Achievable pin spanning angulation in anterosuperior pelvic external fixation

European Journal of Orthopaedic Surgery & Traumatology - Pelvic external fixation using anterosuperior pins provides a quick method of stabilization without necessitating fluoroscopic guidance....     

三种外固定置钉方法治疗骨盆骨折

[目的]通过回顾性分析,对比骨盆骨折后使用3种不同外固定支架置钉方法间的并发症发生率,为临床置钉提供理论依据。[方法]选择2006年1月~2016年5月两医院骨盆骨折患者232例,Tile A型119例,Tile B型55例,Tile C型58例,随机分为髂嵴上置钉组,髋臼上置钉组和髂嵴下置钉组进行治疗并随访18个月,对比平均手术时间、平均出血量、术后功能恢复情况、神经损伤、钉道感染率、置钉在骨内的体积及松动情况。[结果]3组患者平均手术时间差异具有统计学意义(P<0.001),且每两组间平均手术时间差异也具有统计学意义(P<0.001),嵴下组手术时间最短为(15±5)min,髋臼组最长为(66±10 min)。3组平均出血量差异具有统计学意义(P<0.001),其中嵴下组平均出血量为(20±5)ml,而髋臼组(100±35 ml)和嵴上组(90±50 ml)间出血量差异无统计学意义(P=0.443)。3组患者术后功能恢复Majeed评分优良率,嵴上组61.33%,嵴下组82.5%,髋臼组95.65%,组间比较差异具有统计学意义(P<0.001),髋臼组术后功能恢复情况好于其他2组。神经损伤率:嵴上组0%,嵴下组17.5%,髋臼组4.35%,3组间比较差异具有统计学意义(P<0.05)。髋臼组虽有较低的钉道感染率(8.69%),但与嵴上组(26.67%)及嵴下组(32.5%)组间比较差异无统计学意义。在所把持的骨量方面,3组间差异无统计学意义(P=0.059),而松动率差异具有统计学意义(P<0.05),组间比较髋臼组(2.61%)明显低于其他两组,嵴上组(20.00%)和嵴下组(33.33%)比较差异无统计学意义。[结论]嵴下固定作为急救的处理时较为合适,髋臼上固定适合于可能将外固定支架作为终极治疗的人群,嵴上固定在综合对比中无显著优势。     

An aiming device for pin fixation at the iliac crest for external fixation in unstable pelvic fracture

To improve the accuracy of pinning at the iliac crest during external fixation of the pelvic fracture, an aiming device has been designed. The device consists of 3 parts: a sleeve which accommodates a 5.0 Shanz pin, a handle and guide points. The guide points were designed to grasp the iliac crest to allow proper pin fixation. The device has undergone trials to fix Shanz pins on the iliac crests of 10 cadavers by 10 recently graduated doctors. All pins were fixed in proper position and passed into the bone between the two tables of the iliac crest without penetrating the tables. The device has so far been used in 50 patients who had unstable pelvic fractures. All pins were in the proper positions and there had been no loosening at the time the pins were removed. The use of this aiming device for pinning the iliac crest for external fixation of pelvic fracture has given encouraging results.     

Simple anterior pelvic external fixation

BACKGROUND: Unstable pelvic ring disruptions are often associated with significant morbidity and mortality, especially in patients with multiple injuries. Early pelvic fixation provides stability and should diminish ongoing hemorrhage. A simple anterior single-pin pelvic external fixator can be applied rapidly and accurately to stabilize pelvic ring injuries as a part of the initial patient resuscitation of such patients. Simple anterior pelvic external fixation (SAPEF) frames can be used as either temporary, definitive, or supplementary fixation depending on the pelvic injury pattern. METHODS: Over a 32-month period, 41 patients with unstable pelvic ring disruptions were stabilized using a simple anterior pelvic external fixator. Eight patients had open pelvic ring injuries and 13 others had genitourinary system disruptions. Fluoroscopic imaging was used to insert all of the fixation pins into the iliac crest between the iliac cortical tables to a depth of at least 5 cm. Each patient had closed manipulative reduction of the pelvic ring using external methods before SAPEF application. RESULTS: One patient died less than 24 hours after injury because of torrential hemorrhage. Clinical evaluations and serial radiographs, including postoperative computed tomographic scans, were available for the other 40 patients postoperatively. Seventy-five of the 80 (94%) pins were completely contained between the iliac cortical tables, according to the computed tomographic scans. The initial pelvic closed reductions were maintained until the fixators were removed in 37 of 40 patients (93%). Only one deep pin track infection developed, mandating early frame removal and intravenous antibiotic therapy. CONCLUSION: Simple anterior pelvic external fixation can be applied rapidly using fluoroscopic guidance to direct accurate pin insertion and closed manipulative reduction of the pelvis. Depending on the specific pelvic ring injury pattern and clinical scenario, SAPEF can serve as a resuscitative temporary fixation device, as definitive pelvic treatment, or as a supplement for pelvic internal fixation implants.     

