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Delayed post-operative spinal epidural haematoma (DPSEH) is diagnosed when the onset of symptoms is more than three days from the index surgery. DPSEH is a rare but serious complication of spinal surgery. Missed diagnosis will result in irreversible neurological deficit which may lead to permanent disabilities. We report two cases of DPSEH who presented with worsening neurological deficit four days after the index surgery. Magnetic resonance imaging (MRI) showed the presence of an epidural haematoma compressing the spinal cord. Surgical evacuation of haematoma were performed for both patients. Both patients experienced neurological improvement. Surgeons should have high index of suspicion to identify delayed onset of spinal epidural haematoma (SEH) and timely intervention should be taken to avoid irreversible neurological damage., (© 2020 Malaysian Orthopaedic Association (MOA). All Rights Reserved.)

Study Design: Cross-sectional survey., Objective: The aim of this study was to investigate the impact of COVID-19 pandemic on the clinical practices of spine surgeons within the Asia Pacific region., Summary of Background Data: COVID-19 pandemic had changed spine surgeons' clinical practices and their concerns toward personal and family risk of infection., Methods: This cross-sectional survey was carried out from May 4, 2020 to June 4, 2020. The questionnaire was administered using REDCAP. The online questionnaire includes four sections. First section includes surgeon's demographics, background, type of clinical practice, and status of pandemic in their country. Second section includes volume and the type of spine surgery practice before the COVID pandemic. Third section includes changes of clinical practice during the pandemic and the last section was regarding their concern on COVID transmission., Results: Total of 222 respondents from 19 countries completed the questionnaire. During the pandemic, 92.3% of the respondents felt their clinical practice was affected. 58.5% respondents reported reduced outpatient clinic hours and 74.6% respondents reported reduced operation theatre hours due to the enforcement by the hospital administration. The mean reduction of clinic volume for all countries was 48.1%. There was a significant reduction in the number of surgeries performed in Japan, Malaysia, India, Philippines, and South Korea. This was due to reduced patient load. More than 60% of respondents were worried being infected by COVID-19 virus and >68% were worried of transmission to their family members., Conclusion: COVID-19 pandemic has significantly affected the clinical and surgical practice of spine surgeons in the Asia Pacific region. Clinics were closed or the practice hours reduced. Similarly, surgical theaters were closed, reduced, or limited to semi-emergency and emergency surgeries. Spine surgeons were moderately concerned of contracting COVID-19 during their clinical practice but were extremely concerned to transmit this disease to their family members., Level of Evidence: 4.

Purpose: Various surgical strategies including combined approach and spinal osteotomies in severe rigid scoliosis had been reported with significant perioperative complication rates. The use of single-staged posterior spinal fusion (PSF) utilizing a dual attending surgeon strategy for severe rigid scoliosis has not been widely reported., Methods: This was a retrospective study aimed to evaluate the perioperative outcome of single-staged PSF in severe rigid idiopathic scoliosis patients (Cobb angle ≥90° and ≤30% flexibility). Forty-one patients with severe rigid idiopathic scoliosis who underwent single-staged PSF were included. The perioperative outcome parameters were operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, preoperative and postoperative hemoglobin, transfusion rate, patient-controlled anesthesia morphine usage, length of postoperative hospital stay, and perioperative complications. Radiological parameters included preoperative and postoperative Cobb angle, correction rate, side-bending flexibility, and side-bending correction index., Results: The mean age was 16.9 ± 5.6 years. The mean preoperative Cobb angle was 110.8 ± 12.1° with mean flexibility of 23.1 ± 6.3%. The mean operation duration was 215.5 ± 45.2 min with mean blood loss of 1752.6 ± 830.5 mL. The allogeneic blood transfusion rate was 24.4%. The mean postoperative hospital stay was 76.9 ± 26.7 h. The mean postoperative Cobb angle and correction rate were 54.4 ± 12.8° and 50.9 ± 10.1%, respectively. The readmission rate in this cohort was 2.4%. Four perioperative complications were documented (9.8%), one somatosensory evoke potential signal loss, one superficial infection, one lung collapse, and one superior mesenteric artery syndrome., Conclusions: Severe rigid idiopathic scoliosis treated with single-staged PSF utilizing a dual attending surgeon strategy demonstrated an average correction rate of 50.9%, operation duration of 215.5 min, and postoperative hospital stay of 76.9 h with a 9.8% perioperative complication rate.

Superior mesenteric artery (SMA) syndrome is a rare but serious complication following scoliosis surgery. Early diagnosis and management are key factors for successful conservative treatment to avoid the need for emergency laparotomies which causes higher morbidity or even mortality. We report two adolescent idiopathic scoliosis patients with Cobb angle of 49° and 132°, respectively, and low body mass index who presented with SMA syndrome following posterior spinal fusion from T2 to L3 and were treated successfully with conservative management. Abdominal radiographs showed distended gastric shadow. Computed tomography angiography of the abdomen showed decreased aortomesenteric angle and SMA-aorta distance. Both patients were treated successfully with conservative treatment which included three principles: gastric decompression with nasogastric tube, correction of electrolytes imbalance, and nutritional support with low volume, high calorie nutritional supplement. Both patients were started with small but frequent meals. Surgeries were not required in both cases. Early diagnosis and management are the key factors to successful treatment in SMA syndrome. Patients with SMA can be treated successfully with conservative treatment comprising of nasogastric decompression, electrolyte correction, and nutritional support with small but frequent meals.

Growth hormone secreting pituitary tumor or gigantism has not been previously reported to be associated with rapid progression of scoliosis in the literature. However, there are some reports indicating scoliosis can be worsened by growth hormone therapy in children and adolescents. A 19-year-old boy was referred to our institution for the treatment of a right thoracolumbar scoliosis. The Cobb angle had worsened from 29° to 83° over two years' duration. He attained puberty at the age of 13. He had a previous history of slipped upper femoral epiphysis (SUFE), which was operated in 2015, with no clinical features of gigantism. Preoperative assessment was performed. He was diagnosed with growth hormone secreting pituitary macroadenoma by magnetic resonance imaging with a high serum level of insulin-like growth factor-I (IGF-I). Computed tomography (CT) of the pancreas showed a pancreatic endocrine tumor. The patient was later diagnosed with multiple endocrine neoplasia type 1 (MEN 1). He underwent endoscopic endonasal excision of the pituitary mass and distal pancreatectomy. This case indicates that growth hormone secreting pituitary macroadenoma could result in rapid progression of scoliosis.

Objective: The incidence of postoperative shoulder imbalance following posterior spinal fusion (PSF) is still high in Lenke 1 curves despite following current treatment recommendations for upper instrumented vertebra (UIV) selection. The objective of this retrospective study was to identify differences in preoperative shoulder balance and to report the surgical outcome of two subtypes of Lenke 1 curves (flexible vs stiff) in patients with adolescent idiopathic scoliosis (AIS)., Methods: The authors grouped patients' curves as Lenke 1-ve (flexible) when their preoperative proximal thoracic side bending (PTSB) Cobb angle was < 15° and as Lenke 1+ve (stiff) when the PTSB Cobb angle was 15°-24.9°. The authors hypothesized that these two subtypes had distinct preoperative and postoperative shoulder and neck balance following PSF using pedicle screw constructs., Results: Fifty patients had Lenke 1 (flexible) curves and 61 had Lenke 1 (stiff) curves. The mean preoperative T1 tilt for patients with Lenke 1 (flexible) was -4.9° ± 5.3°, and for those with Lenke 1 (stiff) curves it was -1.0° ± 5.3° (p < 0.001). Mean cervical axis (CA) was -0.1° ± 3.2° for Lenke 1 (flexible) curves and 2.3° ± 3.5° for Lenke 1 (stiff) curves (p < 0.001). Preoperative radiographic shoulder height (RSH) and clavicle angle (Cla-A) were similar between the two curve subtypes. Following surgery, there were significant differences between the subtypes in terms of T1 tilt (p < 0.001), RSH (p = 0.014), and Cla-A (p = 0.031). Interestingly, 41.0% of patients with a Lenke 1 (stiff) curve had +ve T1 tilt compared to 2.0% in Lenke 1 (flexible) group. Moreover, 26.2% of patients with the Lenke 1 (stiff) curve had +ve RSH compared to 12.0% of those with Lenke 1 (flexible) curves. And, 24.6% of patients with Lenke 1 (stiff) had +ve Cla-A compared to 10.0% of those with Lenke 1 (flexible) curves., Conclusions: Lenke 1 (flexible) and Lenke 1 (stiff) curves had distinct preoperative T1 tilt and CA measurements. Following PSF, the authors noted +ve T1 tilt in 41% of patients with Lenke 1 (stiff) curves versus 2.0% in those with Lenke 1 (flexible) curves. The authors also noted a significant difference in postoperative RSH and Cla-A measurements.

Study Design: Retrospective propensity score matching study., Objective: To investigate whether menses affect intraoperative blood loss in female adolescent idiopathic scoliosis (AIS) patients undergoing posterior spinal fusion (PSF) surgeries., Summary of Background Data: There were concerns whether patients having menses will have higher intraoperative blood loss if surgery were to be done during this period., Methods: This study included 372 females who were operated between May 2016 to May 2019. Fifty-five patients had menses during surgery (Group 1, G1) and 317 patients did not have menses during surgery (Group 2, G2). Propensity score matching (PSM) analysis with one-to-one, nearest neighbor matching technique and with a match tolerance of 0.001 was used. The main outcome measures were intraoperative blood loss (IBL), volume of blood salvaged, transfusion rate, preoperative hemoglobin, preoperative platelet, preoperative prothrombin time, preoperative activated partial thromboplastin time (APTT), international normalized ratio (INR), and postoperative hemoglobin. Postoperative Cobb angle and correction rate were also documented., Results: At the end of PSM analysis, 46 patients from each group were matched and balanced. The average operation duration for G1 was 140.8 ± 43.0 minutes compared with 143.1 ± 48.3 minutes in G2 (P = 0.806). The intraoperative blood loss for G1 was 904.3 ± 496.3 mL and for G2 was 907.9 ± 482.8 mL (P = 0.972). There was no significant difference in terms of normalized blood loss (NBL), volume of blood salvaged during surgery, preoperative hemoglobin, postoperative hemoglobin, hemoglobin drift, estimated blood volume (EBV), IBL per EBV and IBL per level fused (P > 0.05). No postoperative complications were encountered in both groups. On average, the postoperative hospital stay was 3.5 ± 0.8 days for both groups (P = 0.143)., Conclusion: Performing corrective surgery during the menstrual phase in female AIS patients is safe without risk of increased blood loss., Level of Evidence: 4.

