Usefulness of anterior column release for segmental lordosis restoration in degenerative lumbar kyphosis.

OBJECTIVE: Three-column osteotomies (3COs) for surgical correction of lumbar kyphosis show a strong correction capacity, but this procedure carries high morbidity rates. The anterior column release (ACR) technique was developed as a less invasive procedure. In this study the authors aimed to evaluate sagittal alignment restoration using ACR and to determine factors that affect the degree of correction. METHODS: This study included 36 patients (68 cases) who underwent ACR of more than one level for adult spinal deformity. Parameters for regional sagittal alignment included segmental lordosis (SL). The parameters for global sagittal alignment included pelvic incidence, lumbar lordosis, sacral slope, pelvic tilt, and sagittal vertical axis (SVA). In addition, the interdiscal height (IDH) and difference of interdiscal angle (DIDA) were measured to evaluate the stiffness of the vertebra segment. The changes in SL were evaluated after ACR and the change of global sagittal alignment was also determined. Factors such as the location of the ACR level, IDH, DIDA, cage height, and additional posterior column osteotomy (PCO) were analyzed for correlation with the degree of SL correction. RESULTS: Thirty-six patients were included in this study. A total of 68 levels were operated with the ACR (8 levels at L2-3, 27 levels at L3-4, and 33 levels at L4-5). ACR was performed for 1 level in 10 patients, 2 levels in 20, and 3 levels in 6 patients (mean 1.9 ± 0.7 levels per patient). Mean follow-up duration was 27.1 ± 4.2 months. The mean SL of the total segment was 0.4° ± 7.2° preoperatively and increased by 15.3° ± 5.5° at the last follow-up (p < 0.001); thus, the mean increase of SL was 14.9° ± 8.1° per one ACR. Global sagittal alignment was also improved following SL restoration with SVA from 101.9 mm to 31.4 mm. The degree of SL correction was correlated with the location of ACR level (p = 0.041) and was not correlated with IDH, DIDA, cage height and additional PCO. CONCLUSIONS: This study demonstrated that the mean correction angle of SL was 14.9 per one ACR. The degree of disc space collapse and stiffness of segment did not affect the degree of correction by ACR.

The Long-term Fate of Asymptomatic Proximal Junctional Kyphosis Following Long Instrumented Fusion in Elderly Patients with Sagittal Imbalance.

STUDY DESIGN: Retrospective study. OBJECTIVE: The aim of this study was to investigate the long-term fate of asymptomatic PJK focusing on the elderly patients with sagittal imbalance by comparing the patients with and without PJK. SUMMARY OF BACKGROUND DATA: Most of previous studies demonstrated that PJK does not negatively affect the clinical outcome compared to that of the patients without PJK. The question "will the asymptomatic PJK remain asymptomatic even in long-term follow-up?" has not been answered yet because the previous results were based on the short follow-up duration. METHODS: Patients >60 years who underwent four or more level fusions to the sacrum for sagittal imbalance were followed up for >5 years. The radiographic and clinical outcomes were compared between PJK (n = 30) and non-PJK groups (n = 43). PJK was defined by proximal junctional angle (PJA) >10°. Only patients with >3 years of follow-up duration after PJK development were included in PJK group. The clinical outcome measures included visual analog scale (VAS) for the back and leg, Oswestry disability index (ODI), and Scoliosis Research Society (SRS)-22 scores. RESULTS: The mean age was 69.2 years. Total follow-up duration was 92.4 months. Time between PJK development and the last follow-up was 67.4 months in PJK group. Although there were no differences between the two groups in terms of pelvic incidence-lumbar lordosis mismatch, pelvic tilt, or sacral vertical axis, PJA significantly increased from 6.5° postoperatively to 21.2° at the final follow-up in the PJK group. The clinical outcomes were worse (such as VAS for the back, ODI, and SRS-22 scores) in the PJK group than in non-PJK group, except for the satisfaction domain. Three (10%) of 30 patients underwent a revision surgery for PJK progression. CONCLUSION: Even if PJK was asymptomatic at initial development, it progressed radiographically with time and eventually gave a negative impact on the clinical outcomes in long-term follow-up.Level of Evidence: 3.

Failure Types and Related Factors of Spinopelvic Fixation After Long Construct Fusion for Adult Spinal Deformity.

BACKGROUND: Rigid internal fixation of the spine is an essential part of adult spinal deformity (ASD) surgery. Despite the use of pelvic fixation and anterior column support, spinopelvic fixation failure (SPFF) still remains an issue. Few studies have evaluated the types of such failure or its related factors. OBJECTIVE: To classify the types of SPFF and investigate its risk factors, including the fusion status at L5-S1 on CT scan. METHODS: The study cohort consisted of ninety-eight ASD patients who underwent more than 4-level fusions to the sacrum with interbody fusion at L5-S1. Patients with SPFF were divided into the two groups: above-S1 and below-S1 failure groups. The patient, surgical, and radiographic variables in each group were compared to those of the no-failure group. The L5-S1 fusion status was assessed using 2-yr computed tomography (CT) scan. Univariate and multivariate analyses were performed to determine the risk factors for each failure group. RESULTS: The mean age was 68.5 yr. Follow-up duration was 55.7 mo. The SPFF developed in 46 (46.9%) patients at 32.7 mo postoperatively. There were 15 patients in the above-S1 failure group and 31 patients in the below-S1 failure group. Multivariate analysis revealed that nonunion at L5-S1 was a single risk factor for above-S1 failure. In contrast, the risk factors for below-S1 failure included a greater number of fused segments and postoperative less thoracic kyphosis. CONCLUSION: SPFF develops in different patterns with different risk factors. Above-S1 SPFF was associated with nonunion at L5-S1, while below-S1 SPFF was associated with mechanical stress.

