Shin Oe

The Influence of Age and Sex on Cervical Spinal Alignment Among Volunteers Aged Over 50

Study Design. Large cohort study of volunteers aged over 50. Objective. To investigate influence of age and sex on cervical sagittal alignment among volunteers aged over 50. Summary of Background Data. Few large-scale studies have described normative values in cervical spine alignment regarding age and sex among volunteers aged over 50. Methods. The study cohort included 656 volunteers aged 50 to 89 years. Pelvic tilt, sacral slope, pelvic incidence, lumbar lordosis, pelvic incidence−lumbar lordosis, thoracic kyphosis, T1 slope (T1S), cervical lordosis (CL), C7 sagittal vertical axis (C7 SVA), C2−C7 SVA, and T1S−CL were measured using whole spine and pelvic radiographs taken in the standing position. Health-related quality of life was assessed using the EuroQOL (EQ-5D) standardized instrument for measurement of health outcome and Oswestry Disability Index. Results. There were 36 subjects aged 50 to 59 years, 174 aged 60 to 69 years, 311 aged 70 to 79 years, and 135 aged 80 to 89 years. Average T1S for each decade was 32°, 31°, 33°, and 36° for males, and 28°, 29°, 32°, and 37° for females, respectively. Average C2–C7 SVA was 25, 28, 34, and 35 mm for males, and 20, 21, 22, and 28 mm for females, respectively. C2–C7 SVA 40 mm or more, T1S 40° or more, and T1S–CL 20° or more pertaining to EQ-5D were significantly worse in other cases. Conclusion. C2–C7 SVA was significantly greater in males among all age groups, particularly among those with C2–C7 SVA of 40 mm or more [males, 69% (82/118) vs. females, 33% (36/118)]. Sagittal parameters of cervical spine were significantly worse in males than females. C2–C7 SVA, T1S, and T1S–CL negatively influenced EQ-5D. These results help to explain the greater prevalence of cervical spondylotic myelopathy among elderly males. Level of Evidence: 3

Calculation of the Target Lumbar Lordosis Angle for Restoring an Optimal Pelvic Tilt in Elderly Patients With Adult Spinal Deformity.

Study Design. This investigation consisted of a cross-sectional study and a retrospective multicenter case series. Objective. This investigation sought to identify the ideal lumbar lordosis (LL) angle for restoring an optimal pelvic tilt (PT) in patients with adult spinal deformity (ASD). Summary of Background Data. To achieve successful corrective fusion in ASD patients with sagittal imbalance, it is essential to correct the sagittal spinal alignment and obtain a suitable pelvic inclination. We determined the LL angle that would restore the optimal PT following ASD surgery. Methods. The cross-sectional study included 184 elderly volunteers (mean age 64 years) with an Oswestry Disability Index score less than 20%. The relationship between PT or LL and the pelvic incidence (PI) in normal individuals was investigated. The second study included 116 ASD patients (mean age 66 years) who underwent thoracolumbar corrective fusion at 1 of 4 spine centers. The postoperative PT values were calculated using the parameters measured. On the basis of these studies, an ideal LL angle was determined. Results. In the cross-sectional study, the linear regression equation for the optimal PT as a function of PI was “optimal PT = 0.47 × PI – 7.5.” In the second study, the postoperative PT was determined as a function of PI and corrected LL, using the equation “postoperative PT = 0.7 × PI – 0.5 × corrected LL + 8.1.” The target LL angle was determined by mathematically equalizing the PTs of these 2 equations: “target LL = 0.45 × PI + 31.8.” Conclusion. The ideal LL angle can be determined using the equation “LL = 0.45 × PI + 31.8,” which can be used as a reference during surgical planning in ASD cases. Level of Evidence: 4

Preoperative T1 Slope More Than 40° as a Risk Factor of Correction Loss in Patients With Adult Spinal Deformity.

