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  1. Sivananthan KS
    Med J Malaysia, 2001 Jun;56 Suppl C:1-2.
    PMID: 11814241
    Matched MeSH terms: Spinal Diseases/surgery*
  2. J Orthop Surg (Hong Kong), 2011 Apr;19(1):1-2.
    PMID: 21519066
    Matched MeSH terms: Spinal Diseases/surgery
  3. Razak M, Mahmud M, Mokhtar SA, Omar A
    Med J Malaysia, 2000 Sep;55 Suppl C:14-7.
    PMID: 11200038
    Fifteen cases of unstable fracture-dislocation of the thoracolumbar spine have been treated by open reduction, short segment transpedicular fixation and fusion in Universiti Unit, Kuala Lumpur Hospital from January 1994 until December 1997. Twelve male and three female patients were injured; their age ranged from 18 to 45 years. Five fracture-dislocations occurred in the lower thoracic spine (T8 to T11), eight at the thoracolumbar junction (T12 to L2) and two in the lumbar spine (L3 to L5). All the patients had neurological deficit. Seven patients with incomplete or cauda equina lesions regained some neural function, while all eight with complete lesions remained unchanged. Ten of the fifteen cases were grossly unstable and translated beyond 50% of the width of the spinal column. At the time of follow up (more than one year in all patients), no loss of reduction or of fixation was noted in any patient. Solid fusion was achieved in all patients. The advantages of this method of treatment include stable fixation, with maintenance of sagittal and coronal spinal alignments, to allow early rehabilitation.
    Matched MeSH terms: Spinal Diseases/surgery*
  4. Chiu CK, Chan CYW, Cheung JPY, Cheung PWH, Gani SMA, Kwan MK
    J Orthop Surg (Hong Kong), 2021 2 12;29(1):2309499020988176.
    PMID: 33569998 DOI: 10.1177/2309499020988176
    PURPOSE: In this study we investigated on the personal protective equipment (PPE) usage, recycling, and disposal among spine surgeons in the Asia Pacific region.

    METHODS: A cross-sectional survey was carried out among spine surgeons in Asia Pacific. The questionnaires were focused on the usage, recycling and disposal of PPE.

    RESULTS: Two hundred and twenty-two surgeons from 19 countries participated in the survey. When we sub-analysed the differences between countries, the provision of adequate PPE by hospitals ranged from 37.5% to 100%. The usage of PPE was generally high. The most used PPE were surgical face masks (88.7%), followed by surgical caps (88.3%), gowns (85.6%), sterile gloves (83.3%) and face shields (82.0%). The least used PPE were powered air-purifying respirators (PAPR) (23.0%) and shoes/boots (45.0%). The commonly used PPE for surgeries involving COVID-19 positive patients were N95 masks (74.8%), sterile gloves (73.0%), gowns (72.1%), surgical caps (71.6%), face shields (64.4%), goggles (64.0%), shoe covers (58.6%), plastic aprons (45.9%), shoes/boots (45.9%), surgical face masks (36.5%) and PAPRs (21.2%). Most PPE were not recycled. Biohazard bins were the preferred method of disposal for all types of PPE items compared to general waste.

    CONCLUSIONS: The usage of PPE was generally high among most countries especially for surgeries involving COVID-19 positive patients except for Myanmar and Nepal. Overall, the most used PPE were surgical face masks. For surgeries involving COVID-19 positive patients, the most used PPE were N95 masks. Most PPE were not recycled. Biohazard bins were the preferred method of disposal for all types of PPE.

    Matched MeSH terms: Spinal Diseases/surgery*
  5. Kwan MK, Chiu CK, Chan CYW, Zamani R, Hansen-Algenstaedt N
    J Orthop Surg (Hong Kong), 2017 7 28;25(2):2309499017722438.
    PMID: 28748740 DOI: 10.1177/2309499017722438
    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.

    Matched MeSH terms: Spinal Diseases/surgery*
  6. Chiu CK, Chan CYW, Kwan MK
    J Orthop Surg (Hong Kong), 2017 May-Aug;25(2):2309499017713938.
    PMID: 28705124 DOI: 10.1177/2309499017713938
    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.
    Matched MeSH terms: Spinal Diseases/surgery*
  7. Chiu CK, Kwan MK, Chan CY, Schaefer C, Hansen-Algenstaedt N
    Bone Joint J, 2015 Aug;97-B(8):1111-7.
    PMID: 26224830 DOI: 10.1302/0301-620X.97B8.35330
    We undertook a retrospective study investigating the accuracy and safety of percutaneous pedicle screws placed under fluoroscopic guidance in the lumbosacral junction and lumbar spine. The CT scans of patients were chosen from two centres: European patients from University Medical Center Hamburg-Eppendorf, Germany, and Asian patients from the University of Malaya, Malaysia. Screw perforations were classified into grades 0, 1, 2 and 3. A total of 880 percutaneous pedicle screws from 203 patients were analysed: 614 screws from 144 European patients and 266 screws from 59 Asian patients. The mean age of the patients was 58.8 years (16 to 91) and there were 103 men and 100 women. The total rate of perforation was 9.9% (87 screws) with 7.4% grade 1, 2.0% grade 2 and 0.5% grade 3 perforations. The rate of perforation in Europeans was 10.4% and in Asians was 8.6%, with no significant difference between the two (p = 0.42). The rate of perforation was the highest in S1 (19.4%) followed by L5 (14.9%). The accuracy and safety of percutaneous pedicle screw placement are comparable to those cited in the literature for the open method of pedicle screw placement. Greater caution must be taken during the insertion of L5 and S1 percutaneous pedicle screws owing to their more angulated pedicles, the anatomical variations in their vertebral bodies and the morphology of the spinal canal at this location.
    Matched MeSH terms: Spinal Diseases/surgery*
  8. Lee CK, Tan TS, Chan C, Kwan MK
    J Orthop Surg (Hong Kong), 2017 01;25(1):2309499017692683.
    PMID: 28211302 DOI: 10.1177/2309499017692683
    INTRODUCTION: C1 lateral mass (C1LM) screw is a common procedure in spine surgery. However, related studies are lacking in Asia. We aim to determine the safety of C1LM screw for the Chinese, Indians, and Malays.

    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.

    Matched MeSH terms: Spinal Diseases/surgery*
  9. 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 Diseases/surgery*
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