Open Versus Minimally Invasive Fixation for Unstable Sacral Fractures in Adults

Traumatic unstable sacral fractures are challenging high-energy pelvic injuries with significant implications for structural integrity and neurological function. While traditional open lumbopelvic fixation (O-LPF) provides excellent biomechanical stability and allows for direct neural decompression, it requires an extensile posterior approach associated with significant perioperative morbidity, including deep surgical site infection rates historically ranging from 16% to 26%. Minimally invasive or percutaneous lumbopelvic fixation (MIS-LPF) was developed to mitigate these approach-related complications, though it permits only indirect neural decompression.

Despite emerging evidence favoring MIS techniques for reduced blood loss and infection rates, most published series remain small, retrospective, and heterogeneous. This study aims to provide a comprehensive, multi-dimensional comparison of open versus minimally invasive lumbopelvic fixation specifically in adult patients with traumatic unstable sacral fractures.

This is a retrospective, comparative cohort study conducted at the Department of Orthopedic Surgery and Traumatology at Assiut University. Data will be systematically extracted by two independent investigators from electronic medical records, surgical operative logs, and PACS digital imaging systems for qualifying index surgeries performed between January 2016 and December 2024. A standardized data extraction sheet will be utilized to minimize observer bias, and all data will be de-identified prior to analysis.

Researchers will collect comprehensive data points across several domains:

• Baseline and Injury Characteristics: Demographics, comorbidities, mechanism of injury, and precise fracture classifications including Denis Zones, Roy-Camille, and AO/OTA.
• Surgical and Perioperative Details: Surgical technique utilized, operative time, estimated blood loss, specific implant details, use of intraoperative imaging, and length of hospital/ICU stay.
• Clinical and Radiological Outcomes: Neurological status documented via the Gibbons Neurological Grading Scale, quality of fracture reduction assessed via Matta and Tornetta criteria, time to radiographic union, and postoperative pain levels via Visual Analog Scale (VAS).
• Complications: Incidence of surgical site infections (superficial and deep), wound dehiscence, implant failure, thromboembolic events, and the necessity and timing of secondary reoperations.

Inclusion criteria

• Adult patients aged 18 years or older at the time of injury and surgery.
• Confirmed diagnosis of a traumatic, unstable sacral fracture, including: Denis Zone I, II, or III fractures with instability; Spinopelvic dissociation (U-type / H-type sacral fractures); AO/OTA Type C pelvic ring injuries involving the sacrum.
• Operated on using lumbopelvic fixation (open or minimally invasive technique) within the study period (2016-2024).
• Availability of adequate and complete medical records, including: Preoperative and postoperative imaging (X-ray and/or CT scan), and operative notes and surgical logs.
• Minimum clinical follow-up of 12 months postoperatively.

Exclusion criteria

• Pathological fractures (e.g., fractures secondary to primary or metastatic malignancy, osteoporotic insufficiency fractures).
• Patients managed conservatively or with alternative fixation strategies that do not include lumbopelvic instrumentation (e.g., isolated iliosacral screw fixation, anterior ring fixation alone).
• Severe polytrauma resulting in in-hospital mortality prior to the minimum required follow-up period.
• History of previous pelvic, sacral, or lumbosacral spine surgery prior to the index trauma.
• Incomplete medical records or inadequate radiological follow-up data preventing accurate assessment of outcomes.
• Patients with pre-existing neuromuscular disorders or spinal pathology that would confound neurological or functional outcome assessment.
• Pregnant patients at the time of injury