The compiler of these short notes came across this book, the cover of which is reproduced below, which is the personal experience of a single plastic surgeon (Dr. Vinay Saoji, MS, Plastic Surgery), from the city of Nagpur, in the state of Maharashtra in India. This is a virtual treasure trove of information on the standard aspects and surgical practice for diabetic feet. The photographs are of a high quality and therefore Dr. Saoji was requested to prepare a shortened version of the book which is printed below. It is the kind of chapter which will be useful for undergraduates as well as post-graduates in general and plastic surgery as well as laypeople. The chapter is not didactic but presents valuable insights that the author acquired over a quarter century of practice and will go a long way in providing a methodology for treating this condition.
Diabetic Foot Infections (DFI):
Introduction of subject:
Infections in diabetic feet are difficult to treat and take a long time to heal; if at all they heal. Patients often need prolonged hospitalization and a dedicated team. Many times the treatment is expensive too. The infection can rapidly worsen and become a medical emergency, needing surgical treatment. Infection of soft tissue and bones of the foot is one of the commonest causes of amputation, keeping trauma aside.
The infections that occur in a neuropathic foot or an ischemic foot are included here. Diabetic foot infections occur most often in a neuropathic foot (or ulcer) and less commonly ischemic foot (or ulcer). Infections could be mild, moderate or severe and it may be associated with Comorbidity.
Infected sensory neuropathic foot:
When protective sensations are lost the trauma may go unnoticed. Trivial trauma such as frictions, abrasions, thorn pricks, iron nail injury, foreign, bodies, blunt trauma (stubbing) stay neglected and eventually get infected.
Infected autonomous neuropathic foot:
In autonomous neuropathy the skin becomes dry, scaly, itchy and fissured. These fissures act as an entry point for infection.
Infected motor neuropathic foot:
Infection in ischemic diabetic foot:
Treatment of infection in ischemic diabetic foot is always challenging and in spite of optimum management the outcome is often not satisfactory.
Infection in neuro ischemic foot:
This is probably one of the worst combinations. The trilogy is distinctly seen here: neuropathy, ischemia and infection.
Why are foot wounds and infections unique?
Compared to any other part of the body the foot has more white tissue; such as plenty of plantar fat, 109 ligaments, dozens of tendons, and 37 joint capsules. There is very little muscle mass. This unfavorable proportion makes healing more difficult in foot and more so in diabetes.
Because of sensory neuropathy the wounds are not painful and the patient keeps on putting weight on these wounds. The weight on the wound contributes to worsening the wound. Also weight on the wound breaks the healing (bridges of collagen and neo vessels) repeatedly, making the wound a chronic entity.
So also due to ischemia, healing becomes a difficult process.
If all other parameters are the same, then infection severity is less in non-diabetics. Raised sugar levels are also to blame for flare in infection.
The foot infections may be divided as: superficial and deep.
Superficial infections: here infection is restricted to skin, subcutaneous tissue and plantar fat which lies between plantar fascia and plantar skin.
Deep infections: when infection involves tendons, ligaments, plantar fascia, joints and bones.
Foot has few potential spaces such as heel space, web space, plantar space(s) and dorsal space. Significant infected material can stay in these spaces before getting noticed. Infection of these spaces is considered as deep infections
Severity of infection: Mild, moderate and severe;
Mild Infections: they may be as trivial as infected granuloma of ingrowing toenail, paronychia, lymphangitis, superficial abscess or small area of skin necrosis without systemic involvement.
Moderate infections:
This group lies midway between severe and mild variety. Small area devitalization, smaller tissue loss or gangrene of a single toe are few examples. This may be associated with some systemic involvement; however 50% patients with moderately severe infection do not have systemic signs such as malaise, fever, chills etc.
Severe infection:
Deeper and more severe infections are: ascending infection with extensive proliferation, tendonitis, deep large abscesses, deep and large central plantar space infections, myositis, septic arthritis, osteomyelitis, vasculitis, large area of necrosis and major gangrene. This is often associated with systemic involvement.
Systemic signs and symptoms of severe infections:
1) Nausea, vomiting,
2) Malaise (feeling of sickness), anorexia.
3) Hypotension,
4) Confusion, delirium, irrelevant talk and abnormal behavior
5) Temp > 38 or < 36.
6) Tachycardia > 90/Minute
7) Taccypnoea, respiration > 20,
8) Leukocytosis > 12000 or leukopenia < 4000
Severe infection: The plantar wounds are often in a bad state and advanced stage when first seen by the surgeon, because these wounds are not seen and attended to in initial stages. This patient (see fig 1 below) had lost his second toe in a similar episode a few years ago.
Infection in diabetic patient can worsen to limb threatening or life threatening situation if there are comorbidities, such as chronic renal failure, cirrhosis of liver or malignancy to name few.
Dermatological infections in diabetic foot: mostly mild infections
Eczema (etching + redness), Tinea pedis (also known as ringworm) Athletes foot (superficial fungus infection), scaly too dry skin, cracked skin (fissures) are few dermatological conditions that frequently affect diabetic foot. Because of associated neuropathy and ischemia, they acquire special significance.
Diagnosis of infected diabetic foot:
Out of four classic signs and symptoms of infection: calor (raised temperature), rubor (redness or erythema), dolor (pain) and tumor (swelling) at least 2 classic signs of infection should be present before diagnosing infection. However in diabetic foot the cardinal signs are altered, hence the picture is confusing.
- In immuno-compromised patient’s host response is subdued, hence a large number of patients (40-50%) do not show high grade fever and leukocytosis.
- Pain tenderness may be absent in neuropathic patients.
- Erythema is less pronounced in Ischemic patients.
