Epidemiology of Surgically Treated Spinal Tumors: A Multicenter Surveillance Study of 9686 Patients from the German Spine Registry (DWG Register).

Tumors of the spine are challenging in terms of diagnoses and interdisciplinary treatment. This study was conducted to evaluate and characterize a large multicenter cohort of surgically treated spine tumor patients.Data of the German Spine Society (DWG) were used to characterize a cohort of all surgically treated spine tumor cases that were registered between 2017 and 2021. Subgroup analysis was performed for tumor entity, tumor localization, height of most severely affected segments, surgical treatment, and demographic parameters.In total, there were 9686 cases, of which 6747 were "malignant", 1942 were "primary benign", 180 were "tumor-like lesions", and 488 were "other" spinal tumors. Subgroups showed differences in number of affected segments as well as localization. There were further significant differences in surgical complication rates (p = 0.003), age (p < 0.001), morbidity (p < 0.001), and duration of surgery (p = 0.004).This is a representative study on spinal tumors from a large spine registry and allows for the epidemiological characterization of surgically treated tumor subgroups and quality control of registry data.

Biomechanical In Vitro and Finite Element Study on Different Sagittal Alignment Postures of the Lumbar Spine During Multiaxial Daily Motion.

Lumbar lordotic correction (LLC), the gold standard treatment for sagittal spinal malalignment (SMA), and its effect on sagittal balance have been critically discussed in recent studies. This paper assesses the biomechanical response of the spinal components to LLC as an additional factor for the evaluation of LLC. Human lumbar spines (L2L5) were loaded with combined bending moments in flexion (Flex)/extension (Ex) or lateral bending (LatBend) and axial rotation (AxRot) in a physiological environment. We examined the dependency of AxRot range of motion (RoM) on the applied bending moment. The results were used to validate a finite element (FE) model of the lumbar spine. With this model, the biomechanical response of the intervertebral discs (IVD) and facet joints under daily motion was studied for different sagittal alignment postures, simulated by a motion in Flex/Ex direction. Applied bending moments decreased AxRot RoM significantly (all P < 0.001). A stronger decline of AxRot RoM for Ex than for Flex direction was observed (all P < 0.0001). Our simulated results largely agreed with the experimental data (all R2 > 0.79). During the daily motion, the IVD was loaded higher with increasing lumbar lordosis (LL) for all evaluated values at L2L3 and L3L4 and posterior annulus stress (AS) at L4L5 (all P < 0.0476). The results of this study indicate that LLC with large extensions of LL may not always be advantageous regarding the biomechanical loading of the IVD. This finding may be used to improve the planning process of LLC treatments.

The diagnostic value of cytokines for the discrimination of vertebral osteomyelitis and degenerative diseases of the spine.

Vertebral osteomyelitis (VO) is a primary infection of the endplates of the vertebral bodies with secondary infection of the adjacent intervertebral discs. Diagnosis is often delayed due to unspecific symptoms and a lack of specific infection markers. In this prospective study, we determined the suitability of 27 cytokines for the discrimination of VO and degenerative diseases of the spine and compared its diagnostic potential in relation to the C-reactive protein (CRP), which is widely used as a non-specific inflammation marker in clinical diagnostics. The patients included in this study underwent surgical stabilization of the lumbar and/or thoracic spine with removal of 1 or more affected intervertebral discs, as therapy for VO (n = 16) or for erosive osteochondrosis (EO, control group, n = 20). We evaluated the cytokine and CRP concentrations before (pre-OP = -20-0d where 0 means the day of surgery) and after surgery (post-OP) on days 3-5, 6-11, 40-56, and 63-142. Compared to the control patients pre-OP, a significantly higher elevation of the 4 cytokines IL-6, IL-8, IL-12 (p70), and VEGF as well as CRP were found in the VO patients, showing an area under the curve > 0.80 pre-OP. No significant differences were observed between VO patients with high and low virulent bacteria with respect to all 5 elevated biomarkers. This is the first prospective study in which a broad spectrum of 27 cytokines was analysed via multiplex assay using sera from patients with and without VO. Our results show that, in addition to CRP, 4 different cytokines were significantly altered in VO but not control patients. The results implicate that these candidate cytokines may be used in a multiplex assay for discrimination between VO and degenerative diseases of the spine.

