Pre-peritoneal Pelvic Pack with External Fixator versus Pelvic Pack Alone for Hemodynamically Unstable Patients with Pelvic Fracture; a Historical Cohort Study

Pelvic fracture is one of the most common cause of death in traumatic patients. This study was designed to compare the outcome, morbidity and complications of treatment with pre-peritoneal pelvic pack with external xator against pelvic pack alone in traumatic pelvic fracture and unstable hemodynamic patients. In a retrospective case control study, patients with pelvic and unstable hemodynamic who and 2018 2019 were enrolled by census manner. In the control group, 25 patients treated just by a pre-peritoneal pack (PPP group), while in the case group, pre-peritoneal pack and external xator was done as the procedure to control bleeding (PPP Plus xator group) in 22 individuals. Two groups were compared for presence of thromboembolism, hospital stay, infection, BUN, creatinine, rate of blood transfusion and mortality.


Introduction
Pelvic fracture is one of the most common cause of death in traumatic patients and estimating for at least 5% of fractures. It is also reported in a large number of patients with multiple trauma (1). It is due to high-energy trauma, which is associated with damage to other organs, like chest and abdomen (2).
Approximately 80% of patients who develop severe hemorrhagic shock after a high-energy trauma die in the early stages, even before hospitalization (3). Unstable hemodynamic state due to pelvic fracture needs early xation which supposed as a part of the resuscitation (4).
Young classi cation was established according to risk of bleeding, enabling the surgeon to detect associated injuries. Type-1 representing Antero-posterior compression, which is likely to damage the internal iliac artery. Type-2 indicating Lateral compression, which is likely to be retro pubic. Type-3 which is about vertical shearing. The risk of bleeding depends on the type and severity of the lesion (2,5). Pelvic fracture and unstable hemodynamic condition is one of the most important problems in the management of trauma. It can cause extensive bleeding, renal failure, thromboembolism and other fatal complications.so, early detection and xation are two important parts of management (6).
The most common site of bleeding is the venous plexus and cancellous bone surfaces and arterial rupture is less common (2). The beginning treatment of these patients must emphasize on controlling hematoma rapidly. Fast xation of fracture and con guration of accompanying trauma is critical.
Individuals with unstable pelvic fracture can be treated by an anterior pelvic xator or posterior pelvic Cclamp (7). Another way in this situation is Pelvic Peritoneal Packing (PPP). Packing is done by anterior approach and depletion of hematoma. Three packs are pushed gradually to the pelvic brim. The rst pack should put in the inferior part of Sacro-iliac joint, the second one should be placed in the anterior part of Pelvic edge and the last band should be in the retro pubic situation (8). Emergent arteriography and embolization would be mentioned, if hemorrhage is continuous (9).
A recent guideline was reported the stepwise approach of unstable pelvic fracture. The experts believed that embolization should be mentioned when the hematoma was not due to pelvic origin. If the evidence of arterial disturbance in the intravenous contrast CT scan was proved, embolization is needed without mentioning hemodynamic situation (10). In some studies, pelvic peritoneal packing (PPP) with external xator was established as the mainstay in treatment, while some others used PPP with C-Clamp in according with external xator (11,12). There is no evidence about comparing different types of surgeries. This study was designed to compare the outcome, morbidity and complications of treatment with pre-peritoneal pelvic plexus with external xator against pelvic packing alone treatment in traumatic pelvic fracture and unstable hemodynamic patients.

Materials And Methods
In a retrospective case control study, patients with pelvic fracture and unstable hemodynamic state who referred to emergency and surgery department of a level I trauma center from August 2018 to August 2019 were enrolled by census manner. Sample selection was done by random allocation and all data from patients' recordings were evaluated. In the control group, 25 patients treated just by a pre-peritoneal pack (PPP group), while in the case group, pre-peritoneal pack and external xator was done as the procedure to control bleeding (PPP Plus xator group) in 22 individuals. Patients who had damage to anterior part of pelvic managed by external xator in the iliac crest and supra acetabulum. After con rming good union in the site of fracture the external xator was removed which may last approximately one month and weight bearing according to type of fracture was permitted.
All study procedures and data gathering was approved by the committee of ethics in authors' a liated hospital; two groups were compared for presence of thromboembolism, hospital stay, infection, BUN, creatinine, rate of blood transfusion and mortality. All data gathered by blinded examiners in the course of hospitalization from three to 7 days of admission. Acute kidney injury (AKI) was mentioned as one of these two criteria; increasing creatinine up to 50% from the baseline within 48-hour, decreasing urine output less than 300 cc/kg which lasts at least 6 hours. BUN and creatinine was measured every day or every other days in the length of hospitalization.
Infection was determined as obvious pus from site of surgery, systemic sepsis which de ned by high grade fever and a site of infection in pelvis. All the patients evaluated by the same blinded senior resident for evidences of infections. The patients were evaluated 12 weeks after admission for evidences of venous thrombo-embolic events (VTE) either DVT (Deep vein thrombosis) or PTE (Pulmonary thromboembolism) during the treatment period.

Results
Mean age of participants were 34.48 ± 13.79 in pelvic pack group, while it was reported 32.36 ± 16.29 in PPP plus external xator ones (Table 1). There were no signi cant difference between two groups (p = 0.481) and fortunately two groups were similar in age groups. In another demographic data, most of the patients were men in both groups; 76% in control groups and 77.3% in PPP plus external xator patients (Fig. 1). Analytic tests did not show any difference between two groups. This means both groups were similar according to gender frequency and males were signi cantly more than females (p = 0.01). There was no signi cance between type of surgery and changing in values of BUN and creatinine. Acute kidney injury was reported in 6 (24%) individuals of PPP group, while its rate in PPP plus xator group was 40.9%.P-value was reported 0.215 in the Chi-Square test and both groups did not have signi cant difference in AKI complications. Infection was reported in 6(27.3%) case groups, while it was declared in 3 (12%) PPP group. There was no signi cant difference between two groups according to infectious events (p = 0.184) ( Table 2).