Oblique distraction external pelvic fixation

Simple anterior pelvic external fixation is a safe and effective strategy for reduction of pelvic ring deformity as well as the provisional or definitive stabilization of selected patterns of pelvic ring disruption. A two-pin oblique anterior pelvic deformity correction frame is a unique frame configuration designed to reduce and stabilize lateral compression pelvic ring disruptions associated with flexion/internal rotation hemipelvic deformities. In a small case series, we demonstrate that the oblique distraction external fixation frame alone or in combination with internal fixation is a simple and safe strategy for reduction and stabilization of unstable multiplanar hemipelvic deformities associated with partial posterior ring stability.     

The care of pin sites with external fixation

Two protocols for the operative technique and care of the pin-site with external fixation were compared prospectively. There was a total of 120 patients with 46 in group A and 74 in group B. Infection was defined as an episode of pain or inflammation at a pin site, accompanied by a discharge which was either positive on bacterial culture or responded to a course of antibiotics. Patients in group B had a lower proportion of infected pin sites (p = 0.003) and the time to the first episode of infection was longer (p < 0.001). The risk of pin-site infection is lower if attention is paid to avoiding thermal injury and local formation of haematoma during surgery and if after-care includes the use of an alcoholic antiseptic and occlusive pressure dressings.     

Immediate external fixation of unstable pelvic fractures

Immediate external fixation has been proposed as a means of stabilizing severe pelvic fractures to reduce the chance of organ failure and death. Sixty-six patients were admitted from January 1980 through December 1983 with double fractures of the pelvic ring that involved the posterior elements. Twenty-six patients (39 percent) underwent immediate external fixation for instability, and 40 patients (61 percent) with stable fractures were treated with bed rest. The two groups were similar in age, injury severity score, and degree of shock. The mortality rate of the two groups was the same (12 percent), as was the incidence of organ failure. The mean transfusion requirement in the unstable group was greater, but not significantly. Our results were better than those reported in recent studies in which immediate rigid fixation was not used. We conclude that the patient with multiple trauma without unstable pelvic fracture should undergo immediate external fixation to decrease morbidity and mortality rates and limit soft tissue damage.     

可调式骨盆外固定架治疗不稳定性骨盆骨折

2007年3月～2011年1月,我科应用可调式骨盆外固定架治疗不稳定性骨盆骨折48例,临床效果满意,报道如下。1材料与方法1.1器械开口器和钻孔器(见图1):开口器尖部呈三棱锥样,长约1 cm,较     

Biomechanical analysis of pin placement and pin size for external fixation of distal radius fractures

A series of biomechanical analyses were performed to explain the recent reduction in treatment-related complications of external fixation of distal radius fractures using a limited open approach for pin placement and larger 4-mm self-tapping half pins. A comparison of pull-out strength, stress concentration effect, and inherent bending strength of 3- and 4-mm half pins was performed. The effect of proximal pin placement in the radius or in the ulna and the effect of distal pin placement in four, six, or eight metacarpal cortices were determined. These analyses demonstrate that the 4-mm self-tapping half pins result in a significantly higher pull-out strength and only a small decrease in torsional load strength of the bone. They also demonstrate that proximal pin fixation in the radius produces the most stable fixation and that distal pin fixation into six metacarpal cortices produces a strong configuration that does not violate the interosseous muscles of the second intrinsic compartment. The rate of treatment-related complications in the external fixation of distal radius fractures (specifically, pin loosening, bending and breakage, fracture through pin sites, collapse at the fracture site, and intrinsic contracture) are addressed in this study. Such complications can be minimized by using 4-mm pins after central predrilling, with proximal placement in the radius and distal placement through six cortices of the bases of the second and third metacarpals.     

Easily removed drill guide for pin insertion during external fixation

A new guide for tissue protection while drilling and inserting screws in external fixation without taking down the system is presented. It can be used for pin insertion in both unilateral and ring-type external fixators. The external fixator is used as a template guide, and pin insertion can be easily performed with the fixator in place. With its use, operative time is decreased, and tissue protection is achieved for all pin insertions in any part of the musculoskeletal system.     

