Analysis of the risk factors for increasing cervical sagittal vertical axis after cervical laminoplasty for cervical spondylotic myelopathy.

INTRODUCTION: The cervical sagittal vertical axis (cSVA) as another aspect of cervical alignment been recognized as one of the important factors affecting the pain and disability outcomes of cervical spine surgery. The purpose of the present study was to analyze the risk factors for increasing cSVA after cervical laminoplasty for cervical spondylotic myelopathy (CSM). MATERIALS AND METHODS: This retrospective study included 110 consecutive patients (68 males and 42 females, average age 72.6 years) who underwent laminoplasty for CSM between January 2007 and June 2018. We recorded the operative time, blood loss, Japanese Orthopaedic Association (JOA) score and the recovery rate. Radiological measurements were performed to analyze the following parameters: pre- and 1-year postoperative McGregor's slope (McGS), occiput to C2 Cobb angle (O-C2 angle), C2-C7 Cobb angle (C2-7 angle), T1-slope (T1S), C2-7 SVA (cSVA) and calculated the change (Δ). Patients were divided into two groups according to whether ΔcSVA was positive or negative. We also used Spearman's correlation coefficient and multiple regression analysis. RESULTS: ΔC2-7 angle, ΔT1S-preoperative C2-7 angle, ΔO-C2 angle were different between the two groups significantly. Correlation analysis between the ΔcSVA and the various sagittal parameters showed some independent explanatory factors including the ΔC2-7 angle (r = - 0.25, p = 0.010), T1S-preoperative C2-7 angle (r = - 0.28, p = 0.004), postoperative O-C2 angle (r = 0.26, p = 0.007), ΔO-C2 angle (r = 0.37, p = 0.001). Multiple regression analysis revealed that ΔcSVA was associated with the T1S-preoperative C2-7 angle (ß = - 0.25, p = 0.034) and ΔO-C2 angle (ß = 0.32, p = 0.001). CONCLUSIONS: The imbalance between T1S and preoperative C2-7 angle influences the change of cSVA after cervical laminoplasty. If cSVA increases postoperatively, the O-C2 angle increases to compensate and maintain the horizontal gaze.

The fibrinogen levels on admission is a predictive marker of the contrast extravasation on enhanced computed tomography in sacral fracture.

ABSTRACT: Sacral fracture is the most frequent posterior injury among unstable pelvic ring fractures and is prone to massive hemorrhage and hemodynamic instability. Contrast extravasation (CE) on computed tomography (CT) is widely used as an indicator of significant arterial bleeding. However, while CE is effective to detect significant arterial bleeding but negative result cannot completely rule out massive bleeding. Therefore, additional factors help to compensate CE for the prediction of early hemodynamically unstable condition.We evaluated the risk factors that predict CE on enhanced computed CT in patients with sacral fractures. Patients were classified into 2 groups: CE positive on enhanced CT of the pelvis [CE(+)] and CE negative [CE(-)]. We compared age, sex, injury severity score (ISS), systolic blood pressure (sBP), type of sacral fracture based on Denis classification, platelet (PLT), base excess, lactate, prothrombin time-international normalized ratio, hemoglobin (Hb), activated partial thromboplastin time, D-dimer, and fibrinogen between the 2 groups.A total of 82 patients were treated for sacral fracture, of whom 69 patients were enrolled. There were 17 patients (10 men and 7 women) in CE(+) and 52 patients (28 men and 24 women) in CE(-). Age, ISS, and blood transfusion within 24 hours were significantly higher in the CE(+) group than in the CE(-) group (P = .023, P < .001, P < .001). sBP, Hb, PLT, fibrinogen were significantly lower in the CE(+) group than in the CE(-) group (P < .001, P < .001, P < .001, P < .001). D-dimer and lactate were higher in the CE(+) group than in the CE(-) group (P = .036, P < .001) with significant differences. On multivariate analysis, the level of fibrinogen was an independent predictor of CE(+). The area under the curve value for fibrinogen was 0.88, and the optimal cut-off value for prediction was 199 mg/dL.The fibrinogen levels on admission can predict contrast extravasation on enhanced CT in patients with sacral fractures. The optimal cut-off value of fibrinogen for CE(+) prediction in sacral fracture was 199 mg/dL. The use of fibrinogen to predict CE(+) could lead to prompt and effective treatment of active arterial hemorrhage in sacral fracture.

Analysis of reciprocal changes in upper cervical profiles after posterior spinal fusion with the simultaneous double rod rotation technique for adolescent idiopathic scoliosis.

