Displaying publications 1 - 20 of 132 in total

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  1. Kwan MK, Saw A, Sara Ahmad T
    Med J Malaysia, 2005 Mar;60(1):112-4.
    PMID: 16250295 MyJurnal
    We are reporting four cases of serious washing machine related injury that presented within a period of 5 months. All patients were young children with the mean age of 9 year-old and three had their dominant hand injured. The washing machines involved were the automatic top loader type and all injuries occurred during the spinning phase. Serious automatic washing machine injury is not uncommon in Malaysia. We feel that there is a need to improve the safety features especially during the spinning phase. The operating instructions and safety precautions on the washing machine should be displayed in different languages that can be understood well. Parents should also aware of the potential risks of this seemingly benign household appliance.
  2. Kwan MK, Penafort R, Saw A
    Med J Malaysia, 2004 Dec;59 Suppl F:39-41.
    PMID: 15941159
    Joint stiffness is one of the complications of limb procedure. It developes as a result of failure of knee flexors to lengthen in tandem with the bone, especially when there is inadequate physical therapy to provide active and passive mobilization of the affected joint. We are reporting four patients who developed fixed flexion contracture of their knees during bone lengthening procedure for the tibia with Ilizarov external fixator. Three of them were treated for congenital pseudoarthrosis and one was for fibular hemimelia. None of them were able to visit the physiotherapist even on a weekly basis. A splint was constructed from components of Ilizarov external fixator and applied on to the existing frame to passively extend the affected knee. Patients and their family members were taught to perform this exercise regularly and eventually near complete correction were achieved. With this result, we would like to recommend the use of this "Passive Knee Extension Splint" to avoid knee flexion Contracture during limb lengthening procedures with Ilizarov external fixators.
  3. Kwan MK, Chan CY
    Eur Spine J, 2016 10;25(10):3065-3074.
    PMID: 27021616
    PURPOSE: To investigate whether an optimal upper instrumented vertebra (UIV) tilt angle would prevent 'lateral' shoulder imbalance or neck tilt (with 'medial' shoulder imbalance) post-operatively.

    METHODS: The mean follow-up for 60 AIS (Lenke 1 and Lenke 2) patients was 49.3 ± 8.4 months. Optimal UIV tilt angle was calculated from the cervical supine side bending radiographs. Lateral shoulder imbalance was graded using the clinical shoulder grading. The clinical neck tilt grading was as follows: Grade 0: no neck tilt, Grade 1: actively correctable neck tilt, Grade 2: neck tilt that cannot be corrected by active contraction and Grade 3: severe neck tilt with trapezial asymmetry >1 cm. T1 tilt, clavicle angle and cervical axis were measured. UIVDiff (difference between post-operative UIV tilt and pre-operative Optimal UIV tilt) and the reserve motion of the UIV were correlated with the outcome measures. Patients were assessed at 6 weeks and at final follow-up with a minimum follow-up duration of 24 months.

    RESULTS: Among patients with grade 0 neck tilt, 88.2 % of patients had the UIV tilt angle within the reserve motion range. This percentage dropped to 75.0 % in patients with grade 1 neck tilt whereas in patients with grade 2 and grade 3 neck tilt, the percentage dropped further to 22.2 and 20.0 % (p = 0.000). The occurrence of grade 2 and 3 neck tilt when UIVDiff was <5°, 5-10° and >10° was 9.5, 50.0 and 100.0 %, respectively (p = 0.005). UIVDiff and T1 tilt had a positive and strong correlation (r2 = 0.618). However, UIVDiff had poor correlation with clavicle angle and the lateral shoulder imbalance.

    CONCLUSION: An optimal UIV tilt might prevent neck tilt with 'medial' shoulder imbalance due to trapezial prominence and but not 'lateral' shoulder imbalance.

  4. Chan CYW, Kwan MK
    Spine (Phila Pa 1976), 2016 Jun;41(11):E694-E699.
    PMID: 26656053 DOI: 10.1097/BRS.0000000000001349
    STUDY DESIGN: Prospective study.

    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 

  5. 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 (p
  6. 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%.

