Does the intraoperative 3D-flat panel control of the planned implant position lead to an optimization and increased in safety in the anatomically demanding region C1/2?

BACKGROUND: The aim of this study was to evaluate the applicability and advantages of intraoperative imaging using a 3D flat panel in the treatment of C1/2 instabilities. MATERIALS: Prospective single-centered study including surgeries at the upper cervical spine between 06/2016 and 12/2018. Intraoperatively thin K-wires were placed under 2D fluoroscopic control. Then an intraoperative 3D-scan was carried out. The image quality was assessed based on a numeric analogue scale (NAS) from 0 to 10 (0 = worst quality, 10 = perfect quality) and the time for the 3D-scan was measured. Additionally, the wire positions were evaluated regarding malpositions. RESULTS: A total of 58 patients were included (33f, 25 m, average age 75.2 years, r.:18-95) with pathologies of C2: 45 type II fractures according to Anderson/D'Alonzo with or without arthrosis of C1/2, 2 Unhappy triad of C1/2 (Odontoid fracture Type II, anterior or posterior C1 arch-fracture, Arthrosis C1/2) 4 pathological fractures, 3 pseudarthroses, 3 instabilities of C1/2 because of rheumatoid arthritis, 1 C2 arch fracture). 36 patients were treated from anterior [29 AOTAF (combined anterior odontoid and transarticular C1/2 screw fixation), 6 lag screws, 1 cement augmented lag screw] and 22 patients from posterior (regarding to Goel/Harms). The median image quality was 8.2 (r.: 6-10). In 41 patients (70.7%) the image quality was 8 or higher and in none of the patients below 6. All of those 17 patients the image quality below 8 (NAS 7 = 16; 27.6%, NAS 6 = 1, 1.7%), had dental implants. A total of 148 wires were analyzed. 133 (89.9%) showed a correct positioning. In the other 15 (10.1%) cases a repositioning had to be done (n = 8; 5.4%) or it had to be drawn back (n = 7; 4.7%). A repositioning was possible in all cases. The implementation of an intraoperative 3D-Scan took an average of 267 s (r.: 232-310 s). No technical problems occurred. CONCLUSION: Intraoperative 3D imaging in the upper cervical spine is fast and easy to perform with sufficient image quality in all patients. Potential malposition of the primary screw canal can be detected by initial wire positioning before the Scan. The intraoperative correction was possible in all patients. Trial registration German Trials Register (Registered 10 August 2021, DRKS00026644-Trial registration: German Trials Register (Registered 10 August 2021, DRKS00026644- https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00026644 ).

Effect of subsequent vertebral body fractures on the outcome after posterior stabilization of unstable geriatric fractures of the thoracolumbar spine.

PURPOSE: The purpose of this study was analyzing the effect of subsequent vertebral body fractures on the clinical outcome in geriatric patients with thoracolumbar fractures treated operatively. METHODS: Retrospectively, all patients aged ≥ 60 with a fracture of the thoracolumbar spine included. Further inclusion parameters were acute and unstable fractures that were treated by posterior stabilization with a low to moderate loss of reduction of less than 10°. The minimal follow-up period was 18 months. Demographic data including the trauma mechanism, ASA score, and the treatment strategy were recorded. The following outcome parameters were analyzed: the ODI score, pain level, satisfaction level, SF 36 score as well as the radiologic outcome parameters. RESULTS: Altogether, 73 patients were included (mean age: 72 years; 45 women). The majority of fractures consisted of incomplete or complete burst fractures (OF 3 + 4). The mean follow-up period was 46.6 months. Fourteen patients suffered from subsequent vertebral body fractures (19.2%). No trauma was recordable in 5 out of 6 patients; 42.8% of patients experienced a low-energy trauma (significant association: p < 0.01). There was a significant correlation between subsequent vertebral body fracture and female gender (p = 0.01) as well as the amount of loss of reduction (p = 0.02). Thereby, patients with subsequent vertebral fractures had significant worse clinical outcomes (ODI: 49.8 vs 16.6, p < 0.01; VAS pain: 5.0 vs 2.6, p < 0.01). CONCLUSION: Patient with subsequent vertebral body fractures had significantly inferior clinical midterm outcome. The trauma mechanism correlated significantly with both the rate of subsequent vertebral body fractures and the outcome. Another risk factor is female gender.

