THYROIDECTOMY MORBIDITIES

THYROIDECTOMY MORBIDITIES:Preventions & Interventions

ORLINO C. BISQUERA, JR., MD, FPCSDivision of Surgical Oncology, Head & Neck, Breast, Soft

Tissue and Esophago-Gastric SurgeryDepartment of Surgery, UP-PGH

Objectives• Discuss the different thyroidectomy morbidities

with its related anatomy, mechanism of injury,prevention & intervention.– Wound complications

• Hemorrhage• Hematoma• Seroma• Infection

– Nerve injury• Superior layryngeal nerve• Recurrent Laryngeal nerve

– Metabolic Complication• Hypocalcemia

– Other neck injuries• Tracheal injury• Esophageal injury

Wound Complications: Hemorrhage

• Uncommon• Life-threatening - < 1%• Factors for blood loss

– Venous hypertension– Diffuse goiter with increased vascularity– Substernal or intrathoracic goiter– Aberrant blood supply– Anatomical non-familiarity / poor

surgical technique

Hemorrhage: Possible Sources• Anterior jugular

veins• Thyroid vessels

– Superior & Inferior– Middle thyroid– Lobar vessels

• Aberrant bloodsupply

• Absent inferior thyroidartery: 2% - 5%

• Blood supply frombranches of the leftsubclavian artery

Hemorrhage: Potential problems

1. Obscuresidentification ofRLN and

Parathyroidglands

2. Hypotension /Death

High risk for hemorrhage

• Ectopic Goiters– Substernal goiter: More common

– Cervical goiter with enlargement towardsmediastinum

– Blood supply from inferior thyroid artery

– Mediastinal goiter: rare– Intra-thoracic blood supply

Problems:• Control of the inferior thyroid or intra-thoracic

blood supply• Venous hypertension from superior vena cava

compression

Intraoperative Hemorrhage:Prevention

1.Careful attention to surgical technique2.Anticipate potential high risk group

Substernal/Mediastinal goiters Careful planning in surgical approach

Cervical incision alone: Majority With sternotomy: 2% - 6% Extensive Mediastinal extension Mediastinal goiter

Excessive bleeding over avoidance of sternotomy

Hemorrhage: Intervention

Patient’s statusIdentified

source

Stable vital signs Unstable vital signsHypotension

Bleeding vesselIdentified

Excessivebleeding

precludesIdentifying source ofbleeding

*Ligate / repairbleedingvessel

Identify sourceof bleeding

Adequate exposureProximal / distal control

*Ligate / repairbleedingvessel *Resuscitation Effective gauze pack

Resuscitaion

Wound Complication: Hematoma• Incidence: 0% -3%• Factors: Inadequate hemostasis Increased venous pressure - coughing / straining on extubation Bleeding points:

– Temporarily coagulated small vessels– Residual thyroid gland (subtotal / Ligament of berry)– Major arteries and Veins

Hematoma: Manifestations• Majority: within 4 hours

post-op– Neck pain– Swelling with or without

echymosis– Continuous soaking of

dressing– Respiratory distress - “Bull

neck hematoma”• Laryngeal edema from venous

compression• Tracheal compression

– Hypotension

Hematoma: Prevention• Careful attention to

hemostasis before closure– Secured suture knots– Judicious electrocautery use

• Valsalva maneuver• Cough reflex- airway

suctioning– Increase venous pressure– Fills collapsed veins

• Drains / Bulky dressings– Not prevent hematoma– Delay recognition

Hematoma: InterventionKey: Early intervention

1. No airway compromise OR exploration & evacuation

Patient not left alone until hematoma is evacuated

2. Airway compromise (Bull neck) A. Initial bedside intervention

– Release skin,subcutaneous & strapmuscle closure

– Endotracheal intubation B. Operating room exploration &

evacuation

Wound Complication: Seroma

• Incidence: 0% -6%• Cause: Large dead space -Graves disease -Substernal goiter -MCAGPrevention: Placement of drainIntervention: Percutaneous aspiration

