Study Design: A prospective radiographic study. Objectives: To analyze the relationship between craniocervical sagittal balance and thoracic inlet (TI) alignment and to present the parameters that would help predict physiological lordosis of the cervical spine. Summary of Background Data: The physiological cervical lordosis (CL) and related factors has not been clearly defined yet. No studies have reported correlations between TI alignment and sagittal balance of the cervical spine. Methods: Cervical spine lateral radiograph of 77 asymptomatic adult volunteers (aged between 21 and 50 y) were taken to analyze the following parameters. (1) Thoracic inlet parameters: thoracic inlet angle (TIA), T1 slope, neck tilting (NT); (2) cervical spine parameters: C0-2 angle, C2-7 angle, % ratio of (C0-2/C0-7 angle), (C2-7/C0-7 angle), and cervical tilting; (3) cranial parameters: C0 angle, cranial offset, and cranial tilting. Statistical analysis was performed using the Pearson correlation coefficients and multiple regression analysis. Results: The mean TIA, T1 slope, NT were 69.5, 25.7, and 43.7, respectively. The mean C0-2 angle, C2-7 angle, C0 angle, cranial offset, cervical tilting, and cranial tilting were −22.4 degrees, −9.9 degrees, −9.3 degrees, 20.9 mm, 18 degrees, and 7.7 degrees, respectively. The ratio of C0-2:C2-7 angle was maintained as 77:23% and cervical tilting:cranial tilting was 70.2:29.8%. A significant correlation was found between TIA and T1 slope (r=0.694), T1 slope and C2-7 angle (r=−0.624), C2-7 angle and C0-2 angle (r=−0.547), C0-2 angle and cranial offset (r=−0.406). Conclusions: The thoracic inlet alignment had significant correlations with craniocervical sagittal balance. To preserve physiological NT around 44 degrees, large TIA increased T1 slope and CL and vice versa. TIA and T1 slope could be used as parameters to predict physiological alignment of the cervical spine. The results of this study may serve as baseline data for the evaluation of sagittal balance or planning of a fusion angle in the cervical spine.

Study Design. A retrospective evaluation of 28 patients with recurrent lumbar disc herniation. Objectives. To analyze the outcome of the revisions (repeat discectomy), the risk factors of recurrent disc herniation, and the factors that influenced the outcomes of repeat discectomy. Summary of Background Data. Recurrent herniation following disc excision has been reported in 5–11% of patients. There have been many studies on recurrent disc herniation, but these studies have analyzed mixed patient populations. Methods. Recurrent lumbar disc herniation was defined as disc herniation at the same level, regardless of ipsilateral or contralateral herniation, with a pain-free interval greater than 6 months. Eight women and 20 men were studied. The levels of disc herniation were L4–L5 (19 cases) and L5–S1 (9 cases). Gadolinium-enhanced magnetic resonance imaging was performed in all patients. Revision surgery was performed in all patients by using conventional open discectomy. The pain-free interval, side and degree of herniation, operation time, duration of hospital stay, and clinical improvement rate were recorded. Results. The mean pain-free interval was 60.8 months. There were 21 cases of ipsilateral herniation and 7 cases of contralateral herniation. The degrees of herniation in revision were protrusion (14 cases), subligamentous extrusion (3 cases), transligamentous extrusion (8 cases), and sequestration (3 cases). The degrees of herniation in the previous discectomy were protrusion (17 cases), subligamentous extrusion (10 cases), and transligamentous extrusion (1 case). The length of surgery was significantly different (P = 0.003) between the revision surgery and the previous discectomy. There were no significant differences between revision and previous surgery in terms of hospital stay or clinical improvement rates. Age, gender, smoking, professions, traumatic events, level and degree of herniation, and pain-free interval did not affect the clinical outcomes. Conclusion. Conventional open discectomy as a revision surgery for recurrent lumbar disc herniation showed satisfactory results that were comparable with those of primary discectomy. Based on the results of this study, repeat discectomy can be recommended for the management of recurrent lumbar disc herniation.

