Javier Aragon Sanchez, MD, PhD discusses basic principles of the identifying and treating of diabetic foot infections. Dr Sanchez also discusses when it is absolutely necessary for patients to undergo surgery for diabetic foot infections.
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TAPE STARTS – [00:00]
Speaker: Going along in a line of infection, any microbial therapies, I thought it will be nice to have Paul Brandvardy [phonetic] come back to us today and speak on his favorite topic diabetic foot osteomyelitis. The question is, is surgery best? So let's welcome Dr. Aragon-Sanchez.
Dr. Aragon-Sanchez: Thank you. I am going to talk my favorite field is diabetic foot osteomyelitis. Probably you know that approximately between 10% to 20% of diabetic foot infections seen in the ambulatory sitting may be complicated by osteomyelitis. However, this percentage increase in patients hospitalized for diabetic foot infection. In our experience with 292 patients, 63% of the patients have osteomyelitis with or without soft tissue infection. However, only 37% have exclusively soft tissue infections. When the patient comes into our department, you can see that 71% have been given with antibiotic treatment prior to admission in our department and this is the reality. A 61% of the patients admitted in our department with osteomyelitis have the bone exposed, gangrene, destruction of soft tissue envelope or soft tissue infection.
Only 39% of the patients have chronic osteomyelitis without this previous finding. And this is the real problem with antibiotics in cases of diabetic foot osteomyelitis. For the moment, there is no evidence. For the moment, one cannot predict with certainty for which of the patients medical therapy will fail and the failure could be associated with more proximal level of amputation. It has been reported by Henke [phonetic] that preadmission antibiotic use was associated with limb loss. We see many times incorrect use of antibiotics. For example you can see this patient given antibiotics for one year. You can see deterioration of the bone after one year with antibiotics. Another time, for example, in this case waiting for the resolution of the bone infection exclusively with antibiotics. You can see the osteomyelitis of the base of the fifth metatarsal bone involved in cuboid of the base of the fourth metatarsal bone. Waiting for resolution with antibiotics, you can see there was dorsal, plantar and medial spreading of the infection and in these cases, we had to perform a very extensive debridement of the lateral of the plantar compartment. You can see in this case bubbles of free gas in soft tissue in the central compartment of the foot. In my opinion, there is no doubt that when the patients have the bone exposed, there is extensive bone destruction on x-ray, progressive bone damage on sequential x-ray, gangrene.
The soft tissue envelope is destroyed or there is associated spreading of soft tissue infection, surgery is totally mandatory. Surgery should be carried out as soon as possible for preventing a more proximal level of amputation. However, in cases of chronic osteomyelitis without the above finding, we can go for antibiotic or surgery depending on several factors. When you choose antibiotic treatment for treating osteomyelitis, there is some advantage, avoids surgical procedure, potentially avoid hospitalization, preserve more of foot, may shorten the duration of the hospitalization. However, disadvantages, increased recurrences, risk of reulceration if uncorrected foot deformity, antibiotic-related toxicity, risk of developing antibiotic resistance and risk of Clostridium difficile disease. Further, there is some resolved issue concerning medical treatment for diabetic foot osteomyelitis. For example, what is the [indecipherable] [05:13] offloading made of for diabetic osteomyelitis because you can see the severe bone damage when treating calcaneal osteomyelitis without adequate offloading. How wound care is needed? How can infection be spreading through the foot be detected? When should medical treatment be abandoned and surgery is approached? Are outcome worse with delay in surgery? And when can a patient who undergoes treatment for osteomyelitis be considered cured? There is agreement that definitive diagnosis of diabetic foot osteomyelitis is based on microbiology, isolation of bacteria from sterile bone and histopathological changes.
In this case, you can see infiltration of polymorphonuclear cells in bone tissue. This is an acute osteomyelitis. And this is what we call the gold standard for diagnosis and treating osteomyelitis because there is agreement that the base method of choice, antimicrobial agent for treating osteomyelitis should be based on the results of bone culture. And this is the gold standard. The percutaneous bone biopsy. But despite of the fact that percutaneous bone biopsy is considered the gold standard, this technique isn't available in many centers and sometimes in other patients, it's easier to get a bone sample. For example, you can see this patient, probe to bone was positive, [indecipherable] [07:06] you can take a bone biopsy through there also. We send the bone piece to microbiology and pathological department. You can see in this table, the outcome of several series dealing with medical treatment of diabetic foot osteomyelitis. In blue color, you can see the series in which bone biopsy was not carried out and in green color, series with bone biopsy. And you can see the series were totally different. The remission criteria were totally different.