Quality of life and mortality after surgical treatment for vertebral osteomyelitis (VO): a prospective study.

PURPOSE: Vertebral osteomyelitis (VO) has a high mortality and leads to chronic pain and functional disability. Surgical treatment is often necessary. To date, little is known about the consequences of surgery on patient outcome. The aim of this study was to determine the quality of life (QoL) and mortality rates of surgically treated VO patients for a period of 2 years. METHODS: Patients with VO undergoing surgical treatment in a tertiary referral hospital from 2008 to 2015 were included prospectively. Data were collected before (T0) as well as 1 year (T1) and 2 years (T2) post-surgery. Within the European Spine Tango registry, prospective patient and QoL data were collected using validated outcome scores: Oswestry Disability Index, Short Form 36/EuroQol, Visual Analog Scale, and Core Outcome Measures Index. RESULTS: From 195 patients surgically treated for VO, QoL data were available from 136 patients at T0, 100 patients at T1, and 82 patients at T2, respectively. The 1- and 2-year mortality rates were 20% and 23%. Mainly all QoL outcome scores showed significant improvement at T1 and did not change significantly from T1 to T2. CONCLUSION: Surgical treatment of VO patients leads to significantly improved QoL. Nevertheless, QoL levels were below those of the general population. Our results underscore that spine disability questionnaires measuring QoL are mandatory to demonstrate comprehensively the severity of this entity. Our study confirms a high mortality and points out the role of VO as a potentially life-threatening condition.

Vertebral Osteomyelitis After Spine Surgery: A Disease With Distinct Characteristics.

STUDY DESIGN: Prospective cohort study. OBJECTIVE: We aimed to determine the 2-year survival and to identify clinical and microbiological characteristics of patients with native vertebral osteomyelitis (VO) as compared to postoperative VO to find further strategies for improvement of the management of VO. SUMMARY OF BACKGROUND DATA: A relevant subgroup (20%-30%) of patients with VO has a history of spine surgery. Infection in these patients might be clinically different from native VO. However, clinical, microbiological, and outcome characteristics of this disease entity have not been well studied as most trials either excluded these patients or are limited by a small cohort and short observation period. METHODS: Between 2008 and 2013, patients who presented at a tertiary care center with symptoms and imaging findings suggestive of VO were reviewed by specialists in infectious diseases, clinical microbiology, and orthopedics to confirm the diagnosis and followed prospectively for a period of 2 years. Statistical analysis for group comparisons, survival analysis, and uni- and multivariable Cox regression models were performed. RESULTS: Thirty percent of the patients with VO (56/189) reported a history of spine surgery in the same segment. Patients with postoperative infection had a lower ASA score (American Society of Anesthesiologists) (P = 0.01) and were less likely to suffer from comorbidities compared to native cases (P = 0.003). Infections caused by coagulase-negative staphylococci (33.3 vs. 6.5%, P < 0.001) and other bacteria of the skin flora (15.2 vs. 0%, P = 0.002) were more prevalent in postoperative patients. Suffering from native VO increased the 2-year mortality risk 3-fold, also when adjusted for the remaining risk factors ASA score and number of comorbidities (hazard ratio 2.916 [95% confidence interval 1.215 -6.999], P = 0.017). CONCLUSION: Beside clear microbiological differences, the significant better 2-year survival supports the concept of postoperative VO presenting a distinct disease entity. The subtle disease presentation of patients with postoperative VO should not attenuate clinical suspicion of physicians. LEVEL OF EVIDENCE: 3.

Biomechanical In Vitro Test of a Novel Dynamic Spinal Stabilization System Incorporating Polycarbonate Urethane Material Under Physiological Conditions.