Discussion
This clinical trial was done on 47 patients with pelvic fracture who were unstable according to their hemodynamic evaluations. Among them 25 patients were managed by packing in pre-peritoneal portion, while 22 ones were treated by preperitoneal pack and external xator. The patients were similar in demographic data including age and gender. This similarity can increase the internal validity of our study, because mortality and complications can rise in older patients. In both groups the main gender were males and this signi cant data also helped us to generalize our data because of most of the people who were evaluated due to pelvic fracture are males. In a new survey which was done to evaluate the unstable pelvic fractures in Taiwan the majority of patients were males and the most age speci c group in this investigation was reported between 46-65 years old (14). Our data was similar to this and other appropriate studies in according to the mean age and gender of participants.
Mean of Injury Severity Score (ISS) was measured 23.12 ± 9.85 and 19.22 ± 8.09 in Pelvic Pack group and PPP plus external xator group, respectively. This score was approximately similar to Schweigko er et al. (15). Mean of hospital stay was not signi cant between two different types of operations. Malik et al reported the hospital stay more than 9 days for their cases. This study estimated the length of hospital stay less than our study (16). The patients in Malik study were managed by xator and it may be the cause of difference between its hospital stay and ours. There was no signi cance between types of surgery and changing in values of BUN and creatinine. Some studies (17,18) reported the acute kidney injury as an important complication in pelvic fracture who are unstable, but because of operation in all of patients in our study the prevalence of AKI was rare.
There was a signi cant difference between groups (P-Value = 0.017, LR = 6.42) in according to mortality rate. This result shows that using Pre-peritoneal packing with external xator is more effective to decrease mortality rate in comparison with pre-peritoneal packing alone. In case group, the patients divided into two groups according to the time of external xator replacement. In 6 patients the external xator was placed within 2 days and in 16 ones the surgery was done after 2nd day of admission. One Mortality was reported in patients who were treated by external xator within rst 48 hours of admission, while it was not reported in cases who treated after 48 hours of admission.
Cothren and et al. declared that PPP is a fast manner for preventing hemorrhagic shock due to pelvic fracture and this treatment can be completed by angiography. Need of blood and its production transfusion and mortality rate was dramatically decreased after this type of surgery (4). Guthrie et al.
mentioned that embolization via angiography was not a rapid way to control homeostasis in some medical centers and pelvic packing is able to decrease blood loss. Packing may be placed either retroperitoneal or pre-peritoneal. They believed that using external xator can magnify the effects of packing in bleeding control (19).
Ertel et al. reported 20 patients with unstable situation due to pelvic fracture because of multiple trauma in a prospective investigation. They used hemoglobin, hematocrit and lactate to compare hemorrhagic shock in these patients. They found that pelvic packing with external xator placement can be a more useful method to control bleeding (20). Roman Pavic and et al. concluded that the most effective therapeutic method for treatment of pelvic fracture is using external xator or C-Clamps for immobilization. They declared that embolization can be used if these methods do not work (21). Artoni et al reported that Pelvic fractures due to multiple trauma which was managed by early surgical operation can be more effective and has less reduction in quality of life (22). This study was different about our study; they believed that early surgery as soon as possible can affect outcomes, while mortality was not reported in patients who were operated after 48 hours. This maybe because of using pack cell and hydration in our management which may better the outcome and decrease the mortality rate.
VTE was reported 12% and 4.5% in PPP group and PPP plus xator ones, respectively. There was not signi cant in VTE reports, too. Many studies mentioned that VTE is a prevalent complication among individuals who had hemodynamic instability due to pelvic fracture (23,24). In this study common morbidity and mortality rate of two different therapeutic approaches were investigated in patients with pelvic fracture and unstable hemodynamic state. AKI, infection and VTE were not signi cantly different between two types of treatment. Our study declared that pre-peritoneal pelvic pack with external xator was more effective in decreasing mortality rate in comparison to pre-peritoneal pelvic pack without any xator. The investigation did not mention the best time for place external xator. According to data from our study and similar investigations which were discussed above, using external xator along with pre-peritoneal packing can be more useful in controlling blood loss and decreasing mortality rate. One of our unique methodology was dividing placement of external xator into two groups; within 48 hours and after 48 hours. Results did not show any relation between time of xation and mortality rate.

Conclusion
It was concluded that using external xator with PPP can be a useful method for treatment of pelvic fracture that is unstable in hemodynamic situation. It is recommended to use biomarkers like lactate or others to determine the situation of patients as precise as possible.

Declarations
Ethics approval and consent to participate The study protocol was approved by the institutional review board and medical ethics committee of the Baqiyatallah University of Medical Sciences (IR.BMSU.REC.1397.196).

Consent for publication
Not applicable

Availability of data and material
The data material of the study is available in SPSS le and would be available on request.

Competing interests
None of the authors have any con ict of interest to declare regarding the study.

Funding
The study was supported by a Grant from the Shiraz University of Medical Sciences.
Authors' contributions HK: Concept and design; supervision; data interpretation; critically revising the manuscript SP: Concept and design; data interpretation; approving the nal draft MA: Data gathering; analysis of the data; drafting the manuscript