INTERNAL FIXATION FOR UNSTABLE PELVIC FRACTURE: THE VALUE OF ANTERIOR APPROACH AND SMALL FRAGMENTS BIOSYNTHESIS

Fifty patients with unstable pelvic fracture were subjected to internal fixation through anterior approach by small fragment biosynthesis over sixteen year of experience. Their age, range between 15–45 years. Forty patients were males and ten patient females. Thirty patients with type B rotationally unstable fracture pelvis, 15 patients with type C vertically unstable and 5 patients with combined rotationally and vertically unstable fracture. In type B fracture, 30 patients were surgically approached anteriorly by pfennenstiel incision, while type C (15) patients required ilioinguinal extension to fix anterior and posterior ring. Combined unstable fracture in 5 patients require anterior and posterior approach as two stages surgical exposure with one week interval. It is concluded that anterior approach to displaced pelvic fracture was good and suitable for young and thin patients. In addition anterior ring fixation was the key for anatomical reduction of displaced fracture and horizontal application of small fragment implant across the sacroiliac joint and anterior ring could be achieved and maintain the stability if full weight bearing is delayed to 6 month. Other advantages and limitation of the procedure were discussed. Introduction pen reduction and internal fixation of displaced pelvic fracture has become more accepted as clinical experience and certain technologies had improved, and it is considered the most stable form of stabilization 1-5 . The superiority of internal fixation over external fixation was supported by several biomechanical evaluation 6,7 . Therefore internal fixation becomes more popular and in the last three decades introduced by AO group using specialized reconstructed plate and screws or a designed rod for SI joint fixation 8 . The method was supported by other studies from other trauma centers in the world, but still the surgical approach to posterior pelvic ring whether anterior or posterior remains a subject of controversy 1-5,7 . The objective of this study is to stress the advantages of anterior approach for fixation of unstable fracture pelvis with small fragment biosynthesis over the posterior approach and over all methods of internal fixation. Material and Methods Between January 1994 and January 2011, fifty patients with unstable pelvic fracture admitted to Basrah orthopedic center were selected for internal fixation through anterior approach to fix pelvic ring. Type B (rotationally unstable) (30 patients), type C (vertically unstable), and simple combined pelvic fracture were included in this study. Complex fracture pelvis including ace tabular fracture were excluded (Table I). Forty patients were males and 10 patients females, theirs age ranged between 15–45 O Internal fixation for unstable pelvic fracture Madhat Mohammed Mahdi Bas J Surg, September, 17, 2011 59 years (Table II). Forty five patients had body weight 70 kg. and below while remaining five have body weight more than 90 kg. All patients received intensive primary life support measures to survive acute trauma. Plain radiography of the pelvis was routinely done and CT scan in selected cases (i.e. in the earlier period of the study CT was non available). Five patients had associated injuries such as fracture humerus 1, fracture femur 2, and intra-abdominal injury 2. They all had preliminary heavy skeletal tibial or femoral traction. They were operated upon within two weeks except in two patients. One of them was a female who refuses operation initially to accept fixation after 4 weeks, the second one needed to manage associated injuries. The attendance of general surgeon was required in five cases for meticulous inguinal canal repair and to deal with urologic problems. The operative procedure was performed under general anesthesia in supine position. The skeletal traction was continued through the whole procedure to help and maintain the reduction. The incision was pfennenstiel suprapubic approach to pubic symphysis or through inguinal canal in case of rami fracture. Fixation was accomplished by using small fragment plate and screws. The posterior ring (SI) joint was approached by posterior half of ilioinguinal incision through retroperitoneal retroiliacus reflection. Double horizontal parallel small fragment plate and screws were fixed across SI joint. In five patients (type C) who required posterior approach were operated one week later as second stage procedure. Intraoperative radiography was limited to minimum operative time and total hospital stay was estimated and the patients were nursed in bed. Stitches removed after two weeks and the patients were allowed to be nursed in a mobile chair until 12 weeks. Supervised weight bearing using pair of axillary crutches after 12 wks to total period of follow up ranged between 12 wks to 36 months. Results Supine position during operation was comfortable to the patient and easy for anesthetist to control and