Publications by authors named "Yiguo Yan"

11 Publications

  • Page 1 of 1

Percutaneous spinal endoscopy with unilateral interlaminar approach to perform bilateral decompression for central lumbar spinal stenosis: radiographic and clinical assessment.

BMC Musculoskelet Disord 2021 Mar 1;22(1):236. Epub 2021 Mar 1.

Department of Spine Surgery, The First Affiliated Hospital of University of South China, Hengyang, People's Republic of China.

Background: Recently, a percutaneous spinal endoscopy unilateral posterior interlaminar approach to perform bilateral decompression has been proposed for use in treatment of lumbar spinal stenosis, As a development and supplement to traditional surgery, its advantages regarding therapeutic effects and prognosis, such as minor soft tissue damage, little intraoperative blood loss, and a quick return to daily life. However, there are few analyses of this surgery with a follow-up of more than 1 year,we conducted this study in order to quantitatively investigate radiographic and clinical efficacies of this surgery for central lumbar spinal stenosis.

Materials And Methods: Forty-six patients with central lumbar spinal stenosis were enrolled from January 2017 to July 2018. The visual analog scale (VAS) for back pain and leg pain, Oswestry disability index (ODI), modified MacNab criteria were used to evaluate clinical efficiency at preoperative and postoperative time points. The intervertebral height index (IHI), cross-sectional area of the spinal canal (CSAC), calibrated disc signal (CDS) and spinal stability were examined to assess radiographic decompression efficiency via magnetic resonance imaging and X-ray at preoperative and postoperative time points.

Results: The VAS score for lower back pain and leg pain improved from 7.50 ± 0.78 to 1.70 ± 0.66 and from 7.30 ± 0.79 to 1.74 ± 0.68, respectively, and the ODI improved from 72.35 ± 8.15 to 16.15 ± 4.51. In terms of modified MacNab criteria, 91.3% of the patients achieved good or excellent outcomes. Furthermore, significant changes after surgery were observed for the percentage of CSAC, increasing from 125.3 ± 53.9 to 201.4 ± 78 mm; however, no significant differences were observed for the remaining measurement indicators.

Conclusions: The clinical and radiographic efficacies of this surgery for central lumbar spinal stenosis were good in short-term follow-up, and this surgery did not cause meaningful changes in IHI, CDS, and spine stability in short-term follow-up. The effect of long-term follow-up needs further investigation.
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http://dx.doi.org/10.1186/s12891-021-04100-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7923329PMC
March 2021

Biomechanical Analysis of a Growing Rod with Sliding Pedicle Screw System for Early-Onset Scoliosis.

J Healthc Eng 2019 12;2019:9535070. Epub 2019 Jun 12.

Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

Early-onset scoliosis (EOS) remains a challenging condition for which current nonfusion surgeries require iterative lengthening surgeries. A growing rod with sliding pedicle screw system (GRSPSS) was developed to treat spinal deformities without repeated operative lengthening. This study was performed to evaluate whether GRSPSS had similar stability as a conventional pedicle screw system to maintain deformity correction. A serial-linkage robotic manipulator with a six-axis load cell positioned on the end-effector was utilized to evaluate the mechanical stability of the GRSPSS versus conventional fixed scoliosis instrumentation. Ten skeletally mature thoracic female Katahdin sheep spines (T4-L1) were subjected to 2.5 Nm of flexion-extension (FE), lateral bending (LB), and axial rotation (AR) in 2° increments for each state. The overall range of motion (ROM), apical segment ROM, and stiffness were calculated and reported. A two-tailed paired -test was used to detect significant differences ( < 0.05) between the fixed group and GRSPSS fixation. There were no significant differences in overall range of motion (ROM), apical segment ROM, or stiffness for FE or LB between the GRSPSS group and fixed group. In AR, the GRSPSS group showed increased ROM compared to the fixed group for the overall spine (36.0° versus 19.2°, < 0.01) and for the instrumented T8-T10 segments (7.0° versus 2.9°, =0.02). Similarly, the fixed rod elastic zone (EZ) stiffness was significantly greater than the GRSPSS EZ stiffness (0.29 N/m versus 0.17 N/m, < 0.001). The space around the rod allows for the increased AR observed with the GRSPSS fusion technique and is necessary for axial growth. The GRSPSS fusion model shows equivalent flexion and LB stability to current fusion models and represents a stable fusion technique and may allow for longitudinal growth during childhood.
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http://dx.doi.org/10.1155/2019/9535070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6594281PMC
September 2020

Influence of follower load application on moment-rotation parameters and intradiscal pressure in the cervical spine.