Posterior dynamic stabilization systems (PDSS) were developed to provide stabilization to pathologic or hypermobile spinal segments while maintaining the healthy biomechanics of the spine. Numerous novel dynamic devices incorporate the temperature and moisture dependent material polycarbonate urethane (PCU) due to its mechanical properties and biocompatibility. In this study, standardized pure moment in vitro tests were carried out on human lumbar spines to evaluate the performance of a device containing PCU. An environmental chamber with controlled moisture and temperature was included in the setup to meet the requirements of testing under physiological conditions. Three test conditions were compared: (1) native spine, (2) dynamic instrumentation, and (3) dynamic instrumentation with decompression. The ranges of motion, centers of rotation, and relative pedicle screw motions were evaluated. The device displayed significant stiffening in flexion-extension, lateral bending, and axial rotation load directions. A reduction of the native range of motion diminished the stiffening effect along the spinal column and has the potential to reduce the risk of the onset of degeneration of an adjacent segment. In combination with decompression, the implant decreased the native range of motion for flexion-extension and skew bending, but not for lateral bending and axial rotation. Curve fittings using the sigmoid function were performed to parameterize all load-deflection curves in order to enhance accurate numerical model calibrations and comparisons. The device caused a shift of the center of rotation (COR) in the posterior and caudal direction during flexion-extension loading.

[Reduction of needlestick injuries by 48 % in 1 year : Effects of improvement of the safety concept according to the European Union Council directive 2010/32/EU at a large regional hospital]. / Reduktion von Nadelstichverletzungen um 48 % in einem Jahr : Auswirkungen einer Verbesserung des Sicherheitskonzeptes nach der EU-Direktive 2010/32/EU an einem großen regionalen Krankenhaus.

BACKGROUND: Needlestick injuries (NSI) are potentially infectious injuries from sharp or pointed medical instruments and through contact with blood on mucous membranes or nonintact skin. Although the European Union (EU) Council directive 2010/32/EU on the prevention of NSI was implemented in EU countries in 2013, information on the effectiveness of the measures is limited. OBJECTIVE: The aim of this study was to evaluate the effectiveness of a safety concept according to the EU Council Directive 2010/32/EU on prevention of NSI. MATERIAL AND METHODS: In 2016 the NSI safety concept at a large regional hospital was improved according to 2010/32/EU, specifically by an update of blood screening profiles and standard operating procedures (SOP), better dissemination of information to employees and complete conversion to safety cannulas and scalpels. The medical records of all NSIs from 2015-2017 were retrospectively anonymized and evaluated and a cost analysis was performed. RESULTS: The number of NSIs in 2017 was significantly reduced by 48.4% as compared to 2016 and NSIs with scalpels were completely prevented. The proportion of employees with NSIs who were adequately immunized against hepatitis B was significantly increased to 84.1% in 2017. Furthermore, identification of the index patient was significantly increased to 82.5% in 2017. The cost of avoiding NSIs increased by a total of 24.1% in 2017 as compared to 2015 before introduction of the safety concept. CONCLUSION: Implementation of the EU Council directive 2010/32/EU, resulted in an almost 50% reduction in NSIs over 1 year, including the complete prevention of NSIs due to scalpels. In addition, the anamnestic presence of immunization against hepatitis B and index patient identification were significantly increased.

The sacral screw placement depending on morphological and anatomical peculiarities.

PURPOSE: Various pathologies of the lumbosacral junction require fusion of the L5/S1 segment. However, pseudarthroses, which often come along with sacral screw loosening, are problematic. The aim of the present investigation was to elaborate the morphological features of the L5/S1 segment to define a so-called "safe zone" for bi- or tricortical screw placement without risking a damage of the iliac vessels. METHODS: A total of one hundred computed tomographies of the pelvis were included in this investigation. On axial and sagittal slices, pedicle morphologies, the prevertebral position of the iliac vessels, the spinal canal and the area with the largest bone density were analyzed. RESULTS: Beginning from the entry point of S1-srews iliac vessels were located at an average angle of 7° convergence, the spinal canal at 38°. Bone density was significantly higher centrally with a mean value of 276 Hounsfield Units compared to the area of the Ala ossis sacri. The largest intraosseous screw length could be achieved at an angle of 25°. The average pedicle width was 20 mm and the pedicle height 13 mm. CONCLUSIONS: A "safe-zone" for bicortical screw placement at S1 with regard to the course of the iliac vessels could be defined between 7° and 38° convergence. Regarding the area offering the largest bone density and the maximal possible screw length, a convergence of 25° is recommended at S1 to reduce the incidence of screw loosening. Screw diameter, as a further influence factor on screw holding, is limited by pedicle height not pedicle width.

