Outcomes Of Pedicle Screw Fixation Research Articles

Role of 3D printing positioning guide template in pedicle screw fixation of unstable atlas fractures

Objective To investigate the clinical outcomes of pedicle screw fixation assisted with the 3D printing positioning guide template for treatment of unstable atlas fractures. Methods A retrospective case series review was made on 10 patients with unstable atlas fractures undergone direct posterior C1 pedicle screw fixation assisted with the 3D printing drill guide template from September 2012 to May 2015. There were 7 males and 3 females, with a mean age of 52.6 years (range, 23-75 years). All patients complained of neck pain, stiffness and decreased range of motion without neurologic deficit. Preoperative skull traction was used routinely. After the three-dimension reconstruction of cervical vertebrae, ideal trajectory for C1 pedicle screws was designed with a complementary basal template for posterior surface of atlas corresponding anatomical structure. Then the drill guide template was materialized in a rapid prototyping machine and used during operation. Start point and direction of the ideal and actual trajectories were measured after matching the position of the pre- and post-operative patients’ cervical spine. Safety of pedicle screw fixation was assessed in the transverse and sagittal planes of CT scan. Operation time and blood loss were recorded. Visual Analogue Scale (VAS) of neck pain was recorded before operation and 3 months after operation. Clinical efficacy, fracture reduction, stability and surgical complications were reviewed at the follow-up. Results A total of 20 screws were inserted safely. No significant differences existed in deviation of entry point and direction between ideal and actual trajectories (P>0.05). Operation time was 60-90 min (mean, 75 min) and intraoperative blood loss was 110-300 ml (mean, 160 ml). No spinal cord or vertebral artery injury was noted during operation. All patients were followed up for 12-36 months (mean, 20.5 months). VAS was improved from preoperative 7.3(6.3-9.5)points to 1.4(0.3-2.5) points 3 months after operation (P<0.05). All patients had normal range of motion of the cervical spine 3 months after operation. Bony fusion was achieved 6 months after operation. At the follow-up, good cervical alignment was maintained with no instrument failure and C1-2 instability. Conclusion For treatment of unstable atlas fractures, direct posterior C1 pedicle screw fixation assisted with the 3D printing drill guide template can improve the precision of screw placement, reduce complications, and preserve the function of the occipital-atlanto-axial junction. Key words: Atlas; Fracture fixation, internal; Rapid prototyping

Clinical comparative study of two fixation methods for thoracolumbar spine fracture

Objective To compare the clinical results of pedicle screw fixation via the injured vertebra versus across the injured vertebra for thoracolumbar spine fracture. Methods The study reviewed 56 patients (41 males and 15 females,at age range of 21-66 years,mean 41.5 years) with thoracolumbar spine fractures managed with the two fixation methods from June 2005 to December 2008.The fracture segment included T12 in 13 patients,L1 in 27 and L2 in 16.According to the AO classification,there were six patients with type A1.2,29 with type A3.1,nine with type A3.2 and 12 with type A3.3.McCormack load score was 5-8 points (average 6.3 points). The spinal cord injury was classified as grade A in three patients,grade B in four,grade C in eight,grade D in 17 and grade E in 24 according to Frankel scale.The patients were divided into two groups,ie,across vertebral fixation group (27 patients) and via the vertebral fixation group (29 patients).All patients were selectively treated with monosegment bone graft simultaneously.The Cobb' s angle,restoration of the anterior height of the injured vertebra,improvement of spinal canal stenosis rate and Denis scale in local pain and work status were compared between the two groups.The bone graft fusion and spinal cord recovery of both groups were observed during follow-up. Results All patients were followed up for 12-48 months (average 25.8 months).Implantation loosening occurred in one patient 1.5 month after operation in across vertebral fixation group.There were no significant differences in aspects of correction of Cobb' s angle,restoration of the anteriorheight of injured vertebra and improvement of spinal canal stenosis rate postoperatively as well as in aspects of restoration of anterior height of injured vertebra and improvement of spinal canal stenosis rate at the latest follow-up between the two groups ( P ＞ 0.05).The postoperative loss of correction rate of Cobb's angle of both groups existed,with significant difference (P ＜0.05). The differences of the Cobb's angle at the latest follow-up and after operation were significant in the across vertebral fixation group ( P ＜ 0.05) but insignificant in the via vertebral fixation group (P ＞ 0.05 ).Bone graft fusion occurred in 21 patients (78％) in the across vertebral fixation group and in 27 patients (93％) in the via vertebral fixation group ( P ＜ 0.05 ).Denis scale indicated a better recovery in the local pain of via vertebral fixation group compared with the across vertebral fixation group ( P ＜ 0.05 ),but showed no significant differenc e in work status between the two groups ( P ＞ 0.05 ). Conclusions Compared with across vertebral fixation,the pedicle screw fixation via the vertebra has the advantages of higher fusion rate and better correction rate of Cobb' s angle and is a better choice for thoracolumbar spine fracture with posterior approach. Key words: Spinal fractures ; Thoracic vertebrae ; Lumbar vertebrae ; Fracture fixation,internal; Pedicle screws

