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Background: Although severe cervical compressive-extension (CE) injuries are usually repaired using a combined anterior-posterior approach, the repair is possible using a posterior approach alone with reliable anchors. This study aimed to present the outcomes and imaging analysis results of posterior cervical decompression and fusion (PCDF) for severe CE injuries., Methods: We retrospectively reviewed 16 patients who underwent PCDF surgery for severe CE injuries (>50% subluxation) between January 2012 and December 2018. All patients completed 1-year follow-up, and their mean age at the time of surgery was 63.5 years. American Spinal Injury Association Impairment Scale (AIS) grade, kyphotic angle of lower vertebra (KALV), and anterior defect area of lower vertebra (ADLV) were assessed preoperatively., Results: Of 16 patients, nine patients improved at the final follow-up, and eight patients could walk with or without assistance. All patients achieved bone union postoperatively, but four patients showed progression of correction loss of ≥10°. Therefore, patients were divided into two groups: NL group with correction loss of <10°; L group with correction loss of ≥10°. All patients in L group showed KALV of ≥15°, while 10 of 12 patients in NL group showed KALV of <15°. Furthermore, all patients in L group showed ADLV of ≥50%, whereas all patients in NL group showed ADLV of <50%., Conclusions: PCDF is feasible and a favorable procedure for severe CE injuries that require early reduction and cervical spinal stabilization. However, in the cases of advanced destruction of the anterior vertebra, loss of correction after PCDF might occur postoperatively., Competing Interests: Declaration of competing interest We have no conflict of interest in this study., (Copyright © 2022 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Objective: Although the number of elderly patients requiring lumbar fusion for lumbar degenerative disorders has increased over time, the postoperative outcomes of lumbar fusion in very elderly patients (> 85 years) remains unknown. This study aimed to evaluate the comprehensive outcomes of lumbar fusion in elderly patients older than 85 years with mid-term follow-up., Methods: The authors retrospectively researched patients older than 85 years who underwent single- or double-level posterior lumbar interbody fusion or transforaminal lumbar interbody fusion from 2012 to 2019. Twenty-nine patients who had at least 2 years of follow-up were included in this study. The average age was 86.4 years, and the average follow-up period was 42.2 months. Each patient was matched with 60- to 75-year-old controls. The Oswestry Disability Index (ODI) score; Roland-Morris Disability Questionnaire (RMDQ) score; Japanese Orthopaedic Association (JOA) score; JOA recovery rate; and low-back pain (LBP), leg pain, and leg numbness visual analog scale (VAS) scores were obtained. The spinopelvic parameters were measured using lateral standing radiographs of the whole spine., Results: Although there were no significant differences in the ODI, RMDQ, JOA recovery rate, and leg pain and leg numbness VAS scores at 2 years postoperatively between the very elderly and control groups, the VAS LBP score was significantly lower in the very elderly group than in the control group. Preoperative and postoperative sagittal vertical axes were significantly higher and sacral slopes were significantly lower in the very elderly group than in the control group. The incidences of postoperative delirium and new lumbar vertebral fracture were significantly higher in the very elderly group (17.2%) than in the control group (4.6%)., Conclusions: This study showed that lumbar fusion could be performed in patients older than 85 years with satisfactory postoperative outcomes at the 2-year follow-up. In contrast, progressive spinopelvic sagittal imbalance, the incidence of lumbar vertebral fracture up to the final follow-up, and postoperative delirium were greater in the very elderly group than in the control group.