  7. Chan CYW, Kwan MK
    Asian Spine J, 2017 Dec;11(6):998-1007.
    PMID: 29279757 DOI: 10.4184/asj.2017.11.6.998
    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.
  8. Saw A, Kwan MK, Sengupta S
    Singapore Med J, 2004 Apr;45(4):180-2.
    PMID: 15094988
    Acupuncture is used for some conditions as an alternative to medication or surgical intervention. Several complications had been reported, and they are generally due to physical injury by the needle or transmission of diseases. We report a case of life-threatening necrotising fasciitis that developed after acupuncture treatment for osteoarthritis of the knee in a 55-year-old diabetic woman. She presented with multiple discharging sinuses over the right knee. As the patient did not respond to intravenous antibiotics, extensive debridement was performed. She made a good recovery. Since many old diabetic patients with degenerative joint diseases may consider this mode of treatment, guidelines on cleanliness and sterility of this procedure should be developed and practiced.
  9. Chan CK, Saw A, Kwan MK, Karina R
    J Orthop Surg (Hong Kong), 2009 Apr;17(1):19-22.
    PMID: 19398787
    To compare infection rates associated with 2 dressing solutions for metal-skin interfaces.
  10. Ng SS, Kwan MK, Ahmad TS
    Med J Malaysia, 2006 Dec;61 Suppl B:13-7.
    PMID: 17600987
    This study is designed to evaluate twenty patients after sural nerve harvest using the single longitudinal incision method. The area of sensory loss to pin prick was assessed by the authors at different intervals. Donor site factors, scar cosmesis, functional status and complications were assessed using a questionnaire. The mean area of anaesthesia at one month was 65 cm2 and it had reduced by 77% to 15 cm2 at one and a half years. The mean area of reduced sensation was 49 cm2 at one month and it increased by 18% to 58 cm2 over the same period. Therefore, the total area of sensory deficit was reduced by 36% from 114 cm2 at one month to 73 cm2 at one and a half years. Subjective patient evaluation indicated moderate level of pain during immediate post surgical period, which reduced significantly at one month. A low level of neuroma symptoms was recorded throughout the study period. At a mean follow-up period of two years, there was no area of anaesthesia in 50% of the patients. Mean area of anaesthesia for all patients was 12 cm2 and mean area of reduced sensation was 55 cm2. Subjective patient evaluation indicated a low level of pain, neuroma symptoms and numbness over the sural nerve sensory distribution. Twenty five percent of the patients were not satisfied with the scar appearance. Function and daily activities were not affected significantly. No surgical complications were observed.
  11. Chua YP, Kwan MK, Saw A
    Med J Malaysia, 2005 Jul;60 Suppl C:78-82.
    PMID: 16381289
    The need for perioperative blood transfusion in elderly patients with trochanteric fracture scheduled for elective dynamic hip screw fixation has recently been questioned following reports on the association between allogeneic blood transfusion and post-operative infections. This retrospective study was undertaken to assess the amount of per operative blood loss and transfusion requirement in relation to pre-operative haemoglobin level in 198 patients with trochanteric fractures. The average per operative blood loss was 409 ml and it correlated well with the duration of the operation. More than half of the patients (52.5%) required blood transfusion and nearly three-quarters were anaemic prior to the surgery. Proactive pre-operative measures to optimize the patient's haemoglobin level and intra-operative minimization of blood loss are essential steps to obviate the need for perioperative allogeneic blood transfusion.
  12. Kwan MK, Marican AM, Ahmad TS
    Med J Malaysia, 2005 Jul;60 Suppl C:104-7.
    PMID: 16381293
    Soft tissue loss of the heel is difficult to treat as it may cause significant morbidity particularly recurrent ulceration and subsequent chronic osteomyelitis. Reconstruction of such defect with local flap can provide good result. We report our experience in treating four patients with heel defect using the in-step island flap. The flap, which is based on the medial plantar neurovascular pedicle, provides a sensate durable tissue required for weight-bearing and normal gait.
  13. Kwan MK, Chooi WK, Lim HH
    Med J Malaysia, 2004 Dec;59 Suppl F:14-8.
    PMID: 15941155
    Between April 1998 and December 1999, thirty patients with Idiopathic Scoliosis were operated with Multisegmented Hook-Rod System. These patients were operated at the mean age of 16 years and were followed up for a mean of 22.3 months (range 13-34 months). Seven patients had anterior release to increase the curve flexibility followed by second stage posterior instrumentation on the same day. The average operating time for a posterior instrumentation alone and anterior release combined with posterior instrumentation were 270 minutes and 522 minutes respectively. The average blood loss was 2.2 litres for posterior instrumentation alone and 3.3 litres for single day anterior release and posterior surgery. The mean preoperative Cobb's angle was 70 degrees. The mean immediate postoperative and final follow up Cobb's angles were 38 and 42 degrees, which represented an average coronal plane correction of 46.7% and 40.0% respectively. The mean preoperative apical vertebral rotation was 25 degrees, which improved to 15 degrees after the operation. At final follow up, the mean apical vertebra rotation was 20 degrees, which represented a mean apical vertebral rotation correction of 20%. Complications of the procedure included one transient neurological deficit, one infection, one graft site infection and one case of screw cut out. We were able to obtain satisfactory correction of idiopathic scoliosis with the Multisegmented Hook-Rod System.
