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  1. Chiu CK, Chan CY, Aziz I, Hasan MS, Kwan MK
    Spine (Phila Pa 1976), 2016 May;41(9):E566-73.
    PMID: 26630421 DOI: 10.1097/BRS.0000000000001304
    STUDY DESIGN: Prospective clinical study.

    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).

    LEVEL OF EVIDENCE: 2.

    Matched MeSH terms: Spinal Fusion/adverse effects*
  2. Kwan MK, Chiu CK, Tan PH, Chian XH, Ler XY, Ng YH, et al.
    Spine J, 2018 12;18(12):2239-2246.
    PMID: 29733900 DOI: 10.1016/j.spinee.2018.05.007
    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 (pfusion 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.

    Matched MeSH terms: Spinal Fusion/adverse effects*
  3. Kwan MK, Chiu CK, Chan TS, Abd Gani SM, Tan SH, Chan CYW
    Spine J, 2018 01;18(1):53-62.
    PMID: 28751241 DOI: 10.1016/j.spinee.2017.06.020
    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.

    Matched MeSH terms: Spinal Fusion/adverse effects
  4. Chan CY, Lim CY, Shahnaz Hasan M, Kwan MK
    Eur Spine J, 2016 05;25 Suppl 1:245-50.
    PMID: 27028615 DOI: 10.1007/s00586-016-4538-9
    PURPOSE: Patients with Fontan circulation have increased cardio-respiratory risk during major spinal surgery. We report a case of severe scoliosis with a Cobb angle of 123.3° in a 16-year-old boy with Fontan circulation treated with single stage posterior segmental pedicle screw instrumentation and fusion.

    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.

    CONCLUSION: From this case experience, pre-operative halo traction is a useful surgical strategy in patients with Fontan circulation with severe kyposcoliosis to achieve adequate correction without additional osteotomies to minimize the risk of surgical correction.

    Matched MeSH terms: Spinal Fusion/adverse effects
  5. Chan CYW, Chiu CK, Lee CK, Gani SMA, Mohamad SM, Hasan MS, et al.
    Spine (Phila Pa 1976), 2017 Oct 01;42(19):1427-1433.
    PMID: 28248896 DOI: 10.1097/BRS.0000000000002135
    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.

    Matched MeSH terms: Spinal Fusion/adverse effects*
  6. Chung WH, Anuar AA, Lee KJ, Hasan MS, Chiu CK, Chan CYW, et al.
    J Orthop Surg (Hong Kong), 2020 9 11;28(3):2309499020945014.
    PMID: 32909907 DOI: 10.1177/2309499020945014
    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.
    Matched MeSH terms: Spinal Fusion/adverse effects*
  7. Chan CYW, Chong JSL, Lee SY, Ch'ng PY, Chung WH, Chiu CK, et al.
    Spine (Phila Pa 1976), 2020 Dec 01;45(23):1661-1667.
    PMID: 32756286 DOI: 10.1097/BRS.0000000000003641
    STUDY DESIGN: Prospective study.

    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.

    METHODS: Fifty AIS patients operated between August 2019 and November 2019 were prospectively recruited. Parents'/patients' perceptions on three sections were evaluated: the process of the informed consent, specific operative risk which they were most concerned with and the accountability of surgeons for the surgical risks. These data were ranked and scored using a 5-point Likert Scale. Preferences were reported in mean and standard deviation. Differences in terms of preferences were studied using One-way analysis of variance (ANOVA) analysis and deemed significant when P 

    Matched MeSH terms: Spinal Fusion/adverse effects
  8. Chan CYW, Mohamad SM, Tan SH, Loh LH, Lim JN, Chiu CK, et al.
    Spine (Phila Pa 1976), 2019 03 15;44(6):389-396.
    PMID: 30153211 DOI: 10.1097/BRS.0000000000002853
    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.

    Matched MeSH terms: Spinal Fusion/adverse effects
  9. Chiu CK, Chan CYW, Tan PH, Goh SH, Ng SJ, Chian XH, et al.
    Spine (Phila Pa 1976), 2020 Mar 15;45(6):E319-E328.
    PMID: 31593064 DOI: 10.1097/BRS.0000000000003275
    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 

    Matched MeSH terms: Spinal Fusion/adverse effects
  10. Kwan MK, Chiu CK, Chan TS, Chong KI, Mohamad SM, Hasan MS, et al.
    Spine (Phila Pa 1976), 2017 Jun 01;42(11):838-843.
    PMID: 28538525 DOI: 10.1097/BRS.0000000000001902
    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.

