Prevalence of Lumbar Segmental Instability in Young Individuals with the Different Types of Lumbar Disc Herniation-Preliminary Report

Spinopelvic malalignment correlates to lumbar instability and lumbar musculature in chronic low back pain-an exploratory study

As PI-LL mismatch is an effective index for spinal surgery and PI-LL less than 10 probably indicates better quality of life, this study aimed to assess spinopelvic parameters, lumbar instability, and lumbar muscle morphology in patients with chronic low back pain (CLBP) with different PI-LL mismatches. This cross-sectional study included 158 CLBP patients. The association between lumbar extensor muscle morphology (measured from magnetic resonance imaging) and spinopelvic parameters (measured from standing lateral radiographs) and lumbar instability (measured from lumbar flexion/extension radiographs) was compared between two groups of patients with different PI-LL mismatch. PI-LL mismatch showed a significant medium association with lumbar spine stability (χ2 = 8.06, p-value = 0.005, OR = 0.26, 95% CI = 0.10 to 0.69). Total cross-sectional area (TCSA) (OR = < 0.001, 95% CI = < 0.001 to < 0.001), functional cross-sectional area (FCSA) (OR = < 0.001, 95% CI = < 0.001 to < 0. 001) of the multifidus, psoas major TCSA (OR = < 0.001, 95% CI = < 0.001 to < 0.001) and its FCSA (OR = < 0.001, 95% CI = < 0.001 to 0.009) showed a strong negative association with PI-LL mismatch. Patients with lower PI-LL mismatch are younger and have less spinopelvic deviation. They have more local spinal compensatory mechanisms such as increased lumbar lordosis. They have better lumbar musculature and less disability but more lumbar instability.

High intensity in interspinous ligaments: a diagnostic sign of lumbar instability and back pain for degenerative lumbar spondylolisthesis

BACKGROUND

To investigate the clinical significance of high intensity signals in interspinous ligaments at the affected segment in degenerative lumbar spondylolisthesis (DLS), as well as to determine the most effective diagnostic modalities for evaluating segmental instability.

METHODS

This study reviewed a consecutive series of patients with L4/5 DLS between July 2023 and December 2023. The enrolled patients were divided into two groups based on the presence or absence of high-intensity signals in interspinous ligaments: the higher group (Group H), and the non-higher group (Group NH). Translational and angular motion was determined using flexion and extension (FE) radiographs or a sitting lumbar lateral radiograph with a supine sagittal MR image (combined, S-MR). The five-repetition sit-to-stand test (5R-STS) was employed to evaluate patients' objective functional impairment (OFI).

RESULTS

Overall, 73 patients were enrolled in this study, and there were 22 (30.1%) patients in group H and 51(69.9%) patients in group NH, with an average age of 60.3 ± 8.1 years. The patients in Group H exhibited significantly longer 5R-STS times and serious OFI compared to those in Group NH. Compared to Group NH, Group H exhibited significantly higher SP in the sitting position (21.8% vs 16.7%; P < 0.001*), while no significant differences were observed in the upright, flexion, extension, and supine MRI positions (all P values > 0.05). In Group H, "instability" was recognized in 77.3% of patients using S-MR versus 40.9% patients using FE (P < 0.001); While in Group NH, no significant difference was observed in the incidence of "instability" between FE and s-MR (37.3% vs. 31.4%, P = 0.53). Overall, a significantly higher incidence of instability was found in Group H compared to Group NH (77.3% vs .37.3%, P < 0 .001*).

CONCLUSIONS

DLS with a high intensity within the interspinous ligaments is a distinct subgroup associated with segmental instability, the combination of 5R-STS and S-MR should be regarded as the most clinically relevant approach for assessing OFI and lumbar instability.

Whether the potential degree of cervical instability and cervical muscle degeneration in patients with cervical spondylosis radicular affect the efficacy of cervical traction

To explore whether the potential instability of the cervical spine and cervical muscle degeneration in patients with cervical spondylotic radiculopathy (CSR) affect the efficacy of cervical traction, and whether cervical traction can aggravate the potential instability of the cervical spine. We divided the 113 recruited CRS patients into three groups based on the differences in horizontal displacement and abnormal angle, and measured the degree of cervical muscle degeneration in the patients through MRI. Considering functional scores, VAS, NDI and PCS scores of the three groups post-treatment were significantly improved. Through the intergroup analysis, we found that the improvement in functional scores in the mild and moderate instability trend groups was better than that in the severe group. Through MRI measurements, we found that the degree of cervical muscle degeneration was significantly increased in the severe instability trend group. Regarding the changes in X-Ray imaging parameters pre- and post-treatment, no significant differences were observed pre- and post-treatment. For patients with CSR, the more serious their predisposition for cervical instability was, the more severe the degree of cervical muscle degeneration was, which means the worse the curative effect was, but cervical traction did not aggravate the potential degree of cervical instability.