Study Design. A retrospective study of surgical outcomes of adult spinal deformity (ASD) cases. Objective. The aim of the study was to investigate the effects of high T1 slope (T1S) on surgical outcomes in patients with ASD. Summary of Background Data. Few studies have evaluated the surgical outcomes of patients with ASD with cervical deformities. Methods. Eighty-eight patients with ASD who underwent posterior spinal corrective fusion were assigned to either group A (T1S <40°) or group B (T1S ≥40°). Whole-spine standing radiographs of both groups were preoperatively assessed: at first standing after the surgery and at 1 and 2 years postoperatively. Results. There were 56 patients in group A and 32 in group B. The preoperative C7 sagittal vertical axis (SVA) improved from 61 to 41 mm in group A and from 161 to 64 mm in group B at first standing after the surgery. C7 SVA at 2 years after the surgery was, however, 57 mm in group A and 98 mm in group B because of correction loss (P = 0.003). T1S measurements before and immediately after the surgery and 2 years after the surgery were, however, 25°, 23°, and 27° in group A and 53°, 36°, and 41° in group B, respectively. There were no significant differences among measurements in group A. Those in group B were, however, significantly improved in the first standing, but T1S of 40° or higher deteriorated toward 2 years after the surgery. Conclusion. Among patients with T1S of 40° or higher, C7 SVA improved immediately after the surgery but worsened at 2 years after the surgery. These results suggested that cervicothoracic parameters were important predictors of correction loss. Level of Evidence: 4

Discrepancy between Standing Posture and Sagittal Balance during Walking in Adult Spinal Deformity Patients.

Study Design. Retrospective case series. Objective. The present study aimed to determine the characteristics of patients with adult spinal deformity (ASD) with a discrepancy between standing and walking postures. Summary of Background Data. Standing radiographic parameters are typically used to evaluate patients with ASD. Patients with ASD with relatively good sagittal alignment on standing radiography have, however, been reported to walk with a forward trunk tilt. Methods. Patients with ASD (n = 93; 13 men, 80 women; mean age, 65.0 yr) who underwent corrective surgery and preoperative gait analysis at our hospital between 2011 and 2013 were included. Spine radiographs and gait analysis data were acquired preoperatively. Standing-trunk tilt angle (STA) on lateral standing x-ray, gait-trunk tilt angle (GTA) from lateral gait images, and radiographic parameters of the spine and pelvis (lumbar lordosis [LL], pelvic tilt, and sagittal vertical axis) were measured. We calculated the increasing trunk tilt angle (ITA), by subtracting the STA from the GTA, for use as an index of discrepancy between standing posture and sagittal balance during walking. We examined the relation between radiographic parameters and ITA. Results. The mean preoperative STA and GTA were 3.5° and 11.1°, respectively. The mean preoperative ITA, which represents the degree of discrepancy between standing posture and sagittal balance during walking, was 7.6°. The mean preoperative sagittal vertical axis, LL, pelvic incidence (PI), pelvic tilt, and PI minus LL were 102.6 mm, 20.3°, 52.9°, 32.1°, and 32.6°, respectively. The PI minus LL mismatch was positively correlated with the ITA (R = 0.237, P = 0.023). In particular, patients with ASD with a PI minus LL mismatch of more than 40° had a significantly greater ITA. Conclusion. Gait analysis revealed that a preoperative standing-walking discrepancy is associated with severe PI − LL mismatch. Level of Evidence: 4

Relationship between Spinal Hemangioblastoma Location and Age

Study Design Retrospective case series. Purpose To investigate the relationship between tumor location and clinical characteristics. Overview of Literature Hemangioblastoma is a rare disease that develops in the central nervous system. Magnetic resonance imaging (MRI) is useful to evaluate hemangioblastomas. Hemangioblastomas location is designated as intramedullary, intramedullary+extramedullary, or extramedullary by MRI. Methods We analyzed 11 patients who underwent surgery for spinal hemangioblastoma. Using T1 contrast axial MRI data, the cases were divided into three groups (intramedullary, intramedullary+extramedullary, and extramedullary). Patient demographics, MRI findings, and preoperative neurological status were analyzed and compared for each group. Results The average age of patients with intramedullary, intramedullary+extramedullary, and extramedullary hemangioblastoma was 34.0, 64.4, and 67.5 years, respectively. Patients in the intramedullary hemangioblastoma group were younger than the other groups. Extramedullary cases had a smaller syrinx compared to the other groups. Conclusions Age may play an important role in the hemangioblastoma tumor location and the subsequent diagnosis by an MRI.

