The use of lateral lumbar interbody fusion for identifying adult patients with spinal deformities treatable by short corrective fusion in 2-stage surgery.

BACKGROUND: To investigate and compare the surgical outcomes of short and thoracopelvic corrective fusion with our two-stage technique using lateral lumbar interbody fusion (LLIF) and posterior open surgery. METHODS: Consecutive patients with adult spinal deformities who underwent a planned two-stage anterior-posterior surgery, using LLIF for the first stage and posterior open corrective fusion for the second stage, with a minimum of 2 years of follow-up were included. Patients who underwent lumbar or lumbosacral corrective fusion and thoracopelvic corrective fusion were categorized into the short group and thoracopelvic groups, respectively. We investigated the spinopelvic parameters and patient-reported outcome measurements. RESULTS: Seventy-four consecutive patients (8 men, 66 women; average age, 70.0 years) were included. Ten patients underwent short corrective fusion following significant improvements in the symptoms and radiographic parameters post-LLIF. Several preoperative spinopelvic parameters were better in the short group. Compared to the thoracopelvic group, those who underwent short fusion had a poorer alignment 2 years postoperatively but with comparable results and a significantly higher function score on the Scoliosis Research Society-22 r (SRS-22r) questionnaire. The mean Oswestry Disability Index and SRS-22r scores significantly improved during the 2-year postoperative follow-up in both the groups. CONCLUSIONS: Short corrective fusion can be considered in patients whose symptoms and radiographic parameters significantly improve following LLIF. Patients who undergo short fusion with LLIF application have poorer alignment than those who undergo thoracopelvic fusion 2 years postoperatively; however, the results are comparable, and the function score is significantly improved.

Postoperative neurological complications in intradural extramedullary tumors: A 10-year experience of a single center.

BACKGROUND: Intradural extramedullary spinal cord tumors (IDEMs) cause neurological symptoms due to compression of the spinal cord and caudal nerves. The purpose of this study was to investigate the incidence of postoperative neurological complications after surgical resection of IDEM and to identify factors associated with such postoperative neurological complications. METHODS: We retrospectively analyzed 85 patients who underwent tumor resection for IDEM between 2010 and 2020. We investigated the postoperative worsening of neurological disorders. The patients were divided into two groups: those with and without postoperative neurological complications. Patient demographic characteristics, tumor level, histological type, and surgery-related factors were also compared. RESULTS: The mean age at the time of surgery was 57.4 years, and histological analysis revealed 45 cases of schwannoma, 34 cases of meningioma, three cases of myxopapillary ependymoma, one case of ependymoma, one case of hemangioblastoma and one case of lipoma. There were five cases (5.8%) of postoperative neurological complications, and four patients improved within 6 months after surgery, and one patient had residual worsening. There were no statistically significant differences in age, sex, tumor location, preoperative modified McCormick Scale grade, histology, tumor occupancy, or whether fixation was performed in the presence or absence of postoperative neurological complications. All four cases of meningioma with postoperative neurological complications had preoperative neuropathy and meningiomas were located in the anterior or lateral thoracic spine. CONCLUSIONS: Neurological complications after surgical resection for IDEM occurred in 5.8% of patients. Meningiomas with postoperative neurological complications located anteriorly or laterally in the thoracic spine.

Does Adult Spinal Deformity Affect Cardiac Function? A Prospective Perioperative Study.

