Light Amplification by the Stimulation of Radiation (LASER

1
Light Amplification by the Stimulation of
Radiation (LASER)

• James Ridgway, MD
• 3/22/07

2
Patient History

• Patient is a 18 week old male presenting to
  pediatrics with a two week history of noisy
  breathing that is worse with crying. This was
  noted when the child was with mother at work (she
  works at a daycare facility). This has worsened
  considerably over the last 5 days with difficulty
  in feeding and has created a considerable amount
  of parental concern. Pediatrics has consulted
  you as med-nebs have had little effect over the
  last 4 hours.

3
Patient History

• PMH Uneventful full term delivery. Child has
  had unremarkable history until current condition.
• PSH None
• Medications None
• Allergies NKDA
• SH Lives with parents, immunizations UTD
• FH Grandparents with DM, HTN

4
Physical Examination

• General Alert, but with nasal flaring and
  retractions. biphasic stridor
• Ears TM C/I/M AU
• Nose No evidence of polyp, septal perforation or
  mass
• OC/OP 2 tonsils, no cleft or lesion
• Neck Soft, supple and without mass or LAD
• Face Full facial motion and symmetry
• On examination of the left abdomen there is a
  red, slightly raised lesion that has evolved
  rapidly over the last week

5

• Vascular pulmonary artery sling, double aortic
  arch, anomalous innominate artery,
  retroesophageal right subclavian artery,
  hemangioma.
• Infection bacterial tracheitis,
  laryngotracheobronchitis, abscess
  (retropharyngeal/ parapharyngeal/ peritonsillar),
  croup, epiglottitis, tuberculosis
• Trauma intubation trauma, foreign body,
  laryngeal fracture, caustic and thermal burns
• Autoimmune ?
• Metabolic hypothyroidism
• Iatrogenic/idiopathic vocal cord paralysis
  (unilateral or bilateral), localized malacia
  secondary to a tracheostomy or TEF repair,
  subglottic stenosis, arytenoid dislocation, trach
  obstruction, gastroesophageal reflux.
• Neoplasia cystic hygroma, rhabdomyoma,
  neuroblastoma, bronchogenic cyst, teratoma,
  thymus
• Congenital laryngomalacia, laryngotracheal
  stenosis, posterior laryngeal cleft, vallecular
  cyst, laryngeal cysts, laryngeal webs,
  laryngocele, arytenoid fixation, complete
  cartilage rings, tracheobronchomalacia, choanal
  atresia/stenosis, macroglossia, micrognathia,
  Arnold-Chiari malformation

6
Hemangioma

• A wait-and-see policy was recommended before
  laser development
• Functional or structural complications should be
  treated
• Batta et al. - first prospective and randomized
  controlled study in uncomplicated hemangiomas in
  121 children
• FPDL (585nm, 0.45ms, 35mm, 67.5 J/cm2)
• 1 year 30 in treatment group had resolved, 5
  in control
• Residual lesions in 42 of treated, 44 of
  control
• Hypopigmentations more frequent in treatment
  group (45 vs. 15) and also slightly atrophic
  scars (28 v. 8)
• Control group hemangiomas increased by 160
  compared to 61 in treatment group
• Tanaka et al. supporting same level of
  intervention

7
Subglottic Hemangioma

• Sie et al. with 10 year experience with CO2 laser
  in SGH
• Serial procedures and 20 rate of post-treatment
  subglottic stenosis
• Madgy et al. reviewed six cases of SGH managed
  with the KTP laser
• Steroids after surgery
• End point was to achieve 60 to 70 airway patency
• 3 with mild post-procedural SGS
• Barlow et al. - spastic diplegia in 20 of 26
  children less than 2 years of age treated with
  IFN
• Life threatening
• Hemangiomas respond to steroids in 30 to 60 of
  cases IFN administered in non-responders

8
Treatment

• Indicators for intervention
• Compromised airway
• Deviation of visual axis
• Oral/digestive tract obstruction
• Bilateral auditory obstruction
• Relative bleeding, ulceration and potential for
  significant facial disfigurements

9
Laser History

• 1917 Einstein first discusses stimulated
  emissions
• 1954 Townes Gordon maser
• 1958 Townes Schawlow (Bell Laboratories)
  publishes first theoretic calculations of then
  titled laser
• 1960 Maimen (Hughes Aircraft) develops first
  laser (ruby with 694 nm wavelength)
• 1961 Neodymium-doped (Nd) glass laser
• 1964 NdYAG and argon ion (Ar)
• 1965 CO2 laser
• 1968 Polanyi develops articulating arm for CO2
  laser
• Later works with Jako on the ablation of vocal
  fold papillomatosis

10
The Laser

• Three essential elements
• Lasing medium
• Excitation source
• Two mirrors to provide optical feedback

