Gangrene of the foot
Last reviewed: 23.04.2024
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How often does gangrene stop?
Obliterating diseases of the arteries of the legs affects up to 2% of the world population, in the overwhelming majority of men. Gradual progression of pathology within 5 years leads to critical lower limb ischemia in 10-40% of patients. The mortality rate varies between 6-35%.
In 30-60% of cases, the cause of gangrene is acute occlusion of the main arteries, lethality at the same time reaches 45%. Mortality in limb necrosis caused by ileofemoral phlebothrombosis, a rather rare but extremely severe pathology, reaches 60%.
What causes gangrene of the foot?
Gangrene of the foot characterizes the terminal stage of chronic arterial insufficiency of the legs. To it lead gradually progressive diseases of the main arteries. Sudden occlusion of the arteries of the lower extremities with their embolism or thrombosis leads to acute ischemia. The development of contracture in the joints indicates the death of muscle tissue. At morphological research in such patients necrosis of fabrics of legs is found out, despite of absence of external attributes of a gangrene.
Ileofemoral phlebothrombosis, which proceeds with the development of the so-called blue phlegmase of the limb; disturbance of blood flow through small "non-vital" vessels (for example, in diabetes mellitus and various arteritis), trauma (mechanical, thermal, chemical) of distal legs - all this also leads to destruction and tissue necrosis. The outcome of the disease can be not only the loss of the leg, but the death of the patient against the background of intoxication.
What kinds of gangrene does the foot have?
Depending on the reaction surrounding the necrotic focus of the tissues, moist and dry gangrene of the foot are secreted.
Hyperemia, swelling of the tissues around the necrotic masses in combination with a characteristic fetid odor are inherent in a moist form. As a rule, its development is provoked by putrefactive microorganisms.
How is gangrene recognized?
When examining a patient who has gangrene of the foot it is important to determine the leading cause of its development, and also to assess the viability of the leg tissues at different levels. After all the studies, it is necessary to solve the problem of the possibility of performing limb revascularization in order to prevent the progression of necrosis.
For arterial insufficiency, numbness and constant pain in the legs, which decrease when it is lowered, are typical. The presence in the anamnesis of gradually increasing intermittent claudication is characteristic for obliterating thromboangiitis or nonspecific aorto-arteritis at a young age, and in the elderly for obliterating atherosclerosis. Sharp cooling of the legs, a violation of sensitivity and motor activity is noted in embolism or thrombosis of the main arteries of the legs. Rapid development of edema is typical of phlebothrombosis. Moderate pain localized in the zone of necrosis is characteristic of diseases based on microcirculatory disorders.
When examining the patient with gangrene of the lower limb, attention should be paid to its position. So, for a patient with decompensated arterial insufficiency, the position of sitting on the bed with the lowered leg, which he periodically rubs, is characteristic. Conversely, with venous pathology, the patient, as a rule, lies with an elevated lower limb.
The etiology of necrosis can also be judged by the appearance of the limb. Hypotrophy, absence of hair cover, fungal lesion of nail plates are characteristic signs of chronic arterial insufficiency. Swelling and cyanosis or paleness of the legs are typical for acute venous or arterial insufficiency, respectively.
Cold covers on palpation indicate ischemia of the limb. The key stage of clinical examination of a patient with trophic disorders is the determination of arterial pulsation on the affected limb. If the pulse is determined in the distal parts, then the pathology of the main blood flow can be excluded. The absence of a pulse at typical points (under the inguinal fold, in the popliteal fossa, at the rear or behind the medial malleolus) indicates an arterial insufficiency. For severe ischemia, the contracture is typical in the ankle or knee joints.
Gangrene stops requires standard tests for surgical patients:
- general blood analysis;
- blood chemistry;
- determination of blood glucose level.
Necessarily, a microbiological study of necrotic focus with the determination of the sensitivity of microflora to various antibacterial drugs.
Instrumental examination of the patient is advisable to begin with ultrasonic duplex angioscanning. This method allows you to answer a few basic questions.
- Is there a significant pathology of the major vessels of the legs?
- Is surgical revascularization possible?
