开放骨折处理（英文）

Zdravotnické nakladatelství Galén © Česká společnost pro ortopedii a traumatologii 2006 Úvodní strana / Home Webmaster Provozovatel webu AKTUÁLNÍ ČÍSLO ARCHÍV PERIODIKUM REDAKČNÍ RADA POKYNY PRO AUTORY INSTRUCTIONS TO AUTHORS PŘEDPLATNÉ SUBSCRIPTION INZERCE Souborný referát / Current concepts review ACTA CHIRURGIAE ORTHOPAEDICAE ET TRAUMATOLOGIAE ČECHOSL., 73, 2006, p. 301 Open Fractures and Infection Otevřené zlomeniny a infekce Th. NEUBAUER1, G. S. BAYER2, M. WAGNER1 1 Department of Traumatology, Wi lhelminenspital der Stadt Wien, Austr ia 2 Department of Plast ic and Reconstruct ive Surgery, Wi lhelminenspital der Stadt Wien, Austr ia SUMMARY Open fractures still represent a major challenge for the treating surgeon and frequently demand a complex of soft tissue and bone procedures to achieve an undisturbed healing with adequate limb function. However, despite improvement in operative techniques and antibiotic therapy septic complications still occur in severe open fracture forms up to 50%. They are still deleterious for the patient as well as a major economic factor for the treating hospital. Radical (repetitive) debridement of the wound and coverage of soft tissue defects are of utmost importance in the prophylaxis of septic complications along with antibiotic therapy. If the local wound requires flap coverage, early performed procedures yield a clear decrease of infection rates even in most severe fracture forms. Osseous stabilization contributes to infection prophylaxis, especially when the implants can be inserted in a minimal invasive way and provide an adequate handling of soft tissues and the wound. Thus, most often intramedullary nails and external fixators are used today for osteosynthesis. Recently developed plates with angular stability offer a promising alternative even in open fractures, especially when there is an extension of the fracture into the meaphyseal area though indications have to be evaluated. Manifest septic complications demand an early and aggressive approach with radical eradication of the septic topic. While acute infections require most often only minor surgical procedures and offer the chance to leave implants in situ, chronic infections usually demand complex reconstructive measures of bones and soft tissues. Key words: open fractures, classification, soft tissue coverage, infection. INTRODUCTION Infection still represents one of the major complications in the treatment of open fractures though results have improved during the last century. Break down of the tissue barrier between the fracture zone and the environment leaves the underlying bone prone to direct contact with contaminating agents, mirrored in positive wound cultures up to 60 %-70 % (22, 57, 58). Figures from the 19th century demonstrate that in preceding centuries the major concern was the survival of the patient with primary mortality rates of about 50 % and another 40 % mortality in subsequent amputations (24, 42). Due to improved aseptic and operative techniques, survival rates of the patients increased. However, loss of the injured extremity due to wound infection and non-union was of major concern, especially when combined with a major vascular trauma (9). Though survival of the patient as well as salvage of the extremity can be achieved today in most patients, open fractures are still prone to complications. Ochsner (49) found in ORIF procedures an over-all infection rate of 6,2 % in open fractures compared to 1,9 % in closed fractures. Depending on the anatomic site and on the severity of soft-tissue trauma up to 50 % infectious complications have been reported (15, 22, 73) with the tibia being most often affected (53, 64). Thus, subsequent chronic osteitis and/or non-union still represent today a major source of disability and decreased quality of life for the individual patient as well as a socio-ecconomic problem for public health systems. CLASSIFICATION As the severity and amount of the soft tissue damage determine a complex treatment concept of surgical and conservative measures, classification of these fractures is of utmost importance. The classification system of Gustilo et al. was established in 1976 (22) and still included important parameters like the skin wound, amount of muscle damage and fracture type (Table 1), which allowed to draw therapeutic conclusions for an individual fracture. Gustilo et al. (23) modified the classification in 1984 by dividing fracture type III into subclasses A, B and C (Table 2) depending on the coverage of bone by soft tissues and vascular compromise, respectively. Though accused of high inter -observer errors due to subjective influence on injury description (4), Gustillo's system still represents a global classification system for open fractures. It's simplicity makes it prone for the use in clinical routine and it's subgroups allow prognostic