Lowest Instrumented Vertebra Selection in AIS

Erickson, Mark; Baulesh, David M.

doi:10.1097/bpo.0b013e318202bfcd

Cited by 31 publications

(13 citation statements)

References 22 publications

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“…1 group, the difference was small and was not noticeable clinically as documented by the results There were some reports [15] concerning the changes in wedging of the adjacent disc or tilt of the last instrumented vertebra. A good correction of ADW and LIVT without loss of correction up to 10 years was achieved in our patients by means of the present method of instrumentation and the determination of the LIV.…”

Section: Discussionmentioning

confidence: 92%

Posterior correction of thoracic adolescent idiopathic scoliosis with pedicle screw instrumentation: results of 48 patients with minimal 10-year follow-up

2012

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Purpose Since early 1990s pedicle screws in thoracic spine have been used in posterior correction of adolescent idiopathic scoliosis (AIS). Long-term results are scarce. We report clinical, radiological and pulmonary function results of 48 consecutive patients with 10-year minimal follow-up. Methods Forty-eight consecutive patients (42 females, 6 males) with 41 Lenke 1 (lumbar modifier A = 19, B = 8, C = 14), 7 Lenke 2 (lumbar modifier A = 2, B = 4, C = 1) were operated for AIS from posterior with pedicle screw alone instrumentation. Risser stage at the time of operation was 0-3 in 24, more than 3 in 24 patients. Mean age was 15.3 years. The data were prospectively collected preoperatively, at 6 weeks, 2 years and 10 years postoperatively. Cobb angle, sagittal and coronal balance, distal adjacent disc angle and lowest fused vertebral tilt were documented at all time-points. Choice of fusion levels is described. Not every vertebra was instrumented with pedicle screws. The implant density was average one pedicle screw per vertebra or 50 %. Derotation and translation of apical vertebrae on the concave side were performed for correction. The overall outcome and the outcome of different curve types were analyzed statistically. Results Lowest instrumented vertebra (LIV) was distal end vertebra in two-thirds of the patients and was one below distal end vertebra in one-third of the patients. The main thoracic curve correction was 63 %, from 58°± 12°p reoperative to 21°± 9°at 6 weeks. The Cobb angle was 23°± 10°at 2 years and 26°± 10°at 10 years. The apical vertebral rotation improved 35 %, the non-instrumented lumbar curves improved 47 %, the distal adjacent disc angle decreased from 6°± 3°preoperatively to -2°± 4°p ostoperatively and the last instrumented vertebral tilt decreased from 23°± 8°preoperatively to 5°± 5°post-operatively. All these parameters remained stable up to 10-year follow-up. The scoliosis correction was not associated with any change in the preoperative thoracic kyphosis and lumbar lordosis. The % FVC remained unchanged with 74 ± 21 % preoperatively to 74 ± 11 % at 2 years and 75 ± 10 % at 10 years. The SRS-24 score was 93 ± 18 points at 2 years and 95 ± 22 points at 10 years. There were no neurological complications, no pedicle screw-related complications. Conclusion Posterior correction of thoracic AIS with pedicle screw instrumentation is safe and produces a longterm stable correction and high patient satisfaction. An implant density of 50 % is sufficient to achieve these results. LIV can be the distal end vertebra or one below the distal end vertebra depending on the position of the distal end vertebra to the centre sacral line. The preoperative pulmonary function does not change on long term.Keywords Adolescent idiopathic scoliosis Á Selective posterior correction with pedicle screw instrumentation Á Choice of fusion levels Á Long-term operative results Á Long-term pulmonary function

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Section: Discussionmentioning

confidence: 92%

Posterior correction of thoracic adolescent idiopathic scoliosis with pedicle screw instrumentation: results of 48 patients with minimal 10-year follow-up

2012

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“…2 The studies conducted by Lenke et al 6 suggest the use of bendings in the supine position, the same routine as that adopted by King et al 7 in their classic study on the selection of the arthrodesis site in thoracic scoliosis and other works. 8,9,10 In the authors' clinical practice, it was observed that performing lateralization exams with the patient standing, or with the patient in dorsal decubitus on a table without stabilization of the pelvis, inter-…”

