Intramedullary pressure and bone marrow fat extravasation in reamed and unreamed femoral nailing

Intramedullary nailing for floating knee injury complicated by pulmonary fat embolism: A case report and literature review

A 28-year-old man involved in a serious motorcycle accident was admitted to our hospital with comminuted fractures of the ipsilateral femoral shaft and tibial shaft, as well as multiple fractures of the right lower limb, including the proximal fibula, medial malleolus, and the third and fourth distal metatarsals. In addition, the patient suffered a skin contusion and laceration of the right foot. On the first day of admission, this patient suddenly developed tachycardia, pyrexia, and tachypnoea, and was immediately transferred to the ICU for further treatment due to a CT-diagnosed pulmonary fat embolism (FE). As a symptomatic treatment, he received a prophylactic dose of low-molecular-weight heparin for 10 days, after which his condition improved. A Doppler ultrasound of the lower leg and a follow-up chest CT angiography were performed, which excluded any remaining thrombus and verified that the pulmonary FE had improved without deterioration. Closed-reduction and retrograde intramedullary nailing were performed for the femoral shaft fractures, while antegrade intramedullary nailing was performed for the tibial shaft fractures under general anaesthesia. In the three-year follow-up, the patient had recovered with good function of the right limb, without any respiratory discomfort. Both the femoral and tibial shaft fractures finally resolved without any further treatment. Ipsilateral femoral and tibial shaft fractures should undergo surgical stabilisation as early as possible to avoid pulmonary FEs. It is still controversial whether intramedullary nailing is suitable for floating knee injuries complicated by pulmonary FEs. However, if patients with pulmonary FEs require intramedullary nailing, we suggest that surgery should be performed after at least one week of anticoagulant use, when patient vital signs are stable and there is no sign of dyspnoea. In addition, patients should try to avoid reaming during the operation to prevent and decrease "second hit" for the lung.

In vivo study to assess fat embolism resulting from the Reamer-Irrigator-Aspirator 2 system compared to a novel aspirator-based concept for intramedullary bone graft harvesting

INTRODUCTION

Fat embolism (FE) following intramedullary (IM) reaming can cause severe pulmonary complications and sudden death. Recently, a new harvesting concept was introduced in which a novel aspirator is used first for bone marrow (BM) aspiration and then for subsequent aspiration of morselized endosteal bone during sequential reaming (A + R + A). In contrast to the established Reamer-Irrigator-Aspirator (RIA) 2 system, the new A + R + A concept allows for the evacuation of fatty BM prior to reaming. In this study, we hypothesized that the risk of FE, associated coagulopathic reactions and pulmonary FE would be comparable between the RIA 2 system and the A + R + A concept.

MATERIALS AND METHODS

Intramedullary bone graft was harvested from intact femora of 16 Merino sheep (age: 1-2 years) with either the RIA 2 system (n = 8) or the A + R + A concept (n = 8). Fat intravasation was monitored with the Gurd test, coagulopathic response with D-dimer blood level concentration and pulmonary FE with histological evaluation of the lungs.

RESULTS

The total number and average size of intravasated fat particles was similar between groups (p = 0.13 and p = 0.98, respectively). D-dimer concentration did not significantly increase within 4 h after completion of surgery (RIA 2: p = 0.82; A + R + A: p = 0.23), with an interaction effect similar between groups (p = 0.65). The average lung area covered with fat globules was similar between groups (p = 0.17).

CONCLUSIONS

The use of the RIA 2 system and the novel A + R + A harvesting concept which consists of BM evacuation followed by sequential IM reaming and aspiration of endosteal bone, resulted in only minor fat intravasation, coagulopathic reactions and pulmonary FE, with no significant differences between the groups. Our results, therefore, suggest that both the RIA 2 system and the new A + R + A concept are comparable technologies in terms of FE-related complications.

Reaming the intramedullary canal during tibial nailing does not affect in vivo intramuscular pH of the anterior tibialis

Many investigations have evaluated local and systemic consequences of intramedullary (IM) reaming and suggest that reaming may cause, or exacerbate, injury to the soft tissues adjacent to fractures. To date, no study has examined the effect on local muscular physiology as measured by intramuscular pH (IpH). Here, we observe in vivo IpH during IM reaming for tibia fractures.

Methods

Adults with acute tibia shaft fractures (level 1, academic, 2019-2021) were offered enrollment in an observational cohort. During IM nailing, a sterile, validated IpH probe was placed into the anterior tibialis (<5 cm from fracture, continuous sampling, independent research team). IpH before, during, and after reaming was averaged and compared through repeated measures ANOVA. As the appropriate period to analyze IpH during reaming is unknown, the analysis was repeated over periods of 0.5, 1, 2, 5, 10, and 15 minutes prereaming and postreaming time intervals.

Results

Sixteen subjects with tibia shaft fractures were observed during nailing. Average time from injury to surgery was 35.0 hours (SD, 31.8). Starting and ending perioperative IpH was acidic, averaging 6.64 (SD, 0.21) and 6.74 (SD, 0.17), respectively. Average reaming time lasted 15 minutes. Average IpH during reaming was 6.73 (SD, 0.15). There was no difference in IpH between prereaming, intrareaming, and postreaming periods. IpH did not differ regardless of analysis over short or long time domains compared with the duration of reaming.

Conclusions

Reaming does not affect IpH. Both granular and broad time domains were tested, revealing no observable local impact.

Distribution of coolant during drilling with open type internally cooled medical steel drill

INTRODUCTION

Internally cooled bone drills with an open system, conduct coolant directly to the point of contact of cutting surface of the drill and the bone and lower the temperature at the drilling site. During bone drilling with internally cooled drills of open type, there is a possibility that coolant enters the intramedullary canal and has an adverse effect on intramedullary pressure. In this research, the intramedullary distribution of the coolant during and after drilling was analyzed.

MATERIALS AND METHODS

Specially constructed open type internally cooled medical steel drills were used. Experimental studies were conducted on the porcine femoral bone diaphysis. Coolant (saline) was mixed with water-soluble contrast agent and x-ray images of the distribution of coolant during and after drilling were taken with different regimes of drilling (drill rotational speed from 1300 rpm to 5000 rpm, and coolant flow rate from 0,6 l/min to 1,35 l/min).

RESULTS

An x-ray images showed that coolant did not spread from the borehole and has not spread intramedullary with any combination of coolant flow and drill rotation regimes.

CONCLUSION

Coolant does not disperse into the intramedullary canal outside of the borehole in given flow ranges (0,6-1,35 l/min) and drill rotational speed regimes (1300-5000 rpm). Open type internally cooled can safely be used for bone drilling.

Guidelines for the acute care of severe limb trauma patients

GOAL

To provide healthcare professionals with comprehensive multidisciplinary expert recommendations for the acute care of severe limb trauma patients, both during the prehospital phase and after admission to a Trauma Centre.

