View of Lumbar Disc Measurements in Egyptians

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Lumbar Disc Measurements in Egyptians

Eman S. El-Shetry¹, Nahed Elwan², Heba A E Mohamed³, Mohamed Ezzat⁴ and Amal Al- Shahat Ibrahim⁵

1Eman SaadElsayedElshetry: Assistant professor of Human Anatomy & Embryology zagazig university, Egypt. Email: [email protected] phone:01271383790

2Nahed Mohamed Mostafa Elwan: demonstrator of Human Anatomy & Embryology zagazig university, Egypt. Email: [email protected] phone: 01140501128

3Heba AbdelmoneimElsayed Mohamed: assistant professor of radiology, zagazig university, Egypt. Email:[email protected] phone: 01065809804

4Mohammad Ezzat Elsayed Ezzat: lecturer of neurosurgery department zagazig university, Egypt. Email: Dr_ [email protected]

5Amal Alshahat Ibrahim Alshahat: professor of Human Anatomy & Embryology zagazig university, Egypt. Email: [email protected] phone: 01282128784

Corresponding author:

EmanSaadElsayedElshetry:Assistant professor in Human Anatomy & Embryology department, zagazig university, Egypt. Email :[email protected] phone: 01271383790

Abstract

Background: lumbar disc pathology is a common issue. The vertebral bodies are joined together with secondary cartilaginous joints developed for weight-bearing and stress movements.

Intervertebral disc degeneration is an aging process affecting large portion of the adult population. Because it is sometimes asymptomatic, it is so difficult to study its epidemiology, so magnetic resonanceimaging (MRI) is the initial imaging technique used for the evaluation of most spinal disorders including degenerative disc diseases.

Objectives: The aim is to study normal variations in dimensions oflumbar intervertebral discs at L3-L4, L4- L5&L5-S1 levels in relation to age and sex to give basis for Egyptian measurements.

Patients and methods: The total number of the studied individuals was120 healthy individuals of both sexes with normal MRI, including 57 males and63 females aged from 18 years to 48 years. High field (1.5) Tesla magnetic resonance imaging system Philips (Achieva class II USA) was used to get magnetic resonance images of this work at radiology units of Zagazig University Hospitals., in the period from April, 2017 to December, 2019. Cases of the study were divided into two age groupsGroup (A):include 90 persons whom ages ranged between18-40 years old.Group (B):include 30 persons whom ages ranged from above 40to 48 years old.

Results:Disc measurements showed different relation to sex according to the level and some of thesemeasurements increased with age especially al L3-L4 and L4-L5 levels but not at L5-S1 level.

Conclusion:Determining the dimensions of lumbar intervertebral discs for establishment of Egyptian measurements using MRIis of agreat value with the intervertebral inter-body fusion and artificial disc replacement.

Key words: Lumbar intervertebral disc, Magnetic Resonance Imaging,lumbar spine, lumbar intervertebral disc measurement.

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Introduction:The intervertebral disc (IVD) composition is established to withstand great stresses through the liquid and elastic characteristics of nucleus pulposus and annulus fibrosus acting together. The nucleus is gradually destroyed by compression forcesbut itis incompressible.

It acts to receive primarily vertical forces from the vertebral bodies and redistribute them in horizontal plane (1). Low back pain (LBP) is also known as lumbago, is extremely prevalent, and is considered the second most common reason for people to seek medical consultation. LBP accounts for about 15% of all sick leaves from work(2). Magnetic Resonance Imaging (MRI) is the initial imaging technique used for the evaluation of most spinal disorders, including degenerative disc and bone disease(3).(4) expected that that disc measures would be helpful for surgical reconstruction for treatment of many lumbar spine diseases as they could predict the appropriate size of the devices inserted in the intervertebral space. Reduced disc height is a primary indicator of degenerative intervertebral disc pathology (5)and (6) and it can help in screening patients being considered for total disc replacement (TDR) surgery or fusion (6).

Previously, discectomy combined with fusion was the main modality of treatment to treat symptomatic lumber degenerative disc disease but in the last few years some articles have focused on the issue that fusion might accelerate degeneration of adjacent disc levels so that disc prosthesis have been designed to provide normal motion and to protect adjacent discs (7).

