Placement Of External Fixation Pins Research Articles

External fixator pin placement during initial management of tibial plateau fractures: are there parameters to minimize pin-plate overlap?

External fixator pin site overlap with definitive fixation implants (pin-plate overlap) has been identified as a risk factor for surgical site infection in tibial plateau fractures. Despite this, pin-plate overlap occurs in 24-38% of patients. This study sought to identify radiographic characteristics associated with pin-plate overlap to help minimize occurrences. 283 patients at two Level I trauma centers were retrospectively reviewed. Radiographic measurements were recorded including fracture length, distance from fracture to proximal tibial pin site, and pin site distance-to-fracture (PSF) ratio. 70 (24.7%) cases of pin-plate overlap were identified. Pin-plate overlap was associated with increased fracture length (81.5 ± 32.1mm vs 56.9 ± 26.1mm, p < 0.001) and decreased distance from fracture to proximal tibial pin site (84.5 ± 37.1mm vs 126.9 ± 35.8mm). Pins placed greater than 100mm and 150mm from the fracture eliminated 36/70 (51%) and 67/70 (96%) pin-plate overlaps, respectively. Pins placed with a PSF ratio greater than 1.5 and 2.0 eliminated 47/70 (67%), and 57/70 (81%) of pin-plate overlaps, respectively. Longer fractures, pins closer to the fracture, and decreased PSF ratio were associated with overlap. Placing proximal tibial pins more than 100mm from the fracture eliminated most pin-plate overlaps.

"Nailable" External Fixation of the Tibia: A Novel Technique to Accommodate Delayed Intramedullary Nailing of the Tibia.

External fixation is often used for temporary stabilization of the tibia in several clinical scenarios. Conventional placement of external fixation pins may impede instrumentation with intramedullary nailing, thus requiring pin removal, loss of reduction, and increased operative time during definite fixation. In this article, we describe a strategic pin placement routinely used at our institution in which we create a medially based inverted triangular construct that allows for pins to remain in place during definitive fixation.

Ultrasound-guided supra-acetabular pelvic external fixator (US-SA FIX)

BackgroundBetween the different options in pelvic external fixation, the supra-acetabular pin placement is considered the best option by many authors. The aim of this study is to describe the surgical technique of the ultrasound-guided supra-acetabular pelvic external fixator (US-SA FIX). Surgical techniqueDescription of the steps to perform the US-SA FIX technique. DiscussionThe supra-acetabular pin placement is considered the best option and it is the most wildly used because it combines three crucial qualities: safety, simplicity, and effectiveness. Notwithstanding, when a severely multiple injured patient arrives at the emergency room we need to perform an emergency external fixation, however trained x-ray technicians or pelvic surgeons are not always present, making it difficult to perform the surgery with the proper intra-operative imaging, increasing the surgical time with potentially serious repercussions, a case scenario where the ultrasound can be a very helpful tool. Ultrasound-guided supra-acetabular pelvic external fixator pin placement is feasible without compromising the reliability of its placement, and the application of this new technique in clinical practice in our centre brings encouraging results.

Neurovascular anatomy around the knee: Relevance of the dangers of self-drilling external fixator pin tips.

Introduction: With external fixation of the femur and tibia, iatrogenic injury to neurovasculature from self-drilling tips of fixation pins is an important consideration in pin placement. Precise knowledge of the neurovascular anatomy in the distal femur and proximal tibia is important to limit potential pin misplacement. Method: Six pin placement sites on six cadaveric legs were used in accordance with current placement techniques. After pin placement, the soft tissue around each pin was dissected and the distances between the pin tips and the surrounding neurovasculature were measured. Results: The resultant data allow for a description of safe and unsafe corridors which can be used for external fixator pin placement. Safe sagittal insertion into the distal femur should consist of two pins: (1) 90 mm ± proximal from the proximal pole of the patella and 3 mm ± medially, (2) 55 mm ± proximal from the proximal pole of the patella and 2 mm ± laterally. Safe coronal insertion into the distal femur should consist of two pins: (1) 30 mm ± proximal to the lateral epicondyle, (2) 100 mm ± proximal to the lateral epicondyle. Safe proximal tibial pin placement should consist of two pins and be placed at an oblique angle: (1) 20 mm ± distal to the tibial tuberosity and 2 mm ± medially, (2) 55 mm ± distal to the tibial tuberosity and 2 mm ± medially. Discussion: This study forms an investigation into the safe areas for placement of external fixator pins, within the distal femur and proximal tibia, specifically, detailing the best practice for pin placement in relation to the tips of the external fixation pins.

