Thermographic assessment of skin temperature after lumbar spine surgery: Useful method for detection of wound complications? A pilot study.

BACKGROUND: Wound complications after lumbar spine surgery may result in prolonged hospitalization and increased morbidity. Early identification can trigger appropriate management. OBJECTIVE: The aim of this study was to investigate the efficacy of infrared-based wound assessment (FLIR) after lumbar spine surgery in the context of identifying wound healing disorders. METHODS: 62 individuals who underwent lumbar spine surgery were included. The immediate postoperative course was studied, and the patient's sex, age, body mass index (BMI), heart rate, blood pressure, body temperature, numeric rating scale for pain (NRS), C-reactive protein (CRP), leukocyte, and hemoglobin levels were noted and compared to thermographic measurement of local surface temperature in the wound area. RESULTS: Measurement of local surface temperature in the wound area showed a consistent temperature distribution while it was uneven in case of wound healing disorder. In this instance, the region of the wound where the wound healing disorder occured had a lower temperature than the surrounding tissue (p> 0.05). CONCLUSIONS: This study demonstrates the ongoing importance of clinical wound assessment for early detection of complications. While laboratory parameter measurement is crucial, FLIR may serve as a cost-effective supplemental tool in clinical wound evaluation. Patient safety risks appear minimal since local ST is measured without touch.

The projected increase of vertebral osteomyelitis in Germany implies a demanding challenge for future healthcare management of aging populations.

PURPOSE: Since an increase in the occurrence of native vertebral osteomyelitis (VO) is expected and reliable projections are missing, it is urgent to provide a reliable forecast model and make it a part of future health care considerations. METHODS: Comprehensive nationwide data provided by the Federal Statistical Office of Germany were used to forecast total numbers and incidence rates (IR) of VO as a function of age and gender until 2040. Projections were done using autoregressive integrated moving average model on historical data from 2005 to 2019 in relation to official population projections from 2020 to 2040. RESULTS: The IR of VO is expected to increase from 12.4 in 2019 to 21.5 per 100,000 inhabitants [95% CI 20.9-22.1] in 2040. The highest increase is predicted in patients over 75 years of age for both men and women leading to a steep increase in absolute numbers, which is fourfold higher compared to patients younger than 75 years. While the IR per age group will not increase any further after 2035, the subsequent increase is due to a higher number of individuals aged 75 years or older. CONCLUSIONS: Our data suggest that increasing IR of VO will seriously challenge healthcare systems, particularly due to demographic change and increasing proportions of populations turning 75 years and older. With respect to globally fast aging populations, future health care policies need to address this burden by anticipating limitations in financial and human resources and developing high-level evidence-based guidelines for prevention and interdisciplinary treatment.

Navigation versus fluoroscopy in minimalinvasive iliosacral screw placement.

INTRODUCTION: When needed operative treatment of sacral fractures is mostly performed with percutaneous iliosacral screw fixation. The advantage of navigation in insertion of pedicle screws already could be shown by former investigations. The aim of this investigation was now to analyze which influence iliosacral screw placement guided by navigation has on duration of surgery, radiation exposure and accuracy of screw placement compared to the technique guided by fluoroscopy. METHODS: 68 Consecutive patients with sacral fractures who have been treated by iliosacral screws were inclouded. Overall, 85 screws have been implanted in these patients. Beside of demographic data the duration of surgery, duration of radiation, dose of radiation and accuracy of screw placement were analyzed. RESULTS: When iliosacral screw placement was guided by navigation instead of fluoroscopy the dose of radiation per inserted screw (155.0 cGy*cm2 vs. 469.4 cGy*cm2 p < 0.0001) as well as the duration of radiation use (84.8 s vs. 147.5 s p < 0.0001) were significantly lower. The use of navigation lead to a significant reduction of duration of surgery (39.0 min vs. 60.1 min p < 0.01). The placement of the screws showed a significantly higher accuracy when performed by navigation (0 misplaced screws vs 6 misplaced screws-p < 0.0001). CONCLUSION: Based on these results minimal invasive iliosacral screw placement guided by navigation seems to be a safe procedure, which leads to a reduced exposure to radiation for the patient and the surgeon, a reduced duration of surgery as well as a higher accuracy of screw placement.