Study Design: Retrospective investigation using a prospectively collected database., Objective: To examine the appearance and characteristics of vertebral bone marrow edema (BME) in the normal healing of lumbar interbody fusion., Summary of Background Data: Although BME in pathological spinal conditions has been well-documented, the patterns and characteristics of BME in the normal healing process of spinal fusion remains unexplored., Materials and Methods: We reviewed imaging from 225 patients with normal healing following posterior lumbar interbody fusion or transforaminal lumbar interbody fusion. BME was identified on magnetic resonance imaging at the third postoperative week and categorized with respect to its appearance, including assessment of area and extension within the relevant vertebrae., Results: Three hundred eighty-nine of the 450 instrumented vertebrae (86.4%) displayed evidence BME. All instances of BME were associated with the area of contact with the endplate. The average extent of BME was 32.7±1.0%. BME within normal healing following interbody fusion could be categorized into four types: no edema (13.6%), anterior corner (36.6%), around-the-cage focal (48.0%), and diffuse (1.8%). Anterior corner BME was significantly associated with instances of single cage placement than in dual cages (42.6% vs. 24.7%, P =0.0002). Single cages had a significantly higher rate of BME than dual cages (92.0% vs. 75.3%, P <0.0001). The extent of BME was significantly greater in the single cage cohort (36.9% vs. 24.2% in dual cages, P <0.0001)., Conclusions: This serves as the first study demonstrating the patterns of BME associated with normal healing following lumbar interbody fusion procedures. Anterior corner BME and around-the-cage focal BME were the most common patterns encountered, with diffuse BME a relatively rare pattern. These findings might contribute to the better differentiation of postoperative pathological events from normal healing following lumbar interbody fusion., Level of Evidence: 4., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Background: There have been no prior reports of real-time detailed records leading to complete quadriplegia immediately after fracture dislocation in high-energy trauma. Here, we report a case of cervical dislocation in which the deterioration to complete motor paralysis (modified Frankel B1) and complete recovery (Frankel E) could be monitored in real time after reduction in the hyperacute phase., Case Presentation: A 65-year-old man was involved in a car accident and sustained a dislocation at the C5/6 level (Allen-Ferguson classification: distractive flexion injury stage IV). His paralysis gradually deteriorated from Frankel D to C 2 hours after the injury and from Frankl C to B 5 hours after the injury. His final neurological status immediately before reduction was Frankel B1 (complete motor paralysis with sensation only in the perianal region). Reduction was completed within 6 h and 5 min after injury, and spinal fusion was subsequently performed. The patient exhibited rapid motor recovery immediately after surgery, and was able to walk independently on postoperative day 14., Conclusions: This case suggests that there is a mixture of cases in which the spinal cord has not been catastrophically damaged, even if the patient has complete motor paralysis. Prompt reduction has the potential to improve neurological function in such cases., (© 2022. The Author(s).)

Background: The aim of this study was to intraoperatively assess the effects of multilevel facetectomy on segmental spinal flexibility in patients with thoracic adolescent idiopathic scoliosis., Methods: Twenty patients who underwent posterior thoracic adolescent idiopathic scoliosis curve correction were evaluated. Compressive or distractive loaded force of 50N was applied on the handle of a compressor or distractor connected to the necks of pedicle screws inserted at T7 to T11. Segmental spinal flexibility rates were calculated based on the distance between screw heads under the loaded and unloaded conditions. In addition, the flexibility rates were obtained before and after multilevel facetectomy., Findings: Absolute flexibility rates of all segments significantly increased after multilevel facetectomy under both compressive and distractive forces (P < 0.01). The absolute change in the flexibility rate was significantly higher at the concave side than at the convex side under both compressive (P < 0.01) and distractive loaded forces (P = 0.046). No significant correlation was found between change in the flexibility rates and preoperative Cobb angle or preoperative curve flexibility., Interpretation: From a biomechanical point of view, multilevel facetectomy provides proper spinal flexibility to improve the correction rate of posterior adolescent idiopathic scoliosis surgery. The effects are higher at the concave side than at the convex side., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Background: Adolescent idiopathic scoliosis (AIS) patients typically undergo surgical treatment as teenagers, follow-ups of >5 years are necessary to evaluate effects on peak pulmonary reserves. However, limited data is available regarding the long-term (>10 years) effects of surgical intervention on pulmonary function (PF) in patients with thoracic AIS., Objective: To provide long-term (>10 years) information on the PF after posterior spinal fusion for treating main thoracic AIS. We especially investigated whether surgical correction for AIS led to impairment of the PF., Methods: A total of 35 patients with main thoracic AIS treated with posterior spinal fusion were included. Radiographs and PF tests, which included measurements of absolute and percent-predicted values of forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1), were evaluated., Results: Mean age at surgery was 14.9 years (12-19 years). Mean follow-up period was 15.1 years (10-24 years). Although the final postoperative FVC and FEV1 absolute values were higher than the preoperative values, the differences were not statistically significant (p = 0.22 and p = 0.08, respectively). Percent-predicted FVC and FEV1 values between preoperative and final postoperative measurements were not statistically different (p = 0.63 and p = 0.29, respectively). However, for the patients who presented with pulmonary impairment preoperatively, both the FVC and FEV1 significantly increased at the final follow-up (p = 0.01 and p = 0.01, respectively)., Conclusions: Long-term results of AIS patients who underwent posterior spinal fusion in main thoracic curves demonstrated absolute and percent-predicted PF test values similar to preoperative measurements; thus, indicating that posterior spinal fusion did not decrease PF 15 years after the initial surgery. Instead, patients with severe preoperative pulmonary impairment might show some degree of improvement after surgery., Competing Interests: The authors have declared that no competing interests exist.