The role of external fixation in pelvic disruptions

External fixation has a definite role in the management of pelvic fractures. Biomechanically, it is not useful for maintaining reduction of the unstable, vertically migrating pelvis and must be used with some other form of treatment, such as traction, spica cast, or internal fixation. In vertically stable fractures, that is, rotationally unstable fractures, the anteroposterior and lateral compression injuries, the external fixator should probably be the first course of treatment.     

A safer pin position for external fixation of distal radial fractures

Injury or entrapment of the superficial radial nerve is common in external fixation for fractures of the distal radius. However, by insertion of the half pins dorsally (rather than dorso-radially) in the diaphysis of radius, the nerve should be safe. None of the 40 patients we treated with this safer position of the pins developed symptoms related to the superficial radial nerve.     

Distraction external fixation in lateral compression pelvic fractures

OBJECTIVE: To observe the results and describe the technique of closed reduction and placement of a two-pin supra-acetabular external fixator, followed by immediate weight bearing, in the treatment of displaced vertically stable lateral compression pelvic fractures. DESIGN: Prospective, consecutive SETTING: Regional trauma center PATIENTS: A consecutive series of fourteen patients with displaced, vertically stable lateral compression pelvic fractures who were transported to a regional trauma center. INTERVENTION: Surgical treatment with closed reduction and maintenance of the distraction force with a two-pin, single-bar, supra-acetabular external fixator, followed by immediate weight bearing. MAIN OUTCOME MEASUREMENTS: Healing rate and time, operative blood loss and time, quality of reduction, time to full weight-bearing, and incidence of complications, including neurovascular deficits, loss of reduction, nonunion, pin tract infections, and chronic pain. RESULTS: A symmetric reduction of both hemipelves was achieved in all fourteen patients. Time to healing averaged 8.2 weeks (seven to twelve weeks), and no fixator required removal before healing. There were no delayed unions or nonunions, and none of the fractures displaced significantly after initial reduction. Average surgical time was thirty-seven minutes (range, twenty-five to sixty minutes) with an estimated blood loss of less than fifty milliliters. Patients were allowed to bear full weight immediately and were able to do so without ambulatory assistive devices within an average of twelve days (range, three to eighteen days). Complications consisted of three minor pin tract infections, one temporary lateral femoral cutaneous nerve palsy, one late pin tract abscess, and one patient with chronic low-back pain. CONCLUSIONS: Treatment of type B lateral compression injuries of the pelvic ring with anterior distraction external fixation is a highly effective yet relatively simple and minimally invasive treatment method. Surgical time and blood loss are minimal, and patients can be effectively and rapidly mobilized. Based on our experience, we believe this method to be a valuable tool in the treatment of these fractures.     

Conventional bicortical pin substitution with a novel unicortical pin in external fixation: A biomechanical study

IntroductionAs most patients with polytrauma or open fractures are converted from temporary external fixation to definite stabilization, the prevention of complications such as infection is especially important. To overcome the high risk of infection associated with the use of the conventional bicortical pin for temporary external fixation, the authors developed a novel unicortical pin and analyzed it in a biomechanical study.MethodsThe unicortical pin consisted of an inner screw, purchasing the cortical bone, and an outer sleeve with 6 spikes. A bicortical pin was used for the purpose of comparison. A fracture gap model was stabilized using a monoplanar configuration. Both the unicortical pins (Uni group) and bicortical pins (Bi group) underwent axial compressive and torsional load testing using a servo-hydraulic testing machine. Stiffness, load to failure, and mode of failure were documented.ResultsStiffness and load to failure of the Uni group (average, 40.5 N/mm and 1098.4 N, respectively) were greater than that of the Bi group (average, 33.7 N/mm and 968.6 N, respectively) in the axial compressive load test (P = 0.008 and 0.032). Stiffness and load to failure of the Uni group (average, 1.2 Nm/degree and 1.7 Nm, respectively) were also significantly higher than those of the Bi group (average, 0.8 Nm/degree and 0.6 Nm, respectively) in the torsional load test (P = 0.008 and 0.016). All pins in the Bi group were bent at the pin-synthetic bone interface without synthetic bone failure. Contrarily, the Uni group did not show any pin bending or failure. However, in the axial compression test, partial cracks in the synthetic bone were found at the interface with spikes in the outer shell. In addition, in the torsion test, incomplete fractures were seen through the inner screws' holes.ConclusionCompared with the conventional bicortical pin, the newly designed unicortical pin significantly increased fracture stability under both axial compressive and torsional loads. The unicortical pin can be considered an alternative biomechanical solution to obtain adequate stability when performing external fixation of fractures.