Hounsfield unit of screw trajectory as a predictor of pedicle screw loosening after single level lumbar interbody fusion

OBJECTIVE Cortical screw–rod (CSR) fixation has emerged as an alternative to the traditional pedicle screw–rod (PSR) fixation for posterior lumbar fixation. Previous studies have concluded that CSR provides the same stability in cadaveric specimens as PSR and is comparable in clinical outcomes. However, recent clinical studies reported a lower incidence of radiographic and symptomatic adjacent-segment degeneration with CSR. No biomechanical study to date has focused on how the adjacent-segment mobility of these two constructs compares. This study aimed to investigate adjacent-segment mobility of CSR and PSR fixation, with and without interbody support (lateral lumbar interbody fusion [LLIF] or transforaminal lumbar interbody fusion [TLIF]). METHODS A retroactive analysis was done using normalized range of motion (ROM) data at levels adjacent to single-level (L3–4) bilateral screw–rod fixation using pedicle or cortical screws, with and without LLIF or TLIF. Intact and instrumented specimens (n = 28, all L2–5) were tested using pure moment loads (7.5 Nm) in flexion, extension, lateral bending, and axial rotation. Adjacent-segment ROM data were normalized to intact ROM data. Statistical comparisons of adjacent-segment normalized ROM between two of the groups (PSR followed by PSR+TLIF [n = 7] and CSR followed by CSR+TLIF [n = 7]) were performed using 2-way ANOVA with replication. Statistical comparisons among four of the groups (PSR+TLIF [n = 7], PSR+LLIF [n = 7], CSR+TLIF [n = 7], and CSR+LLIF [n = 7]) were made using 2-way ANOVA without replication. Statistical significance was set at p < 0.05. RESULTS Proximal adjacent-segment normalized ROM was significantly larger with PSR than CSR during flexion-extension regardless of TLIF (p = 0.02), or with either TLIF or LLIF (p = 0.04). During lateral bending with TLIF, the distal adjacent-segment normalized ROM was significantly larger with PSR than CSR (p < 0.001). Moreover, regardless of the types of screw-rod fixations (CSR or PSR), TLIF had a significantly larger normalized ROM than LLIF in all directions at both proximal and distal adjacent segments (p ≤ 0.04). CONCLUSIONS The use of PSR versus CSR during single-level lumbar fusion can significantly affect mobility at the adjacent segment, regardless of the presence of TLIF or with either TLIF or LLIF. Moreover, the type of interbody support also had a significant effect on adjacent-segment mobility.

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A Radiological Comparison of Anterior Fusion Rates in Anterior Lumbar Interbody Fusion

Global Spine Journal ◽

10.1055/s-0032-1329892 ◽

2012 ◽

Vol 2 (4) ◽

pp. 195-206 ◽

Cited By ~ 11

Author(s):

M. J. H. McCarthy ◽

L. Ng ◽

G. Vermeersch ◽

D. Chan

Keyword(s):

Pedicle Screw ◽

Interbody Fusion ◽

Posterior Instrumentation ◽

Anterior Lumbar Interbody Fusion ◽

Posterior Fusion ◽

Posterior Fixation ◽

Anterior Fusion ◽

Lumbar Interbody Fusion ◽

Anterior Surgery ◽

Single Level

Aim To compare anterior fusion in standalone anterior lumbar interbody fusion (ALIF) using cage and screw constructs and anterior cage–alone constructs with posterior pedicle screw supplementation but without posterior fusion. Methods Eighty-five patients underwent single- or two-level ALIF procedure for degenerative disk disease or lytic spondylolisthesis (SPL). Posterior instrumentation was performed without posterior fusion in all cases of lytic SPL and when the anterior cage used did not have anterior screw through cage fixation. Results Seventy (82%) patients had adequate radiological follow-up at a mean of 19 months. Forty patients had anterior surgery alone (24 single level and 16 two levels) and 30 had front-back surgery (15 single level and 15 two levels). Anterior locked pseudarthrosis was only seen in the anterior surgery–alone group when using the STALIF cage (Surgicraft, Worcestershire, UK) (37 patients). This occurred in five of the single-level surgeries (5/22) and nine of the two-level surgeries (9/15). Fusion was achieved in 100% of the front-back group and only 65% (26/40) of the anterior surgery–alone group. Conclusion Posterior pedicle screw supplementation without posterolateral fusion improves the fusion rate of ALIF when using anterior cage and screw constructs. We would recommend supplementary posterior fixation especially in cases where more than one level is being operated.

