TY - JOUR
T1 - Rod fractures in thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis
T2 - long-term follow-up of a prospective, multicenter cohort of 160 patients
AU - Sardi, Juan Pablo
AU - Lazaro, Bruno
AU - Smith, Justin S.
AU - Kelly, Michael P.
AU - Dial, Brian
AU - Hills, Jeffrey
AU - Yanik, Elizabeth L.
AU - Gupta, Munish
AU - Baldus, Christine R.
AU - Yen, Chun Po
AU - Lafage, Virginie
AU - Ames, Christopher P.
AU - Bess, Shay
AU - Schwab, Frank
AU - Shaffrey, Christopher I.
AU - Bridwell, Keith H.
N1 - Publisher Copyright:
©AANS 2023, except where prohibited by US copyright law.
PY - 2023/2
Y1 - 2023/2
N2 - OBJECTIVE Previous reports of rod fracture (RF) in adult spinal deformity are limited by heterogeneous cohorts, low follow-up rates, and relatively short follow-up durations. Since the majority of RFs present > 2 years after surgery, true occurrence and revision rates remain unclear. The objectives of this study were to better understand the risk factors for RF and assess its occurrence and revision rates following primary thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis (ASLS) in a prospective series with long-term follow-up. METHODS Patient records were obtained from the Adult Symptomatic Lumbar Scoliosis–1 (ASLS-1) database, an NIH-sponsored multicenter, prospective study. Inclusion criteria were as follows: patients aged 40–80 years undergoing primary surgeries for ASLS (Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20 or Scoliosis Research Society-22r ≤ 4.0 in pain, function, and/or self-image) with instrumented fusion of ≥ 7 levels that included the sacrum/pelvis. Patients with and without RF were compared to assess risk factors for RF and revision surgery. RESULTS Inclusion criteria were met by 160 patients (median age 62 years, IQR 55.7–67.9 years). At a median followup of 5.1 years (IQR 3.8–6.6 years), there were 92 RFs in 62 patients (38.8%). The median time to RF was 3.0 years (IQR 1.9–4.54 years), and 73% occurred > 2 years following surgery. Based on Kaplan-Meier analyses, estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Baseline radiographic, clinical, and demographic characteristics were similar between patients with and without RF. In Cox regression models, greater postoperative pelvic tilt (HR 1.895, 95% CI 1.196–3.002, p = 0.0065) and greater estimated blood loss (HR 1.02, 95% CI 1.005–1.036, p = 0.0088) were associated with increased risk of RF. Thirty-eight patients (61% of all RFs) underwent revision surgery. Bilateral RF was predictive of revision surgery (HR 3.52, 95% CI 1.8–6.9, p = 0.0002), while patients with unilateral nondisplaced RFs were less likely to require revision (HR 0.39, 95% CI 0.18–0.84, p = 0.016). CONCLUSIONS This study provides what is to the authors’ knowledge the highest-quality data to date on RF rates following ASLS surgery. At a median follow-up of 5.1 years, 38.8% of patients had at least one RF. Estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Greater estimated blood loss and postoperative pelvic tilt were significant risk factors for RF. These findings emphasize the importance of long-term follow-up to realize the true prevalence and cumulative incidence of RF.
AB - OBJECTIVE Previous reports of rod fracture (RF) in adult spinal deformity are limited by heterogeneous cohorts, low follow-up rates, and relatively short follow-up durations. Since the majority of RFs present > 2 years after surgery, true occurrence and revision rates remain unclear. The objectives of this study were to better understand the risk factors for RF and assess its occurrence and revision rates following primary thoracolumbar fusions to the sacrum/pelvis for adult symptomatic lumbar scoliosis (ASLS) in a prospective series with long-term follow-up. METHODS Patient records were obtained from the Adult Symptomatic Lumbar Scoliosis–1 (ASLS-1) database, an NIH-sponsored multicenter, prospective study. Inclusion criteria were as follows: patients aged 40–80 years undergoing primary surgeries for ASLS (Cobb angle ≥ 30° and Oswestry Disability Index ≥ 20 or Scoliosis Research Society-22r ≤ 4.0 in pain, function, and/or self-image) with instrumented fusion of ≥ 7 levels that included the sacrum/pelvis. Patients with and without RF were compared to assess risk factors for RF and revision surgery. RESULTS Inclusion criteria were met by 160 patients (median age 62 years, IQR 55.7–67.9 years). At a median followup of 5.1 years (IQR 3.8–6.6 years), there were 92 RFs in 62 patients (38.8%). The median time to RF was 3.0 years (IQR 1.9–4.54 years), and 73% occurred > 2 years following surgery. Based on Kaplan-Meier analyses, estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Baseline radiographic, clinical, and demographic characteristics were similar between patients with and without RF. In Cox regression models, greater postoperative pelvic tilt (HR 1.895, 95% CI 1.196–3.002, p = 0.0065) and greater estimated blood loss (HR 1.02, 95% CI 1.005–1.036, p = 0.0088) were associated with increased risk of RF. Thirty-eight patients (61% of all RFs) underwent revision surgery. Bilateral RF was predictive of revision surgery (HR 3.52, 95% CI 1.8–6.9, p = 0.0002), while patients with unilateral nondisplaced RFs were less likely to require revision (HR 0.39, 95% CI 0.18–0.84, p = 0.016). CONCLUSIONS This study provides what is to the authors’ knowledge the highest-quality data to date on RF rates following ASLS surgery. At a median follow-up of 5.1 years, 38.8% of patients had at least one RF. Estimated RF rates at 2, 4, 5, and 8 years after surgery were 11%, 24%, 35%, and 49%, respectively. Greater estimated blood loss and postoperative pelvic tilt were significant risk factors for RF. These findings emphasize the importance of long-term follow-up to realize the true prevalence and cumulative incidence of RF.
KW - adult scoliosis
KW - lumbar
KW - rod fracture
KW - spinal alignment
KW - spinal instrumentation
KW - spine deformity
KW - spine surgery
KW - thoracic
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U2 - 10.3171/2022.8.SPINE22423
DO - 10.3171/2022.8.SPINE22423
M3 - Article
C2 - 36461845
AN - SCOPUS:85147309335
SN - 1547-5654
VL - 38
SP - 217
EP - 229
JO - Journal of Neurosurgery: Spine
JF - Journal of Neurosurgery: Spine
IS - 2
ER -