BACKGROUND: The relationship between postoperative change of cervical lordotic alignment and restoration of thoracic kyphosis with adolescent idiopathic scoliosis (AIS) is still controversial. We investigated reciprocal changes in the sagittal profiles of the upper and middle-lower cervical spinal segments after posterior spinal fusion with the simultaneous double rod rotation technique (SDRRT) for AIS. HYPOTHESIS: Occiput-C2 and C2-C7 sagittal profiles of patients with AIS could change significantly after surgical adequate increase of thoracic kyphosis with SDRRT. PATIENTS AND METHODS: Twenty-seven consecutive patients with AIS treated with the SDRRT were retrospectively reviewed. We investigated the following parameters preoperatively, postoperatively, and at the 2-year follow-up: the Cobb angles of main thoracic curves; C7 sagittal vertical axis; thoracic kyphosis (TK) from T5 to T12; lumbar lordosis from L1 to S1; chin-brow vertical angle; McGregor's slope; occiput to C2 Cobb angle (O-C2angle); C2-C7 Cobb angle (C2-C7angle); T1-slope; and C2-C7 sagittal vertical axis. Additionally, the Scoliosis Research Society questionnaire was completed preoperatively and at the 2-year follow-up. Patients were categorized according to preoperative TK (T5-T12) into hypokyphotic (TK<20°) and normo-hyperkyphotic (TK≧20°) groups. To assess the effect of corrective surgery on sagittal profiles, we investigated correlations among the changes in sagittal parameters. RESULTS: The mean preoperative TK was 6.1±3.7° in the Hypokyphotic group and 23.5±4.7° in the Normo-hyperkyphotic group (p<0.001), which was significantly improved postoperatively (22.3±4.4° and 26.1±2.6°, respectively; p=0.02) and at the 2-year follow-up (23.0±6.3° and 26.8±5.0°, respectively; p=0.04). The mean preoperative C2-C7angle reflected kyphosis (7.4±9.8°) in the Hypokyphotic group, and, in contrast, lordosis (-8.8±6.8°) in the Normo-hyperkyphotic group (p<0.001), which improved toward greater lordosis postoperatively (-3.7±5.8° and -14.8±5.1°, respectively; p<0.001) and at the 2-year follow-up (-5.1±4.4° and -15.3±6.4°, respectively; p<0.001). On the other hand, the mean preoperative O-C2angle was -20.5±6.5° in the Hypokyphotic group and -13.1±2.8° in the Normo-hyperkyphotic group (p=0.002), which was significantly changed postoperatively (-12.6±6.4° and -7.7±4.3°, respectively; p=0.04) and at the 2-year follow-up (-13.1±6.3° and -7.9±4.3°, respectively; p=0.04). ΔC2-C7 was negatively correlated with ΔT5-T12 (r=-0.298) and ΔO-C2angle (r=-0.332). DISCUSSION: Lordotic reciprocal alignment changes in the C2-C7angle can occur after adequate restoration of TK. The O-C2angle compensates the C2-C7angle for a maintained horizontal gaze. O-C2 and C2-C7 sagittal profiles of patients with AIS changed significantly after corrective surgery with SDRRT. LEVEL OF EVIDENCE: IV, Case-series.

Analysis of the reciprocal changes in upper cervical profile and the risk factors for increasing cervical sagittal vertical axis after laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine.

OBJECTIVE: The purpose of this study was to elucidate the reciprocal changes in the upper cervical profile and the risk factors for increasing cervical sagittal vertical axis (cSVA) after laminoplasty for ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. PATIENTS AND METHODS: This retrospective study included thirty-nine consecutive patients (30 men and 9 women) with cervical OPLL who underwent cervical laminoplasty. We recorded the operative time, blood loss, Japanese Orthopaedic Association (JOA) score recovery rate. Radiological measurements were performed to analyze the following parameters: pre and 1- year postoperative chin-brow vertical angle (CBVA), McGregor's slope (McGS), occiput to C2 Cobb angle (O-C2 angle), C2-C7 Cobb angle (C2-C7 angle), T1-slope (T1S), C2-C7 sagittal vertical axis (cSVA) and calculated the change (Δ). Patients were divided into two groups according to ΔcSVA: positive (ΔcSVA ≥ 0) and negative (ΔcSVA < 0). RESULTS: Postoperative O-C2 angle (P = 0.028), ΔO-C2 angle (P = 0.019), ΔC2-C7 angle (P = 0.030) and T1S (P = 0.009) diff ;ered between the two groups. ΔcSVA showed a positive correlation with ΔO-C2 (R = 0.365, P = 0.022) and T1S (R = 0.472, P = 0.002). ΔO-C2 showed a positive correlation with T1S (R = 0.478, P = 0.002) and a negative correlation with ΔC2-C7 (R=-0.443, P = 0.005). ΔC2-C7 showed a negative correlation with T1S (R=-0.415, P = 0.009). Stepwise multiple linear regression analysis showed that ΔcSVA increased by 0.757 mm for each T1 slope and increased by 0.905 mm for each ΔMcGS. CONCLUSION: Increasing the lordosis in the O-C2 segment compensates for the loss of lordosis in the C2-C7 segment after cervical laminoplasty. Higher T1S is a risk factor for increasing cSVA after laminoplasty for OPLL of the cervical spine.

Fibrinogen level on admission is a predictive marker of the need for massive blood transfusion after pelvic fracture.

