Emanuel Benninger

C-clamp and pelvic packing for control of hemorrhage in patients with pelvic ring disruption

Background: Exsanguinating hemorrhage is the major cause of death in patients with pelvic ring disruption. Aims: The aim of this study was to document outcomes after the stabilization of pelvic ring injuries by a C-clamp and control of hemorrhage by pelvic packing. Physiological parameters were tested as prognostic factors. Setting and Design: This was a retrospective study at a level I trauma center. The study period was from January 1996 to December 2007. Materials and Methods: Fifty patients with pelvic ring disruption and hemorrhagic shock were analyzed. The pelvic rings were fixed by a C-clamp, and patients with ongoing hemorrhage underwent laparotomy and extra- and/or intra-peritoneal pelvic packing. Clinical parameters (heart rate, mean arterial pressure) and physiological parameters (lactate levels, hemoglobin, hematocrit) were documented at admission and at different time points during the initial treatment (1, 2, 3, 4, 6, 8, and 12h after admission). Results: Within 12 h of admission, 16 patients died (nonsurvivors) due to hemorrhagic shock (n=13) or head injuries (n=3). In this group, 12 patients underwent laparotomy with pelvic packing. Thirty-four patients survived the first 12 h (early survivors) after fixation by a C-clamp and additional packing in 23 patients. Four of these patients died 12.3±7.1 days later due to multiple organ failure (n=3) or severe head injury (n=1). The blood lactate level at admission was significantly higher in the group of nonsurvivors (7.2±0.8 mmol/L) compared to the early survivors (4.3±0.5 mmol/L, P<0.05). While hemoglobin values improved within the first 2 h in nonsurvivors, lactate levels continued to increase. Conclusion: Pelvic packing in addition to the C-clamp fixation effectively controls severe hemorrhage in patients with pelvic ring disruption. Early sequential measurements of blood lactate levels can be used to estimate the severity of shock and the response to the shock treatment.

Inferior Results of Salvage Arthrodesis After Failed Ankle Replacement Compared to Primary Arthrodesis

Background: Up to now, there has been no evidence that salvage arthrodesis would perform inferior when compared with primary ankle arthrodesis. The purpose of this study was to compare their clinical and radiographic results. Methods: A retrospective analysis was performed using 2 validated scores and assessment of radiographic union by comparing 23 patients who underwent salvage ankle arthrodesis (group SA = salvage arthrodesis) after failed total ankle replacement with 23 matched patients who received primary ankle arthrodesis (group PA = primary arthrodesis). The mean follow-up period was 38 (range 16-92) months in group SA and 56 (23-94) months in group PA. Results: Complete union was achieved in 17 patients (74%) after a mean time of 50 (13- 114) weeks in group SA and in 16 patients (70%) after a mean time of 23 (10-115) weeks in group PA. The SF-36 score averaged 48 points (7-80) in SA and 66 points (14-94; P = .006) in group PA. In group SA the mean FFI was 57% (22-82) for pain and 71% (44-98) for function. In group PA significantly better results for pain with 34% (0-88; P = .002) and function with 48% (1-92; P = .002) were found. Conclusion: Salvage arthrodesis led to impaired life quality and reduced function combined with significantly higher pain when compared with primary ankle arthrodesis. These findings can be used to counsel our patients preoperatively. Level of Evidence: Level III, retrospective case series.