Methods:The total number of the studied individuals was120 healthyindividuals of both sexes who had normal MRI, including 57 males and63 females aged from 18 years to 48 years.

This work had been carried outat the radiology unit, ZagazigUniversity Hospitals, Faculty of medicine, in the period from April,2017 to December, 2019.All patients were subjected to magnetic resonance imaging (MRI). Eventually, any positive criterion indicating a neurological pathology from the history taken or upon viewing the subjects' MRI was an indicator to exclude this subject from the study protocol.

Study design: cross sectional descriptive study.Inclusion criteria: include age from 18– 48 years old, no history of lumber spine operation and no history of lumber spine trauma.Exclusion criteria: Any abnormalities detected clinically or by magnetic resonanceimaging (congenital anomalies of the spine, inflammatorydiseases, tumors ,spine fractures..etc.) history of lumber spine trauma or operation andextremes of height(e.g. gigantism, dwarfism…etc.)

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Method of measurements of the lower three lumbar intervertebraldiscs described in table1:

Anterior Height (AH)is the distance between the most anteriorpointsofthe upper and lower borders ofvertebrae located at the intervertebral disc level.Middle Height (MH)is thedistance between the midpoint of the lower border of the vertebra above and themidpoint of upper border of the vertebra below.Posterior Height (PH) is the distance between the most posterior pointsof the upper and lower borders of vertebrae located at the intervertebral disc level. Anterior- Posterior Diameter (APD)is the distance between the midway of AH and the midway of PH of intervertebral disc space. Transversediameter (TD) isthe distance between the most lateral points of the disc on one side to the most lateral point of the lumbar intervertebral disc on the other side.

Data analysis

• The data were coded, entered and processed on computer using Statistical package for social science (SPSS) (version 24).The results were represented in tabular and diagrammatic forms then interpreted. Mean, standard deviation, range, frequency, and percentage were use as descriptive statistics. The following test was done:

Chi-Square testΧ² was used to test the association variables for categorical data.

Student's t-test was used to assess the statistical significance of the difference between two population means in a study involving independent samples. P value was considered significant as the following:

* P > 0.05: Non significant

* P ≤0.05: Significant

Results: Difference between male and female regarding intervertebral disc measurements changed according to the level as showed in table 2(fig.1&3): At level of L3-L4 Disc: AH, MH, PH, TD and APD(all dimensions)were increased among males than females (p ≤ 0.05), regarding to L4-L5 Disc:There was no statistically significant difference between male and female regarding PH (p >0.05), while AH, MH, TD and APD increased among males than females (fig.10&12). Regarding toL5-S1 disc: There was no statistically significant difference between both sexes regarding AH,MH and PHwhile TD and APD increased among males than females (fig.2&4).Patients were divided into two age groups as described in table 3to find the correlation of measurements with age and the results were (fig.5, 6, 7&8).

Regarding to L3-L4 Disc: there was no statistically significant difference between the two age groupsregarding AH, while there was statistically significant decrease in MH, PH, T D and

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APD among group A than group B. Regarding to L4-L5 Disc(fig.9, 10, 11&12): There was no statistically significant difference between two groups regarding MH , while there was statistically significant decrease in AH, PH, T D and APD among group A thangroup B.Regarding to L5-S1 Disc: there was no statistically significant difference between two groups regarding AH,PH, TD and APD , while MH increased among subjects of group A than group B.We can conclude from these results that most ofdisc measurements increased in males especially al L3-L4 and L4-L5 levels and these measurements may increasewith age especially at L3-L4 and L4-L5levels also but not at L5-S1 level that showed no difference between age groups in disc measurements except MH.