DESIGN

A consensus committee of 21 experts was formed. A formal conflict-of-interest (COI) policy was developed at the onset of the process and enforced throughout. The entire guidelines process was conducted independently of any industrial funding (i.e., pharmaceutical, medical devices). The authors were advised to follow the rules of the Grading of Recommendations Assessment, Development and Evaluation (GRADE®) system to guide assessment of the quality of evidence. The potential drawbacks of making strong recommendations in the presence of low-quality evidence were emphasised. Few recommendations remained non-graded.

METHODS

The committee addressed eleven questions relevant to the patient suffering severe limb trauma: 1) What are the key findings derived from medical history and clinical examination which lead to the patient's prompt referral to a Level 1 or Level 2 Trauma Centre? 2) What are the medical devices that must be implemented in the prehospital setting to reduce blood loss? 3) Which are the clinical findings prompting the performance of injected X-ray examinations? 4) What are the ideal timing and modalities for performing fracture fixation? 5) What are the clinical and operative findings which steer the surgical approach in case of vascular compromise and/or major musculoskeletal attrition? 6) How to best prevent infection? 7) How to best prevent thromboembolic complications? 8) What is the best strategy to precociously detect and treat limb compartment syndrome? 9) How to best and precociously detect post-traumatic rhabdomyolysis and prevent rhabdomyolysis-induced acute kidney injury? 10) What is the best strategy to reduce the incidence of fat emboli syndrome and post-traumatic systemic inflammatory response? 11) What is the best therapeutic strategy to treat acute trauma-induced pain? Every question was formulated in a PICO (Patient Intervention Comparison Outcome) format and the evidence profiles were produced. The literature review and recommendations were made according to the GRADE® methodology.

RESULTS

The experts' synthesis work and the application of the GRADE method resulted in 19 recommendations. Among the formalised recommendations, 4 had a high level of evidence (GRADE 1+/-) and 12 had a low level of evidence (GRADE 2+/-). For 3 recommendations, the GRADE method could not be applied, resulting in an expert advice. After two rounds of scoring and one amendment, strong agreement was reached on all the recommendations.

CONCLUSIONS

There was significant agreement among experts on strong recommendations to improve practices for severe limb trauma patients.

Does Intramedullary Nail Fixation of the Tibia Pose the Same Risk of Pulmonary Complications as Intramedullary Nail Fixation of the Femur? A Propensity Score-Matched Analysis

OBJECTIVES

To compare duration of mechanical ventilation and pulmonary outcomes in patients treated with intramedullary nail (IMN) fixation of the tibia versus the femur.

DESIGN

Retrospective cohort study.

SETTING

Level I trauma center.

PATIENTS

One thousand thirty patients were categorized based on treatment: those treated with IMN of the tibia (n = 515) and those treated with IMN of the femur (n = 515).

INTERVENTION

IMN fixation of tibial and femoral fractures.

OUTCOME MEASUREMENTS

The primary outcome was duration of mechanical ventilation. Secondary outcomes included length of intensive care unit (ICU) stay and risk of tracheostomy, pulmonary embolism (PE), acute respiratory distress syndrome (ARDS), and mortality.

RESULTS

In an unadjusted analysis, femoral fractures were associated with increase in ventilator days (mean difference, 1.4; P < 0.001), ICU days (mean difference, 1.8; P < 0.001), and odds of tracheostomy (odds ratio, 1.7; P < 0.01). No difference was shown in likelihood of PE, ARDS, or mortality (P > 0.2). Propensity score-matched estimates showed no differences in any measured outcomes (P > 0.40). In patients with Injury Severity Scores >17, we found no difference in length of ventilator or ICU days or likelihood of tracheostomy, PE, ARDS, or mortality in the unadjusted (P > 0.2) or propensity score-matched estimates (P > 0.3).

CONCLUSIONS

These findings suggest that IMN fixation of the tibia is associated with duration of mechanical ventilation and risk of poor pulmonary outcomes similar to those of femoral nailing, after adjustment for baseline characteristics.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Impact-driven, pulmonary emboli of osseous fat in exercise-induced bronchospasm

Exercise induced bronchospasm (EIB) affects approximately 10% of normal individuals with higher prevalence rates among children, obese adults, and competitive athletes. Although hyperpnea with dry air is the best known cause, the problem is multifactorial with atopy, asthma and chlorine all playing established roles. To date, no clear mechanism has connected musculoskeletal loading with the ensuing pulmonary compromise. This paper reviews evidence that impact-driven pulses in subchondral bone pressure may push osseous fat cells into the local venous sinusoids. The resultant showers of microemboli must then travel to the lung where lysis of membrane phospholipids leads to leukotriene formation with resultant inflammation and bronchial hypersensitivity. Concurrently, the same emboli deliver triglyceride fuels for further physical activity. Thus, pulmonary microemboli derived from osseous fat may resolve the seeming paradox of athletic excellence in persons afflicted with exercise-induced bronchospasm.

The effect of patient position during trauma surgery on fat embolism syndrome: An experimental study

BACKGROUND

The aim of this study was to compare the effect of supine versus lateral position on clinical signs of fat embolism during orthopedic trauma surgery. Dogs served as the current study model, which could be extended and/or serve as a basis for future in vivo studies on humans. It was hypothesized that there would be an effect of position on clinical signs of fat embolism syndrome in a dog model.

MATERIALS AND METHODS

12 dogs were assigned to supine (n = 6) and lateral (n = 6) position groups. Airway pressures, heart rate, blood pressure, cardiac output, pulmonary artery pressure, pulmonary artery wedge pressure, right atrial pressure, arterial and venous blood gases, white blood count, platelet count and neutrophil count were obtained. Dogs were then subjected to pulmonary contusion in three areas of one lung. Fat embolism was generated by reaming one femur and tibia, followed by pressurization of the canal.

RESULTS

No difference was found in any parameters measured between supine and lateral positions at any time (0.126 < P < 0.856).

CONCLUSIONS

The position of trauma patients undergoing reamed intramedullary nailing did not alter the presentation of the features of the lung secondary to fat embolism.

Cytokine productive capacity of alveolar macrophages and Kupffer cells after femoral fracture and blunt chest trauma in a murine trauma model

INTRODUCTION

Specific cellular and inflammatory factors that contribute to the severity of pulmonary dysfunction after blunt chest trauma and osteosynthesis of femoral fractures are yet not fully understood. Therefore, we investigated alterations of the cytokine productive capacity of alveolar macrophages (AM) and Kupffer cells (KC) after femoral fracture stabilized with intramedullary pin with or without blunt chest trauma.

MATERIALS AND METHODS

In male C57BL/6N mice an intramedullary pin was implanted in an intact femur as the sham procedure. In trauma groups mice either received an isolated femoral fracture with subsequent fracture stabilization with an intramedullary pin (group Fx) or a combined trauma of blunt chest trauma and femur fracture also stabilized by an intramedullary pin (group TTFx). Animals were sacrificed 0h, 6h, 12h, 24h and 3d after trauma induction. Cytokine concentrations were measured in plasma and supernatant of cultivated AM and KC by FACS analysis. Pulmonary and hepatic infiltration of polymorphonuclear leukocytes (PMN) was determined by Ly6G-staining.

