Irregular Alteration of Facet Orientation in Lumbar Segments: Possible Role in Pathology of Lumbar Disc Herniation in Adolescents

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.

Machine Learning Prediction Model and Risk Factor Analysis of Reoperation in Recurrent Lumbar Disc Herniation Patients After Percutaneous Endoscopic Lumbar Discectomy

OBJECTIVE

To investigate the risk factors of reoperation after percutaneous endoscopic lumbar discectomy (PELD) due to recurrent lumbar disc herniation (rLDH) and to establish a set of individualized prediction models.

METHODS

Patients who underwent PELD successfully from January 2016 to February 2022 in a single institution were enrolled in this study. Six methods of machine learning (ML) were used to establish an individualized prediction model for reoperation in rLDH patients after PELD, and these models were compared with logistics regression model to select optimal model.

RESULTS

A total of 2603 patients were enrolled in this study. 57 patients had repeated operation due to rLDH and 114 patients were selected from the remaining 2546 nonrecurrent patients as matched controls. Multivariate logistic regression analysis showed that disc herniation type (P < .001), Modic changes (type II) (P = .003), sagittal range of motion (sROM) (P = .022), facet orientation (FO) (P = .028) and fat infiltration (FI) (P = .001) were independent risk factors for reoperation in rLDH patients after PELD. The XGBoost AUC was of 90.71%, accuracy was approximately 88.87%, sensitivity was 70.81%, specificity was 97.19%. The traditional logistic regression AUC was 77.4%, accuracy was about 77.73%, sensitivity was 47.15%, specificity was 92.12%.

CONCLUSION

This study showed that disc herniation type (extrusion, sequestration), Modic changes (type II), a large sROM, a large FO and high FI were independent risk factors for reoperation in LDH patients after PELD. The prediction efficiency of XGBoost model was higher than traditional Logistic regression analysis model.

Sacralization may be associated with facet orientation and tropism but not degenerative changes of the lumbar vertebrae

Purpose

In this retrospective study, we aimed to investigate the possible effects of transitional vertebra anatomy on facet joint tropism and orientation by evaluating lumbar magnetic resonance imaging (MRI) studies performed at our institution.

Material and methods

We included 84 patients with sacralization of the L5 vertebra and an equal number of patients with a radiology report within normal limits as the control group in our study. We compared facet tropism (FT) and orientation between both groups.

Results

In both the sacralization group and the control group, the facet orientation angle showed a significant increasing trend from the L1-L2 level to the L5-S1 level (p < 0.001). The orientation angle of the L5-S1 level was higher in the sacralization group compared to the control group (p < 0.01). In the evaluation of FJ orientation between the sacralization and control groups, we found that coronal orientation was significantly more frequent at the L5-S1 level in the sacralization group. When the 2 groups were compared with regard to tropism at each spinal level, the sacralization group had a significantly higher FT frequency at the L5-S1 level (p < 0.001).

Conclusions

To our knowledge, this is the first study to evaluate the relationship between sacralization and facet joint tropism. However, there were no relationships between facet degeneration, disc degeneration/herniation, and sacralization. Our results indicate that, although patients with sacralization and controls had similar characteristics in most assessments, they demonstrated significant differences at the L5-S1 level in terms of orientation and tropism.

Three-dimensional digital measurement of the facet joint in normal and lumbar intervertebral disc herniation aged 13-18 years

BACKGROUND

Lumbar facet joint is an important element of spinal "three-joint complex". Whether there is a relationship between strange structure of facet joint and adolescent lumbar disc herniation (ALDH) is nonetheless controversial, and the current research is mainly centered on adults.

OBJECTIVE

To find out the normal lumbar facet joints between 13 and 18 years old to provide anatomical basis for early diagnosis and therapy of lumbar disc herniation.

METHODS

CT imaging information of 32 sufferers with lumbar disc herniation aged from 13 to 18 years old in Inner Mongolia have been collected as the ALDH group, and 62 wholesome subjects in the equal period had been chosen as the normal group. Uncooked records of continuous scanning lumbar tomography pix were imported into MIMICS 21.0 for evaluation and size in DICOM format. The parameters include facet joint height, facet joint width, et al.

RESULTS

1. The left and right transverse angle of L₅S₁ segment in the ALDH group were (52.41 ± 9.2) ° and (55.99 ± 10.91) ° (P < 0.05), and the differences were statistically significant. The right side is larger than the left side. 2. Facet joint thickness in L₃-L₅ segment of the normal group was significantly higher than that of male (1.63 ± 0.32) mm than that of female (1.38 ± 0.25) mm; In 16-18 years old group, comparison of facet joint cross-sectional area was statistically significant (22.1 ± 3.04) mm² in male than (18.92 ± 3.71) mm² in female. 3. In comparison between normal and ALDH group, there was significant difference in L_3-4 transverse angle (P < 0.05), L_4-5 facet joint height and facet joint thickness (P < 0.05), L₅S₁ facet joint thickness and transverse angle (P < 0.05).

