Endothelium dependent hyperpolarization-type relaxation compensates for attenuated nitric oxide-mediated responses in subcutaneous arteries of diabetic patients.

Diabetes impairs endothelium-dependent relaxations. The present study evaluated the contribution of different endothelium-dependent relaxing mechanisms to the regulation of vascular tone in subcutaneous blood vessels of humans with Type 2 diabetes mellitus. Subcutaneous arteries were isolated from tissues of healthy controls and diabetics. Vascular function was determined using wire myography. Expressions of proteins were measured by Western blotting and immunostaining. Endothelium-dependent relaxations to acetylcholine were impaired in arteries from diabetics compared to controls (P = 0.009). Acetylcholine-induced nitric oxide (NO)-mediated relaxations [in the presence of an inhibitor of cyclooxygenases (COX; indomethacin) and small and intermediate conductance calcium-activated potassium channel blockers (UCL1684 and TRAM 34, respectively)] were attenuated in arteries from diabetics compared to controls (P < 0.001). However, endothelium-dependent hyperpolarization (EDH)-type relaxations [in the presence of indomethacin and the NO synthase blocker, l-NAME] were augmented in arteries from diabetics compared to controls (P = 0.003). Endothelium-independent relaxations to sodium nitroprusside (NO donor) and salbutamol (ß-adrenoceptor agonist) were preserved, but those to prostacyclin were attenuated in diabetics compared to controls (P = 0.017). In arteries of diabetics, protein expressions of endothelial NO synthase, prostacyclin synthase and prostacyclin receptors were decreased, but those of COX-2 were increased. These findings suggest that in human diabetes, the impairment of endothelium-dependent relaxations is caused by a diminished NO bioavailability; however, EDH appears to compensate, at least in part, for this dysfunction.

Near-1: the evaluation of usability and task load demand of a motorized lifter for patient transfer.

PURPOSE: Despite the proven benefits of motorized lifting devices in reducing the physical stresses experienced by nurses during patient transfers, the low adoption of these devices remains limited. The study aimed to assess the perceptions of nurses regarding the new motorized lifting device (NEAR-1) in terms of their perceived workload and usability during patient transfers. MATERIALS AND METHODS: A cross-sectional study was conducted to evaluate the perceptions of nurses (n = 45) and students (n = 6) when performing patient transfers from bed to wheelchair and vice versa using the NEAR-1 compared to an existing floor lift, walking belt, and manual transfer. Participants filled out surveys evaluating the perceived task demands and usability of the NEAR-1, as well as open-ended interviews. RESULTS: The use of the NEAR-1 significantly reduced the mean of all NASA-TLX constructs (p < 0.001) when compared to manual transfer. When comparing with other existing lifting devices, the NEAR-1 (24.4 ± 3.0) recorded the lowest overall score of NASA-TLX perceived workload, followed by the existing floor lift (26.1 ± 11.6), a robotic-assisted transfer device (28.3 ± 6.8) and mechanical floor lift (31.5 ± 9.3). The participants recorded a usability score of 76.86, indicating positive perceptions of the nurses towards the technology. CONCLUSIONS: Overall, the NEAR-1 has the potential to reduce the physical stresses on nurses and decrease the likelihood of work-related musculoskeletal disorders (WMSDs). The NEAR-1 may represent a promising new intervention for transferring patients that is capable of minimizing the nurses' perceived workload in clinical and non-clinical settings.IMPLICATIONS FOR REHABILITATION:The NEAR-1 motorized lifting device reduced perceived workload for nurses while handling and transferring patients between a bed and wheelchair.The nurses recorded a usability score of 76.86 for the NEAR-1, reflecting their positive perceptions towards the technology.The new device has the potential to reduce the physical stress on nurses and decrease the incidence of work-related musculoskeletal disorders.

Translaminar screw fixation of the cervical spine in Asian population: feasibility and safety consideration based on computerized tomographic measurements.