Increased stability due to symmetric cement volume in augmented pedicle screws? A biomechanical study.

Pedicle screw instrumentation has become "state of the art" in surgical treatment of many spinal disorders. Loosening of pedicle screws due to poor bone mineral density is a frequent complication in osteoporotic patients. As prevalence of osteoporosis and spinal disorders are increasing with an aging demographic, optimizing the biomechanical properties of pedicle screw constructions and therefore outcome after spinal surgery in osteoporotic patients is a key factor in future surgical therapy. Therefore, this biomechanical study investigated the stability of polymethylmethacrylate (PMMA)-augmented pedicle screw-rod constructions under a deviating distribution of PMMA applied to the instrumentation in osteoporotic human cadaveric vertebrae. We showed that PMMA-augmented pedicle screw-rod constructions tend to be more stable than those with non-augmented pedicle screws. Further, there appears to be a larger risk of screw loosening in unilateral augmented pedicle screws than in non-augmented, therefore a highly asymmetrically distributed PMMA should be avoided.

Does index-level pedicle screw instrumentation affect cage subsidence after vertebral body replacement? - A biomechanical study in human cadaveric osteoporotic specimens.

BACKGROUND: Vertebral body replacement is a common surgical procedure for treatment of disorders associated with spinal instability. Therefore, pedicle screws are usually inserted in adjacent vertebrae for stabilization of the posterior column, however, there is lack of evidence whether implantation of index-level pedicle screws is beneficial or not. This biomechanical study aims to investigate the effect of pedicle screw instrumentation on axial stability following vertebral body replacement. METHODS: Unstable fracture at L3 level was simulated in lumbar spines from six human cadaveric specimens. Then instrumentation was performed one level above / one level below index level in three specimens and further, three specimens were instrumented at index-level (L3) additionaly. Then we used a testing protocol for biomechanical evaluation of axial loading on human cadaveric lumbar spines until cage subsidence occurred. FINDINGS: Our results show that index-level instrumented spines endured significantly higher load until cage subsidence occurred compared to non-index-level instrumented specimens (p = 0.05). INTERPRETATION: Our results demonstrate pedicle screw instrumentation at index-level vertebra should be considered when possbile as it may have a protective effect against cage subsidence in patients undergoing vertebral body replacement surgery.

Patient-related risk factors and lifestyle factors for lumbar degenerative disc disease: a systematic review.

OBJECTIVE: Back pain is a very widespread disease pattern and is one of the most frequent causes for consultation of a physician in general. In most cases, discogenic changes are the pathomorphological correlate of back pain. Numerous risk factors have been identified for these degenerative changes, but the influence and significance of the risk factors remain unclear, which was the aim of this systematic review. METHODS: A systematic literature search of the commonly used Pubmed database was performed using specific MESH terms. Further selection of the included studies was performed according to the PRISMA scheme, taking into account scientific merit as well as the relation to the research question. RESULTS: A total of 111 studies out of 1035 found were finally included in the literature search. 134 risk factors for disc degeneration and disc herniation were identified. These were divided into (1) patient-specific risk factors (n░=░34), (2) radiological risk factors (n░=░31), (3) lifestyle risk factors (n░=░6), (4) workplace-related risk factors (n░=░12), (5) genetic risk factors (n░=░50), and (6) other risk factors (n░=░1). Non-adjustable risk factors were age >50 years (OR 1.7/year), female gender (OR 1.41), family disposition (OR 4.0), comorbidities like atherosclerosis (OR 2.24), arthritic changes in other joints (OR 3.1) and history of injuries of the back (OR 3.1). Adjustable factors were elevated BMI (OR 2.77), comorbidities like hypertension (OR 1.25), dyslipidemia (OR 1.26) and diabetes mellitus (OR 6.8), as well as lifestyle habits like smoking (OR 3.8). DISCUSSION: In summary, intervertebral disc degenerations and herniations represent multifactorial events whose risk factors can be partly influenced and partly not influenced. This systematic review highlights the current state of knowledge as a basis for creating patient-specific algorithms to calculate risk for the development or progression of degenerative disc changes and disc herniations.