- Is occlusive-stenotic lesion of the main arteries accompanied by marked hemodynamic disorders?
The last question can be answered by measuring the systolic pressure on the main arteries in the lower third of the shin using ultrasound Doppler study. The systolic pressure on the tibial arteries is below 50 mm Hg. Or an ankle-brachial index of less than 0.3 indicates a critical ischemia of the distal legs. Angiography in patients with gangrene is justified only in the preparation for surgical intervention on the vessels.
One of the most informative methods for assessing the state of tissue blood flow in gangrene of the legs is scintigraphy with 11Tc-pyrfotech. This radiopharmaceutical has tropism for bone tissue and necrosis foci (especially with perifocal inflammation). After 2.5 hours after intravenous administration, the isotope distribution in the legs was evaluated. The level of accumulation of 11Tc-pyrfotech in the affected limb is less than 60% of that in the contralateral "healthy" limb is considered low, indicating severe ischemia.
Laser Doppler flowmetry allows you to accurately determine the degree of disturbance of tissue blood flow. In addition to basal blood flow, it is necessary to determine its response to functional tests: postural and occlusive. In critical ischemia, basal blood flow has a characteristic monophasic low-amplitude appearance; the reaction to the postural sample is inverted, and the occlusal sample is severely retarded.
Patients who have gangrene of the foot, developed against a background of systemic disease (for example, obliterating atherosclerosis, diabetes, arteritis), it is necessary to consult a therapist, cardiologist, neurologist and endocrinologist. Sometimes a consultation of the gastroenterologist is required, since 30% of patients who have gangrene of feet on the background of critical leg ischemia reveal erosive and ulcerative lesions of the upper gastrointestinal tract.
Gangrene stops differentiating with the following diseases:
- with severe dermatitis;
- with a necrotic form of erysipelas;
- with the syndrome of positional compression.
The diagnostic algorithm includes an assessment of the condition of the legs and other organs and systems. The clinical and instrumental examination of the patient with gangrene of the lower limb should result in a clearly formulated diagnosis reflecting, in addition to the condition and prevalence of the necrotic focus, the nature of the underlying disease.
How is gangrene treated?
The goal of the treatment is the elimination of the purulent necrotic focus and the subsequent complete healing of the wound. The desire for maximum preservation of the limb is a postulate of modern surgery.
Out-patient treatment is possible with local necrosis due to microcirculatory disorders. The pathology of the major vessels of the limb, complicated by necrosis, is an indication for hospitalization.
Drug treatment is aimed at improving tissue flow, and with symptoms of intoxication - a complex, including antibacterial, anti-inflammatory and detoxification therapy. When prescribing antibiotics, it should be borne in mind that in all patients with long-standing necrosis, the regional lymphatic system is infected. And the microbiological study of popliteal and inguinal lymph nodes, performed in 20-30 days of inpatient treatment, reveals, as a rule, the same microflora that was in the zone of trophic disturbances at the time of hospitalization. Thus, antibiotic therapy in such a condition as gangrene of the foot is long and is prescribed taking into account the sensitivity to the preparations both existing in the wound microflora that is being separated (if it exists) and microorganisms detected in the necrotic focus during hospitalization.
The amount of surgical intervention depends on the size of the necrotic focus, the features of regional hemodynamics and the general condition of the patient.
The development of necrosis against the background of microcirculatory disturbances with the preserved main blood flow in the distal sections of the legs allows us to confine ourselves to radical necretomy with the application of a drainage-flushing system (or without it) and the primary suture of the wound.
Satisfactory perfusion of the surrounding necrotic tissue focus, even against the backdrop of violations of the main blood flow - the basis for minimizing the amount of sanitizing intervention (only necrotic masses are removed). When doubting the viability of the remaining tissues, the primary sutures do not overlap, leaving the wound open.
Patients who have gangrene of the foot against the background of limb ischemia should take into account the severity of the general condition, since vascular interventions in decompensated concomitant pathology are characterized by a higher mortality rate than primary amputation at the femur level. When choosing the extent of intervention in patients with critical ischemia, it should be assessed whether the support function will be retained in the case of hemodynamically effective revascularization. Indications for amputation at the level of the leg or thigh:
- total gangrene of the foot;
- necrosis calcaneal region with the involvement of bone structures;
- occlusion of the distal part of the arterial bed of the legs.