Study Design: Multicenter validation study., Purpose: To evaluate the inter-rater reliability of Rajasekaran's kyphosis classification through a multicenter validation study., Overview of Literature: The classification of kyphosis, developed by Rajasekaran, incorporates factors related to curve characteristics, including column deficiency, disc mobility, curve magnitude, and osteotomy requirements. Although the classification offers significant benefits in determining prognosis and management decisions, it has not been subjected to multicenter validation., Methods: A total of 30 sets of images, including plain radiographs, computed tomography scans, and magnetic resonance imaging scans, were randomly selected from our hospital patient database. All patients had undergone deformity correction surgery for kyphosis. Twelve spine surgeons from the Asia-Pacific region (six different countries) independently evaluated and classified the deformity types and proposed their surgical recommendations. This information was then compared with standard deformity classification and surgical recommendations., Results: The kappa coefficients for the classification were as follows: 0.88 for type 1A, 0.78 for type 1B, 0.50 for type 2B, 0.40 for type 3A, 0.63 for type 3B, and 0.86 for type 3C deformities. The overall kappa coefficient for the classification was 0.68. Regarding the repeatability of osteotomy recommendations, kappa values were the highest for Ponte's (Schwab type 2) osteotomy (kappa 0.8). Kappa values for other osteotomy recommendations were 0.52 for pedicle subtraction/disc-bone osteotomy (Schwab type 3/4), 0.42 for vertebral column resection (VCR, type 5), and 0.30 for multilevel VCRs (type 6)., Conclusions: Excellent accuracy was found for types 1A, 1B, and 3C deformities (ends of spectrum). There was more variation among surgeons in differentiating between one-column (types 2A and 2B) and two-column (types 3A and 3B) deficiencies, as surgeons often failed to recognize the radiological signs of posterior column failure. This failure to identify column deficiencies can potentially alter kyphosis management. There was excellent consensus among surgeons in the recommendation of type 2 osteotomy; however, some variation was observed in their choice for other osteotomies.

Background Context: Biopsy is important to obtain microbiological and histopathological diagnosis in spine infections and tumors. To date, there have been no prospective randomized trials comparing fluoroscopic guided and computed tomography (CT) transpedicular biopsy techniques. The goal of this study was to evaluate the accuracy, safety, and diagnostic outcome of these two diagnostic techniques., Purpose: To evaluate the accuracy, safety, and diagnostic outcome of fluoroscopic guided and CT transpedicular biopsy techniques., Study Design: Prospective randomized trial., Patient Sample: Sixty consecutive patients with clinical symptoms and radiological features suggestive of spinal infection or malignancy were recruited and randomized into fluoroscopic or CT guided spinal biopsy groups. Both groups were similar in terms of patient demographics, distribution of spinal infections and malignancy cases, and the level of biopsies., Outcome Measures: The primary outcome measure was diagnostic accuracy of both methods, determined based on true positive, true negative, false positive, and false negative biopsy findings. Secondary outcome measures included radiation exposure to patients and doctors, complications, and postbiopsy pain score., Methods: A transpedicular approach was performed with an 8G core biopsy needle. Specimens were sent for histopathological and microbiological examinations. Diagnosis was made based on biopsy results, clinical criteria and monitoring of disease progression during a 6-month follow up duration. Clinical criteria included presence of risk factors, level of inflammatory markers and magnetic resonance imaging findings. Radiation exposure to patients and doctors was measured with dosimeters., Results: There was no significant difference between the diagnostic accuracy of fluoroscopic and CT guided spinal biopsy (p=0.67) or between the diagnostic accuracy of spinal infection and spinal tumor in both groups (p=0.402 for fluoroscopy group and p=0.223 for CT group). Radiation exposure to patients was approximately 26 times higher in the CT group. Radiation exposure to doctors in the CT group was approximately 2 times higher compared to the fluoroscopic group if a lead shield was not used. Lead shields significantly reduced radiation exposure to doctors anywhere from 2 to 8 times. No complications were observed for either group and the differences in postbiopsy pain scores were not significant., Conclusions: The accuracy, procedure time, complication rate and pain score for both groups were similar. However, radiation exposure to patients and doctors were significantly higher in the CT group without lead protection. With lead protection, radiation to doctors reduced significantly., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Study Design: Retrospective study., Objective: To investigate the relationship between a +ve postoperative Upper Instrumented Vertebra (UIV) (≥0°) tilt angle and the risk of medial shoulder/neck and lateral shoulder imbalance among Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) patients following Posterior Spinal Fusion., Summary of Background Data: Current UIV selection strategy has poor correlation with postoperative shoulder balance. The relationship between a +ve postoperative UIV tilt angle and the risk of postoperative shoulder and neck imbalance was unknown., Methods: One hundred thirty-six Lenke 1 and 2 AIS patients with minimum 2 years follow-up were recruited. For medial shoulder and neck balance, patients were categorized into positive (+ve) imbalance (≥+4°), balanced, or negative (-ve) imbalance (≤-4°) groups based on T1 tilt angle/Cervical Axis measurement. For lateral shoulder balance, patients were classified into +ve imbalance (≥+3°) balanced, and -ve imbalance (≤-3°) groups based on Clavicle Angle (Cla-A) measurement. Linear regression analysis identified the predictive factors for shoulder/neck imbalance. Logistic regression analysis calculated the odds ratio of shoulder/neck imbalance for patients with +ve postoperative UIV tilt angle., Results: Postoperative UIV tilt angle and preoperative T1 tilt angle were predictive of +ve medial shoulder imbalance. Postoperative UIV tilt angle and postoperative PT correction were predictive of +ve neck imbalance. Approximately 51.6% of patients with +ve medial shoulder imbalance had +ve postoperative UIV tilt angle. Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance and 3.3 times increased odds of developing +ve neck imbalance. Postoperative UIV tilt angle did not predict lateral shoulder imbalance., Conclusion: Patients with +ve postoperative UIV tilt angle had 14.9 times increased odds of developing +ve medial shoulder imbalance (T1 tilt angle ≥+4°) and 3.3 times increased odds of developing +ve neck imbalance (cervical axis ≥+4°)., Level of Evidence: 4.

Study Design: Retrospective study., Objective: The primary objective of this study was to assess the conformity of the radiological neck and shoulder balance parameters throughout a follow-up period of more than 2 years., Summary of Background Data: Postoperative shoulder and neck imbalance are undesirable features among Adolescent Idiopathic Scoliosis patients who underwent Posterior Spinal Fusion. There are many clinical and radiological parameters used to assess this clinical outcome. However, we do not know whether these radiological parameters conform throughout the entire follow-up period., Methods: This was a retrospective study done in a single academic institution. Inclusion criteria were patients with scoliosis who underwent posterior instrumented spinal fusion with pedicle screw fixation and attended all scheduled follow-ups for at least 24 months postoperatively. Radiological shoulder parameters were measured from both preoperative antero-posterior and postoperative antero-posterior radiographs. Lateral shoulder parameters were: Radiographic Shoulder Height, Clavicle Angle (Cla-A), Clavicle-Rib Intersection Difference, and Coracoid Height Difference. Medial shoulder and neck parameters were: T1 Tilt and Cervical Axis (CA)., Results: The radiographs of 50 patients who had surgery done from November 2013 to November 2015 were analyzed. Mean age of this cohort was 16.3 ± 7.0 years. There were 38 (76%) female patients and 12 (24%) male patients. Mean final follow-up was 38.6 ± 5.8 months. When conformity assessment of the radiological parameter using the interclass coefficient correlation was done, we found that all parameters had significant correlation (P < 0.05). T1 tilt (0.78) had good reliability, CA (0.47), Clavicle-Rib Intersection Difference (0.43), and Coracoid Height Difference (0.40) had moderate reliability and Radiographic Shoulder Height (0.22) and Cla-A (0.13) had poor reliability., Conclusion: All the radiological shoulder and neck balance parameters studied were conformed and suitable to be used to assess the patient postoperatively. Amongst these radiological parameters, T1 tilt followed by CA recorded to be the most reliable parameters over time., Level of Evidence: 4.

Study Design: Retrospective study from a prospectively collected database., Objective: To compare the perioperative outcome between after-hours and daytime surgery carried out by a dedicated spinal deformity team for severe Idiopathic Scoliosis (IS) patients with Cobb angle ≥ 90°., Summary of Background Data: There were concerns that after-hours corrective surgeries in severe IS have higher morbidity compared to daytime surgeries., Methods: Seventy-one severe IS patients who underwent single-staged Posterior Spinal Fusion (PSF) were included. Surgeries performed between 08:00H and 16:59H were classified as "daytime" group and surgeries performed between 17:00H and 06:00H were classified as "after-hours" group. Perioperative outcome parameters were average operation start time and end time, operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, preoperative and postoperative hemoglobin, blood transfusion rate, total patient-controlled anesthesia (PCA) morphine usage, length of postoperative hospitalization, and complications. Radiological variables assessed were preoperative and postoperative Cobb angle, side bending flexibility, number of fusion levels, number of screws used, Correction Rate, and Side Bending Correction Index., Results: Thirty patients were operated during daytime and 41 patients were operated after-hours. The mean age was 16.1 ± 5.8 years old. The mean operation start time for daytime group was 11:31 ± 2:45H versus 19:10 ± 1:24H for after-hours group. There were no significant differences between both groups in the operation duration, intraoperative blood loss, intraoperative hemodynamic parameters, postoperative hemoglobin, hemoglobin drift, transfusion rate, length of postoperative hospitalization, postoperative Cobb angle, Correction Rate, and Side Bending Correction Index. There were four complications (1 SSEP loss, 1 massive blood loss, and 2 superficial wound infections) with no difference between daytime and after-hours group., Conclusion: After-hours elective spine deformity corrective surgeries in healthy ambulatory patients with severe IS performed by a dedicated spinal deformity team using dual attending surgeon strategy were as safe as those performed during daytime., Level of Evidence: 4.

