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Anaesthesia for Pituitary Tumour

Surgery

Lim Wee Leong

Neuroanaesthesia Symposium

Kota Bahru

15th Dec 2012


A short word on where I come from


Centre for Traumatology, Neuro-Spine

and Infectious Diseases


It used to be a

Leprosorium

Page • 4


We’re the first hospital in Malaysia to start

collecting money before patients see the doctor.


Operating Schedule in neuro-related surgery

(Two dedicated theatres)

• Monday, Wednesday, Friday: Whole day List

• Tuesday/Thursday: Interventional neuroradiology

• Saturday: Half-day OT (Cranioplasties

Cranioplasties)

• Ortho-spine: Scoliosis, etc

• Emergencies: TBI take the bulk of workload

• We are recognized for Neuroanaesthesia

subspeciality training (3 year programme)


Propofol

Induction dose 1mg/kg over 20 sec

Follow by 10mg/kg/hr for 10 min , 8mg/kg/hr for 10 min, 6mg/kg/hr thereafter

“10 – 8 – 6 “ Rule

Remifentanil

0.5ug/kg/min at induction, 0.25ug/kg/min after tracheal intubation

Then adjust by 0.05ug/kg/min according to haemodynamic status


Introduction

• Tumours of pituitary gland represents

approximately 10% of diagnosed brain neoplasms

• Transsphenoidal resection of pituitary brain

tumours may account for as much as 20% of all

intracranial operations performed for primary

brain tumours


Outline

• Pituitary physiology and pathology

• Different approaches for hypophysectomy

• Perioperative anaesthetic considerations

Pre-operative

Intra-operative

Post-operative


Anatomy and physiology


Anatomy

• The large anterior lobe or adenohypophysis and

the smaller posterior lobe or neurohypophysis

• The gland averages 6 × 13 × 9 mm3

• Lie within the pituitary fossa or sella turcica

• Bounded by the roof of the sphenoid air sinus

and cavernous sinuses which contain the

carotid arteries and the third, fourth and sixth

cranial nerves


Endocrine glands in the human head and neck and their hormones


Pituitary Gland Pathology


Pituitary GH-secreting Tumours

• Acromegaly in the adult and gigantism before

epiphyseal closure

• Annual incidence of acromegaly is 6-8 cases per

million

• Insidious in onset, characterized by enlargement of

the jaw, hands and feet and increased soft tissue

growth

• Associated complications of the disease

‣ diabetes mellitus and hypertension


Affected area

Face

Clinical features of acromegaly

Clinical features

Increase in size of skull and supraorbital ridges; enlarged lower jaw;

increase in spacing between teeth/malocclusion

Hands and feet

Mouth/tongue

Soft tissue

Skeleton

Cardiovascular

Endocrine

Other

Spade-shaped; carpal tunnel syndrome

Macroglossia; thickened pharyngeal and laryngeal soft tissues;

obstructive sleep apnoea

Thick skin; doughlike feel to palm

Vertebral enlargement; osteoporosis; kyphosis

Hypertension; cardiomegaly; impaired left ventricular function

Impaired glucose tolerance; diabetes

Arthropathy; proximal myopathy


Cardiovascular

• Ischemic heart disease

• Cardiomyopathy

• Congestive heart failure

• Arrhythmias

• Hypertension

Complications of Acromegaly

Neurologic

•Carpal Tunnel syndrome

•Stroke

Neoplastic

•Colorectal

•(Breast and prostate - uncertain)

Respiratory

• Kyphosis

• Obstructive sleep apnea

Metabolic

• Diabetes mellitus/IGT

• Hyperlipidemia

Musculoskeletal

•Degenerative arthropathy

•Calcific discopathy, pyrophosphate

arthropathy

http://www.endotext.com/neuroendo/neuroendo5e/neuroendoframe5e.htm


Cushing’s s Disease


Central Obesity in Cushing’s s Disease

William’s Textbook of Endocrinology. 8 th Ed. Foster, DW, Wilson, JD (Eds), WB Saunders, Philadelphia, 1996


Affected area

Appearance

Clinical features of Cushing’s

Redistribution of body fat ’moon face’ truncal obesity

or buffalo obesity

Muscloskeletal proximal myopathy, Osteoporosis (increases risk of

fractures during positioning),vertebral collapse.

Soft tissue

Metabolic

Skin fragility with easy bruising (cannulation difficult),

hirsutism ,acne.

Hypernatremia, hypokalemia, alkalosis.

hypertensive; ischemic heart disease and left ventricular

Cardiovascular

hypertrophy are also common.