- Assessment of associated neuropathy, ischemia must be done.
Fever, chills, malaise, nausea, vomiting, hypotension, tachycardia, confusion, acidosis, leukocytosis and acute hyperglycemia are signs and symptoms of metabolic instability and systemic toxicity. 50% with moderately severe infection will not have systemic signs of fever, chills etc. This neuropathic patient had almost no systemic signs of systemic involvement despite such obvious infection.
Diagnosis in below shown obvious cases is not difficult, where all the signs of infection are so obvious.
Infections following trivial trauma:
Moderate to severe foot infections often begin in an inconspicuous looking, trivial trauma, which so many times are forgotten or missed all together. They occur at the workplace or at home. Because they are too minor, they are treated rather casually.
So many times the patient is not aware that he or she is a diabetic until the wound becomes a major issue and the person is investigated for diabetes. If they turn out to be accidently detected diabetic, then disease is often in a significantly advanced stage. Had it not been so advanced diabetes, the infection might not have been so severe. In brief let us put it this way “severer is the infection following trivial trauma, severer is disease and often very high is the first blood sugar”. Well, the diagnosis of diabetes comes as a shock for most of the patients.
There are many causes for trivial trauma to occur. Many of them are related to footwear. The reasons could be diagonally opposite, i.e. wearing faulty footwear or no footwear at all, as seen in barefoot work/ walk.
Causes of trivial trauma: bare foot work or walk:
Cause of trivial trauma: again footwear: this time wearing it: shoe bite!
Minor thermal injuries and look at causes! There are so many!! Hot silencer burns
Walking on hot floor and Tar road :
Other causes of minor injuries and infection:
Bite injuries and infection:
Surprisingly neither rat bites nor ant bites are rare. All rat bite injuries are likely to get infected in diabetics.
Investigations in infected diabetic foot
Patients must be investigated systemically and locally for infective pathologies. Investigations of Neuropathy and ischemia are written earlier.
- Blood Investigations:
- Fasting and postprandial blood sugar
- HBA1c
- Complete Blood Count (CBC)
- ESR
- HIV and HB1AC and weight measurement
Additional investigations: ECG, X-rays chest, X-rays foot AP and lateral views, LFT, KFT, lipid profile, ophthalmic fundoscopy, urine routine, urine blood sugar and culture- sensitivity of pus swab
Blood tests
Often show Leukocytosis, raised ESR, and raised CRP level (C – reactive protein). CRP level > 200 suggests severe infection.
X-RAYS:
Red, swollen, deformed toe? Think about the possibility of osteomyelitis. ESR > 70 mm with an ulcer? Think osteomyelitis. Very foul smelling? Think osteomyelitis. The diagnosis is usually not difficult. Plain x-ray is often sufficient in such situation.
Early x rays may be deceptive:
Investigations: Probe to bone test
Visible or palpable bone suggests strong possibility of osteomyelitis. A blunt probe is passed inside the wound; if bone is felt then most likely the patient has osteomyelitis.
Bone Biopsy:
Infection in bone is best confirmed by bone biopsy (curettage) but still it is not done regularly. FNAC is not so accurate, so it is not recommended.
Microbiology: Culture and Sensitivity Test (CST).
Microbiological examination is helpful in knowing which organisms have infected the wound and which antibiotics should be prescribed. Usually tissue samples, mostly pus, are collected from the deeper part of the wound and sent to a pathology laboratory in a culture media.
Sample should be collected before “painting” (scrubbing) the wound and commencement of empirical antibiotics.
Which micro-organisms are likely to be found in CST?
- Mild infections: mostly show mono microbial
- Severe infection poly microbial
- The common organisms are staphylococcus aureus, beta haemolytic streptococci, followed by E coli, proteus, Klebsiella.
- Uncommon organisms are – bacteroides, clostridium and Methicillin Resistant Staphylococcus Aureus (MRSA).
- MRSA is a problem organism. Hospital acquired MRSA is far more problematic than community acquired MRSA.
- Acute wounds show staphylococcus aureus and /or streptococci.
- Chronic wounds show: staphylococcus , streptococcus , enterobacter and may show fungi
- Constantly wet and old wounds may show pseudomonas and sometimes fungi.
- Extremely foul odour? Rapidly worsening wound? Crepitus? : Most likely it is anaerobic infection.
A word of caution about mycosis:
Advanced investigations in diabetic foot infections: MRI, PET scan
MRI is diagnostic but it is not a first line investigation. It can detect soft tissue and bony infections at an early stage, however this facility is not available at all places and is expensive. It has less practical value
Radioisotope scans, Nuclear medicine scans (Technetium or WBC labeled scans) are expensive, time consuming, hence do not have practical value. PET scan / Bone scan (TC99). Though the accuracy rate is 94% to 100%, this is also expensive and does not have practical value.
Classification of infections in diabetic foot:
Following two classifications are followed widely, world over.
- Infectious Disease Society of America: IDSA.
- International Working Group on Diabetic Foot : IWGDF
Basis of these two classifications is almost the same. It is based on severity of infection, systemic involvement and complications. A brief outline is given below. The category of IWGDF is written in bold letters. As a plastic surgeon and a team member of “step by step” “diabetic foot education program member” I use IWGDF grading while documenting or communicating.
IDSA No infection = IWGDF grade 1
IDSA Mild Infection: IWGDF grade 2 Erythema, induration, tenderness, warmth are >2cms. Infection limited up to subcutaneous tissue.
IDSA Moderate infection: IWGDF grade 3 as above and at least one of the following i.e. lymphangitis, deep abscess, gangrene, muscle and/ or bone involvement is present. The infection is deeper to superficial fascia, but there is no systemic involvement and the patient is metabolically stable.
