Biomechanical comparison of different anchors (foundations) for the pediatric dual growing rod technique

Mahar, Andrew; Bagheri, Ramin; Oka, Richard; Kostial, Patricia; Akbarnia, Behrooz A.

doi:10.1016/j.spinee.2007.10.031

Cited by 76 publications

(42 citation statements)

References 32 publications

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“…Several studies [1,3,11,23,24,27] have shown growing rods to be effective for achieving spinal length increase on the immature spine. Correction of the deformity will be achieved through only pure distractive forces between proximal and distal anchors in a traditional technique [17,26]. As anterior spinal growth continues, rotational deformity at the apical and intermediate segments will continue to progress and because there are no apical and intermediate anchors along the main curve, correction and control of the main deformity will be limited.…”

Section: Discussionmentioning

confidence: 99%

Apical and Intermediate Anchors Without Fusion Improve Cobb Angle and Thoracic Kyphosis in Early-onset Scoliosis

Enercan¹,

Kahraman²,

Ertürer³

et al. 2014

Clin Orthop Relat Res

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Background The main goal of treatment in early-onset scoliosis is to obtain and maintain curve correction while simultaneously preserving spinal, trunk, and lung growth. This study introduces a new surgical strategy, called the modified growing rod technique, which allows spinal growth and lung development while controlling the main deformity with apical and intermediate anchors without fusion. The use of intraoperative traction at the initial procedure enables spontaneous correction of the deformity and decreases the need for forceful correction maneuvers on the immature spine and prevents possible implant failures. This study seeks to evaluate (1) curve correction; (2) spinal length; (3) number of procedures performed; and (4) complications with the new approach. Description of Technique In the initial procedure, polyaxial pedicle screws were placed with a muscle-sparing technique. Rods were placed in situ after achieving correction with intraoperative skull-femoral traction. The most proximal and most distal screws were fixed and the rest of the screws were left with nonlocked set screws to allow vertical growth. The lengthening reoperations were performed every 6 months. Methods Between 2007 and 2011, we treated 19 patients surgically for early-onset scoliosis. Of those, 16 (29%) were treated with the modified growing rod technique by the senior author (AH); an additional three patients were treated using another technique that was being studied at the time by one of the coauthors (CO); those three were not included in this study. The 16 children included nine girls and seven boys (median, 5.5 years of age; range, 4-9 years), and all had progressive scoliosis (median, 64°; range, 38°-92°). All were available for followup at a minimum of 2 years (median, 4.5 years; range, 2-6 years). Results The initial curve Cobb angle of 64°(range, 38°-92°) improved to 21°(range, 4°-36°) and was maintained at 22°(range, 4°-36°) throughout followup. Preoperative thoracic kyphosis of 22°(range, 18°-46°) was maintained at 23°(range, 20°-39°) throughout followup without showing any substantial change. There was a 47 mm (range, 38-72 mm) increase in T1-S1 height throughout followup. The mean number of lengthening operations was 5.5 (range, 4-10). The mean T1-S1 length gain from the first lengthening was 1.18 cm (range, 1.03-2.24 cm) and decreased to 0.46 cm (range, 0,33-1.1 cm) after the fifth lengthening procedure (p = 0.009). The overall complication rate was 25% (four of 16 patients) and the procedural complication rate was 7% (seven of 102 procedures). We did not experience any rod breakages or other complications apart from two superficial wound infections managed without surgery during the treatment period. The only implant-related complications were loosening of two pedicle screws at the uppermost foundation in one patient.

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Section: Discussionmentioning

confidence: 99%

Apical and Intermediate Anchors Without Fusion Improve Cobb Angle and Thoracic Kyphosis in Early-onset Scoliosis

Enercan¹,

Kahraman²,

Ertürer³

et al. 2014

Clin Orthop Relat Res

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“…The implants of choice are placed at the previously selected anchor levels. Either hooks, claw-constructs using hooks or pedicle screws can be used as implants; the author prefers pedicle screws at both ends as previous studies have reported increased stability with their use and transverse connectors [13]. Only the facet joints at the anchor levels are excised and fusion performed; inter-and intraspinous ligaments and facet joint capsules at adjacent levels are preserved.…”

Section: Techniquementioning

confidence: 99%

“…Mahar et al [13] reported on the biomechanical comparison of various anchors and observed that screws at both anchor sites with cross-link constructs demonstrated the greatest load to failure, and all screw-only constructs were superior to constructs including hooks. These findings are concurrent with other reports regarding pedicle screw stability.…”

Section: Controversiesmentioning

confidence: 99%

Growing rod concepts: state of the art

Yazıcı

Olgun

2012

Eur Spine J

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Introduction Early-onset spinal deformities present multiple challenges to the surgeon. They may be rapidly progressive and unresponsive to conservative treatment, necessitating surgical intervention at an early age. Materials and methods This text attempts to provide a review of current literature and to summarize the authors' opinions. Results This paper attempts to concisely review available literature regarding the growing rod's inception, evolution, technique, results, and complications and answers some of the controversy still surrounding it. Conclusions The growing rod is one of the first, most evolved, most popular and one of the most heatedly discussed technique of fusionless spinal instrumentation.

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“…Pathologies like tumor, tuberculosis [22], congenital anomalies, and trauma including burst fractures [1,30] affect the immature and developing spine. To correct abnormalities such as those listed above, similar to the adult spine, surgical procedures are performed on the pediatric spine [16,23].…”

Section: Introductionmentioning

confidence: 99%

Validation efforts and flexibilities of an eight-year-old human juvenile lumbar spine using a three‐dimensional finite element model

Jebaseelan

Jebaraj

Yoganandan

et al. 2010

Med Biol Eng Comput

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The objective of this study was to develop a finite element model of the lumbar spinal column of an eight-year-old human spine and compare flexibilities under pure moments, adult, and pediatric loading with different material models. The geometry was extracted from computed tomography scans. The model included the cortical and cancellous bones, growth plates, ligaments, and discs. Adult, adolescent, and pediatric material models were used. Flexion (8 Nm), extension (6 Nm), lateral bending (6 Nm), and axial rotation (4 Nm) moments representing adult loads were applied to the three material models. Pediatric loading (0.5 Nm) was applied under these loadings to the eight-year-old spine using adult and pediatric material models. Flexibilities depended on spinal level, loading mode, and material model. Outputs incorporating the pediatric material model responded with increased flexibilities compared to the adult and adolescent material models, with one exception. This was true for the adult and pediatric loading conditions. While the sagittal and coronal bending responses were not considerably different between the adult and pediatric loadings, axial rotation responses were greater under the adult loading. This model may be used to determine intrinsic responses, such as stresses and strains, for improved characterizations of the juvenile spine behavior.

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Biomechanical comparison of different anchors (foundations) for the pediatric dual growing rod technique

Cited by 76 publications

References 32 publications

Apical and Intermediate Anchors Without Fusion Improve Cobb Angle and Thoracic Kyphosis in Early-onset Scoliosis

Apical and Intermediate Anchors Without Fusion Improve Cobb Angle and Thoracic Kyphosis in Early-onset Scoliosis

Growing rod concepts: state of the art

Validation efforts and flexibilities of an eight-year-old human juvenile lumbar spine using a three‐dimensional finite element model

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