“Laser in Orthopedic Surgery”(Part-3)

Interaction and effects of laser (UV-IR) radiation on biological tissue and its uses in Orthopedic Surgery.

Presented by-Dr. Md Nazrul Islam.Assistant Registrar, Orthopedic and traumatology Department, Shaheed Suhrawardy Hospital, Dhaka-1207.

Laser : Alternative/ Adjuventive

Over 2,500 scientific studies in the National Library of Medicine have identified the many benefits of laser therapy as an alterative to surgical intervention for pain.  

Laser therapy does not require the use of drugs or invasive treatment; there are fewer side effects and risks, and it is quick, painless, and convenient.

It can be adjuventive to other modalities of treatment like- medication, surgery or other therapeutic approach.

LaserInteraction with Biological Tissues:

Types of laser, based on Effectiveness:

a. Biostimulative Laserb. Bioinhibiting Laser.

a. Biostimulative Laser: Laser is biostimulative effect on bioligical tissues, when it is used in a targeted tissue with specific wavelength.

Different biological tissue is responsive to different wavelength.

b. Bioinhibiting Laser: Laser has bioinhibitory effect when it is used with inappropriate

wavelength, that means laser can be harmful to biological tissue when it is used with an inappropriate wavelength.

Types of laser, based on power: a. Low power Laser b. High power Laser

Low power Laser: It has long wavelength, anabolic effects, and it promote rapid reduction of pain, accelerates healing time/ growth and reduce repair stage of healing: on the other hand don't give of heat use photo energy.

High power laser: they have shorter wavelengths which have catabolic effects that can deliberately destroy tissue in cauterizing and surgical applications, are used to through tissue and give off heat.

Interaction of laser on biologic tissues:

Scattering Penetration Absorption

Electromagnetic radiation in the UV-IR spectral range propagates into biologic tissues until it is either scattered or absorbed.

Interaction of laser with biologic tissue:

Interaction of laser with biologic tissue:

Interaction of laser on biologic tissues:

Interaction of laser on biologic tissues:

Scattering of laser into biologic tissue:

Scattering occurs at the boundaries between

regions having different optical refractive indices because of inhomogeniusness that is-

a. Water b. Biomolecule (Protein, lipid etc.) c. Pigments in the tissue.

Penetration of laser into biologic tissue:

Penetration of laser in the

biological tissues is supposed to be occurred in an exponential decrease (Bears Law) if there had been no scattering or absorption.

Absorption of laser into biologic tissue:

Laser absorption in biological tissues ( In IR-UV region of medical interest)

predominantly depends on wavelength.

The absorption of laser is highest in water molecule.

Protein, Pigments and Melanin has different absorption coefficient depending their molecular structure.

Absorption of laser into biologic tissue:

Absorption of laser into biologic tissue:

Absorption of laser into biologic tissue:

Absorbed energy from laser releases from water/ biomolecule by-

Fluorescence Resonant electronic energy

transfer and Thermal vibration.

Application of Fluorescence effect of laser:

Laser-induced fluorescence (LIF) is

a spectroscopic method used for studying structure of molecules, detection of selective species and flow visualization and measurement.

Resonant electronic energy transfer.

Resonance energy transfer (RET) or electronic energy transfer (EET), is a mechanism describing energy transfer between two chromospheres.

FRET has been applied in an experimental method for the detection of phosgene.

Application of absorption effects of laser:

Thermal Heating of tissues has two effects -

Coagulation/cauterizing of tissues, Tissue vaporization for incising or

excising.

Ionizing Ablation of the molecules in the target tissue.

This form of photodisruption is used primarily in ophthalmic / Orthopedic practice.

Phototherapy Photochemical effects include photoablation, photodynamic therapy (necrosis of tumors in cancer), and photoradiation to enhance wound healing.

Stages of tissue healing by laser therapy:

Haemostasis; the arrest of bleeding by involving the physiological processes of blood coagulation and contraction of blood vessels. Haemostasis lasts several minutes.

Inflammatory phase; triggers neutrophils and macrophage migration into the wound. This phase lasts several days.

Stages of tissue healing by laser therapy: (Continues)

Granulation; the formation of a multicellular mass of tissue which can last up to three weeks.

Re-epithelization; basement proteins reappear in a very ordered sequence from the wound inward in a zipper like-fashion closing the epidermal defect.

Wound contraction and tissue remodeling; growth factors and other peptides provide stimuli for wound contraction.