    Matched MeSH terms: Spinal Fusion/adverse effects*
  11. Hasan MS, Choe NC, Chan CYW, Chiu CK, Kwan MK
    J Orthop Surg (Hong Kong), 2017 May-Aug;25(2):2309499017718951.
    PMID: 28675975 DOI: 10.1177/2309499017718951
    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.
    Matched MeSH terms: Spinal Fusion/adverse effects*
  12. Kwan MK, Chan CY
    Spine J, 2017 02;17(2):224-229.
    PMID: 27609611 DOI: 10.1016/j.spinee.2016.09.005
    BACKGROUND CONTEXT: With an increased cost of adolescent idiopathic scoliosis (AIS) surgery over the past 10 years, improvement of patient safety and optimization of the surgical management of AIS has become an important need. A dual attending surgeon strategy resulted in reduction of blood loss and complication rate.
    PURPOSE: This study aimed to investigate the perioperative outcome of posterior selective thoracic fusion in Lenke 1 and 2 AIS patients comparing a single versus a dual attending surgeon strategy.
    STUDY DESIGN: A prospective cohort study was carried out.
    PATIENT SAMPLE: The study sample comprised 60 patients
    OUTCOME MEASURE: Operative duration, blood loss, postoperative hemoglobin, need for transfusion, morphine usage, and duration of hospital stay were the outcome measures.
    METHODS: A total of 116 patients who underwent posterior selective thoracic fusion from two centers were prospectively recruited. The patients were grouped into Group 1 (single surgeon) and Group 2 (two surgeons). One-to-one matching analysis using "propensity score-matched cohort patient sampling method" was done for age, gender, height, weight, preoperative Cobb angle, number of fusion level, and Lenke classification. The outcome measures included operative duration, blood loss, postoperative hemoglobin, need for transfusion, morphine usage, and duration of hospital stay. This study was self-funded with no conflict of interest.
    RESULTS: From 86 patients who were operated by the two surgeons (Group 2), 30 patients were matched with 30 patients who were operated by a single surgeon (Group 1). Group 2 (164.0±25.7 min) has a significantly shorter operation duration (p=.000) compared with Group 1 (257.3±51.4 min). The total blood loss was significantly more (p=.009) in Group 1 (1254.7±521.5 mL) compared with Group 2 (893.7±518.4 mL). There were seven patients (23.3%) in Group 1 who received allogenic blood transfusion (pfusion in Lenke 1 and 2 AIS patients and will lead to a faster operation, reduced intraoperative blood loss, reduced risk of allogenic transfusion, reduced morphine requirement, and shorter hospital stay.
    Study site: University Malaya Medical Centre (UMMC), Kuala Lumpur, Malaysia
    Matched MeSH terms: Spinal Fusion/adverse effects
  13. Ong EKS, Wong TS, Chung WH, Chiu CK, Saw A, Hasan MS, et al.
    J Orthop Surg (Hong Kong), 2019 10 17;27(3):2309499019879213.
    PMID: 31615339 DOI: 10.1177/2309499019879213
    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.
    Matched MeSH terms: Spinal Fusion/adverse effects*
  14. Chan CYW, Kwan MK
    Eur Spine J, 2018 02;27(2):340-349.
    PMID: 29058137 DOI: 10.1007/s00586-017-5350-x
    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( 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%.