Introduction: This study looked into the different anatomical locations of pain and their trajectories within the first two weeks after Posterior Spinal Fusion (PSF) surgery for Adolescent Idiopathic Scoliosis (AIS)., Methods: We prospectively recruited patients with Adolescent Idiopathic Scoliosis (AIS) scheduled for PSF surgery. The anatomical locations of pain were divided into four: (1) surgical wound pain; (2) shoulder pain; (3) neck pain; and (4) low back pain. The anatomical locations of pain were charted using the visual analogue pain score at intervals of 12, 24, 36, 48 hours; and from day-3 to -14. Patient-controlled analgesia (morphine), use of celecoxib capsules, acetaminophen tablets and oxycodone hydrochloride capsule consumption were recorded., Results: A total of 40 patients were recruited. Patients complained of surgical wound pain score of 6.2±2.1 after surgery. This subsequently reduced to 4.2±2.0 by day-4, and to 2.4±1.3 by day-7. Shoulder pain scores of symptomatic patients peaked to 4.2±2.7 at 24 hours and 36 hours which then reduced to 1.8±1.1 by day-8. Neck pain scores of symptomatic patients reduced from 4.2±1.9 at 12 hours to 1.8±1.1 by day-4. Low back pain scores of symptomatic patients reduced from 5.3±2.3 at 12 hours to 1.8±1.1 by day- 12., Conclusions: Despite the presence of different anatomical locations of pain after surgery, surgical wound was the most significant pain and other anatomical locations of pain were generally mild. Surgical wound pain reduced to a tolerable level by day-4 when patients can then be comfortably discharged. This finding provides useful information for clinicians, patients and their caregivers.

Purpose: To determine consensus among Asia-Pacific surgeons regarding nonoperative management for adolescent idiopathic scoliosis (AIS)., Methods: An online REDCap questionnaire was circulated to surgeons in the Asia-Pacific region during the period of July 2019 to September 2019 to inquire about various components of nonoperative treatment for AIS. Aspects under study included access to screening, when MRIs were obtained, quality-of-life assessments used, role of scoliosis-specific exercises, bracing criteria, type of brace used, maturity parameters used, brace wear regimen, follow-up criteria, and how braces were weaned. Comparisons were made between middle-high income and low-income countries, and experience with nonoperative treatment., Results: A total of 103 responses were collected. About half (52.4%) of the responders had scoliosis screening programs and were particularly situated in middle-high income countries. Up to 34% obtained MRIs for all cases, while most would obtain MRIs for neurological problems. The brace criteria were highly variable and was usually based on menarche status (74.7%), age (59%), and Risser staging (92.8%). Up to 52.4% of surgeons elected to brace patients with large curves before offering surgery. Only 28% of responders utilized CAD-CAM techniques for brace fabrication and most (76.8%) still utilized negative molds. There were no standardized criteria for brace weaning., Conclusion: There are highly variable practices related to nonoperative treatment for AIS and may be related to availability of resources in certain countries. Relative consensus was achieved for when MRI should be obtained and an acceptable brace compliance should be more than 16 hours a day.

Purpose: To describe the reduction technique of thoracolumbar burst fracture using percutaneous monoaxial screws and its radiological outcomes compared to polyaxial screws., Methods: All surgeries were performed by minimally invasive technique with either percutaneous monoaxial or percutaneous polyaxial screws inserted at adjacent fracture levels perpendicular to both superior end plates. Fracture reduction is achieved with adequate rod contouring and distraction maneuver. Radiological parameters were measured during preoperation, postoperation, and follow-up., Results: A total of 21 patients were included. Eleven patients were performed with monoaxial pedicle screws and 10 patients performed with polyaxial pedicle screws. Based on AO thoracolumbar classification system, 10 patients in the monoaxial group had A3 fracture type and 1 had A4. In the polyaxial group, six patients had A3 and four patients had A4. Total correction of anterior vertebral height (AVH) ratio was 0.30 ± 0.10 and 0.08 ± 0.07 in monoaxial and polyaxial groups, respectively ( p < 0.001). Total correction of posterior vertebral height (PVH) ratio was 0.11 ± 0.05 and 0.02 ± 0.02 in monoaxial and polyaxial groups, respectively ( p < 0.001). Monoaxial group achieved more correction of 13° (62.6%) in local kyphotic angle compared to 8.2° (48.0%) in polyaxial group. Similarly, in regional kyphotic angle, 16.5° (103.1%) in the monoaxial group and 8.1° (76.4%) in the polyaxial group were achieved., Conclusions: Monoaxial percutaneous pedicle screws inserted at adjacent fracture levels provided significantly better fracture reduction compared to polyaxial screws in thoracolumbar fractures.

Aberrant left brachiocephalic vein is a rare condition. Its occurrence in patients requiring anterior cervicothoracic approach for severe kyphoscoliosis has not been described. A 16-year-old male with neurofibromatosis and severe upper thoracic kyphoscoliosis presented to us with curve progression. Halo gravity traction was attempted but failed to achieve significant correction. Subsequently, he underwent halo-pelvic traction and later Posterior Spinal Fusion (PSF) from C2 to T10. Second-stage anterior cervicothoracic approach with anterior fibula strut grafting was planned; however, preoperative computed tomography angiography revealed an aberrant left brachiocephalic vein with an anomalous retrotracheal and retroesophageal course, directly anterior to the T5/T6 vertebrae (planned anchor site for fibula strut graft) before draining into superior vena cava. Therefore, surgery was abandoned due to the risks associated with this anomaly. Aberrant left brachiocephalic vein is rare, the presence of which could be a contraindication for anterior cervicothoracic approach. Assessment of the anterior neurovascular structures is crucial in preoperative planning.

Study Design: Retrospective study., Objective: This study looked into whether crossbar can reliably measure Upper Instrumend Vertebra (UIV) tilt angle intraoperatively and accurately predict the UIV tilt angle postoperatively and at final follow-up., Summary of Background Data: Postoperative shoulder imbalance is a common cause of poor cosmetic appearance leading to patient dissatisfaction. There were no reports describing the technique or method in measuring the UIV tilt angle intraoperatively. Therefore, this study was designed to look into the reliability and accuracy of the usage of intraoperative crossbar in measuring the UIV tilt angle intraoperatively., Methods: Lenke 1 and 2 Adolescent Idiopathic Scoliosis patients who underwent instrumented Posterior Spinal Fusion using pedicle screw constructs with minimum follow-up of 24 months were recruited for this study. After surgical correction, intraoperative UIV tilt angle was measured using a crossbar. Immediate postoperative and final follow up UIV tilt angle was measured on the standing anteroposterior radiographs., Results: A total of 100 patients were included into this study. The reliability of the intraoperative crossbar to measure the optimal UIV tilt angle intraoperatively was determined by repeated measurements by assessors and measurement by different assessors. We found that the intra observer and inter observer reliability was very good with intraclass correlation coefficient values of >0.9. The accuracy of the intraoperative crossbar to measure the optimal UIV tilt angle intraoperatively was determined by comparing this measurement with the postoperative UIV tilt angle. We found that there was no significant difference (P>0.05) between intraoperative, immediate postoperative, and follow-up UIV tilt angle., Conclusions: The crossbar can be used to measure the intraoperative UIV tilt angle consistently and was able to predict the postoperative UIV tilt angle. It was a cheap, simple, reliable, and accurate instrument to measure the intraoperative UIV tilt angle.

Study Design: Retrospective study of a prospectively-collected data., Objective: To determine whether the severity of the curve magnitude in Lenke 1 and 2 Adolescent Idiopathic Scoliosis (AIS) patients affects the distance and position of the aorta from the vertebra., Summary of Background Data: There were studies that looked into the position of the aorta in scoliotic patients but none of them documented the change in distance of the aorta to the vertebra in relation to the magnitude of the scoliosis., Methods: Patients with Lenke 1 and 2 AIS who underwent posterior spinal fusion using pedicle screw construct and had a preoperative computed tomography (CT) scan performed were recruited. The radiological parameters measured on preoperative CT scan were: Aortic-Vertebral Distance (AVD), Entry-Aortic Distance (EAD), Aortic-Vertebral angle (AVA), Pedicle Aorta angle/Aortic Alpha angle (α angle), and Aortic Beta angle (β angle)., Results: Thirty-nine patients were recruited. Significant moderate to strong positive correlation was found between AVD and Cobb angle from T8 to T12 vertebrae (r = 0.360 to 0.666). The EAD was generally small in the thoracic region (T4-T10) with mean EAD of less than 30 mm. Among all apical vertebrae, the mean AVD was 5.9 ± 2.2 mm with significant moderate-strong positive correlation to Cobb angle (r = 0.580). The mean α angle was 37.7 ± 8.7° with significant weak positive correlation with Cobb angle (r = 0.325)., Conclusion: The larger the scoliotic curve, the aorta was located further away from the apical vertebral wall. The aorta has less risk of injury from the left lateral pedicle screw breach in larger scoliotic curve at the apical region. The distance from the pedicle screw entry point to the wall of the aorta was generally small (less than 30 mm) in the thoracic region (T4-T10)., Level of Evidence: 4.

The presence of anatomical anomalies such as absence of C1 posterior arch and presence of C2 high-riding vertebral artery may not allow a conventional C1-C2 fusion, and this patient will require occipitocervical fusion. A 62-year-old lady presented with cervical myelopathy. CT scan demonstrated an os odontoideum with C1-C2 dislocation. The posterior arch of atlas on right C1 vertebra was absent, and there was high-riding vertebral artery on left C2. MRI revealed severe cord compression with cord oedema. The chronic atlantoaxial dislocation was reduced successfully with skeletal traction. Hybrid C1-C2 fusion augmented with autogenous local bone graft with corticocancellous iliac crest bone graft was performed to avoid an unnecessary occipitocervical fusion. She was stable throughout surgery and discharged 6 days later. CT scan 6 months post-operation showed a solid posterior fusion mass. Hybrid C1-C2 fusion can be performed to avoid occipitocervical fusion despite presence of abnormal anatomy at C1 and C2 vertebrae.

