The document discusses the anatomy and surgical treatment of the spine. It describes the typical divisions of the spinal column, common curves seen, vertebral anatomy including facets and ligaments, and pedicle anatomy. Surgical techniques like pedicle screw fixation are covered including entry points, trajectories, and complications. Degenerative spinal conditions and their treatment with options like bracing, decompression surgery, and stabilization are also summarized.

2. Anatomiya • Columna spinalis-in 5 bölümü
var:
• Cerical – 7 vertebra;
• Thoracic – 12 vertebra;
• Lumbar – 5 vertebra
• Sacrum – 5 vertebra
• Coccyx – 3-4 vertebra

3. Anatomia Curves
• Kifoz – 1. cervical
2. lumbar
Lordoz – 1. thorakal
2.sacral

4. Typical Vertebrae

5. Typical Vertebrae

6. Vertebral Relationships

8. Major Ligaments of the Spine
• Anterior
Longitudinal
Ligament - ALL
• Atlanto-Occipital
Membrane
• Posterior Longitudinal
Ligament
• Supraspinous
• Interspinous
• Ligamentum Flavum
• Intertransverse

9. Special Joints of Spine
• Lumbo-Sacral
• Atlanto-Axial Joint

10. Lumbar Facets
• Facet Joints (Typical)
• Superior articular facets of one
vertebrae with inferior facets
of vertebrae above
• Synovial gliding joints
• Surrounded by joint capsule
and small capsular ligaments
• The type and amount of
motion in any given part of the
spine is dictated by the
orientation of the articular
facets as well as the fluidity,
elasticity and thickness of the
intervertebral discs

11. Pedicle
1. Pedicle: strong, cylindrical, anatomic bridge between the dorsal spinal elements
and the vertebral body; consists of a strong shell of cortical bone and a core of
cancellous bone.
2. Tranverse pedicle angle or coronal angulation (Figure 1B) decreases as one
descends caudally in the spine until the lumbar region. The angle increases as the
lumbar spine is descended.
3. Sagittal pedicle angle (Figure 1C) is steep throughout the midthoracic spine and
in the upper lumbar spine.
4. Intrathecal nerve roots course along the medial aspect of the pedicle. At T12,
the dural sac is 0.2 to 0.3 mm away from the pedicle. Below L1, the medial side of
the pedicle is almost touching the cauda equina. Nerve root occupies the ventral
and rostral one-third of the foramen. Thus, violation of medial or caudal cortex of
the pedicle risks injury to the nerve root.

12. Deformative spinal diseases
• Scoliosis
• Kyfosis
• Lordosis
• Osteogenesis imperfecta

13. Treatment
• Observation
• Bracing
• Surgery
• Posterior approach
• Anterior approach
• Decompressive laminectomy
• Minimally invasive surgery (MIS)

14. Surgical Treatment - Stabilisation
Advantages of Pedicle Screw Fixation:
1. Can rigidly stabilize both the ventral and dorsal aspects
2. The pedicle also represents the strongest point of attachment of the spine and thus
significant forces can be applied to the spine without failure of the bone-metal
junction.
3. The rigidity of pedicle fixation allows for the incorporation of fewer normal
motion segments in order to achieve stabilization of an abnormal level.
4. Can be used after a laminectomy or traumatic disruption of laminae, spinous
processes and/or facets.
5. Additional advantages include less requirements for postoperative bracing and
improvements in fusion rates.

15. Surgical Treatment - Stabilisation
Disadvantages of Pedicle Screw Fixation:
1. Steep learning curve.
2. Caudal or medial penetration of the pedicle cortex can result in dural or neural
injury.
3. Implantation of pedicle screws requires extensive tissue dissection to expose the
entry points and to provide the required lateral to medial orientation for optimal
screw trajectory.
4. Lengthy operative time with potential for significant blood loss and increased risk
of infection.
5. Postoperative imaging studies (especially MRI) are, in part, obscured by the
implants.
6. Rigid fixation can accelerate adjacent motion segment degeneration.
7. Costly procedures.