PURPOSE: Cervical translaminar screw fixation has been shown to be safe, efficient and provides alternative for cervical fixation. However, its use in the Asian population should be considered cautiously because the cervical lamina diameter may not be adequate to accommodate the standard lamina screw size. We studied the average transverse lamina diameter of the cervical spine in the Malaysian population to evaluate the feasibility and safety of lamina screw fixation in this population. METHODS: The measurements of the cervical lamina were performed on CT images. The diameters were defined as the most inner or outer diameter of the lamina, taken perpendicular to the axis of the lamina and measured in millimeters up to 0.1 mm. RESULTS: The mean transverse inner diameter of the lamina of C2, C3, C4, C5, C6 and C7 was 3.4, 2.0, 1.7, 1.9, 2.3 and 3.4 mm, respectively. The lamina of C2 and C7 has the largest transverse inner diameter and the lamina of C4 the smallest. The mean transverse outer diameter of the lamina of C2, C3, C4, C5, C6 and C7 was 5.6, 3.5, 3.1, 3.1, 3.9 and 5.8 mm, respectively. The lamina of C7 has the largest transverse outer diameter and the lamina of C4 and C5 the smallest. CONCLUSIONS: Translaminar fixation using a 3.5 screw should be attempted with caution in Asian population. Pre-operative CT scan evaluation is mandatory before translaminar screw fixation is attempted.

Determination of the Entry Point for Lower Lumbar Intradiscal Procedure Using Transforaminal Technique: Cross-Sectional Study Using Magnetic Resonance Imaging.

Introduction: Triangular working area otherwise known as the Kambin triangle is designated as a safe place to position the instrument during the operation, with minimal risk to exiting nerves. This study aims to improve understanding and increase the safety of various transforaminal intradiscal procedures at L3/L4, L4/L5, and L5/S1 levels. Methods: A cross-sectional analysis involving 102 MRIs that met the inclusion criteria was obtained and analyzed at the L3/L4, L4/L5, and L5/S1 discs level. For each level, the Kambin triangle was measured. By evaluating those measurements, the viability of this method was determined. Results: Safe working zone approach angles were consistently getting wider from L3 to S1 levels. It was statistically significant to be wider for the left side for the mean angle of lateral nucleus trajectory at the L4/L5 level and L5/S1. The entry point is at 32, 45, and 55-60 mm from the midline, and the instrument should be directed at 12°, 20°, and 27° medially for the lateral nucleus at L3/L4, L4/L5, and L5/S1, respectively. The center of the nucleus pulposus entry point is at 64, 77, and 85 mm from the midline with a medial inclination of 40°, 47°, and 52°, respectively, for L3/L4, L4/L5, and L5/S1. For the posterior nucleus pulposus, the skin should be pierced 90, 140, and 180 mm from the midline and directed medially at 53°, 61°, and 68°, respectively, for L3/L4, L4/L5, and L5/S1. The posterior annulus fibrosis entry point is 172, 355, and 450 mm with a medial inclination of 69°, 80°, and 84° at L3/L4, L4/L5, and L5/S1, respectively. The sagittal inclination is 3° cephalad at L3/L4, 10° caudally at L4/L5, and 27° caudally at L5/S1. Conclusions: Preoperative MRI assessment is important to determine the angle of trajectory for the safe entry point for intradiscal procedure via transforaminal approach.

Predicted cervical canal enlargement and effective cord decompression following expansive laminoplasty using cervical magnetic resonance imaging.

BACKGROUND: Posterior translation of the spinal cord occurs passively following laminoplasty with the presence lordotic spine and availability of a space for the spinal cord to shift. This study is to predict the distance of posterior spinal cord migration after expansive laminoplasty at different cervical levels based on measurement of posterior translation of the spinal cord in normal cervical morphometry. METHODS: Measurements were performed from C34, C45, C56 and C67 disc using magnetic resonance imaging (MRI) images. Apical level of the cervical curve, lordotic angle, spinal cord diameter, spinal canal diameter, space anterior to the cord and spinal canal/cord ratio were determined before and after postulated laminoplasty. Statistical analysis was performed to assess the significance of the canal enlargement and effective spinal cord decompression at each level. RESULTS: The predicted spinal canal decompression achieved at C34, C4C5, C56 and C67 levels were 48.8, 71.9, 84 and 86.5%, respectively. The mean measurement of spinal canal after laminoplasty was 16.7 mm with spinal canal diameter increased between 3.5 and 5.6 mm. Space anterior to the cord after laminoplasty increased to between 8.6 and 10.9 mm. There was significant correlation between Cobb's angle and spinal canal diameter post laminoplasty at C45, C56 and C67 but no significant correlation between Cobb's angle and space anterior to the cord post laminoplasty was found. CONCLUSIONS: Laminoplasty may produce larger canal expansion at the lower cervical spine compared to the upper cervical area; therefore, the outcomes of those who have predominantly higher cervical myelopathy were inferior to those who have lower cervical myelopathy.

