The Impact of Spinopelvic Alignment on the Facet Joint Degeneration

Abstract

Study Design

Retrospective Cohort.

Objectives

This study aims to evaluate the relations between facet joint degeneration (FD) and sagittal spinopelvic parameters. Second, the association of FD with degenerative disc disease (DDD) and lumbar disc herniations (LDH) was assessed.

Methods

The radiologic data of 192 patients was retrospectively analyzed. Total, proximal, and distal lumbar lordosis (LL, PLL, and DLL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and sacral table angle (STA) were measured on lumbar x-ray plates. DDD and FD was graded on the MRI images. The apex of lumbar lordosis and PI-LL imbalance were noted in each patient. Correlation analyses were performed.

Results

Age and body mass index (BMI) were correlated with FD. LL and DLL are positively associated with upper-level FDs (L1-2 and L2-3) (P < 0,05). PLL were positively associated with lower level FD (L5-S1) (P < 0,05). A significant increase in PI was associated with FD in L2-3 and L4-5. A larger PT was found in FD in L4. The PI-LL imbalance was not correlated with the FD. Correlation between DDD and LDH and FD was observed in each level (P < 0,01). The level of FD is not affected by the apex of the curve.

Conclusion

Age and BMI have a direct impact on FD. However, spinopelvic parameters influence the severity of FD rather than its occurrence. In addition to the effects of lumbar lordosis as a single entity, it is essential to consider separately the effects of proximal and distal lumbar lordosis at the FD level.

Keywords

facet degeneration sagittal spinopelvic parameters degenerative disc disease lumbar disc herniation PI-LL imbalance apex of lumbar lordosis

Introduction

Low back pain (LBP) is the most prevalent pain condition that affects people of all ages worldwide. The lifetime prevalence of LBP in adults in the United States is estimated to range from 65 to 80%.¹ The prevalence of lumbar facet joint (FJ)-related LBP is estimated to range between 15 and 45%, indicating that facet degeneration (FD) is a potential cause of LBP.²

Osteoarthritis is the most prevalent form of facet pathology and a frequent cause of pain.^3,4 Furthermore, arthritic degeneration of the lumbar FJs has even been cited as a potential cause of persistent LBP in patients with lumbar disc herniation (LDH) who have undergone minimally invasive discectomy.⁵ According to Eubanks et al., degenerative changes are universal, with the highest prevalence at the L4-5 and L5-S1 spinal level.⁶ The FJ’s play a crucial role in load transmission by providing a posterior load-bearing aid and stabilizing the motion segment in flexion and extension. By limiting axial rotation, they participate in the mechanism of rotational kinematics.⁷ Although there are few publications in the literature investigating the relationship between FD, degenerative disc disease (DDD), and spinopelvic parameters, the correlative relationships between them are still unclear. The aim of this study is to elucidate the possible correlative relationships between these parameters (8-10).