11
The Laser

• Resonant Cavity
• Spontaneous emission
• Stimulated emission
• Population inversion
• Laser output

12
Laser Properties

• Monochromatic
• Coherent
• Collimated
• High energy density (Power density)
• Irradiance intensity / area watts / cm2
• Fluence (intensity X time) / area
• watts X seconds / cm2 J /
  cm2

13
Laser Delivery

• Handheld
• Articulating arms
• Optical fiber
• Patient-to-laser

14
Beam Characteristics

• Beam waist (d)
• d 2fl / D (f focal length, D diameter)
• Depth of focus (Df)
• Df p X d2 /2l

15
Temporal Profiles

• Continuous or Pulsed
• Mechanical shutter (1ms 1s)
• Flash-lamp-pumped lasers (1ms 1ms)
• Q-switched (10ns - 10ms)

16
Light and Tissue Interactions

• Absorption
• Scattering
• Reflection
• Transmission

17
Laser Materials/Properties

• Infrared light primarily absorbed by water
• Visible and UV light are absorbed by hemoglobin
  and melanin
• As wavelength becomes shorter scatter begins to
  dominate the penetration of light

18
Tissue Ablation

• 10 C 45 C Conformation change of proteins
• 50 C Reduction of enzyme activity
• 60 C Denaturation
• 100 C Water vaporizes
• Thermal damage

19
CO2 Laser

• 10,600 nm wavelength
• Water is target chromophore
• Aiming helium-neon (HeNe) beam
• Highest power continuous-wave laser
• Cutting or ablating tool
• Focus to 200 mm
• Seals blood vessels less than 0.5 mm
• Pulsed to accommodate thermal relaxation time,
  less pain and less edema
• Pattern generators
• Work in distal airway in hands off fashion
• Used in majority of procedures except those
  requiring coagulation of larger vessels
• No current optical fiber to carry beam

20
Nd YAG Laser

• 1064 nm wavelength (neodymium-doped yttrium
  aluminum garnet )
• Aiming helium-neon (HeNe) beam
• Wavelength is between minimal absorption of
  water and a small amount of scatter
• Solid state laser
• Fiberoptic carrier
• Application
• Deeper penetration (up to 4 mm) for ablative
  therapy and hemostasis
• Preferentially absorbed by pigmented tissues
• Vascular malformations amenable to treatment
• Used in a multitude of pulmonary, urology and
  gastroenterology procedures
• Minimally invasive percutaneous laser disk
  decompression
• Limitations
• Greater scatter than CO2
• Deep thermal injury
• Risk for transmural injury

21
Argon Laser

• 488 - 514 nm wavelength (ion laser)
• Oxyhemoglobin is target chromophore
• Small spot size (0.1 1 mm) variable in size
  and intensity
• Flexible delivery system
• Applications
• Retina or middle ear surgery
• Facial spider veins
• Junctional nevi
• Cherry hemangioma
• Vascular birthmarks
• Limitations
• Also absorbed by epidermal and dermal tissues due
  to melanin
• Continuous mode of operation
• Higher prevalence of postoperative pigmentary
  alteration and fibrosis
• Pulsed Dye Laser (PDL) preferred for many roles
  Argon laser originally used (treatment of
  vascular lesions, including spider veins,
  strawberry birthmarks and port wine stains)

22
KTP Laser

• 532 nm wavelength (potassium-titanyl-phosphate)
• Frequency doubling
• Nd YAG laser passes through a KTP crystal
  emission is ½ its wavelength
• Oxyhemoglobin is primary chromophore
• Fiberoptic carrier
• Continuous wave (CW) mode to cut tissue
• Pulsed mode for vascular lesions
• Q-Switched mode for red/orange tattoo pigment
• Applications
• Granuloma excision of the respiratory tract
• Subglottic/tracheal stenosis
• Subglottic/supraglottic cyst excision
• Inferior turbinate reduction
• Nasal papilloma excision
• Nasopharyngeal stenosis
• Supraglottoplasty
• Laryngeal papilloma excision
• Middle ear surgery (Cholesteatoma excision,
  stapes surgery)
• Delivery

23
Laser Safety

• Education attendance at a "hands-on" laser
  surgery course that stresses safety precautions
  proven reduction of laser-related complications
• Development of protocol for safe laser use
  (credentials, continued education, ect.)
• Dedicated laser technician/ nurse/ engineer
• Team approach in fire prevention and anesthetic
  management
• Safest anesthetic gas mixture is 30 oxygen in
  helium Posting of Laser in use signs
• Laser specific endotracheal tube
• Eye protection (medical personnel patient)
• Saline moistened eye pads
• Skin protection saline-saturated surgical towels
• Smoke evacuation two separate suction set-ups
• Ebonized surgical instruments
• Placement of signs and additional eye protection
  outside operative room