Wound Complication: Infection

• Incidence: <2%• Clean operation

– Drain / antibiotic: No effect on infection– Cause: Break in sterile technique Staph aureus

• Intervention– Appropriate antibiotics– Adequate drainage

Morbidity: Nerve injuries

1. SuperiorLaryngealnerve

2. RecurrentLaryngealnerve

Nerve Injury: Superior Laryngeal Nerve

Incidence: 0% - 20%Risk: Proximity to

superior thyroidvessels

Related anatomy:Vagus nerve - SLN Branches: Internal

branch External branch

Not visualized: 25%

Superior laryngeal nerve: anatomy

Internal branch: pierces thethyrohyoid membrane

Sensory innervation-laryngeal mucousmembrane

External Branch: closeassociation with superiorthyroid artery lateral toinferior pharyngealconstrictor

Diverge from the arteryat the upper border of thethyroid lobe to innervatethe cricothyroid muscle

Superior laryngeal nerve injury:manifestation

• Paralysis of cricothyroidmuscle– Lengthen and tenses the

vocal cords• Subtle voice changes• No airway compromise• No hoarseness but

restricted vocal range– Inability for high pitch

• Easy vocal fatiguability– Vocal cord tension

depends only frominternal laryngealmusculature

• Tolerated by mostpatients

• Career-threatening

CRICOTHYROID MUSCLEIntrinsic laryngeal muscleOrigin: side of cricoid cartilageInsertion: Thyroid cartilage lamina & inferior cornuAction: Vocal cord tension

Superior laryngeal nerve injury: Prevention

• Ligate superiorthyroid vesselclose to thethyroid lobe– Individual branch

ligation– Dissection from

medial to lateraldirection whilethe superior poleis retractedinferiorly

Superior laryngeal nerve injury:Intervention

• Delicate terminal fibersof external laryngealnerve– Cannot be repaired

• Speech therapy– Value is limited but may

help in laryngealcompensation

Recurrent laryngeal nerve injury

• Incidence:– Unilateral nerve injury

• Permanent: 1% - 1.5%• Temporary: 2.5% - 5%

– Bilateral nerve injury• Rare

• High Risk: Advanced disease

Recurrent laryngeal nerve:Anatomy

Origin: Vagus NerveRight: recurs behind the subclavian arteryLeft: recurs behind the aortic archNerve courses upward via the tracheoesophageal grooveEnters the larynx at the cricothyroid joint areaFunction: Innervation of internal laryngeal musculature

Non-recurrent: 1%

Recurrent laryngeal nerve:Landmarks for identification

Relationship to inferior thyroid artery Posterior: 50% Between branches: 25% Anterior: 25%

Relationship with inferiorthyroid cornu RLN laryngeal entry: 1 cm below the inferior thyroid cornu (palpable) : constant landmark for RLN identification

Recurrent laryngeal nerve:Mechanisms of injury

• Stretch• Swelling• Transection• Ligation

Recurrent laryngeal nerve injury:Manifestations

• Unilateral injury– Voice limitation and hoarseness– Usually with no airway compromise– Pre-op laryngeal evaluation to determine relationship with thyroidectomy– Rarely with aspiration

• Bilateral injury– Spastic phase

• Adduction of the vocal cords• Airway obstruction after extubation (stridor)

– Relaxation phase• Abducted bilateral vocal cords

– high risk for aspiration– Weak voice

• Slowly the vocal cords assumes paramedian position– Improvement of voice but with more airway compromise

Recurrent laryngeal nerve injury:Preventions

• Good surgical technique• Visualization of its entire course

– Anatomical familiarity• Susceptible areas for injury

1. Ligament of berry– Attaches part of thyroid tissue to the trachea– Closest contact between the nerve & thyroid tissue– Usually RLN courses posterior to it

– 25% courses through it2. Inferior thyroid artery

Posterior: 50% Between branches: 25% Anterior: 25%

ANTERO-MEDIAL RETRACTION OF THYROID

Recurrent laryngeal nerve injury:Intraoperative Intervention

• Nerve ligation• Release ligature

• Unilateral nerve transection• Immediate microsurgical repair

–Prevents vocal cord atrophy• Bilateral nerve transection

• Immediate microsurgical repair• Tracheostomy

Recurrent laryngeal nerve injury:Postoperative Intervention

• Unilateral vocal cord paralysis• Nerve visualized & preserved:

– Supportive– Anticipate return of function in 3 – 6

months• Nerve transected & not repaired

– Laryngoplasty or vocal cordinjection

» Stiffen and medialize the cord» Allow contralateral cord to

appose during speech

Recurrent laryngeal nerve injury:Postoperative Intervention

• Bilateral vocal cord paralysis– Provide more airway while maintaining voice– Options:

• Irreversible procedures– Arytenoidectomy– Transverse cordotomy

» Widens airway» No improvement in voice quality

• Timing: 1 year post-injury

Metabolic Complication:Hypocalcemia

• Temporary: 0.3% - 49% Symptomatic within 2 weeks Resolves within 6 months• Permanent: 0% - 13% Requires calcium / vitamin D to maintain normal calcium 1 year after thyroid surgery

Hypocalcemia after thyroidsurgery: Causes

• Devascularization: direct injury of blood supply or indirectly from hematoma

• Inadvertentremoval ofparathyroid gland

Parathyroid glands: Relatedanatomy

• Vascularsupply

• 90% inferiorthyroid artery

• 10% superiorthyroid artery

Parathyroid glands: Related anatomy

Embryology & LocationsSuperior 4th Branchial pouch Descends with the thyroid Posteromedial surface of the thyroid between upper & middle 3rdInferior 3rd Branchial pouch Descends with the thymus Within a circle ( 3 cm diameter) center is where RLN intersect the inferior thyroid artery

Postoperative Hypocalcemia:Manifestations

• Normal serum calcium: 8.5 -10.5 mg/dl• Symptomatic hypocalcemia: <8 mg/dl• Mild symptoms

– Numbness/ tingling: lips, hands & feet• Chvosteks’s sign – involuntary contraction of

facial musculature upon tapping of cheek overfacial nerve

• Trousseau’s sign- carpal spasm uponocclusion of arm blood supply to systolicpressure for 2 minutes

– Painful procedure, usually not done

Symptomatic Hypocalcemia:Late symptoms

• Untreated initial symptoms• Severe symptoms

– Mental status changes-irritability,disorientation

– Muscle cramps & spasm– Hypotention– ECG-prolongation of Q-T interval– Laryngospasm– Seizure

• Medical emergency

Hypocalcemia: Prevention– Routine identification

of parathyroid glands– Preservation of

parathyroid bloodsupply

• Ligate branches ofinferior thyroid arteryclose to the thyroidgland (tertiary branches)

• Preserve if there isblood supply fromposterior branches ofthe superior thyroidartery

– Careful dissection ofparathyroid gland offthe thyroid capsule

Parathyroid injury: IntraoperativeIntervention

• Questionable viability: duskyparathyroid gland– SCM autotransplantation

• More predictable function than non-viable gland left in situ

• Lowers incidence of permanenthypoparathyroidism

Parathyroid autotransplantation:The technique

• Fragment of non-viabletissue is sent for frozensection confirmation– Mince the other fragments

to 1 mm pieces and place inSCM pocket. Close theoverlying SCM fascia withsuture

• Graft success rate: 50% -100%

• Autotransplanted glandrevascularization: 3 – 6weeks

Postoperative Hypocalcemia:Intervention

• Mild symptoms: requires prompt calciumreplacement– Prevents progression to severe tetany– 15 mg elemental calcium/ kg/dayOral calcium supplementation 2 – 10 gms / day in divided dose (b.i.d – q.i.d )

• Calcium carbonate 650 mg tab = 250 mg elemental calcium• 70kg X 15 =1050 mg elemental calcium/ day = 4 tablets• 2 tabs b.i.d

Oral Calcium Supplement: Needfor Vitamin D

• Inability to maintain Serum calciumabove 8 mg/dl with oral calcium alone

• Oral calcium supplement is requiredbeyond 4th post-op day– Oral calcium dose > 3gms / day– Calcitriol (1,25 dihydroxy vitamin D) p.o.