Methods

This study was a retrospective data analysis conducted at a single center between March and September 2021. The Institutional Review Board of our institution approved this research (Protocol No. 2022-45). Informed consent was obtained from all participants. The medical records of 192 patients who reported low back pain were retrospectively examined. Inclusion criteria were the following:¹ Outpatients over the age of 18 suffering from symptomatic low back pain² patients with lateral upright standing radiographs displaying both the thoracic 12 vertebrae and the femoral heads, in addition to lumbar magnetic resonance imaging (MRI)s. The exclusion criteria were the following:¹ patients undergoing pelvic, spinal, or lower extremity surgery;² patients suffering from spinal deformities such as scoliosis and isthmic spondylolisthesis.³ Patients suffering from inflammatory and neuromuscular conditions⁴ patients with hip or knee arthroplasty or other lower limb realignment surgery.⁵ patients with limb length disparities. Of the 248 subjects, 56 patients who met the exclusion criteria and had inadequate radiographs or no MRIs were excluded. The remaining 192 patients meeting the inclusion criteria were recruited for this study. First, spinopelvic parameters including total lumbar lordosis (LL), proximal lumbar lordosis (PLL), distal lumbar lordosis (DLL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and sacral table angle (STA) were measured on the lateral upright standing radiographs using Surgimap® Software (Nemaris Inc., New York, NY, USA) by two spine surgeons simultaneously. When measuring spinopelvic parameters, it has been demonstrated that standing upright lateral radiographs yield comparable results to standing whole spine radiographs.¹¹ All measurements were performed with the joint decision of both experts. LL is the angle between the lines drawn parallel to the lower endplate of the T12 vertebrae and the upper-endplate of the S1 vertebrae. PLL is the angle between the lines drawn parallel to the lower endplate of the T12 vertebra and the lower endplate of the L3 vertebra. DLL is the angle between the lines drawn parallel to the upper endplate of the L4 vertebra and the upper endplate of the S1 vertebra. So, the sum of PLL and DLL is equal to LL. PI is the angle between the line perpendicular to the midpoint of the sacral plate and the line drawn from this point to the bicoxofemoral line. PT is the angle between the vertical plane and the line joining the midpoint of the sacral plate and the bi-coxo-femoral axis. SS is the angle between the sacral endplate and the horizontal axis. STA is the angle between a line parallel to the sacral endplate and a line drawn to parallel the posterior aspect of the S1 vertebral body (Figure 1). In the sagittal plane, the apex (of lumbar lordosis) was defined as the most anterior lumbar vertebra or intervertebral disk.¹² L1 through L5 vertebrae were assigned numbers ranging from 1 to 5 to facilitate data collection and correlation analysis. When the apex was located on a disc between two vertebrae, the superior vertebra number was increased by .5. For instance, the apex was recorded as 4.5 when it was located on the disc between L4 and L5.

Figure 1.

Measurement of Spinopelvic parameters.

Second, based on axial T2 MRI sections, FD was graded at all lumbar levels in all patients according to the Weishaupt classification.¹³ Grade 0 and 1 facets were accepted as non degenerated (FD-) (n = 80), while grade 2 and 3 facets were accepted as degenerated (FD+) (n = 112). (Figure 2). Thus, patients were stratified into two groups according to the presence of FD.

Figure 2.

Facet joint evaluation. The Weishaupt system classifies facet joint degeneration into four grades: normal (0) to severe.³

Third, the degree of degeneration of each disc was evaluated according to the Pfirrmann classification.¹⁴ Then, the patients were stratified into 3 groups: the non-degenerative (ND) group (n = 44), the DDD group (n = 89), and the LDH group (n = 59). Grade 1 and 2 discs were defined as non-degenerating and included in the ND group. Grade 3-4-5 discs were accepted as degenerating and included in the DDD group. Patients with grade <3 and having disc herniation on MRI were included in the LDH group. Both FJ and disc evaluations were performed by the joint decision of a spine surgeon and radiologist with 10 years of experience. Then, statistical analyses were performed to investigate the differences between the groups.

Statistical Analysis

For statistical analysis, SPSS 26 (Statistical Package for the Social Sciences) was utilized. The study data were evaluated using descriptive statistical methods (mean, standard deviation, median, frequency, percentage, minimum, and maximum). The Shapiro-Wilk test and graphical analysis were used to examine the quantitative data’s conformity to a normal distribution. The Student t test was utilized to compare two groups of normally distributed quantitative variables, whereas the Mann-Whitney U test was utilized to compare two groups of non-normally distributed quantitative variables. For comparisons of quantitative variables with normal distribution between more than two groups, one-way analysis of variance was used, whereas Games-Howell test and Bonferroni corrected pairwise evaluations were used for pairwise comparisons. The Kruskal-Wallis and Dunn-Bonferroni tests were used to compare quantitative variables that lacked a normal distribution across more than two groups. Using the Pearson chi-square test, qualitative data were compared. Using Spearman’s correlation analysis, the relationships between quantitative variables were evaluated. Acceptable statistical significance was P < .05.

Results

DDD and FD were more frequently observed at distal lumbar levels. Distributions in level basis are given in Figure 3.

Figure 3.

DDD and FD rates in level basis.

When investigating the factors related with FD regardless of level, age and body mass index (BMI) were shown to be associated with FD among demographic factors, but only LL and PLL were associated with FD among spinopelvic parameters (P = .044 and P = .023). There was no correlation observed with other parameters (Table 1).