24
While using the CO2 laser in the ablation of
laryngeal papillomatosis the ET tube catches
fire. What do you do?

• A stop inflammable anesthetics
• B remove ET tube
• C pour water down the ET tube
• D OCT
• Time to initiation of fire and burn through the
  lumen of ET tube
• 0.3 second for T-tube (silicone)
• 0.5 s for jet ventilation tube
• 0.8 s for PVC endotracheal tube
• 5 s for Xomed laser shield endotracheal tube
• Laser-Flex tracheal tube (stainless) and aluminum
  foil wrapped PVC endotracheal tube did not catch
  fire after 30 s of CO2 laser irradiation
• In short, the stainless endotracheal tube is the
  safest tube during CO2 laser surgery.

25
Patient presents with lesion of the tongue.
Which laser is the best choice?
26
Patient has a predominantly green tattoo that
they want to have removed. Which of the
following is the best answer?

• A. Frequency doubling
• B. Q-switched Nd YAG
• C. Q-switched alexandrite
• D. Q-bert

27
Ossicular Surgery

• CO2
• Pros absorbed by water, no deep penetration into
  the inner ear
• Cons invisible (requires separate aiming beam),
  alignment of mirrors can be problematic
• KTP, Argon
• Pros Aiming beam is attenuated, treatment beam
  can pass through fiberoptic cable
• Cons Requires pigment for absorption, can pass
  through clear fluids and potentially damage the
  inner ear

28
References

• Einstein, A. On the quantum theory of radiation.
  Physikal Zeitschr 1917 18121.
• Reinisch L. Laser physics and tissue
  interactions. Otolaryngol Clin North Am
  199629(6) 893912.
• Lai HC, et al. Fires of endotracheal tubes of
  three different materials during carbon dioxide
  laser surgery. Acta Anaesthesiol Sin. 2002
  Mar40(1)47-51.
• Batta K, Goodyear HM, Moss C, Williams HC, Hiller
  L, Waters R. Randomised controlled study of early
  pulsed dye laser treatment of uncomplicated
  childhood hemangiomas results of a 1-year
  analysis. Lancet 2002 360 521527.
• Ossoff RH  The co2 laser in otolaryngology-head
  and neck surgery a retrospective analysis of
  complications.   Laryngoscope  1983 931287.
• Abramson AL, DiLorenzo TP, Steinberg BM  Is
  papillomavirus detectable in the plume of
  laser-treated laryngeal papilloma?.   Arch
  Otolaryngol Head Neck Surg  1990 116604.
• Tanaka R, Miyasaka M, Taira H, Tanino R.
  Comparison of pulsed dye laser and wait and see
  policy in treatment of childhood hemangioma.
  Lasers Surg Med 2005 17 35.
• Barlow CF, Priebe CJ, Mulliken JB, et al.
  Spastic diplegia as a complication of interferon
  Alpha-2a treatment of hemangiomas of infancy. J
  Pediatr 1998, 132527530.
• Sie KC, McGill T, Healy GB Subglottic
  hemangioma ten years experience with the carbon
  dioxide laser. Ann Otol Rhinol Laryngol 1994,
  103167172.
• Madgy D, Ahsan SF, Kest D, Stein I The
  application of the Potassium-Titanyl- Phosphate
  (KTP) laser in the management of subglottic
  hemangioma. Arch Otolaryngol Head Neck Surg 2001,
  1274750.
• American National Standards Institute   American
  national standard for the safe use of lasers,
  Z136.1,   New York, American National Standards
  Institute, 1996.
• Shah H  Benign tumors of the tracheobronchial
  tree. Endoscopic characteristics and role of
  laser resection.   Chest  1995 1071744.
• Karamzadeh, AM, et al. Lasers in pediatric airway
  surgery current and future clinical
  applications. Lasers Surg Med. 200435(2)128-34.
  
• Strunk Jr CL, Quinn Jr FB  Stapedectomy surgery
  in residency KTP-532 laser versus argon laser.  
  Am J Otolaryngol  1993 14113.
• Cummings Otolaryngology Head Neck Surgery,
  4th ed. 2005 Mosby, Inc.
• Landthaler, M, Hohenleutner, U. Laser therapy of
  vascular lesions. Photodermatol Photoimmunol
  Photomed 2006 22 324332
• Brown, DH. The Versatile Contact NdYAG Laser in
  Head and Neck Surgery An in Vivo and Clinical
  Analysis. Laryngoscope 110 May 2000. 854-867.
• Pransky, SM, Canto, C. Management of subglottic
  hemangioma. Curr Opin Otolaryngol Head Neck Surg.
  2004 Dec12(6)509-12.