Sacral insufficiency fractures after lumbosacral arthrodesis: salvage lumbopelvic fixation and a proposed management algorithm

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Sacral insufficiency fracture after lumbosacral (LS) arthrodesis is an uncommon complication. The objective of this study was to report the authors’ operative experience managing this complication, review pertinent literature, and propose a treatment algorithm.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>The authors analyzed consecutive adult patients treated at their institution from 2009 to 2018. Patients who underwent surgery for sacral insufficiency fractures after posterior instrumented LS arthrodesis were included. PubMed was queried to identify relevant articles detailing management of this complication.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Nine patients with a minimum 6-month follow-up were included (mean age 73 ± 6 years, BMI 30 ± 6 kg/m<jats:sup>2</jats:sup>, 56% women, mean follow-up 35 months, range 8–96 months). Six patients had osteopenia/osteoporosis (mean dual energy x-ray absorptiometry hip T-score −1.6 ± 0.5) and 3 received treatment. Index LS arthrodesis was performed for spinal stenosis (n = 6), proximal junctional kyphosis (n = 2), degenerative scoliosis (n = 1), and high-grade spondylolisthesis (n = 1). Presenting symptoms of back/leg pain (n = 9) or lower extremity weakness (n = 3) most commonly occurred within 4 weeks of index LS arthrodesis, which prompted CT for fracture diagnosis at a mean of 6 weeks postoperatively. All sacral fractures were adjacent or involved S1 screws and traversed the spinal canal (Denis zone III). H-, U-, or T-type sacral fracture morphology was identified in 7 patients. Most fractures (n = 8) were Roy-Camille type II (anterior displacement with kyphosis). All patients underwent lumbopelvic fixation via a posterior-only approach; mean operative duration and blood loss were 3.3 hours and 850 ml, respectively. Bilateral dual iliac screws were utilized in 8 patients. Back/leg pain and weakness improved postoperatively. Mean sacral fracture anterolisthesis and kyphotic angulation improved (from 8 mm/11° to 4 mm/5°, respectively) and all fractures were healed on radiographic follow-up (mean duration 29 months, range 8–90 months). Two patients underwent revision for rod fractures at 1 and 2 years postoperatively. A literature review found 17 studies describing 87 cases; potential risk factors were osteoporosis, longer fusions, high pelvic incidence (PI), and postoperative PI-to–lumbar lordosis (LL) mismatch.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>A high index of suspicion is needed to diagnose sacral insufficiency fracture after LS arthrodesis. A trial of conservative management is reasonable for select patients; potential surgical indications include refractory pain, neurological deficit, fracture nonunion with anterolisthesis or kyphotic angulation, L5–S1 pseudarthrosis, and spinopelvic malalignment. Lumbopelvic fixation with iliac screws may be effective salvage treatment to allow fracture healing and symptom improvement. High-risk patients may benefit from prophylactic lumbopelvic fixation at the time of index LS arthrodesis.</jats:p></jats:sec>

Sacral Insufficiency Fracture Following Short-Segment Lumbosacral Fusion: Case Series and Review of the Literature

“…Some have implicated an increased PI, increased BMI, age, and gender as risk factors for sacral fractures after all lumbosacral spinal fusions. This cohort was younger (mean age 58 years) than reports of sacral fracture after long-segment fusion 31,32 and had a similar incidence between men and women (55% female). Many patients were obese or morbidly obese in this series with a mean BMI of 30 kg/m 2 , which follows previous reports that increased weight may be a risk factor for sacral fracture after lumbosacral fusion.…”

“…This is a similar algorithm to that recommended by Buell et al for sacral fractures after spinal fusion including long-segment fusions. 31 To adequately control the lumbosacral junction revision posterior spinal fusion should extend to the pelvis with either iliac screws or S2AI screws; however, revision of a stand-alone ALIF has been reported to be successfully achieved with L5-S1 PSF alone, avoiding implant issues related to extending to the pelvis. Patients with continued pain, but who are poor surgical candidates may benefit from interventional sacroplasty, 47 - 49 but long-term outcomes are sparse and require more research.…”

“…These reports describe risk factors such as osteoporosis, obesity, and gender, but given the low overall incidence, the true incidence and factors remain unknown. [23][24][25][26][27][28][29][30][31][32] The purpose of this study was to review the current literature and our institutional experience to better describe the patient characteristics, presentation, evaluation, treatment options, and outcomes for these patients with sacral insufficiency fracture after L4-S1 or L5-S1 fusion.…”

“…These reports describe risk factors such as osteoporosis, obesity, and gender, but given the low overall incidence, the true incidence and factors remain unknown. 23 - 32 …”

Superiority of MRI for Evaluation of Sacral Insufficiency Fracture

“…Sacral insufficiency fractures (SIF) have been commonly reported in patients with severe osteoporosis [ 4 ], long spinal fusion [ 5 ], and pelvic irradiation [ 6 ]. Typically, patients had no history of trauma [ 7 ] and no specific symptoms compared with other lumbar spine pathologies [ 8 ].…”