Who Will Require Revision Surgery Among Neurologically Intact Patients with Proximal Junctional Failure After Surgical Correction of Adult Spinal Deformity?

STUDY DESIGN: Retrospective study. OBJECTIVE: To identify the risk factors for revision surgery among neurologically intact patients with proximal junctional failure (PJF) after adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: PJF following long fusion for ASD is a well-recognized complication that negatively affects clinical outcomes. However, revision surgery is not required for every patient with PJF especially if the patient does not present with neurologic deficit. Identifying the risk factors of revision surgery is necessary to determine who will need revision surgery as well as when is the right time for the revision surgery. METHODS: Sixty-nine neurologically intact patients with PJF following ASD surgery were followed up with more than 2 years after PJF development or until undergoing revision surgery. PJF was divided into ligamentous failure (proximal junctional angle [PJA] of more than 20°) and bony failure. According to the conduct of revision surgery, two groups (revision and no revision) were created. Risk factors for revision surgery were analyzed in univariate and multivariate analysis with regard to patient, surgical and radiographic variables. RESULTS: The mean age at the time of PJF development was 70.9 years. There were 45 patients with bony failure and 24 with ligamentous failure. Revision surgery was performed for 23 patients (33.3%). Multivariate analysis revealed that bony failure (odds ratio: 10.465) and PJA (odds ratio: 1.131) were significant risk factors. For those with bony failure, the cutoff value of PJA for performing revision surgery was calculated as 22°. The revision rate was significantly highest in patients (63.6%) with bony failure + PJA 22° or higher followed by patients (26.1%) with bony failure + PJA less than 22° and patients (12.5%) with ligamentous failure (P = 0.002). CONCLUSION: Bony failure with PJA of greater than 22° increased the likelihood for revision surgery. Therefore, early surgical intervention should be considered in these patients.Level of Evidence: 4.

Long-term benefits of appropriately corrected sagittal alignment in reconstructive surgery for adult spinal deformity: evaluation of clinical outcomes and mechanical failures.

OBJECTIVE: It has been well documented that optimal sagittal alignment is highly correlated with good clinical outcomes in adult spinal deformity (ASD) surgery. However, it remains to be determined whether the clinical benefit of appropriately corrected sagittal alignment can be maintained in the long term. Therefore, the aim of this study was to investigate whether appropriately corrected sagittal alignment continues to offer benefits over time with regard to clinical outcomes and mechanical failure. METHODS: Patients older than 50 years who underwent ≥ 4-level fusion for ASD and were followed up for ≥ 5 years were included in this study. Appropriateness of sagittal alignment correction was defined as pelvic incidence minus lumbar lordosis ≤ 10°, pelvic tilt ≤ 25°, and sagittal vertical axis ≤ 50 mm. Two groups were created based on this appropriateness: group A (appropriate) and group IA (inappropriate). Clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry Disability Index (ODI), and Scoliosis Research Society Outcomes Questionnaire-22 (SRS-22). The development of mechanical failures, such as rod fracture and proximal junctional kyphosis (PJK), was compared between the two groups. RESULTS: The study included 90 patients with a follow-up duration of 90.3 months. There were 30 patients in group A and 60 patients in group IA. The clinical outcomes at 2 years were significantly better in group A than in group IA in terms of the VAS scores, ODI scores, and all domains of SRS-22. At the final follow-up visit, back VAS and ODI scores were still lower in group A than they were in group IA, but the VAS score for leg pain did not differ between the groups. The SRS-22 score at the final follow-up showed that only the pain and self-image/appearance domains and the total sum were significantly higher in group A than in group IA. The incidence of rod fracture and PJK did not differ between the two groups. The rate of revision surgery for rod fracture or PJK was also similar between the two groups. CONCLUSIONS: The clinical benefits from appropriate correction of sagittal alignment continued for a mean of 90.3 months. However, the intergroup difference in clinical outcomes between groups A and IA decreased over time. The development of rod fracture or PJK was not affected by the appropriateness of sagittal alignment.

A Comparison of U-blade Gamma3 and Gamma3 Nails Used for the Treatment of Intertrochanteric Fractures.

PURPOSE: To compare outcomes (i.e., clinical and radiological findings, postoperative complication) in the fixation of intertrochanteric fractures with U-blade Gamma3 and Gamma3 nails. MATERIALS AND METHODS: A review of 162 patients (both male and female) treated for intertrochanteric fractures between December 2012 and December 2018 was conducted. All patients were older than 65 years of age and treated with U-blade Gamma3 (n=90) or Gamma3 (n=72) nails. Evaluations included: (i) screw-head position, (ii) fracture-reduction status, (iii) time to union, (iv) cases of cut-out, (v) tip-apex distance, and (vi) lag screw sliding distance. Differences in pre- and postoperative ambulatory ability was also investigated. RESULTS: There were no significant differences in baseline demographics between the two groups. While the lag-screw sliding distance was significantly shorter in U-blade Gamma3 nail group (4.7 mm vs. 3.6 mm; P=0.025), the mean time to union was similar between the groups (P=0.053). Three and six cases of cut-out were noted in the U-blade Gamma3 and Gamma3 nail groups, respectively (P=0.18), however no other postoperative complications were noted in either group. Lastly, there was no difference between the change from pre- to postoperative activity level between the groups (P=0.753). CONCLUSION: Of all the clinical and radiological outcomes assessed, the only significant improvement between those treated with U-Blade Gamma and Gamma3 nails was a shorter lag-screw sliding distance. These findings should benefit clinicians when deciding between the use of U-Blade Gamma or Gamma3 nails.