This document discusses anesthesia considerations for scoliosis surgery. It begins by defining scoliosis and describing factors like the Cobb angle that determine surgical indications. It then covers preoperative evaluation and preparation, including tests to assess pulmonary and cardiac function. Intraoperatively, anesthesia aims to control blood loss and preserve spinal cord function using techniques like prone positioning, evoked potential monitoring, hypotensive anesthesia and steroid administration if needed. Postoperative care focuses on pulmonary toilet, fluid management to prevent hyponatremia, and pain control during recovery. New minimally invasive surgical techniques may further reduce complications and blood loss.

1. ANESTHESIA FOR
SCOLIOSIS SURGERY
BY
D.Mohamed mostafa

2. ANESTHESIA FOR SCOLIOSIS
SURGERY
What is scoliosis?
What I have to know about the curve?
• Site
• Location
• Extent
• Degree
• Onset
• Cause

6. Clinical significance of
Cobb’s Angle
• Angle < 10 normal curvature
• Angle > 25 raised pulmonary artery
pressure
• Angle > 40 surgery is indicated
• Angle > 65 restrictive lung disease
• Angle > 100 severe pulmonary dysfunction.
• However, patients with neuromuscular type
may have a much more profound decrease
in pulmonary function for any given curve
severity

7. Causes of Scoliosis
• Congenital
• Idiopathic: 70% of cases
• Mostly in females . On the rt. Side.
• Neuromuscular: cerebral palsy,dysautonomia,
poliomylities and dystrophic myopathy ,myotonia.
• Traumatic: fracture, radiation, burn, surgery
• Syndroms: neurofibromatosis, Marfan S
Ehler Danlos.

8. Pathophysiology
Respiratory abnormalities:
Hypoxia
↑Pulmonary artery pressure.
Restrictive lung disease (↓lung volumes).
↓ Chest wall compliance
Abnormal ventilatory drive
Chronic infection.
arterial blood gases: early:
↓PaO2 only BUT late ↑PaCO2 .

9. Cardiovascular changes
• Pulmonary hypertension.
• Rt. Vent. hypertrophy. Rt. Atrial enlargement
• Rt. Vent. failure.
• Mitral valve prolapse.
• Associated conditions:

10. Spinal Fusion
• The goal of scoliosis surgery is to
achieve spinal fusion from one
vertebra above the curve to one
below. Instrumentation is inserted
to keep spine in best possible
position.
Harrington rod, sublaminar wiring

11. Preoperative assessment
• History .
.
• Examination.
• ECG.
• Echocardiography.
• Pulmonary function tests.
• Arterial blood gases

12. Preoperative preparation
• Clear chest infection .
• Wake up test.
• Posibility of post operative mechanical ventilation
Premedication
Heavy sedation should be avoided in severe
scoliosis.

13. Anesthetic Problems associated
with Scoliosis Surgery
• Problems related to the patient:
1) Respiratory , cardiovascular
neuromuscular abnormalities or
syndromes.

14. Problems related to the surgery
1. Prone position
2. Blood loss and third space loss
3. Lengthy operation
4. Preservation and monitoring of
spinal cord function.
5. Heat loss.

15. Monitoring
• Routine monitors: oximeter, ECG,
capnography, and core body tempe
• Arterial catheter to monitor beat to beat
changes.
• CVP
• Urinary catheter
• Blood loss and replacement are monitored.
• Patient’s position

16. Induction of anesthesia
• Two large intravenous lines
• IV agent other than ketamine is used.
• A loading dose of fentanyl : 1-3µg/kg then
continuous infusion : 5 µg/kg/hr.
• Suxamethonium. is avoided in paralyzed
patients or neuromuscular aetiology.
• Intermediate non depolarizing ms. relaxent
like cis-atracurium or Vecuronium is used
for intubation and maintenance of
relaxation.

17. Positioning of patient
Prone position :
• CVS
• Respiration
• Head and neck.
• Nerves
• Air way : armoured tube
• Soft tissues
Use Relton-Hall operation frame
Reassessment of patient position is
advisable at regular intervals.

19. Maintenance of anaesthesia
• Aim: smooth and continuous anaethesia.
• Avoid bolus dosing of i.v drugs and /or
change in conc. of inhalational agents.
• Nitrous oxide in oxygen + narcotics + inter
mediate ms. relaxant + inhalational agent
<1MAC
• IPPV.
• Fluid therapy (warmed).

20. Blood loss
• 1) Surgical factors
• 2) Increased arterial or venous
pressure.
• 3) Postural factors
• 4) Respiratory factors: e.g.. IPPV

21. Measures taken to reduce blood loss and
need for homologous blood transfusion
1. Proper anesthetic management
2. Infiltration with epinephrine 1/200,000 not
exceeding the upper limit
3. Isovolaemic haemodilution.
4. Use hypotesive anesthesia.
5. Use predonated autologous blood .
6. Cell salvage .

22. Hypotensive anesthesia
• Only used in appropriate patients.
• Blood pressure is lowered to a mean value of 50-60
mmHg BUT high risk patients : 65 mmHg.
Patients who are considered at high risk are:
1. Those with rigid deformity (angle > 120).
2. Those with associated kyphosis.
3. Those with neurofibromatosis.
4. Those with congenital scoliosis.
5. Those with pre-existing neurological defecit.
• Potent inhalation agents : Has the disadvantage of
interference with SEP .
Delay in performing the wake-up test.