Study Design: Experimental study of spinal rod as per the American Society for Testing Materials (ASTM) F2193 methodology for static and dynamic four-point bending., Objective: The hypotheses underlying this study were that the notch-free, curved rod would have a significantly higher ultimate load and fatigue strength compared with conventional notched curved rods. This study aimed to analyze the mechanical properties of notch-free curved rods compared with conventional notched rods., Summary of Background Data: The goal of instrumented spinal fusion in the management of spinal deformities is to realign the spine and maintain the correction and stability in order to obtain arthrodesis. Although rod curvature could play an important role, intraoperative contouring of the straight rod induces notches into the rod, leading to decreased fatigue strength., Methods: Commercially produced titanium alloy (ϕ6.0 mm) and cobalt chromium alloy (ϕ5.5 mm) spinal rods were assessed by four-point bending tests in accordance with the ASTM F2193., Results: Static four-point bending tests for the curved spinal rods showed that cobalt chromium alloy rods had significantly higher stiffness compared with titanium alloy rods. Notch-free cobalt chromium alloy rods had a significantly higher ultimate load than the conventional notched cobalt chromium alloy and titanium alloy rods. The dynamic four-point bending test showed that force/displacement at a minimum force at 2,500,000 cycles was larger in the notch-free cobalt chromium alloy rod than in the notched cobalt chromium alloy rod., Conclusion: The notch-free curved cobalt chromium alloy rod is likely to maintain its curvature after spinal deformity surgery with a decreased risk of breakage and could overcome the problems of the conventional notched rod such as breakage and spring-back., Level of Evidence: N/A.

Background: This study aimed to identify the incidence and causes of a second rise in C-reactive protein (CRP) levels following spinal instrumentation surgery and to help determine how an abnormal CRP response should be interpreted and managed during postoperative care., Methods: The medical records of 948 patients who underwent instrumented spine fusion surgery and met the inclusion criteria were retrospectively reviewed to assess the frequency and causes of a second rise (SR) of CRP. A SR of CRP was defined when the CRP level after postoperative day 7 increased by more than 0.5 mg/dl from that at the previous time-point. The diagnostic cut-off value of CRP elevation for detection of surgical site infection (SSI) was determined. Cut-off values were analyzed using receiver operating characteristic (ROC) curves. Bayes' theorem was used to determine blood test posterior probabilities for SSI-positive cases using cutoff values of re-evaluated CRP levels., Results: SR of CRP occurred in 107 of the 948 patients. Of the patients with SR of CRP, 38 (35%) patients had developed SSI, 33 (31%) patients had causes other than SSI, and the remaining 36 patients had unidentified causes. Among the patients with SR, excluding those with causes other than SSI, the best diagnostic cut-off value of SR for detection of SSI was 3.04 mg/dl (area under the curve was 0.74). The posterior test probability was 84.4%., Conclusions: For patients with SR of CRP, who had no causes other than SSI, an SR value of 3.04 mg/dl correlated with a high probability of developing SSI., (Copyright © 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.)

Objective: The mechanical alteration in the adolescent/pediatric cervical spine after spinal fusion remains unknown. The purpose of this study was to investigate morphologic changes in the cervical spine in adolescent/pediatric patients who underwent spinal fusion., Methods: Ten adolescent/pediatric patients (9-18 years) who underwent cervical spinal fusion were included. The anteroposterior diameter (AP-D) of the vertebral body was evaluated using lateral radiographs. The AP-D ratio was defined as the ratio of the AP-D at final follow-up to the postoperative value. The kyphosis angles at the fused level and cervical spine (C2-C7) also were measured., Results: The mean follow-up period was 20.0 years (range, 12-40 years). The AP-D was reduced in 4 patients and increased or remained unchanged in 6 patients. The AP-D reduction was usually seen at the middle of the fused levels and was remarkable in patients who underwent kyphosis correction using posterior instrumentation combined with anterior fusion. The AP-D ratio was significantly correlated to segments of anterior fusion (P = 0.029) and the kyphosis angle of the fused levels (P = 0.016)., Conclusions: Cervical kyphosis correction using posterior instrumentation combined with endplate destruction by anterior bone grafting is a risk factor for atrophic morphologic changes in the vertebral body in adolescent/pediatric patients. Endplate destruction and instrumentation-induced stress shielding could alter bone remodeling., (Copyright © 2018 Elsevier Inc. All rights reserved.)