RESULTS

At 6h, isolated femoral fracture with intramedullary stabilization resulted in a significantly increased productive capacity of KC (IL-6, TNF-α, CCL2, CCL3, CCL5 and CCL7) compared to sham animals. Combined trauma additionally resulted in an increased productive capacity of AM (IL-6, TNF-α, CCL2, CCL3, CCL4, CCL5 and CCL7) at 6h and the effect was prolonged up to 3d compared to controls. Combined trauma also led to a significant higher amount of plasma CCL2 at 3d and plasma CCL7 at 6h after the insult compared to group Fx. Compared to shams, pulmonary and hepatic infiltrations of PMNs were increased in group Fx and TTFx after 6h, but in the combined trauma model the effect was prolonged up to 3d.

CONCLUSION

An intramedullary stabilized femur fracture alone results in a significant activation of the immune response. The combination of femoral fracture and blunt chest trauma however, results in an increased and prolonged activation of the inflammatory response. Transferred to the clinical setting, these results emphasize the critical role of severe chest trauma for treatment strategies of femoral fractures in multiple trauma patients.

Expandable intramedullary nails in lower limb trauma: a systematic review of clinical and radiological outcomes

This study systematically reviews the evidence-base for the use of expandable nails in the treatment of acute diaphyseal fractures of the lower limb. Both electronic and hand searches were undertaken of the published and grey literature to 1 December 2011. A total of 154 citations were identified, of which 15 were deemed suitable and assessed with the Critical Appraisals Skills Programme tool. A total of 625 nailing procedures were performed in 620 patients: 279 femoral and 346 tibial nails. The expandable nail was found to be significantly quicker to insert than interlocked nails (p < 0.05), and the total incidence of non-union or other complication was 13 and 14 % for expandable femoral and tibial nails, respectively. Notable complications with the expandable nail included fracture propagation on nail inflation in 2.5 % and post-operative shortening in 3.3 %. Device failure secondary to problems with the expansion mechanism was seen in 2.9 %. The rate of non-union and infection following expandable nailing was 3.1 and 1.4 %, respectively. Despite promising initial results, there remains a paucity of good quality studies to support the use of expandable nails over interlocked nails for the treatment of acute diaphyseal fractures of the lower limb.

The physiologic and pathologic effects of the reamer irrigator aspirator on fat embolism outcome: an animal study

OBJECTIVES

Intramedullary reaming of long bones before nail insertion has been known to cause an increase in fat emboli introduction into the bloodstream, which is a potentially fatal phenomenon. The goal of this study was to assess whether the reamer irrigator aspirator (RIA) reamer can reduce fat embolic load compared with the standard AO reamer.

METHODS

Fifteen pigs were prepared using an intravenous catheter inserted into the marginal ear vein for fluid balance and drug administration. One third of the pig's blood volume was withdrawn to simulate hemorrhagic shock. Each animal underwent bilateral retrograde femoral reaming, cementing, and nailing using either an RIA or AO reamer. Assignment of a reamer type to the left or right side was done randomly and allowed for direct comparison of matching femur results. Outcome measures were obtained, namely, pulmonary arterial pressure, mean arterial pressure, partial pressure of arterial oxygen, and cardiac output. Staining techniques were used to ascertain fat emboli counts from lung tissue samples.

RESULTS

For mean arterial pressure, partial pressure of arterial oxygen, and cardiac output after cement injection, the RIA reamer group showed statistically higher values than the AO reamer group. In corollary, the RIA showed statistically lower pulmonary arterial pressure levels. No differences were noted at baseline, during hypovolemia, and post resuscitation. With the Student t test, no statistical differences were found between reamers regarding fat emboli counts for both staining methods. With the Mann-Whitney test, the RIA reamer showed statistically fewer emboli (7.0 versus 74.5) (P = 0.02, Z = 2.33) using Oil Red "O" staining.

CONCLUSIONS

The RIA reamer demonstrated superior results with respect to physiologic measures and fat emboli counts and may provide optimal results compared with the AO reamer.

Fracture healing after reamed and unreamed intramedullary nailing in sheep tibia

Intramedullary nailing is a well-established method for stabilisation of long-bone shaft fractures. It is still a controversy as to whether the procedure should be done by an unreamed or reamed technique. In the present animal study, 24 sheep were treated with intramedullary nailing. Midshaft fractures (Arbeitsgemeinschaft für Osteosynthese (AO) type 42-A2/3) were created. Eight sheep were treated with an unreamed nailing technique (UN), a further eight sheep underwent tibia nailing by the reamed technique using the conventional AO reaming system (RC) and in a further eight sheep, reamed nailing was performed using an experimental reaming system (RE). Intra-operatively, the intramedullary pressure was measured and, during a healing time of 10 weeks, the growth of callus formation was labelled with fluorescence markers after 4 and 6 weeks. After 10 weeks, the animals were euthanised and the quality of fracture healing was determined by recording stiffness in torsion, antero-posterior and mediolateral bending and the load at yield. In addition, the callus formation at the fracture zone was evaluated by fluorescence microscopy and macroradiographs. The results showed a decrease of intramedullary pressure when reamed nailing was performed with the RE (72.5 mmHg) system compared with the conventional AO reaming system (227 mmHg). Mechanical testing did not reveal any significant differences either for torsional or bending stiffness or for load at yield for any of the three procedures. Histological evaluation showed a similar callus formation for the UN group and the RE group. Callus formation in the UN (65 mm(2)) and RE (63 mm(2)) groups showed a higher increase during the first 6 weeks than those treated with the conventional AO reaming system (27 mm(2)). This means that, especially during the first weeks of fracture healing, damage to the bone by the reaming process can be reduced by reaming with a reaming device with lowered cutting flutes and smaller drive-shaft diameter. Intramedullary pressure can be significantly reduced by using reaming systems with reduced drive-shaft diameters and deepened cutting flutes. In the early phase of fracture healing, callus formation can be influenced positively when using the RE system.

Reaming as an adjuvant to irrigation on bacterial presence and propagation: an open, cadaveric intramedullary fracture model

OBJECTIVES

The purpose of this investigation is to evaluate the effect of intramedullary reaming on bacterial presence and propagation in an open, cadaveric intramedullary fracture model.

METHODS

Twelve fresh-frozen human cadaveric femurs were osteotomized and inoculated with Staphylococcus aureus, the open, cadaveric intramedullary fracture model. Low-pressure pulsed lavage irrigation was performed to irrigate the osteotomy sites. The specimens were divided into two groups of six paired specimens: CNT, irrigation only; and REAM, irrigation coupled with intramedullary reaming. Intramedullary contents were cultured at the osteotomy site and in 1-cm increments through the distal femoral metaphysis. Mean bacterial colony-forming units were compared between groups using analysis of variance.