conclusions in respect to possible complications, which increase with Gustillo's classification number (43, 45, 73). Muhr (47) reported in a survey of the literature the risk of acute infection in open fractures Gustillo's grade I with 0 %-2 %, in type II fractures of 5 % and in type III fractures of up to 10 %-25 %, respectively. Weiz- 页码，1/10(W)w 2011/6/7http://www.achot.cz/detail.php?stat=1 Marschall (73) found a similar distribution in the American literature with 0 % infection rate in type I, up to 12 % in type II and up to 50 % in type III fractures. Other classification systems like the classification system of Tscherne and Oestern (68) (Table 3) and the AO Müller Classification (63) (Table 4) provide more refined descriptions of the local situation, as lesions of bone, soft tissues and neurovascular structures and the grade of contamination are evaluated seperately. On the other hand their detailed classification of different parameters in an open fracture result in a descriptive complexity, which makes communication in daily routine more difficult than Gustillo's classification. In many fractures the whole amount of soft tissue damage can be comprehended yet a few days after the trauma, when demarcation of necroses is delayed (Fig. 1). Thus, independently on the system used, classification of an open fracture should be re-evaluated after the initial debridement (68). PATHOMECHANISM OF INFECTION Contamination and virulence Contamination of the wound is dependent on the kind of accident with rates of primary colonization being reported as high as 70 %-80 % (23, 37, 58, 59). Smears reveal most often Gram-positive Staph. aureus and epidermidis and in Gram-negative species Bacilli, Pseudomonas, Acinetobacter or Enterobacteriae (22, 40, 45, 51, 52, 61, 64). Though the microbiological pattern at the wound site may be influenced by environmental factors (agricultural injury, gun-shot injury, water injury?) which have to be considered in the antibiotic management (37, 66, 76) it is well known that most infections in open fractures are of nosocomial origin as causative micro-organisms of infection are different to those found in initial smears (40, 45). Kindsfater et al. (37) reported that 25 % of infections were caused by micro-organisms found in initial examinations and Lee (40) evaluated only 8 % of microorganisms on pre-debridement cultures to be the infectious agens. Thus, infection rates can be positively influenced by prophylactic, hygenic requirements. Rojcyk et al. (58) demonstrated that coverage of the wound with a sterile dressing at the accident site and it's removal under sterile conditions in the operating room can reduce the infection rate from 19,2 % to 4,3 % (Fig. 2). In contrast to their number the virulence of inoculated micro-organisms cannot be influenced in the stadium of the acute trauma. Only a long lasting and global change of treatment strategies with avoidance of uncritical and unexperienced use of antibiotics can provide a successful reduction of the selection and infection with problematic micro-organisms like multiresistant staphylococci (MRSA / MRSE, ORSA / ORSE). Local and general factors of defence Vascularity at the fracture site represents the most important factor in the local defence of inocculated micro-organisms. It's importance is mirrored in high rates of infectious complications (11, 64, 66) in Gustillo's IIIC fractures. Additionally, wound morphology at the fracture site contributes to the multiplication of microorganisms when caves, restricted fluids or hematomas provide an excellent local environment. From a biological point of view fracture stabilization with implants increases the local compromise to the soft tissues by adding a surgical trauma and inserting a foreign body (45). On the other hand, there is evidence that fracture stabilization decreases the rate of septic complications (25, 74). Thus, osteosynthesis techniques preserving the soft tissues by a minimal approach while providing a high amount of stability will contribute to the prophylaxis of infection. For diaphyseal fractures these techniques include the external fixator, the unreamed nail and minimal invasively inserted plates bridging the fracture zone. Systemic factors As most open fractures are caused by considerable trauma, the percentage of associated injuries in these patients is high and polytrauma not uncommon. Muhr (48) reported in a survey of the literature 30 页码，2/10(W)w 2011/6/7http://www.achot.cz/detail.php?stat=1 Fig. 1. Z. W., 39 years, motorcycle accident, male, sustained open tibial fracture Gustillo IIIc, with traumatic dissection of the posterior tibial artery: a) Osseous lesion represented an irregular 43-C.3 fracture with an associated segmental fibula fracture at three levels. b) Dorsomedial laceration of the skin with distinct subcutaneous degloving injury, local muscle destruction