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Closed Reduction and Percutaneous Iliosacral Screw Fixation of Sacroiliac Injuries: Surgical Technique and Outcome

 Osama Farouk*

* Department of Orthopaedic Surgery and Traumatology, Faculty of Medicine, Assiut University , Assiut , Egypt

Address for Correspondence:  

Ass. Prof. Osama Farouk
Orthopaedic Department, Assiut University Hospitals, Assiut 71516, Egypt
Phone:  +20 882356741 Mobile: +20 122443531
Fax    :  +20 882333327


Internal fixation has become standard treatment in unstable sacroiliac injuries. Associated soft tissue trauma increases risk of complications when attempting open reduction and internal fixation. Closed reduction and percutaneous screw fixation seems to minimize this risk. Thirty-six vertically unstable pelvic fractures were included in a prospective clinical study. Closed reduction and percutaneous iliosacral screw fixation was done in all patients. The mean age of patients was 31 years (range 15 to 60 years). The posterior injury was pure sacroiliac dislocation in seventeen patients, sacroiliac fracture dislocation in seven and sacral fracture in twelve. The anterior lesion was pure symphyseal disruption in twelve patients, ipsilateral fracture of superior and inferior pubic rami in fifteen, bilateral fracture of pubic rami in two, and combined fracture of pubic rami and symphyseal disruption in seven. Two pelvic fractures were open. Perineal tear was associated in two patients. Anterior fixation was by symphyseal plating in nine patients and by external fixation in two. Twenty five had no anterior fixation. Closed reduction was excellent in twenty two patients, good in ten, and fair in four. Loss of reduction was reported in three patients during follow up. Screw misplacement occurred in four patients but without neurological or vascular complications. Pain free gait was achieved in 54% of patients, occasional pain in 35% and persistent pain in 11%.  We conclude that closed reduction and iliosacral screw fixation allows anatomical restoration of stability of sacroiliac disruptions in the vertically unstable pelvis.

J.Orthopaedics 2007;4(4)e26

Pelvic bone fracture; iliosacral screw; closed reduction; sacral fracture; sacroiliac injury


Vertically unstable fractures of the pelvis are uncommon, but it is well established that extensive disruption of the pelvis is associated with high rates of mortality and late morbidity (1, 2). According to Tile’s classification (3, 4) the characteristic of completely unstable pelvic ring injury is complete disruption of the posterior sacroiliac complex associated with an anterior pelvic ring injury. The posterior lesion may be a displaced fracture of the sacrum or ilium, a dislocation through the sacroiliac joint, or a combination of fracture and dislocation injuries. This lesion renders the pelvis unstable in all planes. Vertical instability refers to disruption of the anterior and posterior pelvic ring allowing potential displacement posteriorly, superiorly, and in the sagittal plane rotation (flexion), in addition to rotation in the horizontal plane (internal or external rotation).

In recent years efforts have been made to improve the results by a more interventional approach. There is now increased interest in the use of internal fixation of the posterior disruption (5, 6). There are a variety of methods available, including iliosacral screws, sacral bars, and anterior and posterior plating techniques. The benefits of fixation remain to be clearly established and the optimal methods of fixation, particularly for sacroiliac dislocations and sacral fractures, are still a source of controversy. Iliosacral screw fixation has been popularized by Routt (7, 8). These screws may be used for both sacroiliac joint dislocations and sacral fractures and can be placed percutaneously if a satisfactory closed reduction can be obtained.

The aim of this study was to evaluate the effectiveness of closed reduction and percutaneous iliosacral screw fixation in sacroiliac injuries and to assess the functional outcome of these patients.

Material and Methods :

Patient population: Thirty-six pelvic fractures were included in this study. All patients were treated in the author's institution, a level I trauma center, over a five-year period from January 2002 to December 2006. There were nineteen males and seventeen females with a mean age of thirty-one years (range 15 to 60 years). Motor vehicle accidents accounted for twenty-four cases. Of the remaining twelve injuries, two were crushing injuries after train accidents and ten were the result of a fall from a height.

Inclusion criteria: According to Tile's classification, (3, 4) thirty six patients with vertically unstable type-C pelvic disruptions (Figure 1) were included in this study, when the posterior lesion was either sacroiliac dislocation (C1.2) or sacral fracture (C1.3). Pelvic fractures with posterior disruption through the iliac bone (C1.1) were excluded.