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.

Postoperative Surgical Site Infections in Spine Surgery: Can the Duration of Surgery Predict the Pathogen Spectrum?

BACKGROUND/AIM: Surgical site infection (SSI) is a severe complication of spinal surgery, which typically results in prolonged length of hospital stay, an increased number of revision surgeries, re-hospitalizations, worse clinical functional outcomes, and increased healthcare costs. The aim of the present study was to analyse if the duration of surgery can predict the spectrum of pathogens causing SSI in orthopaedic spine surgery. PATIENTS AND METHODS: We conducted a retrospective study over a period of two years at the University Hospital of Cologne in which all patients with postoperative surgical site infections were included. In addition to descriptive characteristics (such as sex, age, BMI), the duration of the surgery, the administration of intra-operative antibiotics, the main diagnosis, the postoperative course of the infection parameters (CRP & WBC) and the responsible pathogens were analysed. RESULTS: A total of 75 patients were included with a median age of 64 years. The mean time of operation time was 131.52±70.91 min (range=23-285 min). The most frequently isolated germs in the postoperative blood culture were S. aureus (n=7), S. haemolyticus and S. hominis (n=2). There was a significant correlation between the duration of the primary surgical intervention and the postoperatively detected pathogens (p=0.002). CONCLUSION: A significant correlation was shown between the duration of surgery and the species of pathogens detected causing postoperative SSI. The use of perioperative antibiotics, the use of longer-lasting antibiotics or the repeated intravenous administration of prophylactic antibiotics should be evaluated.

Pedicle or lateral mass screws in Goel-Harms construct? A biomechanical analysis.

BACKGROUND: The use of the posterior arch of C1 as pedicle has shown beneficial stability regarding screw loosening, however, the C1 pedicle screw placement is challenging. Therefore, the study aimed to analyse the bending forces of the Harms construct used in fixation of C1/C2 when using pedicle screws compared to lateral mass screws. METHODS: Five cadaveric specimens with a mean age of 72 years at death and bone mineral density measuring for 512.4 Hounsfield Units (HU) on average were used. A custom-made biomechanical setup was used to test the specimens with a C1/C2 Harms construct each with the use of lateral mass screws and pedicle screws in sequence. Strain gauges were used to analyse the bending forces from C1 to C2 in cyclic axial compression (µm/m). All underwent cyclic biomechanical testing using 50, 75 and 100 N. FINDINGS: In all specimens, placement of lateral mass screws and pedicle screws was feasible. All underwent cyclic biomechanical testing. For the lateral mass screw, a bending of 142.04 µm/m at 50 N, 166.56 µm/m at 75 N and 188.54 µm/m at 100 N was measured. For the pedicle screws, bending force was slightly elevated with 165.98 µm/m at 50 N, 190.58 µm/m at 75 N and 195.95 µm/m at 100 N. However, bending forces did not vary significantly. In all measurements, no statistical significance was found when comparing pedicle screws and lateral mass screws. INTERPRETATION: The lateral mass screw used in the Harms Construct to stabilize C1/2 showed less bending forces, therefore the construct with lateral mass screws appears more stable in axial compression compared to the one with pedicle screws. However, bending forces did not vary significantly.

Management of Pathological Thoracolumbar Vertebral Fractures in Patients With Multiple Myeloma: Multidisciplinary Recommendations.

