Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity

International Spine Study Group, Munish C. Gupta

Research output: Contribution to journalArticle

80 Citations (Scopus)

Abstract

OBJECT: Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.

METHODS: This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.

RESULTS: Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8).

CONCLUSIONS: Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.

Original languageEnglish (US)
Pages (from-to)994-1003
Number of pages10
JournalJournal of neurosurgery. Spine
Volume21
Issue number6
DOIs
StatePublished - Dec 1 2014

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Osteotomy
Stainless Steel
Chromium
Cobalt
Titanium
Spine
Body Mass Index
Lordosis
Kyphosis
Counseling
Thorax
Multivariate Analysis
Incidence

Keywords

  • adult
  • ASD = adult spinal deformity
  • BMI = body mass index
  • BMP-2 = recombinant human bone morphogenetic protein–2
  • CCI = Charlson Comorbidity Index
  • complication
  • deformity
  • instrumentation
  • ISSG = International Spine Study Group
  • LL = lumbar lordosis
  • pedicle subtraction osteotomy
  • PI = pelvic incidence
  • PSO = pedicle subtraction osteotomy
  • PT = pelvic tilt
  • rod fracture
  • sagittal imbalance
  • spine
  • surgery
  • SVA = sagittal vertical axis

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. / International Spine Study Group; Gupta, Munish C.

In: Journal of neurosurgery. Spine, Vol. 21, No. 6, 01.12.2014, p. 994-1003.

Research output: Contribution to journalArticle

International Spine Study Group ; Gupta, Munish C. / Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. In: Journal of neurosurgery. Spine. 2014 ; Vol. 21, No. 6. pp. 994-1003.
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title = "Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity",
abstract = "OBJECT: Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.METHODS: This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.RESULTS: Of 287 patients who otherwise met inclusion criteria, 200 (70{\%}) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81{\%} were women; 10{\%} were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25{\%}) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53{\%}, stainless steel (SS), in 26{\%}, or titanium alloy (TA) in 21{\%} of cases; the rod diameters were 5.5 mm (in 68{\%} of cases), 6.0 mm (in 13{\%}), or 6.35 mm (in 19{\%}). RF occurred in 18 cases (9.0{\%}) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0{\%} of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0{\%} to 31.6{\%} across centers. CC rods were used in 68{\%} of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33{\%} vs 0{\%}, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95{\%} CI 2.01-15.8).CONCLUSIONS: Rod fracture occurred in 9.0{\%} of ASD patients and in 22.0{\%} of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.",
keywords = "adult, ASD = adult spinal deformity, BMI = body mass index, BMP-2 = recombinant human bone morphogenetic protein–2, CCI = Charlson Comorbidity Index, complication, deformity, instrumentation, ISSG = International Spine Study Group, LL = lumbar lordosis, pedicle subtraction osteotomy, PI = pelvic incidence, PSO = pedicle subtraction osteotomy, PT = pelvic tilt, rod fracture, sagittal imbalance, spine, surgery, SVA = sagittal vertical axis",
author = "{International Spine Study Group} and Smith, {Justin S.} and Ellen Shaffrey and Klineberg, {Eric Otto} and Shaffrey, {Christopher I.} and Virginie Lafage and Schwab, {Frank J.} and Themistocles Protopsaltis and Scheer, {Justin K.} and Mundis, {Gregory M.} and Gupta, {Munish C.} and Gupta, {Munish C.} and Richard Hostin and Vedat Deviren and Khaled Kebaish and Robert Hart and Burton, {Douglas C.} and Breton Line and Shay Bess and Ames, {Christopher P.}",
year = "2014",
month = "12",
day = "1",
doi = "10.3171/2014.9.SPINE131176",
language = "English (US)",
volume = "21",
pages = "994--1003",
journal = "Journal of neurosurgery. Spine",
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TY - JOUR

T1 - Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity

AU - International Spine Study Group

AU - Smith, Justin S.

AU - Shaffrey, Ellen

AU - Klineberg, Eric Otto

AU - Shaffrey, Christopher I.

AU - Lafage, Virginie

AU - Schwab, Frank J.

AU - Protopsaltis, Themistocles

AU - Scheer, Justin K.

AU - Mundis, Gregory M.

AU - Gupta, Munish C.

AU - Gupta, Munish C.

AU - Hostin, Richard

AU - Deviren, Vedat

AU - Kebaish, Khaled

AU - Hart, Robert

AU - Burton, Douglas C.

