Negligence is a scary word in whatever context it is used, but it can be especially unnerving when associated with errors committed during surgery. Surgical errors can have devastating effects on patients, causing such problems as excessive bleeding, injuries to vital organs, paralysis and even death.
Some of the most common surgical errors include:

Unnecessary surgery

Though becoming less common now -- partly due to advances in technology and improved diagnostic accuracy, but also because of insurance companies requiring pre-authorization for most procedures -- unnecessary surgeries do still occur. This error is now most prevalent in emergent procedures, such as emergent appendectomy and cholecystectomy (gall bladder removal). Most surgeons will attest that maybe only one out of every five to 10 of these particular procedures circumvents a possible rupture of the organ.

Failure to operate in a timely manner

This, too, has seen a drop in the number of occurrences per year because of improved diagnostic technology. This error is most likely to occur when emergency rooms are extremely busy and patients in dire need of surgery are forced to wait hours to be seen by a physician. Even a few hours can make a huge difference in the outcome of a gravely ill patient.

Surgical injury to internal organs

Though this particular type of surgical error is often due to negligence, proving it is malpractice is a completely different matter. There are inherent risks with any surgery, but a doctor should diligently avoid inadvertent injury to a patient during a procedure and make efforts to assure an injury doesn't occur. An example of an unrecognized injury can be seen when the surgeon inadvertently injures the bladder of a patient during a hysterectomy procedure.

Wrong-side/wrong-site/wrong procedure/wrong-patient surgery

This is perhaps the most egregious example of surgical error and inevitably leads to litigation.  According to the National Practitioner Data Bank, 2,217 wrong-side surgeries and 3,723 wrong procedures were recorded from 1993 to 2006, but those numbers may be far lower than what actually occurred. Because of inadequate reporting of the actual number of cases, it is estimated that these errors may be occurring anywhere between 1,300 and 2,700 times every year.

Failure to screen for a life-threatening disease

When a patient appears to a surgeon with a constellation of symptoms, the surgeon has a duty to rule out a life-threatening disease before assuming the patient has a benign condition. For example, a patient with bloody stools and abdominal pain may have hemorrhoids or diverticular disease (benign conditions) but they could also have cancer.

Failure to protect the patient from complications

Another duty of a surgeon is to identify known and foreseeable risks and minimize the chance they may occur. One example of this type of surgical management error is failing to anticoagulate a patient who is at risk of blood clots.