Selection of the optimal distal fusion level in posterior instrumentation and fusion for thoracic hyperkyphosis: the sagittal stable vertebra concept.
ABSTRACT Retrospective study.
To determine the appropriate distal fusion level in posterior instrumentation and fusion for thoracic hyperkyphosis by investigating the relationship between the sagittal stable vertebra ([SSV]-the most proximal lumbar vertebral body touched by the vertical line from the posterior-superior corner of the sacrum), first lordotic vertebra (just caudal to the first lordotic disc), and selected lowest instrumented vertebra (LIV).
It has been recommended that the distal end vertebra and the first lordotic disc beyond the transitional zone distally be included in distal fusion for thoracic hyperkyphosis; however, we have seen distal junctional breakdown even when these rules have been followed.
Thirty-one patients (mean age: 18 years, range: 13-38) who underwent long posterior instrumentation and fusion for thoracic hyperkyphosis with a minimum 2-year follow-up were reviewed. Preoperative diagnoses included Scheuermann kyphosis (n = 29), post-traumatic kyphosis (n = 1), and postlaminectomy kyphosis (n = 1). According to the distal fusion level, patients were divided into 2 groups. Group I (n = 24): LIV included the SSV; group II (n = 7): the LIV was proximal to the SSV. Patients were evaluated using standing radiographs and chart review.
Preoperative mean thoracic kyphosis was 86.6 +/- 8.5 degrees and 53.0 +/- 10.4 degrees at final follow-up with a correction rate of 39%. Preoperative average sagittal balance was slightly negative (-0.24 +/- 3.8 cm), and became slightly more negative (-1.33 +/- 2.8 cm) by final follow-up. There were no statistical differences in thoracic kyphosis between the 2 groups. However, there was a statistically significant difference with group II having a more posterior translation of the center of the LIV from the posterior sacral vertical line before surgery and at final follow-up (P = 0.003). In group I, distal junctional problems developed in 2 of 24 (8%) patients and in group II, problems occurred in 5 of 7 (71%) patients (P < 0.05). Despite extending the fusion to the first lordotic vertebra, distal junctional problems developed in 3 of 8 (38%) patients.
The distal end of a fusion for thoracic hyperkyphosis should include the SSV. Levels that include the first lordotic vertebra but not the SSV are not always appropriate to prevent postoperative distal junctional kyphosis.
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ABSTRACT: This is a retrospective study of eight consecutive patients of mean age 19 (13-27) years with severe Scheuermann's kyphosis who underwent anterior and/or posterior fusion using the Cotrel-Dubousset (CD) instrumentation. In two an anterior release and fusion with rib grafts had been previously performed. The mean follow-up was 5 years. The preoperative hyperkyphosis averaged 86 degrees (71 degrees - 99 degrees), which was postoperatively 44 degrees (32 degrees - 58 degrees). The average loss of correction was 4.6 degrees (1 degrees - 12 degrees). The lumbar hyperlordosis spontaneously improved from -67 degrees to -48 degrees. Two patients, who had chronic back pain refractory to conservative treatment, improved considerably after surgery.International Orthopaedics 02/2001; 25(2):70-3. · 2.32 Impact Factor
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ABSTRACT: Thirty patients of a group of 39 patients with Scheuermann's kyphosis who underwent posterior spine fusion using large-diameter Harrington compression instrumentation were reviewed with a mean follow-up of 71.8 months. The mean curve before surgery was 71.5, and at follow-up, 37.7. The mean loss of correction at review was 6. This procedure was effective in adults with a fixed deformity as long as no anterior bony bridging existed. The authors believe that posterior Harrington instrumentation and spine fusion offer excellent correction of deformity at long-term follow-up without the added morbidity of a second procedure.Spine 06/1993; 18(6):685-91. · 2.16 Impact Factor
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ABSTRACT: A historic cohort study was conducted to investigate surgical correction and sagittal alignment in 33 patients with thoracic Scheuermann's disease. To evaluate kyphosis correction, correction loss, sagittal balance, and the effect of an anterior release. Currently, both posterior and anteroposterior techniques seem to produce impressive corrections for Scheuermann's disease. However, few reports have been made on sagittal malalignment after surgery. A cohort of 33 patients who had undergone surgery for their Scheuermann's kyphosis were reviewed: Group A: posterior technique (n = 16), Group B: anteroposterior technique (n = 17). Pre- and postoperative curve morphometry (Cobb, Ferguson, Voutsinas), balance (C7 plumb line), and Oswestry score were compared. The mean follow-up period was 4.5 +/- 2 years (range, 2-8.2 years). The mean preoperative kyphosis (Cobb) was 78.7 degrees +/- 8.9 degrees, and the mean postoperative kyphosis was 51.7 degrees +/- 10.3 degrees. At follow-up evaluation, the correction loss was 1,4 degrees +/- 3.9 degrees. There was no difference in curve morphometry, correction, sagittal balance, average age, and follow-up period between Groups A and B. One junctional kyphosis, in Group B, was noted. After surgery, all the patients were satisfied, and the Oswestry score showed significant improvement. No neurologic complications were observed. Good follow-up results included a 100% follow-up rate, adequate corrections, little correction loss, lower Oswestry scores, and a high satisfaction rate in both groups. The anteroposterior treatment did not influence the curve morphometry more than posterior fusion only. In reducing postoperative sagittal malalignment, the authors believe that surgical management should aim at a correction within the high normal kyphosis range of 40 degrees to 50 degrees, consequently providing good results and, particularly in flexible adolescents and young adults, minimizing the necessity for an anterior release.Spine 02/2002; 27(2):167-75. · 2.16 Impact Factor