Comparison of Clinical and Radiographic Outcomes Between Transforaminal Endoscopic Lumbar Discectomy and Microdiscectomy: A Follow-up Exceeding 5 Years.

OBJECTIVE: To compare the long-term clinical and radiographic outcomes of transforaminal endoscopic lumbar discectomy (TELD) versus microdiscectomy (MD). METHODS: The data of 154 patients with lumbar disc herniation (LDH) who underwent TELD (n = 89) or MD (n = 65) were retrospectively analyzed. The patients' clinical outcomes were evaluated using visual analogue scales for leg and low back pain, the Japanese Orthopaedic Association (JOA) score, and the Oswestry Disability Index (ODI). The evolution of radiographic manifestations was observed during follow-up. Potential risk factors for a poor clinical outcome were investigated. RESULTS: During a mean follow-up of 5.5 years (range, 5-7 years), the recurrence rate was 4.49% in the TELD group and 1.54% in the MD group. All scores significantly improved from preoperatively to postoperatively in both groups (p < 0.01). The improvement in the ODI and JOA scores was significantly greater in the TELD than MD group (p < 0.05). Forty-seven patients (52.8%) in the TELD group and 32 (49.2%) in the MD group had Modic changes before surgery, most of which showed no changes at the last follow-up. The degeneration grades of 292 discs (71.0%) were unchanged at the last follow-up, while 86 (20.9%) showed improvement, mostly at the upper adjacent segment. No significant difference was observed in the intervertebral height index or paraspinal muscle-disc ratio. CONCLUSION: Both TELD and MD provide generally satisfactory long-term clinical outcomes for patients with LDH. TELD can be used as a reliable alternative to MD with less surgical trauma. Modic type II changes, decreased preoperative intervertebral height, and a high body mass index are predictors of a poor prognosis.

Facet joint tropism, pelvic incidence and intervertebral height index: associations with facet joint osteoarthritis in lumbar spinal stenosis.

BACKGROUND CONTEXT: Facet joint osteoarthritis (FJOA) is associated with lumbar disc degeneration and has a significant role in the development of lumbar spinal stenosis (LSS). The relationship between various radiographic parameters and the grade of FJOA is not well understood. PURPOSE: To explore radiographical parameters associated with FJOA in LSS without lumbar dynamic instability. STUDY DESIGN: Retrospective study analysis. PATIENT SAMPLE: A total of 122 patients diagnosed with LSS who visited our hospital between January 2015 and July 2022. OUTCOME MEASURES: We evaluated radiographic parameters of patients at L4-5 including lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), grades of FJOA, facet joint orientation (FO), facet joint tropism (FT), intervertebral height index (IHI) and the relative cross-sectional area (RCSA) of paraspinal muscles. METHODS: Patients diagnosed with LSS between January 2015 and July 2022 were enrolled. Demographic characteristics and radiographic parameters were collected. Spinopelvic parameters were measured through the preoperative lateral image of the whole spine, including LL, PI, pelvic tilt, and sacral slope. Lumbar computed tomography scan and magnetic resonance imaging were collected to measure the FO, FT, IHI, and the RCSA of paraspinal muscles respectively. Patients were divided into three groups according to the severity of FJOA graded by the Weishaupt classification: grade 0 and grade 1 were group A, grade 2 were group B, and grade 3 were group C. All variables were compared among the three groups, while the relationship between parameters and grades of FJOA were also analyzed. RESULTS: A total of 122 patients were included. PI was significantly greater in group C compared to group A (p = 0.025) and group B (p=0.022). FT was significantly greater in group C compared to group A (p<.001) and group B (p<.001). The RCSA of multifidus in group A were significantly greater than that in group B (p=0.02) and C (p=0.002). Additionally, FO in group C were significantly lower than group A (p<.001) and group B (p=0.028). The IHI in group C was significantly lower than group A (p=0.017). The correlation analysis indicated that grades of FJOA was positively related to Age, BMI (body mass index), PI, LL and FT, while negatively related to IHI, FO, RCSA of multifidus and RCSA of psoas major. Furthermore, the logistics regression showed that FT, PI, and IHI were important influence factors for FJOA. CONCLUSIONS: The current study confirmed that FT, PI and IHI were significantly associated with grades of FJOA at L4-5. Additionally, longitudinal studies are needed to understand the causal relationship between these parameters and FJOA.