and disruption of the posterior tibial artery; (AO - class.: 43 C3, IO4, MT4, NV3). % polytrauma patients among open fractures and Schandelmeier et al. (60) found in a group of IIIB tibia fractures only 18 % isolated injuries. Therefore additional systemic compromise due to multiorgan failure or a suppressed immune system may influence the local situation in these patients. In elderly patients and low-energy trauma pre-existing vascular disease may add further compromise to the local situation, especially in certain anatomic areas - like the tibia - with preexisting critical vascularity. THERAPY OPTIONS Open fractures are emergencies and require prompt and adequate treatment including a complex of combined bone and soft tissue procedures. The aim of treatment in open fractures is the restoration of the limb's full function by an adequate healing of soft tissues and bone without infection (26, 66). By respecting the established therapeutic principles complications, especially infection rates, can be improved dramatically (Table 5). Local debridement and soft-t issue care The quality of the initial debridement represents the key -point in the treatment of open fractures and their infection prophylaxis (66). Radical removal of all devitalized tissues along with a copious irrigation of the wound are of paramount importance (22, 35, 48) as the nutritial basis for micro-organisms is removed and the number of inoculi can be reduced by 80 % (47). However, one has to consider that irrigation with high pressure pulsatile systems can add tissue damage and propagate foreign bodies or bacteria deeper into the wound (27). Debridement must include all bone areas of uncertain vascularity, which can decrease infection rates dramatically by 33 % (12). The time elapsing between injury and the start of operative wound debridement is considered as an important factor contributing to the prophylaxis of wound infections (11, 26, 31, 36, 37). Though not proofed by evidenced data, a positive influence on bone healing and wound infections can be observed when initial debridement is started within 6 hours from injury. In most severe soft tissue damage even primary amputation has to be considered, to avoid prolonged disability and a limb without function after many reconstruction attempts. Especially in polytrauma patients with a critical general state the rule "limb for life" still has it's values. Objective and absolute criterias for primary amputation in open tibia fractures were defined by Lange et al. (39) as a prolonged ischemia of more than 6 hours in IIIC fractures and a complete destruction of the posterior tibial nerve with loss of protective sensation in adults. Discrimination between a salvagable or non-salvagable extremities may be supported by the MESS-score (28). It represents a relative easily assessable scoring system, where values of >7 pts. being absolute predictable for amputation (Table 6). Antibiotic treatment Systemic administration of antibiotics represented one key-point in Gustilo's treatment concept (22) and it has been proofed that the infection rate in open fractures can be reduced by it. Patzakis et al. (51) demonstrated in a prospective, randomized trial of 333 open fractures that infection rates decreased to 2,3 % by the administration of cephalothin compared to 13,9 % infections in the group without antibiotic treatment. The selection of antibiotics should be based on the microbiological findings and must especially cover nosocomial pathogens like Staphylococcus aureus, Gram negative bacilli or Pseudomonas aeruginosa (22, 51, 57, 66, 74). A widely used combination, covering Gram positive as well as Gram negative microorganisms, includes a first generation cephalosporine and aminoglycosides (45, 76); it can be adapted to special injury patterns and environmental situations like farmyard accidents, water injury or wounds with fecal contamination (66). Antibiotic treatment should be started as soon as possible after the injury and maintained long enough to destroy all micro-organisms. On the other hand development of resistant pathogens and secondary infections under a prolonged therapy have to be avoided. Therefore, it seems reasonable to limit antibiotic treatment for three days with repeated three days administrations for major surgical procedures and for wound closure (52, 66, 76). Local antibiotic carriers Local antibiotic carriers provide high tissue levels of the drugs and almost no systemic toxicity, which is especially useful in severe soft-tissue damage and gross contamination and/or impaired vascularity. Most often gentamycin augmented beads are used to support the antimicrobic activity of parenteral administered antibiotics (46, 50). Ostermann et al. (50) observed a decrease of the over all infection rate of open fractures from 12 % down to 3,7 % when an antibiotic therapy with tobramycin,l