Segmental vertebral three-dimensional motion in patients with L4 isthmic spondylolisthesis under weight-bearing conditions

OBJECTIVE

To investigate in vivo 6-degree-of-freedom (DOF) vertebral motion in patients with isthmic spondylolisthesis (IS) during various functional weight-bearing activities.

METHODS

Fifteen asymptomatic volunteers (mean age 54.8 years) and fourteen patients with IS at L4-5 (mean age 53.4 years) were recruited. The positions of the vertebrae (L4-L5) in the supine, standing, flexion-extension, left-right twisting and left-right bending positions were determined using previously described CT-based models and dual fluoroscopic imaging techniques. Local coordinate systems were established at the center of the anterior vertebra of L4 isthmic spondylolisthesis (AIS), the posterior lamina of L4 isthmic spondylolisthesis (PIS) and the center of the L5 vertebra to obtain the 6DOF range of motion (ROM) at L4-L5 and the range of motion (ROM) between the AIS and the PIS.

RESULTS

The translation along the anteroposterior axis at L4-L5 during flexion-extension, left-right bending and left-right twisting was significantly greater than that of the healthy participants. However, the translation along the mediolateral axis at L4-L5 presented paradoxical motion under different positions: the ROM increased in the supine-standing and flexion-extension positions but decreased in the left-right bending and left-right twisting positions. The separation along the anteroposterior axis during flexion was significantly greater than that during standing, on average, reaching more than 1 mm. The separation along the mediolateral axis during standing, flexion and extension was significantly greater than that in the supine position.

CONCLUSIONS

This study revealed the occurrence of displacement between the AIS and PIS, primarily in the form of separation during flexion. Symptomatic patients with isthmic spondylolisthesis exhibit intervertebral instability, which might be underestimated by flexion-extension radiographs.

Factors leading to open revision surgery after trans-sacral canal plasty for lumbar spine disease

Trans-sacral canal plasty (TSCP) is a minimally invasive lumbar spine surgery under local anaesthesia. TSCP is expected to be effective regardless of whether the patient has had previous surgery. However, there are cases in which open revision surgery is required after TSCP. This study aimed to identify risk factors for open revision surgery after TSCP in order to determine surgical indications and limitations. A retrospective case-control study was conducted in patients who underwent TSCP for lumbar spine disease. Data of 112 patients were analysed. During an observation period of 7-23 months, 34 patients (30.4%) required open revision surgery and 78 (69.6%) did not. The following patient background characteristics were investigated: age, sex, body mass index (BMI), diagnosis, history of spine surgery and the institution where the surgery was performed. Comorbidities were scored using the Elixhauser Comorbidity Index. Preoperative imaging parameters were investigated, including the lesion level (L4/5, L5/S1, other), presence of intervertebral instability, dural sac area, presence of bony stenosis and presence of epidural lipoma. Multivariate analysis revealed that intervertebral instability (odds ratio 2.56, confidence interval 1.00-6.51, p = 0.046) and a narrow dural sac area (odds ratio 0.98, confidence interval 0.97-0.99, p = 0.002) were significant risk factors for open revision surgery after TSCP.

The effect of suboccipital muscle dysfunction on the biomechanics of the upper cervical spine: a study based on finite element analysis

OBJECTIVE

Muscle dysfunction caused by repetitive work or strain in the neck region can interfere muscle responses. Muscle dysfunction can be an important factor in causing cervical spondylosis. However, there has been no research on how the biomechanical properties of the upper cervical spine change when the suboccipital muscle group experiences dysfunction. The objective of this study was to investigate the biomechanical evidence for cervical spondylosis by utilizing the finite element (FE) approach, thus and to provide guidance for clinicians performing acupoint therapy.

METHODS

By varying the elastic modulus of the suboccipital muscle, the four FE models of C0-C3 motion segments were reconstructed under the conditions of normal muscle function and muscle dysfunction. For the two normal condition FE models, the elastic modulus for suboccipital muscles on both sides of the C0-C3 motion segments was equal and within the normal range In one muscle dysfunction FE model, the elastic modulus on both sides was equal and greater than 37 kPa, which represented muscle hypertonia; in the other, the elastic modulus of the left and right suboccipital muscles was different, indicating muscle imbalance. The biomechanical behavior of the lateral atlantoaxial joint (LAAJ), atlanto-odontoid joint (ADJ), and intervertebral disc (IVD) was analyzed by simulations, which were carried out under the six loadings of flexion, extension, left and right lateral bending, left and right axial rotation.