STUDY DESIGN: Prospective comparative study. OBJECTIVE: The objective of this study was to investigate perioperative cardiac function using echocardiography in patients undergoing surgery for the adult spinal deformity (ASD). SUMMARY OF BACKGROUND DATA: Corrective surgery for ASD has increased, especially in older persons. However, perioperative complication rates remain high in ASD surgery, including cardiopulmonary complications. MATERIALS AND METHODS: This study included patients with ASD who underwent surgery between May 2016 and April 2018. A cardiologist performed all echocardiography imaging preoperatively and 2 weeks postoperatively. Left ventricular contractility was measured using left ventricular ejection fraction (LVEF), and right ventricular contractility was measured using tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular peak systolic velocity (S'). Spinopelvic radiographic parameters, the apices of thoracic kyphosis and lumbar lordosis, and the inflection point where the vertebral curvature changes from kyphosis to lordosis were also measured. Differences between preoperative and postoperative measurements for continuous variables were analyzed using a paired Student t test. Differences in continuous and categorical variables between two independent groups were analyzed using an unpaired Student t test and Fisher exact test, respectively. Multivariate logistic regression analyses were performed to detect influential factors. RESULTS: Sixty-one patients were included [12 males and 49 females; average age, 64.0 (22-84) yr]. LVEF, TAPSE, and S', respectively changed from 64.4%, 24.9 mm, and 14.3 cm/s to 65.4%, 25 mm, and 15 cm/s postoperatively with no significance. However, in LVEF<59.3% (average-1 SD), TAPSE<17 mm, and S'<11.8 cm/s cases, respectively, these increased significantly from 55.7%, 17.9 mm, and 10.5 cm/s to 60.9%, 21.4 mm, and 14.2 cm/s postoperatively ( P =0.036, 0.029, and 0.022, respectively). The LVEF<59.3% group showed a significantly lower inflection point level (1.5 vs. 2.9) preoperatively ( P =0.007). The S'<11.8 cm/s group showed significantly larger thoracic kyphosis (28.3° vs. 19.4°) preoperatively ( P =0.013). CONCLUSIONS: Perioperative cardiac function did not deteriorate after surgery in patients with ASD. In those with lower cardiac function preoperatively, there were significant improvements noted postoperatively. The preoperative inflection point level was significantly lower in the lower LVEF group. Preoperative thoracic kyphosis was significantly larger in the lower tricuspid annular peak systolic velocity group.

Preoperative Malnutrition-Associated Spinal Malalignment with Patient-Reported Outcome Measures in Adult Spinal Deformity Surgery: A 2-Year Follow-Up Study.

Introduction: Malnutrition could lead to additional medical complications, and the prognostic nutrition index (PNI) is evaluated to assess the nutritional status of patients. However, the midterm postoperative outcomes of malnutrition in patients with adult spinal deformity (ASD) are unclear. This study aims to investigate postoperative midterm spinal alignment and patients' reported outcome measures (PROMs) in malnourished patients with ASD. Methods: This study recruited 303 ASD patients who underwent surgery. Adult patients ≥50 years old were categorized into the PNI <50 (L group) and the PNI ≥50 (H group) groups. Demographic data, medical complications, mechanical complications, radiographic parameters, Oswestry Disability Index (ODI), and Scoliosis Research Society-22 (SRS-22) were analyzed. Results: In this study, 303 patients participated, with 132 and 171 patients in the L and H groups, respectively. Significant differences were noted between the L and H groups in body mass index (22.5 vs. 23.6 kg/m2, p=0.011), autoimmune disease (9.8% vs. 2.3%, p=0.005), and total number of medical complications (47.7% vs. 33.3%, p=0.011). The T1 slope was significantly higher in the L group than in the H group preoperatively (36.5 vs. 32.8°, p=0.042). However, no significant differences were noted in mechanical complications, ODI, SRS-22 scores, or radiographic parameters 2 years postoperatively between the L and H groups, except for the sagittal vertical axis (73.1 vs. 55.7 mm, p=0.014). Conclusions: No significant difference was noted in the incidence of mechanical complications and PROMs 2 years postoperatively. Malnourished status was related to medical complications and global malalignment. However, good surgical outcomes can be expected even for malnourished patients.

Change in Line of Sight after Corrective Surgery of Adult Spinal Deformity Patients: A 2-Year Follow-up.

STUDY DESIGN: Cohort study. PURPOSE: There is currently no published study that focuses on the spinal corrective surgery effects with cranial parameters in adult spinal deformity (ASD) patients. It is an important factor to measure since it plays a critical role in maintaining the line of sight. The objective is to determine the change in cranial parameters using the slope of McGregor's line (McGS) after ASD surgery after 2 years of follow-up. OVERVIEW OF LITERATURE: A study concluded that cervical spine alignment (C2-C7 lordosis) is strongly affected by thoracic kyphosis (TK). Another study showed that patients with ascending gaze had significantly more thoracolumbar malalignment. METHODS: This retrospective study includes 295 corrective surgery patients with ASD. Subjects were divided into two groups after propensity age matching analysis: cranial malalignment (McGS <-8 or >13) and normal cranial alignment (-8≤ McGS ≤13). Lumbar lordosis (LL), pelvic tilt (PT), TK, cervical lordosis (CL), and sagittal vertical axis (SVA) were evaluated between the two groups. RESULTS: SVA (95-56 mm) and PT (34°-25°) decreased and LL (19°-41°) increased 2 years after surgery (p <0.05), but McGS (-1.1° to -0.5°) and CL (21°-19°) did not change. Conversely, in the group with cranial malalignment, SVA (120-64 mm), PT (35°-26°), and LL (12°-41°) showed similar results to the normal cranial parameter group 2 years after surgery, but in contrast, McGS (-13° to -2°) and CL (24°-18°) improved significantly. CONCLUSIONS: Severe ASD adversely affects to maintain horizontal gaze but can be improved by spinal corrective surgery.