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282. Vertebral Hounsfield unit is a better predictor of pedicle screw loosening than the t-score of DXA in patients with lumbar degenerative diseases

The Spine Journal ◽

10.1016/j.spinee.2019.05.298 ◽

2019 ◽

Vol 19 (9) ◽

pp. S137-S138

Author(s):

Da Zou ◽

Weishi Li

Keyword(s):

Pedicle Screw ◽

Hounsfield Unit ◽

Degenerative Diseases ◽

Screw Loosening ◽

T Score ◽

Lumbar Degenerative Diseases ◽

Pedicle Screw Loosening

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Comparative Study of Cortical Bone Trajectory-Pedicle Screw (Cortical Screw) Versus Conventional Pedicle Screw in Single-Level Posterior Lumbar Interbody Fusion: A 2-Year Post Hoc Analysis from Prospectively Randomized Data

World Neurosurgery ◽

10.1016/j.wneu.2017.09.137 ◽

2018 ◽

Vol 109 ◽

pp. e194-e202 ◽

Cited By ~ 8

Author(s):

Gun Woo Lee ◽

Myun-Whan Ahn

Keyword(s):

Comparative Study ◽

Cortical Bone ◽

Pedicle Screw ◽

Interbody Fusion ◽

Posterior Lumbar Interbody Fusion ◽

Lumbar Interbody Fusion ◽

Post Hoc Analysis ◽

Single Level ◽

Cortical Screw ◽

Post Hoc

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Unilateral versus bilateral pedicle screw instrumentation for single-level minimally invasive transforaminal lumbar interbody fusion

Journal of Clinical Neuroscience ◽

10.1016/j.jocn.2013.11.055 ◽

2014 ◽

Vol 21 (9) ◽

pp. 1612-1616 ◽

Cited By ~ 16

Author(s):

Xiaolong Shen ◽

Hailong Zhang ◽

Xin Gu ◽

Guangfei Gu ◽

Xu Zhou ◽

...

Keyword(s):

Minimally Invasive ◽

Pedicle Screw ◽

Interbody Fusion ◽

Transforaminal Lumbar Interbody Fusion ◽

Lumbar Interbody Fusion ◽

Pedicle Screw Instrumentation ◽

Single Level ◽

Bilateral Pedicle Screw

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Computed tomography Hounsfield unit–based prediction of pedicle screw loosening after surgery for degenerative lumbar spine disease

Journal of Neurosurgery Spine ◽

10.3171/2019.11.spine19868 ◽

2020 ◽

Vol 32 (5) ◽

pp. 716-721

Author(s):

Da Zou ◽

Aikeremujiang Muheremu ◽

Zhuoran Sun ◽

Woquan Zhong ◽

Shuai Jiang ◽

...

Keyword(s):