RESULTS

A statistically significant higher bacterial colony-forming unit count was noted at the osteotomy site (bacterial presence) in the CNT group compared with the REAM group. In terms of bacterial propagation, when compared with the sterile osteotomy site, the CNT group demonstrated significant bacterial propagation only at the 1.1- to 2.0-cm increment and the REAM group demonstrated no significant propagation. In comparing bacterial propagation between the CNT and the REAM groups, no significant differences were noted at any distal increment.

CONCLUSION

In this open, cadaveric intramedullary fracture model, low-pressure pulse lavage coupled with intramedullary reaming demonstrated significantly less bacterial presence at the osteotomy site compared with irrigation without reaming. Additionally, intramedullary reaming does not appear to significantly propagate bacteria into the intramedullary canal nor into the distal metaphysis. These observations might have clinical significance.

Pulmonary fat embolism after reamed and unreamed nailing of femoral fractures

BACKGROUND

To determine whether reamed or unreamed intramedullary nailing of femoral fractures results in higher incidence of pulmonary fat embolism, three different methods of intramedullary nailing were compared in sheep. To analyze the presence of bone marrow fat embolism in pulmonary arteries, histological evaluation was undertaken using a quantitative computer-assisted measurement system.

METHODS

In this experimental model of 27 female Swiss alpine sheep, an osteotomy of the proximal femur was conducted in each animal. Then, the animals were divided into three groups according to the method of treatment: two different reamed intramedullary nailing techniques and an unreamed nailing technique were used. In the first group "ER" (experimental reamer; n=9), the nail was inserted after reaming with an experimental reamer; in the second group "CR" (conventional reamer; n=7), the intramedullary nail was inserted after reaming with the conventional AO-reamer. In the third group "UN" (unreamed; n=8) unreamed nailing was performed. During the operation procedure intramedullary pressure was measured in the distal fragment. After sacrificing the animals, quantitative histological analyses of bone marrow fat embolism in pulmonary arteries were done using osmium tetroxide fixation and staining of the fat.

RESULTS

The measurement of intramedullary pressure showed significantly lower values for reamed nailing than for the unreamed technique. The quantitative histological evaluation of lung vessels concerning bone marrow fat embolism revealed a statistically significant difference between reamed and unreamed insertion of the nail: 7.77%±6.93 (ER) and 6.66%±5.61 (CR) vs. 16.25%±10.05 (UN) (p<0.05) of the assessed lung vessels were filled with fat emboli. However, no difference was found between the traditional and experimental reamer.

CONCLUSIONS

Intramedullary nailing after reaming is a safe procedure with low systemic embolisation when compared to the unreamed insertion of the nail.

The biology of intramedullary reaming

In this review we focus on the local biologic and physiologic effects of intramedullary reaming of long bones. Among the topics discussed are the consequences for vascularity, as well as the pathophysiology of intramedullary pressure generation and temperature increase. Reaming techniques and their suggested effects on bone formation are outlined. Moreover, techniques for avoiding local and systemic complications are summarized.

[Unreamed intramedullary nailing]

Reaming and non-reaming of intramedullary nails in long bone fractures was a controversial and even emotional topic in recent decades. This article gives an historical overview of the development in this field and presents the background to the need for unreamed nailing. Furthermore, the current state of knowledge is illustrated by describing the results of a series of randomised controlled trials. Before the year 2000 nearly all German handbooks on orthopaedic and trauma surgery recommended unreamed intramedullary nailing as a more "biological" treatment that causes less harm to vascularity with equal or even better results. Unreamed nailing was in particular advocated for the treatment of open fractures. The tide turned as randomised controlled trials conducted since 2000 gave evidence that unreamed nailing leads to a higher rate of delayed or non-union, while the advantages to blood supply and infection rate could not be proven. According to evidence based medicine isolated femur and tibia fractures should be nailed in a reamed procedure. In a severe multiple injury setting it is safer to stabilize long bone fractures with external fixators, as adverse events are described for reamed and unreamed nailing.

Post-operative Fat Embolism Syndrome: A case report and review of literature

Fat embolism occurs in all patients with long bone fractures and intra-medullary reaming of long bone but is usually asymptomatic. A few patients will have pulmonary, cerebral and dermal dysfunction; this triad is called fat embolism syndrome (FES). We report a case of FES developed after intramedullary nailing of both femurs that was successfully managed in our surgical intensive care unit (SICU).

Reaming does not add significant time to intramedullary nailing of diaphyseal fractures of the tibia and femur

BACKGROUND

Reamed intramedullary nailing is the current gold standard for the treatment of diaphyseal fractures of the femur and tibia. Current concepts of orthopedic damage control surgery for patients with multiple injuries have placed an emphasis on appropriate surgical timing, limiting blood loss, and the duration of the initial operative procedure(s). Proponents of unreamed nailing have stated that reaming places polytraumatized patients "at risk," in part because it adds to the length of the surgical procedure and may exacerbate the severity of a patient's pulmonary injury. The purpose of this study was to determine how many minutes reaming actually takes and what percentage of operative time reaming comprises during intramedullary nailing of femoral and tibial shaft fractures.

METHODS

Intraoperative timing data were collected prospectively on a total of 52 patients with 54 fractures (21 femoral and 33 tibial) who underwent reamed intramedullary nailing of acute closed or open femoral or tibial shaft fractures over a 10-month period. Total operating room, surgical, and reaming times were collected.

RESULTS

The average reaming time for femur and tibia fractures was 6.9 minutes and 7 minutes, respectively. On average, reaming accounted for 4.9% of the surgical time and 3.2% of the total operating room time for femur fractures and 4.9% of the surgical time and 3.4% of the total operating room for tibia fractures.

CONCLUSION

Our results show that reaming comprises a small percentage of the operative time and the total time a patient spends in the operating room.

Bilateral femoral fractures: does intramedullary nailing increase systemic complications and mortality rates?

In order to evaluate the impact of simultaneous intramedullary nailing in patients with bilateral femoral fractures on systemic complications a comprehensive review of the literature was performed. Four studies reporting the results of 197 patients following trauma were analysed. The mean Injury Severity Score was 20.6 (range, 9-75). According to the data available, reamed intramedullary nailing was performed in 96% of the cases. The incidence of fat embolism was 4.1%, ARDS 14.6% and pulmonary embolism 6.9%. The overall mortality was 6%. The mean hospital stay was 17.9 days (range, 4-108). Bilateral femoral fractures have a high risk of complications and mortality. Damage control surgery should be considered in these cases where the clinician anticipates the development of systemic complications.