Computed Tomographic Morphometric Analysis of C1 and C2 for Lamina Cross Screw Placement in Malay Ethnicity.

STUDY DESIGN: This is an observational study of computed tomography (CT) data. PURPOSE: The C1 and C2 laminas in the Malaysian Malay population were analyzed for the feasibility of fitting 3.5-mm laminar screws in a cross configuration. OVERVIEW OF LITERATURE: Morphometric analysis of the C1 and C2 laminas has been performed for various populations but not for the Malaysian Malay population. METHODS: A total of 330 CT cervical images were measured to establish the bicortical diameter of the C1 and C2 laminas as well as their height and length. The C1 posterior tubercle bicortical diameter and height were also determined from these images. All parameters were measured up to 0.1 mm, and statistical analysis was performed using IBM SPSS Statistics ver. 24.0 (IBM Corp., Armonk, NY, USA). An independent t -test and the Pearson chi-square test were used to determine the mean difference and screw acceptance. RESULTS: The means of the C1 lamina measurements were 5.79±1.19 mm in diameter, 9.76±1.51 mm in height, and 20.70±1.86 mm in length. The means of the measurements of the posterior tubercle were 7.20±1.88 mm in diameter and 10.51±1.68 mm in height. The means of the C2 lamina measurements were 5.74±1.31 mm in diameter, 11.76±1.69 mm in height, and 24.96±2.56 mm in length. Overall 65.5% of C1 and 80.3% of C2 laminas are able to accept 3.5-mm screws in a cross configuration. Screw acceptability is similar between the right and left sides (p >0.05). However, males have a higher screw acceptability compared with females (p <0.05), except for the C2 left lamina. CONCLUSIONS: It is feasible to insert a 3.5-mm screw in a cross configuration in the C1 and C2 laminas of the Malaysian Malay population, especially in males. However, a CT scan should be performed prior to the operation to determine screw acceptability and to estimate screw sizes.

Morphological comparison between adolescent and adult lumbar pedicles using computerised tomography scanning.

BACKGROUND: To study the morphological difference between the lumbar pedicle in adolescent and adult groups as only less information is known about their pedicle morphology, especially in Malaysian population. METHODS: The pedicle parameters of the lumbar spine in adolescent and adult groups including transverse outer pedicle diameter, transverse inner pedicle diameters, medial wall cortical thickness, lateral wall cortical thickness, pedicle length, transverse pedicle angle and sagittal pedicle angle were measured using computerised tomography (CT) scanning. The measurements in both groups were compared and analysed using statistical method. RESULTS: In adolescent group, the mean transverse outer diameter was 8.9 +/- 1.2 mm, transverse inner diameter was 6.3 +/- 1.2 mm, medial cortical thickness was 1.6 +/- 1.2 mm, lateral cortical thickness was 1.3 +/- 1.2 mm, pedicle length was 41.7 +/- 3.8 mm, transverse angle was 20.0 +/- 2.5 degrees and sagittal angle was 16.0 +/- 1.7 degrees . In adult group, the mean transverse outer diameter was 9.8 +/- 1.3 mm, transverse inner diameter was 7.0 +/- 1.2 mm, medial cortical thickness was 1.7 +/- 1.2 mm, lateral cortical thickness was 1.4 +/- 1.6 mm, pedicle length was 44.8 +/- 5.0 mm, transverse angle was 21.7 +/- 2.3 degrees and sagittal angle was 17.4 +/- 1.7 degrees . Comparing the mean of the two age groups, all the measurements were significantly smaller (p < 0.05) in the adolescent patients. CONCLUSIONS: Pedicle morphology in adolescent and adult population is different in all parameters, especially in males. Understanding of specific pedicle morphology for each group is imperative for safety in spinal procedures using pedicle route.