OBJECTIVEThe aim of this retrospective study was to analyze the influence of upper instrumented vertebra (UIV) translation from the C7 plumb line (C7PL) on the long-term postoperative results of patients with main thoracic (MT) adolescent idiopathic scoliosis (AIS).METHODSTwenty-five patients had been treated surgically for AIS with a Lenke type 1 curve and had been followed up for a mean period of 18.2 years. Radiographic parameters, pulmonary function measurements, and clinical outcomes were compared between the patients (n = 15) with UIV translation < 20 mm and those (n = 10) with UIV translation ≥ 20 mm at the final follow-up. Correlations between UIV translation and radiographic or pulmonary function parameters were analyzed.RESULTSPatients with ≥ 20 mm UIV translation at the final follow-up had a significantly larger preoperative UIV translation than that in the patients with < 20 mm UIV translation at follow-up. The former group also had a significantly lower correction rate of the MT curve, higher chest cage ratio, and lower radiographic shoulder height (p = 0.01, 0.005, and 0.025, respectively) at the final follow-up. The Scoliosis Research Society (SRS)-30 Questionnaire scores were equivalent between the two groups. Correlation analysis showed that the following parameters were significantly associated with UIV translation: MT curve correction rate (r = -0.481, p = 0.015), chest cage ratio (r = 0.673, p < 0.001), and percent-predicted forced expiratory volume in 1 second (r = -0.455, p = 0.033).CONCLUSIONSThe UIV translation should be considered an important factor that influences postoperative results. In MT AIS patients whose preoperative upper end vertebra (UEV) is distant from the C7PL, the UIV should be selected above the UEV to prevent large UIV translation at the postoperative follow-up.

Adolescent idiopathic scoliosis (AIS), the most common pediatric musculoskeletal disorder, causes a three-dimensional deformity of the spine. Although rod curvature could play an important role in anatomical spinal reconstruction in patients with thoracic AIS, intraoperative contouring of the straight rod induces notches into the rod, leading to decreased fatigue strength. Here, we analyzed pre-bent rod geometries from 46 intraoperative tracings of the rod geometry, which can provide anatomical spinal reconstruction in patients with thoracic AIS. The center point clouds of the rod shapes were extracted and approximated as arcs and straight lines. The difference between the center point clouds were evaluated using the iterative closest point methods. When the rod shapes were divided into six groups based on length followed by hierarchical cluster analysis, 10 representative rod shapes were obtained with a difference value of 5 mm. Thus, we identified optimized rod shapes to guide anatomical spinal reconstruction for thoracic AIS, which will reduce not only the risk of rod breakage but also operation time, leading to decreased patient burden. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:3219-3224, 2018., (© 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Purpose: The cervical pedicle screw (CPS) requires careful and accurate placement because of the critical risk for neurovascular injury. This study aimed to introduce and evaluate the safety and efficacy of a new CPS placement technique using intraoperative C-arm cone-beam CT (CBCT) and a pilot screw without navigation system., Methods: This was a case-control study to compare the accuracy and safety of intraoperative C-arm CBCT-guided CPS placement with freehand CPS placement under lateral fluoroscopy using control data from a previous multicenter study. A total of 166 CPSs were inserted under intraoperative C-arm CBCT guidance in 48 consecutive patients (20 rheumatoid arthritis, 16 degenerative spinal disorders, 6 spinal tumor, 2 congenital deformity, 2 ossification of posterior longitudinal ligament, and 2 fracture dislocation). Accuracy and safety of CPS placement were assessed., Results: The overall malposition rate was 2.4% (4 screws in grade 1: malposition by less than half-screw diameter, 0 in grade 2: malposition by more than half-screw diameter), which was significantly lower than the reported malposition rate of 14.8% in lateral fluoroscopy-guided freehand placement. There were no complications directly related to CPS insertion. The average estimated effective radiation dose per surgery was 14.7 mSv., Conclusions: The novel technique enables intraoperative adjustment of the trajectory of the CPS as well as confirmation of the CPS path before penetrating the isthmus of the pedicle, resulting in accurate and safe CPS placement, which outweighs the demerits of radiation exposure. These slides can be retrieved under Electronic Supplementary Material.

Study Design: A prospective, nonrandomized study., Objective: The aim of this study was to assess surgical outcomes of multilevel facetectomy and rod curvature with simultaneous double-rod rotation technique for anatomical spinal reconstruction in thoracic adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Although some surgical techniques maintain or restore thoracic kyphosis (TK), next-generation strategies for thoracic AIS should include corrections in three anatomical planes., Methods: The study included 39 consecutive patients with Lenke 1 or Lenke 2 thoracic AIS treated at our institution. After all-level facetectomy at instrumentation level, except for the lowest intervertebral segment, two rods were identically bent to guide postoperative anatomical TK without reference to the intraoperative coronal alignment of the AIS deformity. Outcome measures included patient demographics, radiographic measurements, and Scoliosis Research Society (SRS) questionnaire scores., Results: After 2 years of follow-up, the average main thoracic Cobb angle correction rate was 83.5%, and the final correction loss was 2.2°. The average preoperative TK (T5-T12) significantly increased from 13.2° to 24.6° (P < 0.001) at final follow-up. The percentage of patients with a T6-T8 location of the TK apex significantly increased from 51.3% preoperatively to 87.2% at final follow-up. The average preoperative vertebral rotation angle significantly decreased from 18.7° to 12.8° postoperatively (P < 0.001). The average preoperative total SRS questionnaire score significantly increased from 3.5 to 4.5 (P < 0.001) at final follow-up. There was no implant breakage and vascular and neurologic complications, with all patients demonstrating solid fusion at final follow-up., Conclusion: Multilevel facetectomy and rod curvature play an important role in anatomical spinal reconstruction in patients with thoracic AIS. From the spatiotemporal point of view, four-dimensional correction could be actively performed by rod curvature under multilevel facetectomy and is expected to obtain an anatomical thoracic spine postoperatively, indicating that an anatomically designed rod could be supplied as a pre-bent rod., Level of Evidence: 3.

