Impact of osteosclerosis on cervical pedicle screw insertion using preoperative CT-based navigation.

PURPOSE: Preoperative computed tomography (CT)-based navigation is used for cervical pedicle screw (CPS) insertion to mitigate the risk of spinal cord and vertebral artery injury. In vertebrae with osteosclerosis due to degeneration or other factors, however, probing may not proceed easily, with difficulty creating the CPS insertion hole. This study investigated the impact of osteosclerosis on the accuracy of CPS insertion. METHODS: A total of 138 patients with CPS inserted at the C3-C7 level using preoperative CT navigation were retrospectively analyzed. Pre- and postoperative CT was employed to investigate screw position and Hounsfield unit (HU) values at the lateral mass to evaluate the degree of osteosclerosis in the CPS insertion pathway. RESULTS: Among 561 CPS insertions, the Grade 3 perforation rate was 1.8%, and the Grade 2 or higher perforation rate was 8.0%. When comparing insertions with and without CPS perforation, HU values were significantly higher in the perforation group (578 ± 191 vs. 318 ± 191, p < 0.01). The frequency of CPS insertion into the mid-cervical spine was also significantly greater in the perforation group (68.9% vs. 62.5%, p < 0.01). Logistic regression analysis revealed that a high HU value at the lateral mass (odds ratio 1.09, 95% confidence interval: 1.07-1.11, p < 0.01) was a significant independent factor associated with CPS deviation. CONCLUSIONS: The screw perforation rate of Grade 2 or higher in CPS insertion using preoperative CT-based navigation was 8.0%. Since osteosclerosis was an independent factor related to CPS deviation, additional care may be required during insertion into affected vertebrae.

Reduction in CT scan number with the reference frame middle attachment method in intraoperative CT navigation for adolescent idiopathic scoliosis.

PURPOSE: Elucidate whether it is preferable to use the reference frame (RF) middle attachment (RFMA) method over the edge of the planned pedicle screw (PS) insertion area for RF placement in the surgery for adolescent idiopathic scoliosis (AIS) with intraoperative computed tomography (CT) navigation. METHODS: Eighty-six consecutive patients (76 female and 10 male; mean age: 15.9 years) with AIS who underwent posterior spinal fusion using intraoperative CT navigation were enrolled. The group with the RF placed at the most distal part of the CT scan range was defined as the distal group (Group D), with other placements classified into the middle group (Group M). PS perforation rate and surgical outcome were compared between the groups. RESULTS: There was no significant difference in perforation rate between Group M and Group D (3.4% vs. 3.0%, P = 0.754). The mean ± standard deviation number of instrumented vertebrae at the first CT scan was significantly higher in Group M (8.2 ± 1.2 vs. 6.3 ± 1.2, P < 0.001), while mean blood loss was significantly lower (266 ± 185 mL vs. 416 ± 348 mL, P = 0.011). The frequency of needing a second CT scan for PS insertion was significantly lower in Group M (38% vs. 69%, P = 0.04). CONCLUSION: The RFMA method in thoracic scoliosis surgery for AIS with intraoperative CT navigation could significantly decrease the number of CT scans and blood loss while maintaining a comparable PS perforation rate to RF placement at the distal end of the planned PS insertion range.

Real-World Effectiveness of Gelatin-Thrombin Matrix Sealant on Blood Loss in Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Spinal Fusion: An Interrupted Time Series Study.

STUDY DESIGN: Retrospective cohort study with interrupted time series analysis. OBJECTIVE: To examine the clinical effectiveness of gelatin-thrombin matrix sealant (GTMS) on blood loss reduction following adolescent idiopathic scoliosis (AIS) surgery. SUMMARY OF BACKGROUND DATA: The real-world effectiveness of GTMS on blood loss reduction in AIS surgery has not been determined. METHODS: The medical records of patients receiving adolescent idiopathic scoliosis surgery were retrospectively collected during a period prior to GTMS approval at our institution (January 22, 2010, to January 21, 2015) as well as during a post-introduction period (January 22, 2015, to January 22, 2020). The primary outcomes were intra-operative blood loss, drain output over 24 hours, and total blood loss (intra-operative blood loss + drain output over 24 hours). Interrupted time series analysis using a segmented linear regression model was employed to estimate the effect of GTMS on blood loss reduction. RESULTS: A total of 179 AIS patients (mean age [range]: 15.4 [11-30] years; 159 female and 20 male; 63 pre-introduction patients and 116 post-introduction patients) were included. After its introduction, GTMS was used in 40% of cases. Interrupted time series analysis revealed changes of -340 mL (95% confidence interval [CI]: -649 to -31, P=0.03) for intra-operative blood loss, -35 mL (95% CI: -124 to 55, P=0.44) for drain output over 24 hours, and -375 mL (95% CI: -698 to -51, P=0.02) for total blood loss. CONCLUSION: The availability of GTMS was significantly associated with reduced intra-operative and total blood loss in AIS surgery. GTMS use as needed is recommended to control intra-operative bleeding in the setting of AIS surgery. LEVEL OF EVIDENCE: 3.

