Minimally-invasive fixation for anterior pelvic ring disruptions

A new technique for percutaneous screw fixation for treating FFP IIIa and IIIb fragility fractures of the pelvis

To determine the presence of a consistent osseous corridor from the lateral-posterior aspect of the anterior inferior iliac spine to the sacral wing that could be used for safe trans percutaneous screw fixation for pelvic fragility fractures of the iliac wing and fracture dislocations of the sacroiliac joint (FFP types IIIa and IIIb). Computed tomography (CT) scans were obtained from 100 patients and imported to Mimics software for 3D reconstruction. Then, a cylinder was drawn to imitate the modified LC-II screw and adjusted to a maximum radius and length to obtain the feasible region. Thirteen parameters of the osseous corridor of the modified LC-II screw were measured. Differences between sex groups were compared, and significant statistical correlations were carefully studied to determine potentially important clinical relationships. The records of patients with FFP type IIIa and IIIb fragility fractures of the pelvis were extracted from our hospital. Patients who underwent modified LC-II screw fixation, LC-II screw fixation or reconstruction plate fixation were included. Patients' operative characteristics and complications were recorded at follow-up. Fracture reduction quality was assessed using the Matta standard. Functional outcomes were evaluated using the Majeed grading system. The mean maximum diameters of the osseous corridors of the modified LC-II screw in males and females were 12.73 and 10.83 mm, respectively. The mean maximum lengths of the osseous corridors of the modified LC-II screw in males and females were 96.37 and 93.37 mm, respectively. In the treatment of patients with FFP IIIa and FFP IIIb fractures, the group of treatment by the modified LC-II screws fixation was shown significantly shorter operative time and fewer intraoperative blood loss in comparison to that by the reconstruction plates. In the present study, all the males and females had a complete osseous corridor of the modified LC-II screw. The clinical results of the patients who were treated with modified LC-II screw fixation suggest that the novel method has a good preliminary outcome.

Clinical study of modified INFIX combined with sacroiliac joint screws for pelvic instable injuries

OBJECTIVE

The INFIX technique is becoming one of the most commonly performed surgical procedures for anterior pelvic ring instability injuries. The purpose of this article is to compare the clinical outcomes of modified anterior subcutaneous internal fixation (M-INFIX) with conventional anterior subcutaneous internal fixation (C-INFIX) for anterior pelvic ring instability injuries.

PATIENTS AND METHODS

A retrospective analysis of 36 cases of unstable pelvic injuries treated operatively at our institution, 20 of which were treated with C-INFIX and 16 with M-INFIX. Data collected included age, gender, ISS score, fracture typing, operative time, operative bleeding, postoperative complications, fracture healing time, Matta score, Majeed score, and follow-up time. Statistical sub-folding of each variable between the two groups was performed.

RESULTS

There was no statistical difference between the C-INFIX and M-INFIX groups in terms of age, gender, ISS (Injury Severity Score), follow-up time, fracture typing, fracture healing time, and Majeed score (P > 0.05). the M-INFIX had a significantly lower incidence of postoperative complications than the C-INFIX group, especially in the incidence of Lateral femoral cutaneous nerve (LFCN) injury (P < 0.05). In contrast, the M-INFIX group had statistically higher operative time, intraoperative bleeding, and Matta score than the C-INFIX group (P < 0.05).

CONCLUSION

This study was based on a modified application of the surgical experience with C-INFIX and showed better clinical outcomes in terms of complication rates and quality of repositioning than the conventional surgical approach. These findings indicate that further analytical studies of this study would be valuable.

Finite Element Analysis of Channel Screw and Conventional Plate Technique in Tile B2 Pelvic Fracture

Objective: This study aims to analyze the biomechanical characteristics of tile B2 pelvic fractures using finite element analysis when the superior ramus of the pubis was fixed by a plate or hollow screws in standing and sitting positions, respectively. Methods: A three-dimensional digital model of the tile B2 pelvic fracture was obtained by CT scanning the patient. The main ligament structure was then reconstructed based on the anatomical characteristics to create a finite element model of the tile B2 pelvic fracture. The posterior pelvic ring was fixed by sacroiliac joint screws, while the anterior ring injury of the superior ramus of the pubis was fixed by plates and hollow compression screws, respectively. The degrees of freedom of the bilateral acetabulum or two sides of the ischial tuberosity were constrained in the two models. A vertical load of 600 N was applied to the upper surface of the sacrum to measure the displacement and stress distribution of the pelvis in the standing and sitting positions. Results: The displacement distribution of both the healthy and the affected side of the pelvis was relatively uniform in both the plate group and the hollow screw group according to the finite element simulation results. The maximum displacement value in the sitting position was greater than the standing position, and the maximum displacement value of the hollow screw fixation was greater than that of the plate fixation. In the four groups of fixation models, the maximum displacement value of the pelvis in the hollow screw sitting position group was 1616.80 × 10−3 mm, which was greater than that of the other three groups, and in this group the total displacement value of the hollow screw in the anterior ring was 556.31 × 10−3 mm. The stress distribution of the pelvis in the various models was similar in the four groups of models, in which the maximum stress of the pelvis in the hollow screw sitting position group was the largest, which was 201.33 MPa, while the maximum stress in the standing position was 149.85 MPa greater than that in the sitting position of the hollow screw fixation. Conclusion: The anterior ring of patients with Tile B2 pelvic fractures fixed with hollow screws or plates in both standing and sitting positions can achieve satisfactory biomechanical results with significant safety margins for plates and screws.