Longer Screws Can Reduce the Stress on the Upper Instrumented Vertebra With Long Spinal Fusion Surgery: A Finite Element Analysis Study.

STUDY DESIGN: A finite element analysis study. OBJECTIVE: Of proximal junctional failure, upper instrumented vertebra (UIV) fracture can causes severe spinal cord injury. Previously, we reported that higher occupancy rate of pedicle screw (ORPS) at UIV prevented UIV fracture in adult spinal deformity surgery; we had not yet tested this finding using a biomechanical study. The purpose of present study was to measure the differences in loads on the UIV according to the length of PS and ORPS. METHODS: We designed an FE model of a lumbar spine (L1-S1) using FE software. The PS was set from L2 to S1 and connected the rod. The FE model simulated flexion (8 Nm) to investigate the loads at UIV (L2) according to the length of the PS. There were 5 screw lengths examined: 40 (ORPS 36.4%), 45 (48.5%), 50 (66.7%), 55 (81.8%), and 60 mm (93.9%). RESULTS: Stress with bending motion was likely to occur at the upper front edge of the vertebral body, the pedicles, and the screw insertion point. The maximum equivalent stress according to screw lengths of 40, 45, 50, 55, and 60 mm were 45.6, 37.2, 21.6, 13.3, and 14.8 MPa, respectively. The longer screw, the less stress was applied to UIV. No remarkable change was observed between the screw lengths of 55 and 60 mm. CONCLUSIONS: Increasing ORPS to 81.8% or more reduced the load on the UIV. To prevent UIV fracture, the PS length in the UIV should be more than ORPS 81.8%.

Measuring Muscle Activity in the Trunk, Pelvis, and Lower Limb Which Are Used to Maintain Standing Posture in Patients With Adult Spinal Deformity, With Focus on Muscles that Contract in the Compensatory Status.

STUDY DESIGN: Prospective single-center study. OBJECTIVE: This study aimed to investigate the muscle activity of the trunk, pelvis, and lower limb, which are used to maintain a standing posture in elderly patients with spinal deformities. We also elucidated the mechanism of compensation against spinal deformity in terms of muscle activity. METHODS: Any patient scheduled to undergo surgery for adult spinal deformity was included. Surface electromyography and radiography were performed preoperatively. The following four representative alignments were defined as compensations: 1. pelvic retroversion, 2. reduction in thoracic kyphosis, 3. hyperextension of the lumbosacral junction, and 4. knee flexion. Individual muscle activity was compared with and without compensation. The patients were stratified into three groups according to the severity of spinal compensation, and differences in muscle activity were compared. RESULTS: This study included 76 patients (7 men and 69 women, average age 69.4 years). Our results revealed that pelvic retroversion and knee flexion were compensations that required trunk muscle activity. In contrast, reduction of thoracic kyphosis and hyperextension of the lumbosacral junction did not require much trunk muscle activity. There was a significant difference in the muscle activity of the pelvis and lower limbs according to the severity of the deformity. CONCLUSIONS: In terms of muscle activity, compensation for regional alignment changes in the adjacent spine is economical. However, extra-spinal compensations, such as pelvic retroversion and knee flexion, are non-economical. According to compensation recruitment, the muscle activity of the pelvis and lower limbs increased with the severity of the spinal deformity.

Characteristics of pedicle screw misplacement using freehand technique in degenerative scoliosis surgery.

PURPOSE: This study aimed to estimate the accuracy of pedicle screw (PS) placement in degenerative scoliosis surgery, characterize a patient population with PS misplacement, and analyze the association between misplaced PS vector and lumbar coronal curve. METHODS: In this study, 122 patients (average age 68.6 years), who underwent corrective and decompression surgery, were selected retrospectively. PS accuracy was evaluated in the thoracic to lumbar spine. We identified characteristics of misplacement in each patient. Screw positions were categorized into grade A, entirely in the pedicle; grade B, < 2 mm breach; grade C, 2-4 mm breach; and grade D, > 4 mm breach using postoperative computed tomography. RESULTS: The mean preoperative lumbar coronal curve was 32.3 ± 18.4°, and the number of fused vertebrae was 8.9 ± 2.8. A total of 2032 PS were categorized as follows: grade A, 1897 PS (93.3%); grade B, 67 (3.3%); grade C, 26 (1.3%); and grade D, 43 (2.1%). One PS (grade D), inserted at T5, needed surgery for removal due to neurological deficit. The misplacement group (grades C and D) had a significantly stronger lumbar coronal curve and apical vertebral rotation than the accuracy group (grades A and B). Misplaced PS vector (direction and degree) was significantly correlated with inserted vertebral rotation. Grade D misplacement was distributed mainly around the transitional vertebra of the lumbar curve. CONCLUSIONS: The accuracy of PS insertion in the thoracic to lumbar spine was high in DS surgery, but the need for care was highlighted in the transitional vertebra.