The dangers of damage control orthopedics: a case report of vascular injury after femoral fracture external fixation

BackgroundPlacement of external fixation frames is an expedient and minimally invasive method of achieving bone and joint stability in the setting of severe trauma. Although anatomic safe zones are established for placement of external fixation pins, neurovascular structures may be at risk in the setting of severe trauma.Case reportWe present a case of a 21-year-old female involved in a high speed motorcycle accident who sustained a Type IIIB open segmental femur fracture with significant thigh soft tissue injury. Damage control orthopedic principals were applied and a spanning external fixator placed for provisional femoral stabilization. Intraoperative vascular examination noted absent distal pulses, however an intraoperative angiogram showed arterial flow distal to the trifurcation. Immediately postoperatively the dorsalis pedis pulse was detected using Doppler ultrasound but was then non-detectable over the preceding 12-hours. Femoral artery CT angiogram revealed iatrogenic superficial femoral artery occlusion due to kinking of the artery around an external fixator pin. Although the pin causing occlusion was placed under direct visualization, the degree of soft tissue injury altered the appearance of the local anatomy. The pin was subsequently revised allowing the artery to travel in its anatomic position, restoring perfusion.ConclusionThis case highlights the dangers associated with damage control orthopedics, especially when severe trauma alters normal local anatomy. Careful assessment of external fixator pin placement is crucial to avoiding iatrogenic injury. We recommend a thorough vascular examination pre-operatively and prior to leaving the operating room, which allows any abnormalities to be further evaluated while the patient remains in a controlled environment. When an unrecognized iatrogenic injury occurs, serial postoperative neurovascular examinations allow early recognition and corrective actions.

Anatomy of the Lateral Antebrachial Cutaneous and Superficial Radial Nerves in the Forearm: A Cadaveric and Clinical Study

To define the anatomy of the lateral antebrachial cutaneous nerve (LACN) and the superficial radial nerve (SRN) in relation to easily identifiable landmarks in the dorsoradial forearm to minimize the risk to both nerves during surgical approaches to the dorsal radius. In this study 37 cadaveric forearms and 20 patients having distal radius external fixation were dissected to identify these nerves in relation to various anatomic landmarks. Based on these dissections the anatomy was divided into 2 zones that can be identified by easily visible and palpable landmarks. Zone 1 extends from the elbow to the cross-over of the abductor pollicis longus with the extensor carpi radialis brevis and longus. Zone 2 is distal to the cross-over. In zone 1 the 2 nerves can be differentiated through limited incisions based on their depth and anatomic location. Within this zone the SRN is deep to the brachioradialis until 1.8 cm proximal to zone 2 (9 cm proximal to the radial styloid), where it becomes superficial and pierces the fascia of the mobile wad and then remains deep to the subcutaneous fat. In contrast the LACN pierces the fascia between the brachialis and biceps muscles at the level of the elbow. In all specimens the LACN ran parallel to the cephalic vein within the subcutaneous fat. In 31 specimens it ran volar to the vein and in 5 specimens the nerve crossed under the cephalic vein at the elbow and ran dorsal to the vein in the forearm. One specimen had 2 branches with 1 on either side of the vein. Differentiation of these nerves was found to be possible through limited incisions in zone 1 during placement of external fixation pins for distal radius fractures. The LACN always was located in the superficial fat running with the cephalic vein, whereas the SRN was deeper to this nerve either covered by the brachioradialis or closely adherent to it within the investing fascia of the mobile wad. In zone 2 the nerves arborized and ran in the same tissue plane, making differentiation through limited incisions difficult. Dividing forearm anatomy into zones aids in understanding the complex 3-dimensional anatomy. Recognition of the consistent location of both the LACN and SRN facilitates surgical exposure. This allows localization through limited incisions during nerve repair and hardware placement, thereby enhancing uncomplicated and favorable outcomes.

Anatomic and Radiographic Considerations in the Placement of Anterior Pelvic External Fixator Pins

Anatomic and radiographic studies were performed on three cadaveric pelves to define recommendations for better anterior pelvic external fixator pin placement. A thick zone of bone was identified for pin purchase beginning along the iliac crest 2-3 cm posterior to the anterior superior iliac spine (ASIS), and extending 6-8 cm posteriorly along the crest. This zone is hourglass-shaped, and follows the superior gluteal ridge to the superior acetabular region. This zone has a maximal thickness of 4 cm in the supra-acetabular region, and a minimum of 8 mm at the isthmus. Cortical pin penetration is more likely to occur if pin placement begins in the lateral third of the iliac crest, or if the pin is advanced beyond the isthmus of this zone, 5 cm from the crest. Acetabular penetration occurs when the pins are advanced farther than 10.5 cm. Radiographic evaluation demonstrates that only the pelvic outlet view gives the proper orientation of the iliac tables to guide the angle of the pin placement (24 degrees from vertical) and to confirm proper pin placement. Computed tomography (CT) evaluation with "inlet" positioning of the gantry gives complementary information for pin placement.

External fixator pin placement in the forearm: how safe is it? An anatomical study

An anatomical study was undertaken using cadaveric forearms to identify the best technique and angle of pin placement for external fixator pins. We have found that inserting pins through stab incisions risks transfixion of the underlying structures and leads to an increased morbidity. We conclude that inserting pins under direct vision is much safer and that the optimum angle of pin insertion is in the coronal plane, parallel to the plane of the metacarpals.