Pre-operative Assessment: Prior to operative treatment, all patients were evaluated clinically and radiographically with standard anteroposterior, inlet, and outlet views of the pelvis. This was augmented with a computed tomography scan of the pelvis in all patients.

Fracture classifications: The posterior injury was pure sacroiliac dislocation in seventeen patients, sacroiliac fracture dislocation in seven and sacral fracture in twelve. According to the classification proposed by Denis et al. (9), there were seven Zone I trans-alar sacral fractures and five Zone II trans-foraminal fractures. The anterior lesion was pure symphyseal disruption in twelve patients, ipsilateral fracture of superior and inferior pubic rami in fifteen patients, bilateral fracture of pubic rami in two patients, and combined fracture of pubic rami and symphyseal disruption in seven patients. Two of the pelvic fractures were open. Perineal tear was associated in two patients.

Neurological assessment: Six patients (17%) had a preoperative sacral nerve root or lumbosacral plexus lesion. All were reported in patients with sacral fractures. Thus, the incidence of nerve injury was (50%) in this group of twelve patients with sacral fractures. In four patients the lesion consisted of pain in an S1 to S3 distribution and impairment of sensation with no significant motor loss. In one patient there was motor weakness of plantar flexion and knee flexion. The final patient had a complete lumbosacral plexus injury of the injured side.

Associated injuries: In thirteen patients the pelvis was the only injury; the remaining twenty three patients had multiple injuries. The median injury severity score was 25 (range 16 to 54). Four of these patients had a laparotomy to deal with intraperitoneal sources of blood loss before definitive orthopaedic fixation. One of them was associated with traumatic intrauterine foetal death that needed hysterotomy. Six patients had urological injuries in the form of ruptured bladder in two patients and urethral injury in four. Two patients suffered chest injuries with multiple rib fractures and pulmonary contusion. Ten patients had associated skeletal injuries in the form of long bone fractures in six, crushed hand in one, contralateral pelvic ring fracture in two and ipsilateral acetabular fracture in one. Head injury was reported in one patient.

Time of surgery: Fixation of the pelvic fracture was performed within the first week after injury in all patients.

Surgical technique: Closed reduction and percutaneous iliosacral screw fixation of the posterior element of the injury was performed with the patient positioned prone on the radiolucent operating table. Single C-arm fluoroscopic guidance for check of reduction and placement of cannulated screws was used in all patients. The operative procedure included the following steps:

1. Closed reduction of the fracture: Under fluoroscopy control in alternating anteroposterior, inlet and outlet projections to correct the three dimensional displacement of the hemipelvis. It included 3 steps: 1) Longitudinal traction to correct the vertical migration, 2) Forward push of the hemiplevis to correct the posterior displacement, and 3) Internal or external rotation to correct external or internal rotation of the hemipelvis.

2. Insertion of guide wires: Location of the starting point was first done under fluoroscopic guidance targeting S1 segment, followed by insertion of the guide wires under sequential anteroposterior, inlet, and outlet fluoroscopic views to pass perpendicular to the sacroiliac joint following S1 mass into the body of S1 (Figure 2). The sequential fluoroscopic guidance in the three views is mandatory during insertion of guide wires to avoid mal-placement and surgical risks such as neurological or vascular injury. The anatomical landmarks or S1 boundaries should be identified under fluoroscopy. These are S1 foramen inferiorly and L5-S1 intervertebral disc superiorly that are best identified in outlet view. Neural canal posteriorly and anterior cortex of S1 segment anteriorly are best viewed in the inlet projection.

3. Insertion of screws: Cannulated 7mm lag screws are inserted after drilling over the guide wires under fluoroscopy to check the final screw position and length (Figure 3).

A total of eighty-two screws were used. Two screws were used in twenty-six cases, and three screws in the remaining ten cases.

Fixation of the anterior lesion:  In all cases the anterior lesion was usually addressed first. The patients can be sorted into three groups according to fixation of the anterior lesion.

Figure 1. shows disruption of the pelvic ring in vertically unstable Tile's type-C fracture pelvis.

Figure 2. shows insertion of guide wires under fluoroscopic guidance perpendicular to the sacroiliac joint into S1 body

Figure 3. shows final check of position and length of inserted iliosacral lag screws.