J Biomech 2018 07 15;76:167-172. Epub 2018 Jun 15.

Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States.

The objective of this study was to implement a follower load (FL) device within a robotic (universal force-moment sensor) testing system and utilize the system to explore the effect of FL on multi-segment cervical spine moment-rotation parameters and intradiscal pressure (IDP) at C45 and C56. Twelve fresh-frozen human cervical specimens (C3-C7) were biomechanically tested in a robotic testing system to a pure moment target of 2.0 Nm for flexion and extension (FE) with no compression and with 100 N of FL. Application of FL was accomplished by loading the specimens with bilateral cables passing through cable guides inserted into the vertebral bodies and attached to load controlled linear actuators. FL significantly increased neutral zone (NZ) stiffness and NZ width but resulted in no change in the range of motion (ROM) or elastic zone stiffness. C45 and C56 IDP measured in the neutral position were significantly increased with application of FL. The change in IDP with increasing flexion rotation was not significantly affected by the application of FL, whereas the change in IDP with increasing extension rotation was significantly reduced by the application of FL. Application of FL did not appear to affect the specimen's quantity of motion (ROM) but did affect the quality (the shape of the curve). Regarding IDP, the effects of adding FL compression approximates the effect of the patient going from supine to a seated position (FL compression increased the IDP in the neutral position). The change in IDP with increasing flexion rotation was not affected by the application of FL, but the change in IDP with increasing extension rotation was, however, significantly reduced by the application of FL.
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http://dx.doi.org/10.1016/j.jbiomech.2018.05.031DOI Listing
July 2018

Adaptation of a clinical fixation device for biomechanical testing of the lumbar spine.

J Biomech 2018 03 5;69:164-168. Epub 2018 Jan 5.

Ferguson Laboratory for Spine Research, Department of Orthopedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA.

In-vitro biomechanical testing is widely performed for characterizing the load-displacement characteristics of intact, injured, degenerated, and surgically repaired osteoligamentous spine specimens. Traditional specimen fixture devices offer an unspecified rigidity of fixation, while varying in the associated amounts and reversibility of damage to and "coverage" of a specimen - factors that can limit surgical access to structures of interest during testing as well as preclude the possibility of testing certain segments of a specimen. Therefore, the objective of this study was to develop a specimen fixture system for spine biomechanical testing that uses components of clinically available spinal fixation hardware and determine whether the new system provides sufficient rigidity for spine biomechanical testing. Custom testing blocks were mounted into a robotic testing system and the angular deflection of the upper fixture was measured indirectly using linear variable differential transformers. The fixture system had an overall stiffness 37.0, 16.7 and 13.3 times greater than a typical human functional spine unit for the flexion/extension, axial rotation and lateral bending directions respectively - sufficient rigidity for biomechanical testing. Fixture motion when mounted to a lumbar spine specimen revealed average motion of 0.6, 0.6, and 1.5° in each direction. This specimen fixture method causes only minimal damage to a specimen, permits testing of all levels of a specimen, and provides for surgical access during testing.
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http://dx.doi.org/10.1016/j.jbiomech.2017.12.029DOI Listing
March 2018

Tumor necrosis factor-α: a key contributor to intervertebral disc degeneration.

Acta Biochim Biophys Sin (Shanghai) 2017 Jan 17;49(1):1-13. Epub 2016 Nov 17.

