Do radiographic parameters correlate with clinical outcomes in adolescent idiopathic scoliosis?

STUDY DESIGN

A radiographic assessment has been developed to include coronal, sagittal, and axial parameters.

OBJECTIVE

To determine the correlation of postoperative radiographic results and percentage postoperative radiographic improvement with patient clinical self-assessment.

SUMMARY OF BACKGROUND DATA

With the increasing interest in outcome studies, the authors wanted to determine whether Scoliosis Research Society clinical questionnaire results would correlate with objective radiographic improvement.

METHODS

INCLUSION CRITERIA

adolescent idiopathic scoliosis treated with anterior or posterior instrumentation, a solid fusion, minimum 2-year follow-up, and a completed postoperative Scoliosis Research Society questionnaire. Seventy-eight patients met the criteria. Measurements included in the radiographic score: Cobb angles of the coronal curve, C7 to the center sacral vertical line, apical translation, apical vertebral rotation, T1 rib angle, end-instrumented vertebrae angulation, angulation of the disc below the end-instrumented vertebra, and curve type. Sagittal measurements included T2-T12, T5-T12, T2-T5, T12-L2, and L1-S1.

RESULTS

The preoperative radiographic score of these 78 patients was mean 60.1 +/- 9.7 (range 41-88, maximum radiographic score, 100). The 2-year postoperative radiographic score was mean 83.8 +/- 8.8 (range, 65-100). The median Scoliosis Research Society questionnaire score was 98 +/- 12.3 (range, 58-116, maximum score, 125, showing that the patient is highly satisfied and asymptomatic). The postoperative radiographic score versus the questionnaire score showed a Spearman rank correlation of 0.04 (P = 0.68, little or no correlation throughout). Percentage improvement of the radiographic score versus the questionnaire score showed a Spearman rank correlation of 0.1 (P = 0.38, little or no correlation throughout).

CONCLUSION

In this initial group of patients, the radiographic assessment shows a significant improvement between preoperative and 2-year postoperative scores. However, little correlation between the radiographic assessment and the questionnaire scores was found in this adolescent population, suggesting that separate analyses of radiographic and clinical outcome data are required when evaluating results of postoperative scoliosis surgery.

Proximal kyphosis after posterior spinal fusion in patients with idiopathic scoliosis

STUDY DESIGN

For this retrospective study, preoperative and postoperative radiographs of posterior spinal fusions for idiopathic scoliosis were reviewed.

OBJECTIVES

To determine the prevalence and possible causes of proximal kyphosis after posterior spinal fusion for idiopathic scoliosis.

SUMMARY OF BACKGROUND DATA

Proximal kyphosis has been anecdotally noted after the insertion of Harrington rods and after use of the new posterior multisegmented hook/rod systems. In this study no attempt was made to determine whether this condition is painful or an adverse outcome for the patient or just a radiographic abnormality; however, it is suspected that this may be a problem in the long term, and it may be worthwhile to try to avoid it if predictive values can be ascertained.

METHODS

Patients with adolescent idiopathic scoliosis who had undergone posterior spinal fusion not extending above T3 with good-quality radiographs of the proximal thoracic spine and a minimum 2-year follow-up were studied. Of the 106 patients who underwent posterior spinal fusion from 1990 through 1994, 69 met the inclusion criteria. Abnormal kyphosis from T2 to the proximal level of the instrumented fusion was defined as kyphosis of more than 5 degrees above the summed normal angular segments.

RESULTS

Of 69 patients, 37 (54%) had normal proximal kyphosis, and 32 (46%) of the 69 were defined as having abnormal proximal kyphosis. In the 32 patients with abnormal proximal kyphosis, the measurement from T2 to the fusion was 10.3 degrees before surgery and 21.2 degrees after surgery. The normal group had kyphosis measuring 2.7 degrees from T2 to fusion before surgery and 5.3 degrees after surgery (P < 0.00001). Junctional kyphosis in the kyphosis group measured 6.5 degrees before surgery and 12.6 degrees after surgery, compared with normal kyphosis of 1.7 degrees and 2.6 degrees, respectively (P < 0.00001). When analyzing who would develop proximal kyphosis, preoperative one-level junctional kyphosis of more than 5 degrees above the proposed proximal instrumented vertebrae was shown to have the highest sensitivity (78%) and specificity (84%).

CONCLUSIONS

In this study, 32 (46%) of 69 patients had abnormal proximal kyphosis after undergoing posterior spinal fusion. A preoperative junctional kyphosis of more than 5 degrees above the proposed proximal instrumented vertebrae indicates that extending the fusion to a higher level in the thoracic spine would be beneficial in avoiding this problem.

Are there indications for partial rib resection in patients with adolescent idiopathic scoliosis treated with Cotrel-Dubousset instrumentation?

In adolescent idiopathic scoliosis the cosmetically unacceptable rib prominence is one of the main reasons patients seek treatment. Ninety-eight patients were reviewed with Cotrel-Dubousset (CD) instrumentation (average follow-up, 27 months; average preoperative curve, 53 degrees) and 27 patients with Harrington instrumentation and rib resection (average follow-up, 43 months; average preoperative curve, 52 degrees). Of the 98 patients who had CD instrumentation, 15 underwent concomitant rib resection. Of the 83 patients without rib resection, 71 (72%) were rated satisfactory and 12 unsatisfactory by cosmetic criteria based on residual rib deformity. These results were compared to those of 27 patients receiving Harrington rod instrumentation and rib resection, of whom 23 (85%) were rated as satisfactory. All 15 patients with CD and rib resection were rated satisfactory. The CD patients were then redivided into two groups (rib resection indicated or rib resection not indicated) as follows: the 12 unsatisfactory CD patients without rib resection (in whom a rib resection should have been done) were grouped with the 15 CD patients who underwent rib resection, for a total of 27 rib resections indicated, or 28%. This group was compared to the 71 satisfactory CD patients without rib resection (rib resection not indicated). Patients with a rib prominence of > 15 degrees preoperatively had or should have had a rib resection. Patients with a higher chance of needing rib resection included those with a curve severity greater than 60 degrees, curve flexibility less than 20%, a preoperative rib prominence > 10 degrees, or intraoperative curve correction of less than 50%.

Treatment of slipped capital femoral epiphysis. Spica-cast immobilization

Thirty-two patients (thirty-seven hips) who had a so-called acute-on-chronic or chronic slipped capital femoral epiphysis were treated with traction for relief of symptoms and then with immobilization in a spica cast for eight to sixteen weeks. The disappearance on radiographs of a metaphyseal juxtaphyseal radiolucency, rather than closure of the physis, was used as the criterion for removing the cast. In one (3 per cent) of the thirty-seven hips, the slip progressed; possibly this could have been prevented by keeping the cast on for a longer period of time. Narrowing of the cartilage space was seen after treatment in a cast in seven (19 per cent) of the thirty-seven hips. In five of these seven hips, this was true chondrolysis; in one, the diagnosis of chondrolysis had been apparent before treatment. Avascular necrosis did not develop as a result of treatment in any patient. Treatment in a spica cast should be considered as an alternative for patients who have an acute-on-chronic or chronic slipped capital femoral epiphysis.

A draping technique for spinal surgery using the Stagnara wake-up test

This draping procedure has been used at our hospital in more than 200 spinal procedures. The main advantage is that the surgeon has a direct view of the feet and can personally observe the results of the test. The draping procedure is simple, and it eliminates the chance of contamination when lifting the drapes. No disadvantages have been noted to date, and there have been no infections.