The diagnostic value of soluble urokinase-type plasminogen activator receptor (suPAR) for the discrimination of vertebral osteomyelitis and degenerative diseases of the spine.

BACKGROUND: There is still a challenge in discriminating between vertebral osteomyelitis and degenerative diseases of the spine. To this end, we determined the suitability of soluble urokinase-type plasminogen activator receptor (suPAR) and compared the diagnostic potential of suPAR to CRP. METHODS: Patients underwent surgical stabilization of the lumbar and/or thoracic spine with removal of one or more affected intervertebral discs, as therapy for vertebral osteomyelitis (n = 16) or for erosive osteochondrosis (control group, n = 20). In this prospective study, we evaluated the suPAR and CRP levels before (pre-OP) and after surgery (post-OP) on days 3-5, 6-11, 40-56, and 63-142. RESULTS: The suPAR levels in vertebral osteomyelitis patients were significantly higher than those from controls pre-OP, 3-5 days post-OP, and 6-11 days post-OP. Significantly higher CRP levels were observed in the vertebral osteomyelitis group than in the controls pre-OP and 6-11 days post-OP. Levels of suPAR and CRP correlated positively in all patients in the pre-OP period: r = 0.63 (95% CI: 0.37-0.79), p < 0.0001. The values for the area under the receiver operating characteristics curve (AUC) for pre-OP and the overall model post-OP were 0.88 (95% CI: 0.76-1.00) and 0.84 (95% CI: 0.71-0.97) for suPAR, 0.93 (95% CI: 0.85-1.00) and 0.77 (95% CI: 0.62-0.93) for CRP, and 0.98 (95% CI: 0.96-1.00) and 0.91 (95% CI: 0.82-1.00) for the combination of suPAR and CRP. The AUC for suPAR pre-OP revealed an optimum cut-off value, sensitivity, specificity, NPV, and PPV of 2.96 ng/mL, 0.69, 1.00, 0.80, and 1.00, respectively. For CRP, these values were 11.58 mg/L, 0.88, 0.90, 0.90, and 0.88, respectively. CONCLUSION: The present results show that CRP is more sensitive than suPAR whereas suPAR is more specific than CRP. Moreso, our study demonstrated that improvement in the diagnostic power for discrimination of vertebral osteomyelitis and degenerative diseases of the spine can be achieved by a combination of both suPAR and CRP. TRIAL REGISTRATION: ClinicalTrials.gov, NCT02554227, posted Sept. 18, 2015, and updated Aug. 13, 2019.

Influence of additional cement augmentation on endplate stability in circumferential stabilisation of osteoporotic spine fractures.

BACKGROUND: Anterior stabilisation of osteoporotic spine fractures is uncommon but necessary in the case of complex vertebral body comminution. The purpose of this study was to investigate the effect of additional cement-augmentation on the endplate stability. METHODS: Twelve human cadaveric lumbar spines were divided in two groups: (A) posterior cement-augmented pedicle screw/rod-based instrumentation of L3 to L5, posterior decompression of L4/5 and partial corpectomy of L4 and (B) same experimental setup with additional cement-augmentation of the adjacent endplates. A cyclic loading test was performed at a frequency of 3 Hz, starting with a peak of 500 N for the first 2.000 cycles, up to 950 N for 100.000 cycles under a general preload with 50 N. All specimens were evaluated with regard to a potential collapse of the adjacent endplates. Subsequently, the maximum zero-time failure load of all specimens was determined using a universal testing machine. FINDINGS: The median T-score of bone density was -4.32 (range -2.97 to -5.59), distributed equally in the two groups (average age 83 years). The specimen of the endplate-augmented group showed a significant higher failure load compared to non-endplate-augmented cadavers (group A: 2038 N, group B: 2990 N, p = 0.03). All specimens passed the full cyclic loading protocol with 100.000 cycles. No significant difference was observable regarding the adjacent endplate subsidence. INTERPRETATION: Additional cement augmentation in circumferential stabilisation resulted in a significant enhancement of the endplate stability regarding the maximum axial load, while the cyclic loading did not significantly enhance the fatigue endurance of the vertebral endplates over the 100,000 cycles tested.