Department of Spine Surgery, The First Affiliated Hospital, University of South China, Hengyang 421001, China

Intervertebral disc (IVD) degeneration (IDD) is the most common cause leading to low back pain (LBP), which is a highly prevalent, costly, and crippling condition worldwide. Current treatments for IDD are limited to treat the symptoms and do not target the pathophysiology. Tumor necrosis factor-α (TNF-α) is one of the most potent pro-inflammatory cytokines and signals through its receptors TNFR1 and TNFR2. TNF-α is highly expressed in degenerative IVD tissues, and it is deeply involved in multiple pathological processes of disc degeneration, including matrix destruction, inflammatory responses, apoptosis, autophagy, and cell proliferation. Importantly, anti-TNF-α therapy has shown promise for mitigating disc degeneration and relieving LBP. In this review, following a brief description of TNF-α signal transduction, we mainly focus on the expression pattern and roles of TNF-α in IDD, and summarize the emerging progress regarding its inhibition as a promising biological therapeutic approach to disc degeneration and associated LBP. A better understanding will help to develop novel TNF-α-centered therapeutic interventions for degenerative disc disease.
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http://dx.doi.org/10.1093/abbs/gmw112DOI Listing
January 2017

Application of Laparoscopic Lumbar Discectomy and Artificial Disc Replacement: At Least Two Years of Follow-Up.

Spine (Phila Pa 1976) 2016 Oct;41 Suppl 19:B38-B43

*Department of Spinal Surgery, the First Affiliated Hospital of University of South China, Hengyang, HuNan Province, China †The Orthopaedic Department of Sun YiXian Hospital of Zhongshan University, Guangzhou, Guangdong Province, China.

Study Design: This prospective observational study included 22 patients who were diagnosed with symptomatic degenerative disc disease treated via artificial disc replacement (ADR) with a laparoscopic technique.

Objective: The current study aimed to assess the safety and efficacy of ADR using a laparoscopic technique for lumbar disc herniation.

Summary Of Background Data: Symptomatic degenerative disc disease is the major cause of low back pain with lumbar segmental instability. ADR has increased in popularity as an alternative treatment for lumbar disc herniation. However, the traditional approach to spinal surgery carries the risk of catastrophic bleeding from injury to major vessels, as well as iatrogenic injury to the viscera and associated structures. Therefore, laparoscopic lumbar discectomy and ADR may represent a useful alternative.

Methods: Twenty-two patients (8 males and 14 females) who were diagnosed with symptomatic degenerative disc disease were included in this study. Seven cases involved the L4/5 level, and 15 cases involved the L5/S1 level. All patients were ineffective after at least 6 months of conservative treatments; all patients were informed of the surgery before the operation and provided consent. Three-dimensional computed tomographic angiography (3D-CTA) of the iliac great blood vessels was completed before the surgery. All surgical procedures were performed under a laparoscope. All patients were followed up.

Results: All surgeries were successfully completed. The average operation time was 120 minutes (range 110-150 min), and the average hemorrhage was 145 mL (range 80-360 mL). All cases underwent X-rays at 3 days, 3 months, 6 months, 1 year, and the final postoperative follow-up. The outcome indicated that there was no mobilization, displacement, or subsidence in all patients with the exception of one case with prosthesis migration. The follow-up time was 43.8 months (range 24-64 months). The mean visual analog scale (VAS) and Oswestry scores were decreased postoperatively. The mean improvement rate of the VAS score was 73.5%.

Conclusion: Lumbar ADR using a laparoscope represents a novel, minimally invasive treatment for symptomatic degenerative disc disease and severe lumbar discogenic pain.
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http://dx.doi.org/10.1097/BRS.0000000000001820DOI Listing
October 2016

[MicroRNAs: a type of novel regulative factor for intervertebral disc degeneration].

Zhejiang Da Xue Xue Bao Yi Xue Ban 2016 Mar;45(2):170-8

Institute of Cardiovascular Disease, Key Laboratory for Arteriosclerology of Hunan Province, University of South China, Hengyang 421001, China.

Intervertebral disc degeneration (IDD) is one of major causes for intervertebral disc degenerative diseases, and patients with IDD usually suffer from serious low back pain. The current treatments for patients with IDD only relieve the clinical symptom rather than restore biological balance of IDD, leading to inadequate and unsatisfactory results. MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded RNA molecules, which regulate the gene expression at the post-transcription levels. Research evidences support the involvement of miRNAs in many biological processes, such as lipid metabolism, apoptosis, differentiation and organ development. Accumulating evidences indicate that the expressions of miRNAs change significantly in degenerative tissues. In addition, dysregulated miRNAs contribute to multiple pathological process of IDD, including proliferation and apoptosis of nucleus pulposus and extracellular matrix components, inflammatory response and cartilage endplates degeneration. In this review article, we summarize the expression profiles and roles of miRNAs in IDD, which may provide a novel strategy of biological therapy for the disease.
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March 2016

Influence of varying compressive loading methods on physiologic motion patterns in the cervical spine.