Reliability and validity of gait dynamic balance assessment in adult spinal deformity patients using a two-point trunk motion measuring device.

BACKGROUND CONTEXT: Adult spinal deformity (ASD) patients often complain of walking discomfort. However, dynamic balance evaluation methods of gait in ASD have not been well established. DESIGN: Case series study. PURPOSE: Characterize the gait of ASD patients using a novel two-point trunk motion measuring device. PATIENT SAMPLE: Sixteen ASD patients scheduled for surgery and 16 healthy control subjects. OUTCOME MEASURES: Trunk swing width and track length of the upper back and sacrum. METHODS: Gait analysis was performed using a two-point trunk motion measuring device on 16 ASD patients and 16 healthy control subjects. Three measurements were taken for each subject, and the coefficient of variation was determined to compare measurement accuracy between the ASD and control groups. Trunk swing width and track length were measured in three dimensions for comparisons between the groups. The relationship among output indices, sagittal spinal alignment parameters, and quality of life (QOL) questionnaire scores was examined as well. RESULTS: No significant difference was found for the precision of the device between the ASD and control groups. Compared with controls, the walking style of ASD patients tended to have larger right-left swing of the trunk (+14.0 cm and +23.3 cm at the sacrum and upper back, respectively), larger horizontal plane movement of the upper body (+36.4 cm), less vertical movement (-5.9 cm and -8.2 cm up-down swing at the sacrum and upper back, respectively), and longer gait cycle (+0.13 sec). Regarding QOL in ASD patients, greater right-left/front-back swing of the trunk, greater movement in the horizontal plane, and longer gait cycle were associated with lower QOL scores. Conversely, greater vertical movement was associated with higher QOL. CONCLUSIONS: ASD patients had unique gait characteristics, the intensity of which were associated with diminished QOL. The two-point trunk motion measuring device may be reliable and useful for the clinical assessment of balance during gait in ASD patients.

Impact of Physical Flexibility Changes on Respiratory Function after Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis Surgery.

Introduction: Corrective scoliosis surgery in patients with adolescent idiopathic scoliosis (AIS) increases thoracic volume but does not improve respiratory function (RF). This study evaluates the effect of physical flexibility (PF) improvement after scoliosis surgery on RF. Methods: This study reviewed the records of 61 consecutive patients with AIS (56 female and 5 male; mean±standard deviation age: 14.8±2.2 years, range: 11-20 years) who had undergone posterior spinal fusion (PSF) of the thoracic curve. PF evaluated as finger-floor distance (FFD) was measured preoperatively and one year after surgery. After dividing the cohort into the PF improvement group and the PF nonimprovement group, RF changes at two years postoperative were statistically compared. Using logistic regression analysis, we evaluated the impact of a PF improvement on % forced vital capacity (%FVC) two years after surgery. Results: The rate of patients with increased FVC, %FVC, and forced expiratory volume 1.0 second two years after surgery was 79%, 51%, and 80%, respectively. The PF improvement group exhibited a significantly higher gain in %FVC versus the PF nonimprovement group (P=0.043). Moreover, PF improvement significantly prevented a %FVC decrease (odds ratio 8.43, 95% confidence interval 1.92-59.70; P<0.001), with an adjusted odds ratio of 11.86 (P<0.001). Conclusions: Patients with diminished PF after PSF for AIS may be less likely to achieve postoperative %FVC improvement. As increased postsurgical %FVC had a positive effect on physical function, treatment strategies that focus on maintaining and increasing PF are desirable from an RF viewpoint.