For example, in this area with 82.3% of remission rate, the remission criteria was patients with viable with limb intact. They talk about apparent remission. The remission criteria were totally different between the series. The bone biopsy was taken in this three series from Senaver [phonetic], 52% of the patients underwent a percutaneous bone biopsy, 64% of remission rate. And two series from Spain and Lisane [phonetic] from France to achieve with bone biopsy through the ulcer 73% and 82% of remission rate. We can expect more or less 75% to 80% of remission rate treating patient with antibiotics. Regarding surgery, treating patients with diabetic foot osteomyelitis with surgery has shown advantage, remove the necrotic bone, remove bacterial biofilm, remove the bony prominences and it gives an opportunity to stabilize the foot. Disadvantage - may increase the risk of reulceration, is expensive and risk of operative morbidity, may destabilize the foot, risk of transfer ulcer. Again, there is some resolved issue. Concern is surgery for diabetic foot osteomyelitis. Who really needs surgery? Some group treats patient with antibiotic for one month in order to reduce soft tissue infection, then elective bone surgery. Postoperative culture guide antibiotic base, bone samples, what type of surgery, who can safely perform the surgery and recurrence or reulceration are more frequent with surgery and finally the same question that patient treated with antibiotics.
When can a patient who undergoes treatment for osteomyelitis be considered cured? Surgical approach to the patient with diabetic foot osteomyelitis has changed considerably over the years. In 1997, we only performed amputation in this patient because it was the dominant thought in my country, remained the dominant thought. And five years later, we start to develop new surgical techniques in order to save the patient's limb. Now, currently our surgical approach is based on several steps. We perform early conservative surgery with total or partial removal of infected bone and soft tissue. We try to have prophylactic purpose as well. Intraoperative bone biopsy for microbiology and pathology. Postoperative systemic antibiotic treatment based on bone culture. We left open wound to heal by secondary intention. It permits drain the residual infection especially when defective bone has not been totally removed. Good wound care, offloading and we assume that the infection is resolved when the wound is epithelialized for [indecipherable] [11:38]. This is a typical case with ulcer of the medial side of his foot over the hallux valgus deformity. As you can see, there was destruction of the bone. This situation will remove the infected deformity because removing the first metatarsal bone leads to severe biomechanical disturbances.
We prefer to save the first metatarsal bone. As you can see the healing time was 110 days, six and half years without recurrence. This is a typical case with involvement with a severe destruction of the interphalangeal joint. You are going to see the approach of a general surgeon, I apologize. We had to remove all the infected soft tissue, remove the tendons. The finger is the best instrument removing the bony prominence. Finally, packing with alginate. Okay.
You can see the healing course and finally the healing time 34 days and 10 years without recurrence. This is our concept of conservative surgery procedure in which only infected bone and non-viable soft tissue are removed without amputation of any part of the foot. The outcome of the surgical treatment of diabetic foot osteomyelitis depends on the location of the bone infection. In our experience, 90% of the patients have osteomyelitis located in the forefoot, 5% in the mid foot and 5% in the hind foot. Limb salvage was achieved in 94% of the cases of forefoot osteomyelitis and only in 72.3% of the cases of mid and hind foot osteomyelitis. And the outcome also depends on the clinical presentation of diabetic foot osteomyelitis. We proposed a classification into four classes depending on the clinical presentation of the patient. Class 1 is osteomyelitis with no ischemia or soft tissue involved, class 2 with ischemia but without soft tissue involved, class 3 is osteomyelitis with soft tissue involved but no ischemia, class 4 osteomyelitis with ischemia and soft tissue involvement. And you can see in the Chi square for trend, there was a significant association between the classes, the severity of the infection, the change of undergoing any amputation, the high level of amputation and the mortality. As you can see in the class 1, osteomyelitis with no ischemia or soft tissue involved, the limb salvage rate was cent percent of the cases. However, sometimes we have to re-operate the patient and I talk about this morning, 20 patients in this area of diabetic foot osteomyelitis, 24.7% require re-operation because of persisting infection.