Table1: Measurements of different dimensions of the lower three lumbar intervertebral disc levels

Rang Mean ± SD

L3-L4 Disc AH 1.05 - 1.78 1.31 ± 0.19

MH 1.06 - 1.66 1.29 ± 0.17

PH 0.82 -1.32 1.02 ± 0.149

TD 3.93 - 5.79 4.78 ± 0.53

APH 2.71 - 3.78 3.27 ± 0.34

L4-L5 Disc AH 1.10 - 2.30 1.56 ± 0.25

MH 1.06 -1.65 1.40 ± 0.15

PH 0.29 - 1.44 0.99 ± 0.23

TD 0.29 - 1.44 4.84 ± 0.42

APD 2.67 - 4.03 3.36 ± 0.37

L5-S1 Disc AH 0.64 - 2.18 1.475 ± 0.41

MH 0.55 - 1.73 1.25 ± 0.29

PH 0.49 - 1.18 0.78 ±0.18

T D 3.97 - 5.62 4.59 ± 0.41

APD 2.63 - 3.84 3.19 ±0.26

Table2.Comparison between male and female regarding different disc dimensions

male female t. test P.

value

L3-L4 D

AH Mean ± SD 1.39 ± 0.21 1.24 ± 0.14 4.722 0.000 MH Mean ± SD 1.39 ± 0.17 1.20 ± 0.11 7.474 0.000 PH Mean ± SD 1.05 ± 0.13 0.99 ± 0.16 2.180 0.031

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TD Mean ± SD 5.20 ± 0.37 4.39 ± 0.31 13.076 0.000 APD Mean ± SD 3.55 ± 0.14 3.01 ± 0.25 13.973 0.000

L4-L5 Disc

AH Mean ± SD 1.66 ± 0.28 1.47 ± 0.17 4.458 0.000 MH Mean ± SD 1.44 ± 0.17 1.36 ± 0.11 2.756 0.007 PH Mean ± SD 0.97 ± 0.28 1.00 ± 0.17 0.804 0.423 TD Mean ± SD 5.19 ± 0.20 4.51 ± 0.28 15.012 0.000 APD Mean ± SD 3.64 ± 0.23 3.11 ± 0.28 11.000 0.000

L5-S1 Disc

AH Mean ± SD 1.54± 0.48 1.42 ± 0.33 1.612 0.110 MH Mean ± SD 1.28 ± 0.34 1.22 ± 0.24 1.128 0.262 PH Mean ± SD 0.76 ± 0.18 0.81 ± 0.17 1.548 0.124 T D Mean ± SD 4.88 ± 0.38 4.33 ± 0.23 9.807 0.000 APD Mean ± SD 3.30 ± 0.19 3.08 ± 0.26 5.049 0.000

Figure 1: Anterior, middle & posterior disc height of lower three lumbardiscs of 24 years female.

Figure2: Anterior, middle & posterior disc height of lower three lumbar discs of 47 years female.

Table3:Comparison between age group A and age group B regarding different disc dimensions.

Group A Group B t. test P.

value L3-L4

Disc

AH Mean ± SD

1.31 ± 0.18 1.32 ± 0.22 0.181 0.857

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SD

1.23 ± 0.12 1.49 ± 0.149 9.396 0.000 PH Mean ±

SD

0.98 ± 0.15 1.12 ± 0.12 4.376 0.000

TD Mean ± SD

4.67 ±0.53 5.09 ± 0.36 3.944 0.000

APH Mean ± SD

3.18 ± 0.35 3.52 ± 0.01 5.345 0.000

L4-L5 Disc

AH Mean ± SD

1.53 ± 0.18 1.65 ± 0.38 2.143 0.034

MH Mean ± SD

1.39 ± 0.11 1.44 ± 0.23 1.783 0.077

PH Mean ± SD

0.96 ± 0.25 1.06 ± 0.14 2.202 0.030

TD Mean ± SD

4.75 ± 0.45 5.10 ± 0.17 4.189 0.000

APD Mean ± SD

3.29 ± 0.39 3.58 ± 0.12 3.914 0.000

L5-S1 Disc

AH Mean ± SD

1.45 ± 0.40 1.54 ± 0.42 1.067 0.288

MH Mean ± SD

1.19 ± 0.27 1.43 ± 0.27 4.078 0.000

PH Mean ± SD

0.77 ± 0.19 0.82 ± 0.13 1.342 0.182

T D Mean ± SD

4.59 ± 0.46 4.61 ± 0.22 0.220 0.826

APD Mean ± SD

3.17 ± 0.29 3.24 ± 0.02 1.173 0.243

Figure3:Anterior, middle & posterior disc height of lower three lumbardiscs of 36 years male

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Figure4: Anterior, middle & posterior disc height of lower three lumbardiscs of48 years male.

