INFIX/EXFIX: Innovation managing pelvic fractures in difficult scenarios.

Pelvic fractures complicated by the presence of visceral injuries, open fractures and urethral or bladder injuries pose a significant challenge to treat. In these conditions internal fixation is usually contraindicated. External fixators, though a potential solution, have disadvantages like loss of reduction, pin tract infection and loosening. INFIX, a novel technique has been effective in managing anterior ring fractures and can be used as a substitute for internal fixation. We describe use of INFIX as EXFIX in three case scenarios where passing INFIX rod internally was precluded with favorable outcomes.

Introduction

Management of anterior pelvic ring fractures becomes challenging in presence of visceral injuries, bladder and bowel content contamination. Approximately 15% of urethral and bladder injuries have been associated with anterior ring disruption.[12] Management options for anterior pelvic fixation include ORIF, external fixator application and recently INFIX. However, presence of infection obviates the use of internal fixation.

INFIX is biomechanically stronger than an external fixator.[3] Passing connecting rod of INFIX subcutaneously is contraindicated with suprapubic catheter or infected wound in suprapubic area. We describe its use as EXFIX in three case scenarios of pelvic fractures. Informed written consent was taken.

Case Histories

Case 1

47-year-old male sustained trauma in road traffic accident primarily managed at other hospital for urethral injury with suprapubic catheterization and a pelvic binder, referred to our centre for further management. On examination pelvic compression test was positive. The plain radiographs and commuted tomography (CT) showed vertically unstable pelvic injury on left side type 3 A (Tile classification) with bilateral superior and inferior pubic rami fractures and Zone 2 left sacral fracture [Figure 1a and b]. In prone position posterior stabilization was done using iliosacral screw between S1 and S2 crossing both sacroiliac joints. Using left paramidline incision in lower lumbar region, left L5 and Ilium (Spinopelvic fixation) were stabilized with pedicle screw and rod construct. Following this patient was turned supine and INFIX as EXFIX was applied. Pin tracts were healthy with good position of implants on radiographs at subsequent visits [Figure 1c and d].

Figure 1

(a and b) Radio imaging showing Type 3A pelvic and Zone 2 sacral fracture; (c and d) post-operative radiograph and clinical picture showing suprapubic catheter in place with INFIX rod placed outside; (e and f) follow up radiographs at 4 months and 27 months showing good alignment

Four months postoperatively, planned removal of EXFIX was done after confirming fracture healing on radiographs. He is living normal life and mobilized without difficulty with Majeed pelvis score 74 (Excellent) at latest follow up of 27 months[4] [Figure 1e and f].

Case 2

16-year-old male sustaining fall from 24 feet height resuscitated and managed with suprapubic catheterization for complete urethral rupture and diversion sigmoid loop colostomy for blunt abdomen injury. The plain radiographs and CT showed right type 3 A pelvic injury with right zone 2 sacral fracture with normal neurology, left inferior pubic rami fracture and pubic diastasis [Figure 2a and b]. In prone position right spinopelvic fixation was done followed by INFIX as EXFIX application in supine position [Figure 2c and d].

Figure 2

(a and b) Radio imaging showing pubic diastasis and Zone 2 sacral fracture; (c and d) post-operative radiograph and clinical picture showing suprapubic catheter and colostomy in place with INFIX and spino pelvic fixation; (e and f) follow up radiographs at 4 months and 18 months showing good healing

Four weeks postoperatively planned colostomy closure and urethroplasty was done with EXFIX in place. Four months postoperatively, planned removal of EXFIX was done after confirming fracture healing on radiographs. Patient was mobilized with stick with Majeed score of 40(Fair) at latest follow up of 18 months [Figure 2e and f].

Case 3

45-year-old diabetic male was brought to our emergency department by ambulance after sustaining trauma during collision of automobiles. On examination there were no signs of urethral injury, Pelvic compression test was positive. The radiological assessment showed pubic diastasis of three cm, left sacroiliac joint disruption with left superior pubic rami fracture Type 3 B [Figure 3a] and other associated fractures like closed fracture of proximal phalynx of right index finger and trans trapezoid, trans trapezium axial dislocation of right wrist. In supine position, through transverse incision (Pfannenstiel incision) symphysis pubis was approached, and stabilized with 3.5 mm plate and screw construct. In prone position and under c-arm guidance two left sacroiliac screw are passed. Stability was confirmed under c-arm with no intraoperative complications [Figure 3b]. Other fractures in hand and around wrist were managed using k-wires. Patient was discharged on seventh day after confirming healthy suture line.

