1.Chondrosarcoma of the T2 Vertebra Using a Combined Anterior and Posterior Approach: A Case Report
Mun Keong Kwan ; Norazian Kamisan ; Lim Beng Saw
Malaysian Orthopaedic Journal 2010;4(3):22-25
Chondrosarcoma of the spine is rare; it presents predominantly in very young males and presentation with neurological deficit is uncommon. Treatment of this type of tumour is mainly through surgery as adjuvant therapy is ineffective. En bloc resection of tumours in the spine are difficult although it remains the recommended treatment for chondrosarcoma. We report here presentation of a female with paresis (Frankel C) whot was diagnosed with a large chondrosarcoma of the T2 vertebra extending to the right upper thoracic cavity. The patient underwent radical excision through an anterior and posterior approach to the spine.
2.Correction of Severe Thoracolumbar Spondylolisthesis (Grade 4) Secondary to Neurofibromatosis with Posterior Spinal Instrumented Fusion Alone. A Case Report
Muhammad Mohamed Tahir ; Mun Keong Kwan ; Chris Yin Wei Chan ; Lim Beng Saw ; Dar Wen Goh
The Medical Journal of Malaysia 2012;67(6):633-635
A 15-year-old teenager with Type 1 Neurofibromatosis
presented with grade 4 spondylolisthesis over T12/L1
junction resulting paraparesis (Frankel D). Radiograph
showed a Cobb angle of 88 degrees. Computed tomography
scan showed dysplastic vertebral bodies, pedicles and facet
joints of T11, T12 and L1 vertebra with complete T12/L1
facets dislocation. Magnetic resonance imaging confirmed
presence of spinal cord compression. He underwent
posterior instrumentation and posterolateral fusion (T8 to
L4) using hybrid instrumentation. Extensive corticotomy of
the posterior elements was followed by the use of large
amount of bone graft. Post operatively, his neurology
improved markedly back to normal. Radiographs showed a
good correction of the deformity. He was immobilized in a
thoracolumbar orthosis for six months. A solid posterior
fusion was achieved at six months follow up. At 36-month
follow up, he remained asymptomatic. This case report
illustrates a successful treatment of a grade 4
thoracolumbar spondylolisthesis secondary to
neurofibromatosis with posterior spinal fusion alone.
3.Safety of Pedicle Screws in Adolescent Idiopathic Scoliosis Surgery.
Chris Yin Wei CHAN ; Mun Keong KWAN
Asian Spine Journal 2017;11(6):998-1007
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.
Adolescent*
;
Esophagus
;
Humans
;
Incidence
;
Pedicle Screws*
;
Scoliosis*
;
Spine
4.Surgical Morphometry of C1 and C2 Vertebrae: A Three-Dimensional Computed Tomography Analysis of 180 Chinese, Indian, and Malay Patients.
Chee Kean LEE ; Tiam Siong TAN ; Chris Yin Wei CHAN ; Mun Keong KWAN
Asian Spine Journal 2017;11(2):181-189
STUDY DESIGN: Clinical imaging study. 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.
Asian Continental Ancestry Group*
;
Humans
;
Pedicle Screws
;
Spine*
5.Ultra Long Construct Minimally Invasive Spinal Stabilization Using Percutaneous Pedicle Screws in the Treatment of Symptomatic Multicentric Spinal Metastasis.
Chee Kean LEE ; Chris Yin Wei CHAN ; Mun Keong KWAN
Asian Spine Journal 2015;9(6):962-965
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.
Decompression
;
Female
;
Fractures, Spontaneous
;
Humans
;
Lung Neoplasms
;
Middle Aged
;
Neoplasm Metastasis*
;
Neurology
;
Radiotherapy
;
Spinal Cord Compression
;
Spine
6.Minimally Invasive Spinal Stabilization Using Fluoroscopic-Guided Percutaneous Screws as a Form of Palliative Surgery in Patients with Spinal Metastasis.