deal with any complication. In addition the surgeon was able to reduce and fix most pelvic fractures in presence of continuous skeletal traction and with help of lateral compression by assistant under direct vision reducing the demand for intraoperative radiographic control. Posterior ring fixation is required for 15 patients with type C (vertically unstable) through ilioinguinal approach following anterior ring fixation, because of insufficient stability in vertically unstable fractures. Anterior ring fixation alone was sufficient to achieve stability in rotationally (type B) unstable fractures, this indicates anterior ring fixation was the key point in treatment of unstable pelvic fracture in general. In five patients with combined instability (rotational and vertical) sacroiliac joint fixation was difficult because of relative obesity a reason behind a second stage operation to fix the SI joint through posterior approach in prone position 7 days later. Single vertical three holes small fragment plate was used for fixation. Satisfactory anatomical reduction could not be achieved in one patient (female) who accept the operation 4 wks later and in whom the anterior ring disruption (displaced pubic rami fracture) was ignored. Entrapment of injuried urinary bladder within separated pubic symphysis was found in one patient. It was initially missed at a time of notified negative laparotomy. The operative time required ranged between 90 to 120 minutes. Superficial wound infection encountered Internal fixation for unstable pelvic fracture Madhat Mohammed Mahdi Bas J Surg, September, 17, 2011 60 in one patient and superficial sacral sore in another one. Both responded to local care, nursing, and antibiotic. One patient died on the third postoperative day because of pulmonary embolism his operation was performed late (after 3 wks), and he had associated fracture around the elbow joint treated initially by internal fixation and laparotomy to correct colonic injury. Partial implant failure was reported in one patient after three months following fixation of posterior ring by posterior approach in obese patient (body weight more than 90 kg), because of early weight bearing and engagement in sport (football). Fortunately it passes without complication and it did not required removal of biosynthesis. The anterior ring was stable and the patient still active for the last two years. Other patients were committed to post operative rehabilitation and returned to their usual activity gradually without disability. Leg length inequality (3cm) was encountered in one patient (female) who developed gradually increasing gluteal and back pain because of imbalance during walking, this indicates in situ fixation of displaced fracture did not reduce post operative disability because of uneven distribution of stress on anatomical and displaced sides during moderate and high physical activity. Neither incisional nor inguinal hernias were reported during the period of follow up. Total hospital stay was 3 to 6 weeks. Table III summarized result. Discussion This study can verify the indications, advantages and disadvantages of anterior internal fixation for unstable pelvic fracture excluding the complex type. The procedure can be performed at the time of emergent laparotomy or delayed for few days to allow evaluation and treatment of life threatening injuries, preoperative planning and assembly of necessary equipment. In reports from large trauma center patient with pelvic fracture were susceptible to pulmonary failure and septic state described by Seibel et al has led some authors to consider early open reduction and internal fixation of disrupted pelvic ring 9 . In this study one patient died as a result of pulmonary embolism because he was operated upon very late (more than 3 wks) to stabilize unstable pelvic fracture. The author recommended early stabilization of unstable pelvic fracture (within 2 wks) in order to prevent thrombo-embolism and to achieve perfect anatomical reduction since malalignment encountered in one patient (a female) who accepts surgery after 4 weeks. The last observation was supported by Russel and Depaolo in their series using the technique recommended by simpson et al 10 . Matta and Tornetta emphasized the importance of early reduction and fixation of unstable pelvic fracture within 21 days was excellent compared to delayed operation 11 . We agreed with other reports from trauma center that coordination between radiologist, trauma and orthopedic surgeon was important in reduction of mortality and since urologic injuries could be identified and dealt with at the same time 12 . Controversy still existing over the ideal anterior pelvic implant especially with significant posterior pelvic instabilities that stresses the anterior fixation. Tornetta Dickson and Matta advocated the use of single 3.5mm reconstruction plate for symphyseal diastasis 13 . Webb et al reported good results in their series with use of two holes dynamic compression (DCP with 6.5 mm screws directed dow