Section: Discussionmentioning

confidence: 99%

Standardization of dynamic RX for preoperative planning in adolescent idiopathic scoliosis

et al. 2014

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OBJECTIVE: To compare X-rays usually performed in supine with lateralization with those in lateral decubitus with fulcrum at the apex of the primary curve caused by cushion, in order to monitor the achievement of improvement patterns of correction in preestablished deformities for the preoperative surgical planning. METHODS: Comparison of radiographic studies in the preoperative supine with lateralization and lateral decubitus with cushion performing fulcrum at the apex of the major curve in patients with adolescent idiopathic scoliosis. RESULTS: Curves varied in AP between 76° e 40° and were corrected in supine with lateralization to the average of 21° observing that when carried out with fulcrum with cushion in lateral decubitus the curves were corrected to 15° on average with higher discrepancy in values among the most rigid curves. CONCLUSIONS: It was verified that on flexible curves the cushions did not produce satisfactory corrections in primary curves. In more rigid curves and in collaborative patients, greater effectiveness on the correction of deformity in main curves was obtained with cushions producing local fulcrum for a better preoperative planning on correction of deformities.

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“…Although the spontaneous correction of the distal unfused lumbar curve after STF has been widely reported [ 1 , 13 – 20 ]; however, the impact of the spontaneous realignment of unfused segments on disc compensation remains to be quantified. To obtain an optimal balance outcome and prevent radiographical complications, such as the adding-on phenomenon, research has been conducted regarding the optimal LIV selection [ 8 , 21 ], prediction of SLCC [ 14 , 15 , 17 ] and related long-term outcome [ 6 , 22 ]. However, all these studies regarded the unfused distal segments as an ensemble.…”

Section: Introductionmentioning

confidence: 99%

Characteristics analysis of segmental and regional lumbar spontaneous compensation post thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis

Chen

Zhai

Zhou

et al. 2021

BMC Musculoskelet Disord

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Objective To explore the characteristics of compensation of unfused lumbar region post thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis. Background Preserving lumbar mobility in the compensation is significant in controlling pain and maintaining its functions. The spontaneous correction of the distal unfused lumbar curve after STF has been widely reported, but previous study has not concentrated on the characteristics of compensation of unfused lumbar region post thoracic fusion. Method A total of 51 Lenke 1 and2 AIS patients were included, whose lowest instrumented vertebrae was L1 from January 2013 to December 2019. For further analysis, demographic data and coronal radiographic films were collected before surgery, at immediate erect postoperatively and final follow-up. The wedge angles of each unfused distal lumbar segments were measured, and the variations in each disc segment were calculated at the immediate postoperative review and final follow-up. Meanwhile, the unfused lumbar curve was divided into upper and lower parts, and we calculated their curve angles and compensations. Results The current study enrolled 41 females (80.4%) and 10 males (19.6%). Thirty-six patients were Lenke type 1, while 15 patients were Lenke type 2. The average main thoracic Cobb angle and thoracolumbar/lumbar Cobb angle were 44.1 ± 7.7°and 24.1 ± 9.3°, preoperatively. At the final follow-up, the disc wedge angle variation of L1/2, L2/3, L3/4, L4/5 and L5/S1 was 3.84 ± 5.96°, 3.09 ± 4.54°, 2.30 ± 4.53°, − 0.12 ± 3.89° and − 1.36 ± 2.80°, respectively. The compensation of upper and lower coronal lumbar curves at final follow-up were 9.22 ± 10.39° and − 1.49 ± 5.14°, respectively. Conclusion When choosing L1 as the lowest instrumented vertebrae, the distal unfused lumbar segments’ compensation showed a decreasing trend from the proximal end to the distal end. The adjacent L1/2 and L2/3 discs significantly contributed to this compensation.

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Lowest Instrumented Vertebra Selection in AIS

Cited by 31 publications

References 22 publications

Posterior correction of thoracic adolescent idiopathic scoliosis with pedicle screw instrumentation: results of 48 patients with minimal 10-year follow-up

Posterior correction of thoracic adolescent idiopathic scoliosis with pedicle screw instrumentation: results of 48 patients with minimal 10-year follow-up

Standardization of dynamic RX for preoperative planning in adolescent idiopathic scoliosis

Characteristics analysis of segmental and regional lumbar spontaneous compensation post thoracic fusion in Lenke 1 and 2 adolescent idiopathic scoliosis

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