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Case report| Volume 33, 101991, October 2022

Minimally invasive transiliac anatomical locking plate for posterior pelvic ring injury: A technical trick of the gull wing plate

Open AccessPublished:August 19, 2022DOI:https://doi.org/10.1016/j.jcot.2022.101991

      Abstract

      Posterior pelvic ring injuries commonly involve sacral fractures, which are difficult to reduce and stabilize. Because conservative treatment requires long-term bedrest and leads to unsatisfactory outcomes, surgical intervention is a beneficial option to protect neurological structures and provide sufficient stability for early mobilization. Several studies have investigated a variety of internal fixation techniques, such as iliosacral screws, transiliac bars, spinal instruments, and transiliac plates. The gull wing plate (GWP) is a pre-contoured anatomical locking plate with two cancellous screws (φ6.5 mm) and four locking screws (φ5.0 mm), the design of which is unique among posterior tension-band plates. The GWP provides reliable stability of the posterior construct of the pelvic ring and accelerates rehabilitation. Compared to alternative surgical techniques for posterior fixation, the simple surgical procedure of the GWP is minimally invasive and highly reproducible, which leads to fewer complications and less radiation exposure.

      Keywords

      1. Introduction

      Unstable pelvic ring fractures (type B & C) are uncommon injuries that occur in young adults and elderly patients.
      • Tonetti J.
      • Jouffroy P.
      • Dujardin F.
      Reconstruction of pelvic ring and acetabular fractures: what lies ahead?.
      Posterior ring injuries are commonly caused by sacral fractures, which are difficult to reduce and stabilize. Because conservative treatment requires long-term bedrest and leads to unsatisfactory outcomes, operative intervention is the best option to protect neurological structures and provide sufficient stability for early mobilization. Based on fracture type, displacement, osteoporosis, and operative invasion, we select one of several internal fixation techniques, such as iliosacral screws, transiliac bars, spinal instruments, or transiliac plates.
      • Halawi M.J.
      Pelvic ring injuries: surgical management and long-term outcomes.
      • Decker S.
      • Herden J.
      • Krettek C.
      • Muller C.W.
      A new minimally invasive U-shaped lumbopelvic stabilization technique.
      • Krappinger D.
      • Larndorfer R.
      • Struve P.
      • Rosenberger R.
      • Arora R.
      • Blauth M.
      Minimally invasive transiliac plate osteosynthesis for type C injuries of the pelvic ring: a clinical and radiological follow-up.
      • Suzuki T.
      • Hak D.J.
      • Ziran B.H.
      • et al.
      Outcome and complications of posterior transiliac plating for vertically unstable sacral fractures.
      After posterior transiliac tension-band plates were first introduced by Albert et al., in 1993, several modified techniques have been advocated with satisfactory clinical outcomes.
      • Albert M.J.
      • Miller M.E.
      • MacNaughton M.
      • Hutton W.C.
      Posterior pelvic fixation using a transiliac 4.5-mm reconstruction plate: a clinical and biomechanical study.
      The gull wing plate (GWP; OMIC Corporation, Shiga, Japan) is a newly designed pre-contoured anatomical locking plate with two cancellous screws (φ6.5 mm) and four locking screws (φ5.0 mm), and is widely accepted and utilized as posterior transiliac plates in Japan (Fig. 1). To date, no study has reported on posterior tension-band plates with similar design. The purpose of the present technical note is to describe the surgical procedures of the GWP, its benefits and pitfalls, and brief case reports.
      Fig. 1
      Fig. 1Characteristics of the gull wing plate
      The GWP is a pre-contoured anatomical locking plate, the design of which takes account of the angle and length of the bilateral ilium and spinal process of S1. Two longer cancellous screws (φ6.5 mm) toward the AIIS and four tri-cortical locking screws (φ5.0 mm) penetrating the iliosacral joint can be inserted. (a) Posterior side, (b) cranial side, Scale bars: 30 mm.

