Surgical Positions

Surgical procedures require proper patient positioning to keep the patient comfortable and safe during surgery, and to provide the surgeon with easy, unobstructed access to the surgical site. Many factors influence the decision of how to position a patient during a procedure: 

• The patient's overall condition
• Length of procedure
• Techniques to be used during procedure
• Required exposure at operative site
• Expected anatomical and physiological changes associated with anesthesia
• Patient’s risk factor: age, weight, skin condition, mobility/limitation, pre-existing condition, airway etc
• Patient’s privacy & medical needs.

Goals of Positioning:

• Providing adequate exposure
• Maintaining patient dignity
• Optimal ventilation & airway management
• Providing adequate access
• Avoiding poor perfusion
• Protecting fingers, toes, genitals 
• Protecting muscles, nerves, bony prominences.
• Ideal patient positioning involves balancing surgical comfort, against the risk related to the patient position.
• Patient positioning & postural limitations should be considered during the Preanesthetic assessment.

Positioning injuries

1. General/Regional Anesthesia: Physiologic changes & reduced movement/sensation.

2. Pressure: Force placed on Pressure underlying tissue 

3. Shear: Folding of underlying Shear tissue

4. Friction: Force of two surfaces rubbing against one another.

5. Moisture: Produces maceration

6. Heat: Increases metabolism.

7. Cold: Reduces oxygen delivery.

8. Negativity: increases pressure.

9. Nerves: Stretching or compression. Transient or permanent damage.

Classification of nerve injury: 

Neurapraxia: damaged myelin with intact axon. Impulse conduction across the affected segment fails. Mild and reversible nerve injury. Recovery usually occurs in weeks to months and prognosis is good.

Axonotmesis: axonal disruption. Endoneurium and other supporting connective tissue are preserved. Recovery and prognosis is variable.

Neurotmesis: nerve is completely severed. There is complete destruction of all supporting connective tissue structures. Surgery may be required and prognosis is poor.

Most frequent site of injury: Ulnar nerve ( 28%), Brachial Plexus (20%), Peroneal, Facial.

Ulnar Nerve

Most common nerve injury in anesthetised patients

Often injured when compressed between the posterior elbow and arm board or bed, more likely with elbow flexed or forearm pronated, Symptoms include loss of sensation of lateral portion of hand and inability to abduct or oppose the fifth finger (claw hand)

Brachial plexus 

Shoulder, Arm, Hand

• Arm boards extended beyond 90 degrees
• Arm boards higher or lower than the OT bed
• Lateral rotation of the patient’s head
• Leaning against the shoulder or arm
• Shoulder braces. 

Peroneal Nerve

Lower leg, Foot, Toes 

Common peroneal injury due to:

Direct compression, Patients who are thin, Hyperextension of knees, Pressure behind knee, graduated compression stockings too tight, Foot drop/Lower-extremity paresthesia. 

10. Pulmonary: Hypoxia, Respiratory compromise, Decreased oxygen saturation, pulmonary edema, Congestion, Atelectasis.

11. Ocular: Corneal abrasion, Central retinal artery occlusion.

Other risks for positioning injury

Obese or underweight, Poor nutritional status, Advanced age (>70 years), Pre-existing conditions, History of skin breakdown/pressure ulcers, Smoking (vasoconstriction).

Surgical Positions:

There are 4 basic surgical positions

1. Supine, 2. Prone, 3. Lateral. 4. Lithotomy.

Apart from these there are certain variation's that includes:

1. Trandelenburg, 2. Reverse trandelenburg, 3. Fowler’s & Semi-Fowler’s position, 4. Beach-chair position, 5. Wattson jone position, 6. Kraske/Jackknife position, 7. Position for Robotic Surgery.

SUPINE

Most common with the least amount of harm

• Placed on back with legs extended and uncrossed at the ankles
• Arms either on arm boards abducted <90* with palms up or tucked (not touching metal or constricted)

• Spinal column should be in alignment with legs parallel to the OT bed
• Head in line with the spine and the face is upward – Hips are parallel to the spine
• Padding is placed under the head, arms, and heels with a pillow placed under the knees

• Safety belt placed 2” above the knees while not impeding circulation

Risk associated with Supine Position:

Greatest concerns are circulation and pressure points

Most Common Nerve Damage:

• Brachial Plexus: positioning the arm >90
• Radial and Ulnar: compression against the OR bed, metal attachments, or when team members     lean against the arms during the procedure
•  Peroneal and Tibial: Crossing of feet and plantar flexion of ankles and feet
• Vulnerable Bony Prominences: (due to rubbing and sustained pressure) Occiput, spine, scapula, Olecranon, Sacrum, Calcaneous.

