|Year : 2020 | Volume
| Issue : 2 | Page : 79-82
Lumbar facet joint morphometry in the southeast asian population: A cadaveric study
Vishal Kumar1, Rohit Kansal1, Ashish Dagar1, Parmod Singh2, Chiman Kumari2, Sarvdeep Singh Dhatt1
1 Department of Orthopaedics, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
2 Department of Anatomy, Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
|Date of Submission||11-Feb-2020|
|Date of Acceptance||21-Mar-2020|
|Date of Web Publication||10-Sep-2020|
Department of Orthopaedics, PGIMER, Chandigarh - 160 012, India
Source of Support: None, Conflict of Interest: None
Objectives: Facet joint morphometry may vary among different ethnic groups. The purpose of this cadaveric study is to delineate the lumbar facet joint morphometry in the Southeast Asian population through direct measurement techniques. Methodology: A prospective study was conducted at PGIMER, Chandīgarh in 2019. In five cadavers, facet joints from L1-L2 to L5-S1 on either side were carefully exposed. With mutual consensus, two senior authors expose and demarcate the facet joint boundaries, and supero-inferior and transverse diameter of the facet joints (total fifty facet joints) were recorded using compass and ruler technique. Results: The mean age was 80.2 ± 7.3 years. The mean transverse and supero-inferior diameter were lowest at L4-L5 (1.08 cm and 1.18 cm, respectively), and maximum at L5-S1 (1.24 and 1.32 cm, respectively). No statistically significant change in both transverse and supero-inferior facet joint diameter was noted from L1 to S1 (P = 0.063 and 0.256, respectively). The supero-inferior diameter of the facet joints on either side was persistently noted to be greater than the transverse diameter at all levels. Further, no significant difference was noted in both diameters on the comparison, on either side from L1 to S1. Conclusion: Cadaveric studies in indexed journals regarding lumbar facet morphometry, particularly in the Southeast Asian population are scarce. The current study has measured the facet joint as a whole from L1 to S1, rather than superior and inferior articular facets separately and these data are more valid, cautionary and clinically useful for spine surgeon while considering trans facet fusion particularly in this subset of the population.
Keywords: Asian continental ancestry group, cadaver, lumbosacral region, population, zygapophyseal joint
|How to cite this article:|
Kumar V, Kansal R, Dagar A, Singh P, Kumari C, Dhatt SS. Lumbar facet joint morphometry in the southeast asian population: A cadaveric study. J Orthop Dis Traumatol 2020;3:79-82
|How to cite this URL:|
Kumar V, Kansal R, Dagar A, Singh P, Kumari C, Dhatt SS. Lumbar facet joint morphometry in the southeast asian population: A cadaveric study. J Orthop Dis Traumatol [serial online] 2020 [cited 2020 Oct 30];3:79-82. Available from: https://www.jodt.org/text.asp?2020/3/2/79/294741
| Introduction|| |
Facet joints or zygapophyseal joints are the synovial joints that play an important role in spine kinematics and load transfer.,, These joints provide stability to the posterior column of the spine and restrict excessive rotational, shearing, and flexion forces. These joints bear approximately 35% of static and 33% of dynamic compression load of the spine., Like other weight-bearing joints, repeated cycles of loading and/or abnormal orientation of the facet joint (facet tropism) may lead to excessive wear and tear of facet joints and thereby, predispose for low backache, early degenerative arthritis, prolapsed intervertebral disc, and spondylolisthesis.,,, Transfacetal fusion alone or as a part of posterolateral fusion is a well-known modality of the treatment. Knowing the measurement of facet joint increase, the precision of surgery. Different literature, so far, has been published that enlighten us with various modalities including direct measurement of facet joints either on a cadaver or freeze-dried vertebrae to radiological measurement with ultrasonography, computed tomography (CT), or magnetic resonance imaging.,,, To date, no indexed literature could be traced describing direct facet joint measurements in cadavers in the southeast Asian population.
| Methodology|| |
A prospective study was conducted at Postgraduate Institute of Medical Education and Research (PGIMER), Chandigarh, a premier tertiary care and research center in North India. Five cadavers were included in the study. Cadavers of those patients with a history of traumatic spine injuries such as fracture-dislocation or listhesis or other significant spine pathologies such as tumor, infection, or pott spine were excluded. Skin dissection and exposure of the facet joints in all five cadavers were done by two surgeons in the anatomy dissection hall of the institute. Clear demarcation of facet joint boundaries was done on either side. With compass and ruler technique, the transverse and supero-inferior diameters of each facet joint on either side from L1 to S1 (fifty facet joints in total) were noted after the mutual consensus of all authors [Figure 1]a and b].
|Figure 1: (a) Picture showing the exposure of the right L2–L3 facet joint with clear identification of borders. (b) Picture showing measurement of diameter with the help of a compass and the ruler|
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A detailed thorough extensive and exhaustive research was done on PubMed, Cochrane, and Embase database but no relevant English or Anglophonic literature could be traced that have studied facet joint morphology in cadavers, particularly in this subset of the population [Table 1].