To highlight the risk of cervical myelopathy due to occult, atraumatic odontoid fracture in patients with rheumatoid arthritis, we retrospectively reviewed radiographic findings and clinical observations for 7 patients with this disorder. This fracture tends to occur in patients with long-lasting rheumatoid arthritis and to be misdiagnosed as simple atlantoaxial dislocation. Since this fracture causes multidirectional instability between C1 and C2 and is expected to have poor healing potential due to bone erosion and inadequate blood supply, posterior spinal arthrodesis surgery is indicated upon identification of the fracture to prevent myelopathy.

Background Context: Controversy exists regarding the effects of multilevel facetectomy and screw density on deformity correction, especially thoracic kyphosis (TK) restoration in adolescent idiopathic scoliosis (AIS) surgery., Purpose: This study aimed to evaluate the effects of multilevel facetectomy and screw density on sagittal plane correction in patients with main thoracic (MT) AIS curve., Study Design: A retrospective correlation and comparative analysis of prospectively collected, consecutive, non-randomized series of patients at a single institution was undertaken., Patient Sample: Sixty-four consecutive patients with Lenke type 1 AIS treated with posterior correction and fusion surgery using simultaneous double-rod rotation technique were included., Outcome Measures: Patient demographics and preoperative and 2-year postoperative radiographic measurements were the outcome measures for this study., Methods: Multiple stepwise linear regression analysis was conducted between change in TK (T5-T12) and the following factors: age at surgery, Risser sign, number of facetectomy level, screw density, preoperative main thoracic curve, flexibility in main thoracic curve, coronal correction rate, preoperative TK, and preoperative lumbar lordosis. Patients were classified into two groups: TK<15° group defined by preoperative TK below the mean degree of TK for the entire cohort (<15°) and the TK≥15° group, defined by preoperative TK above the mean degree of kyphosis (≥15°). Independent sample t tests were used to compare demographic data as well as radiographic outcomes between the two groups. There were no study-specific biases related to conflicts of interest., Results: The average preoperative TK was 14.0°, which improved significantly to 23.1° (p<.0001) at the 2-year final follow-up. Greater change in TK was predicted by a low preoperative TK (p<.0001). The TK <15° group showed significant correlation between change in TK and number of facetectomy level (r=0.492, p=.002). Similarly, significant correlation was found between change in TK and screw density (r=0.333, p=.047). Conversely, in the TK ≥15° group, correlation was found neither between change in TK and number of facetectomy level (r=0.047, p=.812), nor with screw density (r=0.030, p=.880). Furthermore, in patients with preoperative TK<15°, change in TK was significantly correlated with screw density at the concave side (r=0.351, p=.036) but not at the convex side (r=0.144, p=.402)., Conclusions: In patients with hypokyphotic thoracic spine, significant positive correlation was found between change in TK and multilevel facetectomy or screw density at the concave side. This indicates that in patients with AIS who have thoracic hypokyphosis as part of their deformity, the abovementioned factors must be considered in preoperative planning to correct hypokyphosis., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Background Context: Consensus regarding the optimal upper vertebra to be instrumented during surgical treatment of Lenke 5C thoracolumbar and lumbar adolescent idiopathic scoliosis (AIS) remains limited., Purpose: This study aimed to assess whether a short fusion strategy is appropriate for correction of a Lenke 5C AIS curve by anterior correction and fusion surgery using dual-rod instrumentation., Study Design: This study design used retrospective comparative analysis of a prospectively collected, consecutive, non-randomized series of patients at a single institution., Patient Sample: Thirty consecutive patients with Lenke 5C AIS treated with anterior correction and fusion surgery using dual-rod instrumentation were included., Outcome Measures: Patient demographics, radiographic measurements, and Scoliosis Research Society-22 questionnaire (SRS-22) scores were the outcome measures for this study., Methods: Thirty patients were treated surgically for AIS with a Lenke 5C curve (mean age, 14.4 years [11-19 years)]) and followed up for a mean period of 17.2 years (12-23 years). Radiographical parameters and clinical outcomes were compared between patients treatment with the end vertebra (EV) instrumented (n=14) and those treated by short fusion (S group) with instrumentation starting at the vertebra one level caudal to the EV (n=16 patients). There were no study-specific biases related to conflicts of interest., Results: In the EV group, a mean preoperative Cobb angle of 56° was corrected to 5° after surgery and to 8° at the final follow-up. In the S group, a mean preoperative Cobb angle of 55° was corrected to 10° after surgery and 14° at the final follow-up. The mean correction rate at the final follow-up was significantly lower in the S group (74%) than in the EV group (86%; p=.020). The coronal and sagittal balance, thoracic kyphosis, lumbar lordosis, and clinical outcomes evaluated using SRS-22 did not differ between the two groups., Conclusions: The short fusion strategy, which involves instrumentation of the vertebra one level caudal to the upper EV, can be considered as an alternative to the conventional strategy, which includes instrumentation of the upper EV, for treating Lenke 5C curves via anterior spinal fusion., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Purpose: There is limited consensus on the optimal surgical strategy for double thoracic adolescent idiopathic scoliosis (AIS). Recent studies have reported that pedicle screw constructs to maximize scoliosis correction cause further thoracic spine lordosis. The objective of this study was to apply a new surgical technique for double thoracic AIS with rigid proximal thoracic (PT) curves and assess its clinical outcomes., Methods: Twenty one consecutive patients with Lenke 2 AIS and a rigid PT curve (Cobb angle ≥30º on side-bending radiographs, flexibility ≤30 %) treated with the simultaneous double-rod rotation technique (SDRRT) were included. In this technique, a temporary rod is placed at the concave side of the PT curve. Then, distraction force is applied to correct the PT curve, which reforms a sigmoid double thoracic curve into an approximate single thoracic curve. As a result, the PT curve is typically converted from an apex left to an apex right curve before applying the correction rod for PT and main thoracic curve., Results: All patients were followed for at least 2 years (average 2.7 years). The average main thoracic and PT Cobb angle correction rate at the final follow-up was 74.7 and 58.0 %, respectively. The average preoperative T5-T12 thoracic kyphosis was 9.3°, which improved significantly to 19.0° (p < 0.0001) at the final follow-up. Although 71 % patients had preoperative level shoulders or a positive radiographic shoulder height, all patients had mildly imbalanced or balanced shoulders at the final follow-up. The average preoperative main thoracic apical vertebral rotation angle of 20.7° improved significantly after surgery to 16.4° (p = 0.0046), while the average preoperative total SRS questionnaire score of 3.7 improved significantly to 4.4 (p = 0.0012) at the final follow-up., Conclusions: Radiographic findings and patient outcomes were satisfactory. Thoracic kyphosis can be maintained or improved, while coronal and axial deformities can be corrected using SDRRT for Lenke 2 AIS with a rigid PT curve.

