A Research About Modified Stoppa Approach Internal Fixation Versus External Fixator In The Treatment Of Anterior Pelvic Ring Fracture

Background and objectivesPelvic ring is composed of bones and ligaments, as well as sacroiliac joint and symphysis pubis. It plays an important role in the connection of spine and the main weight-bearing structure, which can transmit the force of sitting, walking and running to the spine. The anterior tension elbow is made up of anterior pelvic ring, which could be broken by the forces from any direction. So that it would lead to the anterior pelvic fracture. The posterior ring would remain intact until the force beyond the capacity of the anterior ring and posterior ligaments. Therefore, anterior pelvic ring fracture is more common than the posterior ring fracture. Serious injuries of the pelvic ring could not only lead to bone fractures and instability of pelvic, but also cause the organs and neurovascular injury in the pelvic, which would result in peritonitis and nerve injury, or even hemorrhea. The mortality of pelvic fractures accounts for 5% to 42%, and the disability is much higher than the mortality. Moreover, inappropriate treatment could also lead to high incidence of mal-union, chronic pain, abnormal gait, neurovascular injury.The treatments of pelvic fractures include nonsurgical treatment, external fixation, open reduction and internal fixation (ORIF) and percutaneous screw fixation. Indication and goal of these treatments are not the same.Nonsurgical treatment can be used to treat the stable pelvic fractures. For example, the superior pubic ramus fracture has no effect on the stability of the pelvic, so that it could treat conservatively.Few reports demonstrated that percutaneous screw fixation can only appry in simple pelvic fractures, with a rate of failure of 6% to 15%. In addition, there are same disadcantages. First of all, direct reduction can’t be achieved. Secondly, the percutaneous plate is difficult to precounter. Lastly, reoperation must be perform to remove the plate after the bone union, which would cause secondary injury.Most of the surgeons recommend ORIF to treat anterior pelvic fracture in order to correct displacement of bone fragment, restore the pelvic structure and maintain stability of pelvic by rigid fixation, so that the patient could receive early rehabilitation and reduce the disability and mortality. Recently, the modified Stoppa approach became the most common approach for the treatment of anterior pelvic ring fractures through open reduction and interal fixation. The Stoppa approach used for repairing hernia was introduced by Hirvensalo in 1993 to overcome the disadvantages of lioinguinal approach in the treatment of pelvic fractures successfully, with simplify procedure and minimally invasive incision. In 1994, Cole and Bolhofner introduced a modified Stoppa approach to treat acetabular fracture through a 10cm incision of midline of abdomen. The operation was performed extraperitoneally, with the fully exposure of quadrilateral surface, simple procedure, low rate neurovascular injury and heterotopic ossification. There is no need to expose the femoral nerve and vessels. The modified Stoppa approach is also superior on the treatment of both sides of anterior pelvic fractures, which can reduce operative time and trauma According to some reports, the result of reduction in ORIF through Stoppa approach for pelvic fractures and acetabular fracture is 83%～100% and 84% ～95%, and the rate of heterotopic ossification was 0～0.7% without sciatic nerve injury. In the treatment of anterior pelvic fractures, modified Stoppa approach has the advantages of small incision, easy for visualization and reduction, low complication rate and rapid rehabilitation.The treatment of external fixation aims at rescuing life by correcting pelvic deformity, restoring pelvic volume, controlling bleeding, and anti-stock, so that the patient could survive before comprehensive examination and management of the injury. However, the friction between skin and frame, inconvenience and pins infections are the most common complication. Moreover, some cases needs to reoperation because of the unsatisfied reduction. Therefore, external fixation for treating pelvic fracture is challenging.Therefore, what is the optimal emergency treatment for anterior pelvic fractures is still controversial We retrospectively collected patients, who sustained anterior pelvic fracture and treated in our hospital, to compare the functional outcomes and complications between interal fixation through modified Stoppa approach and external fixation in the treatment of pelvic fractures, we retrospectively evaluated the functional outcomes between interal fixation through modified Stoppa approach and external fixation.Methods1. SubjectsAnterior pelvic fracture patients treated by ORIF through the modified Stoppa approach or external fixation was collected from March 2009 to June 2014. There was no significant difference in gender, age, weight, type of fractures or mechanism of Injury between patients who underwent modified Stoppa approach those underwent external fixation(p>0.05).Modified Stoppa approach group:preoperative X-ray and CT confirm the diagnosis of anterior pelvic fracture. There are 36 patients with 47 sides of anterior pelvic ring fracture included in the study, involving 22males(27sides) and 14females(20sides) with an average age of 34.4±10.41 ranging from 21 to 65.23 patients had an car accident, while 9 patients fell on the ground and 4 patients injuried by a weight. According to the Tile classification:4 cases were Tile type A; 32cases were Tile type B. There are 11 bilateral superior pubic ramus fractures and 10 unilateral superior pubic ramus fractures. In addition,10 cases were pelvic fractures alone, and 26 cases were multiple injuries (including fracture of the extremities, brain injury, abdominal visceral injury, chest injury and urethral injury).External fixation group:preoperative X-ray and CT confirm the diagnosis of anterior pelvic fracture. There are 14 patients with 24 sides of anterior pelvic ring fracture included in the study, involving 8males(14sides) and 6females(10sides) with an average age of 30.5±11.51 ranging from 17 to 63.6 patients had an car accident, while 7 patients fell on the