STUDY DESIGN: Mutlidisciplinary consensus recommendations for patients suffering from multiple myeloma (MM) involvement of the spinal column by the Spine Section of the German Association of Orthopaedic and Trauma Surgeons. OBJECTIVE: To provide a comprehensive multidisciplinary diagnostic and therapeutic approach and to summarize the current literature on the management of pathological thoracolumbar vertebral fractures in patients with multiple myeloma. METHODS: Multidisciplinary recommendations using a classical consensus process provided by radiation oncologists, medical oncologists, orthopaedic- and trauma surgeons. A narrative literature review of the current diagnostic and treatment strategies was conducted. RESULTS: Treatment decision has to be driven by a multidisciplinary team of oncologists, radiotherapists and spine surgeons. When considering surgery in MM patients, differing factors compared to other secondary spinal lesions have to be included into the decision process: probable neurological deterioration, the stage of the disease and prognosis, patient's general condition, localization and number of the lesions as well as patient's own wishes or expectations. Aiming to improve quality of life, the major goal of surgical treatment is to preserve mobility by reducing pain, secure neurological function and stability. CONCLUSION: The goal of surgery is primarily to improve quality of life by restoring stability and neurological function. Interventions with an increased risk of complications due to MM-associated immunodeficiency must be avoided whenever feasible to allow early systemic treatment. Hence, treatment decisions should be based on a multidisciplinary team that considers patient's constitution and prognosis.

Spondylodiscitis in Geriatric Patients: What Are the Issues?

STUDY DESIGN: Review article. OBJECTIVES: A review of literature on the treatment of pyogenic spondylodiscitis in geriatric patients was performed with the aim to give an overview about these special patients and a recommendation on necessary diagnostics as well as conservative and operative treatment options. METHODS: A systematic computerized literature search was done by the spondylodiscitis working group of the German Society for Orthopedics and Trauma Surgery. RESULTS: Spondylodiscitis has an increasing incidence by age with a peak at 75 years or older. The 1-year mortality without an appropriate treatment is with 15 to 20% extremely high. Pathogen detection is the essential diagnostic step and the basis for a sufficient antibiotic treatment. Geriatric patients have initially less elevated inflammatory parameters. Compared to younger patients. They have a longer length of hospital stay and take longer for CRP normalization. Even the outcome between conservative and operative treatment is comparable after one year. Patients with spinal instability, immobilizing pain, epidural abscess, and newly emerged neurological deficits should be considered for operative treatment. CONCLUSIONS: The treatment of geriatric patients with pyogenic spondylodiscitis must take into account that these patients usually have multiple comorbidities. The main goals are resistance-based antibiotics and the shortest possible time of immobilization of the patient.

Treatment and Outcome of Osteoporotic Thoracolumbar Vertebral Body Fractures With Deformation of Both Endplates With or Without Posterior Wall Involvement (OF 4): Short-Term Results from the Prospective EOFTT Multicenter Study.

STUDY DESIGN: Multicenter prospective cohort study. OBJECTIVE: To analyse therapeutical strategies applied to osteoporotic thoracolumbar OF 4 injuries, to assess related complications and clinical outcome. METHODS: A multicenter prospective cohort study (EOFTT) including 518 consecutive patients who were treated for an Osteoporotic vertebral compression fracture (OVCF). For the present study, only patients with OF 4 fractures were analysed. Outcome parameters were complications, Visual Analogue Scale, Oswestry Disability Questionnaire, Timed Up & Go test, EQ-5D 5L, and Barthel Index after a minimum follow-up of 6 weeks. RESULTS: A total of 152 (29%) patients presented with OF 4 fractures with a mean age of 76 years (range 41-97). The most common treatment was short-segment posterior stabilization (51%; hybrid stabilization in 36%). Mean follow up was 208 days (±131 days), mean ODI was 30 ± 21. Dorsoventral stabilized patients were younger compared to the other groups (P < .001) and had significant better TuG compared to hybrid stabilization (P = .049). The other clinical outcomes did not differ in the therapy strategies (VAS pain: P = 1.000, ODI: P > .602, Barthel: P > .252, EQ-5D 5L index value: P > .610, VAS-EQ-5D 5L: P = 1.000). The inpatient complication rate was 8% after conservative and 16% after surgical treatment. During follow-up period 14% of conservatively treated patients and 3% of surgical treated patients experienced neurological deficits. CONCLUSIONS: Conservative therapy of OF 4 injuries seems to be viable option in patients with only moderate symptoms. Hybrid stabilization was the dominant treatment strategy leading to promising clinical short-term results. Stand-alone cement augmentation seems to be a valid alternative in selected cases.