  14. Chiu CK, Chan C, Kwan MK
    Malays Orthop J, 2014 Nov;8(3):27-9.
    PMID: 26401232 MyJurnal DOI: 10.5704/MOJ.1411.006
    A method of transpedicular bone grafting using contrast impregnated bone to improve the visualization of bone graft on the image intensifier is reported. A - 36-year old man who had sustained traumatic burst fracture of T12 vertebra, with Load-Sharing Classification (LSC) score of 8, was treated with posterior short segment fusion from T11 to L1 with transpedicular bone graft of T12 vertebra. We were able to correct the kyphotic end plate angle (EPA) from 19º to 1.4º. Anterior bone graft augmentation was achieved with contrast enhaced transpedicular bone grafts. At six months follow up, CT scan showed good bony integration of the anterior column with EPA of 4.5º and two years later, radiographs showed EPA of 7.6 º.
  15. Ng WM, Kwan MK, Merican AM
    Singapore Med J, 2006 Jan;47(1):71-4.
    PMID: 16397726
    Melioidosis is caused by an infection by Burkholderia pseudomallei. Osteomyelitis is a recognised manifestation of melioidosis but Burkholderia pseudomallei is a relatively rare aetiological agent in musculoskeletal infections. We report a 32-year-old diabetic man with septicaemia due to melioidotic infection of the spleen, liver and distal femur. The osteomyelitis relapsed despite being treated with the standard radical debridement and insertion of gentamycinimpregnated polymethylmetacrylate (PMMA) beads, followed by an optimal antibiotic therapy. The PMMA-gentamycin beads were then removed. The bone defect was debrided and packed with calcium hydroxyapatite blocks filled with ceftazidime powder. The osteomyelitis was successfully treated and the patient remained free of infection four years postoperatively. Computed tomography demonstrated successful incorporation of the calcium hydroxyapatite into host bone.
  16. Lee CK, Chan CY, Kwan MK
    Asian Spine J, 2015 Dec;9(6):962-5.
    PMID: 26713131 DOI: 10.4184/asj.2015.9.6.962
    Managing multiple level spinal metastases is challenging. We report the case of a 58-year-old female with advanced lung cancer who presented with multiple pathological fractures of the thoracic spine (T5, T6, T7, and T8 vertebrae). She was treated with palliative radiotherapy. Her resting pain improved, but the instability pain persisted. One month later, she had a trivial fall leading to a pathological fracture of the L2 vertebra with cauda equine syndrome. The patient was treated surgically with minimally invasive decompression of the L2 and with percutaneous instrumented stabilization using an ultra-long construct from T3 to L5 (15 spinal levels), spanning the previously radiated zone and the decompression site. Postoperatively, she had significant improvements in pain and neurology. There were no surgical complications. Ultra long construct minimally invasive spinal stabilization is the ideal approach for symptomatic multicentric spinal metastasis with poor prognostic scores. Using this technique, the goals of spinal stabilization and direct neural decompression can be achieved with minimal morbidity.
  17. Chan CY, Kwan MK, Saw LB, Hussin P
    Clin Spine Surg, 2016 May 26.
    PMID: 24141340
    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 rhBMP-2.
  18. Kwan M, Chan C, Ng W, Merican A, Chung W, Chan S
    Malays Orthop J, 2013 Jul;7(2):12-7.
    PMID: 25722819 MyJurnal DOI: 10.5704/MOJ.1307.008
    There are reported cases of cortical reaction over the tension side of the normal femoral shafts in patients on long term treatment with alendronate, leading to subsequent femoral shaft fractures. We performed a retrospective review of patients with low-energy femoral shaft fracture on alendronate, admitted to our institution during the period 2004 to May 2009. The presence of radiological changes of cortical hypertrophy with or without Looser's zone over the tension side of the femoral bone (normal limb) was determined and correlated with clinical symptoms. Thirteen patients were identified. Average duration of alendronate use was 6.5 ± 3.3 years (ranges, two to 10 years). These radiological changes were noted in four patients. Average duration of alendronate usage in these four patients was 6.5 ± 2.4 years (ranges, 5 to10 years). Prodromal thigh pain was present in a patient, who had cortical hypertrophy with the presence of a Looser's zone traversing the cortex on the femoral shaft. One patient had Looser's zone limited at the lateral hypertrophied cortex without prodromal pain. The interobserver kappa coefficient was 0.96. A femoral radiograph should be performed in all patients who are on long-term alendronate therapy who present with thigh pain. We propose a new grading system based on our observation of the radiological features in these four cases. This new grading of the radiological spectrum of femoral shaft cortical pathology has the potential to stratify the risk of low energy femoral fracture for patients treated with long-term alendronate therapy.
  19. Kwan MK, Jeffry A, Chan CY, Saw LB
    Surg Radiol Anat, 2012 Apr;34(3):217-27.
    PMID: 22194086 DOI: 10.1007/s00276-011-0919-2
    Studies of sacral pedicle anatomy have been reported in the European population. However, the feasibility for the use of S1, S2 and S2-ilium screws has not been fully investigated in the Asian population.
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