Adolescent Idiopathic Scoliosis Treated by Posterior Spinal Segmental Instrumented Fusion : When Is Fusion to L3 Stable?

Objective@#: The purpose of this study was to identify risk factors for distal adding on (AO) or distal junctional kyphosis (DJK) in adolescent idiopathic scoliosis (AIS) treated by posterior spinal fusion (PSF) to L3 with a minimum 2-year follow-up. @*Methods@#: AIS patients undergoing PSF to L3 by two senior surgeons from 2000–2010 were analyzed. Distal AO and DJK were deemed poor radiographic results and defined as >3 cm of deviation from L3 to the center sacral vertical line (CSVL), or >10° angle at L3–4 on the posterior anterior- or lateral X-ray at ultimate follow-up. New stable vertebra (SV) and neutral vertebra (NV) scores were defined for this study. The total stability (TS) score was the sum of the SV and NV scores. @*Results@#: Ten of 76 patients (13.1%) were included in the poor radiographic outcome group. The other 66 patients were included in the good radiographic outcome group. Lower Risser grade, more SV-3 (CSVL doesn’t touch the lowest instrumented vertebra [LIV]) on standing and side bending films, lesser NV and TS score, rigid L3–4 disc, more rotation and deviation of L3 were identified risk factors for AO or DJK. Age, number of fused vertebrae, curve correction, preoperative coronal/sagittal L3–4 disc angle did not differ significantly between the two groups. Multiple logistic regression results indicated that preoperative Risser grade 0, 1 (odds ratio [OR], 1.8), SV-3 at L3 in standing and side benders (OR, 2.1 and 2.8, respectively), TS score -5, -6 at L3 (OR, 4.4), rigid disc at L3–4 (OR, 3.1), LIV rotation >15° (OR, 2.9), and LIV deviation >2 cm from CSVL (OR, 2.2) were independent predictive factors. Although there was significant improvement of the of Scoliosis Research Society-22 average scores only in the good radiographic outcome group, there was no significant difference in the scores between the groups. @*Conclusion@#: The prevalence of AO or DJK at ultimate follow-up for AIS with LIV at L3 was 13.1%. To prevent AO or DJK following fusion to L3, we recommend that the CSVL touch L3 in both standing and side bending, TS score is -4 or less, the L3/4 disc is flexible, L3 is neutral (<15°) and ≤2 cm from the midline and the patient is ≥ Risser 2.

Adolescent Idiopathic Scoliosis Treated by Posterior Spinal Segmental Instrumented Fusion : When Is Fusion to L3 Stable?

Objective@#: The purpose of this study was to identify risk factors for distal adding on (AO) or distal junctional kyphosis (DJK) in adolescent idiopathic scoliosis (AIS) treated by posterior spinal fusion (PSF) to L3 with a minimum 2-year follow-up. @*Methods@#: AIS patients undergoing PSF to L3 by two senior surgeons from 2000–2010 were analyzed. Distal AO and DJK were deemed poor radiographic results and defined as >3 cm of deviation from L3 to the center sacral vertical line (CSVL), or >10° angle at L3–4 on the posterior anterior- or lateral X-ray at ultimate follow-up. New stable vertebra (SV) and neutral vertebra (NV) scores were defined for this study. The total stability (TS) score was the sum of the SV and NV scores. @*Results@#: Ten of 76 patients (13.1%) were included in the poor radiographic outcome group. The other 66 patients were included in the good radiographic outcome group. Lower Risser grade, more SV-3 (CSVL doesn’t touch the lowest instrumented vertebra [LIV]) on standing and side bending films, lesser NV and TS score, rigid L3–4 disc, more rotation and deviation of L3 were identified risk factors for AO or DJK. Age, number of fused vertebrae, curve correction, preoperative coronal/sagittal L3–4 disc angle did not differ significantly between the two groups. Multiple logistic regression results indicated that preoperative Risser grade 0, 1 (odds ratio [OR], 1.8), SV-3 at L3 in standing and side benders (OR, 2.1 and 2.8, respectively), TS score -5, -6 at L3 (OR, 4.4), rigid disc at L3–4 (OR, 3.1), LIV rotation >15° (OR, 2.9), and LIV deviation >2 cm from CSVL (OR, 2.2) were independent predictive factors. Although there was significant improvement of the of Scoliosis Research Society-22 average scores only in the good radiographic outcome group, there was no significant difference in the scores between the groups. @*Conclusion@#: The prevalence of AO or DJK at ultimate follow-up for AIS with LIV at L3 was 13.1%. To prevent AO or DJK following fusion to L3, we recommend that the CSVL touch L3 in both standing and side bending, TS score is -4 or less, the L3/4 disc is flexible, L3 is neutral (<15°) and ≤2 cm from the midline and the patient is ≥ Risser 2.

