Translaminar screw fixation in the upper thoracic spine

2006 ◽  
Vol 5 (6) ◽  
pp. 527-533 ◽  
Author(s):  
Ryan M. Kretzer ◽  
Daniel M. Sciubba ◽  
Carlos A. Bagley ◽  
Jean-Paul Wolinsky ◽  
Ziya L. Gokaslan ◽  
...  

Object The use of pedicle screws (PSs) for instrument-assisted fusion in the cervical and thoracic spine has increased in recent years, allowing smaller constructs with improved biomechanical stability and repositioning possibilities. In the smaller pedicles of the upper thoracic spine, the placement of PSs can be challenging and may increase the risk of damage to neural structures. As an alternative to PSs, translaminar screws can provide spinal stability, and they may be used when pedicular anatomy precludes successful placement of PSs. The authors describe the technique of translaminar screw placement in the T-1 and T-2 vertebrae. Methods Seven patients underwent cervicothoracic fusion to treat trauma, neoplasm, or degenerative disease. Nineteen translaminar screws were placed, 13 at T-1 and six at T-2. A single asymptomatic T-2 screw violated the ventral laminar cortex and was removed. The mean clinical and radiographic follow up exceeded 14 months, at which time there were no cases of screw pull-out, screw fracture, or progressive kyphotic deformity. Conclusions Rigid fixation with translaminar screws offers an attractive alternative to PS fixation, allowing the creation of sound spinal constructs and minimizing potential neurological morbidity. Their use requires intact posterior elements, and care should be taken to avoid violation of the ventral laminar wall.

2010 ◽  
Vol 66 (suppl_1) ◽  
pp. ons-178-ons-182
Author(s):  
Andrew S. Little ◽  
Leonardo B.C. Brasiliense ◽  
Bruno C.R. Lazaro ◽  
Phillip M. Reyes ◽  
Curtis A. Dickman ◽  
...  

Abstract Objective: To compare the biomechanics of costotransverse process screw fixation with those of pedicle screw fixation in a cadaveric model of the upper thoracic spine. Methods: Ten human thoracic spines were instrumented across the T3–T4 segment with costotransverse and pedicle screws. Nonconstraining pure moments (maximum, 6.0 Nm) were applied to induce flexion, extension, lateral bending, and axial rotation. The range of motion, lax zone, and stiff zone were determined in each specimen in the normal state, after 3-column destabilization, and after instrumentation. After flexibility testing was completed, axial screw pull-out strength was assessed. Results: In all directions of loading, both fixation techniques significantly decreased lax zone and range of motion at T3–T4 compared with the destabilized state (P < .001). During all loading modes except lateral bending, pedicle screw fixation allowed significantly less range of motion than costotransverse screw fixation. Pedicle screws provided 62% greater resistance to axial pull-out than costotransverse screws. Conclusion: The costotransverse screw technique seems to provide only moderately stiff fixation of the destabilized thoracic spine. Pedicle screw fixation seems to have more favorable biomechanical properties. These data suggest that the costotransverse process construct is better used as a salvage procedure rather than as a primary fixation strategy.


2010 ◽  
Vol 12 (3) ◽  
pp. 286-292 ◽  
Author(s):  
Ryan M. Kretzer ◽  
Christopher Chaput ◽  
Daniel M. Sciubba ◽  
Ira M. Garonzik ◽  
George I. Jallo ◽  
...  