Material failure in dynamic spine implants: are the standardized implant tests before market launch sufficient?

PURPOSE: International Standards Organization (ISO) 12189 and American Society for Testing and Materials F2624 are two standard material specification and test methods for spinal implant devices. The aim of this study was to assess whether the existing and required tests before market launch are sufficient. METHODS: In three prospective studies, patients were treated due to degenerative disease of the lumbar spine or spondylolisthesis with lumbar interbody fusion and dynamic stabilization of the cranial adjacent level. The CD HORIZON BalanC rod and S4 Dynamic rod were implanted in 45 and 11 patients, respectively. RESULTS: A fatigue fracture of the material of the topping off system has been found in five cases (11%) for the group fitted with the CD HORIZON BalanC rod. In the group using the S4 Dynamic rod group, a material failure of the dynamic part was demonstrated in seven patients (64%). All three studies were interrupted due to these results, and a report to the Federal Institute for Drugs and Medical Devices was generated. CONCLUSION: Spinal implants have to be checked by a notified body before market launch. The notified body verifies whether the implants fulfil the requirements of the current standards. These declared studies suggest that the current standards for the testing of load bearing capacity and stand ability of dynamic spine implants might be insufficient. Revised standards depicting sufficient deformation and load pattern have to be developed and counted as a requirement for the market launch of an implant. These slides can be retrieved under Electronic Supplementary Material.

Injuries in equestrian vaulting: results of a prospective study.

BACKGROUND: Equestrian vaulting is a sport, particularly popular among children and adolescents, in which gymnastic and dance routines are performed on horseback. Current data regarding injuries and thus, the risks of this sport, is meager and based only on retrospective studies. METHODS: In the current prospective study, 233 active members of a vaulting club were questioned monthly from November 2014 until October 2015. In addition to general information (training, competitions), the questionnaire collected the number of competitions, the competitive class, the discipline (single, team, Pas-de-Deux), and injuries (type, localization, treatment). RESULTS: There were 102 documented events resulting in 125 injuries, yielding an average 31.64 days of training lost. Each vaulter suffered an average 0.44 injuries per year. Frequency of injury was 2.15 injuries per 1000 training hours. Injuries occurred most often to the lower and upper extremities. Most common were bruises and muscle injuries. Injury risk increased with increasing age, number of falls from the horse, increasing competitive level, number of tournament entries and events (P=0.006), and previous injuries (P=0.010). CONCLUSIONS: Our study found that vaulting has a low risk of injury comparable to non-contact sports. The best focus for injury prevention strategies is on older vaulters at higher competitive levels performing more complex routines.

To fuse or not to fuse: a survey among members of the German Spine Society (DWG) regarding lumbar degenerative spondylolisthesis and spinal stenosis.

INTRODUCTION: Surgical treatment methods for degenerative spondylolisthesis (decompression versus decompression and fusion) have been critically debated. The medical care situation is almost unknown for either treatment. Therefore, the aim of the present study was to provide information regarding the use of parameters for decision-making and the employment of surgical techniques. MATERIALS AND METHODS: A web-based survey was performed among members of the German-Spine-Society (DWG). Information regarding participant characteristics (specialty, age, DWG certification status, number of spine surgeries performed at the participant's institution each year, institutional status), estimates of the use of both treatment options, clinical and morphological decision-making criteria for additive fusion, and the surgical technique used was queried. RESULTS: 305 members (45% neurosurgeons/ 55% orthopedic or trauma surgeons) participated in the present study. The participants estimated that in 41.7% of the cases, decompression only was required, while 55.6% would benefit from additional fusion. Among the participants, 74% reported that low back pain was an important indicator of the need for fusion if the numerical rating scale for back pain was at least 6/10. The most commonly used decompression technique was minimally invasive unilateral laminotomy, whereas open approach-based interbody fusion with transpedicular fixation and laminotomy was the most frequently used fusion technique. Specialty, age, certification status, and institutional status had a partial effect on the responses regarding indications, treatment and surgical technique. CONCLUSIONS: The present survey depicts the diversity of approaches to surgery for degenerative spondylolistheses in Germany. Considerable differences in treatment selection were observed in relation to the participants' educational level and specialty.