Table 1.

Comparison of Spinopelvic Parameters according to Facet Degeneration.

		Facet Degeneration		p
		No (n = 80)	Yes (n = 112)	p
Age	Avg ± Sd	29,29 ± 7,99	43,13 ± 13,93	^e 0.001**
Age	Median (Min-Max)	29 (13-50)	43 (16-77)	^e 0.001**
Sex	Female	47 (58,8)	68 (60,7)	^c 0.784
Sex	Male	33 (41,3)	44 (39,3)	^c 0.784
BMI	Avg ± Sd	23,61 ± 4,30	28,19 ± 451	^e 0.001**
BMI	Median (Min-Max)	23 (15,6-35,9)	28,3 (19,4-41,6)	^e 0.001**
LL	Avg ± Sd	49,53 ± 14,24	53,81 ± 14,53	^e 0.044*
LL	Median (Min-Max)	51,1 (18,1-84,4)	55,2 (7,6-89,9)	^e 0.044*
DLL	Avg ± Sd	33,17 ± 9,07	34,49 ± 10,03	^e 0.353
DLL	Median (Min-Max)	34,5 (15,1-52,3)	37,1 (4,6-54,9)	^e 0.353
PLL	Avg ± Sd	16,36 ± 9,21	19,33 ± 8,57	^e 0.023*
PLL	Median (Min-Max)	16,4 (-6,2-36)	19,9 (-7,1-38,2)	^e 0.023*
PI	Avg ± Sd	47,5 ± 10,15	49,2 ± 9,74	^e 0.242
PI	Median (Min-Max)	46,2 (23,9-74,6)	49,9 (24,8-76,4)	^e 0.242
PT	Avg ± Sd	13,31 ± 6,02	15,27 ± 7,38	^e 0,052
PT	Median (Min-Max)	13,6 (2,4-30)	14,3 (1,4-43,6)	^e 0,052
SS	Avg ± Sd	34,22 ± 8,02	33,85 ± 8,98	^e 0,770
SS	Median (Min-Max)	33,4 (15-52,5)	33,4 (7,5-68)	^e 0,770
STA	Avg ± Sd	103,56 ± 6	104,77 ± 4,95	^e 0,142
STA	Median (Min-Max)	102,8 (92,1-116,5)	104,9 (92,2-115,8)	^e 0,142

^aPearson Chi-Square Test ^eStudent-t Test *P < .05 **P < .01.

When we analyzed the effects of spinopelvic parameters on FD on a level-by-level basis, we discovered that LL and DLL had a significant relationship with upper level FD (P < .05; r = .143 at L1-2 and r = .142 at L2-3). High PLL is associated with lower level FD (P < .05; r = .172 at L5-S1). Increased PI was found in FD at the L2-3 and L4-5 levels (P < .05; r = .160 and r = 148). High PT is associated with FD at the L4-5 level (P < .05; r = .187). Other spinopelvic parameters yielded no significiant diferences (Table 2).

Table 2.

Statistical comparison of spinopelvic parameters and facet degeneration at each level.

		Facet Degeneration
		L1-2	L2-3	L3-4	L4-5	L5-S1
LL	r	0.143	0.142	0.077	0.077	0.138
LL	p	0,048*	0,049*	0,291	0289	0,056
DLL	r	0.170	0.146	0.099	0.047	0.062
DLL	p	0,018*	0,044*	0,171	0517	0,393
PLL	r	0.010	0.074	0.020	0.108	0.172
PLL	p	0,894	0309	0,782	0137	0,017*
PI	r	0.115	0.160	0.114	0.148	0.136
PI	p	0,114	0,027*	0,117	0040*	0,060
PT	r	0.071	0.121	0.128	0.187	0.126
PT	p	0,331	0094	0,076	0009**	0,082
SS	r	0.074	0.074	0.022	-0.001	0.040
SS	p	0,305	0308	0,763	0990	0,580
STA	r	0.042	0.063	0.101	0.104	0.085
STA	p	0,567	0385	0,164	0150	0,243

r = Spearman’s Correlation Coefficient *P < 0,05.

