Surgical Site Infection Risk in Patients with Diabetes
Written by Dr. Benjamin Weaver
With 7.8% of the United States population (~23.6 million people) estimated to be diabetic, one can see how diabetes has become an increasing challenge for the medical community. It has been estimated that nearly a third of these patients are unaware of being diabetic. This prevalence will rise, as nearly 25% of adults over 60 are diabetic and there are increasing numbers being diagnosed in younger patients. Approximately 366 million people will have diabetes worldwide by the year 2030, most of these in developing countries. Foot disorders such as ulcers, infection, Charcot neuroarthropathy and peripheral arterial disease (PAD) are the most common causes of hospital admissions in diabetics. As diabetes mellitus is considered a lifelong condition, one can see the true impact on the healthcare system overall.
Peripheral neuropathy is one of the most common complications found in diabetics, prevalent in anywhere from 14-60% of the diabetic population. Peripheral neuropathy leads to sensory, motor and autonomic dysfunction, and this loss of protective sensation often causes these patients to fail to seek timely medical care for their conditions.
Surgical procedures are often unavoidable in patients with diabetes, and can even help reduce future risk of ulceration. But high postoperative infection rates in this patient population pose additional challenges to practitioners.
Foot surgery in patients with DM can be elective or preventative. Due to concerns with increased infection rates and slow healing of skin and bony structures in diabetics, elective surgery is performed with extreme caution. Prophylactic or preventative surgery is performed in those diabetics with pre-ulcerative areas, bony prominences and stable, non-infected ulcers. The purpose is to prevent ulcerations due to these bony prominences or to assist in healing of current ulcerations. Multiple types of surgeries can be performed based on the underlying bony deformity found, including hammertoe repair, bunion repair, metatarsal osteotomies, bone resections, Achilles tendon lengthenings for ulcers in the forefoot area and many more. Fracture repair is often required in diabetic patients. Those patients with Charcot foot deformity not treatable with bracing may require surgical intervention also.
It has been noted that diabetic patients without neuropathy can be treated with standard surgical technique and post-op care, but those who are neuropathic should have more fixation, be seen more often and remain non-weightbearing for approximately double the time period.
Peripheral arterial disease can also complicate the surgical site in diabetics, especially those with an insensate foot. Lack of blood flow to the surgical site not only affects the patients ability to heal the site quickly, but can also lead to an inability to fight off potential infection at the surgical site in the diabetic patient. Surgical site infections are infections that occur with 30 days of a surgical procedure, or within 1 year if an implant was inserted and is related to the surgery. One study found that by controlling factors such as hypothermia, blood glucose levels, removing hair from the surgical site and administering procedure-specific pre-operative antibiotics for an appropriate time frame, infection risk can be decreased.
One study showed a post-op infection rate of 6.7% in diabetic patients with neuropathy but no open wound undergoing forefoot surgery. A recent study was performed to examine wound infection rates involving 57,183 patients with ankle fractures undergoing repair. This study showed that non-diabetic patients had an infection rate of 1.4% after surgery. Diabetics without neuropathy or other comorbidities had a rate of 3.55% and diabetics with neuropathy or other comorbidities had an infection rate of 7.71%. Other reviews have found similar percentages, indicating that there is an obvious increased risk of infection in diabetics undergoing foot and ankle surgery. This implies that foot and ankle surgeons must have appropriate protocols in place to lessen these infection rates in their patients. First and foremost, comorbidities such as peripheral neuropathy and peripheral arterial disease must be diagnosed and managed prior to preventative surgery.