      2. Surgical technique

      In cases that require fixation of an unstable anterior component, plate or screw fixation for the acetabular or superior ramus is performed before the prone position. In the prone position, the level of the spinal process of the first sacral vertebra (S1) is marked under an image intensifier. With reference to the marking line, an approximately 5 cm longitudinal incision is designed on the skin 2 cm lateral to the bilateral posterior superior iliac spine (PSIS) (Fig. 2a). When laminectomy is necessary, the skin incision is designed medial to the PSIS, however, which makes it difficult to insert the locking sleeves afterwards. After dissecting the subcutaneous tissue layer, the common fascia at the top of the PSIS is incised. The paravertebral muscle (PVM) at the medial side and the gluteus maximus at the lateral side are periosteally avulsed from the PSIS. Bilaterally, a 15 mm × 15 mm bone groove is created with a bone saw or osteotome. The PVM is avulsed from the posterior surface of the S1. Resection of the spinal process of the S1 is performed by an osteotome from both sides, to create a tunnel connecting the bilateral incision. The spinal process of the S1 should be resected from the tip multiple times to make small pieces. If it is resected from the base at one time and large fragments are produced, this will interfere with the plate insertion through the tunnel. Plate size is determined by plate trial based on plate width and position of the iliac screw hole. Before plate insertion, minced autologous bone (resected PSIS for the bone groove) can be grafted at the posterior surface of the sacral fracture site, if necessary. The selected plate is inserted beneath the PVM and rotated 180 deg to fit into the bone groove (Fig. 2b–d). One of the most important points during surgery is the rotation of the GWP. Great care should be taken to ensure that the wing of the plate is positioned toward the anterior direction. If the wing of the plate is set toward the caudal direction, the iliac screws and locking IS screws could interfere with each other. Bilateral cancellous bone screws (φ6.5 mm) are inserted from the plate hole as far as possible in the direction of the anterior inferior iliac supine (AIIS) (Fig. 2e and f). Since OMIC only makes screws up to 60 mm in length, for cases requiring screws over 65 mm in length, use DePuy Synthes (West Chester, PA, USA) screws (as recommended by OMIC). Bilateral screws are alternately tightened to avoid the seesaw phenomenon. Locking screw sleeves are inserted at the plate holes, and tri-cortical drilling (lateral iliac, medial iliac, and lateral sacral) is performed (Fig. 2g and h). Before measuring the length of the locking screws, the blunt tip of the Kirchner wire is inserted through the locking sleeves to confirm the inside of the sacral bone (Fig. 2i). Next, the locking screw of selected length is inserted with the torque lenti driver. The incised common fascia is repaired to completely cover the plate and reduce postoperative tenderness (Fig. 2l). The postoperative rehabilitation protocol was as follows: all patients were mobilized under physiotherapeutic supervision with half weight bearing (1–13 POD) and full weight bearing (14 POD-) as tolerated.
      Fig. 2
      Fig. 2Surgical procedure
      (a) By palpation, the midline (longitudinal dotted line) and bilateral PSIS (U shape) are marked in a prone position. Under an image intensifier, the level of the spinal process of the first sacral vertebra (transverse line) is marked. With reference to the marking line, a bilateral 5 cm longitudinal incision (X shape) is made on the skin 2 cm lateral of the PSIS.(b) The selected GWP is inserted beneath the PVM. (c,d) The plate is rotated 180 deg from cranial side to fit into the bone groove.(e) Drilling for the iliac cancellous screw is performed toward the AIIS. In this case, a percutaneous retrograde superior ramus screw was inserted in the supine position prior to moving into the prone position.(f) While inserting the iliac screw (φ 6.5 mm), the plate should be held in the anterior direction. A caudal direction plate position would interfere with the iliac screw and the subsequent locking screw.(g) A locking sleeve can be inserted from the same incision. If this is difficult, a stab incision for the locking sleeve is added more laterally to the first incision. (h,i) Tri-cortical drilling (lateral iliac, medial iliac, and lateral sacral) is performed, and the blunt tip of the Kirchner wire is inserted through the locking sleeves to check the inside of the sacral bone and to avoid extra-osseous deviation. (j,k) One cancellous screw (φ 6.5 mm) and two locking screws (φ 5.0 mm) are inserted through the GWP from one incision.(l) Incised common fascia should be repaired completely to cover the plate and reduce postoperative tenderness.(m) Closing a bilateral longitudinal incision (approximately 5 cm).

      3. Case examples

      3.1 Case 1

      A 29-year-old male was involved in a motorcycle accident (Fig. 3). The patient had a pelvic ring injury (AO/OTA 61B3), bilateral sacral fracture (Denis zone II), and bilateral superior and inferior pubic rami fracture. He had associated L5/S1 nerve root injury (Gibbons grade III), L4/5 spinal process fracture, and urinary tract injury. He was initially managed with transcatheter arterial embolization (TAE) and an iliac crest pelvic external fixator. Internal fixation with a gull wing plate was performed on post-accident day 10. The operation time was 113 min, with an intraoperative blood loss of 390 ml. The patient had an excellent pelvic outcome (Majeed score: 87 points) as the insulted nerve root showed complete recovery (Gibbons grade I) at 14 months follow-up.
      Fig. 3
      Fig. 3Case 1
      (a) Plain AP radiograph at the emergency room(b) 3D reconstruction of the CT scan (AP view)(c) 3D reconstruction of the CT scan (inlet view)(d) Postoperative radiograph (AP view)(e) Postoperative radiograph (inlet view)(f) Axial slice of the postoperative CT scan(g) 3D reconstruction of the postoperative CT scan from the left side(h) Plain AP radiograph at 14 months follow-up.

