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Study Design: A retrospective case series.Objective: The aim of this study was to introduce the prevention of total hip arthroplasty (THA) dislocation using an implant impingement simulation after spinal corrective fusion and to verify the outcomes.Summary Of Background Data: A high dislocation rate was found among patients who underwent spinal deformity corrective fusion with previous THA. To avoid dislocation, an appropriate position of the stem and cup is important, but the pelvic inclination may change after corrective fusion for spinal deformity.Methods: Twelve consecutive patients (two men, 10 women; average age, 72.1 [range, 55-81] years during spine surgery) with previous THA were included. Data were retrospectively retrieved from a single-center's prospectively collected database of adult spinal deformity operation. Before surgery, anterior implant impingement simulation in THA was performed using computed tomography-based software. The tolerable pelvic tilt (PT) in which the anterior implant impingement occurred in the hip at the 120° flexion position was measured. The lumbar lordosis angle was deliberately reduced during spinal surgery according to the tolerable PT. The effect of the implant impingement simulation was verified by comparison with patients who underwent surgery before simulation (before 2014).Results: THA dislocation occurred in six patients: four of five (80%) in the non-simulation, and two of seven (28.6%) in the simulation group. The difference between the preoperative and tolerable PT angles was-25° to 33°, and three patients had negative angles. In these three patients, the risk of anterior impingement and THA dislocation significantly increased with correction of lumbar lordosis if the PT was anterior. Two patients experienced repeated THA dislocation with postoperative and tolerable PT angle differences of 2° and -23°.Conclusion: Our simulation of anterior implant impingement and subsequent adjustment of the degree of spinal correction was useful to prevent dislocation. However, this method did not prevent dislocation in some patients.Level of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study of postoperative outcomes of adult spinal deformity (ASD) surgery.Objective: To clarify the differences in postoperative outcomes depending on the presence or absence of thoracic compensatory changes among patients with a T1 slope (TS) more than 40°.Summary Of Background Data: Loss correction after ASD surgery is more likely to occur when preoperative TS is more than 40°. When preoperative TS is more than 40°, some cases involve compensatory changes in the thoracic spine and decreased thoracic kyphosis (TK); others involve increased TK without compensatory changes.Methods: Seventy-nine patients with TS more than 40° who underwent ASD surgery were enrolled and separated into compensated and noncompensated groups (group C: TK <40°; group NC: TK ≥40°). Radiographic parameters obtained by whole-spine standing x-ray, the Oswestry Disability Index (ODI), and Scoliosis Research Society-22 (SRS-22) questionnaire were assessed.Results: There were 41 patients in group C and 38 patients in group NC. Preoperative significant differences in TS did not disappear after surgery (preoperative TS: group C and group NC = 46° and 55°, P < 0.001; just after surgery: group C and group NC = 27° and 40°, P < 0.001; 2 years later: group C and group NC = 34° and 47°, P < 0.001). There were no significant differences in ODI and all domains of the SRS-22 before surgery. However, 2 years after the surgery, ODI (38%), pain (3.5), self-image (3.0), and total (3.2) values of the SRS-22 for group NC were significantly worse than those (28%, 4.0, 3.4, and 3.5, respectively) for group C (P < 0.05).Conclusion: Changes in the thoracic spine (TS and TK >40°) result in poor postoperative outcomes. Extending the upper instrumented vertebra (UIV) to the upper thoracic spine must be considered. Even when TS is more than 40°, TK less than 40°, and upper instrumented vertebra set to the lower thoracic level result in good postoperative outcomes.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective study of postoperative delirium after adult spinal deformity (ASD) surgery.Objective: To identify the risk factors of post-ASD surgery delirium, including nutritional state before surgery.Summary Of Background Data: Recently, malnutrition was reported as one of the risk factors of delirium. The prognostic nutritional index (PNI) and controlling nutritional status index (CONUT) scores are simple methods of nutritional evaluation. However, there are no reports that verify that delirium is related to the PNI and CONUT score in patients who have undergone ASD surgery.Methods: A consecutive 319 patients who underwent ASD surgery were divided into a delirium group (group D) or nondelirium group (group ND). Preoperative risk factors, including PNI, were assessed.Results: Group D consisted of 30 patients and group ND consisted of 289 patients. There was significant difference in age (group D:group ND = 73:62, P = 0.000), serum albumin (4.2:4.3, P = 0.028), operative time (422:395 min, P = 0.029), PNI score (49:52, P = 0.011), and CONUT score (1.7:1.1, P = 0.046). Using multiple logistic regression analysis, we found significant risk factors for delirium to be age (P = 0.006, odds ratio = 1.11, 95% confidence interval = 1.03-1.19) and PNI (P = 0.003, odds ratio = 0.87, 95% confidence interval = 0.79-0.96). A receiver operating characteristic curve showed that the cut-off value of PNI and age for delirium were 49.7 and 68.5 years, respectively.Conclusion: The risk factors of postoperative delirium after ASD surgery were PNI less than 49.7 and age more than 68.5 years. Patients who undergo ASD surgery beyond these preoperative cut-off values should be cautioned about delirium and be required to provide adequate informed consent.