Frequency and Associated Factors of Postoperative Wound Dehiscence in Posterior Cervical Spine Surgery.

OBJECTIVE: Wound dehiscence after cervical spine surgery is a well-known complication that can be a challenge for spine surgeons to manage, especially in cases of exposed implants. However, few studies have focused primarily on this phenomenon in cervical spine surgery to date. This investigation sought to determine the frequency of wound dehiscence following posterior cervical spine surgery and identify patient-based risk factors. METHODS: The medical data of 405 consecutive patients (290 male and 115 female; mean age: 68.9 years) who underwent posterior cervical spine surgery were retrospectively examined. Logistic regression models were employed to examine the prevalence, characteristics, and risk factors of postoperative wound dehiscence. RESULTS: We observed that 5.2% of cervical spine surgery patients experienced procedural postoperative wound dehiscence. In comparisons of dehiscence and non-dehiscence groups, significant differences were found for posterior instrumented fusion (81.0% vs. 45.3%; P < 0.01), extended T1 fusion (57.1% vs. 12.8%; P < 0.01), occipitocervical fusion (19.0% vs. 6.2%; P = 0.048), fused intervertebral levels (4.0 vs. 1.5; P < 0.01), surgical time (246 minutes vs. 165 minutes; P < 0.01), blood loss volume (228 mL vs. 148 mL; P = 0.023), and dialysis (14.3% vs. 1.8%; P = 0.011). Multivariate analysis identified extended T1 fusion and dialysis to be significantly associated with wound dehiscence with odds ratios of 5.82 and 10.70, respectively. CONCLUSIONS: The observed frequency of postoperative wound dehiscence in cervical spine surgery was 5.2%. As extended T1 fusion and dialysis may increase the risk of dehiscence after surgery, patients who display such risk factors may require additional observation and care.

A challenging case of lumbar vertebral burst fracture with alcohol withdrawal delirium: A case report.

BACKGROUND: Delirium tremens is a symptom of alcohol withdrawal syndrome that occurs 48 to 96 hours after the last drink in 5% of withdrawing patients. METHODS: This report describes the clinical progression of a case of lumbar vertebral burst fracture with alcohol withdrawal delirium that was difficult to manage. RESULTS: A 47-year-old man was rushed to our hospital complaining of lumbar back pain and numbness in both lower extremities resulting from a 6-m fall during civil engineering work. Computed tomography (CT) revealed a L1 burst fracture with a highly protruding bone fragment in the spinal canal. Magnetic resonance imaging disclosed significant compression of the conus and intramedullary signal changes. We immediately performed posterior spinal fusion and vertebroplasty using instrumentation. On the 4th postoperative day, he became severely agitated, as diagnosed as having delirium tremens related to alcohol withdrawal syndrome, and soon began appropriate medication with diazepam. Although his symptoms persisted until 6 days postoperatively, follow-up CT detected no evidence of screw loosening or breakage. CONCLUSION: We encountered a patient with severe delirium tremens developing several days after thoraco-lumbar fusion surgery. Prompt internal fixation successfully treated the spinal injury and prevented neurological damage. It may also be necessary to consider treatment strategies for patients with a background of heavy alcohol consumption in consideration of delirium tremens and other symptoms of alcohol withdrawal.

Postoperative Residual Coronal Decompensation Inhibits Self-image Improvement in Adolescent Patients with Idiopathic Scoliosis.

STUDY DESIGN: Retrospective cohort study. PURPOSE: This study aimed to evaluate the relationship between C7 plumb line (C7PL) decompensation and the Scoliosis Research Society (SRS) 22-item patient questionnaire scores, including those related to self-image, preoperatively and 2 years after surgery. OVERVIEW OF LITERATURE: In the surgical treatment of adolescent idiopathic scoliosis (AIS), inferior trunk balance caused by C7PL decompensation can negatively affect patients' quality of life. However, there are few reports in the literature that describe or clarify how postoperative trunk imbalance affects each SRS-22 domain, including self-image domain scores. METHODS: A total of 120 patients with AIS who underwent posterior spinal fusion from August 2006 to March 2017 at our facility and were followed up for 2 years or more were included. Radiological parameters were measured on whole-spine anteroposterior and lateral radiographs. Revised SRS-22 (SRS-22r) values were also recorded. Coronal trunk imbalance was defined as a deviation of ≥2.0 cm between the C7PL and the central sacral vertical line. Patients with and without coronal trunk imbalance at 2 years after surgery were defined as D (+) (decompensation type) and D (-), respectively. Mean SRS-22r values, including function, pain, self-image, mental health, and subtotal were compared between the D (+) and D (-) groups. Logistic regression analysis was performed to detect the preoperative factors related to D (+) using predictors, including curve type, maximum Cobb angle, and coronal trunk imbalance. RESULTS: At 2 years after surgery, the D (+) group had a significantly lower self-image in the domain of SRS-22r scores compared with the D (-) group. Preoperative coronal trunk imbalance was significantly related to D (+) but not to significant changes in the postoperative SRS-22 score in any of the SRS-22 domains. CONCLUSIONS: Postoperative C7PL deviation lowers the self-image in patients with AIS. Patients with preoperative coronal trunk imbalance were significantly more likely to be D (+).