Novel Covert-Inferior Pelvic Approach with a Subpubic Plate for Anterior Pelvic Ring Fractures: Preliminary Results

BACKGROUND

Anterior pelvic ring injuries can be treated via Pfannenstiel, modified Stoppa, or ilioinguinal approaches, but these require exposing the abdominal soft tissues and may damage pelvic organs. The scar on the abdominal wall is also unacceptable for some patients. The minimally invasive anterior pelvic ring internal fixator (INFIX) is not ideal for thin patients with easily irritated skin, and it is associated with complications such as femoral nerve palsy, vascular occlusion, and lateral femoral cutaneous nerve injury. In this study, we designed a new external pelvic approach for the treatment of an anterior pelvic ring fracture.

METHODS

We retrospectively reviewed 28 patients with 36 pubic ramus fractures that had been treated via the covert-inferior pelvic approach. All patients underwent a surgical procedure between August 2019 and January 2021. According to the Nakatani classification, there were 6 cases of type-I fracture, 25 cases of type-II fracture, and 5 cases of type-III fracture. Operative time, blood loss, and postoperative radiographic and computed tomographic (CT) findings were recorded. Patients were followed for fracture healing time, functional status, esthetic satisfaction, and complications.

RESULTS

A total of 27 patients had follow-up for at least 12 months (range, 12 to 29 months). Postoperative radiographs and CT scans showed well-positioned plates and screws. The mean preoperative time was 9.4 ± 3.8 days, the mean operative time was 61.3 ± 22.67 minutes, the mean intraoperative blood loss was 63.6 ± 42.62 mL, the mean fracture healing time was 4.1 ± 1.6 months, and the mean Majeed score was 89.74 ± 8.07. There were no complications of nonunion, internal fixation failure, vascular injury, nerve palsy, or hernia. All of the patients were esthetically satisfied with the scar.

CONCLUSIONS

The covert-inferior pelvic approach combined with a subpubic plate effectively fixed Nakatani type-I, II, and III fractures. The advantages of this method include rapid recovery after the surgical procedure, safety, simplicity, a short learning curve, no damage to abdominal soft tissue, no effect on pubic symphysis micromotion, and esthetic benefits. It may be another option for anterior pelvic ring fractures and can supplement other approaches.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Identification of safe channels for screws in the anterior pelvic ring fixation system

Background

Minimally invasive surgery for pelvic fracture using anterior ring internal fixator system is increasing gradually, and the way to insert the fixation screws in the fixation system is the key technical points of the method. However, there have been few studies on insertion of fixation screws for the anterior pelvic ring internal fixator system.

Objective

To identify safe channels for fixation screws in the anterior pelvic fixator system and provide the anatomical basis for insertion of fixation screws in clinical operation.

Methods

Screw insertion was simulated into a total of 40 pelvic finite element models as well as 16 fresh pelvic specimens, and the channel parameters were measured.

Results

Finite elements (male, female) include: screws in ilium: length 114.4 ± 4.1 and 107.6 ± 8.3 mm, respectively; diameter 11.7 ± 0.5 and 10.0 ± 0.6 mm, distance between screw and anterior inferior iliac spine: 5.5 ± 1.0 and 5.6 ± 1.0 mm, angle of coronal plane 55.8° ± 2.4° and 50.6° ± 3.1°, angle of sagittal plane 26.6° ± 1.0° and 24.5° ± 1.9° and angle of horizontal plane 64.9 ± 3.7 and 58.1 ± 3.1; screws in pubis: length 47.0 ± 2.0 and 39.8 ± 3.9 mm, diameter 7.1 ± 0.4 and 6.1 ± 0.4 mm. Specimens (male, female) include: distance between screw and anterior inferior iliac spine: 5.5 ± 0.5 and 5.6 ± 0.7 mm, angle of coronal plane 55.9° ± 1.3° and 50.7° ± 1.5°, angle of sagittal plane 26.7° ± 0.5° and 24.1° ± 0.9° and angle of horizontal plane 64.8° ± 0.6° and 58.8° ± 0.8°. In the comparison between female and male in each group, differences in distances between screws and anterior inferior iliac spine and median line of symphysis pubis (P > 0.05) were not statistically significant; differences in the remaining parameters were statistically significant (P < 0.05).