Feasibility of Unilateral Approach for Bilateral Decompressive Endoscopic Spinal Surgery for Lumbar Stenosis to Improve Back and Leg Pain: A Consecutive Single-Center Series of 60 Patients.

Introduction: Endoscopic surgery is one of the methods that achieve the goal of decompression while minimizing collateral tissue damage. Its efficacy and safety have been supported by numerous studies. There is a plethora of studies on lumbar stenosis regarding the outcomes and related issues in endoscopic spine surgery. However, few studies evaluated the outcome of the decompressive lumbar spine surgery. The present study aims to analyze the outcome of a unilateral approach to endoscopic surgery for lumbar stenosis using the visual analog scale (VAS), the Oswestry Disability Index (ODI), and MacNab's criteria. Methods: This is a retrospective study (level IV) conducted between January 2009 and December 2013 on 60 patients who underwent endoscopic interlaminar decompressive spine surgery (Destandau method) for lumbar degenerative spinal stenosis in the Hospital Universiti Sains Malaysia. The clinical outcome was measured pre-operatively and post-operatively for VAS: for back and leg pain, motor and sensory grading, the ODI, and MacNab's criteria. A paired t-test was used for statistical analysis. Results: The mean age of patients was 60.82 years comprising 23 males (38.3%) and 37 females (61.7%). The mean follow-up period was 30.1 months (range = 17.2-43 months). The mean operation time was 183.6 min (ranging from 124.8 to 242.4 min), and the mean blood loss was 150.18 mL (ranging from 30.82 to 269.54 mL). Post-operatively, mean hospital stay was 2.45 days (ranging from 1.34 to 3.56 days). The most frequently involved level was L4/L5 in 51 patients (52.6%), followed by L3/L4 in 19 patients (19.6%), L5/S1 in 24 patients (24.7%), and L2/L3 in three patients (3.1%). Improvement in the post-operative VAS for back and leg pain and the ODI for pre-operation and post-operation was statistically significant (p < 0.001). Conversely, the reduction in neurological status was statistically insignificant. Based on MacNab's criteria, 88.4% showed excellent to good outcomes. Conclusion: To summarize, unilateral percutaneous endoscopic spine surgery to achieve the bilateral decompression in lumbar stenosis provides excellent yet safe and effective outcomes. It improves back and leg pain and patients' function significantly.

Does Vertical Ground Reaction Force of the Hip, Knee, and Ankle Joints Change in Patients with Adolescent Idiopathic Scoliosis after Spinal Fusion?

STUDY DESIGN: Comparative cross-sectional study. PURPOSE: We measured the vertical ground reaction force (vGRF) of the hip, knee, and ankle joints during normal gait in normal patients, adolescent idiopathic scoliosis (AIS) patients with a Cobb angle <40° and in AIS patients with spinal fusion. We aimed to investigate whether vGRF in the aforementioned joints is altered in these three groups of patients. OVERVIEW OF LITERATURE: vGRF of the lower limb joints may be altered in these groups of patients. Although it is known that excessive force in the joints may induce early arthritis, there is limited relevant information in the literatures. METHODS: We measured vGRF of the hip, knee, and ankle joints during heel strike, early stance, mid stance, and toe-off phases in normal subjects (group 1, n=14), AIS patients with Cobb angle <40° (group 2, n=14), and AIS patients with spinal fusion (group 3, n=13) using a gait analysis platform. Fifteen auto-reflective tracking markers were attached to standard anatomical landmarks in both the lower limbs. The captured motion images were used to define the orientations of the body segments and force exerted on the force plate using computer software. Statistical analysis was performed using independent t-test and analysis of variance to examine differences between the right and left sides as well as those among the different subject groups. RESULTS: The measurements during the four gait phases in all the groups did not show any significant difference (p>0.05). In addition, no significant difference was found in the vGRF measurements of all the joints among the three groups (p>0.05). CONCLUSIONS: A Cobb angle <40° and spinal fusion did not significantly create imbalance or alter vGRF of the lower limb joints in AIS patients.