Purpose: To evaluate the osteoconductivity and the bonding strength of the newly developed interbody cage covered with the porous titanium sheet (porous Ti cage) to vertebral bodies in a sheep model., Methods: Twelve sheep underwent anterior lumbar interbody fusion at L2-3 and L4-5 using either the new porous Ti cages (Group-P) or conventional Ti cages with autogenous iliac bone (Group-C). The animals were euthanized at 2 or 4 months postoperatively and subjected to radiological, biomechanical, and histological examinations., Results: Computed tomography analyses showed that the ratio of bone contact area in Group-P was significantly increased at 4 months compared with that at 2 months (p = 0.01). Although the ratio of bone contact area in Group-C was significantly higher than Group-P at 2 months (p < 0.001), there was no statistically significant difference between the two groups at 4 months. Biomechanical test showed that there was no significant difference in bonding strength between the two groups at either 2 or 4 months. Histological analyses revealed that the bone apposition ratio increased significantly with time in Group-P (p < 0.001). Although Group-C showed significantly higher bone apposition ratio than Group-P at 2 months (p = 0.001), there was no statistical difference between the two groups at 4 months., Conclusions: There was bone ingrowth into the porous Ti sheet, and bonding capacity of the porous Ti cage to the host bone increased with time. However, the speed of union to the bone with a porous Ti cage was marginally lower than a conventional cage along with an autogenous bone graft. Although it needs further experiment with a larger sample size, the results of the current study suggested that this material could achieve interbody fusion without the need for bone grafts.

