ABSTRACT
Objective To explore the orientation relationships and changing rules of pedicle screw entry point (PSEP) on the posterior bony landmarks in middle-upper thoracic vertebrae in adults by measuring parameters of 3-D reconstruction CT images. Methods CT images of the middle-upper thoracic vertebrae from 30 healthy adults were used for 3-D reconstruction to observe the anatomical characteristics of posterior bony landmarks, including transverse process-lamina concave, superior ridge of transverse process and outer edge of the lamina. The following basic parameters, including PSEP-to-midline distance (PMD), transverse process-lamina concave-to-midline distance (CMD) and half lamina width (HLW), and target parameters, including PSEP-to-transverse process-lamina concave distance (PCD), entry point location ratio (EPLR) and PSEP-to-superior ridge of transverse process distance (PRD) were determined on reconstructed CT images from T1 to T10. The differences of bilateral measurements of all parameters and the differences of basic parameters were analyzed, and the changing rules of target parameters measurements from T1 to T10 were summarized. Results The transverse process-lamina concave, superior ridge of transverse process and outer edge of the lamina of middle-upper thoracic vertebral characterized by obvious and constant anatomical marks with less proliferative. The left and right PMD, CMD, HLW, PCD, EPLR, and PRD were (14.14±2.63) mm and (14.59±2.58) mm, (10.45±2.12) mm and (10.51±2.02) mm, (16.30±1.48) mm and (16.39±1.61) mm, (4.56±1.03) mm and (4.47±0.94) mm, 0.35±0.26 and 0.33±0.30, and (-1.62±1.90) mm and (-1.63±1.44) mm, respectively. There was no significant difference in the measured values between the two sides of the above parameters (P>0.05). Except that the difference between PMD and HLW in T2 was not significant (P>0.05), the differences between basic parameters in the other segments were statistically significant (P<0.05). PCD of T1 to T10 showed a trend of decrease first and then significant increases in T1, T2, T9, and T10 compared with in T3-T8 (P<0.05). EPLR of T1-T10 showed a trend of increase first and then decrease, in which EPLR in T1, T2 and T3 were significantly lower than in the following any segments (P<0.01), and in the T4-T6 and T10 were significantly lower than in T7-T9 (P<0.01). PRD of T1-T10 showed a trend of increase first and then decrease, in which the PRD in T1, T2 and T3 were significantly lower than in the following any segments, and in the T4-T6 were lower than T7-T10 (P<0.01). Conclusion There is constant orientation relationship and changing rules of PSEP in the middle-upper thoracic vertebrae on the posterior bony landmarks, such as transverse process-lamina concave, superior ridge of transverse process and outer edge of the lamina, and it can serve as a new clinical choice.
ABSTRACT
Objectives: To verify the feasibility and safety of the anterior transpedicular screw(ATPS) fixation of the upper thoracic spine (T1-T4) through the radiological anatomy study on the cadaveric specimens. Methods: The upper thoracic spine thin-section CT data of 40 cases were collected from the radiology de-partment′s database(20 males and 20 females, aged from 18 to 68 years, the mean age was 39.7 years). The data of OPW(outer pedicle width), OPH(outer pedicle height), PAL(pedicle axis length), TPA(transverse section angle), SPA(sagittal section angle), DTIP(distance of transverse intersection point) and DSIP(distance of sagittal intersection point) of each pedicle were measured on the transverse and sagittal sections through the axis of each pedicle. The data were recorded and statistically analyzed. 10 upper thoracic spine(C7-T6) specimens of adults(5 males and 5 females, with unknown ages), with no damage to their appearance, the costovertebral joints and paravertebral soft tissue were completely retained. Then simulate surgical operations were done on the cadaveric specimens based on the obtained data. Screws were implanted anteriorly by free hand. After that, the specimens accepted X-ray fluoroscopy and CT scan. At last, the screws were removed, the speci-mens were sawed along the transaction and sagittal section of the screw channel. Then the success rate of the screw placement was evaluated according to Rao′s worn out classification standard of pedicle screws. Results: From T1 to T4, the OPW