Objective: The aim of this study was to compare the outcome of after-hours electively planned Posterior Spinal Fusion surgeries for Adolescent Idiopathic Scoliosis (AIS) patients with daytime surgeries., Methods: This was a retrospective propensity score-matched study using prospectively collected data. Surgeries performed between 08:00 and 16:59 h were labeled as daytime surgeries (group 1) and surgeries performed between 17:00 and 06:00 h were labeled as after-hours surgeries (group 2). The perioperative outcome parameters were average operation time in and out, operation duration, intraoperative blood loss, blood transfusion, intraoperative hemodynamic parameters, preoperative hemoglobin, postoperative hemoglobin, and total patient-controlled anesthesia (PCA) morphine usage. Radiological variables assessed were Lenke subtypes, preoperative Cobb angle, number of fusion levels, number of screws used, postoperative Cobb angle, correction rate, side bending flexibility, side bending correction index, complications rate, and length of hospitalization., Results: Average operation time in for daytime group was 11:32 ± 2:33 h versus 18:20 ± 1:05 h in after-hours group. Comparing daytime surgeries with after-hours surgeries, there were no significant differences ( p > 0.05) in the operation duration, intraoperative blood loss, intraoperative pH, bicarbonate, lactate, postoperative hemoglobin, hemoglobin drift, blood transfusion, postoperative Cobb angle, correction rate, side bending flexibility, side bending correction index, length of hospitalization, and complications rate. Total PCA morphine usage was significantly lesser in the after-hours group (18.2 ± 15.3 mg) compared with the daytime group (24.6 ± 16.6 mg; p = 0.042)., Conclusions: After-hours elective spine deformity corrective surgeries for healthy ambulatory patients with AIS were as safe as when they were done during daytime.

Purpose: To analyze the incidence, pattern, and contributing factors of pelvic obliquity among Adolescent Idiopathic Scoliosis (AIS) patients who will undergo surgery., Methods: In total, 311 patients underwent erect whole spine anteroposterior, lateral and lower limb axis films. Radiographic measurements included Transilium Pelvic Height Difference (TPHD; mm), Hip Abduction-Adduction angle (H/Abd-Add; °), Lower limb Length Discrepancy (LLD; mm), and Pelvic Hypoplasia (PH angle; °). The incidence and severity of pelvic obliquity were stratified to Lenke curve subtypes in 311 patients. The causes of pelvic obliquity were analyzed in 57 patients with TPHD ≥10 mm., Results: The mean Cobb angle was 64.0 ± 17.2°. Sixty-nine patients had a TPHD of 0 mm (22.2%). The TPHD was <5 mm in 134 (43.0%) patients, 5-9 mm in 104 (33.4%) patients, 10-14 mm in 52 (16.7%) patients, 15-19 mm in 19 (6.1%) patients, and ≥20 mm in only 2 (0.6%) patients. There was a significant difference between the Lenke curve types in terms of TPHD ( p = 0.002). L6 curve types had the highest TPHD of 9.0 ± 6.3 mm followed by L5 curves, which had a TPHD of 7.1 ± 4.8 mm. In all, 44.2% of L1 curves and 50.0% of L2 curves had positive TPHD compared to 66.7% of L5 curves and 74.1% of L6 curves which had negative TPHD. 33.3% and 24.6% of pelvic obliquity were attributed to PH and LLD, respectively, whereas 10.5% of cases were attributed to H/Abd-Add positioning., Conclusions: 76.4% of AIS cases had pelvic obliquity <10 mm; 44.2% of L1 curves and 50.0% of L2 curves had a lower right hemipelvis compared to 66.7% of L5 curves and 74.1% of L6 curves, which had a higher right hemipelvis. Among patients with pelvic obliquity ≥10 mm, 33.3% were attributed to PH, whereas 24.6% were attributed to LLD.

Study Design: Retrospective study of prospectively collected data., Objective: To analyze the incidence and the patterns of medial and lateral shoulder discordance among Lenke 1 and 2 patients., Summary of Background Data: Postoperative shoulder imbalance (PSI) is still common in Lenke 1 and 2 adolescent idiopathic scoliosis (AIS). This could be due to presence of medial dan lateral shoulder discordance., Methods: One hundred fifty-one Lenke 1 and 2 AIS patients were recruited. Lenke 1 curves were subclassified into Lenke 1-ve (flexible) (proximal thoracic side bending [PTSB] Cobb angle <15°) and 1+ve curves (stiff) (PTSB Cobb angle between 15° and 24.9°). T1 tilt represented "medial shoulder balance" and radiological shoulder height (RSH) represented "lateral shoulder balance." We categorized patients into three concordant shoulder pattern types (medial balanced/lateral balanced [MBLB], medial imbalanced+ve/lateral imbalanced+ve (MI+ve/LI+ve), medial imbalanced-ve/lateral Imbalanced-ve (MI-ve/LI-ve), and six discordant shoulder pattern types., Results: The mean age was 16.2 ± 5.7 years. Eighty-one patients (53.6%) had concordant pattern and 70 patients (46.4%) had discordant pattern. Lateral shoulder imbalance was noted in 35.1% of patients and medial shoulder imbalance in 43.7% of patients. In Lenke 1-ve curves, 35 patients (68.6%) had concordant shoulder imbalance with medial imbalanced-ve/lateral imbalanced-ve (MI-ve/LI-ve) being the commonest pattern (68.6%). In Lenke 1+ve curves, 33 patients (55.0%) had concordant shoulder pattern with medial balanced/lateral balanced (MB/LB) being the commonest type (57.6%). In Lenke 2 AIS, 27 patients (67.5%) had discordant pattern with medial imbalanced+ve/lateral balanced (MI+ve/LB) being the commonest pattern (44.4%) (P value = 0.002)., Conclusion: 46.4% Lenke 1 and 2 AIS patients had shoulder discordant pattern. This was more prevalent in Lenke 2 curves (67.5%). In Lenke 1-ve (flexible) curves, MI-ve/LI-ve pattern was the commonest pattern. In Lenke 1+ve curves (stiff), there were almost equal number of concordant and discordant shoulder pattern. In Lenke 2 patients, the most common pattern was MI+ve/LB., Level of Evidence: 4.

Study Design: Prospective study., Purpose: To compare patients' and parents' perceptions of physical attributes (PAs) of adolescent idiopathic scoliosis (AIS) patients and to report any correlations between their perceptions and Scoliosis Research Society-22r (SRS-22r) scores., Overview of Literature: Few studies have looked into the differences between patients' and parents' perceptions of their appearance., Methods: AIS patient-parent pairs (n=170) were recruited. The patients' and parents' perceptions of six PAs were evaluated: waist asymmetry (WA), rib hump (RH), shoulder asymmetry (SA), neck tilt, breast asymmetry (BrA), and chest prominence. These PAs were ranked, and an aggregate PA (Agg-PA) score was derived from a score assigned to the attribute (6 for the most important PA and 1 for the least important). The patients also completed the SRS-22r questionnaire., Results: Ninety-nine patients (58.2%) and 71 patients (41.8%) had thoracic and lumbar major curves, respectively. WA was ranked first by 54 patients (31.8%) and 50 parents (29.4%), whereas RH was ranked first by 50 patients (29.4%) and 38 parents (22.4%). The overall Agg-PA scores were similar for patients and parents (p>0.05). However, for thoracic major curves (TMCs) >40°, a significant difference was noted between the Agg-PA scores of patients and parents for SA (3.5±1.6 vs. 4.2±1.6, p=0.041) and BrA (3.0±1.6 vs. 2.2±1.3, p=0.006). For TMCs <40°, a significant difference was found between the Agg-PA scores of patients and parents for WA (3.7±1.6 vs. 4.4±1.5, p=0.050). BrA was negatively correlated with total SRS-22r score., Conclusions: There were no significant differences between patients and parents in their ranking of the most important PAs. For TMCs >40°, there were significant differences in the Agg-PA for SA and BrA. Pa¬tients were more concerned about BrA and parents were more concerned about SA. Patients' perception of the six PAs had weak correlation with SRS-22r scores.

Study Design: Retrospective study., Objective: To evaluate the perioperative outcome of dual attending surgeon strategy for severe adolescent idiopathic scoliosis (AIS) patients with Cobb angle more than or equal to 90°., Summary of Background Data: The overall complication rate for AIS remains significant and is higher in severe scoliosis. Various operative strategies had been reported for severe scoliosis. However the role of dual attending surgeon strategy in improving the perioperative outcome in severe scoliosis has not been investigated., Methods: The patients were stratified into two groups, Cobb angles 90° to 100° (Group 1) and more than 100° (Group 2). Demographic, intraoperative, preoperative, and postoperative day 2 data were collected. The main outcome measures were intraoperative blood loss, use of allogeneic blood transfusion, operative time, duration of hospital stay postsurgery, and documentation of any perioperative complications., Results: Eighty-five patients were recruited. The mean age for the whole cohort was 16.2 ± 5.2 years old. The mean age of Group 1 was 16.7 ± 5.7 and Group 2 was 15.6 ± 4.8 years old. The majority of the patients in both groups were Lenke 2 curves with the average Cobb angle of 93.9 ± 3.0° in Group 1 and 114.2 ± 10.2° in Group 2. The average operative time was 198.5 ± 47.5 minutes with an average blood loss of 1699.5 ± 939.3 mL. The allogeneic blood transfusion rate was 17.6%. The average length of stay postoperation was 71.6 ± 22.5 hours. When comparing the patients between Group 1 and Group 2, the operating time, total blood loss, allogeneic transfusion rate showed significant intergroup differences. Five complications were documented (one intraoperative seizure, one massive blood loss, one intraoperative loss of somatosensory evoked potential (SSEP) signal, and two superficial wound breakdown)., Conclusion: Dual attending surgeon strategy in severe AIS more than or equal to 90° demonstrated an average operative time of 199 minutes, intraoperative blood loss of 1.7 L, postoperative hospital stay of 71.6 hours, and a complication rate of 5.9% (5/85 patients). Curves with Cobb angle more than 100° lead to longer operating time, greater blood loss, and allogeneic transfusion rate., Level of Evidence: 4.