AU - Line, Breton

AU - Bess, Shay

AU - Ames, Christopher P.

PY - 2014/12/1

Y1 - 2014/12/1

N2 - OBJECT: Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.METHODS: This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.RESULTS: Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8).CONCLUSIONS: Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.

AB - OBJECT: Improved understanding of rod fracture (RF) following adult spinal deformity (ASD) surgery could prove valuable for surgical planning, patient counseling, and implant design. The objective of this study was to prospectively assess the rates of and risk factors for RF following surgery for ASD.METHODS: This was a prospective, multicenter, consecutive series. Inclusion criteria were ASD, age > 18 years, ≥5 levels posterior instrumented fusion, baseline full-length standing spine radiographs, and either development of RF or full-length standing spine radiographs obtained at least 1 year after surgery that demonstrated lack of RF. ASD was defined as presence of at least one of the following: coronal Cobb angle ≥20°, sagittal vertical axis (SVA) ≥5 cm, pelvic tilt (PT) ≥25°, and thoracic kyphosis ≥60°.RESULTS: Of 287 patients who otherwise met inclusion criteria, 200 (70%) either demonstrated RF or had radiographic imaging obtained at a minimum of 1 year after surgery showing lack of RF. The patients' mean age was 54.8 ± 15.8 years; 81% were women; 10% were smokers; the mean body mass index (BMI) was 27.1 ± 6.5; the mean number of levels fused was 12.0 ± 3.8; and 50 patients (25%) had a pedicle subtraction osteotomy (PSO). The rod material was cobalt chromium (CC) in 53%, stainless steel (SS), in 26%, or titanium alloy (TA) in 21% of cases; the rod diameters were 5.5 mm (in 68% of cases), 6.0 mm (in 13%), or 6.35 mm (in 19%). RF occurred in 18 cases (9.0%) at a mean of 14.7 months (range 3-27 months); patients without RF had a mean follow-up of 19 months (range 12-24 months). Patients with RF were older (62.3 vs 54.1 years, p = 0.036), had greater BMI (30.6 vs 26.7, p = 0.019), had greater baseline sagittal malalignment (SVA 11.8 vs 5.0 cm, p = 0.001; PT 29.1° vs 21.9°, p = 0.016; and pelvic incidence [PI]-lumbar lordosis [LL] mismatch 29.6° vs 12.0°, p = 0.002), and had greater sagittal alignment correction following surgery (SVA reduction by 9.6 vs 2.8 cm, p < 0.001; and PI-LL mismatch reduction by 26.3° vs 10.9°, p = 0.003). RF occurred in 22.0% of patients with PSO (10 of the 11 fractures occurred adjacent to the PSO level), with rates ranging from 10.0% to 31.6% across centers. CC rods were used in 68% of PSO cases, including all with RF. Smoking, levels fused, and rod diameter did not differ significantly between patients with and without RF (p > 0.05). In cases including a PSO, the rate of RF was significantly higher with CC rods than with TA or SS rods (33% vs 0%, p = 0.010). On multivariate analysis, only PSO was associated with RF (p = 0.001, OR 5.76, 95% CI 2.01-15.8).CONCLUSIONS: Rod fracture occurred in 9.0% of ASD patients and in 22.0% of PSO patients with a minimum of 1-year follow-up. With further follow-up these rates would likely be even higher. There was a substantial range in the rate of RF with PSO across centers, suggesting potential variations in technique that warrant future investigation. Due to higher rates of RF with PSO, alternative instrumentation strategies should be considered for these cases.

KW - adult

KW - ASD = adult spinal deformity

KW - BMI = body mass index

KW - BMP-2 = recombinant human bone morphogenetic protein–2

KW - CCI = Charlson Comorbidity Index

KW - complication

KW - deformity

KW - instrumentation

KW - ISSG = International Spine Study Group

KW - LL = lumbar lordosis

KW - pedicle subtraction osteotomy

KW - PI = pelvic incidence

KW - PSO = pedicle subtraction osteotomy

KW - PT = pelvic tilt

KW - rod fracture

KW - sagittal imbalance

KW - spine

KW - surgery

KW - SVA = sagittal vertical axis

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U2 - 10.3171/2014.9.SPINE131176

DO - 10.3171/2014.9.SPINE131176

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JO - Journal of neurosurgery. Spine

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