Fat embolism

Fat embolism refers to the presence of fat droplets within the peripheral and lung microcirculation with or without clinical sequelae. The pathologic consequences of fat embolism are well recognized. Fat embolism is most often associated with trauma and orthopedic injuries. Fat embolism syndrome (FES) is a serious manifestation of fat embolism that involves a cascade of clinical signs such as petechial rash, deteriorating mental status, and progressive respiratory insufficiency, usually occurring within 24 hours of injury. This article reviews the definition, epidemiology, etiology, pathophysiology, clinical presentation, diagnosis, management, and prognosis of FES.

Fat extravasation due to unreamed and experimentally reamed intramedullary nailing of the sheep femur

AIM

To compare systemic fat extravasation in unreamed and experimentally reamed nailing.

METHODS

An osteotomy was created in the proximal third of the femoral shaft in 16 sheep, and intramedullary pressure increase and fat extravasation were monitored for the two nailing techniques.

RESULTS

The highest intramedullary pressures, median 2700 mm Hg, and highest percentages of fat extravasation, peaking at almost 90% of fat, were found for the unreamed nailing technique. The values for the reamed group were significantly lower.

CONCLUSIONS

The extravasation of intramedullary fat can be attributed to the great increase in intramedullary pressure that occurs during unreamed nailing. Correctly performed intramedullary reaming with the new reaming system produces lower pressures and much less systemic fat extravasation, reducing the risk for fat embolism.

Intramedullary nailing of femoral shaft fractures: current concepts

Intramedullary nailing is the preferred method for treating fractures of the femoral shaft. The piriformis fossa and greater trochanter are viable starting points for antegrade nailing. Alternatively, retrograde nailing may be performed. Each option has relative advantages, disadvantages, and indications. Patient positioning can affect the relative ease of intramedullary nailing and the incidence of malalignment. The timing of femoral intramedullary nailing as well as the use of reaming must be tailored to each patient to avoid systemic complications. Associated comorbidities, the body habitus, and associated injuries should be considered when determining the starting point, optimal patient positioning for nailing, whether to use reduction aids as well as which to use, and any modifications of standard technique. Intramedullary nailing of diaphyseal femur fractures provides a stable fixation construct that can be applied using indirect reduction techniques. This method yields high union rates and low complication rates when vigilance is maintained during preoperative planning, the surgical procedure, and the postoperative period.

Intramedullary nailing of the femur: current concepts concerning reaming

Intramedullary fixation has advanced to the standard of care for fractures of the femoral shaft. Current controversies center on whether to prepare the intramedullary canal by reaming, particularly in certain subsets of patients. As understanding of the local and systemic effects of reaming deepens, there is a role for maximizing the benefits of intramedullary preparation before nail fixation, while attempting to minimize the major disadvantages of this technique. Several treatment strategies have emerged to address the downsides of intramedullary reaming. The purpose of this review is to discuss the history and current knowledge of intramedullary reaming with respect to problems associated with its use and the evolution of treatment modalities and their clinical applicability for orthopaedic trauma care.

The stress response to bilateral femoral fractures: a comparison of primary intramedullary nailing and external fixation

OBJECTIVES

Concern has recently been expressed with regard to the physiologic effects of primary intramedullary femoral nailing in seriously injured patients. "Damage control orthopaedics" techniques have been proposed, which comprise principally the use of primary external fixation. The aim of this study was to compare the physiologic effects of external femoral fixation with those of intramedullary stabilization over the first 24 hours after femoral fracture using an established large animal (ovine) trauma model.

METHODS

Under terminal anesthesia, bilateral high-energy femoral fractures and hypovolemic shock were produced using a pneumatic actuator. Twenty-four sheep were randomized into 4 groups and monitored for 24 hours. Group 1--control, group 2--trauma only, group 3--trauma and external fixation, and group 4--trauma and reamed intramedullary nailing. Outcome measures included the following: pulmonary embolic load (transesophageal echocardiography), metabolic base excess, plasma coagulation markers, and polymorphonuclear cell counts obtained from bronchoalveolar lavage samples.

RESULTS

The total embolic load was significantly higher (P < 0.001) in the intramedullary nailing group. All trauma groups had a significant increase (P < 0.05) in prothrombin times with a fall in antithrombin III and fibrinogen levels. However, the type of fracture stabilization used did not significantly affect any of the other outcome measurements.

CONCLUSIONS

A higher pulmonary embolic load can be expected during early intramedullary femoral fracture stabilization compared with primary external fixation. However, the degree of stimulation to systemic coagulation and pulmonary inflammation by each type of surgery was comparable.

Emergency management of fat embolism syndrome

Fat emboli occur in all patients with long-bone fractures, but only few patients develop systemic dysfunction, particularly the triad of skin, brain, and lung dysfunction known as the fat embolism syndrome (FES). Here we review the FES literature under different subheadings.The incidence of FES varies from 1-29%. The etiology may be traumatic or, rarely, nontraumatic. Various factors increase the incidence of FES. Mechanical and biochemical theories have been proposed for the pathophysiology of FES. The clinical manifestations include respiratory and cerebral dysfunction and a petechial rash. Diagnosis of FES is difficult. The other causes for the above-mentioned organ dysfunction have to be excluded. The clinical criteria along with imaging studies help in diagnosis. FES can be detected early by continuous pulse oximetry in high-risk patients. Treatment of FES is essentially supportive. Medications, including steroids, heparin, alcohol, and dextran, have been found to be ineffective.

[Fat embolism during limb lengthening with a centromedullary nail: three cases]

Several methods are available for progressive limb lengthening, including centromedullary nailing, external fixation, or a combination. Each technique has its own advantages and drawbacks. In trauma victims, use of centromedullary nailing is associated with potentially fatal fat embolism. This fatal outcome might also occur during limb lengthening, particularly in bilateral procedures. To our knowledge, fat embolism has not been reported with the use of centromedullary nail for limb lengthening. This was a multicentric study of three cases of fat embolism, including one fatal outcome. In all, 36 centromedullary lengthening nails were inserted in the three centers before these acute episodes. The first two cases occurred during single-phase bilateral procedures, the third during unilateral lengthening. Fat embolism could result from several factors, as reported in the literature. While the bilateral nature of the procedure has been incriminated, the observation of an embolism during a unilateral procedure suggests other factors may be involved. Considerable increase in endomedullary pressure during reaming and insertion of the nail has been demonstrated. At the same time, there is the question as to whether the reduction of the diminution of medullary pressure by corticotomy would be an efficient way of reducing the risk of fat embolism. Based on the analysis of our three cases, we suggest that the best way to avoid fat embolism might be to drill several holes within the area of the osteotomy before reaming, in order to reduce endomedullary pressure. This can be achieved via a short skin incision, sparing the periosteum before low energy osteotomy. Since applying this protocol, the three centers have implanted 17 lengthening nails, without a single case of fat embolism.