Study Design: A retrospective study., Objective: The aim of this study was to compare the perioperative outcome of posterior spinal fusion (PSF) between overweight (OW) adolescent idiopathic scoliosis (AIS) patients and the healthy-weight (HW) patients using propensity score matching analysis., Summary of Background Data: Obesity was found to increase postoperative surgical complications compared with the nonobese group. In scoliosis correction surgery, association of OW and perioperative risks had been explored, but most studies were retrospective in nature., Methods: From 374 patients, two comparable groups were matched using propensity score matching analysis with one-to-one nearest neighbor matching and a caliper of 0.2. There were 46 HW and OW patients in each group. The main outcome measures were intraoperative blood loss, use of allogeneic blood transfusion, operative time, duration of hospital stay post-surgery, total patient-controlled analgesia (PCA) morphine usage, perioperative complications, side bending flexibility (SBF), and correction rate (%)., Results: The mean age was 13.3 ± 1.7 and 13.2 ± 1.7 years for HW and OW groups, respectively. The majority of the patients were Lenke 1 curves; 32.6% (HW) and 26.1% (OW) with an average Cobb angle of 69.0 ± 19.1° and 68.8 ± 18.4° for each group, respectively. The two groups were comparable. The operation time was 145.2 ± 42.2 and 154.4 ± 48.3 minutes for HW and OW groups, respectively (P > 0.05). The intraoperative blood loss was almost similar in both groups; 955.1 ± 497.7 mL (HW group) and 1011.8 ± 552.7 mL (OW group) (P > 0.05). Total PCA morphine used was higher in OW group (30.4 ± 22.7 mg) than in the HW group (16.2 ± 11.3 mg). No complication was observed in HW group, while in OW group, one patient (2.2%) developed intraoperative seizure., Conclusion: OW AIS patients (≥85th percentile) had similar mean operative time, intraoperative blood loss, allogeneic transfusion rate, length of stay, and perioperative complications compared with HW AIS patients., Level of Evidence: 3.

Study Design: Case report., Objective: To describe the technical difficulties on performing posterior spinal fusion (PSF) on a pacemaker-dependent patient with complete congenital heart block and right thoracic scoliosis., Summary of Background Data: Congenital complete heart block requires pacemaker implantation at birth through thoracotomy, which can result in scoliosis. Corrective surgery in this patient was challenging. Height gain after corrective surgery may potentially cause lead dislodgement. The usage of monopolar electrocautery may interfere with the function of the implanted cardiac device., Methods: A 17-year-old boy was referred to our institution for the treatment of right thoracic scoliosis of 70°. He had underlying complete congenital heart block secondary to maternal systemic lupus erythematosus. Pacemaker was implanted through thoracotomy since birth and later changed for four times. PSF was performed by two attending surgeons with a temporary pacing inserted before the surgery. The monopolar electrocautery device was used throughout the surgery., Results: The PSF was successfully performed without any technical issues and complications. Postoperatively, his permanent pacemaker was functioning normally. Three days later, he was recovering well and was discharged home from hospital., Conclusion: This case indicates that PSF can be performed successfully with thoughtful anticipation of technical difficulties on a pacemaker-dependent patient with underlying congenital heart block., Level of Evidence: 5.

Study Design: Surgeon survey., Purpose: To study the various surgical practices of different surgeons in the Asia-Pacific region., Overview of Literature: Given the diversity among Asia-Pacific surgeons, there is no clear consensus on the preferred management strategies for cervical myelopathy. In particular, the role of prophylactic decompression for silent cervical spinal stenosis is under constant debate and should be addressed., Methods: Surgeons from the Asia-Pacific Spine Society participated in an online questionnaire comprising 50 questions. Data on clinical diagnosis, investigations and outcome measures, approach to asymptomatic and silent cervical spinal stenosis, guidelines for surgical approach, and postoperative immobilization were recorded. All parameters were analyzed by the Mantel-Haenszel test., Results: A total of 79 surgeons from 16 countries participated. Most surgeons used gait disturbance (60.5%) and dyskinetic hand movement (46.1%) for diagnosis. Up to 5.2% of surgeons would operate on asymptomatic spinal stenosis, and 18.2% would operate on silent spinal stenosis. Among those who would not operate, most (57.1%) advised patients on avoidance behavior and up to 9.5% prescribed neck collars. For ossification of the posterior longitudinal ligament (OPLL), anterior removal was most commonly performed for one-level disease (p<0.001), whereas laminoplasty was most commonly performed for two- to four-level disease (p=0.036). More surgeons considered laminectomy and fusion for multilevel OPLL. Most surgeons generally preferred to use a rigid neck collar for 6 weeks postoperatively (p<0.001)., Conclusions: The pooled recommendations include prophylactic or early decompression surgery for patients with silent cervical spinal stenosis, particularly OPLL. Anterior decompression is primarily suggested for one- or two-level disease, whereas laminoplasty is preferred for multilevel disease.

Objective: This study analyses the quantity of local bone graft obtained from different anatomical parts of the posterior elements during corrective surgery for Adolescent Idiopathic Scoliosis patients., Summary of Background Data: Locally harvested autogenous bone graft eliminates possible donor site morbidity and has all the important basic bone graft properties such as osteoinductivity, osteogenicity and osteoconductivity. Its usage was reported to be adequate to achieve fusion but none had quantifies the amount of local bone graft harvested., Methods: Total of 40 AIS patients were recruited in the study. All posterior spinal fusion surgeries were performed by the same dual surgeons and same anesthetist with a single observer collecting and measuring bone grafts harvested. The bone grafts harvested from each respective posterior element (spinous processes, laminas, facets and transverses processes) and measured accordingly., Results: There were 36 females and 4 males. Amongst cases recruited, there were 32% Lenke 1, 28% Lenke 2, 8%Lenke 3, 22%Lenke 5 and 10% Lenke 6. Total thoracic levels involved were 333, whereas lumbar levels were 81. The mean total weight of bone graft obtained per case was 36.5 ± 13.7 g. The total weight of lumbar bone graft to the number of lumbar fusion levels (4.5 ± 1.2 g/fusion level) was significantly higher than the total weight of thoracic bone graft to the number of thoracic fusion levels (3.2 ± 1.2 g/fusion level). The amount of bone graft was obtained was highest from lumbar spinous process (42%), followed by thoracic spinous process (32%), lumbar lamina (29%), lumbar facet (28%), thoracic lamina (25%), thoracic facet (22%), and thoracic transverse process (21%)., Conclusions: Lumbar vertebra provided more bone graft than thoracic vertebra. Spinous processes contributed the highest amount of local bone graft in the thoracic and lumbar spine.

Background Context: In Lenke 1C and 2C curves, the choice between selective thoracic fusion (STF) versus non-selective thoracic fusion as the optimal surgical treatment is controversial., Objective: This study aimed to assess the radiological and clinical outcome of patients with Lenke 1C and 2C curves treated with STF., Study Design: This is a retrospective study., Patient Sample: A total of 44 patients comprised the study sample., Methods: Forty-four patients with Lenke 1C and 2C curves with adolescent idiopathic scoliosis who underwent STF were reviewed. Radiological parameters and Scoliosis Research Society (SRS)-22r scores were assessed preoperatively, postoperatively, and on final follow-up. The incidence of coronal decompensation, lumbar decompensation, and adding-on phenomenon were reported., Results: Mean follow-up duration was 45.1±12.3 months and mean age was 17.0±5.1 years. The preoperative middle thoracic and thoracolumbar/lumbar (MT:TL/L) Cobb angle ratio was 1.4±0.3 and the MT:TL/L apical vertebra translation (AVT) ratio was 1.6±0.8. Final follow-up coronal balance was -13.0±11.5 mm, main thoracic AVT was 6.9±11.8 mm, and lumbar AVT was -20.4±13.8 mm (p<.05). Lumbar Cobb angle improved from 47.5°±7.8° to 24.9°±8.2° after operation and 23.3°±9.8° at final follow-up. The spontaneous lumbar curve correction rate was 50.9%. There were 9 patients (20.5%) who had coronal decompensation, 4 patients (9.1%) who had lumbar decompensation, and 11 patients (25.0%) who had adding-on phenomenon. We did not perform any revision surgery. The SRS-22r scores improved significantly in the overall scores, self-image, and mental health domain., Conclusions: Selective thoracic fusion led to improvement in the radiological and clinical outcome for patients with Lenke 1C and 2C. Although no patients required revision surgery, the rate of coronal decompensation, lumbar decompensation, and adding-on phenomenon are significant., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Study Design: Retrospective study., Objective: To investigate the association between postoperative upper instrumented vertebrae (UIV) tilt angle with postoperative medial shoulder and neck imbalance., Summary of Background Data: Studies had found that current recommendations for UIV selection were not predictive of good postoperative shoulder balance., Methods: A total of 98 patients with adolescent idiopathic scoliosis with Lenke 1/2 curves who underwent posterior spinal fusion between 2013 and 2014 with minimum follow-up of 2 years were recruited. Radiological parameters: UIV tilt angle, T1 tilt, cervical axis, and clavicle angle were measured preoperatively, postoperatively, and at final follow-up., Results: Mean age was 16.2 ± 6.2 years. Mean follow-up was 37.9 ± 6.5 months. There were 73.5% Lenke 1 and 26.5% Lenke 2 curves. Significant factors affecting postoperative T1 Tilt were postoperative UIV tilt angle, preoperative T1 tilt, and preoperative UIV tilt angle. Postoperative UIV tilt angle and preoperative cervical axis were significant factors affecting cervical axis at final follow-up. UIV level was not significant independent factor that affected postoperative T1 tilt and cervical axis. There was strong correlation between postoperative UIV tilt angle and T1 tilt for the whole cohort (P < 0.001), when UIV was at T2 (P < 0.001), T3 (P < 0.001), and T4 (P < 0.001). Postoperative UIV tilt angle also had significant correlation with cervical axis when UIV was at T2 (P = 0.021) and T3 (P = 0.009)., Conclusion: Postoperative UIV tilt angle was an independent factor, which had significant correlation with postoperative T1 tilt and cervical axis measurement. There was strong correlation between postoperative UIV tilt angle and T1 tilt for the whole cohort, when UIV was at T3 and T4. There was very strong correlation between postoperative UIV tilt angle and T1 tilt when UIV was at T2. There was also moderate and significant correlation between postoperative UIV tilt angle and cervical axis for the whole cohort., Level of Evidence: 2.