Mun Keong KWAN ; Chee Kean LEE ; Chris Yin Wei CHAN
Asian Spine Journal 2016;10(1):99-110
STUDY DESIGN: Prospective cohort study. PURPOSE: To report the outcome of 50 patients with spinal metastases treated with minimally invasive stabilization (MISt) using fluoroscopic guided percutaneous pedicle screws with/without minimally invasive decompression. OVERVIEW OF LITERATURE: The advent of minimally invasive percutaneous pedicle screw stabilization system has revolutionized the treatment of spinal metastasis. METHODS: Between 2008 and 2013, 50 cases of spinal metastasis with pathological fracture(s) with/without neurology deficit were treated by MISt at our institution. The patients were assessed by Tomita score, pain score, operation time, blood loss, neurological recovery, time to ambulation and survival. RESULTS: The mean Tomita score was 6.3+/-2.4. Thirty seven patients (74.0%) required minimally invasive decompression in addition to MISt. The mean operating time was 2.3+/-0.5 hours for MISt alone and 3.4+/-1.2 hours for MISt with decompression. Mean blood loss for MISt alone and MISt with decompression was 0.4+/-0.2 L and 1.7+/-0.9 L, respectively. MISt provided a statistically significant reduction in visual analog scale pain score with mean preoperative score of 7.9+/-1.4 that was significantly decreased to 2.5+/-1.2 postoperatively (p=0.000). For patients with neurological deficit, 70% displayed improvement of one Frankel grade and 5% had an improvement of 2 Frankel grades. No patient was bed-ridden postoperatively, with the average time to ambulation of 3.4+/-1.8 days. The mean overall survival time was 11.3 months (range, 2-51 months). Those with a Tomita score <8 survived significantly longer than those a Tomita score > or =8 with a mean survival of 14.1+/-12.5 months and 6.8+/-4.9 months, respectively (p=0.019). There were no surgical complications, except one case of implant failure. CONCLUSIONS: MISt is an acceptable treatment option for spinal metastatic patients, providing good relief of instability back pain with no major complications.
Back Pain
;
Cohort Studies
;
Decompression
;
Fractures, Spontaneous
;
Humans
;
Neoplasm Metastasis*
;
Neurology
;
Palliative Care*
;
Prospective Studies
;
Visual Analog Scale
;
Walking
7.Neurological Recovery in Two Patients with Cauda Equina Syndrome Secondary to L5 Lumbar Spine Giant Cell Tumour after Treatment with Denosumab without Surgery.
Simret Singh RANDHAWA ; Angel Khor Nee KWAN ; Chee Kidd CHIU ; Chris Yin Wei CHAN ; Mun Keong KWAN
Asian Spine Journal 2016;10(5):945-949
We report two patients with cauda equina syndrome (CES) secondary to L5 giant cell tumour (GCT) who achieved good neurological recovery after treatment with denosumab without surgery. The first patient was a 26-year-old man with L5 GCT causing CES who regained bowel and urinary control, muscle power improvement from grade 2 to grade 4 and Oswestry disability index (ODI) improvement from 48 to 23 after denosumab treatment. The second patient was a 25-year-old woman with L5 GCT causing CES who regained bowel and urinary control, muscle power improvement from grade 0 to grade 4 and ODI improvement from 42 to 20 after denosumab treatment. The usage of denosumab in the treatment of patients with CES due to GCT allows potential neurological recovery without any surgical intervention. If surgery is not contraindicated, more time is obtained to prepare the patient preoperatively to attain safer surgery and to achieve complete tumour clearance.
Adult
;
Cauda Equina*
;
Denosumab*
;
Female
;
Giant Cells*
;
Humans
;
Polyradiculopathy*
;
Spine*
8.Femoral head diameter in the Malaysian population.
Chee Kean LEE ; Mun Keong KWAN ; Azhar Mahmood MERICAN ; Wuey Min NG ; Lim Beng SAW ; Kok Kheng TEH ; Manoharan KRISHNAN ; Ramanathan RAMIAH
Singapore medical journal 2014;55(8):436-438
INTRODUCTIONHip arthroplasty is commonly performed worldwide. The objective of this study was to determine the diameter of the femoral head in the Malaysian population in relation to gender and race (i.e. among Malay, Chinese and Indian patients).
METHODSThis was a retrospective cross-sectional study performed between January 1995 and December 2006, evaluating the femoral head diameters of all patients aged 50 years and above who underwent hemiarthroplasty at two major hospitals in Malaysia.
RESULTSA total of 945 femoral heads (663 women, 282 men) were evaluated. The mean age of the patients in our cohort was 75.2 ± 9.4 (range 50-101) years. The mean femoral head diameter (with intact articular cartilage) was 44.9 ± 3.2 (range 38-54) mm. In our study, men had a significantly larger mean femoral head diameter than women (47.7 ± 2.8 mm vs. 43.7 ± 2.4 mm; p < 0.05). Patients of Chinese ethnicity were also found to have significantly larger femoral head diameters, when compared among the three races studied (p < 0.05).
CONCLUSIONMalaysians have a mean femoral head diameter of 44.9 ± 3.2 mm. Among our patients, Chinese patients had a significantly larger femoral head size than Malay and Indian patients. We also found that, in our cohort, men had significantly larger femoral head diameters than women.
