Lasers in surgery

about lasers used in medicine

1. Lasers in surgery aditya kalyan

2. LASER Light Amplification by Stimulated Emission of Radiation

3. 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

4. Common Components of Lasers

5. Production of Laser

6. Laser output 2 Modes Continuous mode (Watts) Pulsed mode (Joules) Output depends upon the Medium

7. Properties Collimation

8. Monochromacity Coherence

9. Effect of Laser on tissues

10. When a laser beam projected to tissue

11. 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 .

12. There are generally three interaction mechanisms involved. Photocoagulation Photovaporization Photoablation Thermal effects depend on Energy density.

13. Photocoagulation A Laser heating of tissues above 50 o C & below 100 o C 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

14. 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.

15. Photovaporisation With very high power densities,lasers will quickly heat the tissues to above 100 o 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, S kin Rejuvenation , Resurfacing .

16. 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

17. 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

18. 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

19. Excimer Laser Excited Dimer Noble gas halide Photoablative effect-Cool Laser Ophthalmologic sugeries like LASIK, PRK.

20. 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

21. 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

22. Co 2 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 E vaporisation Skin resufacing - Laser Facelifts

23. 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

24. 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

25. 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

26. KTP Laser Fiberoptic delivery system Cholecystectomy

27. 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

28. 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

29. Destroy neoplastic tissues & recanalise lumen Relief of dysphagia 92%,perforation 10% Outpatient basis

30. Colorectal Cancer Laser therapy with Nd:YAG indicated in Patients with Metastatic or unresectable local disease In Obstruction,Haemorrhage for Palliative therapy

31. 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

32. 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

33. Haemorrhoidectomy CO 2 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

34. 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

35. 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

36. Laser assisted balloon angioplasty done in localised lesions of common iliac & superficial femoral artery Prosthetic graft stenosis – Argon laser Angioplasty

37. 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

38. 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  

39.   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.

40. Advantages Bloodless field Excellent Haemostasis Excellent Healing Allow precise Microsurgery Less postoperative pain & oedema Lower infection rate Outpatient procedure

41. Precautions

42. Laser Plume High Filtration surgical masks Smoke Evacuation units

43. Drapes, Towels – Wet Fire Extinguisher, Water/Saline Water/Saline saturated fire retardant materials Laser safety officer- Hazard zone, Minimal access

44. Disadvantages Atmospheric contamination : Laser Plume Mutagenic,Teratogenic or vector for viral infection. Interstitial pneumonia Bronchiolitis Reduced mucociliary clearance, inflammation

45. 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

46. THANK YOU