Cervical myelopathy due to amyloid deposition with accompanying cardiac abnormalities.

BACKGROUND: Amyloidosis is a rare group of diseases in which fibrillar amyloid proteins are deposited in systemic organs to result in functional disorder. However, amyloidosis affecting the cervical spine is very rare. We herein describe a case of systemic amyloidosis including a combination of cervical myelopathy with amyloid deposition and cardiac dysfunction due to cardiac amyloidosis. CASE PRESENTATION: An 86-year-old man with cervical myelopathy accompanied with cardiac dysfunction due to cardiac amyloidosis underwent posterior cervical laminectomy from C3 to C4. We were able to identify the patient's cardiac amyloidosis and significant cardiac dysfunction before surgery and manage his perioperative treatment successfully. Preoperative cervical computed tomography (CT) showed multiple fine calcifications below the lamina, which were later confirmed by pathological analysis as amyloid deposition. CONCLUSIONS: This is a relatively rare report of systemic amyloidosis including a combination of cervical myelopathy with amyloid deposition and cardiac dysfunction from cardiac amyloidosis. CT findings of multiple fine calcifications suggest the possibility of amyloidosis and may warrant further examination of cardiac function.

Comparison of spinous process-splitting laminectomy versus posterolateral fusion for lumbar degenerative spondylolisthesis.

BACKGROUND: Although several studies have recently shown that spinous process-splitting laminectomy (SPSL) maintains lumbar spinal stability by preserving posterior ligament components and paraspinal muscles as compared with conventional laminectomy, evidence is scarce on the treatment outcomes of SPSL limited to lumbar degenerative spondylolisthesis. We herein compare the surgical results and global alignment changes for SPSL versus posterolateral lumbar fusion (PLF) without instrumentation for lumbar degenerative spondylolisthesis. METHODS: A total of 110 patients with Grade 1 lumbar degenerative spondylolisthesis who had undergone SPSL (47 patients) or PLF (63 patients) with minimum 1-year follow-up were retrospectively enrolled from a single institutional database. RESULTS: Mean operating time per intervertebral level and intraoperative blood loss per intervertebral level were comparable between the SPSL group and PLF group. Japanese Orthopaedic Association scores, Oswestry disability index, and visual analog scale scores were significantly and comparably improved at 1 year postoperatively in both groups as compared with preoperative levels. The numbers of vertebrae with slip progression to Grade 2 and slip progression of 5% or more at 1 year postoperatively were similar between the groups. In the SPSL group, mean pelvic tilt (PT) was significantly decreased at 1 year postoperatively. In the PLF group, mean lumbar lordosis (LL) was significantly increased, while mean sagittal vertical axis, PT, and pelvic incidence-LL were significantly decreased at 1 year after surgery. CONCLUSIONS: Compared with PLF without instrumentation, SPSL for Grade 1 lumbar degenerative spondylolisthesis displayed comparable results for slip progression and clinical outcomes at 1 year postoperatively.

Tips and pitfalls to improve accuracy and reduce radiation exposure in intraoperative CT navigation for pediatric scoliosis: a systematic review.