Treatment and Outcome of Osteoporotic Thoracolumbar Vertebral Fractures With Anterior or Posterior Tension Band Failure (OF 5): Short-Term Results From the Prospective EOFTT Multicenter Study.

STUDY DESIGN: Subgroup analysis of a multicenter prospective cohort study. OBJECTIVE: To analyse surgical strategies applied to osteoporotic thoracolumbar osteoporotic fracture (OF) 5 injuries with anterior or posterior tension band failure and to assess related complications and clinical outcome. METHODS: A multicenter prospective cohort study (EOFTT) was conducted at 17 spine centers including 518 consecutive patients who were treated for an osteoporotic vertebral fracture (OVF). For the present study, only patients with OF 5 fractures were analysed. Outcome parameters were complications, Visual Analogue Scale (VAS), Oswestry Disability Questionnaire (ODI), Timed Up & Go test (TUG), EQ-5D 5L, and Barthel Index. RESULTS: In total, 19 patients (78 ± 7 years, 13 female) were analysed. Operative treatment consisted of long-segment posterior instrumentation in 9 cases and short-segment posterior instrumentation in 10 cases. Pedicle screws were augmented in 68 %, augmentation of the fractured vertebra was performed in 42%, and additional anterior reconstruction was done in 21 %. Two patients (11 %) received short-segment posterior instrumentation without either anterior reconstruction or cement-augmentation of the fractured vertebra. No surgical or major complications occurred, but general postoperative complications were observed in 45%. At a follow-up of mean 20 ± 10 weeks (range, 12 to 48 weeks), patients showed significant improvements in all functional outcome parameters. CONCLUSIONS: In this analysis of patients with type OF 5 fractures, surgical stabilization was the treatment of choice and lead to significant short-term improvement in terms of functional outcome and quality of life despite a high general complication rate.

Geriatric Odontoid Fractures: Treatment Algorithms of the German Society for Orthopaedics and Trauma Based on Expert Consensus and a Systematic Review.

STUDY DESIGN: Systematic review/expert consensus. OBJECTIVES: Fractures of the axis represent the most frequent injury of the spine in elderly patients. Both, operative and non-operative treatment are associated with a high rate of complications and mortality. The aim of this article was to summarize the current literature on the management of odontoid fractures in geriatric patients and to weigh it based on an expert consensus process. METHODS: In a joint consensus process, members of the Spine Section of the German Orthopaedic and Trauma Society (DGOU) aimed to formulate recommendations for the diagnostic workup and treatment of odontoid fractures in geriatric patients. Based on the previously published recommendations, this article is an updated version with incorporating a systematic review of the recent literature. RESULTS: Based on the new data available, the recommendations established in the initial consensus process were adapted. CONCLUSIONS: Computed tomography represents the diagnostic standard for patients with suspected injuries of the upper cervical spine. Anderson/D'Alonzo odontoid fractures type 1, non-displaced type 2, and type 3 can be treated conservatively. Even non-unions do not necessarily result in poor clinical outcome. In Anderson/D'Alonzo type 2 fractures, surgical therapy offers the advantage of relatively safe osseous healing with no increased complication rate even in elderly patients and can thus be recommended. In very high aged patients, however, a case-by-case decision should be made. When surgical stabilization of osteoporotic odontoid fractures is indicated, posterior techniques are biomechanically advantageous and can be considered the standard.