Variations:

Lawn Chair Position

• Back of the bed is raised.

• Legs below the knees are lowered at an equivalent angle.
• Slight trandelenberg hilt.

Advantages:

1. Better tolerated by awake patient or under monitored anaesthesia care.

2. Venous drainage from lower extimities enhanced.

3. Xiphoid to pubic distance reduced & easing closure of laprotomy incision.

Trandelenberg Position

The patient is placed in the supine position while the OR bed is modified to a head‐down tilt of 35 to 45 degrees resulting in the head being lower than the pelvis

• Arms are in a comfortable position – either at the side or on bilateral arm boards
• The foot of the OR bed is lowered to a desired angle.

ADVANTAGES

• To increase V.R after spinal anaesthesia
• To increase central venous volume to facilitate central cannulation
• To minimise aspiration during regurgitation. 

Risk associated with Trandelenberg Position:

Increased CVP, Increased ICP,  increased IOP, increased myocardial work, increased pulmonary venous work, decreased pulmonary compliance, decreased FRC, Swelling of face, eyelids, conjunctiva, tongue, laryngeal edema observed in long surgeries.

Reverse Trandelenberg

• The entire OT bed is tilted so the head is higher than the feet
• Used for head and neck, laproscopic procedures

• Facilitates exposure, aids in breathing and decreases blood supply to the area
• A padded footboard is used to prevent the patient from sliding toward the foot
• Reduces venous return therefore hypotension
• Laproscopic cholecystectomy : reverse trendelenburg position with right up

Lithotomy Position

• With the patient in the supine position, the hips are flexed to 80‐100 o from the torso so that legs are parallel to it and legs are abducted by 30‐45 o to expose the perineal region

• The patient’s buttocks are even with the lower break in the OR bed (to prevent lumbosacral strain)
• The legs and feet are placed in stirrups that support the lower extremities

• The legs are raised, positioned, and lowered slowly and simultaneously with the permission of the anaesthesia care provider
• Adequate padding and support for the legs/feet should eliminate pressure on joints and nerve plexus

• The position must be symmetrical
• The perineum should be in line with the longitudinal axis of the OT bed.

 Risk associated with Lithotomy Position:

Preload increases, causing a transient increase in CO , cerebral venous and intracranial pressure

• Reduce lung compliance

• If obesity or a large abdominal mass is present (tumor, gravid uterus)‐ VR to heart might decrease
• Normal lordotic curvature of the lumbar spine is lost potentially aggravating any previous lower back pain

Lateral Position

• Shoulder & hips turned simultaneously to prevent torsion of the spine & great vessels
• Lower leg is flexed at the hip; upper leg is straight
• Head must be in cervical alignment with the spine
• Breasts and genitalia to be free from torsion and pressure

• Axillary roll placed caudal to axilla of the downside arm (to protect brachial plexus)
• Padding placed under lower leg, to ankle and foot of upper leg, and to lower arm (palm up) and upper arm
• Pillow placed lengthwise between legs and between arms
•  Stabilize patient with safety strap and silk tape, if needed 

Lateral Position with Kidney bridge

Flexed lateral decubitus position. Point of flexion should lie under iliac crest, rather than the flank or lower ribs, to optimize ventilation of the dependent lung.

Park‐bench position: (SEMI‐PRONE POSITION)

Modification of lat. position.

Better access to posterior fossa.

Upper arm positioned along lateral trunk & upper

Shoulder is taped towards table.

Prone- Position

• Access to the posterior fossa of the skull, the posterior spine, the buttocks and perirectal area, and the lower extremities
• Arms: tucked in the neutral position /placed next to the patient's head on arm boards—sometimes called the prone “superman” position/Extra padding under the elbow – prevent ulnar nerve

• When GA is planned, the patient is intubated on the stretcher/ i.v access is obtained/ETT is well secured/pt is turned prone onto the OT table/disconnect blood pressure cuffs and arterial and venous lines that are on the side to avoid dislodgment
• Disconnection of pulse oximetry, arterial line, and tracheal tube, leading to hypoventilation, desaturation, hemodynamic instability, and altered anesthetic depth. Therefore it’s best to keep pulse oximetry and arterial line connected
• ETT position is reassessed immediately after the move

 Head Position

Turned to the side (45 degrees) if neck mobility is fine.