• BID with 0.5 – 1.0 ug total daily dose– Increase GIT Ca absorption

• Severe symptoms• 10%Calcium gluconate 10 – 30 ml slow IV over 10

minutes– Repeat dose if necessary to reverse symptoms (maintain serum

calcium above 8 mg /dl)– Effect diminishes after 2 hours

• 10% Ca gluconate drip (0.5 – 1.5 mg elementalcalcium/Kg/hr)

• 6 ampules = 6 gms calcium = 558 mg elemental Calcium in in 500 ml D5W• Infusion at 1 ml / Kg / hour over 8 -24 hours• Provides steady calcium supplement while oral calcium is being

absorbed• Monitor calcium q 4 hours• Discontinue drip: Ionized calcium > 1.12 mmol/L

Start oral calcium at once

Postoperative Hypocalcemia:Intervention

Other neck injury: Trachea• Large invasive tumors• Careless dissection of thyroid

from trachea• High risk area: Ligament of berryPrevention: Anterior retraction of

thyroid lobe & isthmus whilepressing trachea downward

Avascular pretracheal planeIntervention:

1. Primary repair2. SCM patch = >1cm defect3. Resection & primary

anastomosis4. Tracheostomy through defect

SCMflap

Resection &anastomosis

Other neck injury: Pharynx /Esophagus

• Rare• Invasive carcinomaPrevention: Gentle dissection Correct dissection plane Anatomical anticipation NGT as esophageal guideIntervention:

Primary repairExtensive esophageal loss

Flap: SCM / pect major Jejunal interposition

SUMMARY• Thyroidectomy morbidities

– Wound complications• Hemorrhage• Hematoma• Seroma• Infection

– Nerve injury• Superior layryngeal nerve• Recurrent Laryngeal nerve

– Metabolic Complication• Hypocalcemia

– Other neck injuries• Tracheal injury• Esophageal injury

Anatomy,mechanism ofinjury,prevention& intervention

Morbidity in thyroidectomy

The best intervention is still PREVENTION!

Division of Surgical Oncology, Head & Neck, Breast,Soft Tissue and Esophago-Gastric Surgery

Department of Surgery, UP-PGH

Serum Calcium• Total serum calcium

– Dependent on serum protein for binding– Low protein Low total serum calcium

– Not reflective of active IONIZED calcium– Correction: Decrease of 1 gm/dl serum protein

• Ionized Calcium: Free– Hypocalcemia: severe - < 1.0 mmol / L mild – 1.0 - 1.12 mmol / L (4.0 mg / dl)

Corresponding Decrease of Total serum calcium of 0.8 mg/dl

IV Calcium administration

• 10% Calcium gluconate slow IV 5 minutes• 10% Ca gluconate drip

• 6 ampules = 6 gms calcium = 540meqs Calcium in in 500 ml D5W• Infusion at 1 ml / Kg / hour• Provides steady calcium supplement while oral

calcium is being absorbed

• Check Magnesium level– Hypo: Impairs PTH secretion Increases PTH resistance

Calcium carbonate tablet: MildHypocalcemia

• 650 mg tab = 250 mg elemental calcium• Treatment: 15 mg / kg / day

• 70kg X 15 =1050 mg / day = 4 tablets• 1 tab q.i.d

Calcium gluconate drip: SevereHypocalcemia

• 100mg / ml X 10 ml ampule = 1 gm Ca = 93 mg ofelemental calcium

• 93 X 6 ampules = 558 mg elemental calcium• Mix in 500 cc D5W = 1mg /ml

• 70 kg x 0.5 mg elemental calcium/kg/hr = 35mg• 35 ugtt /min = 35 cc / hr = 35 mg /hr

• Objective: 0.5 -1.5 mg elemental calcium /kg/hr infusion over 8 -24 hours : Discontinue infusion – Cai >1.12 mmol/L• Measure ionized calcium q 4 hours