Neither the level of apex of lumbar curve nor PI-LL imbalance had no effect on FD (Table 3).

Table 3.

The level-based effect of the apex of the lumbar curve and the PI-LL mismatch on facet degeneration.

		Apex of Lumbar Lordosis				PI-LL
					HyperLordotic	Balanced	FlatBack
Level of Facet Joint	Degeneration	Avg ± Sd	Median (Min-Max)	^p	n (%)	n (%)	n (%)	^p
L1-2	No (n = 163)	3,37 ± 0,67	3 (2-5)	^a 0,054	54 (1,77)	80 (9,87)	29 (5,93)	^c 0,057
L1-2	Yes (n = 29)	3,09 ± 0,71	3 (1-5)		16 (9,22)	11 (1,12)	2 (5,6)
L2-3	No (n = 151)	3,36 ± 0,67	3 (2-5)	^a 0,433	50 (4,71)	75 (4,82)	26 (9,83)	^c 0,179
L2-3	Yes (n = 41)	3,23 ± 0,72	3 (1-5)		20 (6,28)	16 (6,17)	5 (1,16)
L3-4	No (n = 128)	3,36 ± 0,65	3 (2-5)	^a 0,611	43 (4,61)	64 (3,70)	21 (7,67)	^c 0,489
L3-4	Yes (n = 64)	3,27 ± 0,76	3 (1-5)		27 (6,38)	27 (7,29)	10 (3,32)
L4-5	No (n = 93)	3,32 ± 0,61	3 (2-5)	^a 0,522	33 (1,47)	43 (3,47)	17 (8,54)	^c 0,738
L4-5	Yes (n = 99)	3,34 ± 0,75	3 (1-5)		37 (9,52)	48 (7,52)	14 (2,45)
L5-S1	No (n = 95)	3,35 ± 0,66	3 (2-5)	^a 0,854	31 (3,44)	44 (4,48)	20 (5,64)	^c 0,165
L5-S1	Yes (n = 97)	3,31 ± 0,68	3 (1-5)		39 (7,55)	47 (6,51)	11 (5,35)

^aMann Whitney U Test ^cPearson Chi-Square Test.

There was a correlation between DDD and FD at all lumbar levels, with a weak correlation at the L1-2 level and a moderate correlation at other levels (r = .363-.456; P = .001; P < .01) (Table 4).

Table 4.

Assessment of correlation between DDD and FD in each level.

			Facet Degeneration
DDD		L1-2	L2-3	L3-4	L4-5	L5-S1
L1	r	0.363
L1	p	0,001**
L2	r		0.423
L2	p		0,001**
L3	r			0.451
L3	p			0,001**
L4	r				0.456
L4	p				0,001**
L5	r					0.395
L5	p					0,001**

r = Spearman’s Correlation coefficient **P < 0,01.

When the DDD, LDH, and ND groups were analyzed separately according to each level in terms of FD development, it was determined that the ND group had a significantly lower rate of FD development. There was no difference between the DDD and LDH groups (P = .005; P = .001; P < .01) (). Distribution of facet degeneration in each group are given in Figure 4. (Table 5).

Figure 4.

The non-DDD group exhibited a significantly lower incidence of FD across all levels.

Table 5

Comparison of facet joint degeneration in each level among the groups.

