USE OF IMPLANT IN SURGERY

DR BASHIR YUNUSASURGERY RESIDENT AKTH

26/01/16

OUTLINE• INTRODUCTION • CLASSIFICATION• PRINCIPLES OF USAGE• COMPLICATIONS• USES OF IMPLANTS • EMERGING TRENDS• CONCLUSION• REFERENCES

INTRODUCTION• An implant is a surgically inserted foreign material or device to

replace a biological missing structure, support damage structure or enhance an existing structure.

• An implant is a foreign material or device that is inserted, embeded or fixed into a living tissue for functional or cosmetic reasons.

EPIDEMIOLOGY • Use of implant is on the rise world wide attributed to cosmetic

augmentations, rising disease incidence and reduce the need for transplant. Estimated 20-25million US patients have had a medical device implanted.• In African sub-regions due to development of specialties.

QUALITY OF AN IDEAL IMPLANT An ideal implant should:• Not cause inflammatory or foreign body response• Non-allergenic• Non-carcinogenic• Resistant to strain• Fabricated into desired form• Sterilizable• Radio-opaque • Non yet to be found

INDICATIONS • Reconstruction e.g breast reconstruction after mastectomy, • Augmentation e.g breast augmentation mammoplasty, dental implant

bone augmentation. • Fixation & stabilization e.g fractures, dentures • Replacement e.g missing structure, deformed or painful joint.

CLASSIFICATION • US classification The US Food and Drug Administration(FDA) classify medical devices base on the risk to the user

• Class 1- least amount of risk, rquires least amount of control e.g arm sling, hand held surgical instrument• Class 2- need more regulation than class 1. are required to undergo specific requirement before FDA

approval. E.g X-rays, monitors• Class 3- requires most regulatory control, since device sustain or support life – medical implants

• Temporary or permanent• Soft or hard• Biodegradable & nonbiodegradable• Synthetic or biological • Base on the chemical properties of the implant; metals, calcium ceramics, biodegradable,

polymers

BASE ON THE CHEMICAL PROPERTIES OF IMPLANT• METALS • Are used mainly in orthopedics, craniomaxillofacial and hand

surgeries. Eg Kirschner wires, cranial plates, artificial joints.• Currently used metals;• Titanium, stainless steel, valium,gold.

• Properties; biocompatible, strength, resistance to corrossives, radio-opaque.• Titanium is light weight 6 times stronger than compact bone, modulus

of elasticity is 5 times greater than compact bone. Most commonly used is commercially pure titanium or titanium-aluminuim-vanadium

CALCIUM CERAMICS• Hydroxyl apartite• Tricalcium phosphate• Tetra calcium cement (hydroxylapatite cement)

BIODEGRADABLE MATERIALS• Collagen• fibrel

POLYMERS• Silicone• Polyurethrane• Polymethyl metacrylate• Polyester (Dacron, mersilene)• Poly ethylene• Polypropylene• Cyanoacrylate• Polytetrafluroethylene PTFE

PRINCIPLES • PRE-OPERATIVE• Patient must meet indications• Perioperative prep & mgt – All physiological derangement is corrected• Informed consent• Selection

• Depends on the specific requirement for its use• Site & strength of the tissue• Appropriate size • Availability• Affordability• Expertise

• INTRA-OP• Adequate anaethesia• Strict aseptic techniques• Antibiotic prophylaxis• Adequate incision• Adequate soft tissue cover• Must be accessible for removal if necessary• For injectable one should be cautious not to inject in vessels• Implant be of appropriate size and shape to avoid sharp curves and edges

Post-op• Wound• X-ray• Follow• Complications• Failure

COMPLICATIONS • Local

• FAILURE – inadequate for function expected. or failure to produce a satisfactory result • • Causes of such failure can be grouped into four categories:• surgical• material; Fatigue failure, Corrosion, Implant wear, Loosening, Breakage• Idiosyncratic• patient compliance

• Extrusion • Infection• Tissue reaction • migration• Hematoma • Seroma

• Systemic• Allergies• Carcinogenesis

USES OF IMPLANT

ORTHOPAEDIC SURGERY• Nails• Wires• Screws• Plates and screws• Bone cements• Joint prosthesis

Plates

screw• Cortical • Cancellous • Locking

Kirschner’s wire

NAILS • Intramedullary nails

JOINT REPLACEMENT

GENERAL SURGERY• Polypropylene mesh implants in hernia repairs• Palliative stents of malignant obstructive lesions (endoluminal

prosthesis)• Bile duct drainage (latex T-tube)

PLASTIC SURGERY• Breast implants using silicone • Malar and submalar implants using subcut materials like ePTFE• Body contouring like buttock enhancement using silicone• Use of gold as upper eyelid weight.

