Surgical Positioning

“A team effort”

Perioperative Peripheral Nerve Injury

Nerve Injuries

• Transection- by trauma/surgical maneuvers

• Compression- pressed against a hard object

• Stretch- a long course across many structures

• Kinking- pinched between 2 immovable structures

Peripheral Nerve Injury

Ischemia

Tissue

edema

Further ischemia

In reversing motor nerve damage, time is of the essence: 'Wait and see' in injuries like carpal tunnel syndrome may

miss a window for recoveryDate:October 9, 2011Source:Children's Hospital BostonSummary:When a motor nerve is severely damaged, people rarely recover full muscle strength and function. Combining patient data with observations in a

mouse model, neuroscientists now show why. It's not that motor nerve fibers don't regrow -- they can -- but they don't grow fast enough. By the time they get to the muscle fibers, they can no longer communicate with them.

Children's Hospital Boston. "In reversing motor nerve damage, time is of the essence: 'Wait and see' in injuries like carpal tunnel syndrome may miss a window for recovery." ScienceDaily. ScienceDaily, 9 October 2011. <www.sciencedaily.com/releases/2011/10/111003131423.htm>.

Factors contributing to injuries: TIME & PRESSURE

Positioning devices

Anesthetic Technique

Length of Procedure

Body habitusPre-existing conditions

Ulnar Nerve

The ulnar nerve is a

branch of the medial cord

of the brachial plexus

Positioning the Ulnar Nerve

Supinate the arm

Abduct less than 90 degrees

Use padding

Ulnar Nerve Injury

Ulnar Neuropathy is the most frequently reported injury

Elbow flexion may compress the nerve in

the cubital tunnel

Occurs predominantly in men, causes are multifactorial.

Ulnar Neuropathy

“Claw Hand”

Brachial Plexus

Susceptible from compression or stretch

of thevertebrae,

clavicle,first rib

or humeral head

Causes of injury to Brachial Plexus

Shoulder bracesmay compress nerve roots

and stretch the plexus

Turning the head(unconscious patient)

may stretch thebrachial plexus

Spreading the sternal retractor causes the clavicle and rib to pinch the plexus. Unilateral retraction may cause stretching of the nerves.

Peroneal NerveThe nerve is

superficial and fixated to the fibular head

Regardless of the device, prevent

compression of the nerve against the

device.

Injury results in foot drop and

inability to evert the foot.

Corneal Abrasion&

Postoperative Vision Loss (POVL)

Corneal Abrasion

• The most common perioperative eye injury

• Causes include trauma, drying or swelling from the

dependent or prone position

• Is very painful

• Treatment is usually supportive and may include an

antibiotic ointment

• symptoms mostly resolve within days but may take up

to 2 months.

Techniques to prevent corneal abrasion

Protect the eyes

during general

anesthesia

Prevent drying

or trauma to the eyes

Postop Vision Loss (POVL)

•A rare but devastating outcome

•Associated with spine, orthopedic joint, and

cardiac surgery; may include robotic procedures

•Incidence is increasing

•Contributing factors may include time spent in

position, eye compression, increased IOP,

hypoperfusion, anemia.

5 Causes of POVL

•Ischemic optic neuropathy (ION) - ↓ perfusion, ↑ IOP•Central retinal artery occlusion (CRAO)- eye compression, hypertension, cardiaopulm. bypass•Central retinal vein occlusion-hypertension, obesity, glaucoma, sickle cell anemia•Cortical blindness- trauma or ischemia: emboli, hemorrhage, ↓↓BP•Glycine toxicity –transient blindness due to high blood ammonia levels

Prevention of POVL (?)• Positioning – limit prone position to < 6 hours, limit steep

Trendelenburg to < 1 hour, consider head pins or tongs to prevent

eye compression and proper alignment of head.

• Blood pressure - consider an arterial line for scrupulous

monitoring, consider the monitoring site (external auditory

meatus/Circle of Willis) for the sitting position, keep MAP at 20-25%

of baseline, use pressors prn

• Fluid therapy – crystalloid should not exceed 40ml/kg regardless of

duration of spine surgery, consider using CVP to guide fluid

management

• Anemia – consider transfusing for HCT <26%, maintain HCT ≈32%

Other Position Related Injuries and Complications

Spinal Cord InjuryFlexion of the head during sitting or prone cases may create ischemia from the compression and stretch of the cord. Venous congestion, along with hypotension results in decreased perfusion of the cord.

Compartment Syndrome•An injury creates swelling, increased pressure, within a

muscle compartment resulting in nerve and vascular damage.

• Some perianesthesia causes may include:fluid extravasationcrushing/compressing injuries lithotomy position lateral decubitus position pneumatic compression boots limb straps prolonged periods of frequent NIBP cycling

Venous Air Embolism (VAE)•May occur whenever there is a negative pressure gradient

between the heart and the veins at the operative site.• Incidence estimated 1-76%

• Gold standard for detection is TEE, but reality lies with cost/ benefit of procedure.

• Precordial Doppler, placed between the 3rd and 6th

intercostal space on the right, may be used

• Esophageal stethoscope may detect a “mill wheel murmur”

Treatment of VAE

Prevent further air entry Treat the intravascular air

Notify surgeon to flood the field Aspirate right atrium

Jugular compression Discontinue N2O

Lower the head Administer 100% O2

Advance to ACLS if needed

Endotracheal Tube (ET) Displacement

The risk of extubation exists whenever the patient is moved or re-positioned.

Disconnect the circuit from the ET when a patient is moved.

Administer 100% O2 until the move is safely completed and ventilation is verified.

With flexion the ET moves downward and

may enter the right mainstem bronchus

Edema of the Face, Tongue or Upper Airway

Periorbital edema from the prone position, excessive fluid administration or obstructed jugular venous return from excessive head flexion.

Tubes/airways may compress tissue and limit lymphatic drainage which may produce swelling or tissue necrosis.