Biomechanical testing of a polycarbonate-urethane-based dynamic instrumentation system under physiological conditions.

BACKGROUND: Posterior dynamic stabilization systems are developed to maintain the healthy biomechanics of the spine while providing stabilization. Numerous dynamic systems incorporate polycarbonate urethane with temperature- and moisture-dependent material properties. In the underlying study, a novel test rig is used to evaluate the biomechanical performance of a system containing polycarbonate urethane. METHODS: The test rig is composed of two hydraulic actuators. An environmental chamber, filled with water vapor at body temperature, is included in the set up. The translational and rotational degrees of freedom of vertebrae and pedicle screws are measured using a magnetic tracking system. The Transition® device is tested in five lumbar spines (L2-L5) of human cadavers. Pure moment tests are performed for flexion-extension, lateral bending, and axial rotation. Three test conditions are compared: 1. native specimens, 2. dynamic instrumentation at L4-L5, 3. dynamic instrumentation with decompression at L4-L5. FINDINGS: The ranges of motion, the centers of rotation, and the pedicle screw loosening are calculated and evaluated. During daily motions such as walking, the loads on the lumbar spine differ from the standardized test protocols. To allow a reproducible data evaluation for smaller deformations, all moment-rotation curves are parameterized using sigmoid functions. INTERPRETATION: In flexion-extension, the Transition® device provides the highest stiffening of the segment and the largest shift of the center of rotation. No shift in the center of rotation, and the smallest supporting effect on the segment is observed for axial rotation. In lateral bending, a mediate reduction of the range of motion is observed.

Clinical experiences with a PEEK-based dynamic instrumentation device in lumbar spinal surgery: 2 years and no more.

BACKGROUND: Dynamic spine implants were developed to prevent adjacent segment degeneration (ASD) and adjacent segment disease (ASDi). Purpose of this study was to investigate the clinical and radiological outcomes of "topping off" devices following lumbar spinal fusion procedure using a PEEK-based dynamic rod system. Moreover, this study focused on the hypothesis that "topping off" devices can prevent ASD. METHODS: This prospective nonrandomized study included patients with indication for single-level lumbar fusion and radiological signs of ASD without instability. The exclusion criteria were previous lumbar spine surgery and no sign of disc degeneration in the adjacent segment according to magnetic resonance imaging. All patients were treated with single-level lumbar interbody fusion and dynamic stabilization of the cranial adjacent segment. Patients underwent a clinical examination and radiographs preoperatively and at 1 and 2 years after surgery. Analyses were performed on clinical data collected with the German Spine Registry using the core outcome measure index (COMI) and visual analogue scale (VAS) scores for back and leg pain. RESULTS: A total of 22 patients (6 male and 16 female) with an average age of 57.6 years were included in the study; 20 patients completed the follow-up (FU). The average COMI score was 9.0 preoperatively, 4.2 at the 1-year FU, and 4.7 at the 2-year FU. The average preoperative VAS scores for back and leg pain were 7.7 and 7.1, respectively. At the 1-year FU, the scores were 4.25 for back pain and 2.2 for leg pain, and at the 2-year FU, the scores were 4.7 for back pain and 2.3 for leg pain. At FU, failure of the dynamic topping off implant material was verified in four cases, and ASD of the segment cranial to the topping off was confirmed in three cases. CONCLUSIONS: These results demonstrate significant improvements in clinical outcomes and pain reduction after lumbar spinal fusion with topping off at 2 years after surgery. However, the implant failed due to the high rate of implant failure and the development of ASD in the segment cranial to the dynamic stabilized segment.

The impact of obesity measured by outer abdominal fat on instability of the adjacent segments after rigid pedicle screw fixation.