Perioperative lumbar subarachnoid drainage could not prevent postoperative CSF leakage after spinal cord tumor resection using an artificial dura mater.

BACKGROUND: Cerebrospinal fluid (CSF) leakage occurs in patients who undergo dural repair using artificial dura mater. This study aimed to determine if perioperative lumbar subarachnoid drainage could reduce the incidence of postoperative CSF leakage in cases of dural repair using artificial dura mater. METHODS: We retrospectively analyzed 84 patients (41 men, 43 women; mean age, 52.2 ± 20.1 years) who underwent intradural spinal cord tumor resection and dural repair using artificial dura mater. These patients were divided according to whether they underwent perioperative lumbar subarachnoid drainage (39 patients: D group) or had no drainage (45 patients: ND group). The incidence of radiographic and symptomatic CSF leakage as well as baseline characteristics and operative data were compared between the two groups. RESULTS: Radiographic CSF leakage was observed in 21 patients (25.0%), including 10 (25.6%) in the D group and 11 (24.4%) in the ND group. Symptomatic CSF leakage was observed in 12 patients (14.2%), including six (15,4%) in the D group and 11 (13.3%) in the ND group. There were no significant differences in the incidence of subcutaneous CSF accumulation and symptomatic CSF leakage between the two groups. In cases with symptomatic CSF leakage, the onset time of CSF leakage tended to be earlier (5.7 days vs 15.7 days), and the treatment period tended to be longer (5.8 weeks vs 2.8 weeks) in the ND group than in the D group. CONCLUSIONS: Perioperative lumbar subarachnoid drainage did not reduce the incidence of either radiographic or symptomatic CSF leakage. However, it might shorten the treatment period and reduce refractory CSF leakage, which requires multiple treatments over a long period.

Preoperative Less Right Shoulder Elevation Had a Higher Risk of Postoperative Shoulder Imbalance When Main Thoracic Curve Shows Higher Correction Regardless of the Upper Instrumented Vertebra Level for Patients with Adolescent Idiopathic Scoliosis Lenke Type 1.

STUDY DESIGN: This is a retrospective study. PURPOSE: This study aimed to investigate the incidence of and risk factors for postoperative shoulder imbalance (PSI) in patients with Lenke type 1. OVERVIEW OF LITERATURE: PSI is a complication resulting in poor self-image and satisfaction in adolescent idiopathic scoliosis (AIS) patients. METHODS: We examined the data of AIS patients with Lenke type 1 curves who underwent posterior fusion surgery in a retrospective manner. PSI was defined as a 2-year postoperative absolute radiographic shoulder height (RSH) of ≥2 cm. Patients were divided into two groups based on the presence of PSI and the level of their upper instrumented vertebra (UIV) (UIV at T2 or T3 [U-UIV] or UIV below T3 [L-UIV]). The radiographic parameters and clinical outcomes were compared, and the cutoff values of risk factors were identified by multivariate analysis. RESULTS: Of 104 patients, 21 (20.2%) had left shoulder elevation PSI. The PSI group had a significantly greater preoperative RSH (-5.1 mm vs. -14.3 mm) and main thoracic (MT) curve correction rate (77.3% vs. 69.1%) than the non-PSI group. The PSI incidence did not differ between the U-UIV and L-UIV groups. Multivariate analysis identified preoperative RSH and the MT curve correction rate as independent risk factors for PSI. The receiver operating characteristic curve analysis identified the preoperative RSH cutoff value as -6.5 mm and MT curve correction rate cutoff value as 76.9%. CONCLUSIONS: Even in AIS patients with Lenke type 1 curves, the incidence of PSI was relatively high (20.2%). Patients with preoperative lower right shoulder elevation (i.e., RSH >-6.5 mm) had a higher risk of PSI regardless of UIV level when the MT curve showed a higher correction rate (i.e., correction rate >76.9%).

Risk Factors for Cervical Deformity After Posterior Cervical Decompression Surgery: A Multicenter Study.

