Morphometric Study of Lumbar Pedicles in Delhi Region of Northern India
Author(s): Arora L, Dada R, Singh V
Vol. 3, No. 5 (2006-11 - 2006-12)
ISBN: 0973-516X
Arora L, Dada R, Singh V
Dr Latika Arora, (Assistant Professor), and Dr Vishram Singh, (Professor and HOD),
are from the Deptt of Anatomy, Santosh Medical College, Ghaziabad.
Dr Rima Dada is Associate Professor, Deptt of Anatomy, AIIMS, Delhi
Morphologic parameters of adult lumbar vertebra were studied in 25 male and 30 female vertebrae.
Horizontal and vertical diameters were measured with the help of sliding vernier caliper. Horizontal diameter
increased from L1 to L5 with the range being between 8-15 mm in male and 7-14mm in females. Observations of
vertical diameter showed an increase in measurements from LI to L5 vertebrae. The range of vertical diameter in
male vertebra was 14 to 21 mm and in female vertebrae of 14 to 19mm. The results of morphometric study of
selected human vertebrae may help to provide data for implantable devices and spinal instrumentation.
Introduction
The pedicle is the strongest part of a
vertebra, thus the vertebral pedicles are used for
placement of screws through them. A thorough
knowledge of anatomic descriptions and
dimensions of vertebra is necessary for
development of implantable devices and spinal
instrumentation. Since 1963, the routine
technique in spine fixation has been based on
‘pedicle –screw plate’. For the last 20 years
transpedicular screw implantation techniques as
a means of spinal fixation has gained
popularity1,2. Internal fixation techniques is
required for various spinal problem like spinal
fractures, gross spondylolisthesis and spinal
instabilities. For internal fixation, a screw is
inserted through the pedicle into the body of a
vertebra. With the help of screw, various devices
(rods, plates or wires) can be applied to spine for
immobilization or fixation3. For this technique to
be successful the screw should be able to
maintain purchase within the vertebral body4.
That depends on factors like availability of an
accurate screw for the pedicle size and the
quality of bone of the pedicle.
Thus, for proper implant design and
placement, detailed and accurate knowledge of
morphology of vertebrae is necessary. The exact
morphology of vertebral pedicle, its location,
size and angular alignment is difficult to
estimate by X-ray or at surgery. A mismatched
size of pedicle and screw may result in
loosening of the screw and fracture of the
pedicle, tearing of dura, leakage of CSF and
nerve-root injuries5,6).
For transpedicular screw fixation, choice of
the screw is determined by minimum diameter
of the pedicle6,7. Thus detailed study of
morphometry of pedicle is important to select
the most suitable pedicle screw.
The present study was conducted on
skeletons of Northern Indian origin to measure
the height and width of lumbar pedicles.
Material and methods
We obtained vertebral columns from the
preserved sets of bones of individual dead
bodies received at the Anatomy Department,
Santosh Medical college, Ghaziabad. 15 male
and 11 female vertebrae were studied for pedicle
morphometry. All the studied vertebrae were
ossified. The normal height and width of
pedicle was measured using Vernier calipers.
For height estimation, two close points on the
upper and lower margins of pedicles, in vertical
plane on it’s lateral aspect, were measured as
shown in Fig 1. The width was measured
between lateral and medial aspect of each
pedicle, at right angles to the long axis of the pedicle. The height and width of the vertebrae
was measured as per the methods used by I P
Singh and MK Bhasin8.
Observations
The height and width of pedicles of
male and female vertebrae, respectively, with the
mean and SD are depicted in Tables A and B,
which show that, in the both cases, the height
and width of pedicles increased from L1 to L5.
For the male vertebrae the range of height of
pedicle was 14-21 mm and that of width 8-
15mm. The respective ranges for females were
14-19mm (height) and 7-14 mm (width).
Table A: Height of Male Vertebrae
Lumbar
vertebra
Mean
mm
SD
p value
L1
14.79
70
72
L2
15.42
53
46
L3
16.42
75
23
L4
17.48
66
15
L5
19.48
48
42
Table B: Width of Male Vertebrae
Lumbar
vertebra
Mean
mm
SD
p value
L1
7.51
34
34
L2
7.95
39
93
L3
8.75
.37
1.00
L4
13.00
94
299
L5
15.34
95
361
Table C: Height of Female Vertebrae
Lumbar
vertebra
Mean
mm
SD
p value
L1
14.37
27
13
L2
15.04
30
00
L3
15.6
47
89
L4
17.11
27
76
L5
18.3
70
02
Table D: Width of Female Vertebrae
Lumbar
vertebra
Mean
mm
SD
p value
L1
7.49
37
34
L2
7.91
31
93
L3
8.71
.40
1.00
L4
12.97
97
29
L5
13.31
96
36
L5
18.3
70
02
The mean and SD were calculated for
both sides and Student’s ‘t’ test was used to
determine the difference between the right and
the left. No statistically significant difference
was observed between readings of right and left
sides.