Conclusions

If surgeons paid attention to sex differences, select screws of appropriate diameter and length and hold the insertion position and direction, screws in the anterior pelvic ring fixation system could be safely inserted.

Variability in rod to bone distance needed in pelvic subcutaneous internal fixation to avoid nerve compression: A tridimensional population-based study

INTRODUCTION

Pelvic internal fixation has become a popular method for treatment of unstable pelvic ring injuries. Although successful, one complication is femoral nerve palsy from compression of the connecting rod. In light of this complication, this study was designed to evaluate sagittal inclinations of the rod and the feasibility of using a rod with a constant curvature.

HYPOTHESIS

It is hypothesized that that there is a connection between the sagittal inclination of the rod and the rod to bone distance, as well as single rod can be contoured with a constant curvature to be used in the majority of all patients.

METHODS

Three dimensional models of pelvis CTs from a single level 1 trauma center were created and imported into a program where software superimposed a pre-contoured rod in the sagittal planes upon the pelvic slices. The sagittal inclination was deemed acceptable is no interference occurred between the area of compression risk and the rod. For each pelvis and considered sagittal rod inclination, the rod radius of curvature (ROC), minimal rod to bone distance (RTB) and transverse inclinations (φ_L and φ_R) were measured at which the pedicle screws should be inserted to follow the direction of the smallest RTB.

RESULTS

The sagittal inclinations feasible for all subjects were between 15° to 30°. In this sagittal range, the average RTB varied in values ranging from 4.0±0.9mm to 25.4±11.4mm (p<0.01). Only 46% of subjects allowed a rod with constant curvature.

DISCUSSION AND CONCLUSION

Our study found that a rod to bone distance of 15mm was not safe for all models. As well, many subject models did not allow placement of pre-contoured rod. Patient specific templating of pelvic subcutaneous internal fixation is strictly needed to limit complications.

LEVEL OF EVIDENCE

VII; Basic Science.

Midterm follow-up of elderly patients with fragility fractures of the pelvis: A prospective cohort-study comparing operative and non-operative treatment according to a therapeutic algorithm

INTRODUCTION

The treatment of fragility fractures of the pelvis (FFP) is a challenge. The variations of non-operative- and of operative treatment are manifold and a structured treatment algorithm is lacking. The purpose of this study was to evaluate the outcome of elderly patients with a FFP who were treated with a therapeutic algorithm based on the FFP-classification.

PATIENTS AND METHODS

In a prospective cohort study 154 patients (mean age: 81.8 ±.61 (65-96); female: (86.8%; 131/154). BMI: 23.7 ±.34 (15-43)) with a FFP after inadequate mono trauma were treated according to a strict therapeutic algorithm between 04/2016 and 12/2018. According to a classification based on CT-scans either a standardized operative treatment or conservative therapy was induced and the outcome regarding objective measurements of mobility, pain, need for analgesics and mortality during hospital stay and after one year was analyzed.

RESULTS

82/154 participants (53.2%) were assigned to the conservative treatment group and 72 participants (46.8%) to the operative treatment group. The overall one-year survival rate was 78.1% (118/151). The survival of the operative treatment group was 90.7% (49/54) and significantly higher than the survival of the conservative treatment group (74.7%; 56/75; p=.023). The one-year follow up showed a high dispersion of the pain level in the operatively treated patients and a significantly higher mean in comparison to conservatively treated patients. Both treatment groups showed increasing numbers of patients with unlimited mobilization but also immobile patients. Overall in 31.0% (18/58) of the operative participants and in 14.9% (14/93) of the non-operatively treated participants complications occurred (p=.04).

CONCLUSION

The strict compliance to the presented treatment algorithm of FFP with an operative strategy starting from FFP IIc leads to a significantly lower mortality within one year in comparison to the conservatively treated patients. The worst outcome and the highest mortality was seen in patients who refused the recommendation of operative stabilization. The results of this study justify to proceed with the strict classification dependent treatment algorithm and also support the early switch-over to operative treatment of patients with failed conservative therapy in FFP I to FFP IIb.

Is Anterior Plating Superior to the Bilateral Use of Retrograde Transpubic Screws for Treatment of Straddle Pelvic Ring Fractures? A Biomechanical Investigation

Background: Fractures of the four anterior pubic rami are described as “straddle fractures”. The aim of this study was to compare biomechanical anterior plating (group 1) versus the bilateral use of retrograde transpubic screws (group 2). Methods: A straddle fracture was simulated in 16 artificial pelvises. All specimens were tested under progressively increasing cyclic loading, with monitoring by means of motion tracking. Results: Axial stiffness did not differ significantly between the groups, p = 0.88. Fracture displacement after 1000–4000 cycles was not significantly different between the groups, p ≥ 0.38; however, after 5000 cycles it was significantly less in the retrograde transpubic screw group compared to the anterior plating group, p = 0.04. No significantly different flexural rotations were detected between the groups, p ≥ 0.32. Moreover, no significant differences were detected between the groups with respect to their cycles to failure and failure loads, p = 0.14. Conclusion: The results of this biomechanical study reveal less fracture displacement in the retrograde transpubic screw group after long-term testing with no further significant difference between anterior plating and bilateral use of retrograde transpubic screws. While the open approach using anterior plating allows for better visualization of the fracture site and open reduction, the use of bilateral retrograde transpubic screws, splinting the fracture, presents a minimally invasive and biomechanically stable technique.