      3.2 Case 2

      A 58-year-old male was involved in a motorcycle accident (Fig. 4). He sustained a pelvic ring injury (AO/OTA 61B1.2); pubic symphysial separation of >25 mm, and subluxation of the left sacroiliac joint, without any neurological deficits. He had a left tibial plateau fracture and a right ankle open fracture/dislocation. He was initially managed with TAE and an iliac crest pelvic external fixator. Open reduction and internal fixation was performed on post-accident day 6. First, anterior plating for the pubic symphysis was performed in the supine position. Next, posterior fixation was performed with the GWP in the prone position. The operation time for the GWP was 106 min. The patient had a good pelvic outcome (Majeed score: 72 points) at 12 months follow-up.
      Fig. 4
      Fig. 4Case 2
      (a) Plain AP radiograph at the emergency room(b) Axial slice of the CT scan after the pelvic external fixator(c) 3D reconstruction of the CT scan (inlet view) after the pelvic external fixator(d) Postoperative radiograph (AP view)(e) Postoperative radiograph (inlet view)(f) Axial slice of the postoperative CT scan(g) 3D reconstruction of the postoperative CT scan (AP view)(h) 3D reconstruction of the postoperative CT scan (inlet view).

      3.3 Case 3

      An 80-year-old male was involved in a bicycle accident (Fig. 5). He had a pelvic ring injury (AO/OTA 61B2.1); left sacral fracture (Denis zone II), and left superior and inferior pubic rami fracture, without any neurological deficits. He had a left ankle open fracture/dislocation. Open chest cardiac massage for traumatic cardio pulmonary arrest due to hemorrhagic shock was performed. He was initially managed with TAE and an iliac crest pelvic external fixator. Open reduction and internal fixation was performed on post-accident day 4. First, using a percutaneous approach, a retrograde superior ramus screw was inserted with the patient in the supine position. Next, posterior fixation was performed with the GWP in the prone position. The total operation time for the superior ramus screw and the GWP was 116 min, with an intraoperative blood loss of 300 ml. The patient had a good pelvic outcome (Majeed score: 56 points) at 8 months follow-up.
      Fig. 5
      Fig. 5Case 3
      (a) Plain AP radiograph at the emergency room(b) Axial slice of the CT scan(c) 3D reconstruction of the CT scan (AP view)(d) Fluoroscopic image (AP view) after the pelvic external fixator(e) Postoperative radiograph (AP view)(f) Plain radiograph (inlet view) at 21 days follow-up(g) Plain radiograph (outlet view) at 21 days follow-up(h) 3D reconstruction of the postoperative CT scan from the posterior side.