When choosing the level of intervention, one should focus on the clinical picture of the disease and the data of the instrumental survey. Thus, in acute vascular pathology (embolism and thrombosis of the main arteries, thrombosis of the main veins), amputation is performed 15-20 cm above the proximal border of the clinical manifestations of ischemia. Determination of tissue blood flow in various limb segments allows performing amputation in the area of satisfactory microcirculation.
Surgical tactics for chronic arterial insufficiency of the legs, complicated by necrosis, has a differentiated character. A direct revascularization of the lower extremity is indicated when the volume of destruction and subsequent necrosis allows to rely on the preservation of the supporting function and there is a distal arterial channel suitable for reconstruction. It is advisable to perform both the hearth repair and vascular reconstruction simultaneously. Guillotine necretomy is the optimal volume (minimal, since the additional trauma of ischemic tissues leads to the progression of necrosis), simultaneous with the vascular reconstruction of the sanitizing intervention. In the future, the wound is openly.
According to the instrumental research methods, the maximum restoration of tissue blood flow occurs one month after hemodynamically effective vascular reconstruction. That is why repeated intervention on the foot, combining, as a rule, stage necrectomy and plastic closure of the wound, it is advisable to perform not earlier than a month after revascularization.
Methods of surgical treatment
Exarticulation of the finger
The gangrene of the foot and the distal phalanx of the finger against a background of satisfactory tissue blood flow in the foot is the main indication for the operation. Cut out the rear and plantar skin-subcutaneous-fascial flaps. The capsule and lateral ligaments of the interphalangeal joint are dissected, turning the main phalanx to the dorsal side. It is necessary to try not to damage the articular surface of the metatarsal head. After removal of the bone structures, primary seams are applied and, if necessary, the wound is drained.
Amputation of fingers with metatarsal resection of metatarsal bone
Indications for surgery - gangrene of the foot and distal and main phalanges of the finger against a background of satisfactory tissue blood flow in the foot. Cut out the rear and plantar skin-subcutaneous-fascial flaps. Gila's saw cross the metatarsal bone proximally to the head, the sawdust is treated with a rasp. Isolate and maximally cross tendons of muscles - flexors and extensors of a finger. Complete the operation by imposing primary sutures and draining (or without it, depending on the clinical situation).
Amputation by Sharpe
Indications for surgery - gangrene of the foot and several fingers against a background of satisfactory tissue blood flow in the foot. Cut out the rear and plantar skin-subcutaneous-fascial flaps.
Isolate and maximally cross the tendons of the muscles - flexors and extensors of the fingers. Separately, the metatarsal bone is sawed out and sawed in the middle, the sawdust is processed with a rasp. Complete the operation by imposing primary sutures and draining or dispensing with it, depending on the clinical situation.
Amputation by Chopar
Indications for surgery - gangrene of the foot and fingers, passing to the distal part against the background of satisfactory tissue blood flow in it. Two fringing incisions are made in the region of the heads of metatarsal bones.
Allocate metatarsal bones. Tendons cross as high as possible. Amputation is performed on the line of the transverse joint of the tarsal (Shoparova) with preservation of heel, talus bones and part of the metatarsus. The cult is closed with a plantar flap immediately or after the inflammatory process subsides.
Amputation of lower leg
Indications for surgery - gangrene of the foot against a background of satisfactory blood flow to the shin and low - in the foot. Cut out two dermal-subcutaneous-fascial flaps: a long posterior and short anterior, 13-15 and 1-2 cm, respectively.
In the transverse direction cross muscles around the fibula, secrete and cross the peroneal nerve and vessels. The fibula of the fibula is produced 1-2 cm above the level of the tibial intersection. The masochistomy along the line of dissection is displaced only in the distal direction. First sawed fibula and then tibia. Isolate and ligate the anterior and posterior tibial vessels. Dissect muscles. In connection with the peculiarities of the blood supply, it is advisable to remove the soleus muscle.