cefazolin and penicillin was supplemented by local antibiotic beads. This differences seem to be especially significant in severe fracture forms (62). Antibiotic beads can fill contaminated primary or secondary bone defects till they can be definitively operated on. Facture stabil ization Most open fractures - especially of higher grade (GII/GIII) - are unstable and require surgical fixation. Apart from facilitated nursing and early mobilization of the patient the mechanic stability achieved by 页码，3/10(W)w 2011/6/7http://www.achot.cz/detail.php?stat=1 c) After emergency debridement and surgery of the soft tissues the resulting skin defects were left open and covered temporarily with Epigard?. The tibia was fixed with a LCP-distal tibia plate inserted via minimal invasive approach while the segmental fibula fracture was stabilised with ESIN rod. d) End - end anastomosis of the posterior tibial artery at emergency surgery. e) Follow-up debridements resulted in distinct skin and soft tissue defects dorsomedially, though arterial repair was still covered by vital tissues. f) Proximal defect was covered by a gastrocnemius flap and healed uneventful. Distal defect was covered by a free vascularized gracilis flap, which was lost due to venous thrombosis. Revision surgery after flap removal and covarage with microvascular latissimus dorsi flap osteosynthesis contributes to the prophylaxis of bone / soft-tissue infections (74). The choice of implant must be adapted to the "personality of the fracture", especially the anatomic site, the amount of soft tissue damage and the degree of contamination. Implant selection in the acute situation sometimes has to find a compromise between an optimal biomechanic solution and a possible implant-interference with local wound management. So external fixators, intramedullary nails (IMN) and percutaneously inserted plates are viable options in open fractures. However, definitive stabilization must not be achieved initially at all costs as temporary administration of an external fixator with conversion to internal fixation after soft tissues recovery represents a reasonable treatment concept (2). External f ixator (E. F.) Application of an E. F. is usually quickly achieved with no implant material submerged beneath the skin. Thus, heavily contaminated fractures, extensive soft tissue damage or selected situations of polytraumatized patients are prone to the treatment with external fixators as the fixator pins usually do not interfere with local wound care. However, the pin positions have to be considered when a flap coverage is planned, to avoid irridation of the flap design. Furthermore, external fixation alone till osseous union is affected by complications at the pin sites, malunion, refractures, deep infection and non-union. Septic complications often originate from pintrack infections (12, 21, 29) when conversion to intramedullary stabilization is delayed (15) where infection rates of nearly 50 % are reported (44). On the other hand Blachut et al. (2) yielded excellent functional results with only 5 % septic complications, when conversion to IMN was performed as early as two weeks after injury. Schandelmayer et al. (60) reported in Gustilo IIIb fractures of the tibia the functional impairment due to a reduced mobility of the ankle joint and toes clearly increased in the group of external fixator compared to IMN. Intramedullary nails Nailing as the golden standard for the treatment of shaft fractures can be also used in open fractures of type I-III (2, 3, 38, 67). Krettek et al. (38) evaluated in a meta- analysis of open tibia fractures with 341 UTN stabilizations an over-all infection rate of 4 %-9 %, with 7 %-24 % infections in grade G III fractures. In comparison to external fixation no significant difference can be found in the time required for bone healing and in the rate of deep infection (Table 7). However, Bhandari et al. (1) reported in a survey of randomised studies with 396 patients and open tibia fractures a significant lower incidence of reoperations, superficial infections and malunions when the treatment consisted of unreamed nails. 页码，4/10(W)w 2011/6/7http://www.achot.cz/detail.php?stat=1 showed successful healing without infection. Soft tissue situation 6 months after coverage. g) Radiographs 18 months after trauma reveal osseous bridging of the fracture zone on the lateral side, though medial bridging is uncertain. h) 18 months after trauma patient works in preinjury occupation and shows unlimited range in knee and ankle joint, though some pains are reported in the lower leg after long distance walking (a, b). Though experimental evidence exists, that unreamed nailing results in less endosteal vascular compromise than reamed procedures, prospective randomized studies comparing both nailing techniques did not show a significant difference in infection rates (14, 3