STUDY DESIGN: Retrospective multicenter study. OBJECTIVE: Posterior decompression surgery for cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) is a common surgery; however, it can cause postoperative cervical deformity (CD). The purpose of this study was to investigate the risk factors for CD. METHODS: The participants were 193 patients underwent laminoplasty or laminectomy for CSM or OPLL. CD was defined as a C2-7 sagittal vertical axis (SVA) ≥ 40 mm or a cervical lordosis angle (CL) ≤ -10°. The participants were divided into 2 groups: NCD (without CD before surgery), CD (with CD before surgery). NCD group was divided based on the presence of CD 1 year after surgery as follows: postoperative CD (PCD) and no PCD (NPCD). RESULTS: There were 153 patients (NCD), 40 (CD), 126 (NPCD), and 27 (PCD). There was significant difference in the number of decompressed lamina (NPCD: PCD = 4.1:4.5), the presence of C2 decompression (2: 11%), and C5 palsy (0: 11%). The risk factors for onset of CD, PCD, and CL ≤ -10° as assessed by multiple logistic regression analysis were preoperative C2-7 SVA ≥ 30 mm (odds ratio [OR]: 19.0), decompression of C2 or C7 lamina (OR 3.1), and preoperative CL ≤ 2° (OR 42.0), respectively. CONCLUSIONS: To prevent postoperative CD, it is important to avoid decompression of the C2 or C7 lamina. Moreover, in case with C2-7 SVA ≥ 30 mm or CL ≤ 2° before surgery, it is important to explain the risks and consider adding fusion surgery.

Clinical Outcomes and Complications of Corrective Fusion Surgery Down to L4, L5, and the Pelvis for Adult Scoliosis in Patients Younger than 50 Years.

Introduction: Corrective fusion for adult scoliosis often requires fusion from the thoracic spine to the lower lumbar spine or pelvis. However, it is often difficult to determine the lowest instrumented vertebrae (LIV), especially in younger patients. The purpose of this study was to summarize the clinical outcomes and revision surgery rates after corrective fusion for adult scoliosis at different LIV levels in patients under 50 years of age. Methods: We retrospectively analyzed 25 patients with adult scoliosis (mean age, 38 years; mean follow-up, 65 months) who underwent corrective fusion from the thoracic spine to L4, L5, or pelvis between 2010 and 2018. Preoperative and at least 2 years' postoperative radiographic parameters, patient-reported outcomes (Scoliosis Research Society-22r [SRS-22r]), mechanical complications, and revision surgery were investigated, and comparisons were made between two groups: the L4 and L5 (L) group (n=14) and the pelvic group (n=11). Results: Both groups showed a significant improvement in the SRS-22r domains of Self-image and Subtotal postoperatively compared with the baseline (P<0.05). The incidence of rod fracture was significantly higher in the pelvic group (5 patients, 45%) than in the L group (0 patients, 0%) (P=0.001). In addition, revision surgery was performed five times in 4 patients (36%) in the pelvic group compared with 0 in the L group (P=0.068). Conclusions: In the L group, clinical outcomes improved in the medium term, with no patients requiring revision surgery. In the pelvic group, the rod fracture rate was higher, but the clinical outcomes improved.

Revision Surgery Due to Proximal Junctional Failure and Rod Fracture in Adult Deformity Surgery at a Single Institution in Japan.

Introduction: Proximal junctional failure (PJF) and rod fracture (RF) are the primary reasons for revision surgery after a long corrective fusion for the adult spinal deformity (ASD). However, many recent studies on ASD are multicenter studies from the US and European racial characteristics may differ from those of Asians. Therefore, the risk factors for revision surgery because of PJF and RF after ASD surgery were evaluated in Japanese patients. Methods: Patients with ASD who underwent corrective surgery from the thoracic vertebrae to the ilium at the authors' institution were reviewed. Demographic, surgical, and radiographic parameters were included in the analysis. Univariate and multivariate regression models were used to analyze the risk factors for PJF and RF. Results: Two hundred and fifty-nine patients were included in the study. A total of 73 patients (28.1%) required revision surgery because of mechanical complications and 15 patients (5.7%) required revision surgery because of PJF on average 380 days after surgery. In PJF cases, body mass index (BMI) and pelvic tilt were significantly higher (p=0.01, p=0.048, respectively). BMI was an independent risk factor for revision owing to PJF (odds ratio [OR], 1.16; p=0.013). A total of 49 patients (18.9%) required revision owing to RF on average 867 days after surgery. Three-column osteotomy (p<0.001), significant blood loss (p=0.048), number of fusion segments (p=0.023), absence of lateral lumbar interbody fusion (p<0.001), and sagittal imbalance (p=0.033) were risk factors for revision surgery owing to RF in the univariate analysis. Three-column osteotomy (OR 4.41; p<0.001) and number of fusion segments (OR 1.21; p<0.009) were independent factors for revision surgery owing to RF. Conclusions: PJF occurred in a relatively early phase (approximately 1 year) after surgery in patients with ASD with high BMI. Conversely, RF occurred approximately 2.5 years after surgery in three-column osteotomy and spinal fusion cases that involvedlonger fusion range.