Modified pedicle screw-rod versus anterior subcutaneous internal pelvic fixation for unstable anterior pelvic ring fracture: a retrospective study and finite element analysis

Objectives

This study compared the stability and clinical outcomes of modified pedicle screw-rod fixation (MPSRF) and anterior subcutaneous internal pelvic fixation (INFIX) for the treatment of anterior pelvic ring fractures using the Tornetta and Matta grading system and finite element analyses (FEA).

Methods

In a retrospective review of a consecutive patient series, 63 patients with Orthopaedic Trauma Association (OTA)/Arbeitsgemeinschaft für Osteosynthesefragen (AO) type B or C pelvic ring fractures were treated by MPRSF (n = 30) or INFIX (n = 33). The main outcome measures were the Majeed score, incidence of complications, and adverse outcomes, and fixation stability as evaluated by finite element analysis.

Results

Sixty-three patients were included in the study, with an average age of 34.4 and 36.2 in modified group and conventional group, respectively. Two groups did not differ in terms of the injury severity score, OTA classification, cause of injury, and time to pelvic surgery. However, the MPSRF group had a rate of higher satisfactory results according to the Tornetta and Matta grading system than the conventional group (73.33% vs 63.63%) as well as a higher Majeed score (81.5 ± 10.4 vs 76.3 ± 11.2), and these differences were statistically significant at 6 months post-surgery. FEA showed that MPSRF was stiffer and more stable than INFIX and had a lower risk of implant failure.

Conclusions

Both MPSRF and INFIX provide acceptable biomechanical stability for the treatment of unstable anterior pelvic ring fractures. However, MPSRF provides better fixation stability and a lower risk of implant failure, and can thus lead to better clinical outcomes. Therefore, MPSRF should be more widely applied to anterior pelvic ring fractures

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02618-9.

Biomechanical Analysis of Retrograde Superior Ramus Screw Fixation Constructs

OBJECTIVE

To investigate the biomechanical performance of different size and length retrograde superior ramus screws.

MATERIALS AND METHODS

A vertical superior ramus fracture was created in osteoporotic composite hemipelvis bone models (Sawbones, Vashon Island, WA). After reduction, 4 fixation groups were created by inserting either a solid 4.5 mm (Depuy Synthes, Paoli, PA) or cannulated 7.0 mm screw (Zimmer, Warsaw, IN) of either 80 mm (short) or 140 mm (long) in length. An intact and an unstabilized osteotomy group were also created. Samples underwent cyclic loading for 5000 cycles with data acquisition at regular intervals. At the end of cyclic loading, load to failure was performed.

RESULTS

The displacement after 5000 cycles for 4.5 mm short screws was significantly greater than 4.5 mm long and 7.0 mm short screws. At 5000 cycles, the 4.5-mm short screws had a significantly lower stiffness and lower load to failure than all other screws and were not different from the osteotomy model.

CONCLUSIONS

Short 4.5-mm screws demonstrated increased displacement, lower stiffness, and decreased load to failure compared with all other screws. The biomechanical performance of 4.5-mm short screws was no different than unstabilized controls. Longer bicortical screw fixation is suggested when possible. Additional biomechanical and clinical studies are needed to fully understand the significance of these findings.

Clinical research on minimally invasive internal fixation for the treatment of anterior ring injury in tile C pelvic fracture

