Browsing by Author "Demakakos, Jason"
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Item Open Access Assessment of symptomatic rod fracture after posterior instrumented fusion for adult spinal deformity.(Neurosurgery, 2012-10) Smith, Justin S; Shaffrey, Christopher I; Ames, Christopher P; Demakakos, Jason; Fu, Kai-Ming G; Keshavarzi, Sassan; Li, Carol MY; Deviren, Vedat; Schwab, Frank J; Lafage, Virginie; Bess, Shay; International Spine Study GroupBackground
Improved understanding of rod fracture (RF) in adult spinal deformity could be valuable for implant design, surgical planning, and patient counseling.Objective
To evaluate symptomatic RF after posterior instrumented fusion for adult spinal deformity.Methods
A multicenter, retrospective review of RF in adult spinal deformity was performed. Inclusion criteria were spinal deformity, age older than 18 years, and more than 5 levels posterior instrumented fusion. Rod failures were divided into early (≤12 months) and late (>12 months).Results
Of 442 patients, 6.8% had symptomatic RF. RF rates were 8.6% for titanium alloy, 7.4% for stainless steel, and 2.7% for cobalt chromium. RF incidence after pedicle subtraction osteotomy (PSO) was 15.8%. Among patients with a PSO and RF, 89% had RF at or adjacent to the PSO. Mean time to early RF (63%) was 6.4 months (range, 2-12 months). Mean time to late RF (37%) was 31.8 months (range, 14-73 months). The majority of RFs after PSO (71%) were early (mean, 10 months). Among RF cases, mean sagittal vertical axis improved from preoperative (163 mm) to postoperative (76.9 mm) measures (P<.001); however, 16 had postoperative malalignment (sagittal vertical axis>50 mm; mean, 109 mm).Conclusion
Symptomatic RF occurred in 6.8% of adult spinal deformity cases and in 15.8% of PSO patients. The rate of RF was lower with cobalt chromium than with titanium alloy or stainless steel. Early failure was most common after PSO and favored the PSO site, suggesting that RF may be caused by stress at the PSO site. Postoperative sagittal malalignment may increase the risk of RF.Item Open Access The comprehensive anatomical spinal osteotomy classification.(Neurosurgery, 2014-01) Schwab, Frank; Blondel, Benjamin; Chay, Edward; Demakakos, Jason; Lenke, Lawrence; Tropiano, Patrick; Ames, Christopher; Smith, Justin S; Shaffrey, Christopher I; Glassman, Steven; Farcy, Jean-Pierre; Lafage, VirginieBackground
Global sagittal malalignment is significantly correlated with health-related quality-of-life scores in the setting of spinal deformity. In order to address rigid deformity patterns, the use of spinal osteotomies has seen a substantial increase. Unfortunately, variations of established techniques and hybrid combinations of osteotomies have made comparisons of outcomes difficult.Objective
To propose a classification system of anatomically-based spinal osteotomies and provide a common language among spine specialists.Methods
The proposed classification system is based on 6 anatomic grades of resection (1 through 6) corresponding to the extent of bone resection and increasing degree of destabilizing potential. In addition, a surgical approach modifier is added (posterior approach or combined anterior and posterior approaches). Reliability of the classification system was evaluated by an analysis of 16 clinical cases, rated 2 times by 8 different readers, and calculation of Fleiss kappa coefficients.Results
Intraobserver reliability was classified as "almost perfect"; Fleiss kappa coefficient averaged 0.96 (range, 0.92-1.0) for resection type and 0.90 (0.71-1.0) for the approach modifier. Results from the interobserver reliability for the classification were 0.96 for resection type and 0.88 for the approach modifier.Conclusion
This proposed anatomically based classification system provides a consistent description of the various osteotomies performed in spinal deformity correction surgery. The reliability study confirmed that the classification is simple and consistent. Further development of its use will provide a common frame for osteotomy assessment and permit comparative analysis of different treatments.Item Open Access The comprehensive anatomical spinal osteotomy classification.(Neurosurgery, 2015-03) Schwab, Frank; Blondel, Benjamin; Chay, Edward; Demakakos, Jason; Lenke, Lawrence; Tropiano, Patrick; Ames, Christopher; Smith, Justin S; Shaffrey, Christopher I; Glassman, Steven; Farcy, Jean-Pierre; Lafage, VirginieBackground
Global sagittal malalignment is significantly correlated with health-related quality-of-life scores in the setting of spinal deformity. In order to address rigid deformity patterns, the use of spinal osteotomies has seen a substantial increase. Unfortunately, variations of established techniques and hybrid combinations of osteotomies have made comparisons of outcomes difficult.Objective
To propose a classification system of anatomically-based spinal osteotomies and provide a common language among spine specialists.Methods
The proposed classification system is based on 6 anatomic grades of resection (1 through 6) corresponding to the extent of bone resection and increasing degree of destabilizing potential. In addition, a surgical approach modifier is added (posterior approach or combined anterior and posterior approaches). Reliability of the classification system was evaluated by an analysis of 16 clinical cases, rated 2 times by 8 different readers, and calculation of Fleiss kappa coefficients.Results
Intraobserver reliability was classified as 'almost perfect'; Fleiss kappa coefficient averaged 0.96 (range, 0.92-1.0) for resection type and 0.90 (0.71-1.0) for the approach modifier. Results from the interobserver reliability for the classification were 0.96 for resection type and 0.88 for the approach modifier.Conclusion
This proposed anatomically based classification system provides a consistent description of the various osteotomies performed in spinal deformity correction surgery. The reliability study confirmed that the classification is simple and consistent. Further development of its use will provide a common frame for osteotomy assessment and permit comparative analysis of different treatments.