Study Design: Prospective cohort study., Purpose: This study compared cervical supine side-bending (CSSB) and cervical supine traction (CST) radiographs to assess the flexibility and predict the correctability of the proximal thoracic (PT) curve for patients with adolescent idiopathic scoliosis (AIS) classified as Lenke 1 and 2., Overview of Literature: Knowledge of the flexibility of the PT curve is crucial in the management of patients with AIS. There are no reports comparing CSSB and CST radiographs to assess this parameter., Methods: Thirty patients with Lenke 1 and 2 AIS scheduled for posterior spinal fusion surgery were recruited. A standing whole spine radiography and physician-supervised CSSB and CST radiographies were performed. Patient demographic and radiological parameters were recorded, including age, gender, weight, height, body mass index, PT angle, main thoracic angle, CSSB PT angle, CST PT angle, and postoperative PT angle. From the data collected, the curve flexibility and curve correction index were calculated and compared., Results: CSSB had a significantly (p &lt;0.05) smaller PT angle (16.6°±10.4°) in comparison to CST (23.7°±10.7°). CSSB had significantly (p &lt;0.05) greater flexibility (44.2%±19.7%) in comparison to CST (19.5%±18.1%). The CSSB correction index (1.2±0.9) was significantly closer to 1 in comparison to the CST correction index (4.4±5.3). There was no difference (p =0.72) between the CSSB PT angle (16.6°±10.4°) and the postoperative PT angle (16.1°±7.5°). However, the CST PT angle (23.7°±10.7°) was significantly (p &lt;0.05) larger than the postoperative PT angle (16.1°±7.5°)., Conclusions: CSSB radiographs were better for demonstrating PT flexibility and more accurately predicted correctability in comparison to the CST radiographs.

Thoracolumbar burst fractures are common entity in polytraumatized patients. The retropulsed burst vertebral fracture may result in spinal canal invasion with or without neurological deficit. In this situation, early surgical stabilization with decompression is vital to restore neurological function. We employed a posterior approach with a unique transpedicular reduction technique at the level of fracture for decompression and stabilisation., Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.

Background: This prospective clinical-radiological study was conducted to determine whether the dynamic mobility stress radiographs can predict the postoperative vertebral height restoration, kyphosis correction, and cement volume injected after vertebroplasty., Methods: Patients included had the diagnosis of significant back pain caused by osteoporotic vertebral compression fracture secondary to trivial injury. All the patients underwent routine preoperative sitting lateral spine radiograph, supine stress lateral spine radiograph, and supine anteroposterior spine radiograph. The radiological parameters recorded were anterior vertebral height (AVH), middle vertebral height (MVH), posterior vertebral height (PVH), MVH level below, wedge endplate angle (WEPA), and regional kyphotic angle (RKA). The supine stress versus sitting difference (SSD) for all the above parameters were calculated., Results: A total of 28 patients (4 males; 24 females) with the mean age of 75.6 ± 7.7 years were recruited into this study. The mean cement volume injected was 5.5 ± 1.8 ml. There was no difference between supine stress and postoperative radiographs for AVH ( p = 0.507), PVH ( p = 0.913) and WEPA ( p = 0.379). The MVH ( p = 0.026) and RKA ( p = 0.005) were significantly less in the supine stress radiographs compared to postoperative radiographs. There was significant correlation ( p < 0.05) between supine stress and postoperative AVH, MVH, PVH, WEPA, and RKA. The SSD for AVH, PVH, WEPA, and RKA did not have significant correlation with the cement volume ( p > 0.05). Only the SSD-MVH had significant correlation with cement volume, but the correlation was weak ( r = 0.39, p = 0.04)., Conclusions: Dynamic mobility stress radiographs can predict the postoperative vertebral height restoration and kyphosis correction after vertebroplasty for thoracolumbar osteoporotic fracture with intravertebral clefts. However, it did not reliably predict the amount of cement volume injected as it was affected by other factors.

Background: Drugs used in anesthesia can affect somatosensory evoked potential (SSEP) monitoring, which is used routinely for intraoperative monitoring of spinal cord integrity during spinal surgery., Objective: The objective of this study was to determine whether combined total intravenous anesthesia (TIVA) technique with propofol/remifentanil is associated with less SSEP suppression when compared to combined volatile agent desflurane/remifentanil anesthesia during corrective scoliosis surgery at a comparable depth of anesthesia., Design: It is a randomized controlled trial., Setting: The study was conducted at the Single tertiary University Hospital during October 2014 to June 2015., Patients: Patients who required SSEP and had no neurological deficits, and were of American Society of Anesthesiologist I and II physical status, were included. Patients who had sensory or motor deficits preoperatively and significant cardiovascular and respiratory disease were excluded. A total of 72 patients were screened, and 67 patients were randomized and allocated to two groups: 34 in desflurane/remifentanil group and 33 in TIVA group. Four patients from desflurane/remifentanil group and three from TIVA group were withdrawn due to decrease in SSEP amplitude to <0.3 µV after induction of anesthesia. Thirty patients from each group were analyzed., Interventions: Sixty-seven patients were randomized to receive TIVA or desflurane/remifentanil anesthesia., Main Outcome Measures: The measurements taken were the amplitude and latency of SSEP monitoring at five different time points during surgery: before and after the induction of anesthesia, at skin incision, at pedicle screw insertion, and at rod insertion., Results: Both anesthesia techniques, TIVA and desflurane/remifentanil, resulted in decreased amplitude and increased latencies of both cervical and cortical peaks. The desflurane/remifentanil group had a significantly greater reduction in the amplitude ( p = 0.004) and an increase in latency ( p = 0.002) of P40 compared with the TIVA group. However, there were no differences in both amplitude ( p = 0.214) and latency ( p = 0.16) in cervical SSEP between the two groups., Conclusions: Compared with TIVA technique, desflurane/remifentanil anesthesia caused more suppression in cortical SSEP, but not in cervical SSEP, at a comparable depth of anesthesia.

Purpose: To evaluate the zonal differences in risk and pattern of pedicle screw perforations in adolescent idiopathic scoliosis (AIS) patients., Methods: The scoliosis curves were divided into eight zones. CT scans were used to assess perforations: Grade 0, Grade 1(< 2 mm), Grade 2(2-4 mm) and Grade 3(> 4 mm). Anterior perforations were classified into Grade 0, Grade 1(< 4 mm), Grade 2(4-6 mm) and Grade 3(> 6 mm). Grade 2 and 3 (except lateral grade 2 and 3 perforation over thoracic vertebrae) were considered as 'critical perforations'., Results: 1986 screws in 137 patients were analyzed. The overall perforation rate was 8.4% after exclusion of the lateral perforation. The highest medial perforation rate was at the transitional proximal thoracic (PT)/main thoracic (MT) zone (6.9%), followed by concave lumbar (6.7%) and convex main thoracic (MT) zone (6.1%). The overall critical medial perforation rate was 0.9%. 33.3% occurred at convex MT and 22.2% occurred at transitional PT/MT zone. There were 39 anterior perforations (overall perforation rate of 2.0%). 43.6% occurred at transitional PT/MT zone, whereas 23.1% occurred at concave PT zone. The overall critical anterior perforation rate was 0.6%. 5/12 (41.7%) critical perforations occurred at concave PT zone, whereas four perforations occurred at the transitional PT/MT zone. There were only two symptomatic left medial grade 2 perforations (0.1%) resulting radiculopathy, occurring at the transitional main thoracic (MT)/Lumbar (L) zone., Conclusion: Overall pedicle perforation rate was 8.4%. Highest rate of critical medial perforation was at the convex MT zone and the transitional PT/MT zone, whereas highest rate of critical anterior perforation was at the concave PT zone and the transitional PT/MT zone. The rate of symptomatic perforations was 0.1%.

Background Context: Selection of upper instrumented vertebra for Lenke 5 and 6 curves remains debatable, and several authors have described different selection strategies., Objective: This study analyzed the flexibility of the unfused thoracic segments above the "potential upper instrumented vertebrae (UIV)" (T1-T12) and its compensatory ability in Lenke 5 and 6 curves using supine side bending (SSB) radiographs., Study Design: A retrospective study was used., Patient Sample: This study comprised 100 patients., Outcome Measures: The ability of the unfused thoracic segments above the potential UIV, that is, T1-T12, to compensate in Lenke 5 and 6 curves was determined. We also analyzed postoperative radiological outcome of this cohort of patients with a minimum follow-up of 12 months., Methods: Right and left SSB were obtained. Right side bending (RSB) and left side bending (LSB) angles were measured from T1 to T12. Compensatory ability of thoracic segments was defined as the ability to return to neutral (center sacral vertical line [CSVL]) with the assumption of maximal correction of lumbar curve with a horizontal UIV. The Lenke 5 curves were classified as follows: (1) Lenke 5-ve (mobile): main thoracic Cobb angle <15° and (2) Lenke 5+ve (stiff): main thoracic Cobb angle 15.0°-24.9°. This study was self-funded with no conflict of interest., Results: There were 43 Lenke 5-ve, 31 Lenke 5+ve, and 26 Lenke 6 curves analyzed. For Lenke 5-ve, >70% of thoracic segments were able to compensate when UIV were at T1-T8 and T12 and >50% at T9-T11. For Lenke 5+ve, >70% at T1-T6 and T12, 61.3% at T7, 38.7% at T8, 3.2% at T9, 6.5% at T10, and 22.6% at T11 were able to compensate. For Lenke 6 curve, >70% at T1-T6, 69.2% at T7, 19.2% at T8, 7.7% at T9, 0% at T10, 3.8% at T11, and 34.6% at T12 were able to compensate. There was a significant difference between Lenke 5-ve versus Lenke 5+ve and Lenke 5-ve versus Lenke 6 from T8 to T11. There were no significance differences between Lenke 5+ve and Lenke 6 curves from T1 to T11., Conclusions: The compensatory ability of the unfused thoracic segment of Lenke 5+ve curves was different from the Lenke 5-ve curves, and it demonstrated characteristics similar to the Lenke 6 curves., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Study Design: A prospective cohort study., Objective: The aim of this study was to determine the feasibility of an accelerated recovery protocol for Asian adolescent idiopathic scoliosis (AIS) patients undergoing posterior spinal fusion (PSF)., Summary of Background Data: There has been successful implementation of an accelerated recovery protocol for AIS patients undergoing PSF in the western population. No similar studies have been reported in the Asian population., Methods: Seventy-four AIS (65 F, 9 M) patients scheduled for PSF surgery were recruited. The accelerated protocol encompasses preoperative regime, preoperative day of surgery counseling, intraoperative strategies, an accelerated postoperative rehabilitation and pain management regime. All patients were operated using a dual attending surgeon strategy. Outcome measures included pain scores at five time intervals, length of stay, and detailed recovery milestones. Any complications or readmissions during the first 4 months postoperative period were recorded., Results: Mean duration of operation was 2.2 ± 0.3 hours with a mean blood loss of 824.3 ± 418.2 mL. No patients received allogenic blood transfusion. The mean length of stay was 3.6 ± 0.6 days. Surgical wound pain score was 6.4 ± 2.1 at 12 hours, which reduced to 5.0 ± 2.0 at 60 hours. Abdominal pain peaked at 36 hours with pain scores 2.4 ± 2.9. First liquid intake was at 5.2 ± 7.5 hours, urinary catheter removal at 18.7 ± 4.8 hours, sitting up at 20.6 ± 9.1 hours, ambulation at 27.2 ± 0.5 hours, consumption of solid food at 32.2 ± 0.5 hours, first flatus at 39.0 ± 0.7 hours, and first bowel movement at 122.1 ± 2.0 hours. The complication rate was 1.4% due to superficial wound infection with one patient failed to comply with the accelerated protocol., Conclusion: An accelerated recovery protocol following PSF for AIS is feasible without increasing the complication or readmission rates. The total length of stay was 3.6 days and this is comparable with the outcome in western population., Level of Evidence: 4.

