Principles of Microsurgery

Principles of Microsurgery

The specialized surgical technique of using a compound microscope when operating on small and intricate structures of the human body is called microsurgery.

The procedure is also defined as the sewing together of tendons, nerves, or blood vessels to correct a disease, injury, or congenital defect.


The earliest use of microsurgical technique can be traced back to the mid-1500s. It was when surgeons first recorded their attempts to suture together torn blood vessels secondary to wounds incurred during the war.

However, it was not until 1912 when a French surgeon named Dr. Alexis Carrel won the Nobel Peace Prize for his pioneering work on surgical techniques. The techniques he developed are transplantation and vascular anastomosis—two surgical techniques that are still used to this day.

In 1920, a magnification aid in the form of a microscope was used during a middle ear surgery carried out in Sweden.

In the 1950s, ophthalmologists began using the microscope to achieve more accurate surgical techniques. Back then, the utilization of the operating microscope was considered revolutionary in several surgical disciplines.

In 1968, the first ever successful thumb replantations were carried out in Japan and England.

The first successful microsurgery performed in the United States was done by Harry Buncke, M.D. at Davies Medical Center (now Davies Campus of California Pacific Medical Center).

In 1972, after several years of research, Dr. Buncke performed the first toe to hand transplant on a firefighter from San Francisco. Professors Pesi Chacha and Robert Pho also performed hand microsurgery in Singapore in 1972. In Shanghai, Prof Chen Zhongwei published a textbook documenting 1000 such surgeries in the late ’70s, and did the first hand replantation in 1963.


Microsurgical procedures are carried out on minute and intricate parts of the body (i.e. tubes, nerves, and small blood vessels) that are visualized best under a microscope. Several surgical specialties are now utilizing microsurgical techniques.

For instance:

  • Otolaryngologists (ear, nose, and throat doctors) – carry out microsurgery on the delicate structures of the vocal cords and the inner ear.
  • Ophthalmologists (eye doctors) – treats glaucoma and other eye conditions, removes cataracts, and perform corneal transplants using microsurgery.
  • Urologists and gynecologists – reverses vasectomies (male sterilization) and tubal ligations (female sterilization) using microsurgical techniques.
  • Plastic surgeons – microsurgical techniques are employed to reconstruct disfigured or damaged tissues, muscles, and skin. They are also used when transplanting tissues from other parts of the body.
  • Hand surgeons who perform reattachment of severed extremities and use vascularized flaps to cover exposed body parts with soft tissues.


Majority of microsurgical procedures use a set of basic techniques. These techniques must be mastered by the surgeon. The techniques include vein grafting, blood vessel repair, and nerve repair and grafting.

  • Blood Vessel Repair

Connecting two separate or cut blood vessels to form a continuous channel is called blood vessel anastomosis. The procedure is also known as vascular anastomosis.

Anastomoses may be end-to-side (connecting one cut end of a blood vessel to the wall of another vessel) or end-to-end (between two cut ends of a blood vessel).

  • Vein Grafting

An alternative procedure to end-to-end anastomosis, vein grafting is often only pursued when it’s not feasible to reattach the cut ends of the blood vessel without any tension.

  • Nerve Repair

Nerve anastomosis or neurorrhaphy is the process of connecting two cut ends of the nerve.

The peripheral nerves are comprised of nerve fibers called fascicles. The fascicles are enclosed in a layer known as the perineurium. The nerve’s outer layer that encases the fascicles is called the epineurium.

Nerve repairs can involve suturing of the perineurium only, the epineurium only, or through both layers.

  • Nerve Grafting

Neurorrhaphy cannot be carried out without creating any tension when there is a large gap between cut ends of a nerve as it might interfere with postsurgical function. A piece of nerve from another part of the body may be utilized to create a nerve graft stitched into place utilizing anastomosis techniques.


A few reconstructive procedures that are otherwise impossible using conventional surgery are feasible with microsurgery.

Some of the most frequently performed microsurgical procedures include:


This emergency surgery is carried out to reattach a body part that is amputated like the foot, arm, or finger. Replantation surgery will entail a series of energy- and time-intensive steps in order to reattach all the structures while the part amputated is still viable.


In some instances, amputated parts cannot be reattached and tissues can become deformed secondary to injury or a congenital defect. In similar scenarios, transplantation might become the recommended option.

The second toe or the great toe can be removed from the foot and transplanted to replace a missing finger. Likewise, a segment of the rib can be utilized to reconstruct bones in the jaw and face.

Free-tissue Transfers

Also referred to as free flaps, free-tissue transfers are sometimes used to reconstruct damaged tissues that cannot be closed using traditional methods or cannot be treated with skin grafts. This can include constricted tissues (due to burns) or tissues that have been removed as a result of cancer treatment. Tissues that can be transferred using microsurgical techniques include the muscle, skin, bone, intestine, and fat.


Following a microsurgical procedure, the patient is given intravenous fluids. Typically, this would progress to a liquid diet within the next 12 to 24 hours, and a regular diet can be implemented soon thereafter. The patient, as well as the operated site, are kept warm and adequately hydrated.

To help drain the excess fluids, the surgical site might be elevated. Medications are also given to help manage the pain. The tissue turgor (fullness), quality of capillary refill, temperature, and colour of the surgical site is also closely monitored.

Ideally, the skin should be warm, pink, and have at least one to two second capillary refill. Tissue that is cool, blue, or pale, with rapid or no refill might indicate a blood flow problem.