Osteoarticular and soft-tissue melioidosis in Malaysia: clinical characteristics and molecular typing of the causative agent.

INTRODUCTION: Melioidosis involving bone, joints, and soft tissue is rare and reported usually following dissemination of disease from infection elsewhere in the body; to a lesser degree, it can also be reported as the primary manifestation of melioidosis. METHODOLOGY: The orthopedic registry at Hospital University Sains Malaysia from 2008 until 2014 was retrospectively reviewed and was followed by molecular typing of Burkholderia pseudomallei. RESULTS: Out of 20 cases identified, 19 patients were confirmed to have osteoarticular and/or soft-tissue melioidosis. The majority of the patients were males (84%), and 16 patients had underlying diabetes mellitus with no significant estimated risk with the disease outcomes. Bacterial genotype was not associated with the disease as a risk. Death was a significant outcome in patients with bacteremic infections (p = 0.044). CONCLUSION: Patients with lung or skin melioidosis require careful treatment follow-up to minimize the chance for secondary osteoarticular infection. Human risk factors remain the leading predisposing factors for melioidosis. Early laboratory and clinical diagnosis and acute-phase treatment can decrease morbidity and mortality.

Relationship between pulmonary function and degree of spinal deformity, location of apical vertebrae and age among adolescent idiopathic scoliosis patients.

INTRODUCTION: This retrospective review aimed to examine the relationship between preoperative pulmonary function and the Cobb angle, location of apical vertebrae and age in adolescent idiopathic scoliosis (AIS). To our knowledge, there have been no detailed analyses of preoperative pulmonary function in relation to these three factors in AIS. METHODS: A total of 38 patients with thoracic or thoracolumbar scoliosis were included. Curvature of spinal deformity was measured using the Cobb method. Forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were used to evaluate preoperative pulmonary function. Statistical methods were used to analyse the relationship between preoperative pulmonary function and the factors that may contribute to poor pulmonary function. RESULTS: The mean age of the patients was 16.68 ± 6.04 years. An inverse relationship was found between the degree of the Cobb angle and FVC as well as FEV1; however, the relationships were not statistically significant (p = 0.057 and p = 0.072, respectively). There was also a trend towards a significant negative correlation between the thoracic curve and FVC (p = 0.014). Patients with larger thoracic curves had lower pulmonary function. A one-year increase in age significantly decreased FVC by 1.092 units (p = 0.044). No significant relationship between age and preoperative FEV1 was found. The median FVC was significantly higher in patients with affected apical vertebrae located at levels L1-L3 than at T6-T8 or T9-T12 (p = 0.006). CONCLUSION: Lung function impairment was seen in more severe spinal deformities, proximally-located curvature and older patients.

Reduced nitric oxide-mediated relaxation and endothelial nitric oxide synthase expression in the tail arteries of streptozotocin-induced diabetic rats.

Diabetes is associated with endothelial dysfunction, which is characterized by impaired endothelium-dependent relaxations. The present study aimed to examine the role of nitric oxide (NO), prostacyclin and endothelium-dependent hyperpolarization (EDH), in the relaxation of ventral tail arteries of rats under diabetic conditions. Relaxations of tail arteries of control and diabetic rats were studied in wire myograph. Western blotting and immunostaining were used to determine the presence of proteins. Acetylcholine-induced relaxations were significantly smaller in arteries of diabetic compared to control rats (Rmax; 70.81 ± 2.48% versus 85.05 ± 3.15%). Incubation with the combination of non-selective cyclooxygenase (COX) inhibitor, indomethacin and potassium channel blockers, TRAM 34 and UCL 1684, demonstrated that NO-mediated relaxation was attenuated significantly in diabetic compared to control rats (Rmax; 48.47 ± 5.84% versus 68.39 ± 6.34%). EDH-type (in the presence of indomethacin and NO synthase inhibitor, LNAME) and prostacyclin-mediated (in the presence of LNAME plus TRAM 34 and UCL 1684) relaxations were not significantly reduced in arteries of diabetic compared to control rats [Rmax: (EDH; 17.81 ± 6.74% versus 34.16 ± 4.59%) (prostacyclin; 15.85 ± 3.27% versus 17.23 ± 3.75%)]. Endothelium-independent relaxations to sodium nitroprusside, salbutamol and prostacyclin were comparable in the two types of preparations. Western blotting and immunostaining indicated that diabetes diminished the expression of endothelial NO synthase (eNOS), while increasing those of COX-1 and COX-2. Thus, since acetylcholine-induced NO-mediated relaxation was impaired in diabetes because of reduced eNOS protein expression, pharmacological intervention improving NO bioavailability could be useful in the management of diabetic endothelial dysfunction.