IDSA Severe infection= IWGDF grade 4: Infection as above and fever, chills, tachycardia acidosis or azotemia (uremia)
Management of diabetic foot infections
While mild and moderate infection may not need hospital admission. It is mandatory to admit all critically ill patients:
Guidelines for antibiotics therapy
The antibiotics coverage is essentially subdivided in
- Empiric 2) Definitive type.
Empirical antibiotics may be based on severity of infection, allergies if any, previous history of antibiotics, its response that time and outcome of previous regime.
Frequently empirical antibiotics are aimed to cover (gram +ve) staphylococci and streptococci.
But when infection is severe; foul smelling, gas producing, and then gram –ve coverage is also added.
Empirical prescription of antibiotics needs modification mostly according to clinical response or according to availability of culture and sensitivity reports.
Diabetic foot being a chronic problem, we see the patient repeatedly and we often know which antibiotics are accepted well and when the patient has done well or not done well.
Usually the picture repeats in a similar way and we tend to prescribe the same empirical regime again (and again). I remember one of my patients was so scared to take amoxicillin because of loose motions and vomiting that he requested me ”please don’t give me that again”.
IV / parenteral antibiotics are indicated in severe infection and when a patient is unable to take oral medications or antibiotics are not available in oral forms, such as Netlimycine, Tigecycline etc.
The cost is also an important factor in the Indian scenario. On many occasions financial restrictions force us to opt for less than optimum. The antibiotics should be discontinued when signs and symptoms of infection disappear, even if the wound has not healed completely.
IWGDF and IDSA suggest there is no one particular superior regime, duration and mode of administration and proper individualized proscription is most important.
Empirical antibiotics in mild infections:
| Parental route of antibiotics | ||
| ampicillin sulbactam | 2-3 gm IV | TDS |
| Clindamycin | 600-900 mg IV | TDS |
| Ertapenem | 1gm IV | OD |
| Imipenem cilastatin | 500 IV | TDS |
| Ceftriaxone | 1-2 gm IV | OD |
| Clindamycin | 600-900 IV | TDS |
| Metronidazole | 500 IV | TDS |
| Oral route of antibiotics | |||
| Cephalexin | 500 | Orally | QID |
| Amoxy-clauvante | 625 | Orally | BDS/TDS |
| Levofloxacin | 200 | Orally | BD |
| Moxifloxacin | 400 | Orally | OD |
| Clindamycin | 300-400 mg | Orally | TDS |
| Doxycycline | 100 | Orally | BD |
Empirical antibiotics in moderate infections:
In moderate infections parenteral antibiotics are needed for the first few days and later on can be switched to oral medications. The total duration is 2 to 4 weeks.
| Usually Cefazolin | 1-2 gm IV | QID |
| Ceftriaxone | 1 -2gm IV | OD |
| Vancomycin (Drug of choice in MRSA) | 30 mg / kg IV | BD |
Empirical antibiotics in severe infections: Following antibiotics are commonly used.
| Piperacillin + Tazobactam | 4gm + 0.5gm IV | TDS |
| Ciprofloxacin + Clindamycin | 400mg IV 600 to 900 IV | TDS |
| Imipenem + cilastatin | 500 IV | TDS |
| Vancomycin + Ciprofloxacin + Metronidazole | 30mg /kg IV 400 IV 500 IV or oral | BD |
For MRSA, MSSA, Pseudomonas, osteomyelitis and associated renal impairment regime may need to be little modified.
For MRSA, severe infection Vancomycin is the drug of choice, also add linezolid 600 Intra Venous eight hourly or oral linezolid 600 mg eight hourly..
Other regimes for MRSA: oral antibiotics Doxycycline 100 and or Sufamethoxazole. Vancomycin can be used in penicillin sensitive patients. For Pseudomonas use Piperacillin + Tazobactam 4gm + 500 mg IV TDS
Usually 2 to 3 weeks of antibiotics cover is good enough when osteomyelitis is not present. If infected (osteomyelitic) bone is removed surgically, then antibiotics course can be significantly reduced.
In renal impairment patients adjustment of dozes is needed in following antibiotics:
- Amoxicillin + clavulanate
- Cephalexin
- Levofloxacin
- Minocycline
- Ampicillin sulbactam
- Cefoxitin
- Piperacillin Tazobactam
- Ticarcillin
- Vancomycin
Renal impairment usually does not need dose adjustment in following antibiotics
- Clindamycin
- Doxycycline
- Linezolid
- Tigecycline
- Moxifloxacin
- Ceftriaxone
Outcome of antibiotic regime
Response to empirical therapy should be assessed after 24 hrs and frequently thereafter. Significant improvement is noticed if proper antibiotics are prescribed along with surgery.
Failure to improve has few reasons
- Resistance to antibiotic
- Missed deeper pus pocket / abscess
- Superadded infection / new infection
- Inadequate doses / and too short duration
- Further deterioration in vascularity ( ischemia)
- Non-compliant patient.
Prognosis:
If the ulcer heals by half in one month, then it is likely to heal completely in 3 months.
Wound management in diabetic foot infections:
When the medical line of treatment and antibiotics are insufficient in management of infected wounds, then need for surgical intervention arises, thus making it a surgico-medical problem.
Surgical drainage, removal of dead tissue (debridement) and amputation are few surgical procedures, which are mentioned in details ahead. Here few examples are quoted, high lightening why and how timely done surgical intervention is crucial for limb and life.
Ascending infection:
*The calf area was grossly contaminated, hence the stump was made smaller and Burgess’ long posterior flap was not suitable. Occasionally surgeons have to alter their decisions in the operative room, in spite of detailed preoperative assessment as was the done here.