Revision Surgery for a Rod Fracture with Multirod Constructs Using a Posterior-Only Approach Following Surgery for Adult Spinal Deformity.

STUDY DESIGN: Single-center retrospective case series. PURPOSE: We aimed to evaluate the clinical results of revision surgery for a rod fracture using a posterior-only approach and determine the best procedure to prevent refracture in patients with adult spinal deformity (ASD). OVERVIEW OF LITERATURE: ASD affects the thoracolumbar spine and often requires surgical correction. However, surgery for extensive spinal fusion causes rod fracture, a major mechanical complication. Few studies have described the treatment methods for rod fractures. Furthermore, the clinical outcomes of revision surgery for rod fractures in patients with ASD are currently unclear. METHODS: We retrospectively reviewed the medical records of 404 patients who underwent corrective fusion surgery for ASD with a minimum 2-year follow-up. We studied cases of reoperation for postoperative rod fractures and investigated surgical procedure, intraoperative findings, clinical course, and rod refracture following revision surgery. RESULTS: Rod fracture was observed in 88 patients (21.8%). Fifty-three patients (average age, 68.3 years; average blood loss, 502.2 mL [% estimated blood volume=16.4%]; and operation time, 203.3 minutes) who suffered from a rod fracture at an average of 28.3 months after the primary operation underwent reoperation. Surgical invasiveness had no significant differences in total or partial rod replacement; however, the procedures with and without an anterior bone graft significantly differed. The replaced rod refractured at an average of 35.3 months after the revision surgery of five patients. The rod also refractured at a level outside multiple rods in two patients and with traumatic episodes in three patients. Three patients had bone grafts in the anterior column. CONCLUSIONS: Revision surgery involving a multirod with a posterior-only approach for a rod fracture that occurred after ASD was performed successfully. Bone grafting in the anterior column is unnecessary for patients without massive bone defects.

Incidence and Predictors of Postoperative Kyphotic Deformity after Thoracic Spinal Cord Tumor Resection.

INTRODUCTION: Kyphotic deformity is common after spinal tumor resection surgery. An adequate field of view is needed to resect the spinal cord tumor, and, in some cases, the facet joint must be removed during laminectomy, and fixation may be performed simultaneously. In this study, we investigated the incidence of postoperative deformity after spinal tumor resection and the factors associated with postoperative deformity. METHODS: We retrospectively analyzed patients who underwent thoracic spinal cord tumor resection at a single institution between 2010 and 2017 and were followed up for at least 24 months after surgery. Fifty percent or more of the facet joint was removed during the laminectomy, and fixation was performed simultaneously. Patients were divided into two groups, with and without kyphotic deformity. Patient demographic characteristics (age at surgery and gender), whether they underwent primary surgery or reoperation, tumor level, pathological type, and surgical method were compared. Multiple linear regression analysis was performed to identify independent predictors of kyphotic deformity. RESULTS: Thirty-one patients were found to be eligible. Thirteen patients had intramedullary spinal cord tumors. Laminectomy was performed in 52% (N=16), laminoplasty in 6% (N=2), and laminectomy and/or laminoplasty combined with fusion in 42% (N=13) of the patients. During a mean follow-up period of 66.8 months, 12 (39%) patients had postoperative kyphosis deformities, of which one patient (3%, a 12-year-old girl who underwent combined postoperative radiation therapy) underwent kyphosis correction surgery three years after surgery. The number of laminectomies was independently associated with kyphotic deformity. CONCLUSIONS: Although kyphotic deformity after spinal tumor surgery was observed in about 39% of the patients, corrective surgery was rarely required due to the progression of the deformity. The high number of laminectomies is a risk factor for postoperative kyphosis, and prophylactic fixation may be considered in cases of multiple laminectomies.