Patient-Matched 3-D-Printed Guides for the Insertion of Cervical Pedicle Screws in Tumor Surgery.

BACKGROUND: Pedicle screw fixation in the cervical spine provides biomechanical advantages compared to other stabilization techniques. However, pedicle screw insertion in this area is challenging due to the anatomical conditions with a high risk of breaching the small pedicles and violating the vertebral artery or neural structures. Today, several techniques to facilitate screw insertion and to make the procedure safer are used. 3-D-printed patient-matched guides based on a CT reconstruction are a helpful technique which allows to reduce operation time and to improve the safety of pedicle screw insertion at the cervical spine. CASES: 3-D-printed patient-matched drill guides based on a CT scan with a 3-D reconstruction of the spine were used in two challenging cervical spine surgical tumor cases to facilitate the implantation of the pedicle screws. The screw position was controlled postoperatively by means of the routinely performed CT scan. RESULTS: Postoperative imaging (conventional radiographs and CT scan) revealed the correct position of the pedicle screws. The time needed for screw insertion was short, and the need for intraoperative fluoroscopy could be reduced. There was no intra- or postoperative complication related to the pedicle screw implantation. Both tumors could be removed completely. CONCLUSION: These preliminary results show that 3-D-printed patient-specific guides are a promising tool to support and facilitate the implantation of cervical pedicle screws. The time needed for insertion is short, and intraoperative fluoroscopy time can be reduced. This technique allows for both a meticulous preoperative planning and a correct and therefore safe intraoperative positioning of cervical spine pedicle screws.

Comparison of three different screw trajectories in osteoporotic vertebrae: a biomechanical investigation.

BACKGROUND: Pedicle screw insertion in osteoporotic patients is challenging. Achieving more screw-cortical bone purchase and invasiveness minimization, the cortical bone trajectory and the midline cortical techniques represent alternatives to traditional pedicle screws. This study compares the fatigue behavior and fixation strength of the cement-augmented traditional trajectory (TT), the cortical bone trajectory (CBT), and the midline cortical (MC). METHODS: Ten human cadaveric spine specimens (L1 - L5) were examined. The average age was 86.3 ± 7.2 years. CT scans were provided for preoperative planning. CBT and MC were implanted by using the patient-specific 3D-printed placement guide (MySpine®, Medacta International), TT were implanted freehand. All ten cadaveric specimens were randomized to group A (CBT vs. MC) or group B (MC vs. TT). Each screw was loaded for 10,000 cycles. The failure criterion was doubling of the initial screw displacement resulting from the compressive force (60 N) at the first cycle, the stop criterion was a doubling of the initial screw displacement. After dynamic testing, screws were pulled out axially at 5 mm/min to determine their remaining fixation strength. RESULTS: The mean pull-out forces did not differ significantly. Concerning the fatigue performance, only one out of ten MC of group A failed prematurely due to loosening after 1500 cycles (L3). Five CBT already loosened during the first 500 cycles. The mean displacement was always lower in the MC. In group B, all TT showed no signs of failure or loosening. Three MC failed already after 26 cycles, 1510 cycles or 2144 cycles. The TT showed always a lower mean displacement. In the subsequent pull-out tests, the remaining mean fixation strength of the MC (449.6 ± 298.9 N) was slightly higher compared to the mean pull-out force of the CBT (401.2 ± 261.4 N). However, MC (714.5 ± 488.0 N) were inferior to TT (990.2 ± 451.9 N). CONCLUSION: The current study demonstrated that cement-augmented TT have the best fatigue and pull-out characteristics in osteoporotic lumbar vertebrae, followed by the MC and CBT. MC represent a promising alternative in osteoporotic bone if cement augmentation should be avoided. Using the patient-specific placement guide contributes to the improvement of screws' biomechanical properties.

Midterm outcome after posterior stabilization of unstable Midthoracic spine fractures in the elderly.