Neuropathic – infected – ulcer
When infection is super added in neuropathic ulcer then it would be an infected neuropathic ulcer as seen in this adjacent photograph.
Further spread of infection:
Infection from foot may travel upwards on a number of occasions. It may be considered as deterioration in a few cases. Further details are written ahead at relevant chapters:
Discharge from the wound: dry versus wet wounds
Dry wounds:
Dry wounds are far less common than wet and discharging wounds. But when the wound is too dry it may suggest significant ischemia also.
Wet wounds:
Discharge / exudates from the wound are more common. The discharge could be serous or purulent or blood. Purulent discharge mostly suggests infection, discharge of blood suggests trauma. Blood clots in wounds suggest chronicity of oozing. Discharging synovial fluid indicates that the ulcer has eroded the joint nearby.
Putreous, nauseating, strong odour suggests severe infection. Muddy discharges suggest gram negative organisms, green discoloration of edges suggest pseudomonas, E coli.
A swab should be taken for culture sensitivity. Fungal culture is advised when it is suspected, especially in presence of interdigital mycosis.
Devitalized tissue inside (slough and necrotic tissue):
Quantity and color of slough suggests many things. More the quantity, the more is the tissue involved. A frequent recurrence of slough formation suggests that the devitalization is still going on. Yellow slough is common. It suggests that the resolution is on the way. Black or brown slough suggests deterioration, white slough and pale ulcer indicates that the ulcer has turned into a chronic wound. Many times we get mixed pictures showing both slough and granulation tissue in the same wound. Slough must be removed – it may need a few sittings. In the presence of a slough the wound cannot heal.
Surrounding tissue and infection:
The influence on surrounding tissue depends on the type of ulcer. Neuropathic ulcers when infected have a more distinct effect on surrounding tissue while in ischemic ulcers, the effect is less.
Infections can worsen and can cause gangrene.
Gangrene of forefoot:
Gangrene forefoot and midfoot:
Gangrene of entire foot:
Surgical procedures in diabetic foot
Management of diabetic foot is a surgico-medical task. Many surgical procedures need to be carried out for optimum results. Some surgeries are planned and some are done as an emergency procedure.
Diabetic callus paring / ulcer debridement
Deposition callus in neuropathic ulcers is extremely common. Roughly 10% to 15% of neuropathic patients develop ulcers and calluses at least once! It is one of the commonest surgical procedures in diabetic foot.
How to pare (debulk) a callus:
For easier paring, the callus needs to be stretched by extending toes. The callus is pared layer by layer, till a soft and pliable tissue is visible. Callus paring needs to be done regularly. Paring callus is often done as an office procedure and it needs to be repeated frequently, roughly every 2-3 months. The callus may be kept under control by rubbing it with a pumice stone after bath.
Debridement of callus is done without anaesthesia and usually antibiotics are not prescribed.
Care is taken not to create deep cuts in the callus area. If blade # 15 is held parallel to callus usually deep injuries do not occur. Even if bleeding occurs, cauterization or suturing is not required. Mild compression for 10 minutes usually suffices.
Once the entire callus is excised then the ulcer is more visible. A pus swab can be taken if infection is suspected.
If ulcer edges are undermined then they should be trimmed by holding them with tooth forceps. Base of the ulcer can be scooped gently by an angled scoop, ear scoop or by peanut gauze.
Pre and post operative ulcer measurement is recorded by pictorial diagram and tracing. Size recording is important to decide future line of treatment. Post operative tracing of ulcer on transparent paper and impression is marked on graph paper.
Resident doctors, staff nurses or technicians may be trained to carry out proper or optimum callus paring, under supervision of senior consultants, if the consultant is too busy.
Training for callus paring can be done on a sweet lime (”musambi”) . Hold the knife parallel rather than vertical for correct debulking. Mostly it is removed piecemeal rather than in “one chunk”. We have included this procedure in all our workshops.
Instruments required for callus paring and ulcer debridement:
Few examples of callus paring and few common sites of callus:
Paring callus:
Callus paring
Debridement:
Definition: (Merriam-Webster dictionary) : It is surgical removal of damaged, lacerated, devitalized (dead), contaminated tissue, foreign body from a wound. It is also known as sharp debridement. This term was used for the first time by Circa in 1842.
Debridement helps in healing and it is the most commonly done surgical procedure in diabetic foot management.
However apart from surgical debridement there are other forms of debridements too. Such as:
1) Mechanical 2) Chemical 3) Autolytic 4) Biological (maggots) 5) VAC
Surgical debridement is done by surgical instruments like scalpels, scissors and scoops. Sometimes lasers are used, but they are not popular. Surgical debridement is most effective and quickest amongst all types of debridements and hence it should be preferred.
Principles of surgical debridement
Debridement is the most commonly done surgical procedure in diabetic foot treatment. Often it is done as bedside procedure or in dressing room, but ideally it should be done in operation room, under proper conditions such as asepsis, good light source, comfortable position for both patients as well as surgeon and with trained assistance.
Modern day concept of minimally invasive or “buttonhole” surgery has no role in diabetic foot debridement surgery. The debridement surgery should be bold, wide and under direct vision. Though it is should be bold and aggressive, the tissue should be handled gently.
The Iceberg!! The infection is a diabetic foot could be as deceptive as an iceberg where much more is hidden than revealed.
As far as possible most of the debridement should be done in one sitting and smaller further debridements may be done as and when required.
Neuropathic feet: debridement must be bold!!
During debridement all areas of the must be explored especially, underneath the edges, to see if there is any slough hidden.