Clinical Outcomes of Corrective Fusion Surgery From the Thoracic Spine to the Pelvis for Adult Spinal Deformity at 1, 2, and 5 years Postoperatively.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To investigate whether patient-reported outcomes (PROs) were consistent at 2 and 5 years after corrective fusion surgery from the thoracic spine to the pelvis in patients with adult spinal deformity (ASD) and to analyze whether revision surgery affected long-term outcomes. SUMMARY OF BACKGROUND DATA: PROs up to 2 years after corrective surgeries for ASD have been well-studied, but there are few reports of mid- to long-term results. METHODS: We retrospectively analyzed patients with ASD who underwent corrective fusion surgery from the thoracic spine to the pelvis between 2010 and 2015. We investigated radiographic parameters and PROs (Scoliosis Research Society 22r [SRS-22r], Oswestry Disability Index [ODI]) preoperatively and at 1, 2, and 5 years postoperatively, and the correlations between PROs at these time points. We also compared changes in PROs at 5 years in patients who underwent revision surgery and those who did not. RESULTS: A total of 131 patients who underwent corrective fusion surgery from the thoracic spine to the pelvis were analyzed. The PROs at 1 and 5 years after surgery showed significant correlations in all SRS-22r domains (function [r  = 0.620], pain [r  = 0.577], self-image [r  = 0.563], mental health [r  = 0.589], subtotal [r  = 0.663], and ODI [r  = 0.654]). The PROs at 2 and 5 years after surgery showed significantly strong correlations in all domains (function [r  = 0.715], pain [r  = 0.678], self-image [r  = 0.653], mental health [r  = 0.675], subtotal [r  = 0.741], and ODI [r  = 0.746]). There were no significant differences in the change in PROs at 5 years in any domain in patients who underwent revision surgery (all P  > 0.05). CONCLUSION: One-year postoperative PROs improved significantly. Two-year PROs correlated strongly with 5-year postoperative PROs, indicating that 2-year PROs can predict longer term outcomes. The need for revision surgery did not influence the mid- to long-term clinical outcomes of corrective fusion surgery for ASD.Level of Evidence: 3.

Selective Angiography to Detect Anterior Spinal Artery Stenosis in Thoracic Ossification of the Posterior Longitudinal Ligament.

STUDY DESIGN: Single-center prospective study. PURPOSE: To investigate anterior spinal artery (ASA) status using preoperative selective angiography in patients undergoing surgery for thoracic ossification of the posterior longitudinal ligament (T-OPLL). OVERVIEW OF LITERATURE: Surgery for T-OPLL has a high risk of neurological complications, which might be associated with insufficient spinal cord blood flow. METHODS: This study prospectively examined nine T-OPLL patients who underwent posterior thoracic decompression with kyphosis correction and instrumented fusion at Hamamatsu University School of Medicine between 2017 and 2019. All underwent preoperative selective angiography to detect and evaluate the Adamkiewicz artery and ASA. Intraoperative neuromonitoring and Doppler ultrasonography were performed to analyze neurological complications and spinal cord blood flow. RESULTS: All nine patients showed ASA stenosis in the area of T-OPLL. In all patients, the Adamkiewicz artery was located between T7 and L2 and the area of ASA stenosis corresponded to the level of T-OPLL and greatest spinal cord compression; intraoperative Doppler ultrasonography confirmed the ASA defect at the same spinal level. The number of spinal levels from the Adamkiewicz artery to the most compressive OPLL lesion was greater in the two patients who developed postoperative neurological deficit compared to those who did not (5.5 vs. 2.3, p=0.014). CONCLUSIONS: This is the first study to report detection of ASA stenosis in patients with T-OPLL. Maintaining spinal cord blood flow is important in these patients to avoid neurological deterioration.

Factors Affecting Operation Duration in Posterior Spinal Fusion (PSF) Using Dual Attending Surgeon Strategy Among Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) Patients.