Previous studies have shown coherence between obesity and higher rates of complications following spinal surgery. However, there is a lack of information about the influence of obesity and the mass of outer abdominal fat (OAF) on adjacent segment instability after spinal fusion surgery. Radiographs of 194 patients with spinal fusion surgery were assessed retrospectively. Radiographs were performed after surgery during two years' follow-up and signs of adjacent segment instability were documented. Patients were classified regarding their BMI and extent of OAF was assessed using CT at the umbilical level. In 20 patients (10.3%) instability of adjacent segments occurred during followup. In this cohort mean OAF was significantly thicker (28.07 mm) compared to the patients without instability (22.39) (P=0.038). A total of 45% of patients with instability showed OAF of more than 30 mm at time of intervention compared to 10% in those without signs of instability. There exists significant correlation between the extent of OAF and development of adjacent segment instability postoperatively. Thus, weight reduction before spinal surgery could potentially decrease risk of adjacent segment instability.

The use of the DTO™ hybrid dynamic device: a clinical outcome- and radiological-based prospective clinical trial.

BACKGROUND: The purpose of this study was to assess the radiological and clinical outcome parameters following lumbar hybrid dynamic instrumentation with the focus on the adjacent segment degeneration (ASD) and adjacent segment disease (ASDi). METHODS: In this prospective trial all patients presenting with degenerative changes to the lumbar spine have been included. Precondition was a stable adjacent level with/without degenerative alteration. The elected patients underwent a standardised fusion procedure with hybrid instrumentation (DTO™, Zimmer Spine Inc., Denver, USA). Patients' demographics have been documented and the follow-up visits were conducted after 6 weeks, and then stepwise after 6 up to 48 months. Each follow-up visit included assessment of quality of life and pain using specific questionnaires (COMI, SF-36, ODI) and the radiological evaluation with focus on the adjacent level alterations. RESULTS: At a mean follow up of 24 months an incidence of ASD with 10.91% and for ASDi with 18.18% has been observed. In 9% a conversion to standardised fusion was needed. There was a high rate of mechanical complication: (1) screw loosening (52.73%), (2) pedicle screw breakage (10.91%), and (3) rod breakage (3.64%) after a follow up of a maximum of 60 months. There were no significant difference of COMI, ODI and SF-36(v2) in comparison to all groups but all 55 patients showed a clinical improvement over the time. CONCLUSION: The dynamic hybrid DTO™ device is comparable to the long-term results after standardised fusion procedure, while a high rate of mechanical complication decreased the initial benefit. TRIAL REGISTRATION: This trial was registered at the ClinicalTrials Register ( #NCT03404232 , 2018/01/18, registered retrospectively).

Posterior Lumbar Interbody Fusion versus Dynamic Hybrid Instrumentation: A Prospective Randomized Clinical Trial.

OBJECTIVE: The purpose of this study was to assess the radiologic and clinical outcomes after lumbar fusion intervention and to compare the established posterior lumbar interbody fusion (PLIF) technique and dynamic hybrid instrumentation (topping off). METHODS: In this prospective randomized trial, all patients who presented with degenerative changes to the lumbar spine (L2-S1) were included and randomized in 2 groups: patients who underwent the 360°-fusion procedure in PLIF (group 1: control group) and those patients who underwent fusion surgery with additional hybrid instrumentation (Dynesys-Transition-Optima [Zimmer Spine Inc., Denver, Colorado, USA]) cranial to the rigid fixed segment (group 2: intervention group). Patients' demographics were documented and follow-up visits were conducted after 6 weeks and then stepwise after 6 up to 36 months. Each follow-up visit included assessment of quality of life and pain using specific questionnaires (Core Outcome Measurements Index, Short-Form 36, and Oswestry Disability Index) as well as radiologic evaluation with the focus on the adjacent level alteration. RESULTS: Fifteen patients per group met the inclusion criteria, and after 36 months, the loss to follow-up was 20%. At the maximum follow-up time, the overall risk for adjacent segment degeneration was substantial (i.e., 24.14%), independent of the surgical procedure. Material failure was observed in 17.24%. Although no significant difference was observed between both groups, all patients presented with postoperative improvement regarding the clinical scores. CONCLUSIONS: The present study cannot support the safety of dynamic hybrid devices in those cases if the reduction of adjacent segment degeneration is the main target, especially regarding the reported implant failure rates and the similar clinical outcomes between the both groups.

