The Crankshaft Phenomenon

Dubousset, Jean; Herring, John A.; Shufflebarger, Harry

doi:10.1097/01241398-198909010-00008

Cited by 350 publications

(140 citation statements)

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“…However, consensus appears to exist in the necessity to restore a global spinal alignment in the sagittal plane while correcting the thoracic hypokyphosis [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Reciprocal sagittal alignment changes after posterior fusion in the setting of adolescent idiopathic scoliosis

et al. 2012

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Purpose Surgical adolescent idiopathic scoliosis (AIS) management can be associated with loss of thoracic kyphosis and a secondary loss of lumbar lordosis leading to iatrogenic flatback. Such conditions are associated with poorer clinical outcomes during adulthood. The aim of this study was to evaluate sagittal plane reciprocal changes after posterior spinal fusion in the setting of AIS. Methods Thirty consecutive adolescents (mean age 14.6 years) with AIS Lenke 1, 2 or 3 were included in this retrospective study with 2 year follow-up. Full-spine standing coronal and lateral radiographs were obtained preoperatively, at 3 and 24 months postoperatively. Coronal Cobb angle, thoracic kyphosis (TK) and lumbar lordosis (LL) were measured. Surgical procedure was similar in all the cases, with use of pedicular screws between T11 and the lowest instrumented vertebra (CL2), sublaminar hooks applied in compression at the upper thoracic level and sub-laminar bands and clamps in the concavity of the deformity. Statistical analysis was done using t test and Pearson correlation coefficient. Results Between preoperative and last follow-up evaluations a significant reduction of Cobb angle was observed (53.6°vs. 17.2°, p \ 0.001). A significant improvement of the instrumented thoracic kyphosis, TK (19.7°vs. 26.2°, p \ 0.005) was noted, without difference between 3 and 24 months postoperatively. An improvement in lumbar lordosis, LL (43.9°vs. 47.3°, p = 0.009) was also noted but occurred after the third postoperative month. A significant correlation was found between TK correction and improvement of LL (R = 0.382, p = 0.037), without correlation between these reciprocal changes and the amount of coronal correction. Conclusion Results from this study reveal that sagittal reciprocal changes occur after posterior fusion when TK is restored. These changes are visible after 3 months postoperatively, corresponding to a progressive adaptation of patient posture to the surgically induced alignment. These changes are not correlated with coronal plane correction of the deformity. In the setting of AIS, TK restoration is a critical goal and permits favorable postural adaptation. Further studies will include pelvic parameters and clinical scores in order to evaluate the impact of the noted reciprocal changes.

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“…However, consensus appears to exist in the necessity to restore a global spinal alignment in the sagittal plane while correcting the thoracic hypokyphosis [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Reciprocal sagittal alignment changes after posterior fusion in the setting of adolescent idiopathic scoliosis

et al. 2012

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“…The concomitant control of complex spinal deformities by force transmission from the ribs to the spine and pelvis [2][3][4] stimulates surgeons to expand the indications beyond the primary scope to early onset deformities of idiopathic, neuromuscular and syndromic origin [5,6]. The growth-promoting lengthening strategy and the polyaxial anchor points may overcome post-fusion issues such as short and stiff trunk, small thorax, poor pulmonary function and crankshaft phenomenon [4,7,8]. However, VEPTR's safety and efficacy remains still to be shown for non-congenital deformities.…”

Section: Introductionmentioning

confidence: 99%

Efficacy and safety of VEPTR instrumentation for progressive spine deformities in young children without rib fusions

2009

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This retrospective study analyses 23 children treated with vertical expandable prosthetic titanium rib (VEPTR) for correction of non-congenital early onset spine deformities. After the index procedure (IP), the device was lengthened at 6-month intervals. The average (av) age at the time of IP was 6.5 years (1.11-10.5). The av follow-up time was 3.6 years (2-5.8). Diagnosis included 1 early onset idiopathic scoliosis, 11 neuromuscular, 2 post-thoracotomy scoliosis, 1 Sprengel deformity, 2 hyperkyphosis, 1 myopathy and 5 syndromic. Surgeries (187) included 23 IPs, av 6.5 (4-10) device expansions per patient (149) and 15 unplanned surgeries. 23 complications (0.13 per surgery) included 10 skin sloughs, 5 implant dislocations, 2 rod breakages and 6 infections. Coronal Cobb angle was av 68°(11°-111°), at follow-up av 54°(0°-105°). Pelvic obliquity was av 33°( 13°-60°), at follow-up av 16°(0°-42°). T1 tilt was av 29°( 5°-84°), two remained unchanged, the remainder improved 10°-68°. Sagittal plane: All but two had stable profiles, two hyperkyphosis of 110°/124°improved to 56°/86°. Space available for lung ratio was less than 90% in ten before the IP, improved in nine and deteriorated in one. Originally designed for thoracic insufficiency syndromes related to rib and vertebral anomalies, VEPTR proved to be a valuable alternative to dual growing rods for non-congenital early onset spine deformities. The complication rate was lower, the control of the sagittal plane and the pelvic obliquity was as good, but the correction of the coronal plane deformity was less than growing rods. However, VEPTR's spine-sparing approach might provoke less spontaneous spinal fusion and ease the final correction at maturity.