      4. Discussion

      Management of pelvic ring injury continues to represent significant challenges for surgeons.
      • Halawi M.J.
      Pelvic ring injuries: emergency assessment and management.
      ,
      • Parry J.A.
      • Funk A.
      • Heare A.
      • et al.
      An international survey of pelvic trauma surgeons on the management of pelvic ring injuries.
      Owing to the recoil capacity of the pelvic ring, x-ray or computed tomography scan might not reflect the potential displacement or instability of the injured pelvic ring.
      • Grewal I.S.
      • Mir H.R.
      Assessment of instability in type B pelvicring fractures.
      ,
      • Parry J.A.
      • Salameh M.
      • Maher M.H.
      • Stacey S.C.
      • Mauffrey C.
      The lateral stress radiograph identifies occult instability of lateral compression pelvic ring injuries without sedation.
      Compared to the anterior structure, the posterior part is more important for hemorrhage control and load transmission from the lower limbs to the spine. The sacrum is often fractured because of its thin cortex, causing neurological deficits constantly.
      Ideal fixation for pelvic ring fracture should provide sufficient stability for early mobilization. Among several fixation techniques, the percutaneous iliosacral screw or trans-iliac screw is minimally invasive and became accepted as the first choice in most cases during the last few decades. Nevertheless, these screws require expert experience, a radiolucent table, a high-quality fluoroscopic machine, and radiation exposure. In addition, dysmorphic sacra do not always allow a corridor for the percutaneous screw at S1. A previous study reported the relatively high rate of screw malpositioning, which leads directly to neurovascular injury. Therefore, a recent study recommended intraoperative computed tomography scan or a navigation system to improve screw position accuracy.
      • Zwingmann J.
      • Hauschild O.
      • Bode G.
      • Sudkamp N.P.
      • Schmal H.
      Malposition and revision rates of different imaging modalities for percutaneous iliosacral screw xation following pelvic fractures: a systematic review and meta-analysis.
      Biomechanical stability of the pelvic ring and postoperative screw loosening were also factors of concern related to percutaneous screw fixation.
      • Berber O.
      • Amis A.A.
      • Day A.C.
      Biomechanical testing of a concept of posterior pelvic reconstruction in rotationally and vertically unstable fractures.
      Recently, several studies have re-evaluated and verified the effectiveness and safety of posterior transiliac plates.
      • Ayoub M.A.
      • Gad H.M.
      • Seleem O.A.
      Standalone percutaneous transiliac plating of vertically unstable sacral fractures: outcomes, complications, and recommendations.
      • Khaleel V.M.
      • Pushpasekaran N.
      • Prabhu N.
      • Pandiyan A.
      • Koshy G.M.
      Posterior tension band plate osteosynthesis for unstable sacral fractures: a preliminary study.
      • Boudissa M.
      • Saad M.
      • Kerschbaumer G.
      • Ruatti S.
      • Tonetti J.
      Posterior transiliac plating in vertically unstable sacral fracture.
      Even among them, locking compression plates appear to have replaced conventional non-locking plates.
      • Schmerwitz I.U.
      • Jungebluth P.
      • Lehmann W.
      • Hockertz T.J.
      Minimally invasive posterior locked compression plate osteosynthesis shows excellent results in elderly patients with fragility fractures of the pelvis.
      The GWP is the modified upgrade version of the M-shaped pelvic plate by Shirahama et al.
      • Shirahama M.
      Surgical treatment of vertically unstable sacral fractures using a new plate.
      The concept of the GWP is to sandwich and bridge the sacrum between the bilateral ilium without direct exposure of the sacral fracture. This plate is inserted beneath the PVM through bilateral longitudinal 5 cm incisions, which have only minimal invasion to soft tissue. Compared to the open method, the shorter operation time and reduced blood loss is assumed to reduce the postoperative infection rate. The pre-contoured anatomical design is beneficial because bending of the thick straight plates during surgery takes time and reduces the plate strength. With regard to the plate design, the angle of the wings takes into account the outer surface of the bilateral ilium, and a wave-like form is also gentle on the PSIS, PVM and the S1 spinal process. Two longer cancellous screws (φ6.5 mm) toward the AIIS and four tri-cortical locking screws (φ5.0 mm) fixing the iliosacral joint provide three-dimensional fixation, and solidify the posterior structure of the pelvic ring. The achieved rigidity provides sufficient stability to allow early mobilization, weightbearing, and activities of daily living. There are only two contraindications for the GWP. The first is fracture type, such as significantly displaced fractures (especially in the cranial/caudal direction) and bilateral severe injuries around the sacroiliac joints. The second is severely damaged soft tissue, such as a Morel–Lavallée lesion. The only shortcoming of the GWP is that it requires the prone position, which is regarded as more disadvantageous for reduction than the supine position. However, if necessary, a Schanz screw from the PSIS can be used to achieve adequate reduction.
      • Martin M.P.
      • Rojas D.
      • Mauffrey C.
      Reduction and temporary stabilization of Tile C pelvic ring injuries using a posteriorly based external xation system.
      The GWP represents a simple and safe procedure with fewer complications and less radiation exposure than percutaneous screw fixation. This operation can be done with standard fracture treatment equipment at any institution, without the need for the specialized skills. Optional procedures such as laminectomy or autologous bone grafting can be easily added. The wing of the plate should be positioned toward the anterior direction to avoid interference between the cancellous iliac screws and locking IS screws. Large size-6 screws achieve three-dimensional fixation of the posterior pelvic construct and reliable stability accelerate postoperative rehabilitation. Further study is necessary to investigate the long-term outcomes and compare them to those of alternative surgical techniques.

      Author contributions

      SMi conceived the research, performed data collection, and wrote the manuscript. SMi and KK performed the operation. SMa gave final approval of the manuscript.

      Funding

      No funding.

      Informed consent

      Appropriate consent was obtained from all individual participants included in the study.

      Declaration of competing interest

      The authors have no conflicts of interest to disclose.

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