BACKGROUND CONTEXT: An increasing number of medical centers are adopting an intraoperative computed tomography (iCT) navigation system (iCT-Navi) to provide three-dimensional navigation for pediatric scoliosis surgery. While iCT-Navi has been reported to provide higher pedicle screw (PS) insertion accuracy, it may also result in higher radiation exposure to the patient. What innovations and studies have been introduced to reduce radiation exposure and further improve PS insertion? PURPOSE: Evaluate the level of evidence and quality of papers while categorizing the tips and pitfalls regarding pediatric scoliosis surgery using iCT-Navi. Compare iCT-Navi with other methods, including preoperative CT navigation. STUDY DESIGN: Systematic review. PATIENT SAMPLE: Articles on pediatric scoliosis surgery with iCT-Navi published through to June 2022. OUTCOME MEASURES: PS perforation rate and patient intraoperative radiation dose. METHODS: Following PRISMA guidelines, the Cochrane Library, Google Scholar, and PubMed databases were searched for articles satisfying the criteria of iCT-Navi use and pediatric scoliosis surgery. The level of evidence and quality of the articles meeting the criteria were evaluated according to the guidelines of the North American Spine Society and American Academy of Orthopedic Surgeons, respectively. The articles were also categorized by theme and summarized in terms of PS insertion accuracy and intraoperative radiation dose. The origins and characteristics of five major classification methods of PS perforation grade were summarized as well. RESULTS: The literature search identified 811 studies, of which 20 papers were included in this review. Overall, 513 pediatric scoliosis patients (381 idiopathic, 44 neuromuscular, 39 neurofibromatosis type 1, 28 congenital, 14 syndromic, seven other) were evaluated for PS perforations among 6,209 iCT-Navi insertions. We found that 232 (3.7%) screws were judged as major perforations (G2 or G3), 55 (0.9%) screws were judged as dangerous deviations (G3), and seven (0.1%) screws were removed. There were no reports of neurovascular injury caused by PSs. The risk factors for PS perforation included more than six vertebrae distance from the reference frame, more than nine consecutive insertions, upper thoracic level, thinner pedicle, upper instrumented vertebra proximity, short stature, and female. The accuracy of PS insertion did not remarkably decrease when the radiation dose was reduced to 1/5 or 1/10 by altering the iCT-Navi protocol. CONCLUSIONS: iCT-Navi has the potential to reduce PS perforation rates compared with other methods. The use of low-dose radiation protocols may not significantly affect PS perforation rates. Although several risk factors for PS perforation and measures to reduce radiation dose have been reported, the current evidence is limited by a lack of consistency in classifying PS perforation and evaluating patient radiation dose among studies. The standardization of several outcome definitions is recommended in this rapidly developing field.

Surgical results for cervical spondylotic myelopathy with inconsistent between deep tendon reflex findings and magnetic resonance imaging findings.

BACKGROUND: To evaluate the surgical results of patients with cervical spondylotic myelopathy (CSM) with inconsistency between deep tendon reflex findings and cervical magnetic resonance imaging (MRI) findings and to analyze the differences between patients with good and poor surgical outcomes. METHODS: We evaluated 50 subjects with CSM (30 males, 20 females; mean age: 70.4 years) who underwent posterior surgery and were followed for at least 1 year postoperatively. Matched CSM was defined as a consistent preoperative neurological pattern determined by deep tendon reflex and cervical MRI T2-weighted high-signal intramedullary area or stenosis in the most cranial compression levels. A lack of consistency was classified as unmatched CSM. Recovery rate (RR) according to Japanese Orthopaedic Association (JOA) scoring preoperatively and at 1 year postoperatively were compared between the groups. RESULTS: The matched and unmatched CSM group included 27 subjects (13 males, 14 females; mean age: 68.2 years) and 23 subjects (17 males, 6 females; mean age: 72.8 years), respectively. RR was significantly higher in the matched CSM group (56.1 ± 3.7 % vs 36.8 ± 2.7 %; p = 0.002). Unmatched CSM was significantly associated with a lower RR independently of sex, patient age, surgical procedure, preoperative JOA score, diagnosis levels, and complication of diabetes. CONCLUSIONS: Postoperative JOA score RR was significantly diminished among unmatched CSM patients comprising of 46% of cases. Some patients with unmatched CSM had multiple levels of spinal canal stenosis, foraminal stenosis, and peripheral neuropathy, suggesting that surgical results were poorer than those of matched CSM.

Usefulness of modified S-line for upper instrumented vertebra selection in adolescent idiopathic scoliosis Lenke type 2 curves.