16. Surgical Treatment - Stabilisation
Principal Indications for Pedicle Fixation:
1. Existing painful spinal instability:
* post-laminectomy spondylolisthesis
* painful pseudoarthrosis
2. Potential instability:
* spinal stenosis
* degenerative scoliosis
3. Unstable fractures.
4. Augmenting anterior strut grafting:
* tumor
* infection
5. Stabilizing spinal osteotomies.

17. Surgical Treatment - Stabilisation
Contraindications for Pedicle
Fixation:
1. Recent infection.
2. Laminectomies that will not
cause instability
3. Fusions which are normally
successful without fixation.

18. Pedicle Screw Entry Sites and
Trajectory
General Remarks:
1. Preoperative planning using plain radiographs and CT scan is important in deciding
the bone quality, pedicle transverse diameter and screw trajectory.
2. Sagittal pedicle angle increases in the thoracic spine from an average of 0 degs at
T1 to 10 degs at T8 and then decreases to 0 degs at T12.
3. Usually the L4 sagittal pedicle angle is 0 degs and subsequent rostral and caudal
levels are associated with progressively greater sagittal angles.
4. Lordotic curve of the lumbar spine produces a rostral angulation for upper lumbar
screws.
5. L5 pedicle screw is 5 degs to 10 degs caudally inclined.
6. Coronal plane angulation (how medial?) at T1 is 10 degs to 15 degs and at T12 is 5
degs.
7. At L1 the medial angulation of 5 degs to 10 degs is satisfactory.
* a wider angle in the coronal plane is necessary to avoid lateral penetration of the
pedicle in
the lower lumbar spine.
* the coronal plane angle increases approximately 5 degs per level from L1 to the
sacrum

19. Pedicle Screw Entry Sites and
Trajectory
Schematic diagram showing that the
coronal (medial) angle increase
approximately 5 degs per level from L1 to
the sacrum.

20. Pedicle Screw Entry Sites and
Trajectory
Thoracic Spine:
In the thoracic spine, transverse process commonly does not align with the
pedicle in the axial plane. Thus, the anatomic landmarks that are used for
lumbar pedicle screw insertion cannot be reliably used in the thoracic spine.
The transverse process is rostral to the pedicle in the upper thoracic spine and
caudal to the pedicle in the lower thoracic spine (crossover occurs at T6-7).
Because of this variability, fluoroscopic guidance or direct vision and palpation
of the pedicle via a laminotomy is highly recommended for insertion of
thoracic pedicle screws. At T1-3, 4.5 mm diameter screws that are 25-30 mm
in length are usually recommended. At T4-T10, screws are usually 4.5 mm in
diameter and 30-35 mm in length.

21. Pedicle Screw Entry Sites and
Trajectory
Lumbar Spine:
Conventional entry site for pedicle screw placement in the lumbar spine is at the
junction of
the lateral facet and the transverse process (Figure 4A) or bisection of a vertical line
through the facet joints and a horizontal line through the transverse process

22. Pedicle Screw Entry Sites and
Trajectory
Nuances in pedicle screw insertion in lumbar spine:
1. Although the midline of the transverse process corresponds to the location of the
pedicle at L4, this relationship does vary at different lumbar levels. Above L4, the
midline of the transverse process is rostral to the pedicle. At L5, it is an average of 1.5
mm caudal to the pedicles.
2. Muscle dissection is performed as lateral as possible to allow palpation of the
transverse process. You have to be persistent and patient- have some good retractors.
3. Lateral aspect of the pedicles is palpated with a nerve hook over the transverse
process.
4. Small laminotomy may be performed (if no decompression is being performed) to
palpate the medial aspect of the pedicle and its rostral/ caudal borders.
5. Palpation of the pedicle helps to guide accurate placement of the screw into the
pedicle.
6. Some of the superior facet at the transverse process has to be decorticated for a
good entry site of the screw.