Group A: Internal fixation group

Anterior plate fixation was done in cases with pure symphyseal disruption. Anterior plating was done before iliosacral screw fixation because this facilitates closed reduction of the posterior lesion. It was performed through a Pfannenstiel incision, using narrow four-hole DCP plates. Internal fixation with plating was done in nine cases. Single plate fixation was used in seven patients and double plates in two (Figure 4 A-C).

Preoperative Radiograph

CT scan of the posterior pelvis which reveals sacroiliac disruption bilaterally

Postoperative radiograph showing anatomic restoration of the pelvic ring with anterior symphyseal plate fixation and posterior percutaneous iliosacral lag screws.

Group B: External fixation group

In the present series, external fixation was used in two cases, one with open pelvic fracture and extensive soft tissue injury, and the second had disruption of the contralateral pelvic ring through pubic rami anteriorly and the iliac bone posteriorly. The general condition of the patient did not allow extensive surgery using an extended ilioinguinal approach to fix the anterior lesion bilaterally. In the two cases where external fixation was used, the iliosacral screws were placed first because the external fixation frame makes patient's positioning and imaging of the sacroiliac region more difficult. The external fixation consisted of a simple anterior trapezoidal frame taking purchase from the strong supra-acetabular bone by introducing the pins through the anterior inferior iliac spine.

Group C: No fixation group

Twenty five patients had no fixation of the anterior lesion, as the anterior lesion consisted of minimally displaced pubic rami fractures after reduction and fixation of the posterior lesion in twenty four patients, and a minimally displaced symphyseal disruption with a leaking supra-pubic tube preventing anterior fixation in one patient.

Postoperative care: Patients were allowed to mobilize and start weight-bearing on the unaffected side with touch weight-bearing on the affected side. Patients with bilateral lesions were kept non-weight-bearing for a period of at least six weeks. External fixators were removed six weeks post-injury. Initial data regarding clinical results and complications were recorded for all patients. Reduction was graded according to the method of Tornetta and Matta (10) (excellent: </= 4 mm of residual displacement; good: 4-10 mm; fair: 10-20 mm; poor: > 20 mm).

Follow-up: After discharge, the patients were reviewed clinically and radiologically. These patients were asked to report persistent pelvic pain. Clinically a neurological assessment was made of lower limb motor and sensory function. Any apparent leg length discrepancy was measured. Inlet-outlet and anteroposterior pelvic views were taken.  Reductions with residual displacement in excess of one centimeter in any plane were taken to represent a malunion.

Results :

The mean period of follow-up was twenty one months (range 6 to 48 months). One multiply injured patient died during follow up.

Reduction of the posterior injury: According to Tornetta and Matta reduction was excellent in twenty-two patients (61%), good in ten (28%) and fair in four (11%) at the initial operative procedure. The posterior lesion in the four patients with fair reduction was two sacroiliac dislocations, one fracture dislocation sacroiliac joint and one Denis type-II fracture sacrum. The anterior lesion in these patients was associated symphyseal disruption and pubic rami fractures in two, pure symphyseal disruption in one and pubic rami fracture in one.

Re-displacement of the posterior injury: Over the course of the following two months, a gradual loss of reduction was noted in three patients (8%), two with sacral fractures and one with sacroiliac joint dislocation.

Therefore, radiographs following fracture union showed malunion (more than one centimeter displacement) in seven patients (19%). All patients of malunion group were treated without anterior internal fixation. In one patient, external fixator was used anteriorly and the deformity recurred while the frame was still in situ. The other six patients were left without any anterior fixation. None of patients in whom the anterior lesion was plated sustained a malunion.

Malunion was noted in three out of twelve (25%) sacral fractures, three out of seventeen (18%) sacroiliac dislocations, and one of seven (14%) fracture dislocations of the sacroiliac joint. The extent of final malunion varied from 1.5 to 2.5 centimeters (mean 1.8 centimeters).

Screw placement: Screw misplacement occurred in four patients (11%). Three patients had screws violating the anterior cortex and protruding through the anterior aspect of the sacrum. One patient had a screw with protruded threads into S1 foramen. This was not detected during fluoroscopic placement and was only apparent on postoperative radiographs. No new neurological or vascular injuries were observed in spite of these errors.