Debridement of dorsal wounds:
Compared to plantar wounds the outcome of dorsal wounds debridement is significantly better, mainly because there is no weight on dorsal wounds. Secondly, dorsal lesions are visible hence the wounds are noticed much earlier, so treatment is sought earlier, giving better results.
The tendons are retained till they show tensile strength. Exposed tendons should be kept protected from desiccation (drying). Surprisingly they survive difficult conditions.
In this patient excision of devitalized extensor tendon of little toe was done when its insertion was detached. No significant extensor deformity was noticed in spite of healing by secondary intention.
Debridement of plantar wounds:
The plantar wounds do not heal easily. The debridement on the plantar surface should be more conservative. The plantar skin is precious because it is meant for weighting.
This patient was treated at a village (rural) hospital for this plantar wound for two years. The heel wound did not heal. Why? Here are a few reasons why plantar wounds do not heal easily.
- The planter skin is tough, but so is the healing. There is plenty of fat underneath this thick, hairless skin. It can accumulate a significant amount of infected material in its spaces without revealing what it is hiding (too secretive?)
- There are 109 ligaments, collaterals, joint capsules and avascular plantar fascia and a thick layer of plantar fat making it more vulnerable for poor or delayed healing.
- The asset can become troublesome! The thicker and sturdy plantar skin does not rupture easily (an asset), inspite of accumulation of plenty of purulent devitalized tissue. Had it ruptured easily it would have given an outlet to this purulent collection.
- Lastly, the most important reason is that we put our body weight on the plantar aspect. This aggravates the damage. Because of weight, the neo-epidermis, neovascularization and collagen binding is repeatedly damaged and the healing process is grossly delayed. Hence offloading, removal of weight from plantar skin is immensely important.
This line diagram is showing the weight bearing area of the foot. The Incision on weight hearing area of plantar aspect should be avoided if possible. Incisions on “instep”, lateral and medial borders are preferred as they do not lie on weight bearing areas.
Communicate the wounds:
If there are small skin bridges they should be divided, so that one large wound is created (instead of many smaller wounds see photo below). Smaller but unopened wounds may hide devitalized tissue, while larger but open wounds are less likely to hide.
Note an infected ulcer on the great toe. The infection has trickled down along with flexor tendon stealth upto “instep” (mid foot) area. An incision is taken all along flexor tendon sheath to drain infection and to avoid tendon necrosis. I would like to call it “a preempt” surgical approach to remove infection by creating an outlet.
Posterior, medial and lateral wall debridements:
Debridement on lateral, medial and posterior heel areas may be carried out aggressively like dorsal wounds.
In this patient also infection has entered the hind foot through fissures and caused skin necrosis. Linear fasciotomy along Achilles tendon was done. Infected material was drained. Partial excision of heel pad needed. The wound was prepared and closed by a skin graft after a fortnight. The wounds healed well.
Debridement of web spaces:
The first web space is most vulnerable for wounds and infections, often because of a “chappal” (the most common footwear in India). Other web space infections are less common and often occur due to poor hygiene. Infection in web space shows high incidence of gangrene in both adjacent toes, unless adequately treated early.
How much tissue should be excised during debridement?
Ideally all devitalized tissue should be excised during debridement and thus keeping only viable tissue. The viability of tissue is judged (usually on the operation table) by appearance of tissue and vascularity.
Mostly it is a clinical judgment of a surgeon, who decides what to retain & what to excise. This judgment is quite straightforward in most of the situations, but is difficult in borderline situations, because the tissue may survive or may not survive.
Though it is not hard and fast rule, we follow these guidelines on most of the occasions
- If the excised tissue can be replaced easily by a graft or a flap, then excise it more boldly. Eg: Dorsum of foot.
- If the tissue is covering important structures such as posterior tibial artery or bones or tibialis anterior tendon or so, then be more conservative. Retain the tissue which is doubtfully surviving. If it does not survive, it can be excised at a later date.
- Survival of tissue is doubtful? No important structure beneath? Then debride completely.
- Survival of tissue is doubtful? But an important tissue present underneath? Be conservative in debridement.
- Delayed or staged debridement can be planned; this is especially true in distally based, avulsion flaps on plantar aspect. The distally base avulsed flaps may show line of demarcation after a few days. Debride then.
Debridement and ulcer offloading by dorsal approach:
Vinay Saoji’s (author’s) modification:
Because of sustained weight on a bony prominence an ulcer (often with callus) can result. This ulcer often occurs on metatarsal heads, as written in intrinsic ulcer mechanism. The ulcer which lies on a bony prominence often does not heal because the tissue is trapped between bony projection and ground when patient stands or walk.
The aim of this surgery is to remove this bony prominence, by dorsal approach. Though excision of this bony prominence can be done by a plantar approach, it is not recommended as incision would be on weight bearing area. The dorsal approach may be considered, if a bony prominence is too prominent and is causing repeated ulceration. The author has been practicing this technique for many years. If there is high probability of a plantar ulcer then this procedure was also done as “a preemptive surgery”.
This was regarding surgical debridement. A brief outline of other ways of debridement is mentioned here.
Mechanical debridement: It is actually a frequent change of dressing. Every time a dressing is changed the outer and loose dead tissue is peeled off, thus creating a healthier wound. After cleaning with saline, iodine soaked gauze is applied to the wound and allowed to dry for a day or two. When this dried dressing is peeled, it causes mechanical debridement.
Chemical debridement (Enzymatic debridement):
Here few chemicals are used for debridement, mostly these chemicals are Colagenase, papain. The source could be: animals, plants or bacterias (clostridium histolyticum).The chemicals and diluted H202 is applied, once or twice a day. The results are mixed and inconsistent hence chemical debridement is not very popular.