Factors influencing cage subsidence in anterior cervical corpectomy and discectomy: a systematic review.

PURPOSE: Various factors have been examined in relation to cage subsidence risk, including cage material, cage geometry, bone mineral density, device type, surgical level, bone graft, and patient age. The present study aims to compare and synthesize the literature of both clinical and biomechanical studies to evaluate and present the factors associated with cage subsidence. METHODS: A comprehensive search of the literature from January 2003 to December 2021 was conducted using the PubMed and ScienceDirect databases by following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Following the screening for inclusion and exclusion criteria, a total of 49 clinical studies were included. Correlations between clinical and biomechanical studies are also discussed. RESULTS: Patients treated with the cage and plate combination had a lower subsidence rate than patients with the stand-alone cage. Overall, Polyetheretherketone material was shown to have a lower subsidence rate than titanium and other materials. The subsidence rate was also higher when the surgery was performed at levels C5-C7 than at levels C2-C5. No significant correlation was found between age and cage subsidence clinically. CONCLUSIONS: Cage subsidence increases the stress on the anterior fixation system and may cause biomechanical instability. Severe cage subsidence decreases the Cobb angle and intervertebral height, which may cause destabilization of the implant system, such as screw/plate loosening or breakage of the screw/plate. Various factors have been shown to influence the risk of cage subsidence. Examining clinical research alongside biomechanical studies offers a more comprehensive understanding of the subject.

Biomechanical effects of interbody cage height on adjacent segments in patients with lumbar degeneration: a 3D finite element study.

OBJECTIVE: To investigate the biomechanical effects of interbody cage height on adjacent segments in patients with lumbar degeneration undergoing transforaminal lumbar interbody fusion (TLIF) surgery, so as to provide references for selection of interbody cage. METHODS: The finite element model of normal lower lumbar spine (L3-S1) was built and validated, then constructed three different degenerative segments in L3-L4, and the cages with different height (8, 10, 12, 14 mm) were implanted into L4-L5 disc. All the twelve models were loaded with pure moment of 7.5 N m to produce flexion, extension, lateral bending and axial rotation motions on lumbar spine, and the effects of cage height on range of motion (RoM) and intervertebral pressure in lumbar spine were investigated. RESULTS: The RoM of adjacent segments and the maximum stress of intervertebral discs increased with the increase in cage height, but this trend was not obvious in mild and moderate degeneration groups. After implantation of four different height cages (8, 10, 12, 14 mm), the RoM of L3/L4 segment reached the maximum during extension. The RoM of mild degeneration group was 2.07°, 2.45°, 2.48°, 2.54°, that of moderate degeneration group was 1.79°, 1.97°, 2.05°, 2.05°, and that of severe degeneration group was 1.43°, 1.66°, 1.74°, 1.74°. The stress of L3-L4 intervertebral disc reached the maximum during flexion. The maximum stress of L3-L4 intervertebral disc was 20.16 MPa, 20.28 MPa, 20.31 MPa and 20.33 MPa in the mild group, 20.58 MPa, 20.66 MPa, 20.71 MPa and 20.75 MPa in the moderate group, and 21.27 MPa, 21.40 MPa, 21.50 MPa and 21.60 MPa in the severe group. CONCLUSION: For patients with mild-to-moderate lumbar degenerative disease who need to undergo TLIF surgery, it is recommended that the height of fusion cage should not exceed the original intervertebral space height by 2 mm, while for patients with severe degeneration, a fusion cage close to the original intervertebral height should be selected as far as possible, and the intervertebral space should not be overstretched.

Intervertebral disc injury is the mainspring for the postoperative increase in Cobb Angle after thoracolumbar burst fracture.