Endocrine diabetes

Sleep apnea; Immunosuppression and coexisting

Other

infection, gastroesophageal reflux, renal stones, mental

problems.


Airway Management may be problematic

Buffalo Hump


Prolactinomas

• Prolactinomas are the most frequently observed

type of hyperfunctioning pituitary adenoma

• Represent 20%–30%

of all clinically recognized

tumours.

• More than 90% of patients respond to medical

therapy with a dopamine agonist such as

bromocriptine and thus few patients present for

surgery


Non-Functioning Adenomas

• More likely to be macroadenomas

• Symptoms related to mass effect

Most common :

• Chromophobe adenomas

• Craniopharyngiomas

• Meningiomas


Mass

Effect


Mass effect


Hypopituitarism

• Low levels of peripheral hormones, not associated with

high pituitary tropic hormones.

• Pituitary apoplexy: : present with sudden headache, loss of

vision, loss of consciousness and panhypopituitarism,

requiring urgent surgery.

• Requires glucocorticoid replacement

• Thyroxine replacement is also required (50–150 ug daily).

• Perioperatively, these patients are extremely sensitive to

anaesthetic agents, , and pressor agents may be needed to

maintain blood pressure.


Surgical Approach

• The pituitary fossa can be approached using the

transsphenoidal, transethmoidal or transcranial

route

• The transsphenoidal route is preferred for all

except for large tumours

• Transsphenoidal access to the pituitary fossa is

obtained using a sublabial or endonasal approach


Transsphenoidal Approach to the Sella

Turcica for Pituitary Surgery


Positioning for Pituitary Surgery

• Supine

• Head elevated

• Patient closer to the right

hand side of the table

• Neck tilted laterally to

the left, slightly extended

and secured in a mayfield

clamp


Surgical Approach

Transsphenoidal Approach

Advantages

• Decreased diabetes

insipidus

• Magnified visualization

• Decreased frequency of

blood transfusions

Transcranial Approach

Advantages

• For pituitary tumors that

have significant suprasellar

extension

• Less surgical stimulation


The Ideal Team for Pituitary tumour surgery

• Neurosurgeon

• ENT Surgeon

• Endocrinologist

• Anaesthetist

• Intensivist


Perioperative Considerations

• Pre-Operative Assessment

• Anaesthetic Management

• Post-operative Considerations


Perioperative considerations


General issues with Anaesthesia for Pituitary surgery

• Optimization of cerebral oxygenation

• Maintenance of hemodynamic stability

• Provision of conditions that facilitate surgical

exposure

• Prevention and management of intraoperative

complications

• Rapid, smooth emergence


Common Surgical Problems with Pituitary Surgery

1. Carotid artery injury

2. Central nervous system injury

3. Hemorrhage/swelling of residual tumor

4. Loss of vision / Ophthalmoplegia

5. Cerebrospinal fluid leak

6. Meningitis

7. Nasal septum perforation / Postoperative epistaxis /

Postoperative sinusitis

8. Anterior pituitary insufficiency

9. Diabetes insipidus

10. Death


Complications of Transsphenoidal Surgery

Outcome Measure Incidence (%)

Mortality


Perioperative Considerations

• Pre-Operative Assessment


Preoperative assessment for pituitary tumours

• General status

• Visual function

• Airway assessment

• Signs and symptoms of raised intracranial pressure

• Endocrine assessment

• Effects of hormonal hypersecretion

• Co-morbidities, particularly in acromegaly or

Cushing’s s syndrome


Cardiac Assessment:

Commonly associated with hyper-secretion from

pituitary acromegaly and Cushing's disease

• Left ventricular hypertrophy

• Coronary artery disease

• Arrhythmias

• Conduction disturbances

• Valvular heart diseases

• Cardiomyopathies

• Congestive heart failure

Investigations:

• ECG

• CXR

• Cardiac ECHO


Hormone replacement for patients undergoing

pituitary surgery

• All patients with pituitary disease need endocrine

assessment

• Preoperative hormone replacement therapy should

be continued into the operative period

• In general, All patients with Cushing’s s disease

require glucocorticoid cover


Pituitary adenoma for surgery

0800 hours cortisol and short ACTH 1–24 (synacthen)

Normal

(cortisol >550 nmol/L)