Outcomes of Non-Operative Management for Pseudarthrosis after Pedicle Subtraction Osteotomies at Minimum 5 Years Follow-Up

OBJECTIVE: Minimal data exist regarding non-operative management of suspected pseudarthrosis after pedicle subtraction osteotomy (PSO). This study reports radiographic and clinical outcomes of non-operative management for post-PSO pseudarthrosis at a minimum 5 years post-detection. METHODS: Nineteen consecutive patients with implant breakage indicating probable pseudarthrosis after PSO surgery (13 women/six men; mean age at surgery, 58 years) without severe pain and disability were treated with non-operative management (mean follow-up, 5.8 years; range, 5–10 years). Non-operative management included medication, intermittent brace wearing and avoidance of excessive back strain. Radiographic and clinical outcomes analysis was performed. RESULTS: Sagittal vertical axis (SVA), proximal junctional angle, thoracic kyphosis achieved by a PSO were maintained after detection of pseudarthrosis through ultimate follow-up. Lumbar lordosis and PSO angle decreased at final follow-up. There was no significant change in Oswestry Disability Index (ODI) scores and Scoliosis Research Society (SRS) total score, or subscales of pain, self-image, function, satisfaction and mental health between detection of pseudarthrosis and ultimate follow-up. SVA greater than 11 cm showed poorer ODI and SRS total score, as well as the pain, self-image, and function subscales (p<0.05). CONCLUSION: Non-operative management of implant failure of probable pseudarthrosis after PSO offers acceptable outcomes even at 5 years after detection of implant breakage, provided SVA is maintained. As SVA increased, outcome scores decreased in this patient population.

Outcomes of Non-Operative Management for Pseudarthrosis after Pedicle Subtraction Osteotomies at Minimum 5 Years Follow-Up

OBJECTIVE: Minimal data exist regarding non-operative management of suspected pseudarthrosis after pedicle subtraction osteotomy (PSO). This study reports radiographic and clinical outcomes of non-operative management for post-PSO pseudarthrosis at a minimum 5 years post-detection.METHODS: Nineteen consecutive patients with implant breakage indicating probable pseudarthrosis after PSO surgery (13 women/six men; mean age at surgery, 58 years) without severe pain and disability were treated with non-operative management (mean follow-up, 5.8 years; range, 5–10 years). Non-operative management included medication, intermittent brace wearing and avoidance of excessive back strain. Radiographic and clinical outcomes analysis was performed.RESULTS: Sagittal vertical axis (SVA), proximal junctional angle, thoracic kyphosis achieved by a PSO were maintained after detection of pseudarthrosis through ultimate follow-up. Lumbar lordosis and PSO angle decreased at final follow-up. There was no significant change in Oswestry Disability Index (ODI) scores and Scoliosis Research Society (SRS) total score, or subscales of pain, self-image, function, satisfaction and mental health between detection of pseudarthrosis and ultimate follow-up. SVA greater than 11 cm showed poorer ODI and SRS total score, as well as the pain, self-image, and function subscales (p<0.05).CONCLUSION: Non-operative management of implant failure of probable pseudarthrosis after PSO offers acceptable outcomes even at 5 years after detection of implant breakage, provided SVA is maintained. As SVA increased, outcome scores decreased in this patient population.

Selection of the Optimal Distal Fusion Level in Posterior Instrumentation and Fusion for Thoracic Hyperkyphosis: The Sagittal Stable Vertebra Concept / 대한척추외과학회지