STUDY DESIGN: A single-institution retrospective study of a cohort of patients who underwent internal fixation spine surgery for thoracolumbar burst fracture (TLBF). OBJECTIVE: To observe the imaging manifestations of intervertebral disc changes in TLBF, to analyze the relationship between the degree of disc injury and the Cobb angle increase. METHODS: We retrospectively analyzed the data of patients who underwent short-segment pedicle screw instrumentation in the spinal surgery department of a single hospital between January 2014 and December 2017 (n = 90). According to the magnetic resonance imaging characteristics of the superior intervertebral disc tissue of the injured vertebrae before the operation, the intervertebral disc injury was divided into three types, which was used for group allocation: group A, uninjured intervertebral disc group; group B, mild intervertebral disc injury group; and group C, severe intervertebral disc injury group. The main imaging results of the three groups Cobb, IVA, IHI, AHIV, and VAS were compared among groups. RESULTS: Ninety patients were included in the study (n = 38, 32, and 20, in groups A, B, and C, respectively). There was no statistically significant difference in demographics among the three groups (p > .05). 1-year post-surgery, the Cobb angle in group C differed significantly from that in groups A and B (p < .01). There was a significant difference in Cobb angle between groups A and B after internal fixation was removed for 6 months. At 1-year post-surgery, the IHI group C differed significantly from groups A and B (p < .01), while groups A and B were similar (p = .102); however, at 6 months after the internal fixation was removed, the IHI differed significantly between these two groups, also the AHIV between groups A and B was statistically significant (p < .01). The VAS pain score was similar among the three groups. Pearson's test showed that the increase in the Cobb angle was moderately correlated with IVA and IHI, and weakly correlated with AHIV. CONCLUSION: For TLBF with an intervertebral disc injury, the presurgical degree of intervertebral disc injury is the main reason for the post-surgery increase in the Cobb angle. Thus, diagnosis and treatment of this kind of patient require attention to the risk of spinal deformity.

Effects of endplate coverage and intervertebral height change on heterotopic ossification following cervical disc replacement.

BACKGROUND: Heterotopic ossification (HO) is a common complication after cervical disc replacement (CDR). Biomechanical factors including endplate coverage and intervertebral disc height change may be related to HO formation. However, there is a dearth of quantitative analysis for endplate coverage, intervertebral height change and their combined effects on HO. METHODS: Patients who underwent single-level or two-level CDR with Prestige-LP were retrospectively reviewed. Clinical outcomes were evaluated through Japanese Orthopaedic Association (JOA) score, Neck Disability Index (NDI) score, and visual analogue scale (VAS) score. Radiological data, including the prosthesis-endplate depth ratio, intervertebral height change, posterior heterotopic ossification (PHO) and angular parameters, were collected. Logistic regression analysis was used to identify the potential risk factors. Receiver operating characteristic curves were plotted and the cut-off values of each potential factors were calculated. RESULTS: A total of 138 patients with 174 surgical segments were evaluated. Both the prosthesis-endplate depth ratio (P < 0.001) and post-operative disc height change (P < 0.001) were predictive factors for PHO formation. The area under the curve (AUC) of the prosthesis-endplate depth ratio, disc height change and their combined effects represented by the combined parameter (CP) were 0.728, 0.712 and 0.793, respectively. The risk of PHO significantly increased when the prosthesis-endplate depth ratio < 93.77% (P < 0.001, OR = 6.909, 95% CI 3.521-13.557), the intervertebral height change ≥ 1.8 mm (P < 0.001, OR = 5.303, 95% CI 2.592-10.849), or the CP representing the combined effect < 84.88 (P < 0.001, OR = 10.879, 95% CI 5.142-23.019). CONCLUSIONS: Inadequate endplate coverage and excessive change of intervertebral height are both potential risk factors for the PHO after CDR. Endplate coverage less than 93.8% or intervertebral height change more than 1.8 mm would increase the risk of PHO. The combination of these two factors may exacerbate the non-uniform distribution of stress in the bone-implant interface and promote HO development.

Mechanical Changes of the Lumbar Intervertebral Space and Lordotic Angle Caused by Posterior-to-Anterior Traction Using a Spinal Thermal Massage Device in Healthy People.