Discussion
A detailed knowledge of the pedicle size
and dimensions is crucial for development of
implantable devices and spinal instrumentation.
Such information has numerous potential
applications. According to Pal and Routal
(1987)9 the pedicle forms maximum loaded
element of neural arch and the weight
transmission in lumbar spine is from body to
neural arch towards line of gravity.
Pedicle dimensions have been studied
by many other authors. Amonoo Kuofi (1994)3
studied horizontal and vertical diameter of
pedicles on radiographs. According to him the
width of pedicles in males and females is
maximum (14.2mm and 12.5mm respectively)
at, L5, which correlates with our study. Our
study shows that the width of pedicles in males
and females increases from L1 to L5 vertebra
with the maximum being 15.34mm in males and
13.31 mm in females of L5 vertebra. Our
findings are also supported by Singh et al
(2004)10 who measured the dimensions of
lumbar pedicles in the Saurashtra region.
According to our study the height of
lumbar pedicles also increased from L1 to L5
vertebra, maximum being 19.4mm in males and
18.3mm in females. This finding was in
conformity with that of Amonoo Kuofi3 and
Scoles, but was in contrast with findings of
Singh TC et al4 and Zindrick10.
According to Singh and co-researchers the
height of pedicles increase at L1, L2, L3 levels,
after which it decreases at L4 and L5 levels in
both sexes. The contrast with the findings of our
study could be due to racial variation. Singh et al
studied the population of a Western Indian state
(Saurashtra region in Gujarat), while we studied
that of Delhi state of North India.
The inference from our study is that the
weight-bearing and mechanical factors have
major impact on morphological and functional
adaptation of the vertebral column. Pal and
Routal (1987)9 suggested that in the lumbar
region pedicles play important role in transfer of
weight from neural arch to anterior part of the
vertebral column. Porter et al (1989) suggested
that increasing levels of physical activity were
associated with increased strength of vertebral
column in individuals aged over 18 years. The
variation in diameter of pedicles in different age
groups may be due to the weight-bearing
function.
To summarize, dimensions and angles
of pedicles change throughout the vertebral
column. Knowledge of these parameters is
important to the surgeon for using the pedicle
for screw purchase and to prevent failure of
fixation of screws.
References
- Lorenz MA, Hodges S and Vrbos LA. Spinal
fixation. Current Opinion in Orthopedics, 1993; 4:
192-204
- Zindrick MR). The role of transpedicular fixation
systems for stabilization of lumbar spine. Orthopedic
Clinics of North America, 1991; 22: 333-344
- Amonoo Kuofi HS. Age-related variations in
horizontal and vertical diameters of pedicles of
lumbar spine. J Anatomy, 1994; 186, 321-328
- Zindrick MR, Wiltse LL and Widell EH (1986)
A biomechanical study of intrapedicular screw
fixation in lumbosacral spine. Clinical Orthopedics
and Related Research; 203: 99-112
- Esses SI, Sachs BL. Complications of pedicle
screw fixation. Orthopedics
Transaction, 1992; 16: 160-161
- Weinstein SN, Rydevil BL and Rauschining W.