Combined Odontoid (C2) and Atlas (C1) Fractures in Geriatric Patients: A Systematic Review and Treatment Recommendation.

STUDY DESIGN: Systematic review. OBJECTIVE: The aim of this study was to conduct a systematic overview of the pathogenesis and the treatment options of combined odontoid and atlas fractures in geriatric patients. METHODS: This review is based on articles retrieved by a systematic search in the PubMed and Web of Science databases for articles published until February 2021 dealing with combination fractures of C1 and C2 in geriatric patients. RESULTS: Altogether, 438 articles were retrieved from the literature search. A total of 430 articles were excluded. The remaining eight original articles were included in this systematic review depicting the topics pathogenesis, non-operative treatment, posterior approach, and anterior approach. The overall level of evidence of the studies is low. CONCLUSION: Combined odontoid and atlas fractures in the geriatric population are commonly caused by simple falls and seem to be associated with atlanto-odontoid osteoarthritis. Non-operative treatment with a cervical orthosis is a feasible treatment option in the majority of patients with stable C2 fractures. In case of surgery posterior C1 and C 2 stabilization and anterior triple or quadruple screw fixation are possible techniques. Some patients may also deserve an occipito-cervical fusion. A possible treatment algorithm is proposed.

Mediating Medical Comorbidities in Geriatric Patients Undergoing Surgery for OVCF: From Preoperative Screening to Risk and Outcomes Optimization.

OBJECTIVES: Osteoporotic vertebral compression fractures (OVCF) are a common increasing entity in elderly patients and represent a tremendous economic burden. Surgical treatment is related to high complication rates and little is known about patient-specific and internal risk factors associated with poor clinical results. METHODS: We carried out a comprehensive, systematic literature search according to the PRISMA checklist and algorithm. Risk factors for perioperative complications, for early inpatient readmission, for the duration of the hospital stay, the hospital mortality, the total mortality and the clinical result were analyzed. RESULTS: A total of 739 potentially usable studies were identified. After considering all inclusion and exclusion criteria, 15 studies with 15,515 patients were included. Non-adjustable risk factors were age >90 years (OR 3.27), male gender (OR 1.41), BMI less than 18.5 kg/m2 (OR 3.97), ASA score >3 (OR 2.7), activity of daily live (ADL) (OR 1.52), dependence (OR 5.68), inpatient admission status (OR 3.22), Parkinson disease (OR 3.63) and disseminated cancer (OR 2.98). Adjustable factors were insufficient kidney function (GFR <60 mL/min, and Creatinine Clearance below 60 mg/dl) (OR 4.4), nutrition status (hypalbuminemia (<3.5 g/dl)), liver function (OR 8.9) and further cardiac and pulmonary comorbidities. DISCUSSION: We identified a couple of non-adjustable risk factors, which should be considered preoperatively in terms of risk assessment. However, even more important were adjustable factors that can be influenced preoperatively. In conclusion, we recommend a perioperative interdisciplinary cooperation, especially with geriatricians, to achieve the best possible clinical results in geriatric patients undergoing surgery for OVCF.

Clinical Evaluation of the Osteoporotic Fracture Treatment Score (OF-Score): Results of the Evaluation of the Osteoporotic Fracture Classification, Treatment Score and Therapy Recommendations (EOFTT) Study.

