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Biomechanical analysis of a newly developed shape memory alloy hook in a transforaminal lumbar interbody fusion (TLIF) in vitro model.

Wang X, Xu J, Zhu Y, Li J, Zhou S, Tian S, Xiang Y, Liu X, Zheng Y, Pan T - PLoS ONE (2014)

Bottom Line: The UPS significantly reduced the ROM in extension/flexion and lateral bending; the BSMAH significantly reduced the ROM in extension/flexion, lateral bending, and axial rotation; and the USMAH significantly reduced the ROM in flexion and left lateral bending compared with the intact spine (p<0.05).The USMAH slightly reduced the ROM in extension, right lateral bending and axial rotation (p>0.05).Stability provided by the USMAH compared with the UPS was not significantly different.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, PR China.

ABSTRACT

Objective: The objective of this biomechanical study was to evaluate the stability provided by a newly developed shape memory alloy hook (SMAH) in a cadaveric transforaminal lumbar interbody fusion (TLIF) model.

Methods: Six human cadaveric spines (L1-S2) were tested in an in vitro flexibility experiment by applying pure moments of ±8 Nm in flexion/extension, left/right lateral bending, and left/right axial rotation. After intact testing, a TLIF was performed at L4-5. Each specimen was tested for the following constructs: unilateral SMAH (USMAH); bilateral SMAH (BSMAH); unilateral pedicle screws and rods (UPS); and bilateral pedicle screws and rods (BPS). The L3-L4, L4-L5, and L5-S1 range of motion (ROM) were recorded by a Motion Analysis System.

Results: Compared to the other constructs, the BPS provided the most stability. The UPS significantly reduced the ROM in extension/flexion and lateral bending; the BSMAH significantly reduced the ROM in extension/flexion, lateral bending, and axial rotation; and the USMAH significantly reduced the ROM in flexion and left lateral bending compared with the intact spine (p<0.05). The USMAH slightly reduced the ROM in extension, right lateral bending and axial rotation (p>0.05). Stability provided by the USMAH compared with the UPS was not significantly different. ROMs of adjacent segments increased in all fixed constructs (p>0.05).

Conclusions: Bilateral SMAH fixation can achieve immediate stability after L4-5 TLIF in vitro. Further studies are required to determine whether the SMAH can achieve fusion in vivo and alleviate adjacent segment degeneration.

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Related in: MedlinePlus

Range of motion at L3-4.Abbreviations: F, flexion; E, extension; LLB, left lateral bending; RLB, right lateral bending; LR, left rotation; RR, right rotation. USMAH, unilateral shape memory alloy hook; BSMAH, bilateral shape memory alloy hook; UPS, unilateral pedicle screws and rods; BPS, bilateral pedicle screws and rods.
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pone-0114326-g005: Range of motion at L3-4.Abbreviations: F, flexion; E, extension; LLB, left lateral bending; RLB, right lateral bending; LR, left rotation; RR, right rotation. USMAH, unilateral shape memory alloy hook; BSMAH, bilateral shape memory alloy hook; UPS, unilateral pedicle screws and rods; BPS, bilateral pedicle screws and rods.

Mentions: At L3-4 and L5-S1, there was no significant difference in ROM between the constructs compared with the intact spine (p>0.05). Mean ROM of BSMAH and BPS appeared higher compared with the intact spine and USMAH and UPS, but the differences were not significant (Figs. 5, 6).


Biomechanical analysis of a newly developed shape memory alloy hook in a transforaminal lumbar interbody fusion (TLIF) in vitro model.

Wang X, Xu J, Zhu Y, Li J, Zhou S, Tian S, Xiang Y, Liu X, Zheng Y, Pan T - PLoS ONE (2014)

Range of motion at L3-4.Abbreviations: F, flexion; E, extension; LLB, left lateral bending; RLB, right lateral bending; LR, left rotation; RR, right rotation. USMAH, unilateral shape memory alloy hook; BSMAH, bilateral shape memory alloy hook; UPS, unilateral pedicle screws and rods; BPS, bilateral pedicle screws and rods.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4256230&req=5

pone-0114326-g005: Range of motion at L3-4.Abbreviations: F, flexion; E, extension; LLB, left lateral bending; RLB, right lateral bending; LR, left rotation; RR, right rotation. USMAH, unilateral shape memory alloy hook; BSMAH, bilateral shape memory alloy hook; UPS, unilateral pedicle screws and rods; BPS, bilateral pedicle screws and rods.
Mentions: At L3-4 and L5-S1, there was no significant difference in ROM between the constructs compared with the intact spine (p>0.05). Mean ROM of BSMAH and BPS appeared higher compared with the intact spine and USMAH and UPS, but the differences were not significant (Figs. 5, 6).

Bottom Line: The UPS significantly reduced the ROM in extension/flexion and lateral bending; the BSMAH significantly reduced the ROM in extension/flexion, lateral bending, and axial rotation; and the USMAH significantly reduced the ROM in flexion and left lateral bending compared with the intact spine (p<0.05).The USMAH slightly reduced the ROM in extension, right lateral bending and axial rotation (p>0.05).Stability provided by the USMAH compared with the UPS was not significantly different.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, The Sixth Affiliated Hospital of Sun Yat-sen University, Guangzhou, PR China.

ABSTRACT

Objective: The objective of this biomechanical study was to evaluate the stability provided by a newly developed shape memory alloy hook (SMAH) in a cadaveric transforaminal lumbar interbody fusion (TLIF) model.

Methods: Six human cadaveric spines (L1-S2) were tested in an in vitro flexibility experiment by applying pure moments of ±8 Nm in flexion/extension, left/right lateral bending, and left/right axial rotation. After intact testing, a TLIF was performed at L4-5. Each specimen was tested for the following constructs: unilateral SMAH (USMAH); bilateral SMAH (BSMAH); unilateral pedicle screws and rods (UPS); and bilateral pedicle screws and rods (BPS). The L3-L4, L4-L5, and L5-S1 range of motion (ROM) were recorded by a Motion Analysis System.

Results: Compared to the other constructs, the BPS provided the most stability. The UPS significantly reduced the ROM in extension/flexion and lateral bending; the BSMAH significantly reduced the ROM in extension/flexion, lateral bending, and axial rotation; and the USMAH significantly reduced the ROM in flexion and left lateral bending compared with the intact spine (p<0.05). The USMAH slightly reduced the ROM in extension, right lateral bending and axial rotation (p>0.05). Stability provided by the USMAH compared with the UPS was not significantly different. ROMs of adjacent segments increased in all fixed constructs (p>0.05).

Conclusions: Bilateral SMAH fixation can achieve immediate stability after L4-5 TLIF in vitro. Further studies are required to determine whether the SMAH can achieve fusion in vivo and alleviate adjacent segment degeneration.

Show MeSH
Related in: MedlinePlus