Autolytic debridement
Here the body’s own enzymes are allowed to soften/ liquefy the dead tissue and eschars. These enzymes are reliably selective and only devitalized necrotic tissue is liquefied. This kind of response is often seen in bed sores. (See the figure below.)
Usually semi occlusive or occlusive dressings are used with hydrogels, hydro colloids to maintain hydration (moisture). Though it is painless, it is the slowest technique and is not ideal for large and infected wounds.
Biological Debridements: Maggots
Larvae (maggots) of green bottle fly feed only on dead tissue. This property of feeding only on devitalized tissue is used by some clinicians for debridement. Sterile (I don’t know how to make them sterile) larvae are put in the wound for debridement. This is also called “larval therapy”!!
We (more so I) strongly oppose this method. As a surgeon I hate to see these crawling, creepy creatures in the wound, especially when we follow high standards of asepsis.
In fact, whenever we see maggots, we remove them (it is an unpleasant job and our OT staff don’t like it). So also all my patients hate this suggestion of therapy out right. “No, No!! Don’t put worms in my wounds!!”
Photograph is showing maggots in a diabetic foot ulcer. Isn’t it a poor (eek!) sight?
This patient came to our hospital, absolutely shaken, when he saw these creatures in the wound. How can a patient accept this as one of the “treatment”?
NPWT (Negative Pressure Wound Therapy) or VAC (Vacuum Assisted Closure) procedures:
When infected wounds secrete significant infected material, then primary wound closure may not be recommended. Such wounds can be improved rapidly by Negative Pressure Wound Therapy (NPWT). It is popularly known as VAC therapy.
It is a briefcase sized device, with a vacuum (suction) pump. this suction is attached by a tubing to foam dressing. There is a canister for collecting the fluid that is sucked out.
VAC with irrigation In another variety wounds can be irrigated through an inlet and secretions such as purulent material are sucked out through an outlet.
Here are few models:
How is VAC applied?
The wound is cleaned and non-adherent dressing is applied. The wound is filled with foam which is cut to the size of the wound. Wounds can be covered with Hyaluronic acid if bone and or tendon are exposed. The wound is sealed by a transparent film.
Drainage tube is connected to foam by making a small window in the film. Once dressing sealed the device can be set on continuous suction mode or intermittent mode. The negative pressure can be set anywhere in between 40 (weak) to 200 (strong sucking force).The pressure is adjusted as per requirement (and patient’s tolerance.).
The advantages are: 1) patients can move with a pump and there is no need to change dressings daily 2) Once applied It can be kept for 5-8 days. 3) The negative pressure also increases blood flow in the wound.
Photo shows VAC being applied. Note: the canister is filled. Note a healthy wound after VAC
Fig 1 to 5: This patient had undergone amputation of second gangrene sometime ago. Now he developed gangrene of right third toe with purulent collection in the midfoot region and deep plantar space involvement. Wedge amputation was done and plantar spaces were debrided. A VAC was applied. The vac was left in situ for 8 days. The wound showed significant improvement and was closed later.
VAC contraindications
- Bleeding wound
- Exposed vessels, vascular anastomosis
- Malignancy wound
Precautions: 1) VAC should be removed immediately if there is sudden bleeding.2) If the fever is more than 102 F.
Skin grafting and flaps:
On many occasions the skin cover is lost in diabetic foot. The reasons are many, but the commonest is devitalization due to infection needing debridement.
Larger wounds need either skin graft or a flap for closure of the wound. Local flap options are less especially distal to the ankle. In ischemic foot the vascularity is compromised and incidence of wound dehiscence or non- healing is higher. Micro-vascular or free flap options are very few in view of calcified vessels. The patient is often not medically fit for prolonged surgical time for free flaps, so also expertise may not be available. That leaves skin grafting as the most logical option. Surprisingly the skin grafts do well in various situations. We have given few common indications for skin grafts and flaps ahead.
Example of skin grafting # 1:
Example of skin grafting #2 :
Skin grafting # 3:
Skin grafting case #4:
This neuropathic patient had wounds over lateral aspect and dorsum of the foot. The wound was covered with a dry eschar when we saw him first. The wound needed debridement, few dressing and skin grafting.
Skin grafting case # 5:
Skin grafting case # 6:
Here are a few other examples of skin grafting. All wounds had healthy granulation tissue. Such wounds can “accept” skin graft quickly and well. Fasciotomy wound closure by skin grafting is far easier than secondary suturing.
Is skin graft too thin? Ulcerates often? Then “over grafting”, may be the answer.
Weight bearing on skin grafts can cause ulceration. Repeated ulceration can be prevented by doing “over grafting”. In this surgery, epidermis from old skin graft is removed by shaving or abrading it. The resultant raw area is covered by a thicker skin graft. The skin graft almost always “takes up” in such wounds. The author does this procedure whenever an occasion arises.
Flaps:
The bursa may or may not be communicating with the ankle joint. If the bursa is communicating with the joint cavity, then it may cause septic arthritis. The ankle could be unstable. In such a situation the anterior talofibular ligament may need repair, reinforcement or augmentation.
Author’s technique for lateral malleolus bursitis:
Bursectomy and debulking
The overlying skin is almost always hardened; thickened like a callus and sometimes there is a sinus. In such a scenario we treat this deformity something like a carbuncle by taking a cruciate incision as shown here.
The four flaps are then put back at their respective position and the wound is closed by a purse string suture or loose sutures or allowed to heal by secondary intention.
If the bursa is communicating then the tract or window is closed by sutures. Sometimes it is not possible to close the joint capsule or the defect because of tissue deficiency, then it can be patched by tensor fascia lata graft or the wound can be covered by flap. Both options give fairly good results.