OBJECTIVE: This study aimed to evaluate the usefulness of coagulation biomarkers as predictors of the need for massive transfusion (MT) in patients with pelvic fractures. METHODS: Patients who were treated for pelvic fractures in our hospital were divided into 2 groups: MT and non-MT. MT was defined as the transfusion of packed red blood cells (PRBCs) ≧10 units caused by bleeding within 24 h after admission. We compared variables between two groups, including vital signs, the scoring system and blood sample test. Additionally, we performed a multiple logistic regression analysis and a receiver operating characteristic curve analysis to reveal which value was the most useful predictive marker for MT in patients with pelvic fracture. RESULTS: There were 22 patients in the MT group and 78 patients in the non-MT group. Patients in the MT group had significantly higher ISS than did those in the non-MT group. In contrast, the patients in the MT group had significantly lower RTS, TRISS Ps, sBP, Hb, lactate, BE, and Fbg levels. Lower sBP and Fbg levels were independent predictors for MT. The optimal cut-off values for sBP and Fbg levels were ≦109 mmHg and 193.0 mg/dL, respectively. CONCLUSIONS: The results of the study indicated that Fbg levels on admission can be an independent predictor of MT in patients with pelvic fractures. The optimal cut-off value of Fbg for MT prediction in this study was 193.0 mg/dL.

Analysis of computed tomography-based infra-acetabular morphometry to assess the feasibility of infra-acetabular screws.

INTRODUCTION: The number of pelvic fractures based on osteoporosis has been increasing. The infra-acetabular screw (IAS), which connected both osseous columns, is a safe method of screw placement going through the infra-acetabular corridor (IAC). However, the specifics of the anatomy of IAC have been far from completely understood, especially in the Asian population. The purpose of our study was to reveal the details of the IAC using computed tomography (CT) data. MATERIALS AND METHODS: Traumatized in-patients having pelvic CT scans from 2014 to 2016 were enrolled. Pediatric and adult patients with pelvic fractures and hip prostheses were excluded. The male/female ratio and distribution of patients' age were equalized manually; 40 male and 40 female patients were included. The IAC was measured on the plane of the inlet view (25° caudal) in multi-planar reconstructed CT images. MEASUREMENTS: infra-acetabular diameter (IAD), anterior-posterior length of the IAC (APL), length from the starting point of the IAC to the medial edge of the pelvis (LME), length from the starting point of the IAC to the top of the pubic symphysis (LPS), and tilting on inlet plate (TIP). RESULTS: Age was 59 ± 22 (mean ± SD). Height was 159 ± 11 cm, and body mass index (BMI) was 22.9 ± 4.1. IAD, APL, LME, LPS, and TIP was 4.0 ± 1.3 mm, 89.5 ± 7.1 mm, 8.7 ± 3.6 mm, 57.8 ± 4.8 mm, and 4.7 ± 5.2°, respectively. Over 20% of corridors (35 of 160) were not feasible for IAS placement, because of inadequate width (less than 3.0 mm). Nine corridors (5.6%) had curvature in IAC, which meant technically demanding to insert IAS. There was no difference in IAD between male and female patients, while APL, LME, LPS, and TIP had sex-related differences. CONCLUSIONS: Surgeons should pay attention to the fact that over 20% of IACs are not feasible for infra-acetabular screw placement even with the perfect reduction of fragments when treating acetabular fractures.

Cervical alignment after single-level anterior cervical corpectomy and fusion using autologous bone graft without spinal instrumentation for cervical pyogenic spondylitis.

BACKGROUND: Subsidence in anterior cervical corpectomy and fusion (ACCF) for cervical degenerative disease (CDD) are constantly observed during the postoperative course. Although kyphotic change of cervical alignment occurred frequently in cervical pyogenic spondylitis (CPS) postoperatively, studies on the postoperative change in segmental angle for CPS are limited. This study aimed to analyze cervical alignment after single-level ACCF using autologous bone graft without spinal instrumentation for CPS compared with that for CDD. METHODS: Six patients underwent single-level ACCF using autologous bone graft without spinal instrumentation for CPS. The control group included 18 age-matched patients who underwent single-level ACCF using autologous bone graft for CDD without spinal instrumentation for the same duration. Cervical and lateral plain radiographs and computed tomography scans were taken. The Frankel classification was used to assess the neurological status preoperatively, postoperatively, and at 2-year follow-up for CPS. RESULTS: At 2-year follow-up, the average segmental angle at the fusion level was - 12.2° ± 6.9° for CPS and - 5.2° ± 7.6° for CDD (p = 0.04). Changes in segmental angle at the fusion level were - 7.2 ± 9.0° for CPS and - 1.1° ± 7.1° for CDD (p = 0.02). At 2-year follow-up, the average anterior segmental fusion height was 23.4 ± 1.7 mm for CPS and 29.1 ± 5.1 mm for CDD (p < 0.001). At 2-year follow-up, bone fusion in the CPS group was classified as grade 5 (complete fusion) in 4 patients (66.7%) and grade 4 (probable fusion) in 2 (33.3%). In the CDD group, it was grade 5 in 13 patients (72.2%) and grade 4 in 5 patients (27.8%). Overall, both groups achieved 100% bone fusion rate. The Frankel classification in all CPS cases improved or leveled off. CONCLUSION: Progression of segmental kyphosis angle and subsidence of graft bone were observed postoperatively on all CPS cases. However, the neurological recovery and bone union were satisfactory.