23. Pedicle Screw Entry Sites and
Trajectory
Step 1: Entry site is decorticated using a burr and a high-speed drill or a rongeur.
Step 2: Burr or awl is used to penetrate the dorsal cortex of the pedicle.
Step 3: Curved or straight pedicle probe is used to develop a path for the screw through
the cancellous bone of the pedicle into the vertebral body.
* advancement of the probe should be smooth and consistent.
* sudden plunge suggests breaking out of the pedicle laterally.
* an increase in resistance indicates abutment against the pedicle or vertebral body
cortex.
Step 4: After cannulation, the pedicle sounding probe is placed into the pedicle that is
then palpated from within to make sure there is not a medial, lateral, rostral or caudal
disruption in the cortex of the pedicles.
* sound should also be used to determine that there is bone at the bottom of the pilot
hole verifying that penetration of the ventral cortex of the vertebral body has
not occurred.

24. Pedicle Screw Entry Sites and
Trajectory
Step 5: After pedicles have been probed, one can either:
a. place Steinman pins or K-wires bilaterally or unilaterally into the pedicles to confirm
the trajectory and entry site and then go to (b) below:
b. tap the pedicle screw path if non-self tapping screws are used; then go to c. below:
c. place the permanent screws with the longest diameter that will not fracture the
pedicle.
* length of the screw can be determined by measuring the length of he Steinman pin/
K-wire/pedicle probe from the pedicle entry site to a depth of 50-80% of the vertebral
body.
* the screws in the lumbar spine usually have a 4.5 to 7 mm diameter and a 35-50 mm
length.
Step 6: After pedicle screw placement, the transverse process and the lateral aspects of
the facet joints are decorticated, screws are connected to a longitudinal construct,
usually a rod (can be a plate)- these may need to be bent to conform to the proper
curvature of the spine; screws are secured (top-loading or side-loading); bone graf is
then placed on the previously fusion bed.

25. Surgical Treatment
• Fixation methods
• Roy-Camille – midpoint An -
1 mm medial
• Magerl - 2 mm medial to the
midpoint of lateral mass

26. Treatment
• The recommended lateral
angulations for Roy-Camille,
Magerl, and An are 10°,
25°,and 30°
• Magerl and An techniques
have a wide margin of safety.
Caution should be practised
with Roy-Camille's technique
at C3, C4, and C6 levels to
avoid vertebral vessels injury

27. Treatment
• Screw projections were
determined based on . A line
parallel to the vertical axis (A-B)
is drawn over the entry point
(line C-D). The axis of screw will
be represented by a straight line
connecting the entry point of
lateral mass and the point 1.75
mm (based on the 3.5 mm
diameter screw is commonly
used screw) lateral to the border
of vertebral artery canal (line C-
E). The angulation between the
line C-D and the line C-E will be
the minimum lateral angulation
of the lateral mass screw. These
measurements were repeated
from C3 to C6 vertebra.

28. Intraoperative Verification of the
Screw Trajectory and Placement
1. Lateral and an AP radiograph or fluoroscopic image
* this does not guarantee accurate screw placement.
* accuracy can be improved with a slightly oblique AP view- a pin located in the middle
of the
pedicle has a characteristic "target sign".
* direct AP views demonstrate the lateral to medial orientation of the screws.
- excessive medial orientation of the screws seen on AP films raises the concern of
medial
penetration of the pedicle by the screw.
* lateral imaging is useful to view the depth of penetration into the vertebral body and
sagittal
angulation of the trajectory (Figure 6).
- ventral screw penetration is usually between 50 and 80% of the AP diameter of the
vertebral
body; penetration >80% of the vertebral body on lateral plain x-ray raises the concern
of ventral penetration of the vertebral body cortex.

29. Intraoperative Verification of the
Screw Trajectory and Placement
2. Screw placement can be checked
electrophysiologically with direct
stimulation of the pedicle probe or screw
producing an electromyogram (EMG)
response peripherally; if this
response occurs below the threshold
expected for intact cortical bone, the
screws may be redirected or removed.
* For more information on this topic please
refer to Clements et al in Spine 21:600-
604, 1996.
3. Interactive frameless stereotaxy systems
(including fluoronavigation) can be help
guide in he proper placement of the screws.
In the future, such technology will lead to
percutaneous pedicle screw placement-
Stay tuned!!

41. Complication
Screw misplacement
Coupling failure
Superficial wound infection
Deep wound infection
Nonunion
Permanent neural injury
Screw loosening
Screw bending
Screw breakage

44. Tha