Lasers in surgery aditya kalyan
History Maiman ,1960, Ruby 1962, Leon Goldman . Dr.Goldmans experiment was the first use of lasers in
the medical history Early 1980s, John Parrish and Rox Anderson -
Selective Photo Thermolysis - Risk of scarring & damage to normal tissue
Biological activity of laser light is due to Absorption phenomenon by chromophores
Photons energy of laser light is transferred to blood, tissues or bone in the form of heat.
Laser can transfer photon energy to chemical bond energy of the molecules in human body, like DNA.
There are generally three interaction mechanisms involved.
1) Photocoagulation2) Photovaporization3) Photoablation Thermal effects depend on Energy density.
Photocoagulation A Laser heating of tissues above 50 oC & below
100oC induces disordering of proteins and other bio-molecules
Shrink in mass – water expelled Heated region loses its mechanical integrity Cells in the photocoagulated region die and a region
of dead tissue called photocoagulation burn develops
Applications Destroy tumors Treating Retinal disorders caused by diabetes Hemostatic laser surgery - bloodless incision,
excision: Blood vessel subjected to photocoagulation
develops a pinched point due to shrinkage of proteins in the vessel’s wall, helps seal off the flow.
Photovaporisation With very high power densities,lasers will quickly
heat the tissues to above 100o C water in tissues boils and evaporates. Since 70% of the body tissue is water, the boiling
change the tissue into a gas. Results in complete removal of the tissue. Hemostatic incision or excision, Skin
Rejuvenation, Resurfacing.
Photoablation When using high power lasers of ultraviolet
wavelength, chemical bonds are broken,without causing local heating.
Thermal component is relatively small and zone of thermal interaction is limited
Results in clean cut incision
Selective absorption A given color of light is strongly absorbed by one
type of tissue,while transmitted by another. Lasers’ pure color is responsible. Oxyhemoglobin in blood: Absorption of
UltraViolet, blue and green light Melanin a pigment in skin, hair, moles etc:
Absorption of visible and near Infrared light Water in tissues: Transparent to visible light
Selective absorption : Absorbing component being Melanin pigment in hair and follicle, it is best worked with a Red light ruby laser. White hair can not be treated with any laser due to the lack of absorbing component
Excimer Laser Excited Dimer Noble gas halide Photoablative effect-Cool Laser Ophthalmologic sugeries like LASIK, PRK.
Argon Laser Tissue depth penetration only 1mm-
Superficial coagulation Precise cutting with minimal damage to
adjacent tissue Absorbed best in Red,Black tissue Retinal photocoagulation Arterial Recanalisation
Dye Laser Pulsed Lasers Organic Dyes like Kiton Red,Rhodamine. Tunable Lasers Dye can be replaced-Different wavelengths
with same laser Port-wine stains,Pigmented lesions
Co2 Lasers Most effective Laser Scalpel 0.1mm zone of Histologic Necrosis Cutting & Vapourising Instrument Seals lymphatics as it cuts through,decreasing
spread of malignant cells Loss of tissues through Evaporisation Skin resufacing- Laser Facelifts
Nd:YAG Laser Most widely used in medical field High penetration capacity of >5mm Photocaogulation Endoscopic Laser To arrest bleeding GI varices Debulking GIT & Pulmonary tumours Coagulates Bladder tumour
Ho:YAG Treats tissue in a liquid-filled environment
(e.g., saline, blood) Endoscopic Laser Orthopaedic Laser used in Arthoscopy
Er:YAG Shallow penetration Extreme surgical precision
Diode Laser Semiconductor devices that emit Laser light as
electric current passes through them Tunable laser Fiberoptic delivery system Photocoagulation for general surgery Hair removal
Applications Vascular Malformations of GIT Diffuse gastric antral vascular ectasia Colonic vascular malformation Argon & Nd:YAG lasers Photocoagulation therapy 80% success rate in contolling recurrent
blood loss & subsequent transfusions
Upper GIT Carcinoma Early Gastric cancer Endoscopic laser therapy (Nd:YAG) can
eliminate cancers completely 3 Requirments:Lesion <4cm with no
lymphnode metastasis,Followup,operator Advanced carcinoma it is a palliative
procedure to relieve obstruction,dysphagia or bleeding
Destroy neoplastic tissues & recanalise lumen
Relief of dysphagia 92%,perforation 10% Outpatient basis
Colorectal Cancer Laser therapy with Nd:YAG indicated in Patients with Metastatic or unresectable
local disease In Obstruction,Haemorrhage for Palliative
therapy
Liver Fibrotic Liver Resection Controlled resection of liver without
bloodloss possible Nd:YAG Laser with tissue contact tip Insitu ablation of Intrahepatic
malignancies (metastases) Palliation in HCC
Bile duct stones Laser Lithotripsy Coumarin pulsed dye laser For Bileduct stones that can’t be extracted
easily Break stones into small fragments which
pass spontaneously Light energy to Acoustic energy
Haemorrhoidectomy CO2 or Nd:YAG Laser with contact tip Like scalpel precisely cut through pile mass, melt them & subsequent sloughing
Neurosurgery-Nd:YAG AV malformations Highly Vascular Meningiomas Lesions at inoperable sites like Base of
skull,midbrain,floor of fourth ventricle
Laparoscopic Surgery
CO2 Laser Argon laser & Nd:YAG with contact tips Endometriosis Cholecystectomy (KTP/Nd:YAG) Lymphadenectomy (KTP) Posterior trunca vagotomy in peptic ulcer disease
Vascular Applications Laser Endarterectomy – Argon laser Smart Laser- Reflective Fluorescent spectral data Combination of Helium laser for fluorescence
excitation & Holmium laser for plaque ablation are tried
Laser Angioplasty – Co2,Argon,Nd:YAG
Laser angioplasty.avi
Laser assisted balloon angioplasty done in localised lesions of common iliac & superficial femoral artery
Prosthetic graft stenosis – Argon laser Angioplasty
Urology Renal stones - Laser lithotripsy Coumarin-based pulsed dye laser Light energy is delivered through Flexible quartz
fibers, directed Endoscopically onto a calculus Mechanism of action occurs via plasma
formation between the fiber tip and the calculus, which develops an acoustic shockwave that disrupts the stone along fracture lines
Endoscopic extraction
BPH Photovaporisation - Tissue water is vaporized
resulting in an instantaneous debulking of prostatic tissue.
KTP or Greenlight is commonly used for its vaporization effects on prostate tissue.
Less bleeding and fluid absorption than standard TURP
Lack of tissue obtained for postoperative pathological analysis
Urothelial stricture Disease
Nd:YAG, KTP, and Ho:YAG lasers have all been used experimentally to vaporize fibrous strictures
Urothelial malignancies Transitional cell carcinoma of bladder, ureter, and renal pelvis
Skin lesions CO2 Lasers - Condyloma acuminata, Haemangioma
of external genetalia,early penile carcinoma.
Advantages Bloodless field Excellent Haemostasis Excellent Healing Allow precise Microsurgery Less postoperative pain & oedema Lower infection rate Outpatient procedure
Drapes, Towels – Wet Fire Extinguisher, Water/Saline Water/Saline saturated fire retardant materials Laser safety officer- Hazard zone, Minimal access
Disadvantages Atmospheric contamination: Laser Plume Mutagenic,Teratogenic or vector for viral infection. Interstitial pneumonia Bronchiolitis Reduced mucociliary clearance, inflammation
Misdirection of laser energy perforation of viscous or large blood vessels Eye damage Skin damage Fire and explosion: Gas embolism: laparoscopic or Hysteroscopic laser surgery