Treatment strategy for rod fractures following corrective fusion surgery in adult spinal deformity depends on symptoms and local alignment change

OBJECTIVE Despite the significant incidence of rod fractures (RFs) following long-segment corrective fusion surgery, little is known about the optimal treatment strategy. The objectives of this study were to investigate the time course of clinical symptoms and treatments in patients with RFs following adult spinal deformity (ASD) surgery and to establish treatment recommendations. METHODS This study was a retrospective case series of patients with RFs whose data were retrieved from a prospectively collected single-center database. The authors reviewed the cases of 304 patients (mean age 62.9 years) who underwent ASD surgery. Primary symptoms, time course of symptoms, and treatments were investigated by reviewing medical records. Standing whole-spine radiographs obtained before and after RF development and at last follow-up were evaluated. Osseous union was assessed using CT scans and intraoperative findings. RESULTS There were 54 RFs in 53 patients (mean age 68.5 years [range 41-84 years]) occurring at a mean of 21 months (range 6-47 months) after surgery. In 1 patient RF occurred twice, with each case at a different time and level, and the symptoms and treatments for these 2 RFs were analyzed separately (1 case of revision surgery and 1 case of nonoperative treatment). The overall rate of RF observed on radiographs after a minimum follow-up of 1 year was 18.0% (54 of 300 cases). The clinical symptoms at the time of RF were pain in 77.8% (42 of 54 cases) and no onset of new symptoms in 20.5% (11 of 54 cases). The pain was temporary and had subsided in 19 of 42 cases (45%) within 2 weeks. In 36 of the 54 cases (66.7%) (including the first RF in the patient with 2 RFs), patients underwent revision surgery at a mean of 116 days (range 5-888 days) after diagnosis. In 18 cases patients received only nonoperative treatment as of the last follow-up, including 17 cases in which the patients experienced no pain and no remarkable progression of deformity (mean 18.5 months after RF development). CONCLUSIONS This analysis of 54 RFs in 53 patients following corrective fusion surgery for ASD demonstrates a relationship between symptoms and alignment change. Revision surgeries were performed in a total of 36 cases. Nonoperative care was offered in 18 (33.3%) of 54 cases at the last follow-up, with no additional symptoms in 17 of the 18 cases. These data offer useful information regarding informed decision making for patients in whom an RF occurs after ASD surgery.

Proximal junctional kyphosis in adult spinal deformity with long spinal fusion from T9/T10 to the ilium

BACKGROUND Proximal junctional kyphosis (PJK) is a common complication after corrective long spinal fusion for adult spinal deformity. Although some reports evaluated PJK after corrective long spinal fusion, there is no report about analysis of PJK cases in the same fusion area. The purpose of this study to investigated the incidence of and risk factors for PJK in adults undergoing long spinal fusion from the distal thoracic vertebrae (T9/T10) to the ilium. METHODS We enrolled 56 adult patients (>40 years of age) who underwent posterior corrective surgery with same fusion area from T9 or T10 to the ilium for spinal deformity. Pre- and postoperative radiographic measurements included the sagittal vertical axis (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), and pelvic incidence minus LL (PI-LL). The Oswestry disability index (ODI) was used to evaluate patient outcomes preoperatively and one year after surgery. We analyzed the incidence for PJK and compared PJK and non-PJK cases. RESULTS PJK at the final follow-up occurred in 19 of 56 (33.9%) patients. The mean age and ODI were not significantly different between the PJK and non-PJK groups. Both two groups had good spinopelvic sagittal alignment after surgery in terms of SVA and PI-LL. Only three cases required revision surgery for symptomatic PJK. Three cases had history of rheumatoid arthritis and/or total hip arthroplasty surgery. CONCLUSIONS The incidence of PJK was 33.9%, and ODI was not significantly different between the PJK and non-PJK groups. Symptomatic PJK was only three cases and all of them had lower extremity joint disorders. We should pay attention also lower extremity joint to prevent symptomatic PJK at the lower thoracic level.

T1 Pelvic Angle Is a Useful Parameter for Postoperative Evaluation in Adult Spinal Deformity Patients.