The aim of this study is to explore the clinical outcome and indications in treating anterior ring injury of Tile C pelvic fracture with minimally invasive internal fixation.We retrospectively reviewed 18 patients (aged 25-62, 34.2 ± 7.4) with 26 pelvic anterior ring injuries of Tile C pelvic fracture treated with minimally invasive internal fixation in our hospital were from January 2012 to August 2016. Two cases were pubic symphysis diastasis, 15 were anterior ring fracture (7 were bilateral), and 1 was vertical displacement of pubic symphysis associated with pubic ramus fracture. According to Tile classification, 8, 4, and 6 cases were types C1, C2, and C3, respectively. All patients accepted the operation of pelvic fractures on both rings, while the anterior ring injuries were treated with minimally invasive internal fixation. The period from injury to operation was 5 to 32 days (11.2 ± 3.7). Four patients had pubic symphysis diastasis or pelvic anterior ring fracture medial obturator foramen reduced with modified Pfannenstiel incision and fixed with cannulated screws, 14 patients (22 fractures) had a fractured lateral obturator foramen reduced with modified Pfannenstiel incision associated with small iliac crest incision and fixed with locking reconstruction plates. Clinical data, such as operation time, intraoperative bleeding, Matta standard to assess the reduction quality of fracture, and complications, were collected and analyzed.The operation time ranged from 30 to 65 minutes (42.8 ± 18.7), and the intraoperative bleeding volume was 30 to 150 mL (66.5 ± 22.8). All cases were continuously followed-up for 16 to 42 months (30.2 ± 4.6). All fractures were healed between 3 and 9 months postoperatively (4.9 ± 2.7 months). According to the Matta standard assessment, 18, 7, and 1 cases were excellent, good, and fair, respectively, with a 96.2% (25/26) rate of satisfaction. Neither reduction loss, fixation failure, nor infection occurred; complications included 1 patient with fatal liquefaction, 1 patient had lateral femoral cutaneous nerve injury, and 1 patient complained of discomfort in the inguinal area due to fixation stimulation.Minimally invasive internal fixation for pelvic anterior ring injury in Tile C pelvic fracture has the advantages of less damage, safer manipulation, less complications, and good prognosis.

A novel internal fixation method for open book injuries of the pubic symphysis- A biomechanical analysis

BACKGROUND

Pelvic fractures in adults are common injuries and account for up to 3.64% of all fractures. Usually, the treatment of open book injuries (Types B1.1 and B1.2 AO-Classification) is open reduction and plate stabilization using dynamic compression plates, with or without interlocking screws. These implants seem to enhance the outcome of such injuries, but also variety of complications occurs. To reduce complications and achieve appropriate reduction and stabilization, this study compared established stabilization techniques to a novel minimally invasive internal fixation method using an internal fixator system that is already being utilized for spinal fractures.

METHODS

This study was performed on 32 composite pelvises in a bilateral stance biomechanical model. The pelvises were variously stabilized with an internal fixator, a 4.5 mm dynamic compression plate and a 3.5 mm symphyseal locking dynamic compression plate. The contact area and loading forces were assessed by a sensor film inside the symphyseal gap.

FINDINGS

This study showed significantly greater reduction and loading capabilities of the internal fixator compared to the other implants (p < 0.05). There was also significantly greater contact area with the use of an internal fixator compared to the other implants (p < 0.05). The 3.5 mm interlocking plate showed significantly greater contact area compared to the 4.5 mm plate (p < 0.05).

INTERPRETATION

The internal fixator that is already proven in spinal surgery is biomechanically superior to conventional implants used in pelvic surgery. The contact area analysis furthermore showed a more physiological loading pattern, which can improve ligamentous healing in a clinical context.

What's New in Percutaneous Pelvis Fracture Surgery?

Percutaneous reduction and fixation of pelvic ring fractures is now widely accepted as a safe and effective treatment method. The only exception remains reduction and fixation of pubic symphyseal injuries. Several units from China and one from Spain have published clinical and biomechanical studies supporting percutaneous reduction and fixation of the pubic symphysis with various screw configurations. The initial clinical results are promising. Biomechanical data show there is little difference between plate and screw fixation. We review the current literature and also present a case performed by ourselves using this novel technique.

Stabilization of a Type B1.1 Injury in a Morbidly Obese Patient Using an Internal Fixator in a Minimally Invasive Technique: A Case Report

CASE

In this case report, we present a novel stabilization technique of the pubic symphysis using an internal spinal fixator in a 78-year-old morbidly obese woman having a pelvic disruption type B1.1 (AO classification). We treated the disruption using an internal fixator to reduce the extent of the incision and soft-tissue damage.

CONCLUSIONS

The use of an internal fixator, known from percutaneous spinal fixation, for the stabilization of the pubic symphysis in cases of disruption ("open book" injuries) may be an alternative to the standard plate fixation as a novel minimally invasive stabilization technique.

A cost minimization analysis comparing minimally-invasive with open reduction surgical techniques for pelvic ring fracture

The aim of the present study was to compare the in-hospital direct medical costs of patients with pelvic fracture treated with minimally invasive surgery (MIS) or open reduction and internal fixation (ORIF). A retrospective, single-center, cohort, and comparative study was performed. Administrative information and clinical results, in addition to cost data, were collected and analyzed. A cost minimization analysis method was used to evaluate the costs of two different surgical techniques. A total of 128 patients diagnosed with pelvic fracture were included in this study; 62 were treated with MIS and 66 underwent ORIF. No significant difference was observed between the 2 groups in terms of patients' clinical baseline characteristics. The operative time, length of incision, intra-operative blood loss, and post-operative length of stay in the MIS group were significantly different compared with those in the ORIF group. The cost-minimization analysis demonstrated that the cost effectiveness of MIS was better than ORIF as the MIS was associated with a significantly lower total in-hospital direct medical cost ($8,900 vs. $5,786, P=0.032), compared with ORIF. The cost-minimization analysis demonstrated that for similar clinical baseline characteristics as well as outcomes, there were differences in direct hospitalization cost of two surgical techniques, and MIS had a lower cost on average than ORIF.