Anatomic and technical considerations of pedicle
screw fixation. Clinical Orthopaedics and Related
Research, 1992; 284: 34-46
- Krag MH, Beynnon MS and Pope MH et al. An
internal fixatar for posterior application to short
segments of thoracic, lumbar or lumbosacral spine -
Design and testing. Clinical Orthopaedics and
Related Research, 1986; 203: 75-98
- Singh, I P; MK Bhasin. Anthropmetry. 1968, 1rst
edition; pp 91-94
- Pal GP and Routal RV. Transmission of weight
through lower thoracic and lumbar regions of the
vertebral columns in man. Journal of Anatomy,
1987; 152: 93-105
- Singh TC, Patel MM and Gohil DV. A study of
width and height of lumbar pedicles in Saurashtra
region. J Anat Soc India, 2004; 53(1): 4-9
ISBN: 0973-516X
Arora L, Dada R, Singh V
Dr Latika Arora, (Assistant Professor), and Dr Vishram Singh, (Professor and HOD), are from the Deptt of Anatomy, Santosh Medical College, Ghaziabad. Dr Rima Dada is Associate Professor, Deptt of Anatomy, AIIMS, Delhi
Morphologic parameters of adult lumbar vertebra were studied in 25 male and 30 female vertebrae. Horizontal and vertical diameters were measured with the help of sliding vernier caliper. Horizontal diameter increased from L1 to L5 with the range being between 8-15 mm in male and 7-14mm in females. Observations of vertical diameter showed an increase in measurements from LI to L5 vertebrae. The range of vertical diameter in male vertebra was 14 to 21 mm and in female vertebrae of 14 to 19mm. The results of morphometric study of selected human vertebrae may help to provide data for implantable devices and spinal instrumentation.
Introduction
The pedicle is the strongest part of a vertebra, thus the vertebral pedicles are used for placement of screws through them. A thorough knowledge of anatomic descriptions and dimensions of vertebra is necessary for development of implantable devices and spinal instrumentation. Since 1963, the routine technique in spine fixation has been based on ‘pedicle –screw plate’. For the last 20 years transpedicular screw implantation techniques as a means of spinal fixation has gained popularity1,2. Internal fixation techniques is required for various spinal problem like spinal fractures, gross spondylolisthesis and spinal instabilities. For internal fixation, a screw is inserted through the pedicle into the body of a vertebra. With the help of screw, various devices (rods, plates or wires) can be applied to spine for immobilization or fixation3. For this technique to be successful the screw should be able to maintain purchase within the vertebral body4. That depends on factors like availability of an accurate screw for the pedicle size and the quality of bone of the pedicle.
Thus, for proper implant design and placement, detailed and accurate knowledge of morphology of vertebrae is necessary. The exact morphology of vertebral pedicle, its location, size and angular alignment is difficult to estimate by X-ray or at surgery. A mismatched size of pedicle and screw may result in loosening of the screw and fracture of the pedicle, tearing of dura, leakage of CSF and nerve-root injuries5,6).
For transpedicular screw fixation, choice of the screw is determined by minimum diameter of the pedicle6,7. Thus detailed study of morphometry of pedicle is important to select the most suitable pedicle screw. The present study was conducted on skeletons of Northern Indian origin to measure the height and width of lumbar pedicles.
Material and methods
We obtained vertebral columns from the preserved sets of bones of individual dead bodies received at the Anatomy Department, Santosh Medical college, Ghaziabad. 15 male and 11 female vertebrae were studied for pedicle morphometry. All the studied vertebrae were ossified. The normal height and width of pedicle was measured using Vernier calipers. For height estimation, two close points on the upper and lower margins of pedicles, in vertical plane on it’s lateral aspect, were measured as shown in Fig 1. The width was measured between lateral and medial aspect of each pedicle, at right angles to the long axis of the pedicle. The height and width of the vertebrae was measured as per the methods used by I P Singh and MK Bhasin8.
Observations
The height and width of pedicles of male and female vertebrae, respectively, with the mean and SD are depicted in Tables A and B, which show that, in the both cases, the height and width of pedicles increased from L1 to L5. For the male vertebrae the range of height of pedicle was 14-21 mm and that of width 8- 15mm. The respective ranges for females were 14-19mm (height) and 7-14 mm (width).
Table A: Height of Male Vertebrae
| Lumbar vertebra |
Mean mm |
SD | p value |
|---|---|---|---|
| L1 | 14.79 | 70 | 72 |
| L2 | 15.42 | 53 | 46 |
| L3 | 16.42 | 75 | 23 |
| L4 | 17.48 | 66 | 15 |
| L5 | 19.48 | 48 | 42 |
Table B: Width of Male Vertebrae
| Lumbar vertebra |
Mean mm |
SD | p value |
|---|---|---|---|
| L1 | 7.51 | 34 | 34 |
| L2 | 7.95 | 39 | 93 |
| L3 | 8.75 | .37 | 1.00 |
| L4 | 13.00 | 94 | 299 |
| L5 | 15.34 | 95 | 361 |
Table C: Height of Female Vertebrae
| Lumbar vertebra |
Mean mm |
SD | p value |
|---|---|---|---|
| L1 | 14.37 | 27 | 13 |
| L2 | 15.04 | 30 | 00 |
| L3 | 15.6 | 47 | 89 |
| L4 | 17.11 | 27 | 76 |
| L5 | 18.3 | 70 | 02 |
Table D: Width of Female Vertebrae
| Lumbar vertebra |
Mean mm |
SD | p value |
|---|---|---|---|
| L1 | 7.49 | 37 | 34 |
| L2 | 7.91 | 31 | 93 |
| L3 | 8.71 | .40 | 1.00 |
| L4 | 12.97 | 97 | 29 |
| L5 | 13.31 | 96 | 36 |
| L5 | 18.3 | 70 | 02 |
The mean and SD were calculated for both sides and Student’s ‘t’ test was used to determine the difference between the right and the left. No statistically significant difference was observed between readings of right and left sides.
