THE HEALTH REVOLUTION: Surgery and Medicine in the Twenty-first Century - 2. Operating on a Small Scale
Figure 1. Surgeons remove a patient's gallbladder through a tiny incision, using a laser beam and other minimal-intervention techniques. The operation is viewed on a TV monitor.
Figure 2. Inside an endoscope. With fine, flexible tubes, the surgeon can see around bends. Light travels down one bundle of optical fibers, and the surgeon views through another bundle. Wires control the instruments from outside the body. Pipes carry air and water.
Figure 3. Two surgeons use an operating microscope and fine instruments to reconnect a patient's severed blood vessels.
Figure 4. This hand-held robot arm with a probe is used to accurately locate brain tumors. CAT scan data of a patient's brain is fed into the robot's computer to create a three-dimensional image of the brain and tumor on a TV monitor. When the tip of the probe is moved on the patient's brain, the exact position of the tumor can be found while visualizing it on the screen.
Figure 5. Robot-assisted surgery. More and more operations in the future will be carried out by robots under the guidance of surgeons.
Until quite recently most operations followed a similar pattern. The surgeon would make a generous incision through a patient's skin with a sharp instrument called a scalpel and then hold the cut open with separating tools called retractors. Next the surgeon would pinch off severed blood vessels with forceps, and, if necessary, saw through bone to reach the problem area. Some operations must still be carried out in this way. But now the emphasis in surgery has shifted to doing as little damage to the patient as possible. This type of surgery is known as MINIMUM-INTERVENTION surgery and, among other techniques, involves passing instruments into the body through very small incisions and using new devices such as surgical lasers to avoid making unnecessary cuts (see Figure 1).
A View Through the Keyhole
Operating through cuts that may be only an inch or so across has given rise to the name KEYHOLE SURGERY. An instrument called an ENDOSCOPE enables surgeons to see what they are doing through such narrow openings.
The first endoscope, said to have been invented by Phillipe Bozzini of Frankfurt, Germany, in 1806, was just a narrow, rigid tube down which a light could be shone. With it, a doctor would have been able, for instance, to get a rather murky view of the inside of a patient's throat or stomach.
But endoscopes have been improved a great deal since those early days. Now they are made from optical fibers – fine, flexible strands of special glass or plastic along which light can travel for long distances and even around bends. Light is shone down one bundle of optical fibers, and the surgeon sees through another bundle, which is equipped with a strong lens. Also running down the length of the endoscope are control wires that allow the surgeon to guide and maneuver the instrument from outside the patient's body. Light traveling along the fiber-optic bundles relays a picture to a viewing device held in front of the surgeon or onto a video screen, enabling the surgeon and others to watch what is happening.
Surgery in a Tight Spot
In addition to giving an amazingly clear view of the inside of the body, an endoscope can also carry instruments to perform certain types of operations (see Figure 2). Because of the limited space within the endoscope's tube, however, none of these instruments can be more than about 3 millimeters in diameter, and all must be long and flexible. Examples include tiny cutting devices and forceps to cut away, grip, and pull away unwanted tissue (some of which may be analyzed in the laboratory); minute electrodes through which an electric current can be passed to seal blood vessels; and small balloons that can be used to open stuck heart valves.
Laser beams can also be directed down optical fibers in an endoscope to control bleeding, make bloodless cuts through tissue (since the heat from the laser immediately seals the wound), and destroy tumors and other growths inside the body.
Smaller even than the openings made during keyhole surgery are those used in another new technique, called PERCUTANEOUS SURGERY. Percutaneous simply means "through the skin." It involves making a tiny hole through the patient's skin and muscle with a needle just 1 millimeter across. Using a series of wider tubes, the surgeon temporary stretches the hole until it is a few millimeters across. During this procedure, instead of muscles and other tissues of the body being cut, they are just gently forced apart. Since hardly any blood is lost by a patient, no blood transfusions are needed, and no wounds that require stitches are left behind. The patient recovers almost immediately and may be able to leave the hospital less than a day after the operation.