BACKGROUND: The axial (horizontal) traction approach has been traditionally used for treatment of low back pain-related spinal disorders such as nuclear protrusion, primary posterolateral root pain, and lower thoracic disc herniation; however, it is known to have some technical limitations due to reductions of the spinal curve. Lumbar lordosis plays a pivotal function in maintaining sagittal balance. Recently, vertical traction and combination traction have been attracting attention due to improving therapeutic outcomes, although evidence of their clinical application is rare; therefore, this study was conducted to investigate the mechanical changes of lumbar intervertebral space, lordotic angle, and the central spinal canal area through vertical traction treatment using a spinal massage device in healthy participants. METHODS: In total, 10 healthy subjects with no musculoskeletal disorders and no physical activity restrictions participated. The participants lay on the experimental device (CGM MB-1901) in supine extended posture and vertical traction force was applied in a posterior-to-anterior direction on the L3-4 and L4-5 lumbar sections at level 1 (baseline) and level 9 (traction mode). Magnetic resonance (MR) images were recorded directly under traction mode using the MRI scanner. The height values of the intervertebral space (anterior, center, and posterior parts) and lordosis angle of the L3-4 and L4-5 sections were measured using Image J software and the central spinal canal area (L4-5) was observed through superimposition method using the MR images. All measurement and image analyses were conducted by 2 experienced radiologists under a single-blinded method. RESULTS: The average height values of the intervertebral space under traction mode were significantly increased in both L3-4 and L4-5 sections compared to baseline, particularly in the anterior and central parts but not in the posterior part. Cobb's angle also showed significant increases in both L3-4 and L4-5 sections compared to baseline (p < 0.001). The central spinal canal area showed a slightly expanded feature in traction mode. CONCLUSIONS: In this pilot experiment, posterior-to-anterior vertical traction on L3-4 and L4-5 sections using a spinal massage device caused positive and significant changes based on increases of the intervertebral space height, lumbar lordosis angle, and central spinal canal area compared to the baseline condition. Our results are expected to be useful as underlying data for the clinical application of vertical traction.

Change in the postoperative intervertebral space height and its impact on clinical and radiological outcomes after ACDF surgery using a zero-profile device: a single-Centre retrospective study of 138 cases.

BACKGROUND: The effects of postoperative intervertebral height (IH) changes on the clinical and radiological outcomes after anterior cervical decompression and fusion (ACDF) surgery using a zero-profile device remain unclear. METHODS: We retrospectively reviewed patients who had undergone ACDF using a zero-profile device from March 2012 to February 2016 at our institution. Based on the postoperative IH variation, the patients were divided into group A with postoperative IH 0 to 2 mm, group B with postoperative IH 2 to 4 mm, and group C with postoperative IH greater than 4 mm. Clinical efficacy was evaluated using JOA, VAS, and NDI scores in the groups. Imaging parameters including the IH, cervical lordosis, fusion rate, intervertebral foramen (IVF) diameter and complications such as subsidence, dysphagia, and ASD were also compared across the three groups. RESULTS: The average IH increased significantly from 6.72 mm preoperatively to 10.46 mm 1 week after surgery, and then gradually decreased to 7.48 mm at the final follow-up. The fusion rate was 61.90% in group A, 63.23% in group B, 53.57% in group C at 3 months, 73.81% in group A, 79.41% in group B, 67.86% in group C at 6 months, 90.48% in group A, 95.59% in group B, 92.86% in group C 1 year after surgery, and at the last follow-up, the fusion rate of three groups was all 100%. The IVF diameter was 6.52 ± 1.80 mm in group A, 9.55 ± 2.36 mm in group B, and 9.34 ± 1.62 mm in group C. ASD at the superior and inferior levels affected 11.90 and 16.67% patients in group A, 5.88 and 7.38% in group B, and 14.28 and 10.71% in group C. Regarding the 3 groups, the subsidence rates were 7.14, 4.41, and 14.29%, respectively. CONCLUSIONS: No clear correlation was found between IH changes and clinical efficacy within a year of surgery. However, the IH may affect various complications after ACDF. If postoperative IH changes are maintained at 2 to 4 mm after a year, a satisfactory imaging parameters and relatively low complications may be achieved after ACDF surgery using a zero-profile device.

[Comparison of intervertebral height and lordosis of fusion segment between open- and minimally invasive-transforaminal lumbar interbody fusions].

