The flying buttress construct for posterior spinopelvic fixation: a technical note

Rescue Pelvic Fixation in a Patient with Sacral-2-Alar-Iliac and Triangular Sacroiliac Joint Fusion (Bedrock) Instrumentation

The purpose of this report is to demonstrate the creation of a 4-rod lumbosacral construct, when "stacked" sacral-2-alar-iliac (S2AI) screws are not possible due to a concurrent treatment of sacroiliitis with a posterior approach sacroiliac joint fusion device. This technique uses a combined S2AI and subcrestal iliac approach to achieve the 4-rod lumbosacral construct, while simultaneously biomechanically supporting the S2AI screws and treating the sacroiliitis.

Utilization of Offset Iliac Connectors as Anchoring Sites in Severe Rigid Scoliosis: New Technique

STUDY DESIGN

This was a prospective cohort study.

OBJECTIVES

To introduce the iliac connectors as fixation options in spinal constructs used for correction of severe scoliosis at locations other than the lumbopelvic region.

METHODS

Nine patients with severe rigid scoliosis undergoing surgical release and posterior instrumentation in the period between January 2013 and January 2015 were included in this prospective cohort study. Mean age was 18.4 years; 8 had triple structural curves, and the remaining patient had double structural curves. Cobb angles of the primary and compensatory curves were compared with the immediate, 1-year, and 2-year postoperative measurements using the F test, with P value ≤.05 indicating statistical significance. Screw densities of the final constructs were calculated and compared with the screw densities when the offset iliac connectors were not used.

RESULTS

One to 4 offset iliac connectors were used in all 9 patients, increasing screw density by a mean of 6.24 (P < .001). The mean Cobb angle of the major curve was corrected from 98.44° to 58.2° (P < .001), that of the first compensatory curve, from 56.55° to 38.33° (P < .001), and that of the second compensatory curve, from 40.75° to 26.63° (P < .001). There were no intraoperative neurological complications. After a mean follow-up of 30.6 months, the construct remained stable in all patients with no loss of correction.

CONCLUSION

Offset iliac connectors can be a valuable tool to increase screw density in correction of severe scoliosis, thus increasing overall biomechanical strength of the final construct.

A comprehensive biomechanical analysis of sacral alar iliac fixation: an in vitro human cadaveric model

In BriefIn this in vitro investigation, we compared the multidirectional flexibility properties of sacral alar iliac fixation with conventional methods of sacral and sacroiliac fixation using nondestructive and destructive investigative methods. The study demonstrated that S1-2 sacral fixation alone significantly increases sacroiliac motion under all loading modalities, while sacral alar iliac fixation reduced motion in axial rotation at the sacroiliac joint and offers potential advantages of a lower instrumentation profile and ease of assembly compared to conventional sacroiliac screw instrumentation.