Complications Following Internal Fixator in the Treatment of Pelvic Fracture

The aim of this systematic review was to investigate the incidence of complications of the internal fixator in the treatment of anterior pelvic ring injury. The literature was comprehensively searched from 1980 to January 2017 to identify potential studies. Six studies involving 272 cases of anterior pelvic ring injury treated with the internal fixator were included in this meta-analysis. The rates of wound infection, heterotopic ossification, nerve paresthesia, pain, and fracture dislocation were 5.7%, 35.1%, 28.2%, 3.7%, and 3.0%, respectively. This new technique should be prudently used to treat pelvic fractures. [Orthopedics. 2019; 42(1):e7-e13.].

Minimally Invasive Endoscopic-Assisted Technique for Implant Removal After Pelvic Bridge Plating

Subcutaneous internal plate fixation for anterior pelvic ring injuries has become more common, but implants require removal, usually by 12 weeks. The purpose of this article is to report a novel, minimally invasive, endoscopic-assisted technique for the removal of subcutaneous anterior pelvic plates safely and atraumatically without violating the underlying fascia.

Minimally invasive treatment for anterior pelvic ring injuries with modified pedicle screw-rod fixation: a retrospective study

Background

Pelvic ring injuries constitute only 2 to 8% of all fractures; however, they occur in 20% of polytrauma patients. High-energy pelvic fractures often result in mechanical instability of the pelvic ring. Successful treatment of unstable pelvic ring fractures remains a challenge for orthopedic surgeons. This study presents a novel internal fixation method for stabilizing unstable anterior pelvic ring fractures using a minimally invasive modified pedicle screw-rod fixation (MPSRF) technique.

Methods

This retrospective study included six patients with unstable pelvic ring injuries who underwent MPSRF, with or without posterior fixation. Intraoperative parameters such as blood loss, operative time, complications, and quality of reduction (Matta criteria) were recorded and evaluated by a blinded reviewer.

Results

In the present clinical series, the mean operative times and mean blood loss for unilateral versus bilateral anterior ring fixations were 176.0 min versus 295.6 min, and 153.3 mL versus 550.0 mL, respectively. No iatrogenic neuropraxia of the lateral femoral cutaneous nerve or femoral nerve palsy occurred. The reduction quality, graded by the Matta criteria, was excellent in five patients and good in one patient.

Conclusions

There were no infections, delayed unions, nonunions, or loss of reductions during the follow-up period. Only one patient suffered from a broken rod at 4 months postoperatively. The modified technique represents a novel, minimally invasive procedure for the treatment of anterior pelvic ring fractures and offers a reliable and effective alternative to currently available surgical techniques.

Anterior Pelvic Ring: Introduction to Evaluation and Management

The evaluation and management of pelvic ring injuries continues to evolve. Historic treatment was primarily nonsurgical, which yielded to open surgical treatment as the benefits of restoring pelvic anatomy and stability became clear. The development of percutaneous techniques for pelvic ring fixation enabled surgeons to reduce and stabilize certain injuries without the need for large open surgical dissections. Although percutaneous iliosacral screw fixation of sacral fractures and sacroiliac disruptions is the standard for most posterior pelvic ring injuries, the evaluation and treatment of anterior pelvic ring disruptions remains a controversial topic among surgeons who treat these injuries. Universally accepted indications for anterior pelvic ring stabilization do not exist, and there is little comparative data to support one surgical technique over another. In fact, some believe that for many injuries, the anterior ring rarely requires fixation after stable fixation of the posterior pelvic ring. The purpose of this work is to present a brief history on management of the anterior pelvic ring as a component of pelvic ring disruptions and briefly review the anatomy of the anterior pelvic ring. Finally, we will introduce the current techniques available for anterior pelvic reduction/stabilization and present information on evaluation of anterior ring stability as a means of guiding treatment.

Prospective Study of Closed Reduction of Trochanteric Fractures via a Novel Intraoperative Femoral Fracture Reduction Device: Early Clinical Results

OBJECTIVE

Traction achieved using an intraoperative femoral fracture reduction device (IFFRD) was compared with that observed using a traction table (TT) for closed reduction of trochanteric fractures and cephalomedullary nail fixation.

DESIGN

Prospective cohort study.

SETTING

Level 1 trauma center.

PATIENTS

One hundred forty-one eligible patients with 141 fractures (Orthopaedic Trauma Association type 31-A1, n = 28; A2, n = 75; and A3, n = 38 cases) were randomized to the IFFRD (n = 73) or TT (n = 68) group.