23. Warning signs during hypotensive
technique
• Note that , the additive effect
of hypotension and surgical
pressure on spinal cord may
result in spinal cord dysfunction.
• Warning signs:
1) Excessive dry field.
2) Dark venous blood.
3) Deterioration of SEPs.
• Should Cardiac arrest occurred
in prone position it would be fatal.

24. Preoperative autologous blood
donation
• Indications:
1. Bl. Loss > 1000 ml.
2. Hb.>11 gm (Hct = 33%).
• In patients weighing > 50 kg → 450 ml each visit.
• In patients < 50 kg use this formula:
Vol. of donated bl. = donor wt. (kg)
450ml 50 kg

25. Acute isovolaemic haemodilution
• Indications:
1. Bl. Loss >1000ml.
2. Base line Hct > 36%.
1-2 units of blood are removed from the patient immediately
before or after induction of anaesthesia,then this vol is
replaced by colloids or crystalloidsto keep the pt
normovolemic but with Hct25%
Typically the target Hb is 25 -27% . ( why 25-27%?)
It allows for substantial haemodilution.
It allows some margin for safety when blood loss beings to occur during
surgery.
Note that:
Blood is retransfused in REVERSE ORDER.
Tachycardia is a WARNING SIGN ,it means hypovolaemia and need for
retransfusion.

26. Intra-operative cell salvage
• Indications:
• Blood loss >1000 ml.
• Blood loss confined to discrete area.
• Characterestics of salvaged blood:
• = Packed RBCs in saline (Hct is 55%).
• No platelets.
• No clotting factors .
• No WBCs.
• Contraindications:
• ??? Oncologic surgery.
• ??? Enteric contamination (abdominal trauma).
• Topical haemostatic agent (gelfoam).
• Amniotic fluid.

27. Monitoring of the spinal cord
• Wake up test .
• Neurophysiological tests(evoked potential):
SSEP and MEP

28. Wake-up test
• TWO ASSISTANTS SHOULD BE PRESENT.
• N20-02+ narcotics+ relaxant +
inhalation
• Hazards of wake up test:
Tracheal extubation.
Air embolism .
Dislodgement of spinal
instrumentation.
Rod fracture

29. 2)Somatosensory Evoked
Potentials
• SEPs monitors spinal cord sensory pathway.
Can be applied continually and in mentally
retarded patient.
• SITES OF STIMULATION
• Median nerve at the wrist.
• Common peroneal nerve at the knee
• Posterior Tibial at the ankle
Injury or ischemia of spinal cord will change
SSEPs .
The change is in the form of increased latency
and decrease of amplitude.

30. Motor evoked potential
• MEP is basically an electomyographic potential
recorded over muscles in the hand or foot in
response to depolarization of the motor cortex
using transcranial magnetic or electrical stimulus.
• These modalities are profoundly affected by
aneasthetic agents, the former will be
unrecordable and the later recordable only during
intravenous aneasthesia .
MEP cannot be recorded in the presence of
complete neuromuscular blockade.

31. Spinal Cord Protection
• 1) Immediate administration of a
cource of corticosteroids is useful.
Methylprednisolone:
a bolus of 30 mg/kg followed by
infusion of 5 mg/kg for 24 hours.
• 2) Reestablish normotension, normooxia
and normocarbia.
• 3) Instruct surgeon to decrease traction
on spinal cord.

32. Extubation of the patient
(A) Extubation may be performed immediately at the
end of the surgery provided that :
Preoperative V.C was accepted.
Procedure was relatively uneventful.
(B) Extubation in the ICU
Indications for postoperative mechanical ventilation:
• (I) The decision may be taken preoperatively if:
• VC was < 30% of predicted value.
• Severe gas exchange abnormality (↑PaCO2).
• Duchenne muscular destrophy.
• Severe cerebral palsy.
• Patient with congenital heart.
• Patient with neurofibromatosis

33. Postoperative mechanical
ventilation(2)
postoperative decision if :
(1) severe face oedema.
(2) (2) PaO2 on mask ↓70 mmHg
(3) (3) respiratory rate > 35 breath /min.
Extubation.

34. Post operative care
• Pulmonary care.
• Fluid management.
• Pain control.
• Laboratory studies.

35. Postoperative pulmonary care
• Deep breathing and cough.
• Antibiotics .
• Bronchodilators.
• Theophylline.
• Postoperative pain relieve.

36. Fluid management
• SIADH is common.
• Blood:
hyponatremia and hypo-osmolality,
• Urine:
concentrated
decreased urine output and increased
urine osmolality.
Administration of large amount of fluids in an attempt to
increase urine out put will be :
Unsuccessful
Will worsen the hyponatremia.
So administer balanced salt solution aiming at keeping
urine output at the rate of 0.5 ml/Kg/hr.(Furosemide
may be added. Hypertonic saline for severe cases.
Specific treatment is demeclocycline.

37. New Surgical technique:
have used a thoracoscopic technique
through an anterior approach for spinal
fusion and placement of fixation devices.
Blood loss could be reduced to 400
cc and no surgery related
complications were found.

38. THANK YOU