Laser application in Tissues:

General view-

Laser Therapy promotes:

Improved circulation Improved nerve function Accelerated tissue repair Increased mobility and muscle

function

Laser Therapy helps:

Reduce inflammation Decrease swelling Heal soft tissue injuries Diminish or eliminate acute pain Reduce chronic pain and discomfort

Laser Therapy successfully treats-

Acute and chronic pain Arthritis (osteoarthritis and rheumatoid

arthritis) Soft tissue injuries, including sprains and

strains Tendonitis and bursitis Muscle spasm and tension Vertebral disc conditions Sciatica, neuralgia, fibromyalgia Post operative orthopedic, implants,

fractures Swelling and edema

Post-Operative Healing:

Clinical studies have shown that laser therapy is

especially beneficial for post-op patients. It works to accelerate tissue repair and cell growth, heal wounds faster, reduce the formation of scar tissue, reduce swelling and pain, improve vascular and metabolic activity and boosts the function of the immune system.

The energy produced by the laser stimulates the production of collagen and ATP (a DNA-related enzyme that serves as a source of energy to cells), promotes blood circulation, and stimulates the regeneration of nerves. The non-invasive treatment speeds recovery and accelerates bone and wound healing, which means significantly less down time for the patient.

Advantages of laser surgery vs. traditional surgery?

Most laser surgeries can be performed on an outpatient basis.

Very small / precise incision. No damage to surrounding areas Less bleeding /"bloodless surgery," , and less

swelling. Less time consuming procedure. Lower rate of local infections. Reduce post-operative pain. Reduce post operative recovery period.

Disadvantages of laser surgery vs. traditional surgery?

Cost. Eye hazards. Imprecisely aimed lasers can burn or destroy

healthy tissue. Needs special training/ arrangement. Cardiopulmonary resuscitation (CPR)

arrangement is recommended to avoid/ manage electrical incidence.

Risks:

Like traditional surgery, laser Surgery can be complicated by:

Hemorrhage Infection Perforation (piercing) of an organ

or tissue.

Diagrammatic comparison graph to show muscle healing by laser therapy, to non-laser treated patients, assessing

creatinine kinase level.

Laser application in Orthopedics:

Application of laser in orthopedic surgery:

Musculoskeletal Wound Healing Nerve Regeneration a. To reduce pain.b. To reduce inflammation c. Increased tissue tensile strengthd. Increased collagen productione. To enhance and reduce healing

time.f. In surgical procedure.

Application of laser in orthopedic surgery: Pain Management:

• Fibromyalgia • Myofascial pain • Cervical neck pain • Low back pain • Joint pain • Trigeminal neuralgia

Application of laser in orthopedic surgery: Inflammatory Conditions:

• Rheumatoid Arthritis • Carpal Tunnel Syndrome • Tendonitis • Plantar fasciitis • Bursitis

Application of laser in orthopedic surgery: Connective Tissue Injury / Disorders:

• Sprains • Strains • Tendonitis • Tendon ruptures

Application of laser in orthopedic surgery: Joint Injuries / Disorders:

• TMJ disorders • Osteoarthritis • Dislocations • Ligament injury

Application of laser in orthopedic surgery: Muscle Injuries / Disorders-

• Muscle bruises, contusions • Muscle ruptures • Muscle trigger points.

Application of laser in orthopedic surgery: Neurological injury / disorders-

• Prolapsed disk • Ruptured disk • Crush injuries • Neuritis • Trigeminal neuralgia • Tinnitus

Application of laser in orthopedic surgery: Skin injuries / conditions-

• Surgical incisions • Skin ulcers • Burns • Skin grafts

Application of laser in orthopedic surgery: Diagnostic-

Arthroscopy. Bony tissue Biopsy. Angioplasty Tumor imaging and visualization

Selective caries removalBlood flow cytometryLaser induced fluorescence imagingPhotoacoustic imagingTMR

Application of laser in OrthopedicSurgery:

Therapeutic

Physiotherapy

Degenerative Conditions:Rheumatoid Arthritis Osteoarthritis

Soft Tissue Injuries:Arthritis Pain• Tendinitis• Tennis Elbow• Acute Pain • Chronic Pain • Wound Healing• Carpal Tunnel• Strains/ Sprains• Frozen Shoulder• Plantar Fasciitis• Fibromyalgia • Knee Pain• Neck & Back Pain• Whiplash

Therapeutic Therapeutic nonoperative-nonoperative-

Application of laser in OrthopedicSurgery: Therapeutic

Therapeutic operative-

Reconstructive surgery: knee Spine surgery: PLDD Removal of soft tissue mass. Amputation: Biopsy: Bone/Soft tissue.

Important parameters

Laser parameters : Wavelength, Power density, exposure time, pulse duration, focused spot size, repetition rate.

Optical properties of the tissue :absorption and scattering coefficients

Thermal properties of the tissue: thermal capacity and thermal conductivity.

See you next day with- “Laser in Orthopedic Surgery”

(Part-4)Laser on Hard Tissue

Thankseveryone for patience,

Bye.