No validated systems exist for selecting the upper instrumented vertebra (UIV) for optimal postoperative shoulder balance in Lenke type 2 adolescent idiopathic scoliosis (AIS). This study evaluated a new method for shoulder balance prediction using the modified Shinshu line (MSL) for UIV selection in AIS Lenke type 2 curves. Fifty-five consecutive AIS patients receiving posterior spinal fusion (PSF) for a Lenke type 2 AIS curve were retrospectively analyzed according to several UIV determination models. Shoulder imbalance was judged as absolute radiographic shoulder height ≥ 10 mm at the 2-year observational endpoint. The MSL was the line between the center of the spinous process of C7 and that of the lowest instrumented vertebra. The vertebral body first touched proximally by the MSL was defined as the MSL vertebra (MSLV) and recommended as the UIV. The group with the UIV matching the MSLV had a significantly lower prevalence of shoulder imbalance of 23% (odds ratio 4.08, 95% CI 1.22-13.7, P = 0.02). Setting the MSLV as the UIV in PSF for AIS Lenke type 2 may reduce the prevalence of postoperative shoulder imbalance.

A case of adult-onset Grisel's syndrome.

Aim: Grisel's syndrome is a non-traumatic subluxation of the atlanto-axial joint that occurs after infection or inflammation in the otolaryngological area, primarily in children.Method: This report describes the clinical characteristics of an extremely rare case of adult-onset Grisel's syndrome.Result: A 77-year-old woman presented with neck and bilateral shoulder pain and stiffness. Her temperature was 37.6 °C. Blood testing revealed a mildly elevated inflammatory response, although blood cultures were negative. Computed tomography (CT) showed atlanto-axial subluxation and joint destruction. T2-weighted magnetic resonance imaging (MRI) displayed high signals in the soft tissues in the anterior space of the atlas and axis, posterior wall of the pharynx, and interspinous ligament, indicating spinal cord compression at the C1 level. Differential diagnoses of inflammation and diseases causing atlanto-axial subluxation included rheumatoid arthritis, amyloidosis, pyogenic spondylitis due to posterior pharyngeal abscess, and crowned dens syndrome. After the systematic elimination of each condition, we considered Grisel's syndrome and began non-surgical treatment with intravenous antibiotics and a Philadelphia neck collar. Her inflammatory response and neck pain gradually decreased. Six months later, there was no progression of instability. She was able to walk unaided and live normally with the use of a neck collar as needed.Conclusion: Grisel's syndrome occurs predominantly in children, but can also afflict adults. Since early diagnosis and treatment can improve symptoms in some cases and prevent progressive atlanto-axial instability, prompt evaluation of the atlanto-axial joint using CT or MRI is advised in patients with neck pain and limited range of motion.

Hemoptysis due to progressive scoliosis associated with congenital heart disease: a case report.

BACKGROUND: Patients with congenital heart disease (CHD) are associated with an increased incidence of scoliosis, often with severe progression. We report a case of hemoptysis caused by rapid scoliosis progression subsequent to surgery for CHD that was successfully managed by surgical curve correction following coil embolization. CASE PRESENTATION: A 14-year-old girl with scoliosis had undergone open heart surgery for CHD at the age of 1 year. She was first noted to have scoliosis at 12 years of age, which began to progress rapidly. At age 13, her main thoracic curve Cobb angle was 46°, and hemoptysis with high pulmonary vein pressure due to vertebral rotation was detected. Nine months after coil embolization, she received posterior spinal fusion from T5 to L2 for scoliosis correction. Postoperatively, her pulmonary vein diameter was enlarged, with no detectable signs of hemoptysis. CONCLUSIONS: We encountered a case of hemoptysis caused by advanced scoliosis after cardiac surgery that was successfully treated by correction of the scoliotic curve following coil embolization. Patients with secondary scoliosis after surgery for CHD should be carefully monitored for the possibility of cardiovascular system deterioration.

How much residual deformity is acceptable according to SRS-22r and satisfaction scores after posterior spinal fusion for Lenke type 1 and 2 curves in adolescent idiopathic scoliosis?