The variable associated with the need for re-operation where pressing on necrosis having had conservative surgery, limb ischemia and previous ulceration. And any surgery including conservative surgery has biomechanical consequence in the foot. You can see that conservative surgery was very safe to remove the infection. Only 4.6% of recurrence of the infection with this technique; however, reulceration at the new site 36.9% after 100 weeks of followup. In the cost regression analysis, the reulceration was associated with the plantar location of the ulcer during the first episode on Charcot deformity. We designed a randomized controlled trial to try to give a response to the eternal dilemma between surgery and antibiotics in cases of diabetic foot osteomyelitis. We designed this randomized comparative trial, but I would like to highlight this figure. Only 53% of the patients, we were able to randomized because we have very severe exclusion criteria. Severe infections were excluded, necrotizing soft tissue infection, patients with peripheral arterial disease, Charcot foot and when the bone was exposed at the borderline of the ulcer. Excluding this patient's foot condition because there was a general exclusion criteria.
As you can see finally, the antibiotic group, the conservative surgical group, the total healing was 75% in the antibiotic group versus 86.3% without significant difference between antibiotics and surgery. The median time to healing was seven weeks in the antibiotic group and six within the surgical group again without significant difference. For the reason in cases of forefoot osteomyelitis without ischemia, without soft tissue infection, antibiotics may be similar to conservative surgery in cases of diabetic foot osteomyelitis. We also tried to demonstrate surgery may be able to reduce the duration of antibiotic therapy. You can see, this our medical series, it's the last study from Tong [phonetic]. We say six weeks of antibiotic therapy and the surgical series, I have a long duration of antibiotic therapy, 36 days, Cowaky [phonetic] 19 days and in our randomized controlled trial, the patient who underwent surgery only have 10 days of postoperative antibiotic therapy. In this way, we think that antibiotics of course may reduce the duration of antibiotic therapy. In our previous experience, antibiotic therapy, the duration was variable depending on the clinical characteristic of the patient.
The patient with peripheral arterial disease, those requiring re-operation, those requiring open transmetatarsal amputation had longer duration of antibiotic therapy. And sometimes we are able to do a do quasi-surgical treatment because this is a very common situation. The patient presenting in outpatient facility with the bone exposed and neuropathic ulcer, it is very easy to remove some piece of bone without any type of anesthesia because the patient is totally neuropathic, no pain. And in this situation, we are able to resolve the problem of the patient. You can see the healing in 27 days. It's very easy. I think it's not worthwhile to take percutaneous bone biopsy for this type of patient because it's very easy to remove the bone in outpatient facility without admission. Therefore, we come back to the beginning. Diabetic foot osteomyelitis, is surgery best? Depends, depends on the clinical presentation and [indecipherable] [21:36]. In cases of severe infectious gangrene and spreading soft tissue infection, there is no doubt, surgery. In cases of foot infection associated with substantial bone necrosis or progressive bone destruction despite antibiotic, surgery of course. Non-skilled surgeon dealing with diabetic foot osteomyelitis and conservative surgeries, we try antibiotics.
Not complicated diabetic foot osteomyelitis and bone biopsy [indecipherable] [22:05] label antibiotics. Infected pathogen resistant to our labeled antibiotics, deciding for surgery. There are also bone biopsy easily taken as outpatient, antibiotics. Full postoperative biomechanical foot is likely for example mid and hind foot infection, antibiotics. Biomechanical disturbances and bone deformity surgically correctable, we decide for surgery. If the patient is too medically unstable for surgery, of course, antibiotics. And in cases of osteomyelitis and critical limb ischemia, while waiting for revascularization, we start with antibiotics and after revascularization we can decide whether it's better to continue with antibiotic or performing conservative surgery approach. Finally, in conclusion the objective of the treatment is to remove the infection from the bone. Classically, this has been carried out for several type of amputation, but I really think that today with the early conservative surgery and postoperative antibiotic or exclusively antibiotics guide by bone culture, we are able to give our patient the opportunity to save the limb. Thank you very much.
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