A prospective study. To assess the significance of chin-brow vertical angle in planning and evaluating the correction of kyphotic deformity with ankylosis of the cervical spine in ankylosing spondylitis patients. Accurate assessment and measurement of spinal kyphotic deformity is required when planning treatment and assessing its results. Thirty-four ankylosing spondylitis patients with cervical ankylosis who had undergone pedicle subtraction extension osteotomy for correction of kyphotic deformity were studied. Radiographic assessment for sagittal balance was performed by measuring thoracic kyphosis, lumbar lordosis, the distance between the vertical line on the anterosuperior point of T1 and that of S1, and sacral inclination. Chin-brow vertical angle was measured on the clinical photos of the patients. Clinical outcomes were assessed by a questionnaire. The preoperative and postoperative chin-brow vertical angles were 35.5 degrees and 1.8 degrees, respectively. Final follow-up radiographs showed an increase in lumbar lordosis from 5.5 degrees to 43.2 degrees (an increase of 37.7 degrees ), and thoracic kyphosis remained stable from 50.4 degrees to 50.2 degrees. Sagittal imbalance significantly improved from 101.5 mm to 12.7 mm. The decreased chin-brow vertical angle correlated negatively with the correction angle. The patients with a chin-brow vertical angle of less than -10 degrees had significantly low scores on horizontal gaze. Chin-brow vertical angle was an objective index for evaluating horizontal gaze. Based on the results of this study, measurement of chin-brow vertical angle is recommended for planning correction of kyphosis and accurate evaluation of treatment outcome.

A prospective study was performed in 45 patients with ankylosing spondylitis. To assess the outcomes of decancellation pedicle subtraction extension osteotomy in ankylosing spondylitis patients with severe fixed kyphotic deformity. There have been several studies regarding correction of kyphotic deformity in ankylosing spondylitis. However, most of them concern surgical technique. There have been no reports concerning clinical results of decancellation pedicle subtraction osteotomy in ankylosing spondylitis. The kyphotic deformity was corrected by a one-stage pedicle subtraction extension osteotomy. Radiographic assessment for sagittal balance was performed by measuring thoracic kyphosis, lumbar lordosis, distance between the vertical line on anterosuperior point of T1 and that of S1, and sacral inclination. Chin brow–vertical angle was measured on the preoperative and postoperative clinical photograph of patients. Clinical outcomes were assessed by questionnaire measuring changes in physical function, indoor activity, outdoor activity, psychosocial activity, pain, and patient satisfaction with surgery. Final follow-up radiograph showed an increase in lumbar lordosis from 10° to 44° (an increase of 34°), whereas thoracic kyphosis remained stable from 50° to 54°. Sagittal imbalance significantly improved from 94 to 8 mm, whereas sacral inclination increased from 8° to 24°. The chin brow–vertical angle was 32.0° before surgery and 0.9° after surgery. Satisfactory clinical outcome was achieved; however, clinical improvements did not correlate with changes in radiologic measurements. Most of the patients maintained good correction and had good clinical results. Based on the results of this study, pedicle subtraction extension osteotomy is effective for correction of kyphotic deformity in ankylosing spondylitis.

This prospective randomized study compared 3 fusion methods: posterolateral fusion (PLF), posterior lumbar interbody fusion (PLIF), and PLIF combined with PLF (PLF+PLIF). To compare the outcomes of the 3 fusion methods and find a useful fusion method. Many studies have shown clinical results, advantages, and postoperative complications of each fusion method, but few have compared the 3 fusion methods prospectively. A total of 167 patients who underwent 1 or 2-level fusion surgery because of degenerative lumbar disease from January 1996 to September 2000 were studied. Minimum follow-up was 3 years. The patients were randomized into 1 of 3 treatment groups: group 1 (PLF; n = 62); group 2 (PLIF; n = 57); and group 3 (PLF+PLIF; n = 48). A visual analog scale, the Oswestry Disability Questionnaire, and Kirkaldy-Willis criteria were used to measure low back pain, leg pain, and disability. For radiologic evaluation, disc height, lumbar lordosis, segmental angle, and bone union were examined. Postoperative complications were also analyzed. At the last follow-up, good or excellent results were obtained in 50 cases of PLF (80.7%), 50 cases of PLIF (87.8%), and 41 cases of PLF+PLIF (85.5%). No statistical differences were found among the 3 groups (P = 0.704). All methods indicated significant improvement in the disc height (P < 0.05), with PLF having the highest loss in disc height. Lumbar lordosis and segmental angle increased significantly, and improvement of the segmental angle in the 3 fusion methods had statistically significant differences. The nonunion rates at the last follow-up in the 3 fusion groups were not statistically significant, with 8% in group 1, 5% in group 2, and 4% in group 3 (P > 0.05). Complications included deep infection in 3 cases, transient nerve palsy in 4, permanent nerve palsy in 1, and donor site pain in 6. No significant differences in clinical results and union rates were found among the 3 fusion methods. PLIF had better sagittal balance than PLF. PLIF without PLF had advantages of the elimination of donor site pain, shorter operating time, and less blood loss.