Femoral nailing-related coagulopathy determined by first-hit magnitude: an animal study

We asked whether coagulopathy worsened during femoral intramedullary nailing in the presence of lung contusion and hemorrhagic shock and whether reamed or unreamed nailing influenced these results. In 30 Merino sheep, we induced hemorrhagic shock and/or standardized lung contusion followed by femoral nailing. Six groups of five each were assigned as follows: thoracotomy control groups treated with reamed or unreamed nailing, lung contusion groups treated with reamed or unreamed nailing, and shock and lung contusion groups treated with reamed or unreamed nailing. After lung contusion alone (first hit), the serum values of antithrombin III, factor V, and fibrinogen were considerably altered after reamed and unreamed femoral nailing (second hit) 4 hours postoperatively. In the lung contusion and shock groups, we found a substantial reduction for all serum coagulative parameters between baseline and fixation after reamed and unreamed nailing. The magnitude of the first hit is increased if hemorrhagic shock is added to a lung contusion determined by hemostatic reactions. The magnitude of the injury appears equally important as the type of subsequent surgery and should be considered in planning for fracture fixation in patients at high risk for complications.

The biological and physiological effects of intramedullary reaming

This paper summarises the current knowledge on the effects of medullary reaming of long-bone fractures. Following a review of intramedullary vascular physiology, the consequences for vascularity, the autograft effects, the generation of heat, and fat embolism are outlined. Also, alternative reaming techniques are described.

Novel technique for medullary canal débridement in tibia and femur osteomyelitis

Intramedullary infection is a challenging problem and treatment usually includes removal of infected hardware and reaming of the medullary canal. We describe a new technique for canal débridement and evaluate its infection control rate in treating osteomyelitis of the tibia and femur. We retrospectively reviewed 11 patients with posttraumatic osteomyelitis of the tibia (n = 8) or femur (n = 3). Surgery included débridement, implant removal, and reaming of the medullary canal with a new device that allows reaming under simultaneous irrigation and aspiration. At a minimum followup time of 6 months (mean, 13 months; range, 6-23 months), we observed no recurrence of infection. Complications included one partial loss of a flap, one refracture of a tibia after an automobile versus pedestrian accident, and external fixator pin tract infections in one patient. These preliminary data suggest the new reaming device may be a useful adjunct for débriding intramedullary infections of the tibia and femur.

Intramedullary canal pressure distribution: an experimental parametric study

Intramedullary instrument/device insertion during total joint replacement can generate high intramedullary pressures, with potential for clinical fat embolism syndrome. We evaluated effects of process parameters on intramedullary pressure generated when hammering an implant into a simulated femur analogue. Lower implant insertion speed, lower hammering force, a rubber- compared with steel-tipped hammer and a larger synthetic bone-to-implant radial gap reduced intramedullary pressure generated. Number of hammer strikes required to insert an implant increased with increasing marrow viscosity, whereas intramedullary pressure decreased with increasing viscosity. Significant intramedullary pressure reduction is obtained by applying more strikes of lower peak force using a rubber hammer tip, as opposed to fewer larger strikes. Caution should be exercised when instrumenting the distal femur, where viscosity is low and very high intramedullary pressures can be generated.

Early Unreamed Intramedullary Nailing of Femoral Fractures is Safe in Patients With Severe Thoracic Trauma

BACKGROUND

The timing of fixation of femoral fractures in multiply injured patients with severe thoracic trauma is discussed controversially. Some authors recommend damage control surgery, whereas other authors prefer early definitive treatment. The aim of our study was to investigate the effect of early definitive fixation of femoral fractures on outcomes in multiply injured patients with severe thoracic trauma.

METHODS

Between May 1, 1998 and December 31, 2004, 578 severely injured patients were admitted to our institution. Forty-five patients met the inclusion criteria for the study cohort (severe thoracic trauma and femoral fracture stabilized with unreamed intramedullary nailing [IMN] within the first 24 hours) and 107 patients were selected for the control cohort (severe thoracic trauma without any lower extremity fracture). Inclusion criteria for both cohorts were age 15 to 55 years with blunt trauma (e.g. motor vehicle collisions, falls) including severe thoracic trauma (Abbreviated Injury Scale [AIS] score >or=3) and Injury Severity Score (ISS) >or=18. For comparison between the cohorts data on patients status (Glasgow Coma Scale score at arrival, Revised Trauma Score, Trauma and Injury Severity Score survival prognosis, Simplified Acute Physiology Score II score), treatment (intubation rate, thoracic drainage, surgery), and outcomes (duration of intensive care unit stay and ventilation, rate of adult respiratory distress syndrome [ARDS], multiple organ failure syndrome [MOFS], and mortality) were selected from hospital databases. Dichotomous data were analyzed by chi test; continuous data were analyzed by Student's t test. Any values of p < 0.05 were considered significant for any test.

RESULTS

Both cohorts were comparable with regard to demographic data, ISS, AIS score in the thoracic region, and incidence and severity of brain injury. There was no difference in dependent parameters in both cohorts. Rates of ARDS, MOFS, and mortality were not negatively influenced by early unreamed IMN.

CONCLUSION

Early unreamed IMN of femoral fractures in multiply injured patients with severe thoracic trauma is a safe procedure and seems to be justified to achieve early definitive care.

Large animal models: baboons for trauma, shock, and sepsis studies

A few limited examples of large animal models are outlined, with the main emphasis on baboon models. The baboon offers all the advantages of a large animal and is comparable with humans in nearly all physiological and immunological aspects. In addition, cross-reactivity with human therapeutic and diagnostic reagents allows testing of new species-specific therapies such as antihuman antibodies, on the one hand, and monitoring with available human analytical procedures, on the other.

Quantitative assessment of growth factors in reaming aspirate, iliac crest, and platelet preparation

Large bony defects and non-unions are still a complication in trauma and orthopedic surgery. Treatment strategies include the use of autogenous materials (iliac crest), allogenic bone, bone substitutes, and currently stimulation with growth factors such as BMP-2, BMP-7 or the growth factors containing platelet-rich plasma (PRP). Another source of bone graft material might be the cuttings produced during intramedullary reaming. The aim of this study was to compare the quantity of various growth factors found within iliac crest, bony reaming debris, reaming irrigation fluid, and platelet-rich plasma. Iliac crest and reaming debris and irrigation samples were harvested during surgery. PRP was prepared from blood. The growth factors in the bony materials (iliac crest or reaming debris) and of the liquid materials (platelet-poor plasma (PPP), platelet-rich plasma (PRP) or reaming irrigation) were compared. Elevated levels of FGFa, PDGF, IGF-I, TGF-beta1 and BMP-2 were measured in the reaming debris as compared to iliac crest curettings. However, VEGF and FGFb were significantly lower in the reaming debris than from iliac crest samples. In comparing PRP and PPP all detectable growth factors, except IGF-I, were enhanced in the platelet-rich plasma. In the reaming irrigation FGFa (no measurable value in the PRP) and FGFb were higher, but VEGF, PDGF, IGF-I, TGF-beta1 and BMP-2 were lower compared to PRP. BMP-4 was not measurable in any sample. The bony reaming debris is a rich source of growth factors with a content comparable to that from iliac crest. The irrigation fluid from the reaming also contains growth factors.