RESULTS

Under flexion, the maximum stress in LAAJ with muscle imbalance was higher than that with normal muscle and hypertonia, while the maximum stress in IVD in the hypertonic model was higher than that in the normal and imbalance models. The maximum stress in ADJ was the largest under extension among all loadings for all models. Muscle imbalance and hypertonia did not cause overstress and stress distribution abnormalities in ADJ.

CONCLUSION

Muscle dysfunction increases the stress in LAAJ and in IVD, but it does not affect ADJ.

Determining a relative total lumbar range of motion to alleviate adjacent segment degeneration after transforaminal lumbar interbody fusion: a finite element analysis

BACKGROUND

A reduction in total lumbar range of motion (ROM) after lumbar fusion may offset the increase in intradiscal pressure (IDP) and facet joint force (FJF) caused by the abnormally increased ROM at adjacent segments. This study aimed to determine a relative total lumbar ROM rather than an ideal adjacent segment ROM to guide postoperative waist activities and further delay adjacent segment degeneration (ASD).

METHODS

An intact L1-S1 finite element model was constructed and validated. Based on this, a surgical model was created to allow the simulation of L4/5 transforaminal lumbar interbody fusion (TLIF). Under the maximum total L1-S1 ROM, the ROM, IDP, and FJF of each adjacent segment between the intact and TLIF models were compared to explore the biomechanical influence of lumbar fusion on adjacent segments. Subsequently, the functional relationship between total L1-S1 ROM and IDP or total L1-S1 ROM and FJF was fitted in the TLIF model to calculate the relative total L1-S1 ROMs without an increase in IDP and FJF.

RESULTS

Compared with those of the intact model, the ROM, IDP, and FJF of the adjacent segments in the TLIF model increased by 12.6-28.9%, 0.1-6.8%, and 0-134.2%, respectively. As the total L1-S1 ROM increased, the IDP and FJF of each adjacent segment increased by varying degrees. The relative total L1-S1 ROMs in the TLIF model were 11.03°, 12.50°, 12.14°, and 9.82° in flexion, extension, lateral bending, and axial rotation, respectively.

CONCLUSIONS

The relative total L1-S1 ROMs after TLIF were determined, which decreased by 19.6-29.3% compared to the preoperative ones. Guiding the patients to perform postoperative waist activities within these specific ROMs, an increase in the IDP and FJF of adjacent segments may be effectively offset, thereby alleviating ASD.

A possible correlation between facet orientation and development of degenerative cervical spinal stenosis

BACKGROUND

Previous studies have demonstrated the relationship between sagittal facet orientation and cervical degenerative spondylolisthesis. However, the associations between facet orientation and cervical spinal stenosis (CSS) have rarely been studied.

METHODS

One hundred twenty patients with CSS (CSS group) and 120 healthy participants (control group) were consecutively enrolled. The cervical facet angles and anteroposterior diameter (A-P diameter) of spinal canal at each subaxial cervical levels were measured using axial magnetic resonance imaging. The intersection angle of the midsagittal line of the vertebra to the facet line represents the orientation of the facet joint.

RESULTS

The facet angles on the right side at C2- C3 and C3-C4 in CSS group and at C2- C3 in control group had significantly higher values than those of the other sides. Besides, the facet angles and A-P diameter of spinal canal in CSS group were significantly smaller than those in control group at all levels (p < 0.05).

CONCLUSIONS

Our study demonstrated that patients with CSS have smaller axial cervical facet joint angles compared to the healthy individuals. Further studies are needed to elicit the specific underlying mechanism between sagittalization of the cervical facet joints and the pathology of CSS.

Relationship between paravertebral muscle degeneration and spinal-pelvic sagittal parameters in patients with lumbar disc herniation