OBJECTIVE: To analyze the restoration of intervertebral height and lordosis of fusion segment after open-transforaminal lumbar interbody fusion (Open-TLIF) and minimally invasive-TLIF (MIS-TLIF). METHODS: Between January 2013 and February 2016, patients who treated with TLIF due to lumbar degenerative diseases and met the selection criteria were selected as the study objects. Among them, 41 patients were treated with open-TLIF (Open-TLIF group), 34 patients were treated with MIS-TLIF (MIS-TLIF group). There was no significant difference between the two groups ( P>0.05) in gender, age, body mass index, disease type, disease duration, pathological segment, and other general data. The intraoperative bleeding volume, hospital stay, visual analogue scale (VAS) score of waist and leg, and Oswestry disability index (ODI) were recorded before and after operation. The anterior disc height (ADH), posterior disc height (ADH), and segmental lordosis (SL) of fusion segment were measured by X-ray film before and at 6 months after operation. The differences of ADH, PDH, and SL between pre- and post-operation were calculated. RESULTS: The intraoperative bleeding volume and hospital stay in Open-TLIF group were significantly higher than those in MIS-TLIF group ( t=14.619, P=0.000; t=10.021, P=0.000). All incisions healed by first intention without early complications. All patients were followed up 6-24 months (mean, 12.6 months) in Open-TLIF group and 6-24 months (mean, 11.5 months) in MIS-TLIF group. The preoperative VAS scores of waist and leg and ODI of the two groups significantly improved ( P<0.05). There was no significant difference in VAS scores and ODI between the two groups before operation and at 2 weeks and 6 months after operation ( P>0.05). Imaging examination showed the good intervertebral fusion. There was no significant difference in ADH, PDH, and SL between the two groups before operation and at 6 months after operation ( P>0.05). The differences of ADH, PDH, and SL between the two groups were not significant ( P>0.05). The ADH, PDH, and SL after operation significantly increased in the two groups ( P<0.05). CONCLUSION: Open-TLIF and MIS-TLIF show similar effectiveness and radiological change in the treatment of single lumbar degenerative diseases and the improved intervertebral height and lordosis, but MIS-TLIF can significantly reduce hospital stay and intraoperative blood loss.

Application of 3d printed interbody fusion cage for cervical spondylosis of spinal cord type: Half-year follow-up of recovery of cervical curvature and intervertebral height / 中国组织工程研究

BACKGROUND: Recent clinical studies have found that during the implantation of biomaterials, the internal environment of the body will change to a certain extent, and different levels of immunity and stress responses will occur. There are also obvious differences in the immune and stress responses of different biological materials. OBJECTIVE: To investigate the effect of 3D printed interbody fusion cage on patients with cervical spondylosis of spinal cord type and its effect on serum cortisol and norepinephrine levels. METHODS: Sixty-three patients with cervical spondylotic myelopathy who were admitted to the Affiliated Hospital of Chengde Medical University from July 2015 to July 2018 were selected, including 40 males and 23 females, aged 30-78 years old. The patients were randomly divided into a research group (n=31) and a control group (n=32) according to a random number table. All patients received anterior cervical decompression and bone graft fusion and internal fixation. Patients in the research group were implanted with 3D printed intervertebral fusion cage during operation. The patients in the control group were implanted with polyetheretherketone interbody fusion cage and allogeneic bone. The operation and complications of the two groups were compared. Serum cortisol and norepinephrine levels were detected before and 1 and 3 days after operation. Cervical curvature and intervertebral height were measured before surgery, 1 week, and 6 months after surgery. Axial symptoms were counted at 6 months after surgery. The trial was approved by the Ethics Committee of the Affiliated Hospital of Chengde Medical University. RESULTS AND CONCLUSION: (1) Operation time, intraoperative blood loss and hospitalization time were not significantly different between the two groups (P > 0.05). (2) Among 31 cases, there were 1 case of screw loosening and 1 case of implant movement in the research group. Among 32 cases, there were 3 cases of screw loosening, 3 cases of immune rejection, 2 cases of implant movement, and 1 case of implant collapse in the control group. The incidence of complications was lower in the research group than that in the control group (P < 0.05). (3) At 1 and 3 days after operation, the levels of cortisol and norepinephrine were higher in both groups than those before surgery (P < 0.05), but above levels were lower in the research group than in the control group (P < 0.001). (4) The cervical curvature and intervertebral height at 1 week and 6 months after operation in both groups were higher than those before surgery (P < 0.05), and above indexes were higher in the research group than in the control group (P < 0.05). (5) The axial symptom in the research group was lighter than that in the control group at 6 months after operation (P < 0.05). (6) The results show that the application of 3D printed interbody fusion cage to cervical spondylotic myelopathy can reduce complications, promote the recovery of cervical curvature and intervertebral height, and improve the stability of cervical spine, and the body’s stress response and axial symptoms are mild.