Discussion
A detailed knowledge of the pedicle size and dimensions is crucial for development of implantable devices and spinal instrumentation. Such information has numerous potential applications. According to Pal and Routal (1987)9 the pedicle forms maximum loaded element of neural arch and the weight transmission in lumbar spine is from body to neural arch towards line of gravity.
Pedicle dimensions have been studied by many other authors. Amonoo Kuofi (1994)3 studied horizontal and vertical diameter of pedicles on radiographs. According to him the width of pedicles in males and females is maximum (14.2mm and 12.5mm respectively) at, L5, which correlates with our study. Our study shows that the width of pedicles in males and females increases from L1 to L5 vertebra with the maximum being 15.34mm in males and 13.31 mm in females of L5 vertebra. Our findings are also supported by Singh et al (2004)10 who measured the dimensions of lumbar pedicles in the Saurashtra region.
According to our study the height of lumbar pedicles also increased from L1 to L5 vertebra, maximum being 19.4mm in males and 18.3mm in females. This finding was in conformity with that of Amonoo Kuofi3 and Scoles, but was in contrast with findings of Singh TC et al4 and Zindrick10.
According to Singh and co-researchers the height of pedicles increase at L1, L2, L3 levels, after which it decreases at L4 and L5 levels in both sexes. The contrast with the findings of our study could be due to racial variation. Singh et al studied the population of a Western Indian state (Saurashtra region in Gujarat), while we studied that of Delhi state of North India.
The inference from our study is that the weight-bearing and mechanical factors have major impact on morphological and functional adaptation of the vertebral column. Pal and Routal (1987)9 suggested that in the lumbar region pedicles play important role in transfer of weight from neural arch to anterior part of the vertebral column. Porter et al (1989) suggested that increasing levels of physical activity were associated with increased strength of vertebral column in individuals aged over 18 years. The variation in diameter of pedicles in different age groups may be due to the weight-bearing function.
To summarize, dimensions and angles of pedicles change throughout the vertebral column. Knowledge of these parameters is important to the surgeon for using the pedicle for screw purchase and to prevent failure of fixation of screws.
References
- Lorenz MA, Hodges S and Vrbos LA. Spinal fixation. Current Opinion in Orthopedics, 1993; 4: 192-204
- Zindrick MR). The role of transpedicular fixation systems for stabilization of lumbar spine. Orthopedic Clinics of North America, 1991; 22: 333-344
- Amonoo Kuofi HS. Age-related variations in horizontal and vertical diameters of pedicles of lumbar spine. J Anatomy, 1994; 186, 321-328
- Zindrick MR, Wiltse LL and Widell EH (1986) A biomechanical study of intrapedicular screw fixation in lumbosacral spine. Clinical Orthopedics and Related Research; 203: 99-112
- Esses SI, Sachs BL. Complications of pedicle screw fixation. Orthopedics Transaction, 1992; 16: 160-161
- Weinstein SN, Rydevil BL and Rauschining W. Anatomic and technical considerations of pedicle screw fixation. Clinical Orthopaedics and Related Research, 1992; 284: 34-46
- Krag MH, Beynnon MS and Pope MH et al. An internal fixatar for posterior application to short segments of thoracic, lumbar or lumbosacral spine - Design and testing. Clinical Orthopaedics and Related Research, 1986; 203: 75-98
- Singh, I P; MK Bhasin. Anthropmetry. 1968, 1rst edition; pp 91-94
- Pal GP and Routal RV. Transmission of weight through lower thoracic and lumbar regions of the vertebral columns in man. Journal of Anatomy, 1987; 152: 93-105
- Singh TC, Patel MM and Gohil DV. A study of width and height of lumbar pedicles in Saurashtra region. J Anat Soc India, 2004; 53(1): 4-9