Intra-abdominal pressure development after different temporary abdominal closure techniques in a porcine model

BACKGROUND Decompressive laparotomy followed by temporary abdominal closure (TAC) is an established prophylaxis and treatment for abdominal compartment syndrome. The herein presented study aimed at the comparison of volume reserve capacity and development of intra-abdominal hypertension after forced primary abdominal closure and different TAC techniques in a porcine model. METHODS Eight anesthesized and mechanically ventilated domestic pigs underwent a standardized midline laparotomy. A bag was placed into the abdominal cavity. Before abdominal closure, the bag was prefilled with 3,000 mL water to simulate increased intra-abdominal volume. The intra-abdominal pressure (IAP) was then increased in 2 mm Hg steps up to 30 mm Hg by adding volume (volume reserve capacity) to the intra-abdominal bag. Volume reserve capacity with the corresponding IAP were analyzed and compared for primary abdominal closure, bag silo closure, a zipper system, and vacuum-assisted closure (VAC) with different negative pressures (-50, -100, and -150 mm Hg). Hemodynamic and pulmonary parameters were monitored throughout the experiment. RESULTS Volume reserve capacity was the highest for bag silo closure followed by the zipper system and VAC with primary abdominal closure providing the least volume reserve capacity in the whole IAP range. Of interest, VAC -50 mm Hg resulted in a lower volume reserve capacity when compared with VAC -100 and -150 mm Hg. Pulmonary and hemodynamic parameters demonstrated no significant differences between primary abdominal closure and the evaluated TAC techniques at all IAP levels. CONCLUSIONS The present experimental in vivo study indicates that bag silo closure and zipper systems may be favorable TAC techniques after decompressive laparotomy. In contrast, the VAC techniques resulted in lower volume reserve capacity and therefore may bear an increased risk for recurrent intra-abdominal hypertension in the initial phase after decompressive laparotomy.

Early detection of subclinical organ dysfunction by microdialysis of the rectus abdominis muscle in a porcine model of critical intra-abdominal hypertension.

ABSTRACT The aim of this study was to evaluate microdialysis of the rectus abdominis muscle (RAM) for early detection of subclinical organ dysfunction in a porcine model of critical intra-abdominal hypertension (IAH). Microdialysis catheters for analyses of lactate, pyruvate, and glycerol levels were placed in cervical muscles (control), gastric and jejunal wall, liver, kidney, and RAM of 30 anesthetized mechanically ventilated pigs. Catheters for venous lactate and interleukin 6 samples were placed in the jugular, portal, and femoral vein. Intra-abdominal pressure (IAP) was increased to 20 mmHg (IAH20 group, n = 10) and 30 mmHg (IAH30, n = 10) for 6 h by controlled CO2 insufflation, whereas sham animals (n = 10) exhibited a physiological IAP. In contrast to 20 mmHg, an IAH of 30 mmHg induced pathophysiological alterations consistent with an abdominal compartment syndrome. Microdialysis showed significant increase in the lactate/pyruvate ratio in the RAM of the IAH20 group after 6 h. In the IAH30 group, the strongest increase in lactate/pyruvate ratio was detected in the RAM and less pronounced in the liver and gastric wall. Glycerol increased in the RAM only. After 6 h, there was a significant increase in venous interleukin 6 of the IAH30 group compared with baseline. Venous lactate was increased compared with baseline and shams in the femoral vein of the IAH30 group only. Intra-abdominal pressure–induced ischemic metabolic changes are detected more rapidly and pronounced by microdialysis of the RAM when compared with intra-abdominal organs. Thus, the RAM represents an important and easily accessible site for the early detection of subclinical organ dysfunction during critical IAH.

The Varus Ankle and Instability

Varus ankle associated with instability can be simple or complex. Multiple underlying diseases may contribute to this complex pathologic entity. These conditions should be recognized when attempting proper decision-making. Treatment options range from conservative measures to surgical reconstruction. Whereas conservative treatment might be a possible approach for patients with simple varus ankle instability, more complex instabilities require extensive surgical reconstructions. However, adequate diagnostic workup and accurate analysis of varus ankle instability provide a base for the successful treatment outcome.