decreased from 8.14mm to 3.47mm; the OPH increased from 6.89mm to 10.29mm; the TPA decreased from 32.96° to 11.64°; the DTIP increased from 1.80mm to 5.50mm; the SPA increased from 104.95° to 115.74°; the DSIP increased from 5.95 to 8.76mm; the PAL changed irregularly, from 32.95 to 35.96mm. The pedicle diameters of T3 and T4 were too small to implant ATPS, but the ARTPS can be implanted successfully. The diameter of ATPS was about 4.0mm; the length of ATPS was about 35mm. The diameter of ARTPS was about 5.0mm; the length of ARTPS was about 35mm. 80 pedicle screws were implanted anteriorly, according to Rao′s worn out classification standard of pedicle screws, the fine rate was 90%. The internal walls of 7 pedicles were broken by screws of less than 2mm and no compression to the spinal cord. The internal walls of 5 pedicles were broken of 2 to 4mm, 1 at T1, 1 at T3 and 3 at T4, with varying degrees of spinal cord compression. The internal walls of 2 pedicles were broken of greater than 4mm, 1 at T2 and 1 at T4, with serious spinal cord compression. The external wall of 1 pedicle was broken at T2. Conclusions: The ATPS techniques at T1, T2 and the ARTPS techniques at T3, T4 are feasible, but the safety and clinical practice and further research is needed.
ABSTRACT
[Objective] To investigate the anatomical relation between manubrium sternum incisure(MSI)with the level of upper thoracic vertebrae(UTV)and to find out the basis of operative approach of UTV.[Method]Standing pan chest radiographs of 400 male and 400 female were equally divided into 4 year groups:≤19 years,20～39 years,40～59 years and ≥60 years and were used to observe the relationship between MSI with the level of UTV.On the basis of this relationship,a suitable UTV approach was advocated.There were fracture and dislocation of UTV 7 cases,UTV tumor 9 cases,tuberculosis of UTV 3 cases;OPLL ossification of UTV 2 cases.Diseases located at T1 6 cases,T2 7 cases,T3 2 cases,T4 3 cases,T1、2 2 cases,T2、3 1 case.Lower anterior cervical approach was performed for 7 cases including T1、2 one case and T2 one case,improved T3 1 case,and right subscapular transthoracic posterolateral approach was used for 5 cases.[Result]The number of UTV in relationship with the level of MSI was successively increased from T1 to T3 and was gradually decreased on T4,i.e.rate of cases of level of MST in relationship with T1、2 level was 1%,to T2 level 5.5%,to T2、3 level 15.87%,to T3 level 43.5%,to T3、4 level 20.75%,to T4 13.375%.No relationship was found in trend of distribution with the age and gender.The operative approach of UTV according its relationship with MSI was performed with the advantages of satisfactory exposure easily manipulation and satisfactory clinic results in most follow-up cases.One case died of metastasis of tumor in 9 months,3 cases were complicated with cerebrospinal fluid leakage and 3 cases with injury of recurrent laryngeal nerve.[Conclusion]Approach to UTV should be selected according to its relationship between MSI and diseased UTV preoperatively.The operative approach of UTV according to its relationship with MST has the advantages of satisfactory exposure,easily manipulation and satisfactory clinic results.
ABSTRACT
Bone and joint involement develops in approximately 10 percent of patients with tuberculosis and half of these affected patients have tuterculosis of the spine. The goals of management are to eradicate the infection and to prevent or treat neurologic deficits and spinal deformity. An operation may be performed to drain abscess, to debride sequestered bone and disc, to decompress the spinal cord, or to stabilize the spine for the prevention of correction of deformity. But there are difficulties in approaching the upper thoracic spine(T1-T3). These vertebral bodies can be visualize through a standard thoracotomy. Access is greatly restricted, however, by the scapula and the remaining rabs, making a vertebrectomy and spinal cord decompression very difficult. Reconstruction of the vertebral defect and instrumentation to give spinal stability are equally difficult. We describe a surgical approach to the upper thoracic spine which allow an adequate exposure of the vertebral bodies from T1 to T3. The posterolateral thoracotomy approach seems to be a safe and useful method for the upper thoracic lesion, allows adequate exposure exposure and easy reconstruction.