Cruciate incision: lateral malleolus bursa: example # 2
Advantages of author’s Vinay Saoji’s four flap technique
The four flap technique gives good exposure hence excision is relatively simpler.
Since excision is complete the recurrence rate is significantly less.
This procedure can be done in smaller hospitals too.
It is less expensive than endoscopic excision.
Lateral malleolar bursitis and callosities: Lazy “S” incision approach: example 1
Lateral malleolus Bursectomy: Example # 2:
Lateral malleolus Bursectomy: example #3:
Lateral malleolar infections: skin grafting: example # 1
It is not rare to see severe infection around lateral malleolus where debridement and skin grafting is needed. Here are a few examples.
Lateral malleolar infections: skin grafting: example # 2
Lateral malleolar infections: skin grafting: example # 3
Infection in Achilles tendon
Heel wounds and infections do not heal easily
Even a small skin loss or a defect cannot be closed by primary approximation and needs a skin graft or a flap as shown below.
The heel wounds and infections:
Here the calcaneus needed radical (extensive) excision. A counter incision was taken on the lateral border to facilitate drainage of purulent material. More priorities may be given to plantar wound healing because it is the weight bearing area.
The heel wounds and infections:
The heel wounds and infections:
This diabetic foot patient sustained a thorn injury. The attempt was made by the patient to remove it at home with a safety pin and eyebrow plucker. The thorn broke and was left inside the wound for a few months. This chronic wound with odour was explored widely. The osteomyelitic calcaneus was gouged (scooped) completely and the wound was closed by undermining.
The heel wounds:
The heel wounds:
Shin wounds:
Infection from an infected diabetic foot may ascend upwards over the shin. This may cause osteomyelitis, discharging wounds and sinuses.
Fasciotomy and Decompression Surgeries:
Lateral compartment syndrome
Accumulation of edema fluid, infected material (pus), bleeding and haematoma in the osteofascial compartment makes the area tense. The interstitial pressure rises, causing vascular occlusion leading to muscle necrosis and systemic changes such myoglobinuria, acute renal shutdown; septicemia, toxemia and gangrene. The damage is irreversible, if the pressure is not relieved quickly.
Causes
Trauma, especially closed fracture of tibia-fibula with vascular injury, crush injury, is the commonest cause.
However, an almost similar picture though may not be of same magnitude, can be seen in diabetic foot, especially with severe cellulitis and deep infection. This is not uncommon. This tense, tight limb leads to a lesser version of tight compartment syndrome.
Fig. 1: Non Traumatic “Tight Foot Compartments”: Left foot dorsum shows blisters, congestion and devitalized skin.
Compartments of foot and leg
The compartments in leg are often discussed and managed but, somehow or the other, foot compartments are not that adequately treated as they should be. This is often because the compartments in foot are not so well highlighted in medical practice.
There are nine compartments (spaces) in the foot; 4 major and 5 minor. The 4 major spaces are: medial, lateral and two central.
Surgery: decompression and fasciotomy:
Fig 1, 2: Schematic line diagram showing two approaches to reach spaces in the foot. These compartments are overlapped and for surgical intervention or for decompression or fasciotomy they are not easily distinguishable
In many diabetics the foot and the limb below the knee becomes grossly swollen and tense. The picture mimics tight compartment syndrome, but without trauma
We, (rather I) practice decompression; as an emergency primary procedure in such a situation. We have searched many books, journals but there is not much material, literature or data available in this context.
I think this procedure needs more studies, long short follow-ups & scientific analysis, so that it would get more recognition and more takers.
Fasciotomy and decompression of lower limb and foot, needs to be carried out more often, while managing the diabetic foot.
Severe infection, marked oedema and tense limb is quite common in clinical practice. Mostly they present quite late. Sometimes the blisters are seen. Usually there is a leaking/discharging wound on the foot.
The temperature is often raised in contrast to cold limbs due to trauma.
Patient is often in septicemia (with a toxic look). There are signs and symptoms of significantly severe infection.
Definition: Fasciotomy is a surgical procedure where fascia is cut open (and partly removed), to relieve tension or pressure.
Decompression is almost the same as mentioned above though the deep fascia is not so distinct in web spaces, insteps and plantar spaces . We decompress these limbs as early as possible, mostly within a few hours of consultation.
Fasciotomy in Infective foot and the lower limb often gives dramatic results because the bacterial load in the limb gets dramatically reduced as the pathological contaminated fluid is drained. Also reduction of pressure helps in prevention of muscle, nerve necrosis. The renal necrosis is prevented.
The common sites of doing fasciotomy are in descending order are
1 ) lateral compartment release fasciotomy , 2) lateral foot, 3) Dorsum of foot ,4) Medial aspect of foot, 5) Medial aspect of leg, 6) Lateral aspect of thigh, 7) Foot : plantar aspect 8) Multiple fasciotomies
Lateral leg decompression
Lateral foot decompression:
Dorsum of foot fasciotomy/decompression
Medial fasciotomy of leg, lateral fasciotomy of thigh:
Plantar decompression:
Fig. 1,2,: Plantar decompression. Note purulent collection over instep area. The flexor tendon sheath laid open up to the midfoot.
Combined fasciotomy: lateral and medial
Combined fasciotomies: medial and posterior fasciotomy.
Combined fasciotomies: oblique dorsal and medial fasciotomies
Combined fasciotomies: web and dorsum of foot
Fasciotomy combined with skin excision /debridement:
Debridement and fasciotomy:
Fasciotomy combined with amputation:
Decompressive fasciotomy: salient points of surgery
After decompression, surrounding areas are squeezed to remove seropurulent, infected fluid. All the septae and barriers are broken by index finger, sinus forceps or careful use of scissors.
