Surgical Insights On Neuropathic Ulcers

Author(s): 
Clinical Editor: Lawrence Karlock, DPM

Q: What is the role of pre-op noninvasive vascular tests in your practice? Which ones do you use and why?
A:
Drs. Catanzariti and Steinberg routinely perform preoperative non-invasive vascular testing for diabetes patients who are undergoing elective foot surgery. Dr. Catanzariti says he typically orders pulse volume recordings, toe pressures and transcutaneous oximetry. In addition, Dr. Steinberg says he’ll get Doppler waveforms, segmental pressures, TBI and ABI. He emphasizes paying more attention to the TBI over the ABI given the medial arterial calcification that commonly occurs at the ankle, which can cause false elevation of the ABI measurement.
When Dr. Karlock is treating a patient with diabetes who has palpable dorsalis pedis and posterior tibial pulses, he feels that he doesn’t have to do any vascular testing in this situation. However, if he is unsure of vascular flow to the foot, he will order testing with an accredited vascular lab at the local hospital.
In these scenarios, Dr. Karlock says he is primarily looking for an absolute toe pressure number. He relies upon toe pressures above 55mmHg, noting that patients with this number have had uneventful healing in up to 97 percent of diabetic foot surgery cases.
If Dr. Karlock is still unsure after vascular testing, he will refer the patient to an accredited, board-certified vascular surgeon for preoperative vascular clearance.

Q: Are there any different postoperative protocols you follow with these patients?
A:
Emphasizing that he is “extra cautious” in the postoperative period, Dr. Karlock says he limits weightbearing in these patients as much as possible and gives them oral antibiotics. Dr. Karlock notes that the rate of soft tissue infection when operating in the face of an open ulceration ranges between 15 and 20 percent, according to most of the literature on the subject. He says he usually places these patients on an antibiotic that covers gram-positive organisms. Dr. Steinberg says he generally emphasizes cephalexin 500mg qid for seven to 10 days and observes the wounds more closely.

While Dr. Catanzariti feels the postoperative course for diabetic patients is essentially the same as for non-diabetic patients, he says there are several things he does differently. When these patients need a cast, Dr. Catanzariti notes he will typically use a total contact cast or a cast that specifically offloads any areas of osseous prominence.
Given that a patient’s lack of protective sensation may predispose him or her to iatrogenic ulceration with any cast, Dr. Catanzariti emphasizes that he’ll often have diabetic patients return to his office more frequently and at shorter intervals. He says the more frequent office visits allows him to ensure there are no iatrogenic ulcers or impending infection from the cast. Even when he doesn’t apply a cast, Dr. Catanzariti recommends more frequent dressing changes given the higher risk of infection.
Dr. Steinberg adds that employing unna boots or other compression systems can be helpful in controlling the common postoperative edema in these patients and preventing dehiscence of the incision site.
Dr. Catanzariti also considers taking serial radiographs more frequently for diabetic patients after elective foot surgery to evaluate for any impending Charcot process. He notes a relatively high incidence of acute Charcot changes following elective foot surgery or trauma in the diabetic foot. Accordingly, Dr. Catanzariti has a higher index of suspicion with these patients and makes a point of educating them about possible Charcot changes.

Q: How often do you address an equinus deformity in diabetics with plantar ulcerations? What procedure do you prefer?
A:
When Dr. Catanzariti sees equinus deformity in these situations and believes it is a contributing factor, he says he’ll consider performing an Achilles tendon lengthening as an ancillary procedure to the primary elective procedure whether it’s in the forefoot or hindfoot. Dr. Catanzariti says his typical approach is a three-incisional hemisection Achilles tendon lengthening.

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