Enhancement of the effects of intermittent parathyroid hormone (1-34) by bone morphogenetic protein in a rat femoral open fracture model.

BACKGROUND: Nonunion in cases of open fracture is common. Both bone morphogenetic protein 2 (BMP-2) and parathyroid hormone (PTH) have been used to enhance bone healing. We investigated the combination of BMP-2 and PTH and examined the effects on a rat model of open femoral fractures. METHODS: Group I (n = 11) was implanted with control carrier. Group II (n = 12) was implanted with carrier containing 1 µg of recombinant human BMP-2 (rhBMP-2). Group III (n = 12) was implanted with carrier alone, followed by injections of PTH 1-34. Group IV (n = 11) was implanted with carrier containing 1 µg of rhBMP-2, followed by injections of PTH 1-34. Group V (n = 11) was implanted with carrier containing 10 µg of rhBMP-2. Group VI (n = 11) was implanted with carrier containing 10 µg of rhBMP-2, followed by injections of PTH 1-34. Rats were euthanized after 8 weeks, and their fractured femurs were explanted and assessed by manual palpation, radiographs, micro-computerized tomography, and histological analysis. RESULTS: Manual palpation tests showed that the fusion rates of groups III (66.7%), IV (63.6%), V (81.8%), and VI (81.8%) were considerably higher than those of group I. Groups V and VI had higher radiographic scores compared to group I. Micro-CT analysis revealed enhanced bone marrow density expressed as bone volume/tissue volume in groups V (61.88 ± 3.16%) and VI (71.14 ± 3.89%) versus group I (58.26 ± 1.86%). A histological analysis indicated that group VI had enhanced remodeling. CONCLUSION: The combination of abundant rhBMP-2 and PTH enhanced bone healing and remodeling of newly formed bone in a rat femoral open fracture model.

The position of the spinal cord relative to the vertebrae in adolescent idiopathic scoliosis.

We aimed to clarify the position of the spinal cord relative to the vertebra in patients with Lenke type 1 adolescent idiopathic scoliosis (AIS). In all, 35 patients with Lenke type 1 AIS who underwent posterior spinal fusion using a pedicle screw construct and preoperative computed tomography (CT) after myelography were recruited. The following radiological parameters were measured on preoperative CT myelography: spinal cord-vertebral (SV) angle, entry-spinal cord distance (ESD), ESD-X, ESD-Y, spinal cord-pedicle (SP) angle, and rotation angle (RAsag). The SV and SP angles were the smallest at T9 level, followed by T8 and T7 levels, and tended to increase cranially and caudally. The ESD was the shortest at T9 level, followed by T8 and T10 levels. The ESD-X was the smallest at T9 level, followed by T8 level, while the ESD-Y was the smallest at T10 level, followed by T9 and T8 levels. Mean RAsag increased from T4 to T9 levels and decreased from T9 to T12 levels. The ESD was significantly negatively correlated to RAsag. Among all apical vertebrae, the SV and SP angles were negatively correlated to Cobb angle. The RAsag was positively correlated while the ESD was negatively correlated to the Cobb angle. The spinal cord is close to the vertebrae in the apical vertebral region and far from the vertebrae at the upper and lower thoracic vertebral levels in AIS. Therefore, the potential risk of spinal cord injury by pedicle screw is the highest in the apical vertebral region.

Effect of intraoperative position in single-level transforaminal lumbar interbody fusion at the L4/5 level on segmental and overall lumbar lordosis in patients with lumbar degenerative disease.

The purpose of this study was to investigate the effect of intraoperative positions in single-level (L4-5) transforaminal lumbar interbody fusion (TLIF) on segmental and overall lumbar lordosis (LL) in patients with lumbar degenerative disease. Thirty-eight consecutive patients who had undergone single-segment (L4-5) TLIF with 0° polyetheretherketone (PEEK) cage and pedicle screw fixation were evaluated. Twenty patients underwent surgery on the four-poster type frame with hip flexion at 30° (Group I) and 18 patients were operated on a Jackson spinal table to adjust their hip flexion to 0° (Group II). Preoperative standing, intraoperative prone, and postoperative standing lateral radiographs were obtained in each patient. The overall and segmental LL were analyzed according to the position in which the patients were placed for their operation and results compared between Groups I and II. Intraoperative intervertebral segmental LL at L4-5 and L5-S1 was increased in Group II than in Group I, whereas postoperative intervertebral segmental LL at L4-5 (fused level) was increased LL. In Group I intraoperative intervertebral segmental LL at L4-5 did not achieve sufficient lordosis, whereas postoperative intervertebral segmental LL at L3-4 was increased. The overall spinal alignment was unaffected by the decreased segmental LL in the fused level owing to the compensation of the upper adjacent segments. The more the hip was extended intraoperatively, the more the segmental lordosis increased in the lower lumbar spine. Thus, selecting the appropriate surgical table and hip position are very important. Underachievement of segmental lordosis leads to the acceleration of upper adjacent segment load.

