Invasiveness of surgical procedures

An invasive procedure is one that penetrates or breaks the skin or enters a body cavity. Examples of invasive procedures include those that involve perforation, an incision, a catheterization, or other entry into the body. Surgery is a typical medical invasive procedure.

Non-invasive procedure
A medical procedure is strictly defined as non-invasive when no break in the skin is created and there is no contact with the mucosa, or skin break, or internal body cavity beyond a natural or artificial body orifice. For example, deep palpation and percussion is non-invasive but a rectal examination is invasive. Likewise, examination of the ear-drum or inside the nose or a wound dressing change all fall outside the strict definition of non-invasive procedure. There are many non-invasive procedures, ranging from simple observation, to specialised forms of surgery, such as radiosurgery.

For centuries, physicians have employed many simple non-invasive methods based on physical parameters in order to assess body function in health and disease (physical examination and inspection), such as pulse-taking, the auscultation of heart sounds and lung sounds (using the stethoscope), temperature examination (using thermometers), respiratory examination, peripheral vascular examination, oral examination, abdominal examination, external percussion and palpation, blood pressure measurement (using the sphygmomanometer), change in body volumes (using plethysmograph), audiometry, eye examination, and many others.

The discovery of the first modern non-invasive techniques based on physical methods, electrocardiography and X-rays, dates back to the end of the 19th century. Since then, non-invasive methods – which penetrate the body nonetheless, but by electromagnetic or particle radiation rather than a scalpel – have continuously enlarged the scope of medical technology. Non-invasive techniques commonly used for diagnosis and therapy include the following:

Diagnostic images

 * Bioluminescence imaging
 * Dermatoscopy
 * Diffuse optical tomography
 * Gamma camera and other scintillographical methods, such as Positron Emission Tomography (PET) and Single-Photon Emission Tomography (SPECT), using radioactive tracers in the body
 * Computed Tomography
 * Gene expression imaging
 * Infrared imaging of the body
 * Magnetic resonance elastography
 * Magnetic resonance imaging, using external magnetic fields
 * Magnetic resonance spectroscopy
 * Optical coherence tomography
 * Posturography
 * Radiography, fluoroscopy and computed tomography, using X-rays
 * Ultrasonography and echocardiography using ultrasound waves for imaging

A recent advance is the substitution of invasive medical tests, such as colonoscopy by computer-based 3D reconstructions, such as virtual colonoscopy.

Diagnostic signals



 * Electrocardiography (EKG)
 * Electroencephalography (EEG)
 * Electromyography (EMG)
 * Photoplethysmograph(PPG)
 * Electrical impedance tomography (EIT)
 * Electroneuronography (ENoG)
 * Electroretinography (ERG)
 * Electronystagmography (ENG)
 * Magnetoencephalography (MEG)
 * Evoked potentials, such as the visual evoked potentials (VEP) and the brain evoked response audiometry (BERA) tests
 * Body impedanciometry
 * Impedance phlebography
 * Nuclear magnetic resonance spectroscopy
 * Percutaneous light spectroscopy (such as in pulse oximetry and capnography)
 * Actigraphy
 * Breath tests, such as the urea breath test
 * Intelligent biomedical clothing
 * Non-invasive biomedical sensor s
 * Endoluminal capsule monitoring

Therapy

 * Radiation therapy and radiosurgery, procedures that use external atomic particles (protons, neutrons, photons, alpha particles, etc.) or teletherapy x-rays to destroy pathological tissue within the body (brachytherapy can be non-invasive, minimally invasive, or invasive)
 * Lithotripsy, a procedure that uses ultrasound shock waves to break urinary calculus
 * Defibrillation, a procedure to block heart fibrillation and start normal rhythm
 * Mechanical ventilation, such as the iron lung.
 * Transdermal patches, used to deliver drugs applied to the skin.
 * Biofeedback
 * CPAP (Continuous Positive Airway Pressure) used to treat sleep apnea
 * VPAP
 * BIPAP
 * Neurally Adjusted Ventilatory Assist
 * Biphasic Cuirass Ventilation (BCV, e.g. Hayek RTX)
 * Photodynamic therapy
 * Therapeutic ultrasound
 * Extracorporeal thermal ablation
 * Extracorporeal magnetic innervation
 * Photo-infrared pulsed bio-modulation
 * Transcranial magnetic stimulation

In some cases, non-invasive methods will not work for the intended purpose, so medical technology has developed minimally-invasive methods, such as hypodermic injection (using the syringe), endoscopy, percutaneous surgery, laparoscopic surgery, coronary catheterization, angioplasty, stereotactic surgery and many others. The benefits for the patient are self-evident.

Open surgery
Open surgery is any surgical technique where the incision is sufficient of itself to permit the surgical procedure to take place under the direct vision of the surgeon (although magnifying aids such as loupes or microscopes may play a role in certain types of procedures). The structures and tissues involved can be seen and touched, and they are directly exposed to the air. Examples of open surgery include herniated disk surgery, the removal of organs, such as the gallbladder (though cholecystectomy is now mostly done laproscopically) or kidney, and most types of cardiac surgery and neurosurgery.