STUDY DESIGN: A retrospective study for clinical, radiographic assessment. OBJECTIVES: To determine the appropriate level of distal fusion for the posterior instrumentation and fusion for thoracic hyperkyphosis by investigating the relationship between the sagittal stable (the most proximal vertebra touched by the vertical line from the posterior-superior corner of the sacrum), first lordotic (just caudal to the first lordotic disc) and lowest instrumented vertebrae. LITERATURE REVIEW SUMMARY: It has been recommended that the distal level of fusion for thoracic hyperkyphosis should include not only the distal end vertebra of kyphosis, but also the first lordotic disc beyond the transitional zone, distally. However, distal junctional breakdown was noted, even when these rules have been followed. MATERIALS AND METHODS: Thirty-one patients, with a mean age of 18, ranging from 13 to 38 years, who underwent long posterior instrumentation and fusion for thoracic hyperkyphosis, with a minimum of 2 years of follow up, were reviewed. The preoperative diagnosis included: Scheuermann`s disease (n=29), posttraumatic kyphosis (n=1) and postlaminectomy kyphosis (n=1). According to the level of distal fusion, the patients were divided into two groups. Group I (n=24): lowest instrumented vertebra (LIV), including the sagittal stable vertebra (SSV), Group II (n=7): lowest instrumented vertebra proximal to the sagittal stable vertebra. Patients were evaluated utilizing both standing radiographs and chart reviews. RESULTS: The mean thoracic kyphosis was 86.6+/-8.5 before surgery, which had been corrected to 53.0+/-10.4 by the final follow-up, with a correction rate of 39%. The average sagittal balance was slightly negative (0.24+/-3.8 cm) before surgery, and became more negative (1.33+/-2.8 cm) by the final follow-up. There were no statistical differences in the thoracic kyphosis between the two 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, preoperatively, than at the final follow-up in Group I (p=0.003). In Group I, distal junctional problems developed in only 2 of the 24 (8%) patients, whereas in Group II, they occurred in 5 of the 7 (71%) patients (p<0.05). Despite extending the fusion to the first lordotic vertebra, distal junctional problems developed in 3 of the 8 (38%) patients. CONCLUSIONS: The distal end of the fusion for thoracic hyperkyphosis should include the sagittal stable vertebra. The levels of distal fusion that include the first lordotic vertebra, but not the sagittal stable vertebra, are not always appropriate for the prevention of postoperative distal junctional kyphosis.

Selection of the Optimal Distal Fusion Level in Posterior Instrumentation and Fusion for Thoracic Hyperkyphosis: The Sagittal Stable Vertebra Concept / 대한척추외과학회지

STUDY DESIGN: A retrospective study for clinical, radiographic assessment. OBJECTIVES: To determine the appropriate level of distal fusion for the posterior instrumentation and fusion for thoracic hyperkyphosis by investigating the relationship between the sagittal stable (the most proximal vertebra touched by the vertical line from the posterior-superior corner of the sacrum), first lordotic (just caudal to the first lordotic disc) and lowest instrumented vertebrae. LITERATURE REVIEW SUMMARY: It has been recommended that the distal level of fusion for thoracic hyperkyphosis should include not only the distal end vertebra of kyphosis, but also the first lordotic disc beyond the transitional zone, distally. However, distal junctional breakdown was noted, even when these rules have been followed. MATERIALS AND METHODS: Thirty-one patients, with a mean age of 18, ranging from 13 to 38 years, who underwent long posterior instrumentation and fusion for thoracic hyperkyphosis, with a minimum of 2 years of follow up, were reviewed. The preoperative diagnosis included: Scheuermann`s disease (n=29), posttraumatic kyphosis (n=1) and postlaminectomy kyphosis (n=1). According to the level of distal fusion, the patients were divided into two groups. Group I (n=24): lowest instrumented vertebra (LIV), including the sagittal stable vertebra (SSV), Group II (n=7): lowest instrumented vertebra proximal to the sagittal stable vertebra. Patients were evaluated utilizing both standing radiographs and chart reviews. RESULTS: The mean thoracic kyphosis was 86.6+/-8.5 before surgery, which had been corrected to 53.0+/-10.4 by the final follow-up, with a correction rate of 39%. The average sagittal balance was slightly negative (0.24+/-3.8 cm) before surgery, and became more negative (1.33+/-2.8 cm) by the final follow-up. There were no statistical differences in the thoracic kyphosis between the two 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, preoperatively, than at the final follow-up in Group I (p=0.003). In Group I, distal junctional problems developed in only 2 of the 24 (8%) patients, whereas in Group II, they occurred in 5 of the 7 (71%) patients (p<0.05). Despite extending the fusion to the first lordotic vertebra, distal junctional problems developed in 3 of the 8 (38%) patients. CONCLUSIONS: The distal end of the fusion for thoracic hyperkyphosis should include the sagittal stable vertebra. The levels of distal fusion that include the first lordotic vertebra, but not the sagittal stable vertebra, are not always appropriate for the prevention of postoperative distal junctional kyphosis.