STUDY DESIGN: Multicenter prospective cohort study. OBJECTIVE: The study aims to validate the recently developed OF score for treatment decisions in patients with osteoporotic vertebral compression fractures (OVCF). METHODS: This is a prospective multicenter cohort study (EOFTT) in 17 spine centers. All consecutive patients with OVCF were included. The decision for conservative or surgical therapy was made by the treating physician independent of the OF score recommendation. Final decisions were compared to the recommendations given by the OF score. Outcome parameters were complications, Visual Analogue Scale, Oswestry Disability Questionnaire, Timed Up & Go test, EQ-5D 5 L, and Barthel Index. RESULTS: In total, 518 patients (75.3% female, age 75 ± 10) years were included. 344 (66%) patients received surgical treatment. 71% of patients were treated following the score recommendations. For an OF score cut-off value of 6.5, the sensitivity and specificity to predict actual treatment were 60% and 68% (AUC .684, P < .001). During hospitalization overall 76 (14.7%) complications occurred. The mean follow-up rate and time were 92% and 5 ± 3.5 months, respectively. While all patients in the study cohort improved in clinical outcome parameters, the effect size was significantly less in the patients not treated in line with the OF score's recommendation. Eight (3%) patients needed revision surgery. CONCLUSIONS: Patients treated according to the OF score's recommendations showed favorable short-term clinical results. Noncompliance with the score resulted in more pain and impaired functional outcome and quality of life. The OF score is a reliable and save tool to aid treatment decision in OVCF.

Is human bone matrix a sufficient augmentation method revising loosened pedicle screws in osteoporotic bone? - A biomechanical evaluation of primary stability.

INTRODUCTION: Despite good screw anchorage and safe screw trajectory, screw loosening occurs in several cases, especially in osteoporotic individuals. The aim of this biomechanical analysis was to evaluate the primary stability of revision screw placement in individuals with reduced bone quality. Therefore, revision via enlarged diameter screws was compared to the use of human bone matrix as augmentation to improve the bone stock and screw coverage. METHODS: 11 lumbar vertebral bodies from cadaveric specimens with a mean age of 85.7 years (± 12.0 years) at death were used. 6.5 mm diameter pedicle screws were inserted in both pedicles and hereafter loosened using a fatigue protocol. Screws were revised inserting a larger diameter screw (8.5 mm) in one pedicle and a same diameter screw with human bone matrix augmentation in the other pedicle. The previous loosening protocol was then reapplied, comparing maximum load and cycles to failure between both revision techniques. Insertional torque was continuously measured during insertion of both revision screws. FINDINGS: The number of cycles and the maximum load until failure were significantly greater in enlarged diameter screws than in augmented screws. The enlarged screws' insertional torque was also significantly higher than of the augmented screws. INTERPRETATION: Human bone matrix augmentation does not reach the same ad-hoc fixation strength as enlarging the screw's diameter by 2 mm and is therefore biomechanically inferior. Regarding the immediate stability, a thicker screw should therefore be prioritised.

Correlation between kidney function and mortality in pyogenic spondylodiscitis: the glomerular filtration rate (GFR) as new predictive parameter?

OBJECTIVE: Pyogenic spondylodiscitis is a severe medical condition, often requiring surgical intervention. Numerous risk factors are known, such as obesity, neurological impairment and old age. In-hospital mortality remains high, therefore other factors may be contributing to the increased mortality. To evaluate kidney function as a risk factor for increased morbidity of pyogenic spondylodiscitis, the glomerular filtration rate (GFR) was correlated with the patients' clinical course. MATERIALS AND METHODS: We retrospectively reviewed the cases of 366 patients and 255 were included for analysis. Clinical, laboratory and surgical data were recorded with a minimum follow-up of three months. For clinical outcome measurement, mortality, length of stay and perioperative complications were analysed. RESULTS: The study included 255 patients (173 men, 82 women; mean age 66.3 years). Patients with a GFR < 59 mL/min spent an average of 5 days longer in the hospital than those with a GFR ≥ 60 mL/min (p = 0.071). The mortality rate increased significantly with a decrease in GFR: A GFR of 30-59 mL/min had a mortality rate of 17.6%, whereas a GFR of < 29 mL/min had one of 30.4% (p = 0.003). Patients with impaired GFR showed an increased rate of postoperative complications (OR 4.7 p = 0.002) and higher rate of intensive care unit (ICU) stay (OR 8.7 p = < 0.001). DISCUSSION: Preoperative GFR values showed a significant correlation with in-hospital mortality in patients with spondylodiscitis, when graded according to the KDIGO stages. Furthermore, a GFR of < 29 ml/mL contributes to a longer ICU stay, postoperative complications and a longer total hospital stay. Therefore, the preoperative GFR could be a marker of kidney function and as a valuable predictive risk factor regarding the clinical in-hospital course of patients suffering from pyogenic spondylodiscitis.