Object Translaminar screws (TLSs) offer an alternative to pedicle screw (PS) fixation in the upper thoracic spine. Although cadaveric studies have described the anatomy of the laminae and pedicles at T1–2, CT imaging is the modality of choice for presurgical planning. In this study, the goal was to determine the diameter, maximal screw length, and optimal screw trajectory for TLS placement at T1–2, and to compare this information to PS placement in the upper thoracic spine as determined by CT evaluation. Methods One hundred patients (50 men and 50 women), whose average age was 41.7 ± 19.6 years, were selected by retrospective review of a trauma registry database over a 6-month period. Patients were included in the study if they were over the age of 18, had standardized axial bone-window CT imaging at T1–2, and had no evidence of spinal trauma. For each lamina and pedicle, width (outer cortical and cancellous), maximal screw length, and optimal screw trajectory were measured using eFilm Lite software. Statistical analysis was performed using the Student t-test. Results The T-1 lamina was estimated to accommodate, on average, a 5.8-mm longer screw than the T-2 lamina (p < 0.001). At T-1, the maximal TLS length was similar to PS length (TLS: 33.4 ± 3.6 mm, PS: 33.9 ± 3.3 mm [p = 0.148]), whereas at T-2, the maximal PS length was significantly greater than the TLS length (TLS: 27.6 ± 3.1 mm, PS: 35.3 ± 3.5 mm [p < 0.001]). When the lamina outer cortical and cancellous width was compared between T-1 and T-2, the lamina at T-2 was, on average, 0.3 mm wider than at T-1 (p = 0.007 and p = 0.003, respectively). In comparison with the corresponding pedicle, the mean outer cortical pedicle width at T-1 was wider than the lamina by an average of 1.0 mm (lamina: 6.6 ± 1.1 mm, pedicle: 7.6 ± 1.3 mm [p < 0.001]). At T-2, however, outer cortical lamina width was wider than the corresponding pedicle by an average of 0.6 mm (lamina: 6.9 ± 1.1 mm, pedicle: 6.3 ± 1.2 mm [p < 0.001]). At T-1, 97.5% of laminae measured could accept a 4.0-mm screw with 1.0 mm of clearance, compared with 99.5% of T-1 pedicles; whereas at T-2, 99% of laminae met this requirement, compared with 94.5% of pedicles. The ideal screw trajectory was also measured (T-1: 49.2 ± 3.7° for TLS and 32.8 ± 3.8° for PS; T-2: 51.1 ± 3.5° for TLS and 20.5 ± 4.4° for PS). Conclusions Based on CT evaluation, there are no anatomical limitations to the placement of TLSs compared with PSs at T1–2. Differences were noted, however, in lamina length and width between T-1 and T-2 that must be considered when placing TLS at these levels.


2014 ◽  
Vol 05 (04) ◽  
pp. 349-354 ◽  
Author(s):  
Mark A. Rivkin ◽  
Jessica F. Okun ◽  
Steven S. Yocom

ABSTRACT Summary of Background Data: Multilevel posterior cervical instrumented fusions are becoming more prevalent in current practice. Biomechanical characteristics of the cervicothoracic junction may necessitate extending the construct to upper thoracic segments. However, fixation in upper thoracic spine can be technically demanding owing to transitional anatomy while suboptimal placement facilitates vascular and neurologic complications. Thoracic instrumentation methods include free-hand, fluoroscopic guidance, and CT-based image guidance. However, fluoroscopy of upper thoracic spine is challenging secondary to vertebral geometry and patient positioning, while image-guided systems present substantial financial commitment and are not readily available at most centers. Additionally, imaging modalities increase radiation exposure to the patient and surgeon while potentially lengthening surgical time. Materials and Methods: Retrospective review of 44 consecutive patients undergoing a cervicothoracic fusion by a single surgeon using the novel free-hand T1 pedicle screw technique between June 2009 and November 2012. A starting point medial and cephalad to classic entry as well as new trajectory were utilized. No imaging modalities were employed during screw insertion. Postoperative CT scans were obtained on day 1. Screw accuracy was independently evaluated according to the Heary classification. Results: In total, 87 pedicle screws placed were at T1. Grade 1 placement occurred in 72 (82.8%) screws, Grade 2 in 4 (4.6%) screws and Grade 3 in 9 (10.3%) screws. All Grade 2 and 3 breaches were <2 mm except one Grade 3 screw breaching 2-4 mm laterally. Only two screws (2.3%) were noted to be Grade 4, both breaching medially by less than 2 mm. No new neurological deficits or returns to operating room took place postoperatively. Conclusions: This modification of the traditional starting point and trajectory at T1 is safe and effective. It attenuates additional bone removal or imaging modalities while maintaining a high rate of successful screw placement compared to historical controls.


