| Background:In recent years, transpedicular placement or insertion surgical method is widely used in percutaneous vertebroplasty(PVP), spine Fracture, scoliosis, and so forth. The width of Upper thoracic veterbra pedicle is short, and the relationship between thoracic pedicle inner cortex and dura mater is tight and no space at all, so the possibility of thoracic transpedicular placement penetrating the bone cortex is large. And paralysis is the most serious complication. Furthermore, X-ray's anteroposterior and lateral projection cannot satisfy the real requirements. Anteroposterior image was blocked by clavicle, ribs, mesosternum and lung and lateral by shoulder, so it's difficult to observe the images clearly. Upper thoracic spine of T1-T3 transpedicular placement or insertion is a great challenge.The current method of upper thoracic T1-T3 transpedicular placement or insertion is depending on CASNS or by hand. Due to anatomic marker and the doctors'experience, it is reported that the failure rate of transpedicular placement is 6%-41% because of lacking of effective monitoring. The CASNS can significantly improve the accuracy of transpedicular placement of lumbar spine, but has many disadvantages. Furthermore, it is reported that CASNS can't improve the accuracy rate of the upper thoracic spine of T1-T3.So it is meaningful to explore a novel method for improving the accuracy and safety of thoracic transpedicular placement, and it is a critical issue to be solved.Method:1. According to the data measured on CT scanning, the distance a and angle a of the two guide wires of the manipulator were set, and its needlepoint locating at the two pedicle central axis(PCA) entry points (EP)were confirmed through trajectory matching(b,b') and the anteroposterior fluoroscopy.2. Register external "十"and internal "十"coincide with each other.3. After the two central axis of guide wire and central view axis of C-Arm were coincided respectively, the pedicle axis view was acquired via C-arm, the external "十"is adjusted to register with the internal"十", then the centre of pedicle isthmus(CPI) is confirmed. EP and CPI making a line is the pedicle central axis(PCA).4. The insertion along the PC A was achieved by the robot's guide wire under monitoring.5. The deviation between post/preoperative TSA, SSA was analyzed by statistic method respectively. And the excursion of the medical/lateral and superior /inferior shortest distance from EP to the planned was done similarly.Results:1. All the specimens,36 pedicle centre axis view was acquired and the accuracy of the inserting trajectory is 100%.The guide-wire trajectory was supervised and right in the middle of the lateral and axis image.2. On postoperative CT scanning images, the deviation distance between the medical/lateral and superior/inferior shortest distance from EP to the planned was 0.09±0.29mm (p=0.058) and 0.01±0.31mm (p=0.874) seperatively.3. Preoperation TSA measurement from T1to T3 were32.1±3.2°; 20.2±3.3°; 14.1±3.6°. Postoperation TSA measurement from T1 to T3 were 32.4±3.3°,19.9±3.3°,14.6±3.8°。There were no statistic difference between them (p>0.05).4. Preoperation SSA measurement from T1 to T3 were 11.2±2.7°;10.9±3.5°; 9.8±2.6°. Postoperation TSA measurement from T1 to T3 were 11.5±3.0°; 11.3±3.3°; 9.9±2.3°. There were no statistic difference between them(p> 0.05).conclusion:The spine navigation surgery robot can confirm the thoracic spine of T1-T3 EP accurately. And combined with the internal and the external"十" registration, the robot can insert along the PCA or the planned trajectory accurately, which provides a novel and efficient method of improving the accuracy for the upper thoracic spine of T1-T3. |
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