RESUMO
Background: For patients undergoing long-construct fusion surgeries, simultaneous sacroiliac joint (SIJ) fusion is a growing trend in spine surgery. Some options for posterior SIJ fusion include 3D-printed triangular titanium implants or self-harvesting SIJ screws. Both implants require fixation within the sacrum and ileum. Fat embolism syndrome is a rare but known complication of lumbar pedicle instrumentation but has never been reported in association with SIJ fusion, regardless of implant type. We report the first two known cases of fat embolism associated with placement of SIJ fusion devices during long construct posterior spine fusion. Case Description: Case 1-a 50-year-old female with multiple previous spine surgeries complicated by osteomyelitis/diskitis that was successfully eradicated, underwent T10-pelvis posterior spinal fusion (PSF), L4 pedicle-subtracting-osteotomy, and bilateral SIJ fusion. During implantation of each SIJ fusion device, the patient's hemodynamic status deteriorated necessitating vasopressor support, intravenous fluid bolus, and hyperventilation, but quickly resolved. The case was completed without further issue, and she had an uneventful post-operative course. Case 2-a 71-year-old female with a past medical history of ankylosing spondylitis, previous L2-L5 PSF, rheumatoid arthritis on chronic steroids, underwent a T9-pelvis PSF, bilateral SIJ fusion, L4 pedicle subtraction osteotomy, T10-L1 Smith Peterson osteotomies. After implantation of the second SIJ fusion device, she became hypotensive and tachycardic, pulses were absent, and cardiopulmonary resuscitation was initiated. Pulses returned quickly, the index surgery was terminated, and she was transferred to the intensive care unit (ICU). In the ICU she was quickly weaned off the ventilator on post-operative day 1. On post-operative day 4, the patient returned to the operating room for completion of the surgery and had an extended, but uneventful, recovery afterwards. Conclusions: We report on the first two known cases of fat embolism syndrome occurring immediately after implantation of SIJ fusion devices. Spine surgeons should be aware of this rare, but potentially fatal, complication. Collaboration with the anesthesia team and optimization of the patient's hemodynamic status prior to implantation may help prevent catastrophic complications.
RESUMO
BACKGROUND: Horizontal, degenerative tears of the medial meniscus and subsequent meniscectomy can compromise the biomechanical function of the meniscus in load transmission and weightbearing, leading to the development of radiographic and symptomatic tibiofemoral arthritis. HYPOTHESIS: Resection of both leaflets of a horizontal medial meniscal tear will increase peak contact pressures and decrease contact areas in comparison with resection of only the inferior leaflet. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen human cadaveric knees had tibiofemoral peak contact pressures and contact areas under an 1800-N axial load measured by Tekscan in the control state. A horizontal tear was created in the posterior horn of the medial meniscus, and the knees were retested. The knees were tested a third time after resection of the inferior leaflet (single leaflet) and a final time after resection of the superior leaflet (both leaflets). The Friedman test was used to test for group differences in peak pressure (psi) and contact area (mm(2)) between test conditions (native, tear, inferior leaflet resection, and resection of both leaflets). RESULTS: For the medial compartment, there was a statistically significant difference in peak pressure (P = .03) but not in contact area (P = .70) between testing conditions. Median peak pressure in the medial compartment was significantly greater for resection of both leaflets compared with the tear (406.5 vs 294.7 psi, respectively; P = .002). Median contact area in the medial compartment was greatest for resection of both leaflets (602.7 mm(2)), but there were no statistically significant differences between test conditions (P = .70). For the lateral compartment, there were no statistically significant differences in peak pressure (P = .99) or contact area (P = .77) between test conditions. CONCLUSION: Resection of a single inferior leaflet after a horizontal medial meniscal tear preserves much of the original biomechanical function of the meniscus. Resection of both leaflets leads to a significant increase in contact pressure dispersed over the same contact area, which results in an undesirable biomechanical environment. CLINICAL RELEVANCE: Arthroscopic inferior leaflet resection is a viable option for providing symptomatic relief of horizontal medial meniscal tears and preserves the ability of the meniscus to absorb axial loading on the knee joint, theoretically decreasing the risk of subsequent osteoarthritis.