J Biomech 2016 Jan 27;49(2):167-72. Epub 2015 Nov 27.

Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.

The human cervical spine supports substantial compressive load in-vivo arising from muscle forces and the weight of the head. However, the traditional in-vitro testing methods rarely include compressive loads, especially in investigations of multi-segment cervical spine constructs. Various methods of modeling physiologic loading have been reported in the literature including axial forces produced with inclined loading plates, eccentric axial force application, follower load, as well as attempts to individually apply/model muscle forces in-vitro. The importance of proper compressive loading to recreate the segmental motion patterns exhibited in-vivo has been highlighted in previous studies. However, appropriate methods of representing the weight of head and muscle loading are currently unknown. Therefore, a systematic comparison of standard pure moment with no compressive loading versus published and novel compressive loading techniques (follower load - FL, axial load - AL, and combined load - CL) was performed. The present study is unique in that a direct comparison to continuous cervical kinematics over the entire extension to flexion motion path was possible through an ongoing intra-institutional collaboration. The pure moment testing protocol without compression or with the application of follower load was not able to replicate the typical in-vivo segmental motion patterns throughout the entire motion path. Axial load or a combination of axial and follower load was necessary to mimic the in-vivo segmental contributions at the extremes of the extension-flexion motion path. It is hypothesized that dynamically altering the compressive loading throughout the motion path is necessary to mimic the segmental contribution patterns exhibited in-vivo.
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http://dx.doi.org/10.1016/j.jbiomech.2015.11.045DOI Listing
January 2016

Genetic susceptibility to total hip arthroplasty failure: a case-control study on the influence of MMP 1 gene polymorphism.

Diagn Pathol 2014 Sep 26;9:177. Epub 2014 Sep 26.

Background: Genetic factors plays an important role in early failure of total hip arthroplasty (THA) etiology and MMP-1 gene polymorphism rs5854 may be involved. The present study was conducted to reveal the possible association between MMP-1 rs5854 C/T polymorphism and the risk of early failure of THA (aseptic loosening).

Methods: The rs5854 single nucleotide polymorphism (SNP) in MMP-1 gene was genotyped in 63 subjects who were diagnosed as aseptic loosening after total hip arthroplasty within 10 years and in 81 age and gender matched controls.

Results: The genotype frequencies of the MMP-1 rs5854 C/T polymorphism were 57.1% (CC), 28.6% (CT), and 14.3% (TT) in patients with failure of THA, and 79.0% (CC), 17.3% (CT), and 3.7% (TT) in the controls (P=0.0099). Rs5854 polymorphism was found to be significantly associated with increased risk of aseptic loosening.

Conclusion: The results showed the rs5854 SNP was associated with increased risk of the early aseptic loosening susceptibility.

Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/13000_2014_177.
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http://dx.doi.org/10.1186/s13000-014-0177-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4180955PMC
September 2014

Clinical effect evaluation of percutaneous vertebroplasty combined with the spinal external fixator for the treatment of osteoporotic compressive fractures with posterior vertebral defect.

Eur Spine J 2014 Dec 29;23(12):2711-7. Epub 2014 Aug 29.

Spinal Department, First Affiliated Hospital of University of South China, 69 Chuanshan Road, Hengyang, 421001, Hunan, China.

Purpose: The purpose of this study is to report a new technique and assess clinical outcome of compressive fractures with posterior vertebral defect treated by percutaneous vertebroplasty combined with the spinal external fixator.

Method: 80 patients (32 males and 48 females), ranging from 62 to 88 years old with the mean age of 71.5 years, underwent surgery for the compressive fractures with posterior vertebral defect by percutaneous vertebroplasty combined with the spinal external fixator. All patients were diagnosed to have fresh compressive fractures with osteoporosis and posterior vertebral defect shown on roentgenograms, computed tomography scans or magnetic resonance imaging preoperatively. They underwent spinal external fixation firstly to be fixed and restored, then to be carried out percutaneous vertebroplasty. The mean follow-up was 24 months (16-42 months). Spinal canal encroachment, spinal cobb angle and vertebral body height loss were measured to assess clinical outcome before and after surgery, at the final follow-up. The Visual Analogue Scale and Oswestry Disability Index were used for pain and functional assessment. In all cases, preoperative and postoperative radiographs and magnetic resonance imaging were obtained.