BACKGROUND: The evidence for the treatment of midthoracic fractures in elderly patients is weak. The aim of this study was to evaluate midterm results after posterior stabilization of unstable midthoracic fractures in the elderly. METHODS: Retrospectively, all patients aged ≥65 suffering from an acute unstable midthoracic fracture treated with posterior stabilization were included. Trauma mechanism, ASA score, concomitant injuries, ODI score and radiographic loss of reduction were evaluated. Posterior stabilization strategy was divided into short-segmental stabilization and long-segmental stabilization. RESULTS: Fifty-nine patients (76.9 ± 6.3 years; 51% female) were included. The fracture was caused by a low-energy trauma mechanism in 22 patients (35.6%). Twenty-one patients died during the follow-up period (35.6%). Remaining patients (n = 38) were followed up after a mean of 60 months. Patients who died were significantly older (p = 0.01) and had significantly higher ASA scores (p = 0.02). Adjacent thoracic cage fractures had no effect on mortality or outcome scores. A total of 12 sequential vertebral fractures occurred (35.3%). The mean ODI at the latest follow up was 31.3 ± 24.7, the mean regional sagittal loss of reduction was 5.1° (± 4.0). Patients treated with long segmental stabilization had a significantly lower rate of sequential vertebral fractures during follow-up (p = 0.03). CONCLUSION: Unstable fractures of the midthoracic spine are associated with high rates of thoracic cage injuries. The mortality rate was rather high. The majority of the survivors had minimal to moderate disabilities. Thereby, patients treated with long segmental stabilization had a significantly lower rate of sequential vertebral body fractures during follow-up.

[Posttraumatic vertebral disc alterations after B and C type spinal injuries in childhood-Clinical and radiological 10-year results for two cases]. / Posttraumatische Bandscheibenalterationen nach B- und C-Verletzungen der Wirbelsäule im Kindesalter ­ Klinische und radiologische Zehnjahresergebnisse für zwei Fälle.

Pediatric traumatic vertebral injuries usually present as stable A (AOspine classification) fractures, whereas B and C injuries are relatively uncommon. In contrast to adults the appropriate treatment strategy in children remains an issue of debate.The data from two pediatric patients admitted with B and C type spinal injuries in 2007 and 2008 were retrospectively analyzed. The initial diagnostics were performed via computed tomography (CT) and an additional magnetic resonance imaging (MRI) was carried out in one case.The clinical and radiological follow-up controls were carried out after 77 and 66 months as well as 123 and 112 months, respectively. In both cases thoracolumbar MRI scans revealed degenerative alterations of the ventral half of the L1/L2 disc with a regular disc signal in the dorsal segment at the first follow-up and a progressive disc degeneration in one patient at the second follow-up.Surgical treatment of pediatric B and C type injuries via open reduction and temporary monosegmental posterior screw and rod instrumentation results in satisfactory clinical and radiological outcomes. In the absence of vertebral burst fractures, the function and stability of discoligamentous injuries in children can be restored without any additional osseous fusion.

Osteoporotic vertebral body fractures of the thoracolumbar spine: indications and techniques of a 360°-stabilization.

Unstable vertebral body fragility fractures of the thoracolumbar spine can occur with or without relevant trauma. Initially, a standardized diagnostic algorithm including magnetic resonance tomography is recommended to detect accompanied further vertebral body fractures, to interpret the individual fracture stability, and to screen for relevant traumatic intervertebral disc lesions. Aim of the therapy is to assure fast mobilization and to maintain spinal alignment. Unstable fracture morphology is defined by vertebral body fractures including a relevant defect of the posterior vertebral cortex as well as type B or C fractures. With respect of type A fractures, a combined anterior-posterior approach including a primary cement-augmented posterior stabilization and anterior spondylodesis is indicated in those patients with relevant intervertebral lesions or in those suffering from high-energy accidents resulting in unstable burst-type fractures. The others will benefit from hybrid stabilizations including cement-augmented posterior stabilizations and cement augmentation (kyphoplasty) of the fractured level to gain a ventral transosseous stability. In addition, individually adapted antiosteoporotic therapy is essential.

[Injuries of the thoracolumbar spine in children]. / Verletzungen der kindlichen thorakolumbalen Wirbelsäule.