To review existing publications on the safety of pedicle screw insertions in adolescent idiopathic scoliosis (AIS). Despite having increased risk for neurological and visceral injuries, the use of pedicle screws have led to increased correction rates in scoliosis surgery. A review was performed on topics pertinent to pedicle screw insertion in AIS, which included pedicle morphometry in AIS, structures at risk during pedicle screw insertion, and accuracy and safety of various pedicle screw insertion techniques. The importance of computer navigation and future research regarding pedicle screw placement in AIS were also briefly reviewed. Many authors have reported abnormal pedicle anatomy in AIS. Injury to the neural structures was highest over the apical region, whereas aortic injury was the highest at T5 and T10. In the proximal thoracic spine, the esophagus could be injured even with screws as short as 25 mm. Overall pedicle perforation rates for perforations >0 and >2 mm (assessed by computed tomography) ranged from 6.4% to 65.0% and 3.7% to 29.9%, respectively. The critical pedicle perforation (>2 mm excluding lateral thoracic) and anterior perforation (>0 mm) rates was reported to range from 1.5% to 14.5% and 0.0% to 16.1%, respectively. Pedicle perforation rates were lower with the use of computer navigation. The incidence of neurological adverse events after scoliosis surgery was 0.06%-1.9%. Aortic injury has only been observed in case reports. According to the available literature, pedicle screw insertion in AIS is considered safe with low rates of clinical adverse events. Moreover, the use of navigation technology has been shown to reduce pedicle perforation rates., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported.

Purpose: This study aimed at studying the accuracy and safety of extra-pedicular screw insertion for dysplastic pedicles in AIS comparing cannulated screw system versus conventional screw system., Methods: 104 AIS patients with 1524 pedicle screws were evaluated using CT scan. 302 screws were inserted in dysplastic pedicles using fluoroscopic guidance technique. 155 screws were inserted using a cannulated system (Group 1), whereas 147 screws were inserted using standard screws (Group 2). The pedicle perforations were assessed using a classification by Rao et al.; G0: no violation; G1: <2 mm perforation; G2: 2-4 mm perforation; and G3: >4 mm perforation). For anterior perforations, the pedicle perforations were assessed using a modified grading system (Grade 0: no violation, Grade 1: less than 4 mm perforation; Grade 2: 4 mm to 6 mm perforation; and Grade 3: more than 6 mm perforation)., Results: The perforation rate in Group 1 was 4.5% and in Group 2 was 15.6% (p = 0.001). Most of the perforations were anterior perforations (53.3%). The anterior perforation rate in Group 1 was 1.9% compared to 8.8% in Group 2 (p = 0.009). Group 1 has a medial perforation rate of 1.3% compared to Group 2, 6.1% (p = 0.031). The rate of critical pedicle perforation in Group 1 was 2.6% and in Group 2 was 6.8% (p = 0.102). In Group 1, there were no critical medial perforation but there was one G2 lateral perforation, one G2 superior perforation and two G3 anterior perforations. In Group 2, there were three G2 medial perforations, one G2 lateral perforation, one G2 anterior perforation and five G3 anterior perforations., Conclusion: Usage of cannulated screw system significantly increases the accuracy of pedicle screw insertion in dysplastic pedicles in AIS.

Study Design: Randomized controlled trial., Objective: The present study investigated the effectiveness of chewing gum on promoting faster bowel function and its ability to hasten recovery for patients with adolescent idiopathic scoliosis (AIS) after posterior spinal fusion (PSF) surgery., Summary of Background Data: Sham feeding with chewing gum had been reported to reduce the incidence of postoperative ileus by accelerating recovery of bowel function., Methods: We prospectively recruited and randomized 60 patients with AIS scheduled for PSF surgery into treatment (chewing gum) and control group. The patient-controlled anesthesia usage, wound pain score, abdominal pain score, nausea score, and abdominal girth were assessed and recorded at 12, 24, 36, 48, and 60 hours postoperatively. The timing for the first fluid intake, first oral intake, sitting up, walking, first flatus after surgery, first bowel opening after surgery, and duration of hospital stay were also assessed and recorded., Results: We found that there were no significant differences (P > 0.05) in patient-controlled anesthesia usage, wound pain score, abdominal pain score, nausea score, and abdominal girth between treatment (chewing gum) and control groups. We also found that there were no significant difference (P > 0.05) in postoperative recovery parameters, which were the first fluid intake, first oral intake, sitting up after surgery, walking after surgery, first flatus after surgery, first bowel opening after surgery, and duration of hospital stay between both groups. The wound pain was the worst at 12 hours postoperatively, which progressively improved in both groups. The abdominal pain progressively worsened to the highest score at 48 hours in the treatment group and 36 hours in the control group before improving after that. The pattern of severity and recovery of wound pain and abdominal pain was different., Conclusion: We found that chewing gum did not significantly reduce the abdominal pain, promote faster bowel function, or hasten patient recovery., Level of Evidence: 1.

Study Design: A prospective cohort study., Objective: The aim of this study was to determine and evaluate the trajectory of surgical wound pain from day 1 to day 14 after posterior spinal fusion (PSF) surgery in patients with adolescent idiopathic scoliosis (AIS)., Summary of Background Data: Information regarding how the postoperative pain improves with time offers invaluable information not only to the patients and parents but also to assist the clinician in managing postoperative pain., Methods: AIS patients who were planned for elective PSF surgery from September 2015 to December 2015 were prospectively recruited into this study. All patients underwent a similar pain management regimen with patient-controlled anesthesia (PCA) morphine, acetaminophen, celecoxib, and oxycodone hydrochloride., Results: A total of 40 patients (36 F:4 M) were recruited. The visual analogue score (VAS) pain score was highest at 12 hours postoperation (6.0 ± 2.3). It reduced to 3.9 ± 2.2 (day 4), 1.9 ± 1.6 (day 7), and 0.7 ± 1.1 (day 14). The total PCA usage in all patients was 12.4 ± 9.9 mg (first 12 hours), 7.1 ± 8.0 mg (12 to 24 hours), 5.6 ± 6.9 (24-36 hours), and 2.1 ± 6.1 mg (36-48 hours). The celecoxib capsules usage was reducing from 215.0 ± 152.8 mg at 24 hours to 55.0 ± 90.4 mg on day 14. The acetaminophen usage was reducing from 2275 ± 1198 mg at 24 hours to 150 ± 483 mg at day 14. Oxycodone hydrochloride capsules consumption rose to the peak of 1.4 ± 2.8 mg on day 4 before gradually reducing to none by day 13., Conclusion: With an adequate postoperation pain regimen, significant pain should subside to a tolerable level by postoperative day 4 and negligible by postoperative day 7. Patient usually can be discharged on postoperative day 4 when the usage of PCA morphine was not required., Level of Evidence: 2.

Study Design: Prospective propensity score-matched study., Objective: To compare the outcomes of minimal invasive surgery (MIS) and conventional open surgery for spinal metastasis patients., Summary of Background Data: There is lack of knowledge on whether MIS is comparable to conventional open surgery in treating spinal metastasis., Methods: Patients with spinal metastasis requiring surgery from January 2008 to December 2010 in two spine centers were recruited. The demographic, preoperative, operative, perioperative and postoperative data were collected and analyzed. Thirty MIS patients were matched with 30 open surgery patients using propensity score matching technique with a match tolerance of 0.02 based on the covariate age, tumor type, Tokuhashi score, and Tomita score., Results: Both groups had significant improvements in Eastern Cooperative Oncology Group (ECOG), Karnofsky scores, visual analogue scale (VAS) for pain and neurological status postoperatively. However, the difference comparing the MIS and open surgery group was not statistically significant. MIS group had significantly longer instrumented segments (5.5 ± 3.1) compared with open group (3.8 ± 1.7). Open group had significantly longer decompressed segment (1.8 ± 0.8) than MIS group (1.0 ± 1.0). Open group had significantly more blood loss (2062.1 ± 1148.0 mL) compared with MIS group (1156.0 ± 572.3 mL). More patients in the open group (76.7%) needed blood transfusions (with higher average units of blood transfused) compared with MIS group (40.0%). Fluoroscopy time was significantly longer in MIS group (116.1 ± 63.3 s) compared with open group (69.9 ± 42.6 s). Open group required longer hospitalization (21.1 ± 10.8 days) compared with MIS group (11.0 ± 5.0 days)., Conclusion: This study demonstrated that MIS resulted in comparable outcome to open surgery for patients with spinal metastasis but has the advantage of less blood loss, blood transfusions, and shorter hospital stay., Level of Evidence: 3.

Background: Massive blood loss during posterior spinal fusion for adolescent idiopathic scoliosis remains a significant risk for patients. There is no consensus on the benefit of acute normovolemic hemodilution (ANH) or intraoperative cell salvage (ICS) in scoliosis surgery., Methods: Patients were randomized to one of two groups. Group A received ANH and ICS during operation, while group B received only ICS. Patients' age, sex, height, weight, body blood volume, number of fusion level, Cobb angle, number of screws, duration of surgery, and skin incision length were recorded. Hemoglobin and hematocrit levels were obtained preoperatively and postoperatively (0 h and 24 h)., Results: There were 22 patients in each group. There was no significant difference in total blood loss. The perioperative decrease in hemoglobin levels between preoperation and postoperation 24 h (group A 2.79 ± 1.15 and group B 2.76 ± 1.00) showed no significant difference ( p = 0.93). Group A observed a larger decrease in hemoglobin levels at postoperative 0 h relative to preoperative level (2.57 ± 0.82 g/dl), followed by a smaller decrease within the next 24 h (0.22 ± 1.33 g/dl). Group B showed a continued drop in hemoglobin levels of similar magnitude at postoperation 0 h (1.60 ± 0.67 g/dl) and within the next 24 h (1.16 ± 0.78 g/dl). One patient from group B received 1 unit of allogenic blood transfusion ( p = 0.33)., Conclusions: The addition of ANH to ICS in posterior spinal fusion surgery for AIS resulted in a similar decrease in hemoglobin levels between preoperative values and at 24 h postoperatively.