Actinomycosis of the knee.

We report a case of actinomycosis presenting as a knee swelling in a 34 year-old man. Knee actinomycosis poses a diagnosis challenge to clinicians as it is rare, often mimics knee tuberculosis and culture of the causative microbes is technically difficult. The classic microscopic appearance of this Gram-positive bacteria often forms the basis of diagnosis.

The morphometric study of l3-L4 and L4-L5 lumbar spine in Asian population using magnetic resonance imaging: feasibility analysis for transpsoas lumbar interbody fusion.

STUDY DESIGN: Cross-sectional study on the measurement of relevant magnetic resonance imaging parameters in 100 patients presented for lumbar spine assessment. OBJECTIVE: To determine anatomical position of lumbar plexus and major blood vessels in relation to vertebral body and anterior edge of psoas muscle at L3-L4 and L4-L5 and to define the safe working zone for transpsoas approach for lumbar fusion. SUMMARY OF BACKGROUND DATA: Lateral transpsoas lumbar interbody fusion has been shown to be safe and provides alternative for lumbar fusion. However, proximity of neurovascular structures may not allow a safe passage for this procedure in the Asian population. METHODS: Relevant parameters were measured from axial magnetic resonance images and analyzed, including the psoas muscle and vertebrae endplate diameters, lumbar plexus and psoas muscle distance, lumbar plexus and vertebra body distance, and vena cava to the anterior vertebrae body diameters. RESULTS: The mean anteroposterior diameters of the right and left psoas muscle ranged from 44.0 to 58.6 mm and 44.8 to 54.0 mm, respectively. The mean anteroposterior diameters of vertebra endplate of L3, L4, and L5 were 38.2 mm, 39.3 mm, and 41.4 mm, respectively. The mean distance of posterior border of vena cava from the vertebra body was 4.5 mm at L3-L4 and 14.1 mm at L4-L5. CONCLUSION: L3-L4 fusion is feasible at both sides in both sexes; however, at L4-L5 level, the procedure is feasible only on the left side. The safe working zone for transpsoas approach to lumbar spine is significantly narrower at L4-L5 in both sexes. Anterior edge of psoas muscle can be used as a reliable guide to locate lumbar plexus within psoas muscle. LEVEL OF EVIDENCE: N/A.

Topology optimisation of spinal interbody cage for reducing stress shielding effect.

The stress shielding effect is an event in which the replacement implant limits the load transferred to bone and the ineffective stress in the vertebrae causes bony growth to cease. In the present study, a 3D finite element L4-L5 model was developed and subjected to a 1200 N compression preload. Five groups of muscle forces were applied on L4 under flexion-extension, lateral bending and axial rotation. Topology optimisation was employed for reducing the stress shielding effect by removing the ineffective material from the design domain. The optimised design was designed with polyaryletheretherketone (PEEK) titanium and cortical materials to encounter the shielding response. The stress responses show that the new design increased the stress magnitude by at least 17.10, 18.11 and 18.43% in 4 Nm of flexion-extension, lateral bending and axial rotation, respectively. In conclusion, the material factor did not significantly alter the stress magnitude, but volume was the key factor in reducing the stress shielding effect.

Computed tomographic morphometry of thoracic pedicles: safety margin of transpedicular screw fixation in malaysian malay population.

