214 A.S. Eiseman

dose administered. The maximum dose of lidocaine that can safely be administered is 4.5 mg/kgm which is approximately 300 mg for a 70-kg subject. If epinephrine is added to the lidocaine, 7 mg/kg can be safely usedm which is approximately 500 mg for a 70-kg subject. 1 A safe dose of epinephrine in the absence of an inhalational anesthetic is 3–5 g/kg/ hr.2 For a 70-kg subject this would equate to 210–350 ml/hr of a 1 :1000,000 solution of epinephrine that contains 1 g/ml of epinephrine.

The following table gives the maximum safe doses for different concentrations of lidocaine with 1 :200,000 epinephrine:

aDose limited by lidocaine toxicity.

bDose limited by epinephrine toxicity.

Tumescent Technique

If the tumescent technique is used, the epinephrine becomes toxic before the lidocaine does if 1 :1000,000 epinephrine is used. Up to 350 cc/hr of 0.1% lidocaine with 1 :1,000,000 epinephrine can be safely utilized. If 1 :2,000,000 epinephrine is used, the lidocaine will become toxic before the epinephrine. Up to 500 cc/hr of 0.1% lidocaine with 1 :2,000,000 epinephrine can be safely utilized. When the tumescent technique is used, the adjunctive local anesthetic that was injected into the superior orbital rims and along the supraorbital and supratrochlear nerves must also be added to the amount of tumescent solution used to prevent toxicity. Usually, 140–180 cc of tumescent solution is all that is needed to anesthetize the forehead region. This added to the more concentrated local anesthetic given falls well short of the maximum safe dose.

References

1.Xylocaine and xylocaine with epinephrine. In: Physicians’Desk Reference, 54th ed. Montvale, NJ: Medical Economics Company, 2000:638.

2.Steinsapir KD, Shorr N, Hoenig J, Goldberg RA, Baylis HI, Morrow D. The endoscopic forehead lift. Ophthal Plast Reconstr Surg 1998;14(2):107–118.

216 A.D. Morton

iii)May keep a warm water thermos to holster the endoscope

(1)Decrease fogging by keeping scope closer to patient’s body temp

5)Setup essentials

a)Know your electronics and specifics of camera connections

b)Sterilization

i)Cold (e.g., Steris) easiest on camera and light cable

ii)Can use sterile wrap (e.g., condom over cable) but makes it harder to manipulate

c)Drying and defogging

i)Ensure that all interfaces are dry—moisture in any of these areas will degrade image

(1)Camera coupler to scope eyepiece

(1)Camera cable to coupler

d)Confirm signal

i)Ideally before injecting or sedating patient

ii)The time to realize that the camera is not working is BEFORE you begin the procedure

6)Trouble-shooting tips

a)Picture not centered

i)Ensure that endoscope is seated and centered in the camera coupling ring

ii)Some monitors have an image magnification switch that may limit your peripheral viewing

b)No picture on monitor

i)Check for monitor power

ii)Check for cable from camera video out to monitor video in

c)Picture too dark

i)Auto iris on camera may be tricked by heme in the optical cavity

ii)Turn off and adjust light source power to appropriate level

d)Tissue color balance incorrect

i)Repeat white balance

e)Picture blurry or foggy

i)Check focus on camera coupler hand piece

ii)Blood on tip of endoscope

(1)Flush through irrigating port on the cannula

(1)Remove scope, wipe tip, and apply antifog

iii)Fluid has leaked into one of the other optical interfaces— check and clean:

(1)Camera coupler to scope eyepiece

(1) Camera cable to coupler

218 A.D. Morton

iii) Defog

(1)Helpful to keep the scope warm in a waterbath

(2)Antifogging solutions (FRED) available in the OR

(a)Can be applied to the tip of the scope

(b)Work well without the extra hassle of the water bath

b)Camera

i)Coupler

(1)Attaches to the viewing end of scope

(2)Converts image to a signal that is processed by the camera box

ii)One vs. three chip systems

(1)Cost vs. clarity

(2)Most one-chip cameras provide more than adequate clarity and definition

iii)Focusing

(1)With system connected, place tip 1 cm from suture packet or other object with small lettering

(2)Adjust knob on coupler device

iv)White balance

(1)Flat white object is placed in front of endoscope, and when activated camera will auto adjust to provide most realistic color balance

v)Auto iris

(1)Most cameras have selection to allow camera to determine appropriate amount of illumination

(2)In some settings manual adjustment is helpful

(a)In a bloody field auto iris will underestimate the illumination needs

c)Light source

i)Xenon is the preferred option

ii)Spend the money, skimp elsewhere if necessary

d)Monitor

i)High-resolution 13to 20-inch model preferable

ii)Although not essential, two monitors allow for ease of viewing from different surgical positions

e)Recording source

i)Optional

ii)Vhs or still recorder

2)Hand instruments

a)Essential

i)Periosteal elevator/dissector (central pocket)

(1)Straight

(2)Curved

ii)Temporal dissector

(1)Oval, dissects sideways as well as forward

(2)Separates superficial temporal fascia from superficial layer of the deep temporal fascia

iii)Periosteal spreader

(1)Upturned tip useful to spread periosteum after opening of arcus marginalis along superior and lateral orbital rim

Chapter 68 Endoscopic Forehead Rejuvenation: Equipment and Setup 219

iv)Endoscopic scissors

(1)Right-handed surgeon can get by with only the left going

(2)Nice to have both right and left though

(3)Cutting periosteum

(4)Transecting corrugators and procerus

v)Endoscopic grasping forceps

(1)Right-handed surgeon can get by with only the left going

(2)Nice to have both right and left though

(3)Dissecting out the corrugators from the supratrochlear nerve and vessel

(4)Stripping the corrugator and procerus

(5)Grabbing bleeding vessels to transmit externally applied cautery (instrument is insulated)

vi)Nerve hook

(1)Come as right and left going

(2)Useful to dissect out the supraorbital and supratrochlear neurovascular bundles

(3)Also can be used to strip out the procerus

b)Nice to have instruments

3)Cautery

a)External monopolar

i)Applied to insulated endo instruments

ii) Shielded frasier suction

(1)Red rubber covering

b)Endoscopic suction coagulators

c)Ellman RF suction coagulators

4)Boney fixation

a)Drill motor or hand drill

b)Anchors

i)Flush mount

c)Screws

i)Permanent

ii)Bioabsorbable

d)Posts

e)Bone tunnel

i)Metal template

f)K wire

g)Tissue glue

5)Miscellaneous

a)Skin hooks

i)Assist in introducing the endoscope

(1)Avoids blood on tip

ii)Temporal incision

(1)Elevates the superficial layers away from the deep

(2)Minimizes risk of dissection in the wrong plane

b)Free needles

i)Straight or curved