BACKGROUND: Injuries of the thoracolumbar spine in children are rare and challenging for the treating physician. Besides knowledge of fracture treatment, the anatomical particularities of the spine in children are of great importance. METHODS: The article gives an overview of the diagnosis and therapy with the most common classification of injuries of the thoracolumbar spine. RESULTS: Taking into account the children's age and the fracture morphology most cases can be treated conservatively, especially because the young spine has great potential for remodelling. The older the child becomes, the more smoothly the transition to adult treatment occurs; thus, unstable fractures should be treated with surgery. CONCLUSION: The difficult indication and the specific characteristics of surgery necessitate treatment in a spine centre with experience with surgery on children.

[Delayed indications for additive ventral treatment of thoracolumbar burst fractures : What correction loss is to be expected]. / Zeitverzögerte Indikationsstellung zur additiv ventralen Versorgung thorakolumbaler Berstungsfrakturen : Welcher Korrekturverlust ist zu erwarten.

INTRODUCTION: There is a general consensus that unstable vertebral body fractures of the thoracolumbar junction with a B type fracture or a high load shear index need to be surgically stabilized, primarily by a dorsal approach. The authors believe that there are indications for an additional ventral spondylodesis in cases of reduction loss or a relevant intervertebral disc lesion in magnetic resonance imaging (MRI) 6 weeks after dorsal stabilization. However, in cases of unstable vertebral fractures it remains unclear if a delayed anterior spondylodesis will lead to unacceptable loss of initial reduction. MATERIAL AND METHODS: A total of 59 patients were included in this study during 2013 and 2014. All patients suffered from a traumatic vertebral fracture of the thoracolumbar junction and were initially treated with a dorsal short segment stabilization. All vertebral body fractures had a load shear index of at least 5 or were B type fractures. An x-ray control was carried out after 2 and 6 weeks and MRI was additionally performed after 6 weeks. An additional ventral spondylodesis was recommended in patients showing a reduction loss of at least 5° and in patients with relevant intervertebral disc lesions. The extent of the reduction loss was analyzed. Other parameters of interest were the fracture level, fracture classification, patient age and surgical technique (e.g. implant, index screw, laminectomy and cement augmentation). RESULTS: The patient collective consisted of 23 women and 36 men (average age 51 years ± 17 years). The mean reduction loss was 5.1° (± 5.2°) after a mean follow-up of 60 days (± 56 days). The reduction loss was significantly higher when polyaxial implants were used compared to monoaxial dorsal fixators (10.8° versus 4.0°, p < 0.001). There was a significantly higher reduction loss in those patients who received a laminectomy (11.3° versus 4.3°, p = 0.01) but there were no significant differences if an index screw was used (4.5° versus 5.3°). Additionally, there was a significantly lower reduction in the subgroup of patients 60 years or older who were stabilized using cement-augmented screws (3.9° versus 11.3°, p = 0.02). The mean reduction loss was 2.8° (± 2.5°) in patients treated with a monoaxial implant, cement-augmented if 60 years or older and without laminectomy (n = 39). There was no significant correlation between reduction loss and the other parameters of interest, such as fracture morphology with classification according to the working group on questions of osteosynthesis (AO) and McCormack or fracture level. CONCLUSION: Delayed indications for an additional ventral spondylodesis in patients with unstable thoracolumbar vertebral fractures and initial dorsal stabilization will cause no relevant reduction loss if monoaxial implants are used and laminectomy can be avoided. Additionally, cement augmentation of the pedicle screws seems to be beneficial in patients 60 years of age or older.

[Release of moveable segments after dorsal stabilization : Impact on affected discs]. / Freigabe von Bewegungssegmenten nach dorsaler Stabilisierung : Auswirkung auf die betroffenen Bandscheiben.