Abnormal

No Perioperative

Glucocorticoid

Cover

Cortisol for 1-3 days

The patient should be given supra-

physiological glucocorticoid cover for 48 h

• Hydrocortisone 50 mg iv 8-hourly on day 0

• 25 mg iv 8-hourly on day 1

• 25 mg iv at 0800 hours on day 2

Cortisol for 3-6 days


Perioperative Considerations

• Anaesthetic Management


Perioperative Considerations

• Anaesthetic Management

Anesthetic techniques

Airway management

Monitoring and intraoperative complications

Emergence and recovery


Anaesthesia Technique

• Both balanced anaesthesia and Total

intravenous anaesthesia (TCI) have been

used with good results

• Choice of anaesthesia depends on

personal preference

• Personal Opinion: No difference


Anesthetic Technique

• Whether an inhalational or intravenous technique is

employed, short-acting agents should be utilised to

facilitate rapid recovery

• Titrate muscle relaxants intra-operatively especially if

patient has h/o skeletal muscle weakness

• Target for post-op extubation

• Postoperative airway maintenance is an issue of

concern

(Prone to subglottic stenosis)


Monitoring and Lines

• At least one large peripheral line (>18G)

• When using TCI, I always use a dedicated venous line

for Propofol/Remifentanil

infusion

• I always have intra-art monitoring

• You should have a central line for fluid/electrolyte

monitoring

• Urine output is a must

• ECG, SpO2, Temperature monitoring

• I tend to use BIS monitoring if using TCI


Airway management

• General Anesthesia with endotracheal

intubation is indicated

• If difficult airway anticipated, then the

intubation technique must include availability

of devices for difficulty airway management

• Throat pack needed for transphenoidal

approach


Airway management

• Reinforced orotracheal tube is recommended

• Positioned in the left corner of the mouth

• Throat pack is then inserted

Prevents bleeding into the glottic region during surgery,

and entry of blood and secretions into the stomach

which may precipitate postoperative vomiting


Reason:

Over-secretion of the GH causes macroglossia, hypertrophy and thickening

of soft tissues of the oro-pharynx and enlargement of the soft palate,

epiglottis and ari-epiglottic fold.

Conclusions:

Anesthesiology, V 93, No 1, Jul 2000

The incidence of difficult laryngoscopy and intubation in acromegalic

patients is higher than in normal patients. . Preoperative Mallampati scores of

3 and 4 were of value in predicting difficult laryngoscopy. Nevertheless,

even this test will miss a significant number of patients with a difficult

airway.


Airway Management

• Airway management and tracheal intubation proceed

uneventfully in the majority of patients if large face

masks and long-bladed laryngoscopes are used

• Fibreoptic intubation should be considered in patients

in whom difficult airway management is predicted

(recommended for grades 3 and 4)

• Equipment for emergency tracheostomy should be

available if airway changes are advanced


Four grades of airway involvement

in pituitary acromegaly

Grade 1: No significant involvement

Grade 2 : Nasal and pharyngeal mucosa

hypertrophy but normal cords and glottis

Grade 3 : Glottic involvement including glottic

stenosis or vocal cord paresis

Grade 4 : Combination of grades 2 and 3, i.e. Glottic

narrowing with soft tissue abnormalities


Options for difficult airway management


Why I prefer awake fiberoptic

intubation

It is the only technique where I paralyse

the patient only AFTER I secure the airway!

Most other intubation techniques require me to give

my anaesthesia or use of muscle relaxants BEFORE

I secure the airway.


Maintenance of anaesthesia

• short-acting agents are used to allow rapid

recovery at the end of surgery

• During transsphenoidal surgery, ventilation to

normocapnia should be employed. (Excessive

hyperventilation will result in loss of brain bulk and

make any suprasellar extension of the tumour less

accessible from below)

• Longer-acting opioids are administered at the

end of surgery


Perioperative Considerations

• Post-operative Considerations


Emergence from Anaesthesia

• Smooth and rapid emergence from anaesthesia is

essential to allow early neurological assessment

and maintenance of stable respiratory and

cardiovascular variables

• At the completion of surgery, the oropharynx

should also be suctioned meticulously

• Removal of pack

• Avoid coughing as it may dislodge the autologous

fat packing (CSF rhinorrhoea)


Do not forget to

tell your patient

that they have to

breathe from the

mouth after the

surgery.


In patients with a history of OSA

• Oral airway to facilitate mouth breathing

• A nasopharyngeal airway can also be placed

under direct visualization by the surgeons before

the nose is packed patients prone to upper

airway obstruction may

• Tracheal extubation in a seated position

• Use NSAID’s s instead of opioids for post-op

analgesia


Post-Operative Analgesia

Post-op analgesia

Small doses of IV Morphine

IV Paracetamol

Non-steroidal anti-inflammatory drugs

Tramadol (less effective and may cause more

sedation)


Perioperative Considerations

• Disorders of Water Balance


Disorders of Water Balance

DI

SIADH


Diabetes Insipidus

• Failure of ADH release from the posterior pituitary

• Hallmark of DI is dilute urine in the face of hypertonic

plasma.