Figure 3

(a) Radiograph showing pubic diastasis and left sacroiliac disruption; (b) post-operative radiograph with internal fixation; (c and d) radiograph and clinical picture at 4 months showing healed supra pubic wound and INFIX/EXFIX; (e and f) follow up radiographs at 12 months and 25 months showing good healing

Four weeks post operatively patient presented with purulent discharge from suprapubic incision site, which was managed imperatively with debridement and resuturing, intra operatively no loosening of implant was noted hence retained but to neutralize the forces INFIX as EXFIX was applied [Figure 3c and d]. Appropriate antibiotics given based on culture and sensitivity two weeks intravenous and four weeks oral. Patient was reviewed after six weeks showing complete healing with a healthy scar and pin tracks. Follow up radiographs showed good position of implant. Planned removal of EXFIX done after four months. Patient walking comfortably at latest follow up of 25 months with Majeed pelvis score 65 (Good) [Figure 3e, f and Table 1].

Table 1

Summary of cases

Cases	Injury	Scenario	Intervention	Majeed Score
1) 47 years/M RTA*	Left type 3A fracture with left zone 2 sacral fracture	Suprapubic catheter	Sacroiliac screw and spinopelvic fixation INFIX/EXFIX application	74 (Excellent)
2) 16 years/M FFH†	Right type 3A fracture with right zone 2 sacral fracture	Suprapubic catheter, Diversion colostomy	Sacroiliac screw and spinopelvic fixation INFIX/EXFIX application	40 (Fair)
3) 45 years/M RTA*	Left type 3B fracture with left sacroiliac joint disruption	Early infection of suprapubic wound	Sacroiliac screw fixation with suprapubic plating and INFIX/EXFIX application	65 (Good)

*RTA: Road traffic accident, †FFH: Fall from height

Discussion

Management of Pelvic fractures becomes challenging when surgical field has been contaminated by bowel or bladder content due to visceral injuries, intraabdominal surgical procedures been conducted, or suprapubic catheters are present within the field of potential surgery. In these scenarios external fixators are preferred with limitations, of being cumbersome, pin site infection (2–50%), osteomyelitis in (0–7%) and leading to loss of reduction.[56]

Internal fixators originally described by Kuttner et al. in German literature in 2009.[78] Vaidya et al. modified it and introduced the nickname INFIX.[9] Two small incisions bilaterally taken over the anterior inferior iliac spine. Dissection carried between the interval of Sartorius and tensor fasciae latae muscles. Pedicle screw inserted into supraacetabular region in a corridor of dense bone between the inner and outer tables of the Ilium and directed towards posterior inferior iliac spine. A curved metal rod is passed subcutaneously and connected to the heads of the pedicle screws.[8] If screw heads are kept outside the skin and rod placed externally, it is labeled as INFIX/EXFIX.

Infix can be used as an INFIX and as a partial INFIX partial EXFIX (INFIX/EXFIX) as it is biomechanically stronger than an external fixator due to its low profile.[3] It has revealed improved patient comfort and mobility, reduced pin tract infections, and serving temporary/definitive fixation following posterior stabilization.[7910] Biomechanical studies also have shown that the minimally invasive INFIX has superior stability to external fixation, due to the shorter lever arm of the construct.[7]

In our first two cases patient already had suprapubic catheter in place which negated INFIX rod subcutaneously. Rahul et al. usually advocates putting suprapubic catheter at a little higher than usual position in turn allowing use of INFIX as shown in his study.[11] But if suprapubic catheter is at usual position like in our case, INFIX can be used as EXFIX.

Our third case had suprapubic early infection following internal fixation. In this scenario INFIX/EXFIX gave additional stability till wound heals and helped retaining implant. A retrospective review of 4 cases by Rahul Vaidya has described the use of INFIX as EXFIX in massive open pelvic injuries.[12] Likewise INFIX as EXFIX in our case has shown good outcomes.

None of our patients had pin tract infections or irritation of lateral femoral cutaneous nerve.

Conclusion

INFIX has been proven both clinically and radiologically as an alternative for managing anterior ring pelvic fractures. Though INFIX/EXFIX is in a way similar to external fixator but has advantages of thicker supraacetabular screws adding biomechanical stability and much comfortable to patients helping early mobilization.

Declaration of patient consent

The authors certify that appropriate patient consents were obtained.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.