CONCLUSION

When ALDH occurs in the L₅S₁ segment, there is a substantial difference between the left and right sides of the transverse angle, and there is a difference in the thickness and the facet joint cross-sectional area between males and females, which is generally larger in males than in females. Facet joint height is larger, transverse angle of left and right is asymmetric, inferior articular process is larger, and facet joint thickness is smaller can indicate that lumbar disc herniation is effortless to occur.

The relationship between facet tropism and cervical disc herniation

Many studies have demonstrated the association between facet tropism and disc herniation in the lumbar spine. Some of them found that lumbar disc herniation was on the side of the more sagittal facet joint interface. However, little is understood about the association of facet tropism with disc herniation in the cervical spine. As the relationship between the facet orientation and the side of cervical disc herniation (CDH) is unclear, the purpose of this study is to investigate that relationship. Ninety-six patients with single-level CDH (C4-C5, C5-C6 or C6-C7) were included in the CDH group of this study. Another 50 age-matched and gender-matched healthy participants who accepted physical examinations were enrolled as the control group. The cervical facet angles of two sides were measured using axial computed tomography (CT). The intersection angle of the midsagittal line of the vertebra to the facet line represents the facet angle. Facet tropism was defined as the angular difference of 7º between the left and the right sides. Facet tropism angle was recorded as the absolute value of the difference of facet angles between two sides. There were 20 herniations at C4-C5 level, 50 herniations at C5-C6 level and 26 herniations at C6-C7 level. The present study showed that more cases in the CDH group had facet tropism than did those in the control group at C4-C5, C5-C6 and C6-C7 level (p = .021, p = .001, p = .015, respectively). The facet tropism angles in the CDH group were significantly bigger than those in the control group at C4-C5, C5-C6 and C6-C7 level (p = .001, p = .002, p = .028, respectively). In the CDH group, the facet angles on the herniated side were found to be significantly bigger than those on the healthy side at C4-C5, C5-C6 and C6-C7 level (p = .000, p = .000, p = .037, respectively). The findings of this present study suggest that facet tropism is associated with the disc herniation in the cervical spine. We also found that cervical disc herniates towards the side of the bigger facet angle with respect to the sagittal plane. There is a need for future studies to verify the biomechanical impact of facet tropism on CDH.

Association Between Irregular Alteration of Facet Orientation and Degenerative Lumbar Spondylolisthesis

BACKGROUND

Numerous studies have reported that irregular alteration of facet orientation (IAFO) is associated with lumbar disc herniation (LDH) in adolescents. The present study investigated the association between IAFO and degenerative lumbar spondylolisthesis (DLS) at the L4-5 segment.

METHODS

Forty-two adults with DLS were enrolled in this study. Facet angles were measured in the bone window of the computed tomography scan. Large-small-large (LSL) was defined as a type of IAFO that includes the angle of facet joints at L4-5, which is smaller than that in L3-4 and L5-S1 segments. Fifty subjects with LDH at L4-5 served as controls. Data were analyzed using logistic regression analysis.

RESULTS

In the 42 patients and 50 controls, the facet angle was measured at 276 levers from L3-4 to L5-S1. The mean included angles of L3-4, L4-5, and L5-S1 were 71.5 ± 19.97°, 51.79 ± 21.43°, and 102.89 ± 20.37°, respectively, in the DLS group and 77.48 ± 17.24°, 91.00 ± 17.24, and 102.94 ± 19.75°, respectively, in the control group. LSL was detected in 38 of 42 subjects (90.5%) in the DLS group, compared with 9 of 50 (18.0%) in the controls. The sagittal orientation facet joint in L4-5 was associated with DLS (odds ratio [OR], 26.24; 95% confidence interval [CI], 13.30-155.35; P = 0.000). The facet in L3-4 with a more coronal orientation than that in L4-5 was also correlated with DLS (OR, 33.68; 95% CI, 9.86-115.06; P = 0.000). There was no correlation between the facet in L5-S1 and DLS in L4-5 (P = 0.999), but there was a strong relationship between LSL in L3-5 and DLS in L4-5 (OR, 43.278; 95% CI, 12.303-152.232; P = 0.000).

CONCLUSIONS

The data presented here demonstrate that LSL, which is an irregular alteration of facet joint orientation, is associated with the degenerative lumbar spondylolisthesis at L4-5.