Physical and technical aspects of intramedullary reaming

Intramedullary pressure during reaming is influenced by various factors, including those of the patient, such as bone morphology and location and type of fracture, and those related to reaming technique and instruments. Through intensive research, technical developments and the use of modern materials, intramedullary pressure caused by modern reaming systems can be reduced to a minimum and, perhaps, completely avoided through use of the reaming-irrigation-aspiration system.

Experimental background--review of animal studies

Most of the research on the physiological effects of intramedullary nailing is technically difficult or ethically impossible to perform in humans. A substantial range of factors apply in clinical cases, which means that the data obtained from this source may lack the control needed to reveal the basic mechanisms of pathophysiology associated with this surgical procedure. Consequently, animal studies have been relied upon to provide answers that would otherwise be unavailable. This review manuscript summarizes the available literature on animal studies dealing with the local and systemic effects of intramedullary nailing. It focuses on whether these studies have contributed to our clinical knowledge of the procedure's impact on perfusion and fracture healing, as well as the medical relevance of coincident systemic effects.

DATA SOURCES

Medline, personal library of the first author and of the Department of Trauma Surgery, University of Pittsburgh Medical Center.

STUDY SELECTION

All animal studies on intramedullary stabilization published in English, German, and French.

CONCLUSIONS

The relevance of animal studies investigating the impact of a surgical procedure and its influence on concomitant injuries depends on the design and the type of the animal model. If this fact is considered, and if a model is selected that simulates a systemic impact comparable with the clinical situation, then animal studies may provide a valuable source of otherwise unobtainable information. Such an example is the study of fat embolization associated with intramedullary nailing. Animal subjects enable assessment of the intervention's additive surgical impact, measurement of side effects that may have adverse results, and influence of cofactors (eg, thoracic trauma, severe shock, polytrauma) that predispose the individual to postoperative complications.

Therapeutic aspects of fat embolism syndrome

Signs and symptoms of clinical fat embolism syndrome (FES) usually begin within 24-48 hours after trauma. The classic triad involves pulmonary changes, cerebral dysfunction, and petechial rash. Clinical diagnosis is key because laboratory and radiographic diagnosis is not specific and can be inconsistent. The duration of FES is difficult to predict because it is often subclinical or may be overshadowed by other illnesses or injuries. Medical care is prophylactic or supportive, including early fixation and general ICU management to ensure adequate oxygenation and ventilation, hemodynamic stability, prophylaxis of deep venous thrombosis, stress-related gastrointestinal bleeding, and nutrition. Studies support early fracture fixation as a method to reduce recurrent fat embolism and FES. The main therapeutic interventions once FES has been clinically diagnosed are directed towards support of pulmonary and neurological manifestations and management of acute lung injury (ALI) and acute respiratory distress syndrome (ARDS).

Young, adult, and old rats have similar changes in mRNA expression of many skeletal genes after fracture despite delayed healing with age

Genes active in fracture healing are not well understood. Because age slows skeletal repair, the change in gene expression between animals of differing ages may illuminate novel pathways important to this healing response. To explore this, 6-, 26-, and 52-week-old female Sprague-Dawley rats were subjected to mid-diaphyseal femoral fracture with intramedullary fixation. The fracture callus was collected at 0, 0.4 (3 days), 1, 2, 4, or 6 weeks after fracture. RNA was extracted and pooled between two animals for each sample. Three samples were done for each time point for each age for a total of 54 Affymetrix U34A GeneChip microarrays. Of the 8700 genes on each array, 3300 were scored as present. Almost all of these genes were affected by femoral fracture with either upregulation or downregulation in the 6 weeks after fracture. Upregulated genes included markers for matrix genes for both cartilage and bone, osteoblasts, osteocytes, osteoclasts, fibroblasts, and mast cells. Downregulated genes included genes related to blood cell synthesis. Nearly all genes presently associated with bone metabolism showed the same response to fracture healing regardless of the age of the animal. In conclusion, skeletal fracture led to similar changes in RNA expression for most skeletal genes despite the delay in the formation of bone to bridge the fracture gap in old rats. Defects in the healing of skeletal trauma in older rats may lie in systems not normally studied by skeletal biologists.

Fat embolism: the reaming controversy

Intramedullary nailing is the preferred treatment method for stabilizing femoral diaphyseal fractures. Despite its superior biomechanical advantages over other implants, its use, particularly in selected groups of patients, has been questioned because of the possible harmful systemic effects of intramedullary reaming. The increase in intramedullary canal pressure during intramedullary nailing can result in intravasation of bone marrow and fat into the venous blood system. The subsequent consequences can be fat embolism syndrome (FES), adult respiratory distress syndrome (ARDS), and multiple organ failure. The lung seems to be the primary target for fat embolization and for the mediated effects primed by inflammatory reactions. In laboratory studies, both reamed and unreamed intramedullary nailing has been shown to alter selected pulmonary variables. Although transient, this effect appears to be more prominent with reamed than unreamed techniques. Additional studies are required to determine whether a subgroup of trauma patients is adversely affected by intramedullary reaming, thus necessitating other fixation techniques.

Prevention of fat embolism syndrome

Fat embolism syndrome is a condition of acute respiratory distress following long-bone trauma. This condition may involve not only the lungs but also a number of other body systems. The pathophysiology is not as yet clearly understood, however, intravasation of fat from long-bone fractures may play a role. Early recognition of the severity of injury both on clinical and biochemical grounds and early surgical stabilization of long bones may help to decrease its incidence. However, the best surgical technique with which to do this stabilization has not yet been clearly determined. Surgical and pharmacological techniques have been developed in an attempt to either decrease the intravasation of fat during long-bone stabilization or block the inflammatory cascade with varying degrees of efficacy. Ongoing research focuses on both the prevention and treatment of this condition.

Pathophysiological advantages of rinsing-suction-reaming (RSR) in a pig model for intramedullary nailing

Although reamed intramedullary nailing has been one of the greatest advances in modern fracture care, the concomitant increase in medullary cavity pressure leads to intravasation of bone marrow content into the blood stream, an effect that can evoke serious systemic reactions. A newly developed rinsing-suction-reamer (RSR) was able to substantially reduce the pressure and bone marrow intravasation content during experimental femoral nailing. We investigated the pathophysiological effects using the RSR, testing the hypothesis that by reducing marrow fat embolization, RSR would also reduce the activation of coagulation compared with the universal AO-Reamer (AOR) and comparable to external fixation. Twenty-two pigs were treated with either simulated external fixation or reamed femoral nailing using AOR or RSR. During surgery, the intramedullary pressure was measured and intravasation of medullary material was quantified. After surgery, the pigs were kept anaesthetised and monitored for 6 h. At defined intervals, serological, hematological, and hemodynamic parameters were evaluated. The RSR was significantly superior when compared to AOR with regard to the generation of intramedullary pressure and fat embolization; however, with external fixation the values were even lower. The evaluation of other parameters revealed no clear differences between the two reamers and the external fixator. The pig model showed that RSR led to a significant reduction of the intramedullary increase in pressure and fat intravasation compared to AOR. Although the reduction of fat embolism by RSR is not associated with pathophysiological changes, RSR can have advantages for the treatment of femoral fractures.