Study Design: Retrospective analysis of a prospectively collected, consecutive, nonrandomized series of patients., Objective: To assess the surgical outcomes of the simultaneous double-rod rotation technique for treating Lenke 1 thoracic adolescent idiopathic scoliosis (AIS)., Summary of Background Data: With the increasing popularity of segmental pedicle screw spinal reconstruction for treating AIS, concerns regarding the limited ability to correct hypokyphosis have also increased., Methods: A consecutive series of 32 patients with Lenke 1 main thoracic AIS treated with the simultaneous double-rod rotation technique at our institution was included. Outcome measures included patient demographics, radiographical measurements, and Scoliosis Research Society questionnaire scores., Results: All 32 patients were followed up for a minimum of 2 years (average, 3.6 yr). The average main thoracic Cobb angle correction rate and the correction loss at the final follow-up were 67.8% and 3.3°, respectively. The average preoperative thoracic kyphosis (T5-T12) was 11.9°, which improved significantly to 20.5° (P < 0.0001) at the final follow-up. An increase in thoracic kyphosis was significantly correlated with an increase in lumbar lordosis at the final follow-up (r = 0.42). The average preoperative vertebral rotation angle was 19.7°, which improved significantly after surgery to 14.9° (P = 0.0001). There was no correlation between change in thoracic kyphosis and change in apical vertebral rotation (r =-0.123). The average preoperative total Scoliosis Research Society questionnaire score was 3.0, which significantly improved to 4.4 (P < 0.0001) at the final follow-up. Throughout surgery and even after, there were no instrumentation failures, pseudarthrosis, infection of the surgical site, or clinically relevant neurovascular complications., Conclusion: The simultaneous double-rod rotation technique for treating Lenke 1 AIS provides significant sagittal correction of the main thoracic curve while maintaining sagittal profiles and correcting coronal and axial deformities., Level of Evidence: 4.

Background Context: With the increase of the elderly population, osteoporotic vertebral fractures have been frequently reported. Surgical intervention is usually recommended in osteoporotic vertebral collapse with neurologic deficits. However, very few reports on surgical interventions exist., Purpose: To compare surgical results of anterior and posterior procedures for treating osteoporotic thoracolumbar vertebral collapse with sustained neurologic deficits., Study Design: Retrospective comparative study., Patient Sample: Fifty patients who sustained osteoporotic thoracolumbar vertebral collapse with neurologic deficits were treated either by anterior decompression and strut graft (n=32) or by posterior decompression and pedicle screw fixation with vertebroplasty (n=18)., Outcome Measures: Incidence of complications, sagittal Cobb angle, spinal canal encroachment, and Japanese Orthopedic Association score., Methods: The authors retrospectively reviewed the results of a consecutive series of patients undergoing anterior decompression and strut graft or posterior decompression and pedicle screw fixation with vertebroplasty for osteoporotic thoracolumbar vertebral collapse with neurologic deficits. Operative notes, clinical charts, and radiographs were analyzed., Results: Operative time was similar between the groups, but intraoperative blood loss was significantly lower in the posterior group. All patients showed neurologic recovery. No significant difference was observed in the neurologic improvement, kyphosis correction angle, and loss of correction. Perioperative respiratory complications were found in 11 patients (34%) in the anterior group. In the anterior group, early posterior reinforcement was required in patients with very low bone density below 0.60 g/cm(2) and/or in those with three segments of instrumentation for two vertebral collapses. Posterior group patients did not undergo additional surgery., Conclusions: Anterior reconstruction for osteoporotic vertebral collapse is significant because anterior elements, particularly those at the thoracolumbar junction, play a major role in load bearing. However, difficulties arise when anterior reconstruction is performed in cases with very low bone density and in those with multiple vertebral collapse., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Objective: To evaluate the preoperative and perioperative predictors of persistent leg numbness following lumbar fusion in patients aged ≥ 75 years. Methods: This single-center retrospective study examined 304 patients aged ≥ 75 years who underwent lumbar fusion for lumbar degenerative disease (102 men, 202 women; mean age, 79.2 [75–90] years). The visual analogue scale (VAS) score for leg numbness was examined preoperatively and at 2 years postoperatively. The persistent leg numbness group included patients with a 2-year postoperative VAS score for leg numbness ≥ 5 points. The demographic data were also reviewed. A multivariate stepwise logistic regression analysis was performed for variables with univariate analysis values of p < 0.2 on univariate analysis. Results: In total, 71 patients (23.4%) experienced persistent postoperative leg numbness. Multivariate logistic regression analysis revealed that a history of lumbar decompression, longer symptom duration, and a preoperative VAS score for leg numbness ≥ 5 points were associated with greater postoperative persistent leg numbness following lumbar fusion. In contrast, other factors, such as sex, body mass index, vertebral fracture, diabetes mellitus, depression, symptom duration, dural injury, operative time, and estimated blood loss, were not. Conclusion: A history of preoperative lumbar decompression, longer symptom duration, and greater preoperative VAS scores for leg numbness were preoperative predictors of persistent postoperative leg numbness following lumbar fusion in older patients. Although lumbar fusion is expected to improve leg numbness, surgeons should consider the surgical history, duration, and preoperative numbness intensity and explain the potential postoperative persistent leg numbness in advance. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the lowest instrumented vertebra translation (LIV-T) in the surgical treatment of thoracolumbar/lumbar adolescent idiopathic scoliosis and to analyze the radiographic parameters in relation to LIV-T and L4 tilt and global coronal balance. A total of 62 patients underwent posterior spinal fusion (PSF, n = 32) or anterior spinal fusion (ASF, n = 30) and were followed up for a minimum of 2 years. The mean preoperative LIV-T was significantly larger in the ASF group than the PSF (p < 0.01), while the final LIV-T was equivalent. LIV-T at the final follow-up was significantly correlated with L4 tilt and the global coronal balance (r = 0.69, p < 0.01, r = 0.38, p < 0.01, respectively). Receiver-operating characteristic analysis for good outcomes, with L4 tilt <8° and coronal balance <15 mm at the final follow-up, calculated the cutoff value of the final LIV-T as 12 mm. The cutoff value of preoperative LIV-T that would result in the LIV-T of ≤12 mm at the final follow-up was 32 mm in PSF, although no significant cutoff value was calculated in ASF. ASF can centralize the LIV better than PSF with a shorter segment fusion, and could be useful in obtaining a good curve correction and global balance without fixation to L4 in cases with large preoperative LIV-T. [ABSTRACT FROM AUTHOR]