    Matched MeSH terms: Spinal Fusion/adverse effects*
  15. Chang KC, Samartzis D, Fuego SM, Dhatt SS, Wong YW, Cheung WY, et al.
    Bone Joint J, 2013 Jul;95-B(7):972-6.
    PMID: 23814252 DOI: 10.1302/0301-620X.95B7.30598
    Transarticular screw fixation with autograft is an established procedure for the surgical treatment of atlantoaxial instability. Removal of the posterior arch of C1 may affect the rate of fusion. This study assessed the rate of atlantoaxial fusion using transarticular screws with or without removal of the posterior arch of C1. We reviewed 30 consecutive patients who underwent atlantoaxial fusion with a minimum follow-up of two years. In 25 patients (group A) the posterior arch of C1 was not excised (group A) and in five it was (group B). Fusion was assessed on static and dynamic radiographs. In selected patients CT imaging was also used to assess fusion and the position of the screws. There were 15 men and 15 women with a mean age of 51.2 years (23 to 77) and a mean follow-up of 7.7 years (2 to 11.6). Stable union with a solid fusion or a stable fibrous union was achieved in 29 patients (97%). In Group A, 20 patients (80%) achieved a solid fusion, four (16%) a stable fibrous union and one (4%) a nonunion. In Group B, stable union was achieved in all patients, three having a solid fusion and two a stable fibrous union. There was no statistically significant difference between the status of fusion in the two groups. Complications were noted in 12 patients (40%); these were mainly related to the screws, and included malpositioning and breakage. The presence of an intact or removed posterior arch of C1 did not affect the rate of fusion in patients with atlantoaxial instability undergoing C1/C2 fusion using transarticular screws and autograft.
    Matched MeSH terms: Spinal Fusion/adverse effects
  16. Kwan MK, Chiu CK, Lee CK, Chan CY
    Bone Joint J, 2015 Nov;97-B(11):1555-61.
    PMID: 26530660 DOI: 10.1302/0301-620X.97B11.35789
    Percutaneous placement of pedicle screws is a well-established technique, however, no studies have compared percutaneous and open placement of screws in the thoracic spine. The aim of this cadaveric study was to compare the accuracy and safety of these techniques at the thoracic spinal level. A total of 288 screws were inserted in 16 (eight cadavers, 144 screws in percutaneous and eight cadavers, 144 screws in open). Pedicle perforations and fractures were documented subsequent to wide laminectomy followed by skeletalisation of the vertebrae. The perforations were classified as grade 0: no perforation, grade 1: < 2 mm perforation, grade 2: 2 mm to 4 mm perforation and grade 3: > 4 mm perforation. In the percutaneous group, the perforation rate was 11.1% with 15 (10.4%) grade 1 and one (0.7%) grade 2 perforations. In the open group, the perforation rate was 8.3% (12 screws) and all were grade 1. This difference was not significant (p = 0.45). There were 19 (13.2%) pedicle fractures in the percutaneous group and 21 (14.6%) in the open group (p = 0.73). In summary, the safety of percutaneous fluoroscopy-guided pedicle screw placement in the thoracic spine between T4 and T12 is similar to that of the conventional open technique.
    Matched MeSH terms: Spinal Fusion/adverse effects
  17. Haji Mohd Amin MZ, Beng JTB, Young BTY, Faruk Seman NA, Ching TS, Chek WC
    J Orthop Surg (Hong Kong), 2019 4 9;27(2):2309499019840083.
    PMID: 30955449 DOI: 10.1177/2309499019840083
    Cardiac arrest during scoliosis surgery is rare in idiopathic scoliosis. We present a case of cardiorespiratory collapse during corrective surgery in a young patient with idiopathic scoliosis. A diagnosis of venous air embolism was made by exclusion. A cardiorespiratory resuscitation was performed in supine position. Patient recovered without any sequelae and had operation completed 6 weeks later.
    Matched MeSH terms: Spinal Fusion/adverse effects*
  18. Kwan MK, Chiu CK, Hasan MS, Tan SH, Loh LH, Yeo KS, et al.
    Spine (Phila Pa 1976), 2019 03 15;44(6):E348-E356.
    PMID: 30130336 DOI: 10.1097/BRS.0000000000002848
    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.

    Matched MeSH terms: Spinal Fusion/adverse effects
  19. Chan CY, Kwan MK, Saw LB
    Eur Spine J, 2010 Jan;19(1):78-84.
    PMID: 19763636 DOI: 10.1007/s00586-009-1157-8
    The objective of this cadaveric study is to determine the safety and outcome of thoracic pedicle screw placement in Asians using the funnel technique. Pedicle screws have superior biomechanical as well as clinical data when compared to other methods of instrumentation. However, misplacement in the thoracic spine can result in major neurological implications. There is great variability of the thoracic pedicle morphometry between the Western and the Asian population. The feasibility of thoracic pedicle screw insertion in Asians has not been fully elucidated yet. A pre-insertion radiograph was performed and surgeons were blinded to the morphometry of the thoracic pedicles. 240 pedicle screws were inserted in ten Asian cadavers from T1 to T12 using the funnel technique. 5.0 mm screws were used from T1 to T6 while 6.0 mm screws were used from T7 to T12. Perforations were detected by direct visualization via a wide laminectomy. The narrowest pedicles are found between T3 and T6. T5 pedicle width is smallest measuring 4.1 +/- 1.3 mm. There were 24 (10.0%) Grade 1 perforations and only 1 (0.4%) Grade 2 perforation. Grade 2 or worse perforation is considered significant perforation which would threaten the neural structures. There were twice as many lateral and inferior perforations compared to medial perforations. 48.0% of the perforations occurred at T1, T2 and T3 pedicles. Pedicle fracture occurred in 10.4% of pedicles. Intra-operatively, the absence of funnel was found in 24.5% of pedicles. In conclusion, thoracic pedicle screws using 5.0 mm at T1-T6 and 6.0 mm at T7-T12 can be inserted safely in Asian cadavers using the funnel technique despite having smaller thoracic pedicle morphometry.
    Matched MeSH terms: Spinal Fusion/adverse effects
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