Aged ; Aged, 80 and over ; Arthroplasty, Replacement, Hip ; Asian Continental Ancestry Group ; Cross-Sectional Studies ; Female ; Femur Head ; anatomy & histology ; pathology ; Humans ; Malaysia ; Male ; Middle Aged ; Reference Values ; Retrospective Studies
9.APSS-ASJ Best Clinical Research Award: Is There a Difference between Patients' and Parents' Perception of Physical Appearance in Adolescent Idiopathic Scoliosis?
Chris Yin Wei CHAN ; Siti Mariam Abd GANI ; Min Yuen LIM ; Chee Kidd CHIU ; Mun Keong KWAN
Asian Spine Journal 2019;13(2):216-224
STUDY DESIGN: Prospective study. PURPOSE: To compare Patients' and parents’ perceptions of physical attributes (PAs) of adolescent idiopathic scoliosis (AIS) patients and to report any correlations between their perceptions and Scoliosis Research Society-22r (SRS-22r) scores. OVERVIEW OF LITERATURE: Few studies have looked into the differences between Patients' and parents’ perceptions of their appearance. METHODS: AIS patient–parent pairs (n=170) were recruited. The Patients' and parents’ perceptions of six PAs were evaluated: waist asymmetry (WA), rib hump (RH), shoulder asymmetry (SA), neck tilt, breast asymmetry (BrA), and chest prominence. These PAs were ranked, and an aggregate PA (Agg-PA) score was derived from a score assigned to the attribute (6 for the most important PA and 1 for the least important). The patients also completed the SRS-22r questionnaire. RESULTS: Ninety-nine patients (58.2%) and 71 patients (41.8%) had thoracic and lumbar major curves, respectively. WA was ranked first by 54 patients (31.8%) and 50 parents (29.4%), whereas RH was ranked first by 50 patients (29.4%) and 38 parents (22.4%). The overall Agg-PA scores were similar for patients and parents (p>0.05). However, for thoracic major curves (TMCs) >40°, a significant difference was noted between the Agg-PA scores of patients and parents for SA (3.5±1.6 vs. 4.2±1.6, p=0.041) and BrA (3.0±1.6 vs. 2.2±1.3, p=0.006). For TMCs <40°, a significant difference was found between the Agg-PA scores of patients and parents for WA (3.7±1.6 vs. 4.4±1.5, p=0.050). BrA was negatively correlated with total SRS-22r score. CONCLUSIONS: There were no significant differences between patients and parents in their ranking of the most important PAs. For TMCs >40°, there were significant differences in the Agg-PA for SA and BrA. Pa¬tients were more concerned about BrA and parents were more concerned about SA. Patients' perception of the six PAs had weak correlation with SRS-22r scores.
Adolescent
;
Awards and Prizes
;
Body, Physical Appearance
;
Breast
;
Humans
;
Neck
;
Parents
;
Prospective Studies
;
Ribs
;
Scoliosis
;
Shoulder
;
Thorax
10.Neuropathic Pain after Adolescent Idiopathic Scoliosis Correction Surgery
Mohd Shahnaz HASAN ; Khean Jin GOH ; Hing Wa YIP ; Siti Mariam MOHAMAD ; Teik Seng CHAN ; Kok Ian CHONG ; Amber HASEEB ; Chee Kidd CHIU ; Chris Chan Yin WEI ; Mun Keong KWAN
Asian Spine Journal 2021;15(5):628-635
Methods:
Forty AIS patients were recruited. Demographic, preoperative, and postoperative data were recorded. The magnitude and characteristics of postoperative pain were assessed using the painDETECT questionnaire through telephone enquiries at intervals of 2, 6, 12, and 24 weeks. Statistical analyses were followed by Pearson correlation test to determine the relationship between pain scores at 6, 12, and 24 weeks with the risk factors.
Results:
Based on the painDETECT questionnaire, 90% of the patients had nociceptive pain, and 10% had a possible neuropathic pain component at 2 weeks postoperatively as per a mean painDETECT score of 7.1±4.5. Assessments at 6, 12, and 24 weeks showed that no patients had neuropathic pain with painDETECT scores of 4.4±3.2, 2.9±2.9, and 1.5±2.0, respectively. There was a significant correlation between total postoperative morphine use during 48 hours after the surgery and a tendency to develop neuropathic pain (p=0.022).
Conclusions
Chronic neuropathic pain was uncommon in AIS patients who had undergone PSF surgery. Higher opioid consumption will increase the possibility of developing chronic neuropathic pain.