Incidence and Risk Factors for Facet Joint Violation in Open Versus Minimally Invasive Procedures During Pedicle Screw Placement in Patients with Trauma.

OBJECTIVE: A possible risk factor for premature facet joint degeneration or adjacent segment degeneration after surgical treatment of spine fractures is facet joint violation (FV) during insertion of pedicle screws. The aim of this study was to determine risk factors for FV in the thoracic and lumbar spine after minimally invasive screw insertion or open instrumentation (OI). METHODS: A retrospective analysis of all patients with spine fractures requiring posterior stabilization was performed. After patients were allocated to the thoracic/lumbar group, FV was defined as an involvement caused by the positioning of a pedicle screw and its severity as determined by computed tomography was assessed by using a customized scoring system. Gender, age, and body mass index as well as segmental facet joint angle and the instrumentation system used (side-loading [SL] vs. top-loading) were considered as individual factors. RESULTS: In total, 1099 pedicle screws were evaluated and an FV was identified in 433 instrumentations (39.0%). OI was used in 61.1% (n = 671) and an SL system was inserted in 45.0% (n = 494). In both, the thoracic (odds ratio [OR], 1.663; 95% confidence interval [CI], 1.119-2.472; P = 0.012) and the lumbar spine (OR, 0.494; 95% CI, 0.317-0.771; P = 0.002), OI was associated with a lower risk of FV. The violation rate was significantly higher when using a SL system (thoracic spine: OR, 1.822; 95% CI, 1.163-2.854; P = 0.009; lumbar spine: OR, 0.311; 95% CI, 0.203-0.477; P ≤ 0.001). CONCLUSIONS: FV is a common complication after thoracic and lumbar spine surgery. Although both, the SL instrumentation and a minimally invasive procedure increases its occurrence, the patient characteristics do not affect the rate of FV.

Computer tomography-based morphometric analysis of the cervical spine pedicles C3-C7.

BACKGROUND: Our aim was to examine the specific dimensions of cervical pedicles in a large Caucasian cohort on high dissolving CT scans. METHODS: A retrospective analysis of 100 cervical spine CT scans with a maximum slice thickness of 1 mm in axial, sagittal, and coronal reconstructions was performed. The pedicle axial length (PAL), inner and outer pedicle diameter (IPD/OPD), pedicle sagittal and transverse angle (PSA/PTA), pedicle height (PH), pedicle width (PW), and the cortical thickness (COT) at different margins were measured by two independent observers. A total of 1000 cervical pedicles (C3-C7) of 52 male (age 58 ± 17.47 years, height 177.97 ± 8.17 cm) and 48 female patients (age 57 ± 19.07 years, height 165.50 ± 7.44) were measured. RESULTS: Cortical thickness at the medial limitation of the pedicle was 1.77 ± 0.43 and 0.90 ± 0.36 mm at the lateral limitation (p < 0.001). The mean PAL ranged from 30.5 mm at C4 level to 35.3 mm at C6 level. PW and PAL were smaller in the female than in the male patients. The smallest values for PW were at C3 with 29.17% of males and 52.88% of females < 4.5 mm. The percentage of patients with PW < 4.5 mm decreased caudally with less than 10% of pedicles below C4 in male participants and below C6 in female participants. Mean PTA ranged from 34.6° to 48.02° peaking at C4 and C5 levels. No gender-specific difference was found for PTA and PSA (p ≥ 0.13). IPD and OPD were larger in males (p < 0.001), and body height correlated significantly with IPW (p ≤ 0.019) and OPW (p ≤ 0.003). The interrater reliability was very good for PW, PH, and IPD (0.84-0.86), good for OPD, PTA, and PSA (0.64-0.79), and moderate for PAL (0.54) and cortical thickness (0.44). CONCLUSIONS: Peculiarities of pedicle dimension of this central European cohort are comparable to morphometric studies in other ethnicities. Preoperative planning before cervical pedicle screw insertion on fine-cut CT scans demonstrates good interrater reliability for all important dimensions and angulations. More than half of female patients and almost a third of male patients had a PW of less than 4.5 mm at C3 level. Even though this percentage decreases caudally, pedicle screws might not be safe to insert in a noteworthy percentage of patients.