Logistic Regression ◽

Regression Analysis ◽

Pedicle Screw ◽

Screw Fixation ◽

Hounsfield Unit ◽

Pedicle Screw Fixation ◽

Screw Loosening ◽

Pedicle Screw Loosening ◽

Spine Disease ◽

Lumbar Pedicle

OBJECTIVEThe authors investigated the relation between Hounsfield unit (HU) values measured on CT and the risk of pedicle screw loosening in patients who underwent lumbar pedicle screw fixation for degenerative lumbar spine disease.METHODSPatients who were treated with lumbar pedicle screw fixation between July 2011 and December 2015 at the authors’ department were reviewed. Age, sex, BMI, smoking and diabetes histories, range of fixation, and fusion method were recorded as the basic patient information. The HU values for lumbar bone mineral density (BMD) for the L1, L2, L3, and L4 vertebra were measured on CT scans. Logistic regression analysis was used to identify the independent influencing factors of pedicle screw loosening.RESULTSA total of 503 patients were included in the final analysis. The pedicle screw loosening rate at the 12-month follow-up was 30.0% (151 of 503 patients). There were no significant differences in sex, BMI, or histories of smoking and diabetes between the patients with (loosening group) and those without (nonloosening group) screw loosening (p > 0.05). The mean HU value of L1–4 was lower in the loosening group than the nonloosening group (106.3 ± 33.9 vs 132.6 ± 42.9, p < 0.001). In logistic regression analysis, being male (OR 2.065; 95% CI 1.242–3.433), HU value (OR 0.977; 95% CI 0.970–0.985), length of fixation (OR 3.616; 95% CI 2.617–4.996), and fixation to S1 (OR 1.699; 95% CI 1.039–2.777) were the independent influencing factors for screw loosening.CONCLUSIONSHU value measured on CT was an independent predictor for pedicle screw loosening, and lower HU value was significantly correlated with higher risk of screw loosening.

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Obesity may be associated with adjacent-segment degeneration after single-level transforaminal lumbar interbody fusion in spinopelvic-mismatched patients with a minimum 2-year follow-up

Journal of Neurosurgery Spine ◽

10.3171/2020.6.spine20159 ◽

2021 ◽

Vol 34 (1) ◽

pp. 83-88

Author(s):

Ping-Guo Duan ◽

Praveen V. Mummaneni ◽

Minghao Wang ◽

Andrew K. Chan ◽

Bo Li ◽

...

Keyword(s):

Interbody Fusion ◽

Transforaminal Lumbar Interbody Fusion ◽

Adjacent Segment Degeneration ◽

Adjacent Segment ◽

Lumbar Interbody Fusion ◽

Inclusion Criteria ◽

Single Level ◽

Degenerative Lumbar Spondylolisthesis ◽

Surgery Rates

OBJECTIVEIn this study, the authors’ aim was to investigate whether obesity affects surgery rates for adjacent-segment degeneration (ASD) after transforaminal lumbar interbody fusion (TLIF) for spondylolisthesis.METHODSPatients who underwent single-level TLIF for spondylolisthesis at the University of California, San Francisco, from 2006 to 2016 were retrospectively analyzed. Inclusion criteria were a minimum 2-year follow-up, single-level TLIF, and degenerative lumbar spondylolisthesis. Exclusion criteria were trauma, tumor, infection, multilevel fusions, non-TLIF fusions, or less than a 2-year follow-up. Patient demographic data were collected, and an analysis of spinopelvic parameters was performed. The patients were divided into two groups: mismatched, or pelvic incidence (PI) minus lumbar lordosis (LL) ≥ 10°; and balanced, or PI-LL < 10°. Within the two groups, the patients were further classified by BMI (< 30 and ≥ 30 kg/m2). Patients were then evaluated for surgery for ASD, matched by BMI and PI-LL parameters.RESULTSA total of 190 patients met inclusion criteria (72 males and 118 females, mean age 59.57 ± 12.39 years). The average follow-up was 40.21 ± 20.42 months (range 24–135 months). In total, 24 patients (12.63% of 190) underwent surgery for ASD. Within the entire cohort, 82 patients were in the mismatched group, and 108 patients were in the balanced group. Within the mismatched group, adjacent-segment surgeries occurred at the following rates: BMI < 30 kg/m2, 2.1% (1/48); and BMI ≥ 30 kg/m2, 17.6% (6/34). Significant differences were seen between patients with BMI ≥ 30 and BMI < 30 (p = 0.018). A receiver operating characteristic curve for BMI as a predictor for ASD was established, with an AUC of 0.69 (95% CI 0.49–0.90). The optimal BMI cutoff value determined by the Youden index is 29.95 (sensitivity 0.857; specificity 0.627). However, in the balanced PI-LL group (108/190 patients), there was no difference in surgery rates for ASD among the patients with different BMIs (p > 0.05).CONCLUSIONSIn patients who have a PI-LL mismatch, obesity may be associated with an increased risk of surgery for ASD after TLIF, but in obese patients without PI-LL mismatch, this association was not observed.

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