Projections From Surgical Use Models in Germany Suggest a Rising Number of Spinal Fusions in Patients 75 Years and Older Will Challenge Healthcare Systems Worldwide.

BACKGROUND: Spinal fusion is a well-established procedure in the treatment of degenerative spinal diseases. Previous research shows that the use of this operative treatment has been growing in recent decades in industrialized countries and has become one of the most cost-intensive surgical procedures. It seems that in some countries such as Germany-with its large, industrialized, European population-this increase is mainly driven by demographic changes with low fertility rates, increasing life expectancy, and an aging population. Based on current projections, however, Germany faces a population trend that many other countries are likely to follow within a few decades. An increasingly shrinking and aging working population may eventually put the healthcare system under enormous pressure, with greater demands for spinal fusions and associated higher costs. Thus, we aimed to provide reliable projections regarding the future demand for posterior spinal fusion procedures including age- and gender-related trends up to 2060, which will be necessary for future resource planning and possible improvements in actual treatment strategies. QUESTIONS/PURPOSES: (1) How is the use of posterior spinal fusions in Germany expected to change from 2019 through 2060, if currents trends continue? (2) How is the use of posterior spinal fusions in Germany expected to change depending on patients' age and gender during this time period? METHODS: Comprehensive nationwide data provided by the Federal Statistical Office, the official institution for documenting all data on operations and procedures performed in Germany, were used to quantify posterior spinal fusion rates as a function of calendar year, age, and gender. Because there is a lack of evidence regarding future trends in the use of posterior spinal fusions, an autoregressive integrated moving average model on historical procedure rates from 2005 to 2019 in relation to official population projections from 2020 to 2060 was chosen to forecast future absolute numbers and incidence rates of this procedure in Germany. Long-term forecasting is more prone to unexpected disruptions than forecasting over short-term periods; however, longer spans facilitate estimates of how trends may challenge future healthcare systems if those trends continue, and thus are useful for research and planning. RESULTS: The incidence rate of posterior spinal fusion was projected to increase by approximately 83% (95% CI 28% to 139%) to 102% per 100,000 inhabitants (95% CI 71% to 133%) in 2060, with a 1.3-fold higher rate of women undergoing surgery in terms of absolute numbers. The highest increase identified by the model occurred in patients 75 years and older with 38,974 (95% CI 27,294 to 50,653) posterior spinal fusions in 2060, compared with 14,657 in 2019. This trend applied for both women and men, with a 246% (95% CI 138% to 355%) increase in the total number of posterior spinal fusions for women 75 years and older and a 296% (95% CI 222% to 370%) increase for men 75 years and older. At the same time, posterior spinal fusions in all age groups younger than 55 years were projected to follow a constant or even negative trend up to 2060. CONCLUSION: Our findings suggest that increasing use of posterior spinal fusion, particularly in patients 75 years and older, will challenge healthcare systems worldwide if current trends persist. This study may serve as a model for many other industrialized countries facing similar demographic and procedure-specific developments in the future. This emphasizes the need to focus on frailty research as well as appropriate financial and human resource management. Effective perioperative medical management, multidisciplinary treatment, and interinstitutional protocols are warranted, especially in older patients as we attempt to manage these trends in the future. LEVEL OF EVIDENCE: Level III, economic and decision analysis.