Shoulder arthroscopic surgery has become more utilized than open shoulder surgery over the past 20 years, with many citing fewer complications as a reason for the shift in treatment. However, after a review of the available evidence, Dr. Moen and his colleagues found that complications of arthroscopic surgery are not less devastating or prevalent than those of open joint surgery, they are simply different.
Arthroscopic surgery is performed by inserting instruments into a joint through small portals. Surgeons use small video cameras and tiny instruments to minimize joint disruption while they are repairing the joint. Prior to this technology, surgery was always open, with the skin, being cut back, muscles pulled aside, and the joint exposed for repair.
Surgical complications exist in three stages: prior to the surgery, during the surgery, and after the surgery. Prior to the surgery several things must be considered. The underlying patient pathology should be first taken into account. Certain procedures are best repaired with an open technique and others with an arthroscopic technique and if the wrong technique is used it can further subject the patient to problems down the road. Surgeon’s skill level and history with performing the indicated repair with an open or arthroscopic technique is another careful consideration. But, the highest probability for complication with arthroscopic surgery is choice of patient position during the surgery.
There are two main positions used for shoulder surgery. Bench position resembles sitting up in a recliner. Lateral decubitis position is the patient laying on their side with their injured shoulder facing up with the arm held away from the body by a special sling. Precautions for both of these positions include the standard ones for any surgery. The longer a body is held in a certain position, the greater the chance for skin breakdown and joint injury so the patient is carefully positioned and padded. If an extremity is wrongly positioned or held down too tightly nerves and blood supply can be negatively affected. Specifically, the head and neck must be carefully positioned and held in a neutral alignment to avoid risk of stroke or brachial plexus. This is especially true for the bench position as the patient is vertical and the neck could easily fall to the side. In the lateral decubitis position there is an increased risk for lower leg nerve injury because of the pressure on the side of the leg, and brachial plexus injury because the patient’s shoulder is under a certain amount of traction. Studies reviewed found the best arm placement for visualization to be 25-30 degrees of abduction (away from the patient’s side) and 30 degrees of forward flexion (in front of the body), with a decreased risk of brachial plexus injury with the arm positioned at either zero or 90 degrees of abduction and 45 degrees forward flexion with the least amount of traction required to complete the procedure. Authors strongly suggest that the surgeon be involved in the positioning of the patient to avoid foreseeable complications.
During the operation many nerves are vulnerable to injury. The portal site placement, or the holes through which the instruments pass, is crucial in that the nerves are avoided. The three main nerves at risk to direct injury are the axillary, musculocutaneous, and subscapular nerves. Certain surgical procedures present a greater risk to certain nerves, however each procedure follows specific precautions to decrease chance of injury. Another intraoperational complication, though rare, is a neurological event. These very serious events can include damage to nerves in the neck or eye nerves as well as venous air embolisms (an air bubble is introduced into the venous system and often results in death).
The most looked at serious complications of arthroscopic surgery are ischemic events where blood fails to flow where it should resulting in stroke, central nervous system cell death, and vision loss. Typically these events occur when the patient is placed in the seated “bench” position during surgery. When a person is awake, the nervous system regulates blood pressure, assuring blood is flowing to where it should. General anesthesia depresses this blood pressure regulation and the system can fail. Surgeons and anesthesiologists can mitigate the ischemic events by carefully monitoring blood pressure, applying regional or intravenous anesthesia, or performing the surgery in the less risky side-lying position.
Postoperative complications include joint infections and thromboembolic events (when a blood clot forms, breaks away, and moves to another area to block a blood vessels). Arthroscopy itself has a very low rate of infection, however the infection risk increases significantly with a transition to an open procedure during an arthroscopy. This infection risk is lowered by proper sanitization of surgical instruments, proper preparation of the patient’s skin and glove changing prior to conversion to an open surgery, and the patient taking antibiotics prior to the surgery. Thromboembolic events are rare for arthroscopic surgery and therefore have little evidence to investigate procedures for their prevention.
Even though arthroscopic surgery is rapidly becoming the method of choice for shoulder patients, there are surgical complications that must be considered. These complications can be minimized by careful patient selection, proper choice of surgical technique (open versus arthroscopic), the patient’s position during surgery, thorough knowledge of shoulder anatomy, and careful use of anesthesia.