Introduction:
Fragility fractures of the pelvis (FFPs) are a distinct type of pelvic fracture caused by minor trauma, primarily affecting older individuals with osteoporosis - a condition characterized by bone weakening, heightening fracture risk even with slight impact. These fractures are notably more prevalent in women over 55 and men over 65. For Type 3A FFPs involving a displaced posterior ilium fracture with an anterior pelvic ring fracture, surgeons often employ iliac intramedullary stabilization (ILIS), a minimally invasive surgical technique aimed at internal fixation. Read below to learn more about this surgical technique.
What Are Fragility Fractures of the Pelvis?
Fragility fractures of the pelvis result from low-energy trauma, like falls, particularly affecting older individuals with osteoporosis. In 2013, Rommens et al. introduced a classification system for these fractures, categorizing them into types 1 through 4. Type 3 fractures, constituting 11 percent of all fragility pelvic fractures, are managed with Iliac intramedullary stabilization. These type 3 fractures encompass three subtypes, which are:
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Type 3 A: These fractures are characterized by fractures in the iliac region and stand out as the most prevalent subtype, representing 8.2 percent of all fragility fractures of the pelvis.
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Type 3 B: These fractures pertain to specific fractures that affect the sacroiliac joint.
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Type 3 C: These fractures involve fractures within the sacral region.
How Do Type 3A Fragility Fractures of the Pelvis Appear on Radiographs?
Type 3A fragility fractures of the pelvis display distinct radiographic features:
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The ilium (a component of the pelvic bone) demonstrates external rotation.
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The obturator foramen on the side of the fracture appears diminished in size.
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The sacrotuberous and sacrospinous ligaments remain undisturbed and intact.
In Which Case Iliac Intramedullary Stabilization Can Be Utilized?
Iliac intramedullary stabilization is a specialized approach employed for certain pelvic fractures, specifically those complicated by sacral and sacroiliac joint disruptions. This technique is predominantly utilized in type 3 fragility fractures of the pelvis, which are often complex and unstable, necessitating surgical intervention to achieve effective stabilization. Such fractures are more prevalent in elderly patients with osteoporosis, highlighting the critical need for targeted surgical management to optimize patient outcomes.
What Is Iliac Intramedullary Stabilization?
This minimally invasive surgical procedure is specifically employed to address type 3 fragility fractures of the pelvis, where the sacrotuberous and sacrospinous ligaments remain unharmed. These ligaments are crucial for stabilizing the pelvis, and their intact nature limits the movement of fractured fragments by serving as natural anatomical boundaries. Based on radiographic findings, Type 3A fragility fractures of the pelvis exhibit external rotation of the ilium and a reduction in the size of the obturator foramen on the side affected by the fracture. The main objective of surgical intervention for Type 3A FFPs is to restore functional stability, prioritizing overall function over achieving complete anatomical reduction.
The procedural steps involved in addressing Type 3A FFPs typically include:
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Patient Positioning: The patient is positioned in a prone (face-down) orientation for the surgical procedure. To access the underlying structures, bilateral incisions measuring 1.1 to 1.5 inches are carefully made directly above the posterior superior iliac spine (PSIS).
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Preparing for Implant Placement: To prepare for implant placement, a groove approximately 1.1 inches wide is carefully fashioned at the posterior superior iliac spine (PSIS) using a chisel to remove the bone. This step is crucial for accommodating the implants and minimizing the risk of skin irritation or postoperative complications by embedding the screw heads within the PSIS. Following this, the muscles on the dorsal (back) surface of the sacrum are meticulously dissected to gain access to the underlying structures. Subsequently, the sacrum's spinal processes (bony projections) are methodically cut using a chisel, creating a tunnel that establishes connectivity between the left and right sides.
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Femur Internal Rotation Reduction Method (FIRM) Technique: The procedure begins with a closed reduction technique known as the femoral internal rotation method (FIRM), aimed at realigning fractured pelvic fragments by internally rotating the femur (thigh bone). This manipulation of the femur causes a corresponding adjustment in the position of the pelvic fragments, facilitated by the manipulation of lateral rotator muscles and surrounding soft tissues. To achieve reduction, the patient is positioned face down while the ankle is grasped and the knee is bent, enabling controlled internal rotation of the femur. During this procedure, changes can be observed on X-ray imaging, including the gradual restoration of the shape of the obturator foramen towards a more normal appearance and improved alignment of the pelvic bones.
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Fixation Using Spinal Instruments: Following the femoral internal rotation method procedure, a path is meticulously created from the bone groove at the posterior superior iliac spine (PSIS) to the anterior inferior iliac spine (AIIS) using probes, navigating through the supra-acetabular bone canal. Screws are then carefully inserted through the supra-acetabular bone canal into the AIIS on both sides of the pelvis. These screws are typically inserted at a length of 80 to 100 mm (millimeter), with their heads positioned at the depth of the dorsal surface of the sacrum. Utilizing two screws instead of one serves to minimize postoperative rotation and displacement of bone fragments, thereby enhancing overall stability. Following the insertion of screws, two transverse rods, and two cross connectors are employed to connect these screws, forming a robust internal fixation system within the pelvis. This assembly effectively stabilizes the fractured pelvic region and supports optimal healing.
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Closure: During the closure of the surgical site, soft tissues, including the thoracolumbar fascia (a complex structure of connective tissue in the lower back region that plays a crucial role in supporting and stabilizing the spine and surrounding muscles), are meticulously sutured to cover the implanted hardware, ensuring adequate protection and promoting favorable recovery outcomes for the patient.
What Is the Prognosis of This Surgical Procedure?
Based on reported data, the duration of the procedure typically ranged from 1.5 hours to 3.5 hours. Studies indicate that bone union was uniformly achieved within six months for all patients who underwent the procedure. Interestingly, patients treated with the described method exhibited accelerated weight-bearing capabilities, with some individuals bearing weight as early as three weeks post-surgery and others even on the first day following the procedure.
According to study findings, overall surgical outcomes were successful. However, certain postoperative complications were noted in specific cases. These complications included delayed wound healing, the development of pressure ulcers, and instances of deep infection. Notably, no implant rupture or secondary displacement occurrences were reported in the study cohort.
Conclusion:
Type 3 fragility fractures of the pelvis are characterized by instability, making conservative management challenging and often ineffective. Surgical intervention is recommended for these fractures due to their unstable nature and the complexity of achieving proper reduction and fixation through non-surgical means. Iliac intramedullary stabilization offers a less invasive fixation technique that provides stability with minimal disruption to surrounding tissues. This approach utilizes dual screws inserted on both sides of the fracture site to enhance stability and reduce the likelihood of postoperative complications, such as rotation or displacement of bone fragments. By employing this method, surgeons aim to optimize fracture reduction and promote successful healing while minimizing surgical trauma and associated risks.