Tailings of tibia bones are processed, soft tissues are sewn without tension, leaving a tubular drainage for active aspiration on the bottom of the wound.
[15], [16], [17], [18], [19], [20]
Amputation of the hip
Indications for surgery - gangrene of the foot against the background of low tissue blood flow in the foot and shin. Cut out the front and back dermal-subcutaneous grafts.
Isolate and ligate a large subcutaneous vein. They dissect their own fascia of the thigh, mobilize and cross the tailor's muscle. Then the superficial femoral artery and vein are exposed. Vessels are mobilized and, after being bandaged twice, are dissected. In the posterior group of the thigh muscles, the sciatic nerve is isolated, infiltrated with an anesthetic solution, tied with a resolving fiber and cut as high as possible. After that an amputation knife is crossed by the anterior and posterior groups of hip muscles. The nude femur is cleaned from the periosteum in the distal direction by a rasher and after a proximal retraction of the muscles by a retractor is re-sawed.
Sharp edges of the sawdust are processed with a rasp, rounded. Carry out a thorough hemostasis in the intersected muscles, then they either stitch, or not with their puffiness, poor bleeding, dull color). Necessarily overlap the fascia and skin, leaving under the fascia and muscles tubular drainage for active aspiration.
Postoperative complications
The main postoperative complication in patients who have gangrene of the foot is the progression of limb necrosis, which is associated, as a rule, with an error in the choice of the intervention level. So, amputations (against the background of arterial insufficiency) require re-amputation in more than 50% of cases; at the level of the shin - in 10-18%; femora - only in 3% of patients. With the development of wound complications (suppuration, necrosis of the edges of the wound), repeated interventions are often required. Prolonged non-healing wounds, as well as protruding from soft tissue bone fragments - indications for re-amputation. However, it is important to remember that mortality rates for re-appeals are always higher than those after primary interventions at the same level.
In patients who have gangrene of feet in the background of atherosclerosis, acute myocardial infarction or acute disturbance of cerebral circulation often develop. To reduce the risk of these complications allows anticoagulant therapy with low-molecular heparins. A sharp decrease in motor activity with loss of support function, especially in patients with severe concomitant pathology, often leads to the development of hypostatic pneumonia.
Prolonged pain syndrome, chronic intoxication, uncontrolled intake of tableted analgesics and non-steroidal anti-inflammatory drugs in the preoperative period, traumatic intervention - all this predetermines the frequent development of both chronic and acute ulcers of the stomach or duodenum with subsequent bleeding or perforation. This is why all patients with critical ischemia of the lower limbs should prescribe drugs that oppress the production of hydrochloric acid (HCl) during the entire treatment period.
Early activation of patients is desirable. After various amputations, you can get up and walk already in the first day of the postoperative period. With the stored support function, it is necessary to reduce the load on the limb, for which crutches are used. With a favorable course of the wound process, the sutures are removed 10-14 days after the operation. Longer treatment in the hospital (1.5-2 months) is passed by patients who have undergone limb revascularization and necrectomy, as the tissue blood flow in the foot is restored gradually.
How is gangrene prevented?
Gangrene stops can be prevented if timely detection of vascular pathology and the appointment of adequate treatment.
What prognosis is gangrene of the foot?
Gangrene stops has a different prognosis. It depends primarily on the cause, as well as the cutoff level of the limb. The defeat of various vascular pools predetermines high mortality in acute decompensated arterial insufficiency and gangrene against vascular atherosclerosis. The highest mortality is characterized by amputation at the hip level (up to 40%), as well as in complex interventions including direct revascularization and necrectomy (up to 20%).
Loss of the supporting function of the leg leads to a permanent disability. According to statistics, after amputation at the shin level, only 30% of patients endure the limb, at the hip level - no more than 10%. Only 15% of patients use orthopedic footwear after amputations at the ankle level. The progression of the underlying disease and the unresolved problems of medical and social rehabilitation after amputation lead to the fact that in 2 years after the amputation of the thigh half of the patients die, and one third of the survivors lose the second limb. After amputation after 2 years, the mortality rate reaches 15%, 10% of the patients who are operated on the limb, 5% of the contralateral patients lose their limb, and 1% of the patients have both extremities.