BACKGROUND: Bisegmental dorsal stabilization is a common treatment option for instable compression fractures of the thoracolumbar spine; however, it remains unknown to what extent bridging compromises intervertebral discs. OBJECTIVES: The purpose of this study was to determine the disc height and functional features in comparison to healthy intervertebral discs after removal of the dorsal fixator and particularly under consideration of the time span between dorsal stabilization and implant removal (IR). MATERIAL AND METHODS: The IR was performed in 19 patients after an average of 13 months (range 8-24 months) after dorsal stabilization of instable vertebral compression fractures of the thoracolumbar junction and lumbar spine. An additional ventral monosegmental spondylodesis was performed in 10 patients with incomplete burst fractures. Thus, a total of 28 intervertebral discs were temporarily bridged (bridged discs), with an adjacent endplate fracture in 10 (injured discs) and no adjacent bony lesion in 18 discs (healthy discs). The intervertebral discs superior and inferior to the instrumentation were selected as controls (control discs). Standardized conventional lateral radiographs were taken prior to and after IR as well as after 6 months. Additionally, standardized lateral radiographs in flexion and extension were taken. The intervertebral disc height (disc height) was determined by two independent board approved orthopedic observers by measuring the anterior, central and dorsal intervertebral disc spaces on all lateral radiographs as well as the intervertebral disc angles (disc angle) defined by the intervertebral upper and lower endplates in the flexion and extension views. Intradisc function (disc function) was defined as the difference between the disc angle in extension and flexion. The measurements were repeated after 12 months. Univariate analysis was performed using ANOVA and significance was set at p < 0.05. Interobserver and intraobserver comparisons of the disc heights and the disc angles were determined with intraclass correlation coefficients. RESULTS: No significant differences were seen in disc function and disc height between the controls and the bridged discs at all times of measurement; however, injured discs showed a significantly reduced disc height and disc angle in extension compared to healthy discs (p = 0.028 and p = 0.027, respectively). Additionally, patients with IR during the first 12 months had significantly reduced disc heights compared to those patients with delayed IR within the second postoperative year (p = 0.018). Interobserver and intraobserver agreement for disc function was 0.80 (95 % confidence interval CI: 0.68-0.88) and 0.85 (95 % CI 0.76-0.90), respectively. The interobserver and intraobserver correlations for disc height were 0.85 (95 % CI: 0.76-0.90) and 0.93 (95 % CI 0.88-0.95), respectively. CONCLUSION: Bridging of an intervertebral disc with IR within 24 months does not cause immediate loss of disc function or reduction of disc height; however, temporary bridging in combination with an adjacent endplate fracture causes significant reduction of disc height and loss of extension. Additionally, no beneficial effects could be seen by reducing the time span between stabilization and IR to below 12 months.

[Multiplanar reconstruction with mobile 3D image intensifier. Surgical treatment of proximal humerus fractures]. / Multiplanare Rekonstruktion mit mobilem 3D-Bildwandler. Operative Versorgung proximaler Humerusfrakturen.

PURPOSE: The aim of this study was to analyze the applicability and advantages of the intraoperative use of a mobile 3D C-arm with multiplanar imaging for surgery of acute proximal humerus fractures. MATERIALS AND METHODS: In this study 20 patients (11 female, 9 male, median age 70 years, range 35-91 years) with dislocated proximal humerus fractures (6 with 2 segments, 10 with 3 segments and 4 with 4 segments) were included. Preoperatively 3D scanning was performed and a reevaluation of the fracture in comparison to the plain radiographs was performed. After operative treatment another scan was performed to evaluate technical complications. RESULTS: In comparison to the multiplanar reconstructions fracture morphology could not be correctly detected in 5 out of the 20 cases with plain radiographs. The preoperative image quality of the multiplanar reconstructions showed a significantly better assessment in comparison to the image quality with osteosynthesis (p < 0.05). The screws had to be replaced in 5 of the 20 patients. CONCLUSION: Intraoperative 3D imaging with mobile image intensifier enables an accurate analysis of fracture morphology. Furthermore a quasi real time preoperative planning, evaluation of reduction and implant position with immediate operative relevance can be realized.

[How many generalists and how many specialists does orthopedics and traumatology need?]. / Wie viel Generalist und wie viel Spezialist braucht die Orthopädie und Unfallchirurgie?

The training in orthopedic and trauma surgery has changed significantly with the introduction of the new residency program. The contents taught have already been reduced in breadth and the current developments in the outpatient and particularly in the clinical landscape also contribute to increasing specialization. This trend favors structures in which comprehensive medical care for the population in Germany in orthopedic and trauma surgery appears to be endangered and in which the future efforts for e.g. polytraumatised patients need to be questioned. The Young Forum of the German Society for Orthopedics and Traumatology actively accompanies a discussion about the necessity and value of generalists to ensure the level of care in Germany in addition to the specialists.