The data obtained were analyzed using appropriate statistical tests. All discrete categorical data were represented in the form of either a number or percentage, whereas the continuous data, which was normally distributed, was written in the form of its mean and standard deviation. The normality of quantitative data was checked using measures of Kolmogorov–Smirnov tests of normality. The Mann–Whitney test was employed when two groups of skewed data were under consideration. In the case of normally distributed data, the means of two groups were compared using an independent t-test. Proportions were compared using either the Chi-square test or Fisher's exact test, depending on their applicability. McNemar test was applied for comparison between the categorical values of different groups. Whereas, the Wilcoxon signed-rank test was used for categorical data.
All the statistical tests were two-sided and were performed at a statistical significance level of α = 0.05. The statistical analysis was performed using IBM SPSS Statistics (version 22.0) IBM corporation, United States.
| Results|| |
The mean age of cadaver used in the study was 80.2 ± 7.3 years, including a female cadaver [Table 2]. The mean superior-inferior diameter of the facet joint was lowest at L4-L5 (1.18cm), whereas it was maximum at L5-S1 (1.32cm). Similarly, the mean transverse diameter was lowest at L4-L5 (1.08cm), whereas it was maximum at L5-S1 (1.24cm), respectively. No statistically significant change in both transverse and supero-inferior facet joint diameter was noted from L1 to S1 with a P = 0.063 and 0.256, respectively [Table 3].
On pairwise comparison, the supero-inferior diameter of facet joints on either side was persistently noted to be greater than the transverse diameter at all levels [Figure 2]a and [Figure 2]b. Further, the application of the Levene's test for equality of variances and t-test for equality of means showed no statistically significant difference (P > 0.05) in both transverse and supero-inferior diameters on comparison on either side from L1 to S1 [Table 4] and [Figure 3].
|Figure 2: (a) Trend of supero-inferior and transverse diameter in the right joints. (b) Trend of supero-inferior and transverse diameter in the left facet joints|
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| Discussion|| |
With the better understanding of spine kinematics, normal and pathological anatomy and the advances in surgical techniques and spine instrumentation, the concepts and management of various spine pathology have seen a recent revolution. The facet joint has now been considered to play a pivotal role in the spine motion segment and has been found to be at the root of various spine pathology.,,,,, Facet joint arthrosis has been identified as one of the major causes of chronic low backache. Various studies have shown the association of facet atropism with degenerative spondylolisthesis and disc prolapse.,,,, Further, the indications of facet fusion have remarkably increased and different techniques have evolved for trans facet fusion to provide stability to the spine motion segment, as in case of low-grade degenerative spondylolisthesis, or as part of the posterolateral fusion of the spine. The variable literature has suggested benefits of simple surgical technique, comparable high fusion rates and lesser complications with transfacet fusion as compared to transpedicle fusion.,,
The spine surgeon should be well versed with the morphometry of the lumbar facet joint and its possible variations in different ethnic groups, to achieve the best surgical outcome. To date, even on extensive PubMed, Cochrane, and Embase search, no cadaveric study could be traced that have studied the lumbar facet joint morphometry in this ethnic group [Table 1]. Mohanty et al. in 2017, had published a study regarding the morphometric evaluation of lumbar facets in the South Indian population, but it was not a cadaveric study, rather CT scan as a screening modality was used. In the present study, fifty facet joints from five cadavers were thoroughly evaluated. The study group included in other studies were relatively younger, unlike our study where the mean age was 80 years.,,
In the current study, the increase in facet joint dimensions was noted from L1 to L3, though it further decreased at L4–L5 level and then again increased at L5–S1 level. The L5–S1 facet had the maximum dimensions whereas the L4–L5 had the lowest of all. Further, the differences in facet joint dimensions on either side were not significant. This is in contrary to previous studies which have reported an increase in diameter of the articular facet from L1 to S1.,,, The measured values by the compass and ruler technique in this cohort study were mutually agreed on by two senior authors.
Most of the previously published data are based on the Western population and have mostly used human dried vertebra for direct measurement, thereby ending up violating the soft tissue attachments-like capsule around the joint. Further, these studies have measured superior and inferior articular facet separately.,,, On the other hand, the current study has attempted to delineate the facet joint dimensions in cadaver, particularly of the Southeast Asian origin and has measured facet joint as a whole. The proposed advantage of this study is that it has not violated the capsule of the facet joint and has included even the joint space between the superior and inferior articular facet, thereby giving more accurate and clinically feasible parameters for facet joint fusion. Fluctuations and contradictions with previously reported literature on the trends of the facet joint and measurement from L1–L2 down to L5–S1 further adds to the merit of this study, thereby cautioning the surgeon about taking into consideration the valuable variable ethnic factors in the measurements and surgery thereafter.
| Conclusion|| |
The global rise in the popularity of transfacet fusion has made it important for spine surgeons to be well versed with dimensions of the facet joint. Such data on the southeast Asian population on the cadaveric study are lacking in standard and indexed literature. The current study has measured the facet joint as a whole from L1 to S1, rather than superior and inferior articular facets separately and these data are more valid, cautionary and clinically useful for spine surgeons while considering trans facet fusion particularly in this subset of the population.
This is of vital importance that spine surgeons should understand that the same size does not fit all. It simply dictates the surgeon to consider the racial and regional variations into consideration while doing fusion surgeries. Due to the paucity of literature in the southeast Asian population, most of the surgeons rely on the Western published database. This may lead to an inappropriate selection of screws, leading to inadvertent complications intraoperatively.
We would like to extend our gratitude to the Department of Anatomy, PGIMER, Chandigarh, for hand on hand cooperation and support.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2], [Table 3], [Table 4]