2009 ◽  
Vol 65 (suppl_6) ◽  
pp. ons167-ons172 ◽  
Author(s):  
Matthew J. McGirt ◽  
Edward G. Sutter ◽  
Risheng Xu ◽  
Daniel M. Sciubba ◽  
Jean-Paul Wolinsky ◽  
...  

Abstract Objective: The first in vitro biomechanical investigation comparing the immediate and postcyclical rigidities of thoracic translaminar versus pedicle screws in posterior constructs crossing the cervicothoracic junction (CTJ). Methods: Ten human cadaveric spines underwent C4–C6 lateral mass screw and T1–T2 translaminar (n = 5) versus pedicle (n = 5) screw fixation. Spines were then potted in polymethylmethacrylate bone cement and placed on a materials testing machine. Rotation about the axis of bending was measured using passive retroreflective markers and infrared motion capture cameras. The motion of C6 relative to T2 in flexion-extension and lateral bending was assessed uninstrumented, immediately after instrumentation, and after 40,000 cycles of 4 N•m flexion-extension and lateral bending moments at 1 Hz. The effect of instrumentation and cyclical loading on rotational motion across the CTJ was analyzed for significance. Results: Compared with preinstrumented spines, pedicle and translaminar screw constructs significantly (P &lt; 0.001) decreased motion during flexion-extension and lateral bending. After cyclical loading, rotational motion at the CTJ was significantly increased (P &lt; 0.05) during flexion-extension and lateral bending in both groups. With flexion-extension, the mean rotational motion across the CTJ was similar in the translaminar and pedicle constructs immediately after fixation, but slightly greater (P = 0.03) after cyclical loading in the translaminar versus the pedicle screw constructs (0.39 degrees versus 0.26 degrees). Nevertheless, after cyclical loading, the mean angular motion across the CTJ remained less than one half of a degree in both groups. With lateral bending, the mean rotational motion was similar in both translaminar and pedicle screw constructs. Conclusion: Both upper thoracic translaminar and pedicle screws allow for rigid fixation at the CTJ. Although translaminar screw constructs demonstrated one eighth of a degree more motion at the CTJ after cycling, this minimal difference is likely less than would influence the biological fusion process. Upper thoracic translaminar screws are a biomechanically effective option to rigidly stabilize the CTJ.


2011 ◽  
Vol 14 (3) ◽  
pp. 372-376 ◽  
Author(s):  
Mohammed Eleraky ◽  
Ioannis Papanastassiou ◽  
Matthias Setzer ◽  
Ali A. Baaj ◽  
Nam D. Tran ◽  
...  

Object Balloon kyphoplasty has recently been shown to be effective in providing rapid pain relief and enhancing health-related quality of life in patients with metastatic spinal tumors. When performed to treat lesions of the upper thoracic spine, kyphoplasty poses certain technical challenges because of the smaller size of the pedicle and vertebral bodies. Fluoroscopic visualization is also difficult due to interference of the shoulder. The authors' objective in the present study was to evaluate their approach and the results of balloon kyphoplasty in the upper thoracic spine in patients with metastatic spinal disease. Methods Fourteen patients underwent kyphoplasty via an extrapedicular approach to treat metastatic tumors in the upper (T1–5) thoracic spine. Electrodiagnostic monitoring (somatosensory and motor evoked potentials) was used in 5 cases. Three levels were treated in 7 cases, 2 levels in 2 cases, and 1 level in 5 cases. In 3 cases access was bilateral, whereas in 11 cases access was unilateral. The procedure took an average of 25 minutes per treated level, and the mean amount of cement applied was 3 ml per level. Four patients were discharged from the hospital on the day of the procedure, and 10 patients went home after 24 hours. Results All patients exhibited marked improvement in mean visual analog scale scores (preoperative score 79 vs postoperative score 30, respectively) and Oswestry Disability Index scores (83 vs 33, respectively). The mean kyphotic angle was 25.03° preoperatively, whereas the mean postoperative angle was 22.65° (p > 0.3). At latest follow-up, the mean kyphotic angle did not differ significantly from the postoperative kyphotic angle (26.3°, p > 0.1). No neurological deficits or lung-related complications (pneumothorax or hemothorax) were encountered in any of the patients. Polymethylmethacrylate cement extravasations were observed in 3 (10%) of 30 treated vertebral bodies without any sequelae. By a mean follow-up of 16 months, no patients had experienced an adjacent-level fracture. Conclusions Balloon kyphoplasty of the upper thoracic spine via an extrapedicular approach is an efficient and safe minimally invasive procedure that may provide immediate and long-term pain relief and improvement in functional ability. It is technically challenging and has the potential for serious complications. With a fundamental knowledge of anatomy, as well as an ability to interpret fluoroscopy images, one can feasibly and safely perform balloon kyphoplasty in the upper thoracic spine.