Usually haemostasis is achieved by electro-cautery, ligation of larger bleeders and compression. So many times the patient is on anticoagulants or aspirin in that case more care is desired in haemostasis.
The cavity is then packed with tulle gras, impregnated with antibiotics (Bactigras) for smooth removal afterwards. We sprinkle chloramphenicol powder or solution in the wound. Occlusive dressing is applied.
Sometimes the decompression is done in stages. As a first stage procedure the limb is decompressed as early as possible, even if sugar levels are high. This decompression helps in bringing blood sugar levels under control much faster.
More detailed and elaborate debridement is done, when the patient is further evaluated and diabetics under better control.
Fluid or drained contents should be sent for bacterial culture and till the reports are available empiric antibiotics are started. Definitive antibiotics started after reports are available.
Closure of fasciotomy and decompression wounds
A fasciotomy wound can be closed when edema of the limb becomes less and when fasciotomy has served its purpose. There are two options for fasciotomy wound closure: 1) conservative (by dressing) 2) by surgery.
Option 1 Conservative: The wound may be allowed to heal with secondary intention and meanwhile the dressing is continued. But this option is good only for smaller wounds. Larger wounds often need some surgical intervention.
Option 2) Surgery: closure of fasciotomy by secondary suturing:
Fasciotomy was done immediately on admission. The wound was closed by suturing at a later date.
Closure of fasciotomy by skin graft:
Fig. 1: Fasciotomy wound has been closed by skin graft.
Closure of fasciotomy by skin graft:
This patient had an infected wound and skin devitalization had occurred before admission. He required decompression fasciotomy, debridement, wound preparation and skin grafting.
Closure of multiple and complex fasciotomy wounds
Inadequately done decompressions:
Inadequate releases by small incisions often do not serve the purpose. So decompression should be done adequately.
Results
When this procedure is done in time and adequately, then reduction in morbidity and complications due to septicemia are significantly less.
We are quoting one non diabetic patient’s case study to just highlight the importance of timely and adequate decompression for optimum results.
This 34 year old NRI lady met with an accident while she was on holiday in India and sustained mildly displaced fracture tibia, middle third segment. She was treated in a nearby orthopedic hospital and was shifted to our hospital on the fourth day when her condition rapidly deteriorated.
Photos on admission show blisters, congested skin, a small fasciotomy incision and popping out muscle. The peripheral pulses were absent. The limb was firm, tense but cold. Patient earlier was probably non diabetic but now showed high blood sugars,>300mg and needed insulin.
Patient was critically ill and in shock. Immediate decompression by lateral and medial fasciotomies was carried out. The patient started showing rapid improvements on all fronts, general and local.
Status on tenth day: the limb survived but extensive debridement of devitalized muscles was needed. The major vessels were protected carefully during surgery. Packing and daily dressing, under sedation, were carried out. Renal parameters started becoming normal and the patient became more cheerful.
The status on 20th day: collateral circulation improved well. Now dressings were done on alternate days and antibiotics tapered.
Status on 40th day
Status after 40 days: wounds were closed by loose secondary sutures.
Status after six months: fractures healed and patient could walk with a foot drop splint and rejoined her old job at Singapore. She is off anti-diabetic medications.
Infection causing Macrodactyly:
Macrodactyly of the toe (enlarged toe) is fairly common in diabetic feet. Usually the great toe is involved. The toe is grossly enlarged due to chronic infection and fibrosis. Usually it takes months or a few years for deformity to occur and before the patient seeks advice.
The hallux is firm because of chronicity. The skin is fibrotic and thickened. The nail is distorted, thickened and hypertrophic. X rays may show enlarged bony phalanx, marked bony destruction; osteomyelitis and few discharging wounds. Amputation is often advised and most of the patients and relatives plead to salvage the toe.
Author’s technique:
These patients are often advised amputation either partial or total. The advice is justified because it is clinically based too. The radiological picture, the culture reports also support it. But the problem is the patient’s reluctance for amputation.
We often face this scenario in our clinical practice – the moment we suggest that a patient needs an amputation of a toe, the patient gets nervous. Then a request comes “Please save my great toe. How would I walk? How would I wear my “Chappals?” “Pleeease do something.”
Well here is “that something” I prefer to do.
We have searched books, literature and “surfed the internet” but there is hardly any mention in this regard).
The edges of the ulcer are freshened. Haemostasis is achieved and the wound is irrigated. Both flaps are then inspected for vascularity. Sometimes trimming may be required.
Few approximating sutures are required to hold the flaps in position. Posterior splint is applied for giving rest to the part.
Surprisingly in a large number of patients the residual (debrided and filleted) toe does not become as flail as anticipated after surgery, especially where fibrosis exists.
A special precaution is taken to avoid button holes in the nail bed complex. If a buttonhole happens then it is repaired by fine sutures. Here are few examples of the procedure I do:
Macrodactyly: case 1:
Macrodactyly: example #2
Macrodactyly : example # 3
Left hallux macrodactyly
“Telescoping” of toes
Author’s technique:
The indications are almost the same as mentioned in the previous topic of Macrodactyly and ‘Fish Mouth” technique surgery. Usually we do this “telescoping of toe surgery” to salvage at least a significant part of the great toe. In both, previous and this technique, the head of the first metatarsal is not excised, hence weight bearing is not disturbed.
Fig. 1: Photograph showing long telescope, when folded it becomes small. Similarly macrodactylus’ long great toe looks shrunken; hence I would like to call it “telescoping of toe”.
Short Notes in Plastic Surgery 