Unlike the flexible tools used with ordinary endoscopes, percutaneous instruments are rigid. They are often merely modified or scaled-down versions of standard surgical instruments. Many were originally designed for operating on the ear.
|Small-scale Surgery on the Spine|
Slipped disks in the back are now routinely treated by percutaneous surgery. A disk is a doughnut-shaped piece of cartilage (a tough, gristly substance) that fits between the bones in a person's spine and acts like the suspension system of a car. Fluid surrounding each disk also serves to absorb shock waves that travel up the spine when a person moves around. Disks do not actually "slip." The cartilage simply gets worn and, as a result, may protrude from the spine and push painfully against a nerve ending. In the past the treatment for this condition involved a major operation followed by a length stay in hospital. But now the treatment can be carried out under a local anesthetic. Probing with a needle 1 millimeter in diameter, the surgeon locates the damaged cartilage. Then the surgeon begins to slip a series of larger tubes over the needle to open a gap 3 millimeters to 7.5 millimeters across. Miniature retractors are pushed down the final tube to pull the nerve endings out of the way, and tiny burs are used to grind away any bone that may be trapping the nerve. Next a very small cutting tool is inserted into the cartilage to slice into it. Finally, a minute screw-shaped device is inserted into the spinal column to drain off fluid and relieve pressure. This causes the bones on either side of the disk to come together and fuse, leaving the patient a little shorter but no longer in pain.
Today, if a person's arm, leg, fingers, or toes are accidentally cut off, they can sometimes be reattached and made to work again, thanks to advances in surgery. Simply reattaching an arm or leg is relatively easy, but reconnected numerous tiny severed blood vessels and nerves to restore full use of the limb calls for incredibly delicate techniques. These techniques are known as MICROSURGERY because they must be carried out while the surgeon looks at the work area through a special surgical microscope that magnifies about 30 times (see Figure 3).
Al least eight stitches are needed to ensure a blood-tight connection between two sections of a severed blood vessel. The nylon thread used is narrower than a human hair and is attached to a fine needle 3 millimeters long, made of the metal titanium. Although titanium costs much more than steel, it is the only material that can be worked to a fine enough point.
The idea of a robot carrying out a delicate operation may sound terrifying, but the time is fast approaching when robots will take their place in the operating room alongside human surgeons. In fact, a robot has already successfully performed surgery on an animal. In 1990, a ten-year-old sheepdog called Snook had its hip replaced at the University of California. A single-armed robot, programmed with the exact shape and size of the bone, used a rotary cutter to carve a cavity in the dog's thigh bone and then fitted with an IMPLANT.
At first, robots that take part in operations on people will be used mainly for tasks that are simple but tedious for humans to perform. For instance, during keyhole surgery a miniature camera often has to be held for long periods by a junior doctor while the surgeon carries out the procedure. In the future robots will be used in such circumstances to handle the camera, freeing human assistants for more complex jobs.
Robots will also play an increasingly important role in operations that demand a high level of accuracy (see Figure 4). In a typical future setup, the surgeon may not operate directly on the patient. Instead, sensory devices will track the movements of the surgeon and send signals to a detector unit. This unit, in turn, will control a motor attached to a robot holding a scalpel or other surgical tool so that the robot copies the surgeon's movements exactly (see Figure 5). The equipment could also be arranged so that fairly large movements by the surgeon's hands are turned into smaller, more delicate actions by the robot.
Entering Inner Space
Even more amazing developments early in the next century could result in surgeons being outfitted more like astronauts and doctors. Work is going on to create a space-age helmet for surgeons that will display the interior of the patient's body. Wearing the helmet, the surgeon will have the impression of being inside the patient's heart or stomach or whatever else the operation site may be.
Special gloves equipped with electronic sensing gear will detect all movements of the surgeon's hands and transmit the movements to a miniature robot carrying tiny instruments inside the patient. With such equipment it would not even be necessary for the surgeon to be present in the operating room. He or she could perform an operation remotely over a telephone line. This would allow a surgeon to operate on patients in different hospitals – even in different countries – from just once central location.