[Effect of modified unilaterally-open expansive laminoplasty using bridge grafting and restructing posterior ligamentous complex methods on axial symptoms and cervical curvature change].

OBJECTIVE

To explore if the modified unilaterally-open expansive laminoplasty using bridge grafting and reconstructing posterior ligamentous complex methods is effective in preventing persisting axial symptoms, restriction of neck motion, and loss of cervical curvature.

METHODS

From June 2000 to October 2005, 138 patients with cervical spondylotic myelopathy underwent this procedure. Of them, 78 who were followed for more than 2 years (group A) were included in this study. Another 69 patients who underwent conventional unilaterally open-door laminoplasty served as controls (group B). The JOA scores and the incidence of newly developed or deteriorated axial symptoms were recorded. Preoperative and postoperative ranges of neck motion were measured on lateral flexion and extension radiographs. Preoperative and postoperative cervical curvature indices were calculated according to Ishihara's method.

RESULTS

The patients of group A were followed 24-44 months (mean 33 months), and the patients of group B were followed 24-53 months(mean 35 months). The operative time was 114+/-20 min in group A and 70+/-25 min in group B, showing statistically significant difference (P<0.05). The operative blood loss was 280+/-72 ml in group A and 210+/-80 ml in group B (P>0.05). According to JOA scoring, the average recovery rates were 67.0%+/-17.3% in group A and 65.0%+/-21.4% in group B (P>0.05). Postoperative development or deterioration of axial symptoms occurred in 12% of patients in group A and 51% of patients in group B, showing statistically significant difference (P<0. 05). Postoperative range of neck motion was 88.0%+/-10.1% of the preoperative one in group A and 64.0%+/-16.3% in group B (P< 0.05). There was no significant difference between preoperative (15.3+/-8.2) and postoperative (13.5+/-9.3) cervical curvature index in group A, whereas the mean value of postoperative index (11.1+/-5.7) was significantly smaller than that of preoperative one (17.2+/-13.5) in group B (P<0.05).

CONCLUSION

This new procedure was less invasive to the posterior extensor mechanism than the conventional unilaterally-open laminoplasty and was effective in preventing postoperative morbidities.