OBJECTIVE: In recent years, it has become possible to predict postoperative correction and residual deformity in adolescent idiopathic scoliosis (AIS) surgery based on the technique used and extent of fixation. However, the recommended degree of correction has not yet been established. In this study, the authors aimed to clarify the extent to which a residual postoperative deformity would be acceptable according to Scoliosis Research Society (SRS)-22r and satisfaction scores after AIS surgery. METHODS: Overall, 92 patients who underwent posterior spinal fusion for Lenke type 1 or 2 AIS were retrospectively included. The Patient Acceptable Symptom State (PASS) cutoff values for each SRS-22r domain were calculated using receiver operating characteristic (ROC) curves to obtain predictive values of treatment satisfaction 2 years after surgery. Multivariate logistic regression analysis was performed with deformity parameters and demographic data as explanatory variables, and achieving the PASS cutoff value of each SRS-22r domain and treatment satisfaction were objective variables. Cutoff values were calculated using ROC analysis. RESULTS: The PASS cutoff values for SRS-22r domains were 3.69 (area under the ROC curve [AUC] 0.86) for self-image, 4.25 (AUC 0.82) for mental health, and 4.22 (AUC 0.82) for the subtotal. The residual main thoracic Cobb angle was not remarkably related to SRS-22r or treatment satisfaction. The residual thoracolumbar/lumbar (TL/L) Cobb angle was significantly associated with treatment satisfaction, with a cutoff value of 12.5° (AUC 0.75). The parameters of deformity that were significantly associated with achieving the PASS cutoff value for self-image were the TL/L Cobb angle and main thoracic apical vertebral translation, although their respective AUCs were < 0.7. CONCLUSIONS: In patients with Lenke type 1 and 2 AIS, the residual postoperative TL/L Cobb angle was significantly associated with achieving the PASS cutoff values for self-image and treatment satisfaction. Satisfaction with treatment was more likely when the TL/L Cobb angle was ≤ 12.5°.

Frequency of Change in Assessment from Bony Union to Nonunion after Lumbar Interbody Fusion: A Multicenter Study.

INTRODUCTION: Assessments of early postoperative bony union after posterior lumbar interbody fusion via computed tomography (CT) have revealed cases in which interbody fixation by bony union resulted in nonfusion due to bone absorption. The apparent bone union state reverted to a nonunion state several months later, exhibiting a so-called "fake union" phenomenon. Additionally, few reports have evaluated the effect of teriparatide on bony union. The present study aimed to evaluate the frequency of change in assessment from fusion to nonfusion in the postoperative follow-up of lumbar interbody fusion, compare the late postoperative bony union rates in groups with or without early postoperative fusion, and examine the effect of postoperative teriparatide in those groups. METHODS: Sixty-nine subjects enrolled from multiple hospitals were prospectively evaluated following single-level lumbar interbody fusion. The patients were randomly allocated into treatment with or without weekly postoperative teriparatide. The subjects were then classified as having bony union or nonfusion at 2 months postoperatively, and fusion rates at 6 months were compared. For the evaluation of bony union, blinded radiological examinations were performed via CT. Additional comparisons were made according to teriparatide use. RESULTS: The rate of nonunion at 6 months postoperatively in patients with fusion at 2 months postoperatively was 27.8%. Among subjects with bony union at 2 months postoperatively, the fusion rate at 6 months in those who received teriparatide was 93.3% (p=0.027) versus 57.1% in those who did not. CONCLUSIONS: The rate of nonunion at 6 months postoperatively in patients exhibiting union at 2 months after surgery was 27.8%. Postoperative weekly teriparatide treatment significantly reduced the rate of fake union.

Comparison of differences and random errors in pedicle diameter measurements between MRI and CT: observational study of 315 pedicles in Lenke type 1 adolescent idiopathic scoliosis patients.

BACKGROUND CONTEXT: Posterior spinal fusion with pedicle screws is commonly used for the treatment of adolescent idiopathic scoliosis (AIS). To reduce radiation exposure, methods other than computed tomography (CT) are desirable for preoperative determination of pedicle diameter. PURPOSE: Investigate the differences between magnetic resonance imaging (MRI) and CT measurements of pedicle diameter. STUDY DESIGN: Cross-sectional research. PATIENT SAMPLE: Twenty-one AIS Lenke type 1 patients (19 female and 2 males, mean age at surgery: 15.4 years) who underwent posterior spinal fusion between April 2009 and October 2019. OUTCOME MEASURES: Gap between CT and MRI pedicle diameters. METHODS: The inner and outer diameters of the right and left pedicles from T1 to L3 were measured separately by two spine surgeons for statistical comparisons. RESULTS: The respective minimum and maximum CT-MRI values were -3.7 mm and 4.7 mm for inner diameter and -4.6 mm and 5.3 mm for outer diameter. Regarding inter-examiner error, the probability of a 2 mm difference in measurement was less than 5% for both modalities. The probability of a 1 mm difference was also less than 5%, and that of a 3 mm or more difference was 2.1% for the inner diameter and 2.9% for the outer diameter. Whereas low body weight was significantly associated with measurement differences, pedicle laterality was not. CONCLUSIONS: MRI does not have the reliability to measure pedicle size in AIS patients at present. However, with advancements in image processing technology, the accuracy of pedicle size measurement by MRI may soon improve.