Facet Sagittal Orientation: Possible Role in the Pathology of Degenerative Lumbar Spinal Stenosis

STUDY DESIGN

A retrospective case-control study.

OBJECTIVE

This study aimed to elucidate the association between facet joint orientation and degenerative lumbar spinal stenosis (DLSS).

SUMMARY OF BACKGROUND DATA

Many studies have demonstrated the relationship between sagittal facet orientation and degenerative lumbar spondylolisthesis. However, the associations between facet orientation and DLSS have rarely been studied.

METHODS

Ninety-one age-matched and sex-matched patients with DLSS (LSS group) and 91 control participants were consecutively enrolled. Their lumbar facet angles and the dural sac cross-sectional area at L2-L3, L3-L4, L4-L5, and L5-S1 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 left side or right side of the LSS group were significantly smaller than the respective ones of the control group. Outcomes of the groups revealed significantly and consistently increasing facet angles from L2-L3 to L5-S1. The dural sac cross-sectional area of the LSS group had significantly smaller measurements values than that of the control group at L2-L3, L3-L4, L4-L5, and L5-S1.

CONCLUSION

Sagittalization of lumbar facet joints was considered to be a risk factor for DLSS and may play a role in the pathology of DLSS.

LEVEL OF EVIDENCE

3.

The Effects of Orientation of Lumbar Facet Joints on the Facet Joint Contact Forces: An In Vitro Biomechanical Study

STUDY DESIGN

A biomechanical human cadaveric study.

OBJECTIVE

The aim of this study was to measure L2-L3 facet joint contact forces in a flexibility test using thin film electroresistive sensors, and facet joint orientation on computed tomographic (CT) scan images, to examine the effects of orientation of lumbar facet joint on the facet joint contact forces.

SUMMARY OF BACKGROUND DATA

Biomechanically, the bilateral facet joints play a critical role in maintaining stability of the lumbar spine. The effect of orientation of lumbar facet joints on the contact forces remains unknown.

METHODS

Eight human cadaveric lumbar spine specimens (L2-L3) were tested by applying a pure moment of ±7.5 Nm in three directions of loading (flexion-extension, lateral bending, and axial rotation) with and without a follower preload of 300 N. The orientation of the lumbar facet joints at the L2-L3 was measured on axial CT scans. Bilateral facet contact forces were measured during flexibility tests using thin film electroresistive sensors (Tekscan 6900).

RESULTS

The average total peak facet loads was 66 N in axial rotation, 27 N in extension, and 20 N in lateral bending under a pure moment. Under a pure moment with a follower preload of 300 N, the average total peak facet loads was 53 N in axial rotation, 43 N in extension, and 24 N in lateral bending. The facet joint forces were correlated positively and significantly with the orientation in all directions with and without a compressive follower preload (P < 0.05). In addition, the facet joint contact forces at neutral position with a follower preload were correlated positively with the orientation (rs = 0.759, P = 0.001).

CONCLUSION

This study identified that the greater coronal orientation of lumbar facet joints is, the higher the facet joint contact forces are.

LEVEL OF EVIDENCE

3.

The Role of the Features of Facet Joint Angle in the Development of Isthmic Spondylolisthesis in Young Male Patients with L5-S1 Isthmic Spondylolisthesis

OBJECTIVE

To investigate facet tropism and its role in development of lumbar isthmic spondylolisthesis (IS) in young men.

METHODS

From March 2013 to May 2016, bilateral facet joint angles were measured axially at L3-4, L4-5, and L5-S1 on lumbar computed tomography (CT) in 97 participants (46 patients with IS and 51 control subjects) 20-29 years old. A difference between the 2 corresponding facet angles of <6° was classified as no tropism; a difference of 6°-12°, moderate tropism; and a difference of >12°, severe tropism.

RESULTS

We measured 276 facet angles from 46 patients with IS and 306 facet angles from 51 control subjects. For patients with IS, there was no tropism in 43.5% (n = 20), moderate tropism in 50% (n = 23), and severe tropism in 6.5% (n = 3) at L3-4. For L4-5, there was no tropism in 28.3% (n = 13), moderate tropism in 60.9% (n = 28), and severe tropism in 10.9% (n = 5). For L5-S1, there was no tropism in 32.6% (n = 15), moderate tropism in 39.1% (n = 18), and severe tropism in 28.3% (n = 13). For the control group, there was no tropism in 86.3% (n = 44), moderate tropism in 13.7% (n = 7), and no severe tropism at L3-4. For L4-5, there was no tropism in 80.4% (n = 41), moderate tropism in 17.6% (n = 9), and severe tropism in 1.9% (n = 1). For L5-S1, there was no tropism in 68.6% (n = 35), moderate tropism in 29.4% (n = 15), and severe tropism in 1.9% (n = 1).