• Aqueous vasopressin (5 units sc every 4h)

• Desmopressin (DDAVP),

A synthetic analogue of ADH

12-to 24-hour duration of action,

Intranasal preparation (5-10 mg qd or bid)

Used both in the ambulatory

and perioperative settings


Differences between Inappropriate Antidiuretic Hormone

(SIADH) and Diabetes Insipidus (DI)


Post-operative Polyuria


I’m going to ask you some questions


The following are features of Cushing’s

syndrome:

• Hypokalaemia

• Osteoporosis

• Hypertension

• Peptic Ulceration

• Muscle Weakness


The following are features of Cushing’s

syndrome:

Hypokalaemia

Osteoporosis

Hypertension

Peptic Ulceration

Muscle Weakness


Concerning advantages of transphenoidal

approach over transcranial approach:

• Decreased diabetes insipidus.

• Magnified visualization.

• Decreased frequency of blood transfusions

• Less surgical stimulation


Concerning advantages of transphenoidal

approach over transcranial approach:

Decreased diabetes insipidus

Magnified visualization

Decreased frequency of blood transfusions

×Less surgical stimulation


Hypophysectomy will result in

• Depressed Thyroid Function

• Osteoporosis And Generalised Wasting

• The Secretion Of Adrenal Glucocorticoid

And Sex Hormones To A Low Level

• Diabetes Insipidus

• Normal Aldosterone Secretion


Hypophysectomy will result in

Depressed Thyroid Function

×Osteoporosis And Generalised Wasting

The Secretion Of Adrenal Glucocorticoid

And Sex Hormones To A Low Level

Diabetes Insipidus

Normal Aldosterone Secretion


Diabetes inspidus results in

• Hypernatremia

• High plasma osmolarity

• High urine flow

• High urine osmolarity


Diabetes insipidus results in:

Hypernatremia

High plasma osmolarity

High urine flow

×High urine osmolarity


Any

Question


Pituitary Adenomas

Pituitary adenomas can be classified into:

• Microadenomas (1 cm)

Further classification :

• Non functioning tumours

• Functioning tumours


Functioning Adenomas

• Excess of one or more of the anterior

pituitary hormones

• Prolactinomas followed by GH and ACTH

secreting adenomas

• Adenomas secreting thyrotropin or FSH

and LH are rare


Pituitary Adenomas

Page • 91


Cushing’s s Syndrome vs. Cushing’s s Disease

• Cushing’s s syndrome is a syndrome due to excess

cortisol from pituitary, adrenal or other sources

(exogenous glucocorticoids, ectopic ACTH, etc.)

• Cushing’s s disease is hypercortisolism due to

excess pituitary secretion of ACTH (about 70% of

cases of endogenous Cushing’s s syndrome)


Cushing’s s Syndrome

• Moon facies

• Facial plethora

• Supraclavicular fat pads

• Buffalo hump

• Truncal obesity

• Weight gain

• Purple striae

• Proximal muscle weakness

• Easy bruising

• Hirsutism

• Hypertension

• Osteopenia

• Diabetes mellitus/IGT

• Impaired immune

function/poor wound healing


Multiple Endocrine Neoplasia (MEN) Syndromes

MEN I (Werner)

• Parathyroid hyperplasia

• Pituitary adenoma

• Pancreatic islet cell tumors

MEN IIA

• Parathyroid hyperplasia

MEN IIB

• Parathyroid hyperplasia

• Medullary thyroid carcinoma

• Pheochromocytoma

• Ganglioneuromatosis

• Marfanoid habitus

• Medullary thyroid carcinoma

• Pheochromocytoma


Different approaches for Pituitary Surgery


THE FULLY ENDOSCOPIC ENDONASAL APPROACH

ADVANTAGES

• A completely endonasal approach

• A targeted approach

• A more clear visualization - Contact anatomy

• A panoramic view - Angled endoscopes

• A more complete operation leading to a

lower rate of recurrence


Surgical Approach

Transsphenoidal Approach

Disadvantages

• CSF leakage and meningitis

• Inability to visualize neural

structures adjacent to large

tumors

• Possibility of bleeding from

cavernous sinuses or carotid

Transcranial Approach

Disadvantages

• Incidence of permanent

diabetes insipidus and anterior

pituitary insufficiency is

increased

• Damage to the olfactory nerves,

frontal lobe vasculature, and

optic nerves and chiasma

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