Results: The average time of surgery was 88 min (75-115 min). The mean blood loss was 10 ml (6-12 ml) during surgery. The anterior height loss of vertebral body decreased significantly from 79.3 ± 11% before surgery to 8.0 ± 5.2% after surgery, and 7.6 ± 6.0% at the final follow-up. The spinal canal encroachment significantly reduced from 19.9 ± 2.6 % preoperatively to 4.0 ± 0.7% postoperatively, 4.1 ± 0.7% at the final follow-up. The Cobb angle was corrected from 25.8 ± 7.9° primarily to 8.2 ± 4.1° postoperatively, 7.8 ± 3.1° at the final follow-up. There were significant differences (p < 0.05) among them before and after the surgery. Postoperative VAS and Oswestry scores were both significantly different from the preoperative and follow-up (p < 0.05).

Conclusion: The preliminary results are encouraging, showing that the spinal external fixator combined with percutaneous vertebroplasty was a safe and effective method to treat the osteoporotic compressive fractures with posterior vertebral defect.
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http://dx.doi.org/10.1007/s00586-014-3346-3DOI Listing
December 2014

External spinal skeletal fixation combination with percutaneous injury vertebra bone grafting in the treatment of thoracolumbar fractures.

Spine (Phila Pa 1976) 2011 Apr;36(9):E606-11

Spinal Department, First Affiliated Hospital of University of South China, Hengyang city, Hunan, China.

Study Design: A technical report of thoracolumbar fractures managed by percutaneous external pedicular fixation and intracorporeal bone grafting.

Objective: To develop a new technique by combining simplified percutaneous external pedicular fixator with intracorporeal bone grafting to treat thoracolumbar fractures and assess its technical safety and clinical efficacy.

Summary Of Background Data: For surgical treatment of thoracolumbar fractures, the classical techniques are beneficial in decompression, restoration, fixation, and graft fusion, but they are also hugely invasive procedures. The earlier external spinal fixation procedures are good at indirect restoration, decompression, and elastic fixation of spinal fracture. However, they are limited by remains of a large external frame and inability of vertebral reconstruct. Therefore, the minimally invasive techniques combining simplified percutaneous external pedicular fixation and intracorporeal bone grafting might be a useful alternative.

Methods: There were 50 consecutive patients who had thoracolumbar fractures with or without associated incomplete neurologic deficit. They underwent percutaneous external pedicle fixation and intracorporeal bone grafting surgery within 7 days of admission, had their implants removed after 3 months, and were prospectively followed for at least 12 months. American Spine Injury Association grading, spinal canal encroachment, spinal Cobb angle, and vertebral body height were calculated before and after surgery to assess clinical outcome.

Results: A minimum of 12-month follow-up was achieved in 50 patients. The average operative time was 90 minutes (range, 50-160 minutes). The mean bone graft volume was 4.8 cm (range, 3.2-10.6 cm). The intraoperative mean blood loss was 100 mL (range, 50-180 mL). Forty-two patients all had at least one American Spine Injury Association grade neurologic improvement on final follow-up observation; there were no surgery-related complications. The mean anterior height of vertebral body was 53.2% (range 25%-78%) before surgery, 93.6% (range 78%-104%) after surgery, and 94% (range 79%-103%) at final follow-up. The preoperative Cobb angle of the primary curve averaged 30.7° (range 8°-67°), and corrected to 4.5° (range 0°-12.0°) immediately after surgery, There were statistically significant (P < 0.01) among them before and after operation. There was no instrumentation failure or measurable loss of sagittal curve and vertebral height correction in any cases.

Conclusion: The new technique by combination of percutaneous external transpedicular fixation and transpedicular bone grafting is a feasible, safe, useful, efficient, and minimally invasive method to treat thoracolumbar fractures. It is a reasonable alternative method to other minimally invasive techniques of surgical management of the thoracolumbar fractures.
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http://dx.doi.org/10.1097/BRS.0b013e3181f92dacDOI Listing
April 2011