Study Design: Prospective longitudinal study.Objective: The aim of this study was to evaluate temporal changes of bone turnover markers (BTMs) after lumbar spinal fusion in patients without osteoporosis.Summary Of Background Data: Radiological studies are the standard method to monitor bony fusion, but they do not allow a timely assessment of bone healing. BTMs react rapidly to changes in bone metabolism during fusion process and could be an additional tool to monitor this process.Methods: A total of 78 nonosteoporosis patients who had undergone one- or two-level transforaminal lumbar interbody fusion were included. Fusion status was assessed using computed tomography sagittal and coronal images. Serum levels of bone-specific alkaline phosphatase (BAP), procollagen type 1 amino-terminal propeptide (P1NP), and osteocalcin (OC) were measured to assess bone formation, and tartrate-resistant acid phosphatase 5b (TRACP-5b) was measured to assess bone resorption. Serum samples were obtained before surgery and at 1, 2, 4, 8, 13, 26, 39, and 52 weeks after surgery.Results: A solid fusion was achieved in 71 of 78 patients (91%), and seven patients resulted in pseudarthrosis. In the fusion group, the level of all BTMs once decreased at 1 postoperative week. Then, BAP and P1NP reached a peak at 4 weeks after surgery, and TRACP-5b and OC peaked at 8 weeks. Thereafter, the level of P1NP and TRACP-5b gradually got closer to the baseline over a year, and BAP kept high until 52 postoperative weeks. In the pseudarthrosis group, peak level of BTMs was significantly higher and the increased level of BAP and P1NP was kept until 52 weeks.Conclusion: The present study demonstrated dynamics of BTMs after lumbar spinal fusion in patients without osteoporosis. These normal population data contribute as a baseline to evaluate the effect of osteogenic agents on bone metabolism after spinal fusion.Level of Evidence: 2. [ABSTRACT FROM AUTHOR]

Study Design: Experimental study of spinal rod as per the American Society for Testing Materials (ASTM) F2193 methodology for static and dynamic four-point bending.Objective: The hypotheses underlying this study were that the notch-free, curved rod would have a significantly higher ultimate load and fatigue strength compared with conventional notched curved rods. This study aimed to analyze the mechanical properties of notch-free curved rods compared with conventional notched rods.Summary Of Background Data: The goal of instrumented spinal fusion in the management of spinal deformities is to realign the spine and maintain the correction and stability in order to obtain arthrodesis. Although rod curvature could play an important role, intraoperative contouring of the straight rod induces notches into the rod, leading to decreased fatigue strength.Methods: Commercially produced titanium alloy (ϕ6.0 mm) and cobalt chromium alloy (ϕ5.5 mm) spinal rods were assessed by four-point bending tests in accordance with the ASTM F2193.Results: Static four-point bending tests for the curved spinal rods showed that cobalt chromium alloy rods had significantly higher stiffness compared with titanium alloy rods. Notch-free cobalt chromium alloy rods had a significantly higher ultimate load than the conventional notched cobalt chromium alloy and titanium alloy rods. The dynamic four-point bending test showed that force/displacement at a minimum force at 2,500,000 cycles was larger in the notch-free cobalt chromium alloy rod than in the notched cobalt chromium alloy rod.Conclusion: The notch-free curved cobalt chromium alloy rod is likely to maintain its curvature after spinal deformity surgery with a decreased risk of breakage and could overcome the problems of the conventional notched rod such as breakage and spring-back.Level Of Evidence: N/A. [ABSTRACT FROM AUTHOR]