INTERVENTION

The IFFRD was used while the patient was placed on a normal radiolucent operation table with 25-30 degrees elevation of the injured side to allow for antero-posterior and lateral fluoroscopic examination and facilitate entry-point guide wire insertion.

MAIN OUTCOME MEASURES

Patient demographics, operative and fluoroscopy duration, quality of fracture reduction, and radiological bone union time were recorded.

RESULTS

Patient demographics were similar between groups. Duration of patient positioning was longer in the TT group (P < 0.05); duration of fluoroscopy, fracture reduction, and time to union were comparable.

CONCLUSIONS

An IFFRD used with a normal radiolucent operation table decreased patient positioning time, with efficacy comparable to the TT approach for closed reduction of trochanteric fractures.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Treatment of type B pelvic fracture using anterior subcutaneous internal fixator with triple pedicle screws: a new surgical technique

INTRODUCTION

To evaluate the clinical outcomes of anterior subcutaneous internal fixator using triple pedicle screws (ASIF/TPS) in the treatment of unstable type B pelvic fracture compared with open reduction internal fixation (ORIF).

MATERIALS AND METHODS

This was a retrospective cohort study of 26 patients with type B unstable fractures that underwent ASIF/TPS and 26 similar patients that underwent ORIF using plates and screws. Intraoperative blood loss, operating time, and post operation hospitalization duration were compared. Anteroposterior, inlet, and outlet X-rays and 3D computed tomography were obtained. Pain, numbness, sexual dysfunction, and activity were evaluated at every follow-up visit until the implants were removed. The Majeed score was used to assess the clinical and radiological outcomes.

RESULTS

Blood loss, operating time, and hospitalization duration were less (all P < 0.001) in the ASIF/TPS group compared with the ORIF group. The clinical and radiological outcomes of the ASIF/TPS group after a mean follow-up of 6 months were excellent and good in 80.8%, and moderate in 19.2%. In comparison, the results of the ORIF group were excellent and good in 65.4%, moderate in 29.0%, and poor in 5.6%. No patient experienced nonunion, delayed union, superficial infection, or deep surgical wound infection. No urethral injury or dysuria occurred in the ASIF/TPS group. Two patients had temporary lateral femoral cutaneous nerve numbness after operation. There were two superficial wound infections in the ORIF group.

CONCLUSIONS

The use of ASIF/TPS with triple pedicle screws could be a reasonable option for the treatment of type B unstable pelvic fractures.

Numerical Investigation on the Biomechanical Performance of Laparoscopic-Assisted Plate Used for Fixing Pelvic Anterior Ring Fracture

Because of the minimal soft tissue injury, the laparoscopic-assisted internal fixation is a promising technique in fixing the pelvic anterior ring fracture. The aim of this study was to investigate the biomechanical performance of the laparoscopic-assisted plate by the finite element method. Four kinds of implants were investigated, that is, the laparoscopic-assisted plate (LAP), the percutaneous anterior pelvic bridge (PAPB), the transramus intraosseous screw (TIS), and the open reduction (OR). The stability of the implants was investigated under three loading cases, showing that when the LAP was used, the stress at the fracture site was smaller than that at other parts, while for other implants, the high stress was always around the fracture site. In conclusion, the LAP demonstrated a good biomechanical performance in fixing the pelvic anterior ring fracture and is a promising technique in clinical applications.

[Management of complex acetabulum fractures and their consequences]

In the structure of pelvic bone injuries, acetabular fractures are the most complex type and, according to different authors, account for up to 20% [1]. The severity of these injuries is confirmed by the fact that early descriptions of acetabular fracture were based only on the results of autopsies of patients who had suffered a combined injury. Thus, as early as 1788, Callisen reported an acetabular fracture, but without a detailed description of the nature of the injury. In 1909, Schroeder provided a detailed report of 49 cases of acetabular fractures reported in the literature. Most of them were described during autopsies of patients who died from complications associated with hemorrhagic shock or the onset of sepsis [2]. Fractures of the acetabulum in most observations are the result of high-energy impacts, usually as a result of traffic accidents; therefore, the mechanism of injury determines the combined and multiple nature of the injuries in the victims. A significant proportion of acetabular fractures (up to 60%) are accompanied by fragment displacement and dislocation of the femoral head, in which the most severe tissue changes occur [3].

Midterm radiologic and functional outcomes of minimally-invasive fixation of unstable pelvic fractures using anterior internal fixator(INFIX) and percutaneous iliosacral screws

BACKGROUND

Anterior pelvic external fixation is associated with pin site infections, aseptic loosening with loss of reduction, frame bulkiness hindering patient mobilization and consequent difficulties in inpatient nursing. We performed a single-center prospective series to evaluate the feasibility, safety, limitations and midterm radiologic and functional outcomes of an alternative minimally invasive pelvic internal fixation technique using an anterior subcutaneous pelvic internal fixator (INFIX) and percutaneous iliosacral screws in unstable pelvic ring fractures.

