Notch Sensitivity of Titanium Alloy, Commercially Pure Titanium, and Stainless Steel Spinal Implants

Dick, Jeffrey C.; Bourgeault, Craig A.

doi:10.1097/00007632-200108010-00008

Cited by 101 publications

(56 citation statements)

References 15 publications

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“…In addition, fixation rods in the setting of PSO are often bent to angles of 20° to 60° and may be notched by the bending instruments. Previous studies have demonstrated that CC and TA have greater fatigue life than SS, 27,45 that TA is very notch sensitive, 14,27 and that bending rods lowers their performance. 5,21,25,30 Compared with TA and SS, CC has the greatest elastic modulus and displays the greatest ultimate stress.…”

Section: Discussionmentioning

confidence: 99%

“…Although data thus far seem to indicate that selected adults with spinal deformity do have significant potential for improvement with surgical treatment, overall complication rates remain high and represent areas for continued improvement 7,8,32,[39][40][41][42][43] Despite great advances, an important source of complications and patient morbidity remains the inherent limitations of the durability of spinal implants. 1,3,4,6,[13][14][15][16][17][19][20][21]23,[25][26][27]30,32,33,38,[44][45][46][47]50,51 Although development of rod fracture may have significant consequences for patients, including pain, loss of deformity correction, and the need for revision surgery, the literature regarding rod fracture remains relatively limited. 1,4,9,11,15,19,23,29,38,49,51,52 Previous reports discussing rod fracture have...…”

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confidence: 99%

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

Smith

Shaffrey

Klineberg

et al. 2014

SPI

214

174

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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.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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

Smith

Shaffrey

Klineberg

et al. 2014

SPI

214

174

View full text Add to dashboard Cite

show abstract

“…We used titanium rods as replacements in all cases of rod breakages. Several investigators have noted that titanium rods have the advantages of magnetic resonance imaging compatibility and increased rigidity, but are prone to microfracture propagation and are notch-sensitive in bending 6,16) . Stainless steel rods are thus used in most patients, except for those with infections or tumors.…”

Section: Discussionmentioning

confidence: 99%

Clinical Outcomes and Complications after Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance Patients : A Long-Term Follow-Up Data

Hyun

Rhim

2010

J Korean Neurosurg Soc

145

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J Korean Neurosurg Soc 47 : 95-101, 2010Objective : Clinical, radiographic, and outcomes assessments, focusing on complications, were performed in patients who underwent pedicle subtraction osteotomy (PSO) to assess correction effectiveness, fusion stability, procedural safety, neurological outcomes, complication rates, and overall patient outcomes. Methods : We analyzed data obtained from 13 consecutive PSO-treated patients presenting with fixed sagittal imbalances from 1999 to 2006. A single spine surgeon performed all operations. The median follow-up period was 73 months (range 41-114 months). Events during perioperative course and complications were closely monitored and carefully reviewed. Radiographs were obtained and measurements were done before surgery, immediately after surgery, and at the most recent follow-up examinations. Clinical outcomes were assessed using the Oswestry Disability Index and subjective satisfaction evaluation. Results : Following surgery, lumbar lordosis increased from -14.1°± 20.5°to -46.3°± 12.8°(p < 0.0001), and the C7 plumb line improved from 115 ± 43 mm to 32 ± 38 mm (p < 0.0001). There were 16 surgery-related complications in 8 patients; 3 intraoperative, 3 perioperative, and 10 lateonset postoperative. The prevalence of proximal junctional kyphosis (PJK) was 23% (3 of 13 patients). However, clinical outcomes were not adversely affected by PJK. Intraoperative blood loss averaged 2,984 mL. The C7 plumb line values and postoperative complications were closely correlated with clinical results. Conclusion : Intraoperative or postoperative complications are relatively common following PSO. Most late-onset complications in PSO patients were related to PJK and instrumentation failure. Correcting the C7 plumb line value with minimal operative complications seemed to lead to better clinical results. 10.3340/jkns.2010.47.2.95

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“…Jutte et al [16] reported a 0.9% incidence of rod failure in 105 lumbar or lumbosacral fusions, and in most other reports, rod fractures occurred after posterior lumbar fusion surgery. Intraoperative rod contouring and corrective procedures using reduction devices are generally thought to be risk factors for the failure of spinal constructs, particularly with pure titanium or titanium alloy implants because of their notch sensitivity [10,18,19]. One reason that no rod fracture was observed in our cohort may be that we tried as much as possible to avoid bending the rod, taking maximal advantage of the polyaxial screw and offset connecting device (Fig.…”

Section: The Characteristics As For Cervical Instrumentation Failurementioning

confidence: 99%

Mechanical implant failure in posterior cervical spine fusion

et al. 2011

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Purpose The aim of this study was to determine whether the recent refinement and downsizing of the implants for posterior cervical fusion increase the occurrence of implant failure. Methods One hundred forty-two consecutive cases of cervical fusion, using either cannulated Magerl screws or a multiaxial pedicle screw-rod system, were reviewed retrospectively after an average follow-up period of more than 3 years, and the rate and characteristics of the failure of these implants were evaluated. Results Implant failure occurred in six (4.2%) patients: five with rheumatoid arthritis and one with athetoid cerebral palsy. Occipital plate fracture occurred in two patients, Magerl screw breakage in one patient, cervical pedicle screw fracture in two patients, and disassembly of the pedicle screw and rod in two patients (one with an occipital plate fracture). There was no rod fracture. The implant failures were asymptomatic, except in one patient. Disassembly of the pedicle screw and rod was observed immediately after another surgical procedure under general anesthesia in two patients. Conclusions The failure rate of 4.2% was similar to the rates reported in the literature for posterior lumbar spinal fusion, confirming the reliability of the recent cervical screw-rod system.

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Notch Sensitivity of Titanium Alloy, Commercially Pure Titanium, and Stainless Steel Spinal Implants

Abstract: Caution is recommended when bending TI or CP rods, or placing a connector and removing it when using CP rods in situations in which fatigue failure is a concern.

Cited by 101 publications

References 15 publications

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

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

Clinical Outcomes and Complications after Pedicle Subtraction Osteotomy for Fixed Sagittal Imbalance Patients : A Long-Term Follow-Up Data

Mechanical implant failure in posterior cervical spine fusion

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