Comparison of intervertebral height and lordosis of fusion segment between open- and minimally invasive-transforaminal lumbar interbody fusions / 中国修复重建外科杂志

Objective: To analyze the restoration of intervertebral height and lordosis of fusion segment after open-transforaminal lumbar interbody fusion (Open-TLIF) and minimally invasive-TLIF (MIS-TLIF). Methods: Between January 2013 and February 2016, patients who treated with TLIF due to lumbar degenerative diseases and met the selection criteria were selected as the study objects. Among them, 41 patients were treated with open-TLIF (Open-TLIF group), 34 patients were treated with MIS-TLIF (MIS-TLIF group). There was no significant difference between the two groups ( P>0.05) in gender, age, body mass index, disease type, disease duration, pathological segment, and other general data. The intraoperative bleeding volume, hospital stay, visual analogue scale (VAS) score of waist and leg, and Oswestry disability index (ODI) were recorded before and after operation. The anterior disc height (ADH), posterior disc height (ADH), and segmental lordosis (SL) of fusion segment were measured by X-ray film before and at 6 months after operation. The differences of ADH, PDH, and SL between pre- and post-operation were calculated. Results: The intraoperative bleeding volume and hospital stay in Open-TLIF group were significantly higher than those in MIS-TLIF group ( t=14.619, P=0.000; t=10.021, P=0.000). All incisions healed by first intention without early complications. All patients were followed up 6-24 months (mean, 12.6 months) in Open-TLIF group and 6-24 months (mean, 11.5 months) in MIS-TLIF group. The preoperative VAS scores of waist and leg and ODI of the two groups significantly improved ( P0.05). Imaging examination showed the good intervertebral fusion. There was no significant difference in ADH, PDH, and SL between the two groups before operation and at 6 months after operation ( P>0.05). The differences of ADH, PDH, and SL between the two groups were not significant ( P>0.05). The ADH, PDH, and SL after operation significantly increased in the two groups ( P<0.05). Conclusion: Open-TLIF and MIS-TLIF show similar effectiveness and radiological change in the treatment of single lumbar degenerative diseases and the improved intervertebral height and lordosis, but MIS-TLIF can significantly reduce hospital stay and intraoperative blood loss.

Adjacent Intervertebral Disk Height Decrease Phenomenon After Single-Level Transforaminal Lumbar Interbody Fusion of the Lumbar Spine.

BACKGROUND: The increase of intradiskal pressure on the upper segment resulting from intervertebral distraction after lumbar intervertebral fusion decreases intervertebral height and aggravates degeneration. However, the incidence rate and risk factors of the adjacent intervertebral disk height decrease phenomenon have not been studied. The purpose of this study was to identify the incidence rate and risk factors of the adjacent intervertebral disk height decrease phenomenon after single-level transforaminal lumbar interbody fusion (TLIF) of the lumbar spine. METHODS: A retrospection of 68 patients who underwent L4-5 TLIF. Patient age, sex, and body mass index were collected. Lumbar lordosis, facet sagittalization, Pfirrmann classification, L4-5 distraction height, and L3-4 reduction height were evaluated by radiologic image. The patients were divided into 2 groups based on whether their L3-4 intervertebral height decreased. RESULTS: Forty of 68 patients (58.8%) had L3-4 intervertebral height decrease. The patients' mean age was 62.05 ± 10.90 years in the L3-4 intervertebral height decrease positive (IHDP) group, significantly higher than the 56.14 ± 12.06 years in the L3-4 intervertebral height decrease negative (IHDN) group (P = 0.039). The mean facet sagittalization angle in the IHDP group was 67.5° ± 20.36°, significantly larger than the 55.43° ± 14.97° in the IHDN group (P = 0.010). The preoperative lumbar lordosis was significantly higher in the IHDP group (P = 0.049). No significant effects of other factors on L3-4 height decrease were observed (P > 0.05). CONCLUSIONS: Distraction of the L4-5 intervertebral space by cage insertion leads to a reduced height on the adjacent L3-4 segment in some patients. In addition, the decrease in L3-4 intervertebral height resulting from L4-5 distraction was correlated with age, preoperative lumbar lordosis, and facet joint sagittalization.