Check the dependent eye for external compression.

Maintained by surgical pillow, horseshoe headrest, or Mayfield head

pins mostly, including disposable foam versions, support the forehead, malar regions, and the chin, with a cutout for the eyes, nose, and mouth

Head Support devices used in Pron

1. Mirror System.

2. Horse Shoe rest.

Risk associated with Prone Position:

Increased intra‐abdominal pressure decreases FRC, compliance and increased PAP and transmits elevated VP to the abdominal and spine vessels‐increase bleeding risk.

• Its imp that the abdomen hangs free and moves with respiration‐ space of atleast 6 cms!
• Thorax: firm rolls or bolsters placed each side from the clavicle to the iliac crest ( wilson frame, jackson table, relton frame)
• Pendulous structures (e.g., Male genitalia and female breasts) should be clear of compression

? Its essential to check the ETT position at a required degree of flexion

Fowler’s or Semi-Fowler’ position

• Patient begins in the supine position
• Foot of the OR bed is lowered slightly, flexing the knees, while the body section is raised to 35 – 45 degrees, thereby becoming a backrest
• The entire OR bed is tilted slightly with the head end downward (preventing the patient from sliding)
• Feet rest against a padded footboard

• Arms are crossed loosely over the abdomen and taped or placed on a pillow on the patient’s lap 
• A pillow is placed under the knees.
• For cranial procedures, the head is supported in a head rest and/or with sterile tongs
• This position can be used for shoulder procedures ( BEACH CHAIR POSITION)

 Risk of Beach Chair Position:

• Venous air embolism
• Cerebral injury due to hypotension therefore essential to measure CVP at brain level since for every 2.5 cm diff b/w BP cuff and brain – 2 mmHg fall in BP.

Sitting Position

• This is actually a modified recumbent position as the legs are kept as high as possible to promote venous return

• Arms must be supported to prevent shoulder traction.
• Head holder support is preferably attached to the back section of the table.

ADVANTAGE

•  Excellent surgical exposure
• Reduced perioperative blood loss
• Superior access to the airway
• Reduced facial swelling
• Improved ventilation, particularly in obese patients

Points to remember in neurological Patients:

Head Positioning :

Ideal position of head for Craniotomies & spine procedures based on the 2 principles:

•  An imaginary trajectory from the highest point at skull surface to area of interest in brain should be the shortest distance between the 2 points.
• The exposed surface of the skull & an imaginary perimeter of craniotomy should be parallel to the floor

Types of Craniotomies:

A. Ant. Parasagittal

 B.  Frontosphenotemporal

C. Sub‐temporal

D. Lat Sub‐occipital

E. Midline Sub‐occipital

F. Post. Parasagittal

 Head & Neck Positioning:

• Head safely rotated b/w 0‐45°.
• For more rotation, a roll/pillow place under the opposite shoulder.
• Maintaining 2‐3 finger breadths thyromental distance during neck flexion

Orthopedic Surgery Position

• Body section to support head & thorax Sacral plate for pelvis
• Perineal post adjustable foot plates,
• Table maintains traction of the extremity Allows surgical & fluroscopic access
• Anesthesia induced & then the patients are positioned on this table . Arm on Side

 Problems with jone’s position:

• Brachial plexus injury due to > than 90* extension of the upper limb
• Lower extremity compartment syndrome due to long surgeries & compression
• Pudendal nerve injury Due to pressure of the perineal post

Positioning in Robotic Surgery:

•  Robot‐assisted laparoscopic surgery(RALS) ‐ referred to as da Vinci surgery‐used for gynecologic, urological, and gynecologic oncology procedures.
• Pt is placed in dorsal lithotomy and steep trendelenburg position.(30‐45o table tilt)

Steps to avoid slipping of patient are:

• Place an surgical sheet made of antiskid material on the OT bed.
• Placing surgical gel pads against a patient’s bare skin.
•   Use of the Bean Bag Positioner

Risk associated with Robotic Surgery positioning:

The risks are same as in trandelenberg position.

• Rhabdomyolysis
• Corneal abrasions
• Prolonged surgery
• Difficult immediate access to the airway & iv
• Fixed position of the robot may cause injury if the position is changed
• Monitoring is difficult.