Lumbar disc herniation (LDH) is a clinically common degenerative disease of the spine, and spinal-pelvic sagittal balance and paravertebral muscle degeneration have been a research focus in recent years. To explore the relationship between the degeneration of paravertebral muscle and the changes in the spinal-pelvic sagittal parameters in LDH patients, 105 LDH patients (experimental group) and 63 healthy volunteers (control group) hospitalized in Ordos Central Hospital from January 2020 and January 2023 were included as study subjects. All the patients underwent lumbar magnetic resonance imaging and spinal X-ray using uniform criteria. The correlation between the paravertebral muscle and sagittal-pelvic sagittal parameters of the patients with LDH was obtained from two imaging examinations, and the data were organized and grouped to explore the correlation between these parameters. No significant difference in general data existed between the groups (P > 0.05). In the L4/5 LDH patients group, the ratio of fat infiltration (FIR) in the healthy side [multifidus (MF) and erector spinae (ES)] was negatively correlated with the lumbar lordosis (LL) (r = -0.461, r = -0.486, P < 0.05). The relative cross-sectional area (RCSA) of the bilateral MF was positively correlated with the pelvic tilt (r = 0.549, r = 0.515, P < 0.05). The bilateral ES RCSA was negatively correlated with the sagittal vertical axis (r = -0.579, r = -0.621, P < 0.05). A positive correlation existed between the RCSA and thoracic kyphosis in the healthy side ES (r = 0.614, P < 0.05). In the L5/S1 LDH patients group, a negative correlation existed between the FIR and LL in the healthy side ES (r = -0.579, P < 0.05). Thus, the paravertebral muscle parameters were correlated with the spinal-pelvic sagittal parameters in the patients with LDH.

Enhanced grading methods for lumbar paraspinal fat infiltration and its prognostic value in predicting lumbar disc herniation

BACKGROUND

The simplified 3-grade system for measuring fat infiltration in the paraspinal muscles is widely utilized. In comparing our proposed 4-grade system to the existing 3-grade system, we evaluated its impact on results and particularly its ability to predict disc herniation, ultimately highlighting deficiencies in the latter. The objective of this investigation was to validate the efficacy of our newly proposed semi-quantitative simplified 4-grade system for assessing fat infiltration, as compared to the existing literature-based simplified 3-grade system, in terms of their predictive value for lumbar disc herniation.

METHODS

Infiltration of the right and left lumbar multifidus and erector spinae muscles were assessed using a semi-quantitative 3- and 4-grade fat infiltration system on axial magnetic resonance imaging sections at the L3-S1 level in all subjects, with comparison of results between groups. The correlation between these grading systems and lumbar disc herniation was investigated.

RESULTS

The simplified 3-degree system for measuring fat infiltration was not effective in predicting lumbar disc herniation (p > 0.05), while the 4-degree system proved to be useful in predicting it (p < 0.05). In both grading systems, females were found to have a higher risk of lumbar disc herniation than males (p < 0.05), and the risk increased with age and body mass index (BMI) (p < 0.001).

CONCLUSIONS

It was observed that using the 4-grade fat infiltration system to determine the level of fat infiltration in the paraspinal muscles is more effective in predicting lumbar disc herniation compared to the 3-grade system. The 4-grade fat infiltration grading system proves to be an efficient semi-quantitative method that can replace the simplified 3-grade system.

Evaluation of the degeneration of the multifidus and erector spinae muscles in patients with low back pain and healthy individuals

BACKGROUND

Although several studies have been conducted to determine the cause of low back pain (LBP), a sufficient correlation has not been found between research findings and symptoms. Therefore there seems to be a need for studies to explain the relationship between pain and morphological changes in the paraspinal muscles of patients with LBP through comparisons with healthy control subjects.

OBJECTIVE

The aim of this study was to examine degeneration in the lumbar musculus multifidus (LMF) and lumbar musculus erector spinae (LES) muscles in patients with chronic LBP with non-radiculopathy lumbar disc herniation (LDH), patients with mechanical LBP, and healthy individuals.

METHODS

The study included 35 patients with mechanical LBP, 38 patients with non-radiculopathy LDH, and a control group of 36 healthy participants. In all patients and the control group, evaluations were made on axial magnetic resonance imaging slices at L3-S1 level of the LMF and LES cross-sectional areas (CSA), total CSA (TCSA = LMF+LES), fat infiltrations and asymmetries.

RESULTS

The mean CSA values of the right and left LMF and LES showed significant differences between the groups (p< 0.001, p= 0.002, p= 0.002, p= 0.010, respectively). Fat infiltrations showed a difference between the right-left LMF and left LES groups (p= 0.007, p< 0.001, p= 0.026, respectively). Asymmetry was not observed between the CSA and TCSA of the right and left sides.

CONCLUSION

A correlation was found between fat infiltration in the LMF and mechanical LBP and LDH. However, no significant correlation was determined between LBP and the CSA and TCSA of the LMF and LES. This was thought to be due to an incorrect result of CSA and TCSA in the evaluation of muscle mass. Therefore, for a more accurate evaluation of muscle mass, it can be considered necessary to measure muscle atrophy associated with fat infiltration or functional CSA.