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A prospective case series analysis.Objective: The purpose of this study was to investigate the degree of difficulty in daily activities of adult spinal deformity (ASD) patients after corrective long fusion to the pelvis, with an emphasis on bend forward activities.Summary Of Background Data: No prospective studies have been reported regarding the postoperative impairments and their time course after long fusion in ASD patients.Methods: One-hundred three patients [26 men, 77 women; mean age 68 (50-82) years] who underwent corrective long fusion from the thoracic spine to the pelvis were included. As a control group, 578 volunteers [213 men, 365 women; mean age 72 (50-84)] who underwent musculoskeletal examination were included. Seven daily activities were assessed using Disability Scores (DS10), which ask patients to rate the difficulty of actions from 1 (very easy) to 10 (very difficult). The activities selected were a) gait, b) ability to trim toe nails, c) lie supine, d) perform personal hygiene, e) put on pants, f) pick up an item from the floor, and g) get down on all fours. Each of these activities were rated by all volunteers and patients at five assessment points in 2 years. Questionnaires (ODI, SRS-22, and DS10) were administered preoperatively, at discharge, 6 months, 1 year, and 2 years postoperatively. Radiographic parameters and clinical results of the control group were compared with those of the ASD patients and the patients with different upper instrumented vertebrae.Results: Although successful clinical results and deformity corrections were achieved, the ASD patients reported significant difficulty in b), d), e), f), and g) after the surgery (all P < 0.0001), regardless of the fusion length. The difficulty gradually improved toward 2 years but did not reach preoperative status.Conclusion: Activities requiring patients to bend forward were more difficult for elderly ASD patients postoperatively.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: Retrospective study.Objective: To determine the prevalence of loss in fixed segment alignment after surgical correction of adult spinal deformity (ASD) and identify associated risk factors.Summary Of Background Data: Altered fixed segment alignment influences global spinal alignment; however, associated risk factors have not been determined.Methods: Data of 63 patients with ASD (55 females; mean age, 68.0 yrs), who underwent corrective fusion from the lower thoracic spine to the pelvis and completed the 2-year follow up, were retrospectively analyzed. Change in alignment early postoperatively and at 2 years postoperatively was evaluated using the fixed segmental angle (FSA) and fixed vertebral angle (FVA). The predictive value of the following parameters was evaluated: age, sex, body mass index (BMI), high grade osteotomy, rod material, screw loosening, spinopelvic parameters [T1 pelvic angle (TPA), sagittal vertical axis (SVA), pelvic tilt (PT), lumbar lordosis (LL), thoracic kyphosis (TK), and proximal junctional kyphosis (PJA), and Oswestry Disability Index (ODI) scores].Results: Change of 2.4° in FSA and -3.1° in FVA were identified 2 years postoperatively, with higher intrarater and interrater reliability for FSA. Based on minimal detectable change in FSA, patients were classified into two groups: (+) loss (ΔFSA >3°) and (-) loss (ΔFSA ≤3°). Correction loss occurred in 17 patients; these patients had a greater BMI, higher rate of high-grade osteotomies, commercially pure titanium (CP) rods implanted, screw loosening, higher preoperative and postoperative TPA, and higher TPA, SVA, and PT after 2 years, than patients without correction loss.Conclusion: The loss of sagittal fixed segment alignment was relatively high at 27%. Greater BMI, high-grade osteotomies, CP rod use, and sagittal malalignment were associated with correction loss after ASD surgery.Level Of Evidence: 4. [ABSTRACT FROM AUTHOR]

Study Design: Longitudinal cohort.Objective: The present study aimed to document changes in posture and lower extremity kinematics during gait in patients with adult spinal deformity (ASD) after extensive corrective surgery.Summary Of Background Data: Standing radiographic parameters are typically used to evaluate patients with ASD. Previously, preoperative walking and standing posture discrepancy were reported in patients with ASD. We did not include comparison between before and after surgery. Therefore, we thought that pre- and postoperative evaluations for patients with ASD should include gait analysis.Methods: Thirty-nine patients with ASD (5 men, 34 women; mean age, 71.0 ± 6.1) who underwent posterior corrective fixation surgeries from the thoracic spine to the pelvis were included. A 4-m walk was recorded and analyzed. Sagittal balance while walking was calculated as the angle between the plumb line on the side and the line connecting the greater trochanter and pinna while walking (i.e., the gait-trunk tilt angle [GTA]). We measured maximum knee extension angle during one gait cycle, step length (cm), and walking speed (m/min). Radiographic parameters were also measured.Results: The mean GTA and the mean maximum knee extension angle significantly improved from 13.4° to 6.4°, and -13.3° to -9.4°(P < 0.001 and P = 0.006), respectively. The mean step length improved from 40.4 to 43.1 cm (P = 0.049), but there was no significant change in walking speed (38.4 to 41.5 m/min, P = 0.105). Postoperative GTA, maximum knee extension angle and step length correlated with postoperative pelvic incidence minus lumbar lordosis (r = 0.324, P = 0.044; r = -0.317, P = 0.049; r = -0.416, P = 0.008, respectively).Conclusion: Our results suggest that postoperative posture, maximum knee extension angle, and step length during gait in patients with ASD improved corresponding to how much correction of the sagittal spinal deformity was achieved.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]