Spinal epidural lipomatosis is associated with liver fat deposition and dysfunction.

OBJECTIVE: This study examined the association of spinal epidural lipomatosis (SEL) with liver fat deposition and any other liver dysfunction, except steroid involvement. PATIENTS AND METHODS: We analyzed 102 patients (62 men and 40 women; mean age 73.3 years) who underwent spinal magnetic resonance imaging (MRI), computed tomography (CT), and myelography for the diagnosis of lumbar spinal canal stenosis between January 2014 and June 2018. Additional data collected included height, weight, body mass index, blood test results (C-reactive protein, albumin, total bilirubin, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase [γ-GTP], total cholesterol, neutral fat, amylase, urea nitrogen, creatinine, estimated glomerular filtration rate, uric acid, platelets), the epidural fat-occupying ratio in each vertebra from L1/2 to L5/S1 on MRI, and liver CT values. RESULTS: In 30 cases, the average occupying ratio of epidural fat was ≥40% (SEL), and in 45 cases, liver CT values were <40 HU (fatty liver). Correlation analysis between average occupying ratio of epidural fat and various measurements showed liver CT value (r = -0.574, P <  0.001), body weight (r = 0.304, P =  0.002), γ-GTP (r = 0.370, P =  0.01), and uric acid (r = 0.201, P =  0.04) to be independent explanatory factors. Multivariate analysis revealed that SEL was associated with liver CT value (odds ratio 0.774, 95% confidence interval [CI] 0.689-0.871) and body weight (odds ratio 1.063, 95% CI 1.016-1.135). CONCLUSION: There was a strong correlation between epidural fat and liver fat deposits suggesting an association between SEL and systemic fat deposition.

Minimally invasive triangular osteosynthesis for highly unstable sacral fractures: Technical notes and preliminary clinical outcomes.

Triangular osteosynthesis involves unilateral L5 iliac posterior instrumentation combined with an iliosacral screw fixation. The aim of this study was to describe this procedure and report the preliminary clinical results in patients with unstable sacral fractures treated with minimally invasive triangular osteosynthesis (MITO). Between 2012 and 2017, 10 patients (6 men and 3 women, mean age, 50 ±â€Š23 years) with sacral fractures were treated with MITO and were followed up for a mean of 15.0 ±â€Š8.5 months in our institution. Classification of sacral fracture, operative time, intraoperative bleeding, timing of full weight bearing, bone union, complications, and clinical outcomes were investigated. Two cases were classified as Denis zone 1, 2 cases as zone 2, and 6 as zone 3. Four patients had Roy-Camille type 1 fracture and 2 patients had type 2. All patients underwent MITO, which involved bilateral lumbopelvic fixation and a uni/bilateral iliosacral screw with stab incisions for percutaneous fixation or central longitudinal incision. The operative time was a mean of 182 ±â€Š64 minutes, and the amount of intraoperative bleeding was a mean of 63 ±â€Š74 g. Full-weight bearing was initiated at a mean of 8.2 ±â€Š2.4 weeks. Eight fractures healed; 1 patient had pulmonary embolism and 1 had implant loosening. Based on Majeed score, 8 patients had "excellent" clinical outcomes, 1 patient had a "good" clinical outcome, and the other had a "fair" clinical outcome. MITO could be less invasive on the soft tissues and be a reliable procedure for bony union. It might provide sufficient stability to accelerate the commencement of post-operative rehabilitation, even in patients with highly unstable sacral fractures.

Effect of thoracic kyphosis formation and rotational correction by direct vertebral rotation after the simultaneous double rod rotation technique for idiopathic scoliosis.