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Section: Introductionmentioning

confidence: 99%

“…Blakemore et al [1] and Morin [15] introduced segmental spinal instrumentation systems (Cotrel-Dubousset, Isola, etc) for severe spinal deformities in young children. However, in all of these procedures, spontaneous bony fusion can occur before the patients reach maturity [7,14], also causing posterior ankylosis and crankshaft [5].Abstract "Spinal instrumentation without fusion" techniques, which do not interfere with spinal growth, have been used extensively in the treatment of progressive spinal scoliosis in very young children. Due to subperiosteal exposure, the process of spinal instrumentation may induce spontaneous bony fusion.…”

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confidence: 99%

Inhibition of spinal fusion by use of a tissue ingrowth inhibitor

Zou

Egund

et al. 2004

European Spine Journal

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IntroductionBecause of the associated disturbance of spinal growth, surgery for progressive spinal deformities in very young children is a challenging task. Most foregoing studies report having used a "growing spinal instrumentation without fusion" technique in order to avoid interference with spinal growth. Harrington first described the procedure, which used a Harrington rod [10]. The "Luque trolley" technique of segmental spinal instrumentation without fusion has been used with some success [13,14,18]. Blakemore et al [1] and Morin [15] introduced segmental spinal instrumentation systems (Cotrel-Dubousset, Isola, etc) for severe spinal deformities in young children. However, in all of these procedures, spontaneous bony fusion can occur before the patients reach maturity [7,14], also causing posterior ankylosis and crankshaft [5].Abstract "Spinal instrumentation without fusion" techniques, which do not interfere with spinal growth, have been used extensively in the treatment of progressive spinal scoliosis in very young children. Due to subperiosteal exposure, the process of spinal instrumentation may induce spontaneous bony fusion. Instrumentation and surgical techniques have been modified in order to prevent spontaneous posterior fusion from occurring in children. An absorbable ADCON-L gel has been shown to inhibit scar and epidural adhesions following spinal surgeries. However, little is known about its influence on spinal fusion. In the present study, a single-level intertransverse arthrodesis at L4-5 on both sides was performed on each of nine pigs. Each side was randomly designed to receive autogenous bone graft with or without ADCON-L gel. The animals were followed for 10 weeks postoperatively. A fusion rate of 78% (7/9) was obtained in the autograft treatment by plain X-ray and CT evaluation, while the autograft/ADCON-L treatment yielded a 0% (0/9) fusion rate (p=0.001). Histomorphometric evaluation revealed that the addition of ADCON-L gel to bone graft decreased bone and bone marrow formation and significantly increased fibrous tissue formation. No statistical difference between the two treatments was found in cartilage, bone surface density, osteoid surfaces or osteoclast-covered surfaces in any zone. We conclude that ADCON-L gel mixed into autogenous bone graft can delay or decrease bone formation at spinal arthrodesis sites, thus influencing the extent of spinal fusion. This accords with our hypothesis that the use of ADCON-L gel can prevent not only the occurrence of spontaneous fusion in very young scoliosis patients after instrumentation without fusion, but also re-ossification of a decompressed spinal canal.

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The Crankshaft Phenomenon

Cited by 350 publications

References 0 publications

Reciprocal sagittal alignment changes after posterior fusion in the setting of adolescent idiopathic scoliosis

Reciprocal sagittal alignment changes after posterior fusion in the setting of adolescent idiopathic scoliosis

Efficacy and safety of VEPTR instrumentation for progressive spine deformities in young children without rib fusions

Inhibition of spinal fusion by use of a tissue ingrowth inhibitor

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