Joint Level	Degeneration	Group			p	Post Hoc
		DDD (n = 89)	LDP (n = 59)	Non-DDD (n = 44)		Post Hoc
		n (%)	n (%)	n (%)		DDD-LDP	DDD-N DDD	LDP-N DDD
L1-2	No	75 (3,84)	44 (6,74)	44 (0,100)	^c 0,002**	0,146	0005**	0,001**
L1-2	Yes	14 (7,15)	15 (4,25)	0 (0,0)	^c 0,002**	0,146	0005**	0,001**
L2-3	No	69 (5,77)	38 (4,64)	44 (0,100)	^c 0,001**	0,081	0001**	0,001**
L2-3	Yes	20 (5,22)	21 (6,35)	0 (0,0)	^c 0,001**	0,081	0001**	0,001**
L3-4	No	58 (2,65)	31 (5,52)	39 (6,88)	^c 0,001**	0,125	0004**	0,001**
L3-4	Yes	31 (8,34)	28 (5,47)	5 (4,11)	^c 0,001**	0,125	0004**	0,001**
L4-5	No	38 (7,42)	21 (6,35)	34 (3,77)	^c 0,001**	0,387	0001**	0,001**
L4-5	Yes	51 (3,57)	38 (4,64)	10 (7,22)	^c 0,001**	0,387	0001**	0,001**
L5-S1	No	39 (8,43)	22 (3,37)	34 (3,77)	^c 0,001**	0,429	0001**	0,001**
L5-S1	Yes	50 (2,56)	37 (7,62)	10 (7,22)	^c 0,001**	0,429	0001**	0,001**
Overall	No	32 (0,36)	16 (1,27)	32 (7,72)	^c 0,001**	0,261	0001**	0,001**
Overall	Yes	57 (0,64)	43 (9,72)	12 (3,27)	^c 0,001**	0,261	0001**	0,001**

^cPearson Chi-Square Test.

Discussion

LBP is considered a consequence of FD. Age and BMI have been reported to be related to FD.¹⁵ Several authors note the association between DDD and FD.^16,17 Our results were corresponded to these findings.

Zhu et al. found an association between LDH and FD.¹⁸ Furthermore, FD has been considered a cause of persistent pain in patients who have undergone LDH microdiscectomy surgery.⁵ In our study, we discovered a correlation between FD, DDD, and LDH at all lumbar levels.

PI and STA are considered morphologic spinopelvic parameters and remain constant after growth. The PI is fundamental to sagittal spinopelvic alignment (19). Other parameters, including LL, PLL, DLL, SS, and PT, serve as compensatory variables in the pursuit of optimal spinopelvic congruence. In numerous studies, correlations have been found between these parameters and DDD and LDH. But the effects of spinopelvic parameters on FD are not clear. Jentzsch T et al concluded that PI is correlated with LL and lower level FD.⁸ Similarly, Lv X et al reported high PI is predisposing factor for the FD in lower lumbar levels but not in upper levels.⁹ PT is associated with FD in the lumbar spine. When considering the lumbar spine in its entirety, we found only LL and PLL were related to FD. As morphologic parameters, PI and STA were not associated with it. But, upon level-specific analysis, LL and DLL were positively associated with upper level FD, while high PLL values were associated with lower level FD. PT was only associated with L4-5 FD, whereas PI was only associated with both L2-3 and L4-5 FD. The facet joints have been reported to transmit shear forces and assist the intervertebral discs in supporting approximately 16% of the vertical load (20). Roussoly et al. concluded that as distal hyperlordosis increases, a greater contact force will act on the posterior arch, and the risk of FD will increase significantly.²¹ The vectorial distribution of the increased loading associated with a high BMI is predominately shear due to the increase in LL and DLL. We think that high LL and DLL values cause the vectorial distribution of loading to be oriented in a shearing pattern instead of a compression pattern. This leads to increased loading in the posterior upper lumbar region and degeneration of the upper level lumbar FJs. Similarly, it may be hypothesized that an increase in PLL results in increased loading and degeneration of the FJs in the posterior distal lumbar region due to an increase in shear-like load distribution. Additionally, it has been demonstrated that the axial morphology of the normal distal lumbar FJs (L3 to S1) assumes a gradually more coronal orientation compared to the proximal lumbar levels, with the transverse articular dimension being greatest at the distal end. The orientation of the lumbar FJ in the sagittal plane permits a greater range of flexion and prevents rotatory instability.²² Weinberg et al found that FD was highest at the L4-5 and L5-S1 level and was correlated with a more sagittal orientation of facet joints.²³ JentzschT et al. found a relation between LL and FD through the sagittal orientation of the lower lumbar FJ, reporting that high LL is associated with sagittal FJ orientation and thus FD in the lower lumbar spine.¹⁰ These results may explain the association between high LL and FD observed in our study. Sahin et al. concluded that the prevalence of FD is positively correlated with SS, LL, and PI but negatively correlated with STA.²⁴ In our study, SS, PI, and STA are not related to FD. L4-5 had the highest rate of FD in our study, and PT was only associated with FD at this level. PT can alter the vertical direction of the load pattern to shear or compressive as a compensatory change. This could explain the association between PT and FD at L4-5, the most degenerative level in our study.