STUDY DESIGN: A cross-sectional study of thoracic pedicle morphometry (T1-T12) of 180 Malaysian Malay patients obtained from computed tomographic scan. OBJECTIVES: To determine the safety margin in the placement of thoracic transpedicular screw in the Malay population. SUMMARY OF THE BACKGROUND DATA: Previous studies have shown a significantly smaller thoracic pedicular parameters in Asians compared with whites. The safety margin in the placement of thoracic transpedicular screw in our population therefore needs to be defined. METHODS: T1-T12 vertebral pedicles were studied in 180 Malay ethnic patients (age range, 18-80 years). The following parameters were studied: transverse outer pedicle diameter, transverse inner pedicle diameter, transverse pedicle angle, chord length, pedicle length, and pedicle cortical thickness. The data obtained were statistically analyzed using Student's t test and ANOVA test. RESULTS: Female patients have significantly smaller dimensions in most of the parameters measured compared with male patients. However, no significant difference was found between age groups. Transverse outer pedicle diameter were widest at T1 (male, 8.42 mm; female, 7.56 mm) and narrowest at T4 (male, 4.56 mm; female, 3.95 mm). Pedicle diameters of less than 5.5 mm were commonly seen at T4 followed by T5, T6, T7, T8, and T9. A significant percentage of patients have an outer diameter of less than 4.5 mm from T4-T7. The medial cortices were 50% thicker than the lateral cortices at most levels. Chord lengths were maximum at T8 and minimum at T1. Transverse pedicle angle were widest at T1 and less than 5 degrees from T7-T12. CONCLUSIONS: The results suggest that the current pedicle screw system is not suitable for the majority of Malay population, especially at midthoracic level. The smaller pedicle measurements in Malays may be attributed to their shorter body built compared with whites.

Computerized tomographic measurement of the cervical pedicles diameter in a Malaysian population and the feasibility for transpedicular fixation.

STUDY DESIGN: The cervical pedicle diameter size differs between Asians and non-Asians. The authors studied the transverse pedicle diameter of the C2-C7 of the cervical spine in a Malaysian population using computerized tomography (CT) measurements. The transverse diameter of the pedicle is the determinant of the feasibility of this technique because the sagittal diameter of the pedicle has been wider than the transverse pedicle diameter. OBJECTIVES: To study the average transverse pedicle diameter of the cervical spine in a Malaysian population, and evaluate the feasibility and safety of pedicle screw fixation in these patients. SUMMARY OF BACKGROUND DATA: Cervical transpedicular screw fixation has been safe and is most probably going to be the gold standard for cervical spine fixation. However, its use in the Asian population should be considered cautiously because our cervical pedicle diameter may not be adequate to accommodate the standard pedicle screw size, which can be dangerous because there are vital structures located adjacent to the pedicles. METHODS: The measurements of the cervical pedicles were performed on CT images using its measurement tools. CT cutting was made at 2.5-mm intervals. The pedicle transverse diameters were defined as the most outer diameter of the pedicle, taken perpendicular to the axis of the pedicle and measured in millimeters up to 0.1 mm. RESULTS: The mean transverse diameters of the cervical pedicle of C2, C3, C4, C5, C6, and C7 in males were 5.4, 5.2, 5.1, 5.2, 5.5, and 6.5 mm, respectively, and ranged between 5.1 and 6.5 mm. In females, the mean transverse diameter of the cervical pedicle of C2, C3, C4, C5, C6, and C7 were 5.0, 4.6, 4.7, 4.9, 5.2, and 5.6 mm, respectively, and ranged between 4.6 and 5.6 mm. If the minimum transverse diameter required is 5.0 mm for 3.5-mm screw insertion, about 4.2% to 54.2% (male) of pedicles at different levels and 6.7% to 73.3% (females) of patients cannot have fixation with a 3.5-mm screw using this technique. CONCLUSION: Transpedicular screw fixation for the cervical spine must not be attempted in the Malaysian population before the exact pedicle diameters are known.Therefore, preoperative CT evaluation is a must before transpedicular fixation is performed, especially in female patients. Because the margin for mistake is very narrow, it is best avoided in upper cervical spines.