The Pedicle Screw Fixation With Vertebroplasty Augmentation in the Surgical Treatment of the Severe Osteoporotic Spines

Retrospective clinical study. To present the early clinical results of pedicle screw fixation augmented by vertebroplasty using polymethylmethacrylate in severely osteoporotic patients requiring spine surgery due to the neurologic deficit. It is postulated that combining a formal vertebroplasty-that is, maximum filling of the trabecular space with polymethylmethacrylate-with pedicle screw placement in osteoporotic vertebrae could result in resistance to pullout forces significantly. Between the years 2003 and 2006, pedicle screw placement with vertebroplasty augmentation was performed in 49 patients who had severe osteoporosis and who required spine surgery due to neurologic deficit. Eleven patients with less than 2 years of follow-up and 2 patients who died from unrelated illness were excluded from the study. Thirty-six of 49 patients having minimum 2 years of follow-up were included. Cement augmentation was also performed in segments proximal and distal to instrumentation to prevent junctional segment fractures. Early and late postoperative complications were recorded during follow-up. The mean postoperative follow-up was 37 (24 to 48) months. The average age of the patients was 66 (59 to 78) years. The instrumentation was performed meanly at 5 segments and vertebroplasty was performed averagely at 7 segments. All patients had the T-score value of less than -2.5 from the anteroposterior and lateral lumbar spine and hip views, so regarded as severe osteoporosis. In our study group, there were no extravasation and subsequent thermal neural injury. Four superficial wound infections have been observed and they responded well to local debridement and antibiotics. There were no proximal and distal junctional segment fractures during the follow-up course. Postoperatively, all patients with neurologic symptoms had complete relief of their nerve compression symptoms. In patients requiring spine surgery due to neurologic deficit and having no sufficient time for the medical treatment of severe osteoporosis, pedicle screw fixation with vertebroplasty augmentation and vertebroplasty in segments proximal and distal to the instrumented segments can be good alternative methods to provide well fixation and fusion while preventing proximal and distal junctional fractures. One should be careful about pulmonary cement embolism after such kind of procedures.

Clinical and radiographic outcomes of pedicle screw fixation for upper thoracic spine (T1–5) fractures: a retrospective cohort study of 27 cases

The use of pedicle screws (PSs) for stabilization of unstable thoracolumbar fractures has become the standard of care, but PS efficacy has not been reported in the upper thoracic spine. The primary outcome of this study was to determine the efficacy of PS fixation to achieve and maintain reduction of unstable upper thoracic spine fractures (T1-5). Secondary outcomes included scores on a 1-year postoperative generic health-related quality of life (QOL) questionnaire and postoperative complications. This study was a retrospective analysis and cross-sectional outcome assessment of cases prospectively entered into a spine database from 1997 to 2004. All patients with a traumatic, unstable upper thoracic spine (T1-5) fracture who underwent PS fixation were included. Preoperative CT scans with sagittal plane reformatted images were used to determine kyphotic deformity and compared with immediate postoperative and latest follow-up radiographs or CT scans. Patient charts, operative notes, and the results of postoperative follow-up examinations were reviewed. Patients were mailed the Short Form-36v2 (SF-36 version 2) by an independent study coordinator. Cases involving 27 patients (23 male, 4 female) were evaluated. The patients' mean age was 39.9 years (range 16-73 years). In all, 251 PSs were passed between T-1 and T-8. The mean true kyphotic deformity was 18.2 degrees preoperatively, 8.7 degrees (p < 0.0005) initially postoperatively, and 10.1 degrees at final follow-up (mean 2.3 years postoperatively). The mean SF-36 physical component summary score was 35.89 while the mental component summary score was 56.43 at a minimum of 1-year postoperatively (mean 3.2 years). There were no intraoperative vascular or neural complications. In the hands of fellowship-trained spinal surgeons, PS fixation for reduction and stabilization of upper thoracic spine fractures is a safe and efficacious technique. Health-related QOL outcome data are deficient for spine trauma patients and should be an essential component of quantifying treatment outcomes.