3D-based navigation in posterior stabilisations of the cervical and thoracic spine: problems and benefits. Results of 451 screws.

INTRODUCTION: Navigated procedures in spinal surgery have been established due to an increasing demand for precision. Especially, 3D C-arms connected to navigation systems are being used more often and can be utilised intraoperatively for the planning and controlling of screw positions. This prospective study analyses our experiences with 3D-based navigation in posterior stabilisations in the cervical and thoracic spine. METHODS: A 3D C-Arm (Ziehm Vision Vario 3D(®)) was connected to a navigation system (VectorVision, Brainlab(®)) and used for the placement of, in total, 451 screws among 67 patients. Of those, 14 patients had to undergo operations in the cervical and 53 in the thoracic spine. Postoperatively, the positioning was observed with computed tomography (CT). RESULTS: The application time is approximately 6 min. In total, 354/451 (78.5%) screws could be inserted assisted with navigation, and 272/451 (60.3%) were controlled intraoperatively. Regarding the cervical spine, in 87.1% (61/70) of the screws, the navigation procedure was uneventful. The positioning of 63.2% (43/68) of the screws was checked intraoperatively. In the upper thoracic spine, 77% (293/381) could be placed with navigation and 59.6% (227/381) were controlled intraoperatively. Occasionally, the scanning setup was problematic. Correct placement was seen in 92.7% of screws; for the remaining screws, no revision was needed. CONCLUSIONS: Intraoperative 3D imaging navigation for posterior spinal stabilisations is technically feasible and reliable in clinical use. The image quality depends on the individual bone density. With undisturbed visibility of the vertebral body, the reliability of 3D-based navigation is comparable to that of CT-based procedures. Additionally, it has the advantage of skipping the preoperative acquisition of data as well as the matching process, with reduced radiation doses.

Anterior column reconstruction in thoracolumbar injuries utilizing a computer-assisted navigation system.

BACKGROUND: Discectomy, corpectomy, and resection of isolated posterior wall fragments are technically demanding steps requiring maximum surgical precision during anterior reconstruction of the unstable thoracolumbar spine. PURPOSE: This study investigates the feasibility of computer-aided guidance for these steps. It also analyzes the precision, advantages, and disadvantages of the procedure. STUDY DESIGN: Controlled clinical trial. PATIENT SAMPLE: 21 patients were included in the trial group; the control group consisted of 10 patients. OUTCOME MEASURES: Total time for surgery was noted. To assess surgical precision, decentralization of the cage was measured in postoperative X-rays. Additionally, parallel alignment of vertebral body endplates with the cage was evaluated in postoperative CT scans. METHODS: Vertebral body fractures of the thoracolumbar spine addressed by disc-/corpectomy and subsequent cage interposition for anterior reconstruction were included. All surgical steps were performed under endoscopic assistance. In the trial group, disc- and corpectomy were performed under computer-aided guidance; in the control group, no computer navigation was utilized. In cases of initial neurological deficit after trauma, the patients underwent emergency laminectomy during the initial posterior stabilization procedure. During the second-stage anterior procedure, resection of the posterior wall fragment with the aid of computer-aided navigation was performed. RESULTS: Fractures were localized between Th9 and L1 in the trial group, and Th10 and L1 in the control group. Time for surgery was significantly shorter in the control group: 1.7 h ± 0.5, as opposed to 3.8 h ± 1.0 in the trial group (p < 0.0005). In contrast, data on surgical precision did not show statistically significant differences between both groups for either decentralization or parallel endplate alignment of cages. Remarkably, we noted two cases of subsidence in bilevel cages in the control group, whereas this was only noted in one case in the trial group. However, this difference was not statistically significant. There were five patients with initial neurological deficits. At the time of follow-up, the neurological statuses of all five had improved by at least one Frankel grade. CONCLUSIONS: Computer-aided guidance in anterior reconstruction of the thoracolumbar spine is a technically feasible option that may aid in the performance of disc- and corpectomy, as well as the resection of isolated posterior wall fragments in cases with initial neurological compromise. However, total time for surgery is significantly prolongated by this technique. There were no differences in the precision of cage positioning between groups. However, during discectomy, the use of computer navigation may aid in the protection of adjacent endplates, as there was a trend towards fewer cases with cage subsidence in the navigated group.