% CI −0.33 to 2.59). Although the United States is the biggest market for Dynesys, no eligible study from the United States was found, and 4 of 8 enrolled studies were performed in China. The results must be interpreted with caution because of publication bias. During Dynesys implantation, surgeons have to decide the length of the spacer and cord pretension. These values are debatable and can vary according to the surgeon's experience and the patient's condition. Differences between the surgical procedures were not considered in this study. CONCLUSIONS Fusion still remains the method of choice for advanced degeneration and gross instability. However, spinal degenerative disease with or without Grade I spondylolisthesis, particularly in patients who require a quicker recovery, will likely constitute the main indication for PDS using the Dynesys system.

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Section: Evaluation Of Possible Disadvantages Of the Dynesys Systemmentioning

confidence: 99%

Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: a clinical and radiological outcomes-based meta-analysis

Lee

Jahng

Hyun

et al. 2016

FOC

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“…Pedicle screws require initial rigid fixation and longevity to stabilise the spine while the fusion mass forms. This procedure is broadly successful with low rates of screw loosening for standard screws (1-3) and increased rates for dynamic systems (4)(5)(6)(7). Screw loosening is a concern, with radiolucency around screws detrimental to fixation (8) and often warranting revision surgery (9).…”

Section: Introductionmentioning

confidence: 99%

The contribution of the cortical shell to pedicle screw fixation

Pelletier¹,

Bertollo²,

Al-Khawaja³

et al. 2017

J. Spine Surg.

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Background: A pedicle screw insertion technique known as "hubbing" involves the removal of cortical bone around the screw insertion with the aim of improving fixation and decreasing screw loosening.However, the efficacy of this procedure relative to bone density and early loading have not been fully explored. The purpose of this study is to establish the contribution of the cortical layer (hubbing), cancellous density, early loading (toggling) in an idealised model. This is an in vitro laboratory study.Methods: Synthetic bone blocks with cancellous bulk and a simulated cortical shell were implanted with 6.5 mm pedicle screws. Three key variables were evaluated in this study; density of the simulated bone (10-20 lb/ft 3 ), toggling (±0.5 mm for 10,000 cycles), and the presence or absence of the surrounding cortex (hubbing). Pullout testing after toggling was performed to determine maximum load, stiffness and energy.Results were analyzed to assess interaction and main effects.Results: Removal of the cortex decreased the pullout loads by approximately 1,100 N after toggling.Toggling in the presence of the cortical shell had no effect. However, once the cortical shell is removed damage to the weaker cancellous bone accumulates and further compromises the fixation.Conclusions: The addition of a cortical layer in the Sawbone model is significant and provides a more realistic model of load sharing. The cortex plays a considerable role in the protection of underlying cancellous bone as well as contributing to initial pullout strength. The results of this study demonstrate a negative synergistic effect when both toggling and hubbing are applied to the weaker bone.

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“…Because of the presence of nonspecific postoperative changes and metal-related imaging artefacts, interpretation of CT images is often not straightforward and is inconclusive. Thus, whether surgical reintervention is indicated based on conventional imaging may prove difficult to ascertain [5,6].…”

Section: Introductionmentioning

confidence: 99%

Accuracy of bone SPECT/CT for identifying hardware loosening in patients who underwent lumbar fusion with pedicle screws

Hudyana

Maes

Vandenberghe

et al. 2015

Eur J Nucl Med Mol Imaging

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Background The aim of this retrospective study was to evaluate the accuracy of bone SPECT (single photon emission computed tomography)/CT (computed tomography) in diagnosing loosening of fixation material in patients with recurrent or persistent back pain that underwent lumbar arthrodesis with pedicle screws using surgery and clinical follow-up as gold standard Methods A total of 48 patients (median age 49 years, range 21-81 years; 17 men) who had undergone lumbar spinal arthrodesis were included in this retrospective analysis. SPECT/ CT results were compared to the gold standard of surgical evaluation or clinical follow-up. Positive SPECT/CT results were considered true positives if findings were confirmed by surgery or if clinical and other examinations were completely consistent with the positive SPECT/CT finding. They were considered false positives if surgical evaluation did not find any loose pedicle screws or if symptoms subsided with non-surgical therapy. Negative SPECT/CT scans were considered true negatives if symptoms either improved without surgical intervention or remained stable over a minimum follow-up period of 6 months. Negative SPECT/CT scans were determined to be false negatives if surgery was still required and loosening of material was found.Results The median length of time from primary surgery to bone SPECT/CT referral was 29.5 months (range 12-192 months). Median follow-up was 18 months (range 6-57) for subjects who did not undergo surgery. Thirteen of the 48 patients were found to be positive for loosening on bone SPECT/CT. Surgical evaluation (8 patients) and clinical follow-up (5 patients) showed that bone SPECT/CT correctly predicted loosening in 9 of 13 patients, while it falsely diagnosed loosening in 4 patients. Of 35 negative bone SPECT/CT scans, 12 were surgically confirmed. In 18 patients, bone SPECT/CT revealed lesions that could provide an alternative explanation for the symptoms of pain (active facet degeneration in 14 patients, and disc and sacroiliac osteodegeneration in 7 patients and 1 patient, respectively). Overall sensitivity and specificity for the detection of loosening were 100 % and 89.7 %, respectively. The positive and negative predictive values were 69 % and 100 %, respectively. Conclusions This retrospective analysis suggests that bone SPECT/CT bone is a highly sensitive and specific tool for the exclusion of screw loosening in patients who present with recurrent low back pain after having undergone lumbar arthrodesis. In addition, it can identify other potential causes of recurrent low back pain in this patient population.

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Pedicle screw loosening in dynamic stabilization: incidence, risk, and outcome in 126 patients

Cited by 139 publications

References 31 publications

Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: a clinical and radiological outcomes-based meta-analysis

Dynamic stabilization using the Dynesys system versus posterior lumbar interbody fusion for the treatment of degenerative lumbar spinal disease: a clinical and radiological outcomes-based meta-analysis

The contribution of the cortical shell to pedicle screw fixation

Accuracy of bone SPECT/CT for identifying hardware loosening in patients who underwent lumbar fusion with pedicle screws

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