Study Design. Retrospective review. Objective. We investigated validity of T1 pelvic angle (TPA) for postoperative assessment and determined its target value for corrective scoliosis surgery. Summary of Background Data. TPA is a novel spinopelvic parameter accounting for both pelvic retroversion and trunk anteversion. As an angle, it is less affected by posture and correlates well with health-related quality of life in adult spinal deformity patients. According to our study in elderly volunteers, the threshold TPA value for disability (Oswestry Disability Index [ODI] score >20) was approximately 20°. Methods. Seventy adult scoliosis patients (5 men and 65 women; mean age, 67.8 yr) who underwent spinal deformity surgeries and were followed up for at least 2 years postoperatively were studied. The following parameters based on whole-spine and pelvic radiography were assessed preoperatively, soon after operation, and 2 years postoperatively: C7-central sacral vertical line, TPA, sagittal vertical axis (SVA), pelvic tilt, and pelvic incidence minus lumbar lordosis. ODI and Scoliosis Research Society-22 scores were obtained preoperatively and 2 years postoperatively. Based on postoperative TPA, patients were divided into two groups: ⩽20° (group G) and greater than 20° (group P). Results. TPA and SVA correlated with health-related quality of life. Two years postoperatively, TPA best correlated with ODI and Scoliosis Research Society-22 scores, although all parameters correlated with them, and TPA soon after operation best correlated with ODI scores 2 years postoperatively. Two years postoperatively, each parameter and ODI scores in group G were better than those in group P. Conclusion. The correlation results showed that TPA appropriately assessed clinical outcomes following spinal deformity surgery. TPA assessed soon after operation correlated with ODI score 2 years postoperatively, and thus predicted prognosis. Because patients whose postoperative corrected TPA was 20° or lesser had better spinopelvic parameters and ODI scores 2 years postoperatively, TPA 20° or lesser was the proper target value for corrective surgery. Level of Evidence: 4

Postoperative Change of Thoracic Kyphosis after Corrective Surgery for Adult Spinal Deformity

Introduction Correction of lumbar lordosis is the primary goal of surgical treatment of adult spinal deformity. However, only limited research has evaluated the effects of this correction on the adaptive curvature of the thoracic spine. The purpose of this study is to evaluate the change in thoracic curvature after corrective surgery to restore lumbar lordosis in patients with adult spinal deformity. Methods We completed a retrospective analysis of the radiological data of 65 patients, ≥50 years old, who underwent corrective surgery of lumbar spine lordosis from any level below T8 to the ilium. Patients with insufficient correction, defined by a pelvic incidence minus lumbar lordosis angle (PI-LL) > 10°, were excluded, with the data of 43 patients included in the analysis. The following radiological measures of spinal alignment were measured at three time points, preoperatively, on the first day of standing postoperatively and at 2 years post-surgery: sagittal vertical axis (SVA), lumbar lordosis (LL), thoracic kyphosis (TK), pelvic tilt (PT), and PI-LL. Results Postoperative change in TK was correlated to preoperative TK and age. The increase in TK was larger for patients <75 years of age, increasing from 23.1° to 38.0° after surgery and to 46.7° at 2-years postoperatively. In contrast, for patients >75 years, TK remained largely unchanged at 37.8° just after surgery but increased substantively to 50.1° at the 2-year follow-up. The postoperative change in TK immediately after surgery was determined using equation “predict change in TK = −0.21 × age − 0.6 × preoperative TK + 41.8” by multiple regression analysis. Conclusions Reciprocal change in TK after lumbar spine correction is correlated to preoperative TK and age.

Effect of position on lumbar lordosis in patients with adult spinal deformity

OBJECTIVEThe purpose of this study was to evaluate the effect of position on lumbar lordosis (LL) in adult spinal deformity (ASD) patients.METHODSThe authors evaluated the radiographic data of ASD patients who underwent posterior corrective fusion surgery from the thoracic spine to L5, S1, or the ilium for the treatment of ASD of the lumbar spine. The spinopelvic parameters were measured in the standing position preoperatively. LL was also evaluated in the supine position preoperatively and in the prone position on the surgical frame. Changes in LL were compared between groups.RESULTSEighty-five patients were included. The average LL in standing, supine, and prone positions was 11.8°, 24.3°, and 24.0°, respectively. LL increased significantly from standing to supine or prone position (p < 0.001). In 80 patients (94.1%), the difference between supine LL and prone LL was within 5°. Change in LL from standing to prone position was significantly higher in the severe deformity group.CONCLUSIONSThe lordotic effect of intraoperative prone positioning was remarkable in patients with severe deformities. LL in the supine position was approximately the same as that in the prone position. Therefore, assessing preoperative supine lateral lumbar radiographs enables one to plan corrective spinal surgeries in ASD patients.