Biomechanical effects of interbody cage height on cervical spine / 医用生物力学

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3％.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

Biomechanical effects of interbody cage height on cervical spine / 医用生物力学

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3％.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

Biomechanical effects of interbody cage height on cervical spine / 医用生物力学

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery, so as to provide references for selection of interbody cage. Methods The finite element model of normal cervical spine (C2-7) was built and validated, and the cages with different height (5, 6, 7, 8 mm) were implanted into C5-6 disc (cage5, 6, 7, 8 model). All the models were loaded with pure moment of 1.5 N•m to produce flexion, extension, blending and axial torsion motions on the cervical spine, and the effects of cage height on range of motion (ROM), facet joint stress, intervertebral pressure in cervical spine were investigated. Results The intervertebral angle at the fusion segment increased by 0.68°with per 1 mm-increase of height. The ROM at C5-6 after cage implantation was less than 0.44°. The influence of cage height on ROM in C4-5 was greater than that in C6-7, and the changes of ROM in non-fusion segments were less than 7.3%. The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure. The stresses in the capsular ligament, cage and screw-plate system increased gradually with the increase of cage height, and these stresses in the cage6, 7, 8 models were much higher than those in the cage5 model. Conclusions For patients who need implanting fusion cage, the cage height should be 0-1 mm greater than the original intervertebral space height.

Analysis on the effect of different surgical methods on patients with severe cervical spondylotic myelopathy / 中国综合临床

Objective To compare the causes of poor effects after surgical treatment for severe cervical spondylotic myelopathy,and to analyze the clinical value of posterior surgery in the treatment of severe cervical spondylotic myelopathy.Methods From September 2013 to November 2016,ninety-two patients with severe cervical myelopathy in Shiyan Medical Hospital were selected as the research object,the patients were divided into the observation group and the control group,50 cases in each group,according to the different surgical methods,the control group received anterior cervical discectomy and interbody fusion and internal fixation treatment,the observation group was treated with cervical posterior decompression surgical treatment,the prognosis and the changes of cervical vertebra function in the two groups were recorded.Results There were statistically significant differences between the two groups in terms of operation time,intraoperative blood loss and postoperative hospital stay(t=5.392,7.114,4.552,P<0.05).The intervertebral height at 1 month after surgery in the observation group and the control group were(4.92 ± 1.51)mm and(4.26 ± 1.32)mm,significantly lower than those before the operation((3.72±0.42)mm,(3.78±0.93)mm)(t=10.495,6.114,P<0.05) .At 1 month after operation,the intervertebral height of the observation group was significantly higher than that of the control group(t=4.521,P<0.05).The excellent and good rate of JOA score of the observation group and control group at 1 month after operation were 97.6% and 84.0%,respectively,and the rate of the observation group was significantly higher than that of the control group(χ2=4.797,P<0.05).In the observation group and the control group,there were 1 case of throat pain after operation,and they were relieved after suitable treatment.Conclusion Compared with the anterior approach,the posterior treatment of severe cervical spondylotic myelopathy can reduce the trauma of patients,promote the recovery of intervertebral height and improve the function of the cervical spine,so as to achieve better results.

Biomechanical effects of interbody cage height on cervical spine / 医用生物力学

Objective To investigate the biomechanical effects of interbody cage height on cervical spine during anterior cervical discectomy and fusion (ACDF) surgery,so as to provide references for selection of interbody cage.Metheds The finite element model of normal cervical spine (C2-7) was built and validated,and the cages with different height (5,6,7,8 mm) were implanted into C5-6 disc (cage 5,6,7,8 model).All the models were loaded with pure moment of 1.5 N · m to produce flexion,extension,lateral bending and axial rotation motions on cervical spine,and the effects of cage height on range of motion (ROM),facet joint stress,intervertebral pressure in cervical spine were investigated.Results The intervertebral angle at the fusion segment increased by 0.68° with per 1 mm-increase in height.The ROM in C5-6 after cage implantation was smaller than 0.44°.The influence of cage height on ROM in C4-5 was greater than that in C6-7,and the changes of ROM in non-fusion segments were smaller than 7.3％.The cage height variation had a smaller impact on the facet joint stress and intervertebral pressure.The stresses in the capsular ligament,cage and screw-plate system increased gradually with the increase of cage height,and the stresses in cage 6,7,8 models were much higher than those in cage 5 model.Conclusions For patients who need implanting fusion cage,the cage height should be 0-1 mm greater than the original intervertebral space height.

Long-Term Follow-Up Results of Anterior Cervical Inter-Body Fusion with Stand-Alone Cages.