Bogota-VAC – A Newly Modified Temporary Abdominal Closure Technique

Background:We present Bogota-VAC, a newly modified temporary abdominal closure (TAC) technique for open abdomen condition after abdominal compartment syndrome (ACS).Methods:A thin isolation bag (Bogota bag) and a vacuum assisted closure (VAC) system were combined. A matching bag was tension-free fixed on the abdominal fascia by fascia suture. A ring shaped black polyurethane foam of the VAC system was placed into the gap between Bogota bag, abdominal fascia and the wound edge. A constant negative topic pressure of 50–75 mmHg was used in the VAC system.Results:Intra-abdominal pressure (IAP: 22 ± 2 mmHg) of four patients with ACS after severe traumatic brain injury and one patient with isolated ACS after blunt abdominal trauma decreased significantly (p = 0.01) after decompressive laparotomy and treatment with Bogota-VAC (IAP: 10 ± 2 mmHg) and remained low, measured via urinary bladder pressure. Intracranial pressure (ICP) in the four traumatic brain injury patients decreased from 42 ± 13 mmHg to 15 ± 3 mmHg after abdominal decompression. Cerebral perfusion pressure (57 ± 14 mmHg) increased to 74 ± 2 mmHg.Conclusion:The advantage of the presented Bogota-VAC is leak tightness, wound conditioning (soft tissue/fascia), skin protection and facilitation of nursing in combination with highest volume reserve capacity (VRC), thus preventing recurrent increased intra-abdominal and intracranial pressure in the initial phase after decompression of ACS compared to other TAC techniques.

How many radiographs are needed to detect angular stable head screw cut outs of the proximal humerus - A cadaver study

INTRODUCTION Cut out of locking head screws is the most common complication of locking plates in fracture fixation of the proximal humerus with potentially disastrous consequences. Aim of the study was to find the single best and combination of radiographic projections to reliably detect screw cut outs. MATERIALS AND METHODS The locking plate was fixed to six cadaveric proximal humeri. Six different radiographs were performed: anteriorposterior in internal (apIR), in neutral (ap0) and in 30° external rotation (apER); axial in 30° (ax30) and 60° (ax60) abduction and an outlet view. Each head screw (n=9) was sequentially exchanged to perforate the humeral head with the tip and all radiographs were repeated for each cut out. Randomized image reading by two blinded examiners for cut out was done for single projection and combinations. RESULTS Interrater agreement was 0.72-0.93. Best single projection was ax30 (sensitivity 76%) and the worst was the outlet view (sens. 17%). Standard combination of apIR/outlet reached a sens. of 54%. The best combination of two was: apER/ax30 (90% sens.), of three: apIR/apER/ax30 (96% sens.) and of four: apIR/ap0/apER/ax30 (100% sens.). CONCLUSION Standard radiographs (ap/outlet), especially in internal rotation, may miss nearly half of screw cut outs. Single best radiographic projection was an axial view with 30° abduction. To account for all cut outs and correct screw position a combination of four projections was needed. These simple and feasible intraoperative and postoperative radiographs help to detect screw perforations of the locking plate reliably. LEVEL OF EVIDENCE I (Study of Diagnostic Test).

Primary stability and stiffness in ankle arthrodes-crossed screws versus anterior plating.

BACKGROUND Ankle arthrodesis is commonly used for the treatment of osteoarthritis or failed arthroplasty. Screw fixation is the predominant technique to perform ankle arthrodesis. Due to a considerable frequency of failures research suggests the use of an anatomically shaped anterior double plate system as a reliable method for isolated tibiotalar arthrodesis. The purpose of the present biomechanical study was to compare two groups of ankle fusion constructs - three screw fixation and an anterior double plate system - in terms of primary stability and stiffness. METHODS Six matched-pairs human cadaveric lower legs (Thiel fixated) were used in this study. One specimen from each pair was randomly assigned to be stabilized with the anterior double plate system and the other with the three-screw technique. The different arthrodesis methods were tested by dorsiflexing the foot until failure of the system, defined as rotation of the talus relative to the tibia in the sagittal plane. Experiments were performed on a universal materials testing machine. The force required to make arthrodesis fail was documented. For calculation of the stiffness, a linear regression was fitted to the force-displacement curve in the linear portion of the curve and its slope taken as the stiffness. RESULTS For the anatomically shaped double-plate system a mean load of 967N was needed (range from 570N to 1400N) to make arthrodesis fail. The three-screw fixation method resisted a mean load of 190N (range from 100N to 280N) (p=0.005). In terms of stiffness a mean of 56N/mm (range from 35N/mm to 79N/mm) was achieved for the anatomically shaped double-plate system whereas a mean of 10N/mm (range from 6N/mm to 18N/mm) was achieved for the three-screw fixation method (p=0.004). CONCLUSIONS Our biomechanical data demonstrates that the anterior double-plate system is significantly superior to the three-screw fixation technique for ankle arthrodesis in terms of primary stability and stiffness.