Infection: Infection occurred once after percutaneous iliosacral screw fixation in an immune compromised multiply injured patient with intra-peritoneal haemorrhage and traumatic intrauterine foetal death. Pin tract infection of external fixator pins complicated the two cases where frames were used. Infection subsided after hardware removal.

Functional outcome: The functional outcome of one patient, who died during follow up, was excluded from the results. All other patients regained full weight bearing during follow up. Time to full weight bearing varied according to associated other skeletal injuries with average 12 weeks. The patient with associated complete lumbosacral plexus injury became brace user.

Four patients reported erectile dysfunction that remained till last follow up.

Nineteen (54%) patients regained pain free gait. Twelve (35%) patients reported occasional pain that did not affect the patient's daily activity. Four (11%) patients reported persistent pain. The first patient was multiply injured patient who had associated sacral roots injury with ipsilateral fracture acetabulum and contralateral pelvic ring disruption. The second had associated ipsilateral complete lumbosacral plexus injury. The third was a female patient who had open fracture of the pelvis with extensive perineal tear and severe soft tissue injury that needed several surgeries for repair and reconstruction of her soft tissue trauma. The last patient had persistent pain that was explained by an associated spondylolysis of the fifth lumbar vertebra.

Discussion :

Unstable pelvic injuries have been associated with high rates of morbidity and mortality (11).  There has been increasing interest in the role of internal fixation in the management of these injuries (12). A number of reports have suggested that mortality and long-term functional results can be improved by a more interventional operative protocol (13, 14). In many cases the anterior fracture can be stabilized by plating, which is the method of choice in cases where it is technically feasible. The selection of fixation method for the posterior lesion is more controversial. Sacral bars have the advantage of simplicity and relative safety. They are also versatile and can be used for sacroiliac joint dislocations, for sacral fractures, and in patients with bilateral posterior lesions. However, judging the quality of the reduction is difficult and there is a risk of over-compression with nerve injury when a sacral fracture is present. In addition, the ends of the bars are often prominent and a source of discomfort to the patient (15). More direct methods of reduction and fixation include techniques of anterior and posterior plating. Anterior plate fixation of a sacroiliac dislocation is a useful technique. Simultaneous exposure of the anterior lesion is possible and the quality of reduction is therefore easier to assess. However, access to the sacral side is limited and injury to the L5 nerve root is a definite risk. Anterior plating is not feasible for sacral fractures because the medial access is too limited. Posterior approaches have been advocated, particularly for sacral fractures. Pohlemann et al. (2) have shown biomechanically that local osteosynthesis with specially designed plates is comparable to the fixation achieved with sacral bars. Mears et al. (1) have suggested the use of a double cobra plate to deal with complex bilateral posterior lesions. Iliosacral screw fixation is a well-recognized technique for treating the posterior lesion (7). Iliosacral screws may be used for both sacral fractures and sacroiliac joint dislocations. Fixation has most commonly been carried out using an open posterior approach. Some authors have noted a high complication rate in association with posterior pelvic wounds. The major disadvantage of the posterior approach is the risk of impaired wound healing and subsequent infection with a combined incidence reported as high as 25% in one series (15). More recently the use of percutaneous placement has been described (7). This method has particular advantages in the multiply traumatized patient and in patients with hemodynamic instability where it is desired to minimize blood loss (7). However, an adequate closed reduction must be obtained prior to screw placement.

Closed reduction and percutaneous fixation

Routt et al. (8) reported on the use of percutaneous iliosacral screws in sixty-eight pelvic fractures, of which forty-three were Type C injuries. Closed reduction of the posterior lesion was possible in fifty-one cases. Mal-reduction occurred in twelve (18%) and failure of fixation in a further three cases.

In this study, excellent and good reduction of fracture was achieved in 89%. Loss of reduction occurred in three patients (8%).  The overall malunion rate was 19%.

Screw misplacement

Some concern has been expressed about the safety of the technique, and with screw misplacement there are undoubtedly significant risks to the cauda equina and the L5 and S1 nerve roots in particular. The need for high-quality fluoroscopic imaging and technical expertise has been emphasized if the technique is to be used safely (7, 8). Bony anatomical variations are common in this region, and the importance of the lateral view of the sacrum to show the alar slope is now well recognized (3).