Intraoperative Cone Beam CT in Hybrid Operation Room for Pediatric Scoliosis Patients: Comparison of Pedicle Screw Violation Rate at Normal and Low Radiation Doses.

STUDY DESIGN: Retrospective observational study. OBJECTIVE: This study aimed to determine the effect of reducing the radiation dose of intraoperative cone beam computed tomography (CBCT) during posterior spinal fusion (PSF) for pediatric scoliosis on the rate of pedicle screw (PS) violation. SUMMARY OF BACKGROUND DATA: Intraoperative CBCT for pediatric scoliosis improves the accuracy of PS insertion in PSF. However, few reports have addressed the PS perforation rate from reduced radiation doses in hybrid navigation. METHODS: We evaluated 855 PSs inserted into 58 pediatric scoliosis patients (11 male and 47 female, mean age: 16.6 yr) who underwent PSF using CBCT. A radiation dose of 1/3 or 1/5 of the normal dose (ND) was defined as a low dose (LD). After PS insertion, intraoperative CBCT images were reviewed to assess the degree of PS perforation. G2-3 (i.e., perforations of 4 mm or more) was defined as a violation. The PS violation rate was compared between the groups, and factors associated with violations were examined. RESULTS: A total of 567 and 288 screws were inserted in the ND group and LD group, respectively. The PS violation rate was comparable at 1.8% in the ND group and 1.7% in the LD group. Multiple logistic regression analysis showed that distance from the upper instrumented vertebra (UIV) was an independently associated factor of PS violation (+1 vertebra, operation room 0.73, P   =  0.038). In addition, the mean height of patients with PS violations (148.8 ±â€Š3.6 cm) was significantly shorter than that of patients without violations (157.9 ±â€Š1.2 cm) ( P  = 0.034). CONCLUSION: There was no increase in PS violation rate with lower doses of radiation for intraoperative navigation CBCT. Extra care is warranted for vertebrae close to the UIV and patients of shorter stature.Level of Evidence: 3.

Pre-operative angle of trunk rotation in prone position estimates postoperative correction results.

ABSTRACT: This study investigated whether postoperative rotational deformity in adolescent idiopathic scoliosis patients could be predicted by prone-position pre-operative angle of trunk rotation (ATR).Surgical rib hump correction is performed with the patient in a prone position. However, the association between pre-operative ATR in the prone position and postoperative ATR results is unknown.Thirty-four consecutive patients who underwent skip pedicle screw fixation for Lenke type 1 or 2 adolescent idiopathic scoliosis were retrospectively reviewed. All subjects were followed for a minimum of 1 year. ATR measurements were taken for the standing-flexion position with a scoliometer before surgery and at 1 year afterward. Pre-operative measurements were also taken for the prone position. Correlations between pre- and postoperative ATR were calculated by means of Pearson correlation coefficient. Associations between the correction angle from the standing-flexion position to prone position and postoperative standing-flexion correction angle were determined by linear regression analysis.Pre- and postoperative ATR for the standing-flexion position showed a moderate association (r = 0.64, P < .01). A similar correlation was seen for pre-operative prone-position ATR and postoperative standing-flexion ATR (r = 0.56, P < .01). In linear regression analysis, there was significant proportional error between the correction angle from the standing-flexion position to prone position and postoperative standing-flexion correction angle (ß = 0.40, P < .01).In conclusion, pre-operative ATR in either standing-flexion or prone position and postoperative standing-flexion ATR displayed moderate associations. Linear regression analysis revealed that ATR correction angle could be estimated by calculating the correction gains of 0.4° per 1° of correction angle in the prone position.