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.
RESULTS: The mean operative time for G2 was 173.6 ± 27.0 minutes versus 248.0 ± 49.9 minutes in G1 (P
METHODS: The scoliosis curves were divided into eight zones. CT scans were used to assess perforations: Grade 0, Grade 1( 4 mm). Anterior perforations were classified into Grade 0, Grade 1( 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%.
OBJECTIVE: The aim of this study was to analyze the proximal thoracic (PT) flexibility and its compensatory ability above the "potential UIV."
SUMMARY OF BACKGROUND DATA: Shoulder and neck imbalance can be caused by overcorrection of the main thoracic (MT) curve due to inability of PT segment to compensate.
METHODS: Cervical supine side bending (CSB) radiographs of 100 Lenke 1 and 2 patients were studied. We further stratified Lenke 1 curves into Lenke 1-ve: PT side bending (PTSB) 80.0% of cases of the PT segment were unable to compensate at T3-T6. In Lenke 1+ve curves, 78.4% were unable to compensate at T6, followed by T5 (75.7%), T4 (73.0%), T3 (59.5%), T2 (27.0%), and T1 (21.6%). In Lenke 1-ve curves, 36.4% of cases were unable to compensate at T6, followed by T5 (45.5%), T4 (45.5%), T3 (30.3%), T2 (21.2%), and T1 (15.2%). A significant difference between Lenke 1-ve and Lenke 1+ve was observed from T3 to T6. The difference between Lenke 1+ve and Lenke 2 curves was significant only at T2.
CONCLUSION: The compensation ability and the flexibility of the PT segments of Lenke 1-ve and Lenke 1+ve curves were different. Lenke 1+ve curves demonstrated similar characteristics to Lenke 2 curves.
LEVEL OF EVIDENCE: 3.
OBJECTIVE: To report the successful rehabilitation and the training progress of an elite high performance martial art exponent after selective thoracic fusion for Adolescent Idiopathic Scoliosis (AIS).
SUMMARY OF BACKGROUND DATA: Posterior spinal fusion for AIS will result in loss of spinal flexibility. The process of rehabilitation after posterior spinal fusion for AIS remains controversial and there are few reports of return to elite sports performance after posterior spinal fusion for AIS.
METHODS: We report a case of a 25-year-old lady who was a national Wu Shu exponent. She was a Taolu (Exhibition) exponent. She underwent Selective Thoracic Fusion (T4 to T12) using alternate level pedicle screw placement augmented with autogenous local bone graft in June 2014. She commenced her training at 3-month postsurgery and the intensity of her training was increased after 6 months postsurgery. We followed her up to 2 years postsurgery and showed no instrumentation failure or lost of correction.
RESULTS: After selective thoracic fusion, her training process consisted of mainly speed training, core strengthening, limb strengthening, and flexibility exercises. At 17 months of postoperation, she participated in 13th World Wu Shu Championship 2015 and won the silver medal.
CONCLUSION: Return to elite high-performance martial arts sports was possible after selective thoracic fusion for AIS. The accelerated and intensive training regime did not lead to any instrumentation failure and complications.
LEVEL OF EVIDENCE: 2.
METHODS: Three-dimensional computed tomographies of 180 subjects (60 from each ethnic) were analyzed. The length and angulations of C1LM screw and the location of internal carotid artery (ICA) in relation to C1LM were assessed and classified according to the classification by Murakami et al. The incidence of ponticulus posticus (PP) was determined and the differences among the population of these three ethnics were recorded.
RESULTS: The average base length was 8.5 ± 1.4 mm. The lengths within the lateral mass were between 14.7 ± 1.6 mm and 21.7 ± 2.3 mm. The prevalence of PP was 8.3%. 55.3% (199) of ICA were located in zone 0, 38.3% (138) in zone 1-1, 6.4% (23) in zone 1-2, and none in zone 1-3 and zone 2. The average angulation from the entry point to the ICA was 8.5° ± 6.4° laterally. The mean distance of ICA from C1 anterior cortex was 3.7 ± 1.7 mm (range: 0.6∼11.3). There was no difference in distribution of ICA in zone 1 among the three population (Chinese-47%, Indians-61%, and Malays-53%; p > 0.05).
CONCLUSIONS: No ICA is located medial to the entry point of C1LM screw. If bicortical purchase of C1LM screw is needed, screw protrusion of less than 3 mm or medially angulated is safe for ICA. The incidence of PP is 8.3% with higher prevalence among the Indian population.
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.
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 <0.05) smaller PT angle (16.6°±10.4°) in comparison to CST (23.7°±10.7°). CSSB had significantly (p <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 <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.
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.
Material and Methods: Twenty-one patients with AS and DISH who were surgically treated between 2009 and 2017 were recruited. Outcomes of interest included operative time, intra-operative blood loss, complications, duration of hospital stay and fracture union rate.
Results: Mean age was 69.2 ± 9.9 years. Seven patients had AS and 14 patients had DISH. 17 patients sustained AO type B3 fracture and 4 patients had type B1 fracture. Spinal trauma among these patients mostly involved thoracic spine (61.9%), followed by lumbar (28.6%) and cervical spine (9.5%). MISt using PPS was performed in 14 patients (66.7%) whereas open surgery in 7 patients (33.3%). Mean number of instrumentation level was 7.9 ± 1.6. Mean operative time in MISt and open group was 179.3 ± 42.3 minutes and 253.6 ± 98.7 minutes, respectively (p=0.028). Mean intra-operative blood loss in MISt and open group was 185.7 ± 86.4ml and 885.7 ± 338.8ml, respectively (p<0.001). Complications and union rate were comparable between both groups.
Conclusion: MISt using PPS lowers the operative time and reduces intra-operative blood loss in vertebral fractures in ankylosed disorders. However, it does not reduce the perioperative complication rate due to the premorbid status of the patients. There was no significant difference in the union rate between MISt and open surgery.
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.
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.
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.