The relationship between ALL, LDH, and various spinopelvic parameters has been thoroughly studied. A strong correlation between PI and ALL has been reported.²⁵ Han Fei et al. reported that ALL tends to be at higher levels in young LDH patients.²⁶ To the best of our knowledge, there is no literature evaluating the relationship between ALL and FD. In our study, we found a significant relationship between LDH and FD, as well as a relationship between PI and FD at the L4-L5 level. However, although these associations imply that there may be a correlation between ALL and FD, we did not find a direct relationship between them. Both DDD and LDH groups have a significantly higher incidence of FD at all lumbar levels. According to Kong et al., FD is followed by disc degeneration. The correlation between DDD and FD that we found in our study is consistent with this finding.¹⁷ Sevarese et al. reported a correlation between lumbar disc degeneration and PI-LL mismatch.²⁸ Although this result suggests that a similar correlation may exist between PI-LL mismatch and FD, no such correlation was found in our investigation.

Conclusion

Age and BMI have a direct effect on the FD. However, spinopelvic parameters influence the severity of FD rather than its occurrence. In addition to the effects of lumbar lordosis as a whole, it is crucial to consider the effects of proximal and distal lumbar lordosis at the FD level separately.

Limitations

First, lifestyle, employment factors, and intrinsic muscle conditions that may affect facet degeneration cannot be evaluated in this retrospective study. Second, this study has a relatively small sample size. The duration of the study was brief, and long-term data are required to confirm the results. This is a retrospective cross-sectional study with no longitudinal information. Third, this study was conducted via radiologic images. Lee et al. discovered that the ability of existing radiologic modalities to detect facet degeneration is quite limited. They reported that 36% of histologically confirmed cases of FD were undergraded by conventional MR.²⁷ Therefore, it is possible that the extent of FD was underestimated in this study.

Availability of data and materials

The data used during the current study are available from the corresponding author on reasonable request.

Footnotes

Author Contributions

Conception and design: ZS, EB, OA.

Acquisition of data: ZS, EB, OA.

Data analysis and interpretation: ZS, EB.

Drafting and writing of the article: ZS, EB, OA.

Final Approval: ZS, EB, OA.

Declaration of Conflicting Interests

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Zafer Soydan

References

Urits

Burshtein

Sharma

, et al. Low Back Pain, a Comprehensive Review: Pathophysiology, Diagnosis, and Treatment. Curr Pain Headache Rep 2019; 23(3): 23.

Perolat

Kastler

Nicot

, et al. Facet joint syndrome: from diagnosis to interventional management. Insights Imaging 2018; 9: 773–789.

Kalichman

Kim

, et al. Facet joint osteoarthritis and low back pain in the community-based population. Spine 2008; 33(23): 2560–2565.

Manchikanti

Hirsch

Falco

Boswell

. Management of lumbar zygapophysial (facet) joint pain. World J Orthoped 2016; 7(5): 315–337.

Chen

, et al. Lumbar facet joint osteoarthritis as the underlying reason for persistent low back pain after minimally invasive discectomy. Arch Orthop Trauma Surg 2022; 10.1007/s00402-022-04595-y

Eubanks

Lee

Cassinelli

Ahn

NU.

Prevalence of lumbar facet arthrosis and its relationship to age, sex, and race: an anatomic study of cadaveric specimens. Spine 2007; 32(19): 2058–2062.

Adams

Hutton

WC.

The mechanical function of the lumbar apophyseal joints. Spine 1983; 8(3): 327–330.

Jentzsch

Geiger

Bouaicha

, et al. Increased pelvic incidence may lead to arthritis and sagittal orientation of the facet joints at the lower lumbar spine. BMC Med Imag 2013; 13: 34.