Figure 5: Antero posterior diameter of lower three lumbar IVDs in 33 years male.

Figure 6: Antero posterior diameter of lower three lumbar IVDs in42 years male.

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Figure 7: Antero posterior diameter of lower three lumbar IVDs in22 years female.

Figure 8: Antero posterior diameter of lower three lumbar IVDs in43 years female.

Figure 9: Transverse diameter of L4-L5 disc in 30 years male.

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Figure 10

:

Transverse diameter of L4-L5 disc in 42 years male.

Figure 11: Transverse diameter of L4-L5 disc in 22 years female.

Figure12: Transverse diameter of L4-L5 disc in 43 years female.

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Discussion:In the present study, the use of MRI hadallowed detailed clear measurements to different dimensions of lumbardiscs at the last three lumber levels (8).It wasfound the MRI is excellent diagnostic method used in the studyof age changes in lumbar region.The used method was in agree with (9)who stated that MRI provides a clear representation of the anatomy of the disc and disco-vertebral complex, information that will allow accurate diagnosis of degenerative disc disease.The present study was conducted on 120 healthy individuals of both sexes who had normal lumbar MRI. On the otherhand(10)measured the dimensions of intervertebral discs using traditional cadaveric methods.Age range of the studied cases was (18-48) years and the mean of age (32.95 ± 7.64). The number of cases between 18-40years was 90 while cases above 40 to48 were 30 cases.These results showed in table 3 correlate with (11)who studied the midsagittal dimensions of intervertebral discs in different age groups in bothsexes using MRI images of lumbar spine for normal Egyptianpopulation with ages ranged from 20 to 50 years old. He showed thatanterior height at L3-L4and L4-L5 was increasedwith age nearly in all decades studied but not at L5-S1 level that wasdecreased with age.As regards to measurements of the present study at L4-L5 disc in table 1, theresultswere in agree with (12)who studied anterior andposterior lumbar intervertebral disc measurements and revealed that alsoL4-L5 disc has the greatest value before decline in L5-S1 disc level.

The present results are totally in agree with (13, 14 and 15)whofound that the heights of L3- L4 and L4-L5disc levels increase in olderage groups. (16)reported also that the L4-L5 disc isthe largest intervertebral disc of human body and this is probably due tothe increased mobility at that level of spine.

On the other hand (17and 18) found that the height ofL5-S1 disc was quite variable in some subjects it was small, however inothers it was the largest one. Regarding to disc measurements in relation to the sex of subjects,the present study revealed that, At the level L3-L4 disc there was anincrease in all dimensions (AH, MH, PH, T D and APD) in males thanfemales. At level of L4- L5 disc There was no difference between malesand females regarding its (PH) while there was an increase in (AH, MH,TD and APD) between males than females. At level of L5-S1 disc therewas no difference between males and females (AH, MH and PH) butthere was increase in its (TD and APD) between males than females.These results were coincided with (17, 19, 20,and

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21)who found that the mean of discheights were larger in males than females at all levels.

(22)reported that South African males were significantlygreater than females in most of lumbar intervertebral discmeasurements.On the other hand (11) reported that males differed fromfemales in MH with alternatingincrease and decrease at most of disclevels while in females it showed steady increase with age. There wasgradient increase from L3-L4 toL4-L5 discs in all disc measurementsfollowed by decrease in L5-LS1in both male and female in all agegroups which were in agree with our results.L5-S1 disc measurements were added to the levels that increasefrom above downwards in some studies as mentioned by (23and 24).

Conclusion:Application of this study which was carried out to measure differentdimensions of thelast three lumbar intervertebral discs to act as a data base for establishment ofEgyptian measurements using Magnetic Resonance Imaging which will be of agreat value with the instruments for intervertebral interbody fusion andartificial disc replacement.It enables the medical engineers to manufacturedisc prosthesis according to normal measurements of Egyptian population.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

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