Chulalongkorn Medical Journal


Problem : The incidence of complications in cervical disc arthroplasty was6.2% per treat level. Perioperative kyphosis, heterotopic ossificationand migration may occur be due to undersized prosthesis.Measurement of the dimensions of cervical discs of the Thaipopulation was aimed to be a pilot study to know the estimationof the dimensions of cervical discs that could be referred tothe size of disc prosthesis devices.Objective : To provide data regarding the diamension of cervical discsdimensions that can be used in Thailand for preoperative planningand design of cervical disc prosthesis in Thailand.Study design : Descriptive study.Setting : Department of Orthopedics, King Chulalongkorn Memorial Hospital.Method and Material : From January 2008 to December 2008, 60 consecutive C-spinemagnetic resonance imaging studies were performed on Thaisubjects. MRI was performed using a 1.5 Tesla whole body MRimaging system with an extremity coil. Pulse sequences wereT2-weighted images. The direction of the axial slice imaging placedthe slice perpendicular to the spinal mechanical axis in the coronalplane and perpendicular to the long axis of the spine in the sagittalplane. All 60 images were reconstructed at 3-mm intervals.Result : Total mean maximum disc height in Thai population are as follows:C3-4 6.44 mm, C4 - 5 5.90 mm, C5 - 6 5.79 mm, C6 - 7 6.28 mmand C7 - T1 6.21 mm. The differences in the maximum disc heightsbetween males and females were significant. The maximum andminimum distances from all samples are 6.63 mm and 5.47 mm,respectively. The total mean sagittal diameter in the Thai populationare: C3i 14.77 mm, C4s 14.77 mm, C4i 15.23 mm, C5s 15.13 mm,C5i 15.74 mm, C6s 15.62 mm, C6i 15.72 mm, C7s 15.69 mm, C7i15.79 mm and T1s 16.00 mm. The maximum and minimum distancesfrom all samples are 16.47 mm and 13.33 mm respectively.The differences in maximum disc height between males andfemales were significant. The total mean transverse diameters inthe Thai population are C3i 21.77 mm, C4s 22.15 mm, C4i 22.15mm, C5s 22.95 mm, C5i 23.44 mm, C6s 24.23 mm, C6i 25.36 mm,C7s 26.28 mm, C7i 26.92 mm and T1s 26.95 mm. The maximumand minimum distances from all samples are 27.73 mm and 20.80mm respectively. The differences in the maximum disc heightbetween males and females were significant.Conclusion : Measurement of disc dimensions can refer to the ranges of size tomanufacturers for the devices to cover the use in Thai patients.The data fulfill the goal described for cervical disc dimension forthe Thai population. The results of the project could provide designand data for the manufacturers and next step of experiment forcervical disc prosthesis suitable for the Thai population.


Faculty of Medicine, Chulalongkorn University

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