ground and 1 patients injuried by a weight. According to the Tile classification:0 cases were Tile type A; 14 cases were Tile type B. There are 10 bilateral superior pubic ramus fractures and 4 unilateral superior pubic ramus fractures. In addition,3 cases were pelvic fractures alone, and 11 cases were multiple injuries (including fracture of the extremities, brain injury, abdominal visceral injury, chest injury and urethral injury).2. MethodsModified Stoppa approach group:the patients were treated based on the strategy of damage control, and surgery could be performed until the patient was stable. All the patients operate 3 to 12 days (the mean days was 6.5 days) after pelvic injury. Open reduction and internal fixation were performed through modified Stoppa approach. There are 36 cases with anterior pelvic ring plate fixation.External fixation group:the patients were treated based on the strategy of damage control, and surgery could be performed until the patient was stable. Surgery was performed under local or general anesthesia with the patients on supine position. Superior and rotation displacement of anterior pelvic fracture was corrected by distraction and manual reduction. A 2.5 to 3 cm incision was made from anterior superior iliac spine to medial inferior direction, and then carefully dissected the sartorius muscle to expose the posterior inferior iliac spine and avoid injury of the lateral femoral cutaneous nerve. The angle between drill and sagittal plane was approximately 30°～45°, directing to posterior inferior iliac spine, with 5～6 cm depth, and then a 6 mm diameter Schantz pin was placed. Another Schantz pin was placed at the same level with a distance of 1 cm between pins and 5 cm outside the skin. The contralateral Schantz pins were placed through the above method. The standard Schantz pins were then connected to appropriate length radio lucent bars by combination clamps and then the bars connected by tube-to-tube clamps over the pubis assuring at least 2-finger breaths of clearance above the soft tissues. The connection between the bars should not tight until confirmation of satisfied reduction by C-arm.2. Postoperative managementModified Stoppa approach:prophylactic antibiotic was used to management infection. Based on the stability and quality, rehabilitation was applied on the bed in the early (3-5days) postoperatively, and limited weight-bearing should be performed 6-8weeks postoperatively, and full weight-bearing can be performed 10～12 weeks postoperatively.External fixation group:prophylactic antibiotic was used to prevent infection. Radiography of pelvic was performed to evaluate and adjust the position of fracture 24～48 hours after reduction and fixation of anterior pelvic fracture. Patients can be allowed to full weight-bearing 8 weeks postoperatively.4. Methods of scoringThe quality of reduction was evaluated by the Matta score. If the maximal distance of bone fragment less than 4mm, the quality of reduction was excellent. If between 5 to 10 mm, it was good. If between 11 to 20 mm, it was medium. If the maximal distance of bone fragment is larger than 20mm, the quality of reduction was poor. Clinical rehabilitation was evaluated by Majeed score standard. Excellent>85points; good:70-84 points; medium:55-59 points; poor:< 55points.5. Statistical AnalysisThe data of length of the incision, intraoperative time, blood lose were recorded as the intraoperative criteria, as well as the Matta score and Majeed score standard.Results:Modified Stoppa approach group:1、the mean length of incision was 8.62±1.74 cm (8-12 cm) and the average operation time was 48.13±7.80min (40-78min); the mean blood loss was 55.61±17.60 mL (40-95mL) respectively.2、According to Matta standard, all cases obtained excellent reduction.36 patients were followed up from 8 to 24 months with an average of 18 months, and 4 lost. The healing time of fracture was from 3 to 5.5 months with an average of 3.8 months. There was no reports of nonunion, delayed union, malunion, infection or heterotopic ossification. The average Majeed score was 84.42±6.80 (62～95), and the excellent and good rates can account to 95.0%.3、One patient had external iliac vessels injury, which was fixed during the surgery. After plate removal, another patient’s wound was nonunion. Debridement and bacterial culture were performed before closing the incision, and the wound healed 2 weeks later with negative culture.External fixation group:1、the mean length of incision was 5.64±0.50 cm (single side 2.5～3 cm) and the average operation time was 43.5±6.02min (35～60min); the mean blood loss was 28.93±8.36 mL (20～50 mL) respectively.2、4 patients were followed up from 6 to 18 months with an average of 14.5 months. According to Matta standard,14 cases with 24 sides obtained excellent reduction. The healing time of fracture was from 4.0 to 7.5 months with an average of 5.8 months. There was no reports of nonunion, delayed union, malunion during the follow-up, but 3 patients sustained pins infection.3、After removing the pins, debridement and bacterial culture were performed before closing the incision in patients who had pins infection, and the wound healed 1～2 weeks later with negative culture.Conclusions:The modified Stoppa approach can be used to treat pubic ramus fractures, pubic symphysis injuries and some acetabular fracture. Compared with ilioinguinal approach and Pfannenstiel approach, modified Stoppa approach also has the advantages of small incision, easy for visualization and reduction, low rates of complication rate and rapid rehabilitation.According to the study, there was no significant difference in operation time between patients who underwent modified Stoppa approach those underwent external fixation, and incision and blood loss is poorer in modified Stoppa approach group, but the modified Stoppa approach group had better Matta score and Majeed score, which represents the quality of reduction and clinical rehabilitation, respectively. In addition, modified Stoppa approach can avoid pins infection and easily change to supine position for posterior ring fixation. Therefore, it is recommended to treat pelvic fractures through modified Stoppa approach. Moreover, for the emergency treatment pelvic fractures, external fixation may be replaced by the modified Stoppa approach.