Purpose: This study investigates the safety and accuracy of percutaneous pedicle screws placed using fluoroscopic guidance in the thoracolumbosacral spine among Asian patients., Methods: Computerized tomography scans of 128 patients who had surgery using fluoroscopic-guided percutaneous pedicle screws were selected. Medial, lateral, superior, and inferior screw perforations were classified into grade 0 (no violation), grade 1 (<2 mm perforation), grade 2 (2-4 mm perforation), and grade 3(>4 mm perforation). Anterior perforations were classified into grade 0 (no violation), grade 1 (<4 mm perforation), grade 2 (4-6 mm perforation), and grade 3(>6 mm perforation). Grade 2 and grade 3 perforation were considered as "critical" perforation., Results: In total, 1002 percutaneous pedicle screws from 128 patients were analyzed. The mean age was 52.7 ± 16.6. There were 70 male patients and 58 female patients. The total perforation rate was 11.3% (113) with 8.4% (84) grade 1, 2.6% (26) grade 2, and 0.3% (3) grade 3 perforations. The overall "critical" perforation rate was 2.9% (29 screws) and no complications were noted. The highest perforation rates were at T4 (21.6%), T2 (19.4%), and T6 (19.2%)., Conclusion: The total perforation rate of 11.3% with the total "critical" perforation rate of 2.9% (2.6% grade 2 and 0.3% grade 3 perforations). The highest perforation rates were found over the upper to mid-thoracic region. Fluoroscopic-guided percutaneous pedicle screws insertion among Asians has the safety and accuracy comparable to the current reported percutaneous pedicle screws and open pedicle screws techniques.

Purpose: This study analysed the accuracy and safety of the fluoroscopic guided percutaneous screws in the upper thoracic vertebrae (T1-T6)., Methods: Computed tomography scans from 74 patients were retrospectively evaluated between January 2008 and December 2012. Pedicle perforations were classified by two types of grading systems. For medial, lateral, superior and inferior perforations: grade 0 - no violation; grade 1 - <2 mm; grade 2 - 2-4 mm and grade 3 - >4 mm. For anterior perforations: grade 0 - no violation; grade 1 - <4 mm; grade 2 - 4-6 mm and grade 3 - >6 mm., Results: There were 35 (47.3%) male and 39 (52.7%) female patients with a total 260 thoracic pedicle screws (T1-T6) analysed. There were 32 screw perforations which account to a perforation rate of 12.3% (11.2% grade 1, 0.7% grade 2 and 0.4% grade 3). None led to pedicle screw-related complications. The perforation rate was highest at T1 (33.3%, all grade 1 perforations), followed by T6 (14.5%) and T4 (14.0%)., Conclusion: Fluoroscopic guided percutaneous pedicle screws of the upper thoracic spine (T1-T6) are technically more demanding and carry potential risks of serious complications. Extra precautions need to be taken when fluoroscopic guided percutaneous pedicle screws are placed at T1 and T2 levels, due to high medial pedicular angulation and obstruction of lateral fluoroscopic images by the shoulder girdle and at T4-T6 levels, due to smaller pedicular width.

Study Design: Clinical imaging study., Purpose: To study the surgical morphometry of C1 and C2 vertebrae in Chinese, Indian, and Malay patients., Overview of Literature: C1 lateral mass and C2 pedicle screw fixation is gaining popularity. However, there is a lack of C1-C2 morphometric data for the Asian population., Methods: Computed tomography analysis of 180 subjects (60 subjects each belonging to Chinese, Indian, and Malay populations) using simulation software was performed. Length and angulations of C1 lateral mass (C1LM) and C2 pedicle (C2P) screws were assessed., Results: The predicted C1LM screw length was between 23.2 and 30.2 mm. The safe zone of trajectories was within 11.0°±7.7° laterally to 29.1°±6.2° medially in the axial plane and 37.0°±10.2° caudally to 20.9°±7.8° cephalically in the sagittal plane. The shortest and longest predicted C2P screw lengths were 22.1±2.8 mm and 28.5±3.2 mm, respectively. The safe trajectories were from 25.1° to 39.3° medially in the axial plane and 32.3° to 45.9° cephalically in the sagittal plane., Conclusions: C1LM screw length was 23-30 mm with the axial safe zone from 11° laterally to 29° medially and sagittal safe zone at 21° cephalically. C2P screw length was 22-28 mm with axial safe zone from 26° to 40° medially and sagittal safe zone from 32° to 46° cephalically. These data serve as an important reference for Chinese, Indian, and Malay populations during C1-C2 instrumentation., Competing Interests: Conflict of Interest: No potential conflict of interest relevant to this article was reported.

Study Design: Cadaveric and biomechanical study., Objective: The aim of this study was to assess the safety and pullout strength of medial, partial nonthreaded thoracic pedicle screws compared with conventional screws., Summary of Background Data: The perforation rate of the pedicle screws has been reported as high as 41%. Nerve injury and irritation can result from the compression of malpositioned screw on neural structures., Methods: Ten fresh cadavers were studied. Screws, 5.0 and 6.0 mm, were inserted from T1 to T6 and T7 to T12, respectively. Pedicle perforations and fractures were recorded upon screw insertion and final positioning (nonthreaded portion facing medially) after a wide laminectomy. Pullout strength of novel and conventional screws were then tested using an Instron machine in an artificial bone substitute., Results: A total of 240 thoracic pedicle screws were inserted. Of them, 88.8% (213 screws) were fully contained during screw insertion. There were 5.0% (12 screws) grade 1 medial perforations and 6.2% (15 screws) grade 1 lateral perforations during screw insertion. Upon final positioning, 93.8% (225 screws) were fully contained. All grade 1 medial perforations, which occurred during insertion, were converted to grade 0. No dural or nerve root injuries occurred. Pedicle split fractures were noted in 6.7% (16 screws). The use of medial, partial nonthreaded screws reduced the overall perforation rate from 11.2% to 6.2%. The mean pullout load for the 5 mm fully threaded screw versus medial, partial nonthreaded was 1419.3±106.1 N (1275.8-1538.8 N) and 1336.6±44.2 N (1293.0-1405.1 N) respectively, whereas 6 mm pullout load averaged 2126.0±134.8 N (1986.3-2338.3 N) and 2036.5±210.0 N (1818.4-2355.9 N). The difference was not statistically significant., Conclusions: The use of medial, partial nonthreaded pedicle screws reduced the medial perforation rate from 5.0% to 0%; however, the pullout strength was not significantly reduced. The use of this novel screw can potentially reduce the incidence of nerve injury or irritation after medial pedicle perforations.

The prevalence of neuropathic low back pain differs in different ethnic populations. The aims of the study are to determine its frequency and associations in a multi-ethnic cohort of Asian low back pain patients. This was a cross-sectional study of low back patients seen at the University of Malaya Medical Centre, Kuala Lumpur, Malaysia. Neuropathic low back pain patients were identified using the painDETECT questionnaire and compared with non-neuropathic (unclear or nociceptive) low back pain patients, in terms of socio-demographic and clinical factors, pain severity (numerical pain rating scale, NPRS), disability (Roland Morris Disability Questionnaire, RMDQ), as well as anxiety and depression (Hospital Anxiety and Depression Scale, HADS). Of 210 patients, 26 (12.4%) have neuropathic low back pain. Neuropathic pain is associated with non-Chinese ethnicity, higher body mass index and pain radiation below the knee. Patients with neuropathic pain have significantly higher NPRS and RMDQ scores, and there are more subjects with anxiety on HADS. However, there are no differences between the groups in age, gender, pain duration or underlying diagnosis of low back pain. The prevalence of neuropathic low back pain in a multi-ethnic Malaysian cohort is lower than previously reported in other populations with possible differences between ethnic groups. It is associated with greater pain severity, disability and anxiety.

Background Context: The clinical application of recombinant bone morphogenetic protein in spinal surgery has been shown to be safe and effective. However, its use in minimally invasive spine surgery has been limited to anterior interbody fusion procedures. To date, no study has evaluated the feasibility of percutaneous posterolateral fusion in the spine utilizing recombinant bone morphogenetic protein-2 (rhBMP-2)., Purpose: To evaluate the feasibility of percutaneous posterolateral fusion in the spine utilizing rhBMP-2., Study Design: Animal study., Methods: This is an animal research model involving 32 New Zealand white rabbits stratified into 4 study groups: control, autogenous iliac crest bone graft (ICBG), demineralized bone matrix (DBM), and rhBMP-2 groups, with 8 study subjects per group. The rhBMP-2 group was subdivided into the open technique (right side) and the percutaneous technique groups (left side). Fusion was graded at 6 weeks and 3 months after plain radiography, computed tomography, and clinical assessment with the following grading system: grade A, no bone formation; grade B, non-bridging bone formation; grade C, fusion; and grade D, fusion with ectopic bone formation., Results: No fusion was noted in the placebo and the DBM groups. However, in the DBM group, bone formation occurred in 37.5% of the subjects. The rhBMP-2 group had a higher fusion rate compared with the ICBG group at 6 weeks and 3 months. The fusion rate for the ICBG, the rhBMP-2 (open), and the rhBMP-2 (percutaneous) groups were 37.5%, 87.5%, and 50.0% at 6 weeks and 50.0%, 100.0%, and 62.5% at 3 months, respectively. Ectopic bone formation occurred in 12.5% of the cases in the rhBMP-2 (percutaneous) group and in 25.0% of the cases in the rhBMP-2 (open) group., Conclusions: Usage of rhBMP-2 is feasible for percutaneous posterolateral fusion of the lumbar spine in this animal model. However, a more precise delivery system might improve the fusion rate when the percutaneous technique is used. A significant rate of ectopic bone formation occurred when rhBMP-2 was used.