The potential for screw misplacement is demonstrated in the present study. Fortunately, the degree of error was small, only in four occasions (11%), and no vascular or neurological complications occurred.

Functional outcome

As might be expected, the functional outcome following these severe injuries may be poor in a high percentage of patients. Late pain in the region of the sacroiliac joint is a well-recognized problem, even in cases where the reduction is satisfactory (6).

In the present series many patients had pain at the time of follow-up but it was severe in only four patients (11%). These four patients have associated injuries or other reasons that account for this persistent pain.

The present series includes a comparatively large number of vertically unstable injuries. When they are subdivided with respect to the posterior and anterior lesions, this makes firm conclusions difficult to draw. It seems clear, however, that these injuries have a marked tendency to re-displace. It is a trend that was most notable in fractures where no anterior fixation was applied. In retrospect, anterior plate fixation would have been advisable in these cases. The use of external fixation may reduce the malunion rate, but the lowest rate was found in patients with plate fixation of the anterior pelvis. Although the numbers studied were not large enough to achieve statistical significance, the trend suggests that more rigid anterior fixation yields superior anatomical results.


We believe that early stabilization of the vertically unstable pelvis is valuable in terms of reducing morbidity and improving long-term functional outcome. Closed reduction and percutaneous iliosacral screws are very useful for dealing with the posterior lesion with minimum morbidity. However, our results suggest that for optimum anatomic results, rigid internal fixation of the anterior lesion is required.

Reference :

1. Mears DC, Capita CP, Deleeuw H. Posterior pelvic disruptions managed by the use of the double cobra plate. AAOS Instruct Course Lect 1988; 37: 143-150.

2. Pohlemann T, Angst M, Schneider E, Ganz R, Tscherne H. Fixation of transforaminal sacrum fractures: a biomechanical study. J Orthop Trauma 1993; 7: 107-117.

3. Tile M. Classification. In: Tile M, ed. Fractures of the Pelvis and Acetabulum. Media, PA: Williams & Wilkins, 1995. p. 66–101.

4. Tile M. Acute pelvic fractures: I. causation and classification. J Am Acad Orthop Surg. 1996; 4: 143–151.

5. Leighton R, Waddell J. Open reduction and internal fixation of vertical fractures of the pelvis using the sacroiliac joint plate. J Orthop Trauma 1991; 5: 255-258.

6. Matta JM, Saucedo T. Internal fixation of pelvic ring fractures. Clin Orthop 1989; 242: 83-97.

7. Routt ML Jr, Meir MC, Kregor PK, Mayo KM. Percutaneous iliosacral screws with the patient supine technique. Operat Tech Orthop 1993; 3: 35-45.

8. Routt MLC, Kregor PJ, Simonian PT, Mayo KA. Early results of percutaneous iliosacral screws placed with the patient in the supine position. J Orthop Trauma 1995; 9: 207-214.

9. Denis F, Davis S, Comfort T. Sacral fractures: an important problem. Retrospective analysis of 236 cases. Clin Orthop 1988; 227: 67-81.

10. Tornetta III P, Matta JM: Long term follow-up of operatively treated unstable posterior pelvic ring disruptions. Orthop Trans 1995; 19: 161.

11. McMurtry R, Walton D, Dickinson D, et al. Pelvic disruption in the polytraumatised patient: a management protocol. Clin Orthop 1980; 151: 22-30.

12. Burgess AR, Eastridge BJ, Young JWR, et al. Pelvic ring disruptions: effective classification system and treatment protocols. J Trauma 1990; 30: 848-856.

13. Gruen GS, Leit ME, Gruen RJ, Peitzman AB. The acute management of haemodynamically unstable multiple trauma patients with pelvic ring fractures. J Trauma 1994; 36: 706-711.

14. Leenen LPH, van der Werken C, Schoots F, Goris RJA. Internal fixation of open unstable pelvic fractures. J Trauma 1993; 35: 220-225.

15. Kellam JF, McMurtry RY, Paley D, Tile M. The unstable pelvic fracture. Operative treatment. Orthop Clin North Am 1987; 18: 25-41.


This is a peer reviewed paper 

Please cite as :Osama Farouk : Closed Reduction and Percutaneous Iliosacral Screw Fixation of Sacroiliac Injuries: Surgical Technique and Outcome

J.Orthopaedics 2007;4(4)e26





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