METHODS: This study involved 70 consecutive Lenke 1 and 2 AIS patients who underwent scoliosis correction with alternate-level pedicle screw instrumentation. Preoperative parameters that were measured included main thoracic (MT) Cobb angle, proximal thoracic (PT) Cobb angle, lumbar Cobb angle as well as thoracic kyphosis. Side-bending flexibility (SBF) and fulcrum-bending flexibility (FBF) were derived from the measurements. Preoperative height and post-operative height increment was measured by an independent observer using a standardized method.

RESULTS: MT Cobb angle and FB Cobb angle were significant predictors ( p < 0.001) of height increment from multiple linear regression analysis ( R = 0.784, R2 = 0.615). PT Cobb angle, lumbar, SB Cobb angle, preoperative height and number of fused segment were not significant predictors for the height increment based on the multivariable analysis. Increase in post-operative height could be calculated by the formula: Increase in height (cm) = (0.09 × preoperative MT Cobb angle) - (0.04 x FB Cobb angle) - 0.5.

OBJECTIVE: To investigate the accuracy and safety of pedicle screws placed in adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA: The reported pedicle screws perforation rates for corrective AIS surgery vary widely from 1.2% to 65.0%. Knowledge regarding the safety of pedicle screws in scoliosis surgery is very important in preventing complications.

METHODS: This study investigates the accuracy and safety of pedicle screws placed in 140 AIS patients. CT scans were used to assess the perforations that were classified according to Rao et al (2002): 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 (excluding lateral grade 2 and 3 perforation over thoracic vertebrae) were considered as critical perforations.

RESULTS: A total of 2020 pedicle screws from 140 patients were analyzed. The overall total perforation rate was 20.3% (410 screws) with 8.2% (166 screws) grade 1, 2.9% (58 screws) grade 2 and 9.2% (186 screws) grade 3 perforations. Majority of the perforations was because of lateral perforation occurring over the thoracic region, as a result of application of extrapedicular screws at this region. When the lateral perforations of the thoracic region were excluded, the perforation rate was 6.4% (129 screws), grade 2, 1.4% (28 screws) and grade 3, 0.8% (16 screws). There were only two symptomatic left medial grade 2 perforations: one screw at T12 presented with postoperative iliac crest numbness and another screw at L2 presented with radicular pain that subsided with conservative treatment. There were six anterior perforations abutting the right lung, four anterior perforations abutting the aorta, two anterior perforations abutting the esophagus, and one abutting the trachea was noted.

CONCLUSION: Pedicle screws insertion in AIS has a total perforation rate of 20.3%. After exclusion of lateral thoracic perforations, the overall perforation rate was 8.6% with a critical perforation rate of 2.2% (44/2020). The rate of symptomatic screw perforation leading to radicular symptoms was 0.1%. There was no spinal cord, aortic, esophageal, or lung injuries caused by malpositioned screws in this study.

OBJECTIVE: To determine if surgically leveling the upper thoracic spine in patients with adolescent idiopathic scoliosis results in level shoulders postoperatively.

SUMMARY OF BACKGROUND DATA: Research has shown that preoperatively tilted proximal ribs and T1 tilt are more correlated with trapezial prominence than with clavicle angle.

METHODS: Prospectively collected Lenke 1 and 2 cases from a single center were reviewed. Clinical shoulder imbalance was measured from 2-year postoperative clinical photos. Lateral shoulder imbalance was assessed utilizing clavicle angle. Medial imbalance was assessed with trapezial angle (TA), and trapezial area ratio (TAR). First rib angle, T1 tilt, and upper thoracic curve were measured from 2-year radiographs. Angular measurements were considered level if ≤ 3° of zero. TAR was considered level if ≤ 1 standard deviation of the natural log of the ratio. Upper thoracic Cobb at 2-years was categorized as at or below the mean value (≤ 14°) versus above the mean.

OBJECTIVE: To analyze the amount of blood loss at different stages of Posterior Instrumented Spinal Fusion (PSF) surgery in adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA: Knowing the pattern of blood loss at different surgical stages may enable the surgical team to formulate a management strategy to reduce intraoperative blood loss.

METHODS: One hundred AIS patients who underwent PSF from January 2013 to December 2014 were recruited. The operation was divided into six stages; stage 1-exposure, stage 2-screw insertion, stage 3-release, stage 4-correction, stage 5-corticotomies and bone grafting, and stage 6-closure. The duration and blood loss at each stage was documented. The following values were calculated: total blood loss, blood loss per estimated blood volume, blood loss per minute, blood loss per vertebral level fused, and blood loss per minute per vertebral level fused.

RESULTS: There were 89 females and 11 males. The mean age was 17.0 ± 5.8 years old. Majority (50.0%) were Lenke 1 curve type. The mean preoperative major Cobb angle was 64.9 ± 15.0°. The mean number of levels fused was 9.5 ± 2.3 levels. The mean operating time was 188.5 ± 53.4 minutes with a mean total blood loss 951.0 ± 454.0 mLs. The highest mean blood loss occurred at stage 2 (301.0 ± 196.7 mL), followed by stage 4 (226.8 ± 171.2 mL) and stage 5 (161.5 ± 146.6 mL). The highest mean blood loss per minute was at stage 5 (17.1 ± 18.3 mL/min), followed by stage 3 (12.0 ± 10.8 mL/min). The highest mean blood loss per vertebral levels fused was at stage 2 (31.0 ± 17.7 mL/level), followed by stage 4 (23.9 ± 18.1 mL/level) and stage 5 (16.6 ± 13.3 mL/level).

CONCLUSION: All stages were significant contributors to the total blood loss except exposure (stage 1) and closure (stage 6). Blood loss per minute and blood loss per minute per level was highest during corticotomies (stage 5), followed by release (stage 3). However, the largest amount of total blood loss occurred during screw insertion (stage 2).

METHODS: Case report.

RESULTS: The use pre-operative halo-ring traction for a duration of 6 weeks in this case lead to improvement in cobb angle from 123.3°, kyphotic angle 87.1° to cobb angle of 78.0°, kyphotic angle 57.2° (on bending and stress films). The operation was completed in 150 min, blood loss 1050 ml (25 ml/kg), and cell salvage of 490 ml. He was immediately extubated post correction, but monitored in ICU for a day. Total length of stay was 8 days without any perioperative morbidity or allogeneic blood transfusion. Final post-operative radiograph showed a cobb angle of 44.2°, kyphotic angle 22.8°. Follow up at 27 months showed solid union with no significant loss of correction.

OBJECTIVE: To evaluate the perioperative outcome of posterior spinal fusion in adolescent idiopathic scoliosis (AIS) patients comparing a single attending surgeon strategy (G1) versus a dual attending surgeon strategy (G2).

SUMMARY OF BACKGROUND DATA: The complication rate for surgical correction in AIS is significant. There are no prospective studies that investigate dual attending surgeon strategy for posterior spinal fusion in AIS.

METHODS: A total of 60 patients (30 patients in each arm) were recruited. The patients were comparable for age, gender, Lenke classification, major Cobb angle magnitude, and number of fusion levels. The anesthetic, surgical, and postoperative protocol was standardized. The outcome measures included the operative duration, blood loss, postoperative hemoglobin, need for transfusion, morphine usage, duration of hospital stay, intraoperative lactate levels, and pH. The timing of the operation at six critical stages of the operation was recorded.

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.

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.

OBJECTIVE: To determine the parents'/patients' perception on the informed consent process prior to posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS) patients.

SUMMARY OF BACKGROUND DATA: Understanding parents/patients perspective on the process is important in order to achieve the goal of consent and prevent medico-legal implications.

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.

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).