CARDIOVASCULAR SURGERY• Heart valve replacement• Drug eluting biodegradable coated stents in coronary vascular disease• Pacemakers• Septal defect repair using nylon patches• Vascular stents using ePTFE in aneurysm repairs

PACEMAKER

UROLOGY• Ureteric stent• Urethral stents• Penile implants using inflatable silastic tubes in mgt of ED• Penile enlargement implants• Testicular implants

Ureteric stent

Penile implant

NEUROSURGERY• Ventricular shunts using silastic tubes in hydrocephalus• Excimer laser non occlusive anastomosis (ELANA) in cerebral vascular

bypass using laser catheter.

ENT SURGERY• Nasal reconstruction using silicone, tricalcium phosphate cements• Palatal implants using inserts (made from silicone, polyester ) in soft

palate in surgical management of snoring and obstructive sleep apnoea• Cochlear implants in sensorineural deafness

Cochlear implants

OPHTHALMOLOGY

• Glaucoma drainage device made from silicone (silicone tube and plate)• Lens implants• Globe implants

Dental surgery Endo-osteal SubperiostealTransosteal Intramucosal

MESH• Synthetic

• High tensile strength • Unsuitable for intraperitoneal placement• Tissue reaction, stiffness, fibrosis • E.g polypropylene, PTFE, ePTFE, polysters.

• Biological • Collagen base- human or porcine• use intra or extra-peritoneal • Can be used to contaminated or infected surgical field • Overcome the problems of chronic inflammation and foreign body reaction, stiffness and fibrosis associated synthetic mesh.

• Composite • Dual coated,- visceral and parietal side. Visceral side repels tissue ingrowth and decrease adhesion. Synthetic parietal side

promotes strong repair

• Microporous <10um• Allows bacteria but prevent macrophage passage, cannot clear infection• Granuloma more likely to form leading to stiffness of scar.• Multifilament

• Macroporous > 75um• Allow infiltration by macrophage, blood vessels, fibroblast and collagen • More flexible becomes of avoidance of granuloma.• monofilament

BREAST IMPLANT

• Subcutaneous, subglandular, submuscular • Implant in submuscular plane is better whenever muscle is not removed

during surgery.(better soft tissue covering and hide irregular contour)• If muscle is removed as in radical mastectomy, then subcutaneous

implant is placed.• Silicon gel implants• Saline implant• complications

• Pain, exposure of implant and rupture• Displacement, extrusion• Infection• Capsular contraction• Rippling

HEART VALVES • Mechanical; manufatuerd from varieties of materials like alloys, silicon,

rubber etc. donot resemble native valve. Risk of thrombo-embolism. Requires anticoagulant. • Tilting disc valves • Bileaflet valve

• Biological; they are made from human or animal tissue. Have good hemodynamic performance, the thromboembolic risk is small. Can be used without anticoagulant. But short lived(5-10years), hence requires 2nd operation. Especially in young patient • Allograft • Glutaraldehyde-treated porcine(pig) valves • Glutaraldehyde-treated pericardial valves

• Choice of valve

EMERGING TREND • Biodegradable fixation• Minimally invasive • Saline filled breast implants • Implants incorporated into bone growth

CONCLUSIONImplants are invaluable in surgical therapy especially in replacing damage body part. Availability, affordability, and expertise is paramount for a successful therapy. They are not without side-effects. The world still awaits emergence of an ideal implant.

REFERENCES• M.A.R.Al-Fallouji:Postgraduate surgery,2nd Edition.• Apley’s system of orthopaedics Eight Edition• Bailey and Love’s “Short Practice of Surgery” 26th edition CRC press Taylor and Francis

group. 2013• E.A Badoe et al, “Principles and Practice of surgery including pathology in the tropics”

4th edition, Assembly of God Literature Center ltd, 2009• A.S .Breitbart & V.J.Ablaza:Dept of plastic & Reconstructive surgery,New York University

Medical Center.• Deporah, Shatin, et al; “Data base for studying the epidemiology of implanted medical

devices” The Bionic Human pp115-132 • Van Eck, Chen AF et al; “the classification of implants” J long term Eff Med Implant 2009;

19(3) 185-93

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