Liu

Zhou

, et al. Correlations between the feature of sagittal spinopelvic alignment and facet joint degeneration: a retrospective study. BMC Muscoskel Disord 2016; 17(1): 341.

10.

Jentzsch

Geiger

König

. Hyperlordosis is associated with facet joint pathology at the lower lumbar spine. J Spinal Disord Tech 2013 [Epub ahead of print].

11.

Chung

N-S

Jeon

C-H

Lee

H-D

Won

S-H

. Measurement of spinopelvic parameters on standing lateral lumbar radiographs: Validity and reliability. Clin Spine Surg 2017; 30: E119–E123.

12.

Tono

Hasegawa

Okamoto

, et al. Lumbar lordosis does not correlate with pelvic incidence in the cases with the lordosis apex located at L3 or above. Eur Spine J 2018; 28, 1948–1954.

13.

Weishaupt

Zanetti

Boos

Hodler

. MR imaging and CT in osteoarthritis of the lumbar facet joints. Skeletal Radiol 1999; 28(4): 215–219.

14.

Pfirrmann

Metzdorf

Zanetti

, et al. Magnetic resonance classification of lumbar intervertebral disc degeneration. Spine 2001; 26(17):1873–1878.

15.

Goode

Cleveland

George

, et al. Different Phenotypes of Osteoarthritis in the Lumbar Spine Reflected by Demographic and Clinical Characteristics: The Johnston County Osteoarthritis Project. Arthritis Care Res 2020; 72(7): 974–981.

16.

Butler

Trafimow

Andersson

McNeill

Huckman

: Discs degenerate before facets. Spine 1990; 15(2): 111–113.

17.

Kong

Morishita

, et al. Lumbar segmental mobility according to the grade of the disc, the facet joint, the muscle, and the ligament pathology by using kinetic magnetic resonance imaging. Spine 2009; 34(23): 2537–2544.

18.

Zhu

Chen

, et al. Association between lumbar disc herniation and facet joint osteoarthritis. BMC Muscoskel Disord 2020; 21(1): 56. Published 2020.

19.

Boulay

Tardieu

Hecquet

, et al. Sagittal alignment of spine and pelvis regulated by pelvic incidence: standard values and prediction of lordosis. Eur Spine J 2006; 15(4): 415–422.

20.

Kalichman

Hunter

. “Lumbar facet joint osteoarthritis: a review,” Semin Arthritis Rheum 2007; 37(2): 69–80.

21.

Roussouly

Pinheiro-Franco

. Biomechanical analysis of the spino-pelvic organization and adaptation in pathology. Eur Spine J: official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society 2011; 20(suppl 5): 609–618.

22.

Varlotta

Lefkowitz

Schweitzer

, et al. The lumbar facet joint: a review of current knowledge: part 1: anatomy, biomechanics and grading. Skeletal Radiol 2011; 40(1): 13–23.

23.

Weinberg

Liu

Xie

, et al. Increased and decreased pelvic incidence, sagittal facet joint orientations are associated with lumbar spine osteoarthritis in a large cadaveric collection. Int Orthop. 2017; 41(8): 1593–1600.

24.

Sahin

Ergün

Aslan

. The Relationship Between Osteoarthritis of the Lumbar Facet Joints and Lumbosacropelvic Morphology. Spine 2015; 40(19): E1058–E1062.

25.

Pan

Wang

Sun

. Correlation between the apex of lumbar lordosis and pelvic incidence in asymptomatic adult. Eur Spine J 2020; 29(3): 420–427.

26.

Fei

Sun

Chen

. Analysis of Spino-pelvic Sagittal Alignment in Young Chinese Patients with Lumbar Disc Herniation. Orthop Surg 2017; 9(3): 271–276.

27.

Lee

Cha

Yoo

, et al. Radiographic grading of facet degeneration, is it reliable?—a comparison of MR or CT grading with histologic grading in lumbar fusion candidates. Spine J 2012; 12(6): 507–514.

28.

Savarese

Menezes-Reis

Jorge

, et al. Sagittal balance and intervertebral disc composition in patients with low back pain. Braz J Med Biol Res 2022; 55: e12015. Published 2022 Nov 11.