OBJECTIVE: The objective of the present study was to evaluate the effect of thoracic kyphosis formation and rotational correction by direct vertebral rotation (DVR) after the simultaneous double-rod rotation technique (SDRRT) for idiopathic scoliosis (IS). PATIENTS AND METHODS: The present study included twelve patients with IS who received SDRRT (SDRRT group) and twelve patients with IS who received DVR after SDRRT (SDRRT + DVR group). We investigated the following parameters preoperatively, postoperatively, and at postoperative 2 years: Cobb angle (PT, MT, T/L, C7-CSVL, AVT, TK (T5-12), LL(L1-S1) RSH, the angle of rotation (RAsag), percent change of RAsag and SRS22 (at postoperative 2 years only). RESULTS: Preoperatively, the mean main thoracic curve was 58.9 ± 12.4° for the SDRRT group and 59.9 ± 16.0° for the SDRRT + DVR group, which was corrected to 14.6 ± 6.7° and 13.4 ± 4.9° postoperatively. and 14.9 ± 7.1° and 14.3 ± 4.1° at postoperative 2-year follow-up, respectively. Correction rates were 75.4 ± 10.4% and 77.2 ± 8.0 % postoperatively. Thoracic kyphosis increased postoperatively and at postoperative 2-year follow-up in both the SDRRT group and the SDRRT + DVR group. The mean preoperative TK was 11.4 ± 7.3° in the SDRRT group, and 12.8 ± 11.5° in the SDRRT + DVR group, which improved significantly to 24.8 ± 5.2° and 23.6 ± 3.5° postoperatively and 23.3 ± 3.9° and 24.2 ± 6.0° at postoperative 2-year follow-up, respectively. Correction of vertebral rotation as RAsag was significantly better in the SDRRT + DVR group than in the SDRRT group. The mean preoperative RAsag was 19.1 ± 6.7° in the SDRRT group, and 18.3 ± 7.5° in the SDRRT + DVR group, which improved to 13.3 ± 4.3° and 10.1 ± 2.9° postoperatively (P = 0.04) and 13.9 ± 4.0° and 10.6 ± 2.8° at postoperative 2-year follow-up (P = 0.02), respectively. CONCLUSION: DVR after SDRRT for idiopathic scoliosis allowed for rotation correction without compromising kyphosis formation.

Relationship of preoperative intramedullary MRI signal intensity and dynamic factors with surgical outcomes of laminoplasty for cervical ossification of the posterior longitudinal ligament.

OBJECTIVE: We aimed to analyze the relationship of preoperative signal intensity on magnetic resonance imaging (MRI) and dynamic factor with surgical outcomes of laminoplasty for cervical ossification of the posterior longitudinal ligament (OPLL). PATIENTS AND METHODS: We retrospectively reviewed the records of 29 patients (20 males and 9 females) who underwent double-door laminoplasty for cervical OPLL. T2-weighted MRI was performed preoperatively. To assess the high-signal changes of the spinal cord, signal intensity was classified as grade 0 (low signal, no changes), grade 1 (medium signal, mild changes), and grade 2 (bright signal, pronounced changes). The following factors were analyzed for their relationship with surgical outcome, expressed as the Japanese Orthopedic Association (JOA) score recovery rate: pre- and postoperative C2-C7 range of motion (ROM), segmental ROM, C2-C7 lordotic angle, and spinal cord occupying ratio, as well as disease duration. RESULTS: Disease duration was significantly longer in patients with pronounced high-signal changes on preoperative MRI (P < 0.05 for grade 2 vs. grade 1 or 0). The mean preoperative JOA score and JOA score recovery rate were significantly lower in patients with pronounced high-signal changes on preoperative MRI (P < 0.05 for grade 2 vs. grade 1 or 0). Preoperatively, segmental ROM was significantly smaller in patients with no MRI signal intensity changes (P < 0.05 for grade 0 vs. grade 1 or 2). Additionally, preoperative segmental ROM was negatively correlated with JOA score recovery rate (R=-0.470, P = 0.01) and positively correlated with high-signal changes on preoperative MRI (R = 0.460, P = 0.012). On multivariate analysis, preoperative segmental ROM was negatively associated with JOA score recovery rate (odds ratio, - 0.407; P = 0.046). CONCLUSION: Given its negative correlation with JOA score recovery rate and positive correlation with high-signal changes on preoperative MRI, higher preoperative segmental ROM may be associated with spinal cord damage due to repeated minor trauma, predicting poor surgical outcome of laminoplasty in cervical OPLL.

Relationship between vertebral morphology and the potential risk of spinal cord injury by pedicle screw in adolescent idiopathic scoliosis.

OBJECTIVE: We aimed to investigate the relative preoperative position of the spinal cord in AIS and explore the potential risk of spinal cord injury from placement of pedicle screws. PATIENTS AND METHODS: Twenty-seven patients with a mean age of 15 ±â€¯1.8 years (range, 12-19 years) classified as having Lenke type 1 AIS (1A: 15 cases, 1B: 8 cases, 1C: 4 cases) were analyzed. The mean Cobb angle of the main curve was 55.9 ±â€¯14.4°. Axial CT myelography images were selected from the T4 to T12 vertebrae, and 243 images were analyzed. Outer cortical pedicle width, inner cortical pedicle width, pedicle length, chord length, transverse pedicle angle, the angle of rotation (RAsag) of the vertebra, and the distance between the spinal cord and concave (Dc) and convex pedicles (Dv) were calculated from landmark locations. RESULTS: The mean concave outer cortical pedicle width was larger than the mean convex outer cortical pedicle width at T4, T5, T11, and T12 (p < 0.05) and smaller than the mean convex outer cortical pedicle width around the apex of the curve from T7 to T9 (p < 0.05). The mean concave inner cortical pedicle width was larger than the mean convex inner cortical pedicle width at T4, T5, and T11 (p < 0.05) and smaller than the mean convex inner cortical pedicle width around the apex of the curve at T7 and T8 (p < 0.001). The mean Dc was smaller than the mean Dv around the apex of the curve from T6 to T11 (p < 0.05). Dv was significantly correlated with the convex outer cortical pedicle width (R = 0.286, p < 0.001), convex inner cortical pedicle width (R = 0.202, p = 0.002), convex transverse pedicle angle (R=-0.286, p < 0.001), and RAsag (R = 0.277, p < 0.001). Dc was significantly correlated with the concave outer (R = 0.269, p < 0.001) and inner cortical pedicle width (R = 0.230, p < 0.001). CONCLUSION: The distance from the spinal cord to the medial wall of the pedicle was significantly correlated with outer and inner cortical pedicle width, and the potential risk of spinal cord injury by pedicle screw is increased with insertion into a narrower pedicle, especially on the concave side around the apex.