Large wounds can cause ongoing pain and take time to heal, as well as restricting certain activities if surgeons have had to cut through muscle layers to reach the parts of interest. Over time, minimally invasive techniques have evolved that mean less damage to healthy tissue in the process of reaching the parts or organs of interest.

Minimally invasive procedure
A minimally invasive procedure (MIP) like newer surgical techniques, such as Minimally Invasive Surgery (MIS), require a simulated learning environment facilitated by intensive cadaveric training. MIP is any procedure (surgical or otherwise) that is less invasive than open surgery used for the same purpose. A minimally invasive procedure typically involves use of arthoscopic (for joints and the spine) or laparoscopic devices and remote-control manipulation of instruments with indirect observation of the surgical field through an endoscope or large scale display panel, and is carried out through the skin or through a body cavity or anatomical opening. Interventional radiology may offer techniques that avoid the need for surgery.

By use of a MIP, a patient may require only a band-aid on the incision, rather than multiple stitches or staples to close a large incision. This usually results in less infection, a quicker recovery time and shorter hospital stays, or allow outpatient treatment. However, the safety and effectiveness of each procedure must be demonstrated with randomized controlled trials. The term was coined by John EA Wickham in 1984, who wrote of it in British Medical Journal in 1987. A minimally invasive procedure is distinct from a non-invasive procedure, such as external imaging instead of exploratory surgery. When there is minimal damage of biological tissues at the point of entrance of instrument(s), the procedure is called minimally invasive.

Minimal incision technique
The minimal incision technique is a specialized surgical technique practiced by some physicians to remove masses or growths with minimal scarring and less recovery time. Most surgeons usually cut along 3/4 to the full length of the mass to access it or remove it. With the minimal incision technique the incision is usually about 1/10 the size of the underlying mass and the surgeon carefully dissects the mass out through this very small incision. A smaller incision forms a much smaller scar and results in less recovery time for the patient. This technique is useful for cysts or lipomas. Patients with such lesions on cosmetically or functionally important areas such as the face can gain great benefit from such techniques.

Specific procedures
Many medical procedures are called minimally invasive, such as hypodermic injection, air-pressure injection, subdermal implants, Refractive surgery, endoscopy, percutaneous surgery, laparoscopic surgery, arthroscopic surgery, cryosurgery, microsurgery, keyhole surgery, endovascular surgery (such as angioplasty), coronary catheterization, permanent spinal and brain electrodes, stereotactic surgery, The Nuss Procedure, radioactivity-based medical imaging methods, such as gamma camera, Positron emission tomography and SPECT (single photon emission tomography). Related procedures are image-guided surgery, robotic surgery and interventional radiology.

Benefits
Minimally invasive surgery should have less operative trauma for the patient than an equivalent invasive procedure. It may be more or less expensive (for dental implants, a minimally invasive method reduces the cost of installed implants and shortens the implant-prosthetic rehabilitation time with 4–6 months ). Operative time is longer, but hospitalization time is shorter. It causes less pain and scarring, speeds recovery, and reduces the incidence of post-surgical complications, such as adhesions. Some studies have compared heart surgery. However, minimally invasive surgery is not necessarily minor surgery that only regional anesthesia is required. In fact, most of these procedures still require general anesthesia to be administered beforehand.

Risks
Minimally invasive procedures are not completely safe, and some have complications ranging from infection to death. Risks and complications (also present in open, more invasive surgery) include the following:
 * Anesthesia or medication reactions
 * Bleeding
 * Infection
 * Adhesions
 * Internal organ injury
 * Blood vessel injury
 * Vein or lung blood clotting
 * Breathing problems
 * Death

There may be an increased risk of hypothermia and peritoneal trauma due to increased exposure to cold, dry gases during insufflation. The use of Surgical Humidification therapy, which is the use of heated and humidified CO2 for insufflation, may reduce this risk.

Equipment
Special medical equipment may be used, such as fiber optic cables, miniature video cameras and special surgical instruments handled via tubes inserted into the body through small openings in its surface. The images of the interior of the body are transmitted to an external video monitor and the surgeon has the possibility of making a diagnosis, visually identifying internal features and acting surgically on them.

Minimally invasive procedure

 * Minimally invasive heart surgery. Medical Encyclopedia, MedlinePlus.
 * Minimally invasive aortic valve surgery. CTSNet article.
 * Minimally invasive surgery yields benefits. The American Academy of Orthopedic Surgeons. Febr. 2003.
 * Minimally invasive cancer treatments highlighted. Science Daily. Nov. 2005.
 * Minimal Parathyroid Surgery. The minimally invasive technique utilizing intraoperative nuclear mapping, slso called Minimally Invasive Radioguided Parathyroidectomy, or "MIRP". EndocrineWeb. June 20, 2005.