OBJECTIVE: The purpose of this study was to evaluate long-term follow-up radiologic/clinical outcomes of patients who underwent anterior cervical discectomy and inter-body fusion (ACDF) with stand-alone cages (SAC) in a single academic institution. METHODS: Total 99 patients who underwent ACDF with SAC between February 2004 and December 2012 were evaluated retrospectively. A total of 131 segments were enrolled in this study. Basic demographic information, radiographic [segmental subsidence rate, fusion rate, C2-7 global angle, and segmental angle changes)/clinical outcomes (by Odom's criteria and visual analog score (VAS)] and complications were evaluated to determine the long-term outcomes. RESULTS: The majority were males (55 vs. 44) with average age of 53.2. Mean follow-up period was 62.9 months. The segmental subsidence rate was 53.4% and fusion rate was 73.3%. In the subsidence group, anterior intervertebral height (AIH) had more tendency of subsiding than middle or posterior intervertebral height (p=0.01). The segmental angle led kyphotic change related to the subsidence of the AIH. Adjacent segmental disease was occurred in 18 (18.2%) patients. Total 6 (6%) reoperations were performed at the index level. There was no statistical significance between clinical and radiological outcomes. But, overall long-term clinical outcome by Odom's criteria was unsatisfactory (64.64%). The neck and arm VAS score were increased by over time. CONCLUSION: Long-term outcomes of ACDF with SAC group were acceptable but not satisfactory. For optimal decision making, more additional comparative long-term outcome data is needed between ACDF with SAC and ACDF with plating.

Long-Term Follow-Up Results of Anterior Cervical Inter-Body Fusion with Stand-Alone Cages

OBJECTIVE: The purpose of this study was to evaluate long-term follow-up radiologic/clinical outcomes of patients who underwent anterior cervical discectomy and inter-body fusion (ACDF) with stand-alone cages (SAC) in a single academic institution. METHODS: Total 99 patients who underwent ACDF with SAC between February 2004 and December 2012 were evaluated retrospectively. A total of 131 segments were enrolled in this study. Basic demographic information, radiographic [segmental subsidence rate, fusion rate, C2-7 global angle, and segmental angle changes)/clinical outcomes (by Odom's criteria and visual analog score (VAS)] and complications were evaluated to determine the long-term outcomes. RESULTS: The majority were males (55 vs. 44) with average age of 53.2. Mean follow-up period was 62.9 months. The segmental subsidence rate was 53.4% and fusion rate was 73.3%. In the subsidence group, anterior intervertebral height (AIH) had more tendency of subsiding than middle or posterior intervertebral height (p=0.01). The segmental angle led kyphotic change related to the subsidence of the AIH. Adjacent segmental disease was occurred in 18 (18.2%) patients. Total 6 (6%) reoperations were performed at the index level. There was no statistical significance between clinical and radiological outcomes. But, overall long-term clinical outcome by Odom's criteria was unsatisfactory (64.64%). The neck and arm VAS score were increased by over time. CONCLUSION: Long-term outcomes of ACDF with SAC group were acceptable but not satisfactory. For optimal decision making, more additional comparative long-term outcome data is needed between ACDF with SAC and ACDF with plating.

The Relationship between Increased Intervertebral Disc Height and Development of Postoperative Axial Neck Pain after Anterior Cervical Fusion.

OBJECTIVE: To evaluate the relationship between postoperative increase in intervertebral disc space height (IVH) and posterior axial neck in cases of degenerative cervical disease treated with anterior cervical discectomy and fusion (ACDF). METHODS: A total of 155 patients who underwent ACDF with more than 1 year follow up were included. Radiologically, IVH and interfacet distance (IFD) of the operated segment were measured preoperatively and postoperatively. We clinically evaluated neck and arm pains according to visual analogue scale (VAS) scores and assessed neck disability index (NDI) scores preoperatively, postoperatively, at 3 months, 6 months, and 1 year postoperatively. The relationship between radiological parameters, and clinical scores were analyzed using a regression analysis. RESULTS: The mean increase in IVH was 2.62 mm, and the mean increase in IFD was 0.67 mm. The VAS scores for neck pain preoperatively, postoperatively, and at 3 months, 6 months, 1 year postoperatively were 4.46, 2.11, 2.07, 1.95, and 1.29; those for arm pain were 5.89, 3.24, 3.20, 3.03, and 2.18. The NDI scores were improved from 18.52 to 7.47. No significant relationship was observed between the radiological evaluation results regarding the increase in intervertebral height or interfacet distance and clinical changes in VAS or NDI scores. CONCLUSION: The increase in intervertebral space or interfacet distance by the insertion of a large graft material while performing ACDF for the treatment of degenerative cervical disease was not related with the change in VAS scores for neck and arm pains and NDI scores postoperatively and during the follow-up period.