Magnetic resonance imaging evaluation of intervertebral disc injuries can predict kyphotic deformity after posterior fixation of unstable thoracolumbar spine injuries.

The aim of the present study is to identify factors correlated with kyphotic deformity after thoracolumbar spine injuries. We performed a retrospective case-control study with data from thoracolumbar spine fracture patients who were treated with posterior spinal fixation. Patients with a follow-up period shorter than 6 months and who experienced low-energy trauma were excluded. Intervertebral disc injuries (IDIs) were graded from 0 to 3 upon admission in accordance with Sander's classification of traumatic intervertebral disc lesions. Vertebral wedge angles (VWAs) and local kyphosis angles (LKAs) were also measured. Patients were allocated to kyphosis and control groups if they had LKA correction losses of ≥10° and <10°, respectively. Forty-eight patients followed over a median period of 25 months were included. The median correction loss at the site of the injured vertebral body was 2.0°. The median LKA correction loss was 9.0°. Twenty-three and 25 patients were allocated to the kyphosis and control groups, respectively. Univariate analysis revealed that the median age was significantly lower in the kyphosis (35 years) than control group (56 years). The level of injury and IDI severity also significantly differed between groups, with a significantly greater proportion of more severe IDI cases in the kyphosis than control group. Finally, significantly more patients in kyphosis group underwent fusion (kyphosis, 19 vs control, 13) and implant removals (kyphosis, 19 vs control, 10). Multiple regression analysis revealed that IDI severity according to Sander's classification (P = .005; odds ratio, 5.263; 95% confidence interval [CI], 1.637-16.927) and implant removal (P = .011; odds ratio, 7.980; 95% CI, 1.603-39.728) were significantly associated with kyphotic deformity. IDI severity at initial magnetic resonance imaging (MRI) evaluation and implant removal are associated with kyphotic deformity after posterior fixation of thoracolumbar spine injuries. Thus, initial MRI evaluation of IDIs could be used to predict of recurrent kyphosis.

Enhancing the effects of exfoliated carbon nanofibers using bone morphogenetic protein in a rat spinal fusion model.

Exfoliated carbon nanofibers (ExCNFs) are expected to serve as excellent scaffolds for promoting and guiding bone-tissue regeneration. We aimed to enhance the effects of ExCNFs using bone morphogenetic proteins (BMPs) and examined their feasibility and safety in clinical applications using a rat spinal fusion model. Group I (n = 15) animals were implanted with the control carrier; Group II (n = 16) animals were implanted with carrier containing 1 µg ExCNFs; Group III (n = 16) animals were implanted with carrier containing 1 µg recombinant human (rh) BMP-2; and Group IV (n = 17) animals were implanted with carrier containing 1 µg rhBMP-2 and 1 µg ExCNFs. The rats were euthanized after 4 or 8 weeks and their spines were explanted and assessed by manual palpation, radiographs, and high-resolution microcomputerized tomography (micro-CT); the spines were also subjected to histological analysis. The fusion rates in Group IV (25.0%: 4-week, 45.5%: 8-week) were considerably higher than in Groups I (0%: 4-week, 0%: 8-week), II (0%: 4-week, 15.0%: 8-week), and III (16.7%: 4-week, 30.0%: 8-week). These results demonstrated the enhancement of ExCNF bone fusion effects by BMP in a rat spinal fusion model. Our results suggest that the enhancement of ExCNFs effects by BMP makes this combination a possible attractive therapy for spinal fusion surgeries. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2892-2900, 2018.

Relationship of T1 slope with loss of lordosis and surgical outcomes after laminoplasty for cervical ossification of the posterior longitudinal ligament.