2010 ◽  
Vol 68 (3) ◽  
pp. 390-395 ◽  
Author(s):  
Bruno Perocco Braga ◽  
Josaphat Vilela de Morais ◽  
Marcelo Duarte Vilela

OBJECTIVE: To evaluate the feasibility, safety and accuracy of pedicle screw placement in the upper thoracic spine using the free-hand technique with the aid of fluoroscopy; to analyze the methods used to verify correct screw positioning intra and postoperatively. METHOD: All patients with instability of the cervicothoracic or upper thoracic spine and at least one screw placed in the segment T1-T6 as part of a posterior construct entered the study. Only C-arm intraoperative fluoroscopy was used to guide screw placement. RESULTS: We obtained excellent positioning in 98.07% of the screws. CT scans precisely demonstrated pedicle wall and anterolateral body violations. There was no hardware failure, no neurological or vascular injury and no loss of alignment during the follow-up period. CONCLUSION: Pedicle screws can be safely placed in the upper thoracic spine when strict technical principles are followed. Only a CT scan can precisely demonstrate vertebral body and medial pedicle cortical violations.


2017 ◽  
Vol 25 (2) ◽  
pp. 230949901772243
Author(s):  
Mun Keong Kwan ◽  
Chee Kidd Chiu ◽  
Chris Yin Wei Chan ◽  
Reza Zamani ◽  
Nils Hansen-Algenstaedt

2019 ◽  
Vol 16 (2) ◽  
pp. 35-41 ◽  
Author(s):  
R. A. Kovalenko ◽  
V. V. Rudenko ◽  
V. A. Kashin ◽  
V. Yu. Cherebillo ◽  
D. A. Ptashnikov

Objective. To analyze the safety and accuracy of pedicle screw placement in the subaxial cervical and upper thoracic spine using patient-specific 3D navigation templates.Material and Methods. The study included 16 patients who underwent transpedicular implantation of screws in the subaxial cervical and upper thoracic vertebrae using patient-specific 3D navigation templates. A total of 88 screws were installed. All patients underwent preoperative CT angiography to assess visualization of the vertebral artery. Customized vertebral models and navigation templates were created using 3D printing technology. Models and templates were sterilized and used during surgery. The results of screw implantation, as well as the safety and accuracy of the placement, were assessed by postoperative CT.Results. The average deviation from the planned trajectory was 1.8 ± 0.9 mm. Deviation was estimated as class 1 (<2 mm) for 57 (64.77 %) screws, class 2 (2–4 mm) for 29 (32.95 %), and class 3 for two (2.27 %). The safety of screw implantation of grade 0 (the screw is completely inside the bone structure) was in 79 (89.77 %) cases, of grade 1 (<50 % of the screw diameter perforates the bone) – in 5 (5.68 %), and of grade 3 – in 2 (2.27 %).Conclusion. Using 3D navigation templates is an affordable and safe method of installing pedicle screws in the cervical and upper thoracic spine. The method can be used as an alternative to intraoperative CT navigation.


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