Pressurization of the Metastatic Femur During Prophylactic Intramedullary Nail Fixation

BACKGROUND

Venting during prophylactic nailing of metastatic femoral lesions may decrease intramedullary pressures and the risk of fat and tumor embolization. This study aimed to quantify maximum intramedullary pressure levels and durations, and to examine tumor displacement during prophylactic reamed intramedullary nailing of vented and nonvented metastatically involved femora.

METHODS

Proximal metastatic defects were simulated in six pairs of cadaveric femora and prophylactically treated using reamed intramedullary nailing with or without proximal and distal vents. Maximum pressures, durations of pressure exceeding embolic threshold levels (25 and 200 mm Hg), and tumor displacement were recorded.

RESULTS

Maximum pressures and durations of pressure exceeding embolic thresholds decreased more than 50% with venting (p < 0.05). Distal pressures surpassed the 25-mm Hg threshold even with venting. Post-test sectioning showed increased tumor disbursement in vented specimens.

CONCLUSIONS

Venting reduces pressurization during prophylactic reamed intramedullary nailing of femoral metastases, but may increase the spread of tumor to extraskeletal tissue if vented tissue is not contained.

Rinsing-Suction Reamer Attenuates Intramedullary Pressure Increase and Fat Intravasation in a Sheep Model

BACKGROUND

Reamed intramedullary nailing causes an increase of intramedullary pressure. A new rinsing-suction reamer (RSR) can reduce this problem, and it was evaluated in animal experiments in comparison with the AO reamer (AOR) to see its effects on intramedullary pressure and fat intravasation.

METHODS

Reamed intramedullary nailing was performed in 14 sheep using the RSR or AOR. The following parameters were evaluated: intramedullary pressure, hemodynamics, blood tests, lung histology, and radiographs of the femur that was operated on.

RESULTS

Intramedullary pressure during reaming was significantly (p < 0.001) lower with RSR (9 mm, 34 mm Hg; 9.5 mm, 4 mm Hg; 10 mm, 1 mm Hg) than AOR (9 mm, 750 mm Hg; 9.5 mm, 292 mm Hg; 10 mm, 138 mm Hg). There was a significantly (p < 0.05) higher increase of pulmonary resistance in AOR (from 144 +/- 84 dyne x s x cm to 391 +/- 169 dyne x s x cm) than in RSR (from 137 +/- 51 dyne x s x cm to 258 +/- 105 dyne x s x cm) after nailing and less intravenous fat measured in RSR (0.9; AOR, 2.9; p < 0.05) at all stages of reaming, at nail insertion (RSR, 0.3; AOR, 2.7; p < 0.05), and 30 seconds after nail insertion (RSR, 0.2; AOR, 1.1; p < 0.05) proved by the Gurd test. Pco2 increased (p < 0.05) in AOR (AOR, 36 +/- 5 vs. 40 +/- 7 mm Hg; RSR, 33 +/- 4 vs. 32 +/- 3 mm Hg) and pH dropped significantly (AOR, 7.49 +/- 0.06 vs. 7.45 +/- 0.05; RSR, 7.53 +/- 0.04 vs. 7.54 +/- 0.04; p < 0.05). Semiquantitative histologic analysis proved a significant higher pulmonary fat load in AOR (13.1 +/- 13.4) versus RSR (3.9 +/- 1.5, p = 0.00002).

CONCLUSION

Because we found only a minimal increase of the pulmonary arterial pressure as a sign of pulmonary embolism, we conclude that by using the RSR, the systemic side effects caused by intravasation of medullary content during reaming could be reduced as far as possible.

Biochemical characterization of individual injury pattern and injury severity

BACKGROUND

Estimation of trauma severity currently relies on clinical diagnoses and scoring systems. However, the early estimation of the severity of chest trauma and overall soft tissue trauma (STT) remains insufficient. Traditional trauma scoring systems fail to reflect the individual trauma pattern and severity, neglecting the different outcomes after injuries in different body regions. Therefore, the aim of this prospective study was to detect laboratory markers that may reflect the pattern and extent of individual trauma in the very early phase after injury.

PATIENTS AND METHODS

In 107 non-selected trauma patients, blood samples were collected almost immediately and then at short intervals after the trauma. In addition to the biochemical analysis of 20 different mediators viewed as potential trauma markers, the following data were correlated with the laboratory results: injury severity score (ISS), polytrauma score (PTS), Ulmer score HTAPE (trauma pattern specific: head (H), thorax (T), abdomen (A), pelvis (P), extremities (E); 0-3 degrees each), multiple organ failure score (MOF), overall, primary and secondary lethality.

RESULTS

ISS and the severity of head injury were clearly higher in non-survivors (n=17) than in survivors (n=90) (median ISS: 35 versus 18; median severity of head injury (H): 3 versus 1). Whereas head injury was correlated with early death (<or=3 days: r=0.45), late death (>3 days post-trauma) was influenced by thoracic trauma (r=0.15) as well as by soft tissue trauma (STT, r=0.12). Of all investigated mediators, interleukin-6 (IL-6) displayed the highest correlations (r=0.66, P<0.00001) with the extent of chest trauma, followed by correlations with PTS, STT, fracture trauma (FT) and ISS during the first hour after trauma. There was no correlation between IL-6 and head injury. The extent of STT was correlated best to IL-8 (r=0.75), IL-6 (r=0.54), and creatine kinase (CK, r=0.49) plasma concentrations.

CONCLUSION

In the very early stage after an accident the severity of chest trauma is strongly correlated with the plasma concentration of IL-6, and the extent of overall soft tissue trauma (STT) to plasma concentrations of IL-8, IL-6, and CK.

Cardiopulmonary complications of intramedullary fixation of long bone metastases

Intramedullary fixation of long bone metastases is an effective method of treating or preventing pathologic fractures. An important complication of this technique is the development of pulmonary embolism, which may occur at any number of steps during bone manipulation. Passage of normal marrow contents or tumor into the pulmonary circulation is thought to cause various biochemical, hemodynamic, or physical responses that lead to hypotension, arrythmia, and O2 desaturation. Death is a known risk of this procedure. Numerous surgical and anesthetic strategies have been developed to prevent or treat pulmonary embolic phenomena; however, the most important prophylaxis may be a heightened awareness of this possibility during any procedure that involves intramedullary manipulation of tumor containing bone.