OBJECTIVE: T1 slope (T1S) has emerged as a predictor of kyphotic alignment change after laminoplasty. Although it was reported that patients with cervical ossification of the posterior longitudinal ligament (OPLL) and higher T1S had more pronounced lordotic curvature before surgery and higher loss of cervical lordosis after surgery, few studies have attempted to correlate these findings with clinical outcomes. We aimed to investigate the relationship of T1S with loss of cervical lordosis and surgical outcomes after laminoplasty for cervical OPLL. PATIENTS AND METHODS: 35 consecutive patients (26 men and 9 women) with cervical OPLL who underwent double-door laminoplasty were followed for more than 12 months. Radiological and clinical measurements were performed to analyze the following parameters: pre and postoperative C2-C7 Cobb lordotic angle (LA), preoperative C2-C7 range of motion (ROM), loss of cervical lordosis, percentage of change in postoperative kyphosis, pre and postoperative C2-C7 sagittal vertical axis (SVA), change in C2-C7 SVA and occupying ratio of the OPLL, Japanese Orthopedic Association (JOA) score recovery rate, preoperative MRI grade. RESULTS: Patients were divided into 2 groups according to preoperative T1 slope, with the cutoff value being the average preoperative T1 slope. Preoperative C2-C7 Cobb LA (P=0.007) and loss of cervical lordosis (P=0.034) differed between the two groups. Preoperative C2-C7 Cobb LA (R=0.50, P=0.002) and loss of cervical lordosis (R=0.36, P=0.036) were significantly correlated to preoperative T1S. Multivariate linear regression analysis showed that the preoperative T1S was not related to JOA score recovery rate and the preoperative MRI grade (OR=-9.985, P=0.015) was only related to JOA score recovery rate. CONCLUSION: Although the degree of alignment compromise is correlated with the preoperative T1S, clinical outcomes demonstrate overall improvement after cervical laminoplasty with cervical OPLL, regardless of preoperative T1S.

Spondylectomy and lateral lumbar interbody fusion for thoracolumbar kyphosis in an adult with achondroplasia: A case report.

RATIONALE: Fixed thoracolumbar kyphosis with spinal stenosis in adult patients with achondroplasia presents a challenging issue. We describe the first case in which spondylectomy and minimally invasive lateral access interbody arthrodesis were used for the treatment of fixed severe thoracolumbar kyphosis and lumbar spinal canal stenosis in an adult with achondroplasia. PATIENT CONCERNS: A 61-year-old man with a history of achondroplastic dwarfism presented with low back pain and radiculopathy and neurogenic claudication. DIAGNOSES: Plain radiographs revealed a high-grade thoracolumbar kyphotic deformity with diffuse degenerative changes in the lumbar spine. The apex was located at L2, the local kyphotic angle from L1 to L3 was 105°, and the anterior area was fused from the L1 to L3 vertebrae. MRI revealed significant canal and lateral recess stenosis secondary to facet hypertrophy. INTERVENTIONS: We planned a front-back correction of the anterior and posterior spinal elements. We first performed anterior release at the fused part from L1 to L3 and XLIF at L3/4 and L4/5. Next, the patient was placed in the prone position. Spondylectomy at the L2 vertebra and posterior fusion from T10 to L5 were performed. Postoperative radiographs revealed L1 to L3 kyphosis of 32°. OUTCOMES: No complications occurred during or after surgery. Postoperatively, the patient's low back pain and neurological claudication were resolved. No worsening of kyphosis was observed 24 months postoperatively. LESSONS: Circumferential decompression of the spinal cord at the apical vertebral level and decompression of lumbar canal stenosis were necessary. Front-back correction of the anterior and posterior spinal elements via spondylectomy and lateral lumbar interbody fusion is a reasonable surgical option for thoracolumbar kyphosis and developmental canal stenosis in patients with achondroplasia.

Surgical outcomes after laminoplasty for cervical spondylotic myelopathy: A focus on the dynamic factors and signal intensity changes in the intramedullary spinal cord on MRI.

OBJECTIVE: We aimed to analyze the relationship between the dynamic factors and signal intensity changes in the intramedullary spinal cord on MRI, and surgical outcomes, following double-door laminoplasty for cervical spondylotic myelopathy (CSM). PATIENTS AND METHODS: This retrospective study included 100 consecutive patients who underwent double-door laminoplasty for CSM. The following factors were analyzed: JOA score recovery rate, age, duration from onset to surgery, intraoperative bleeding, signal intensity changes in the intramedullary spinal cord on MRI, pre and postoperative C2-7 lordotic angle (LA), changes in C2-7 LA, pre and postoperative C2-7 range of motion (ROM), and pre and postoperative segmental ROM. The Charlson Comorbidity Index (CCI) was also used for the assessment of complications. RESULTS: Age, CCI, preoperative segmental ROM, and pre and postoperative MRI grade significantly correlated with JOA score recovery rate (P<0.01), whereas number of expanded laminae, duration from onset to surgery, surgery time, intraoperative bleeding, preoperative and postoperative C2-7 LA, change in C2-7 LA, and preoperative C2-7 ROM did not. Multivariate analysis showed that the preoperative segmental ROM (OR=-0.988, P=0.017) and preoperative MRI grade (OR=-7.170, P=0.042) were significantly associated with JOA score recovery rate. CONCLUSION: Considering the dynamic factors, there was no correlation with C2-7 ROM and surgical outcome, but preoperative segmental ROM and a change in signal intensity of the intramedullary spinal cord on MRI were negatively correlated with surgical outcome. From these results, we suggest that preoperative segmental ROM is possibly associated with spinal cord damage due to repeated minor trauma and affects surgical outcome of laminoplasty.