CONCLUSIONS

Facet angle tropism is seen in a high proportion of patients with IS and seems to be a predisposing factor in the etiology of IS.

Evaluation and management of lower back pain in young athletes

Lower back pain in young athletes is a common problem. The prevalence of back pain from different causes in adolescent age group is between 20% and 30%. However, the incidence of low back pain in young athletes varies widely in different sports. Overuse injuries are the most common cause of low back pain in young athletes. In case of overuse injuries, the cause and effect relationship between back pain and specific condition is often difficult to establish. In adolescent athletes, the most common underlying identified cause of low back pain is lumbar spondylolysis. During adolescent growth spurt, the severity of the pain generally correlates with adolescent growth spurt. Participation in sports starting at an early age and for a longer duration tends to increase the risk for back pain. Numerous conditions cause low back pain in athletes. These include acute trauma, chronic overuse or repetitive trauma, and referred pain. Our focus in here will be on selected conditions that cause recurrent or chronic low back pain.

The Effect of Lumbar Disc Herniation on Spine Loading Characteristics during Trunk Flexion and Two Types of Picking Up Activities

The main purpose of this study was to investigate the compensatory response of the muscle activities of seventeen major muscle groups in the spinal region, intradiscal forces of the five lumbar motion segment units (MSUs), and facet forces acting on the ten lumbar facet joints in patients with lumbar disc herniation (LDH). Twenty-six healthy adults and seven LDH patients performed trunk flexion, ipsilateral picking up, and contralateral picking up in sequence. Eight optical markers were placed on the landmarks of the pelvis and spinal process. The coordinates of these markers were captured to drive a musculoskeletal model to calculate the muscle activities, intradiscal forces, and facet forces. The muscle activities of the majority of the seventeen major muscle groups were found increases in LDH patients. In addition, the LDH patients displayed larger compressive forces and anteroposterior forces on all the five lumbar MSUs and more lumbar facet inventions on most facet joints. These findings suggest that the LDH patients demonstrate compensatory increases in the most trunk muscle activities and all spinal loads. These negative compensatory responses increase the risk of the aggravation of disc herniation. Therefore, treatment should intervene as earlier as possible for the severe LDH patients.

The investigation of the role of the facet joint angle in the development of L5-S1 spondylolysis in young men

OBJECTIVES

This study aims to evaluate facet tropism in younger patients with lumbar spondylolysis and to investigate the role of facet tropism in the development of spondylolysis.

PATIENTS AND METHODS

Between February 2013 and December 2015, a total of 102 male patients with bilateral L5 pars defect including 53 with spondylolysis and 49 control subjects were included in this case-control study. The facet joint angles were measured bilaterally and axially at the level of L3-4, L4-5, L5-S1 using computed tomography (CT). The classification was made as follows: A difference between two reciprocal facet joint angles of <6° indicated no tropism, 6°-12° indicated moderate tropism, and >12° indicated severe tropism.

RESULTS

A total of 612 angles including 318 facet joint angles from 53 patients with spondylolysis and 294 facet joint angles from 49 control subjects were measured. L3-4 measurements in the control group showed no tropism in 87.8% (n=43), moderate tropism in 12.2% (n=6), and severe tropism in 0% (n=0). L4-5 measurements in control group showed no tropism in 79.6% (n=39), moderate tropism in 20.4% (n=10), and severe tropism in 0% (n=0). L5-S1 measurements in the control group showed no tropism in 69.4% (n=34), moderate tropism in 28.6% (n=14), and severe tropism in 2.0% (n=1). The mean facet joint angles in the spondylosis group were 32.9±5.1°, 37.5±5.4°, and 41.2±7.8° at the levels of L3-4, L4-5, and L5-S1, respectively. The mean facet joint angles of the control group were 33.2±5.7°, 39.7±4.9°, and 42.2±4.9° at the levels of L3-4, L4-5, and L5-S1, respectively, indicating no significant difference between the right and left mean facet joint angles between the groups (p>0.05). The frequency of facet tropism and the difference between right and left facet joint angles for all three levels were significantly higher in the spondylolysis group (p<0.05). Facet tropism at the level of L5-S1 was significantly more frequent than facet tropism at L3-4 level (p<0.05).

CONCLUSION

Our study results show that the rate of facet joint tropism is higher in the patients with spondylolysis, suggesting that facet tropism seems to play a role in the etiology of spondylolysis as a predisposing factor.