STUDY DESIGN: This was a retrospective study. SUMMARY OF BACKGROUND DATA: Prolonged operation duration in adolescent idiopathic scoliosis (AIS) surgery was associated with increased perioperative complications. However, the factors affecting operation duration in AIS surgery were unknown. OBJECTIVE: The aim of the study was to investigate the factors affecting operation duration in posterior spinal fusion (PSF) surgery using a dual attending surgeon strategy among Lenke 1 and 2 AIS patients. METHODS: In all, 260 AIS patients with Lenke 1 and 2 curves who underwent PSF were retrospectively reviewed. Preoperative and intraoperative factors affecting operation duration such as age, sex, height, weight, body mass index, Risser grade, Lenke subtypes, number of fusion level, number of screws, screw density, wound length, upper and lowest instrumented vertebrae level, preoperative Cobb angle, and flexibility of the major curve were assessed using univariate and multivariate linear regression analyses. Independent factors were determined when P-value <0.05. RESULTS: The mean operation duration was 122.2±28.6 minutes. Significant independent factors affecting operation duration in PSF among Lenke 1 and 2 AIS patients were Lenke 2 subtypes (ß=8.86, P=0.008), number of screws (ß=7.01, P<0.001), wound length (ß=1.14, P=0.009), and flexibility of the major curve (ß=-0.25, P=0.005). The overall model fit was R2=0.525. Operation duration can be predicted using the formula: (8.86×Lenke subtypes)+(7.01×number of screws)+(1.14×wound length)-(0.25×flexibility)-0.54, where Lenke 2=1 and Lenke 1=0. CONCLUSION: The factors affecting operation duration in PSF among Lenke 1 and 2 AIS patients were Lenke 2 curves, number of screws, wound length, and curve flexibility. The knowledge of these factors enables the spinal deformity surgeons to plan and estimate the operation duration before AIS surgery.

The Effect of Preoperative Nutritional Intervention for Adult Spinal Deformity Patients.

STUDY DESIGN: A prospective nutritional intervention study for adult spinal deformity (ASD) patients. OBJECTIVE: To investigate how a nutritional intervention affects the incidence of postoperative medical complications and the nutritional status. SUMMARY OF BACKGROUND DATA: The medical complication rate in ASD surgery is very high, and one risk factor is malnutrition. Nutritional intervention may improve the patient's nutritional status and reduce risk, but this is unexplored regarding ASD surgery. METHODS: Malnourished patients (i.e., a prognostic nutritional index [PNI] score of <50) scheduled for surgery after November 2018 (Group I) received nutritional intervention consisting of nutritional guidance and supplements on the surgery day. The medical complication rates between Group I and Group NI (malnourished patients who underwent surgery between January 2014 and October 2018; historical controls) were evaluated. The nutritional status courses of Group I and Group NI2 (patients who did not participate in nutritional intervention after November 2018) were assessed. RESULTS: Group I had 24 patients in (mean age, 70 yr), and Group NI had 69 patients (mean age, 68 yr). The mean intervention duration was 41 days. The preoperative PNI score did not differ between the groups, but there was a significant difference in medical complications incidences (Group I: 25%; Group NI: 53.6%; P = 0.015). The nutritional status significantly deteriorated in Group I (PNI: 47-45; P = 0.011) and Group NI2 (61 patients; mean age, 68 yr; PNI: 52-48; P = 0.000), but the PNI changes were significantly smaller in Group I (ΔPNI: Group I: -1.9, Group NI 2: -3.5; P = 0.027). CONCLUSION: Nutritional intervention with guidance and supplements reduced postoperative medical complications in malnourished patients. The nutritional status of ASD patients requiring surgery also naturally worsened, suggesting that ASD may contribute to malnutrition. Nutritional intervention may reduce the nutritional status deterioration.Level of Evidence: 3.

Long-acting erythropoiesis-stimulating agent (ESA) induces physiological erythropoiesis via improvement of iron availability.

PURPOSE: Previous studies reported that the long-acting erythropoiesis-stimulating agent (ESA) significantly suppresses the expression of hepcidin, which regulates iron availability. In this study, we compared the iron availability for erythropoiesis between short and long-acting ESA over a long period. METHODS: We enrolled 69 hemodialysis patients in this study. All patients were treated with short-acting ESA (epoetin-α or epoetin-ß) for the first 30 months. Then, all patients switched to long-acting ESA (continuous erythropoietin receptor activator-methoxy polyethylene glycol-epoetin beta) for the next 30 months. We measured their blood levels of Hb, ferritin, iron, total iron-binding capacity, intact-parathyroid hormone, calcium, phosphate, albumin, and highly sensitive CRP level. RESULTS: There was no significant change in the dose of short or long-acting ESA during the study period. Compared with the short-acting ESA period, the mean hemoglobin (Hb) and transferrin saturation levels were significantly increased in the long-acting ESA period (from 10.3 ± 0.2 to 10.6 ± 0.3 g/dL). On the other hand, the mean serum ferritin level (from 72 ± 22.2 to 56.3 ± 14 ng/mL) and the dose of IV iron (from 108 ± 63 to 53 ± 27 mg/month) were significantly decreased in the long-acting ESA period. CONCLUSION: In this study, we found that anemia treatment with long-acting ESA attenuated the iron utilization for erythropoiesis and maintained target Hb levels without requiring a higher dose of IV iron or ESA.