METHODS

Fifteen consecutive patients with vertically and/or rotationally unstable pelvic fractures, presenting to a Level-1 trauma center were treated with closed reduction, appropriate posterior stabilization with percutaneous iliosacral screws and anterior INFIX application. Outcomes were analyzed with respect to the quality of fracture reduction (Matta's radiologic criteria), ease of inpatient nursing, patient mobility and comfort, functional outcomes at final follow-up (Majeed score, SF-12 score), social reintegration and complications.

RESULTS

Most common injury pattern was AO/OTA type 61-C pelvic fracture in thirteen patients. Mean procedure time and intra-operative blood loss were, 57.1+/-4.9 min (range,51-68 min) and 115.3+/-26.7 ml (range,80-170 ml) respectively. Mean follow-up was 34.9+/-4.1 months (range,31-42 months). Fracture reduction was excellent in twelve and good in three patients (Matta's criteria). Functional outcomes were excellent in eight and good in seven patients (Majeed score). Mean SF-12 scores for physical and mental health were 48.58+/-5.61 and 50.89+/-3.97 respectively. Thirteen patients returned to their pre-injury jobs. All fifteen patients reintegrated into society without any restrictions. INFIX was removed at a mean post-operative period of 7.3+/-1.5 months (range,5.5-11 months). Complications included, lateral femoral cutaneous nerve irritation(n = 1), superficial wound infection(n = 1) and loss of reduction(n = 2).

CONCLUSION

Minimally invasive pelvic stabilization using INFIX and percutaneous iliosacral screws is easy to learn and apply, achieves good fracture reduction and definitive stabilization with minimum complications and offers excellent functional outcomes at a minimum follow-up of 31 months.

LEVEL OF EVIDENCE

Level IV.

"Anterior subcutaneous pelvic internal fixator (INFIX), Is it safe?" A cadaveric study

INTRODUCTION

Anterior pelvic internal fixator (INFIX) is used to treat unstable pelvic ring injuries. Nerve injury complications with this procedure have been reported.

OBJECTIVES

This anatomic study attempted to identify structures at risk after application of INFIX.

MATERIALS AND METHODS

INFIX was applied in fifteen fresh, frozen, anatomical specimens using polyaxial pedicular screws and subcutaneous rods. Surgical dissection was done to identify the structures at risk including the femoral nerve (FN), femoral artery (FA), femoral vein (FV) and the lateral femoral cutaneous nerve (LFCN) related to which are potentially affected by the implant.

RESULTS

All structures at risk were closer to the rod than to the pedicular screw. Measurements were made between the rod and the structures at risk. The LFCN was an average of 13.49±1.65mm (95% CI 12.871-14.103) from the lateral end of the rod. The FN was an average of 12.43±3.42mm (95% CI 11.151-13.709), the FA was an average of 12.80±3.67 (95% CI 11.430-14.173) and the FV was an average of 13.48±3.73 (95% CI 12.082-14.871) below the rod. No direct compression of the rod to the structure at risk was observed.

CONCLUSIONS

The femoral nerve is the structure most at risk of compression by the INFIX rod. Careful surgical technique is required in every step of this surgery. We suggest using polyaxial screws and recommend that during screw insertion the surgeon should leave some space between the screw and rectus fascia. The the rod should be trimmed as short as possible to reduce LFCN irritation.

Is cannulated-screw fixation an alternative to plate osteosynthesis in open book fractures? A biomechanical analysis

OBJECTIVES

The current biomechanical work compares the symphyseal and sacroiliac stability obtained with two systems of bone osteosynthesis. The two methods of fixation compared were the 6-hole suprapubic non-locked plate and pubic fixation with two cannulated screws, a novel technique that can be applied percutaneously in the clinical practice. The aim of this study was to examine the validity of the use of two-cannulated-screws osteosynthesis in order to minimize the secondary effects of open fixation, especially in patients in whom an open reduction is contraindicated.

MATERIALS AND METHODS

A biomechanical study was designed in 9 fresh, human pelvis specimens, simulating an AO B1.1 type injury, using both fixation systems sequentially in each specimen. In both parts of the test, the specimens were subjected to an axial load of 300N. Displacements and rotations between the different pelvic elements were studied by means of a discrete set of points. The absence of differences between the two systems has been set as the null hypothesis.

RESULTS

There were significant differences in favor of the cross-cannulated screws in most of the displacements measured at the pubic symphysis and sacroiliac joint.

CONCLUSIONS

Fixation of the AO B1.1 type fractures with cross cannulated screws restores the biomechanical behavior of the pubic symphysis, obtaining better stability than fixation with the 6-hole non-locked plate. To date, no comparative, biomechanical studies have been conducted with these two systems of osteosynthesis. This study demonstrates that cross-cannulated screws fixation of the pubic symphysis in AO B1.1 pelvic fractures should be considered as an alternative to the conventional plating system.