Endostatin inhibits Callus remodeling during fracture healing in mice.

Information on the impact of endogenous anti‐angiogenic factors on bone repair is limited. The hypothesis of the present study was endostatin, an endogenous inhibitor of angiogenesis, disturbs fracture healing. We evaluated this hypothesis in a closed femoral fracture model studying two groups of mice, one that was treated by a daily injection of 10 µg recombinant endostatin subcutaneously (n = 38) and a second one that received the vehicle for control (n = 37). Histomorphometric analysis showed a significantly increased callus formation in endostatin‐treated animals at 2 and 5 weeks post‐fracture. This was associated with a significantly higher callus tissue fraction of cartilage and fibrous tissue at 2 weeks and a significantly higher fraction of bone at 5 weeks post‐fracture. Biomechanical testing revealed a significantly higher torsional stiffness in the endostatin group at 2 weeks. For both groups, we could demonstrate the expression of the endostatin receptor unit integrin alpha5 in endothelial cells, osteoblasts, osteoclasts, and chondrocytes at 2 weeks. Immunohistochemical fluorescence staining of CD31 showed a lower number of blood vessels in endostatin‐treated animals compared to controls. The results of the present study indicate endostatin promotes soft callus formation but inhibits callus remodeling during fracture healing most probably by an inhibition of angiogenesis.

Base excess determined within one hour of admission predicts mortality in patients with severe pelvic fractures and severe hemorrhagic shock

AbstractBackground:Unstable pelvic ring fractures with exsanguinating hemorrhages are rare but potentially lifethreatening injuries. The aim of this retrospective study was to evaluate whether early changes in acid– base parameters predict mortality of patients with severe pelvic trauma and hemorrhagic shock.Methods:Data for 50 patients with pelvic ring disruption and severe hemorrhage were analyzed retrospectively. In all patients, the pelvic ring was temporarily stabilized by C-clamp. Patients with ongoing bleeding underwent laparotomy with extra and/or intraperitoneal pelvic packing, as required. Base excess, lactate, and pH were measured upon admission and at 1, 2, 3, 4, 6, 8, and 12 h postadmission. Patients were categorized as early survivors (surviving the first 12 h after admission) and nonsurvivors. Statistical analysis was performed by Mann-Whitney test; significance was assumed at p < 0.05. Receiver operating characteristic curves were generated for early mortality from each acid–base variable.Results:Sixteen patients (32%) were nonsurvivors due to hemorrhagic shock (n = 13) or severe traumatic brain injury (n = 3). Thirty-four patients were early survivors. Base excess, lactate, and pH significantly discriminated between early survivors and nonsurvivors. Base excess determined 1 h after admission discriminated most strongly, with an area under the receiver operating characteristic curve of 0.915 (95% confidence interval, 0.836–0.993; p < 0.001).Conclusion:Base excess, lactate, and pH discriminate early survivors from nonsurvivors suffering from severe pelvic trauma and hemorrhagic shock. Base excess measured 1 h after admission best predicted early mortality following pelvic trauma with concomitant hemorrhage.