Bone density of the cervical, thoracic and lumbar spine measured using Hounsfield units of computed tomography - results of 4350 vertebras.

INTRODUCTION: The assessment of bone density has gained significance in recent years due to the aging population. Accurate assessment of bone density is crucial when deciding on the appropriate treatment plan for spinal stabilization surgery. The objective of this work was to determine the trabecular bone density values of the subaxial cervical, thoracic and lumbar spine using Hounsfield units. MATERIAL AND METHODS: Data from 200 patients who underwent contrast-enhanced polytrauma computed tomography at a maximum care hospital over a two-year period were retrospectively analyzed. HUs were measured with an elliptical measurement field in three different locations within the vertebral body: below the upper plate, in the middle of the vertebral body, and above the base plate. The measured Hounsfield units were converted into bone density values using a validated formula. RESULTS: The mean age of the patient collective was 47.05 years. Mean spinal bone density values decreased from cranial to caudal (C3: 231.79 mg/cm3; L5: 155.13 mg/cm3; p < 0.001), with the highest values in the upper cervical spine. Bone density values generally decreased with age in all spinal segments. There was a clear decrease in values after age 50 years (p < 0.001). CONCLUSIONS: In our study, bone density decreased from cranial to caudal with higher values in the cervical spine. These data from the individual spinal segments may be helpful to comprehensively evaluate the status of the spine and to design a better preoperative plan before instrumentation.

Muscle activity and rehabilitation in spinal stenosis (MARSS) after conservative therapy and surgical decompression with or without fusion: Protocol for a partially randomized patient preference trial on rehabilitation timing.

Background: Patients affected by lumbar spinal stenosis (LSS) suffer from a multifactorial degeneration of the lumbar spine resulting in narrowing of the neuroforamina and spinal canal, leading to various functional limitations. It remains unclear whether LSS patients after surgery would benefit from early post-operative rehabilitation, or if a delayed rehabilitation would be more advantageous. The purpose of this partially randomized patient preference trial is to evaluate the impact of post-operative rehabilitation timing as well as surgical intervention type on psychometric properties and functional outcomes in patients with LSS. Methods: Data for this patient preference trial are collected before and after surgical (decompression only or decompression and fusion) and rehabilitative interventions as well as six, 12 and 24 months after completing rehabilitation. The study participants are patients diagnosed with LSS who are at least 18 years old. After a medical check-up, participants will complete patient-reported outcome measures (PAREMO-20, SIBAR, FREM-8, SF-12, SFI, ODI) and different functional assessments (functional reach test, loaded reach test, handgrip strength, standing balance control, 6-min walk test). Ethics and dissemination: The results of this study will be published through peer-reviewed publications and scientific contributions at national and international conferences. This research has been approved by the Institutional Review Board of Martin Luther University Halle-Wittenberg (reference number: 2022-128).

Objective Assessment of Syndesmosis Stability Using the Hook Test.

The hook test is a widely used intraoperative method for assessing syndesmosis stability. However, there are no recommendations regarding the force required to perform this test. Furthermore, the reliability of the test is unclear. Ten experienced surgeons performed hook tests on a cadaver bone model. The applied forces were recorded in a blinded manner. In addition, standardized hook tests with defined forces (50, 80, and 100 N) were performed on 10 pairs of cadaver lower legs and the syndesmosis was sequentially destabilized. Diastasis of the syndesmosis was recorded using an optical 3D camera system. A median force of 81 N (Range: 50 N-145 N) was applied. A proportion of 82% of the tests showed a force < 100 N. The data showed good intraraterreliability and poor interraterreliability. In the standardized investigation of the hook test on the cadaver bone model, both the force and the instability of the syndesmosis had a significant influence on the syndesmosis diastasis. Nevertheless, even with maximum instability of the syndesmosis, diastasis > 2 mm could only be measured in 12 of the 19 evaluable specimens. The widely used hook test shows a high variability when performed in practice. Even in a standardized manner, the hook test cannot detect a relevant syndesmosis injury.

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.

Fibula Nail versus Locking Plate Fixation-A Biomechanical Study.

In the treatment of ankle fractures, complications such as wound healing problems following open reduction and internal fixation are a major problem. An innovative alternative to this procedure offers a more minimally invasive nail stabilization. The purpose of this biomechanical study was to clarify whether this method was biomechanically comparable to the established method. First, the stability (range of motion, diastasis) and rotational stiffness of the native upper ankle were evaluated in eight pairs of native geriatric specimens. Subsequently, an unstable ankle fracture was created and fixed with a locking plate or a nail in a pairwise manner. The ankles showed significantly less stability and rotational stiffness properties after nail and plate fixations than the corresponding native ankles (p < 0.001 for all parameters). When comparing the two methods, both showed no differences in their range of motion (p = 0.694) and diastasis (p = 0.166). The nail also presented significantly greater rotational stiffness compared to the plate (p = 0.001). However, both fixations remained behind the native stability and rotational stiffness. Due to the comparable biomechanical properties of the nail and plate fixations, an early weight-bearing following nail fixation should be assessed on a case-by-case basis considering the severity of fractures.

Georg Schmorl prize of the German spine society (DWG) 2022: current treatment for inpatients with osteoporotic thoracolumbar fractures-results of the EOFTT study.

AIM: Osteoporotic thoracolumbar fractures are of increasing importance. To identify the optimal treatment strategy this multicentre prospective cohort study was performed. PURPOSE: Patients suffering from osteoporotic thoracolumbar fractures were included. Excluded were tumour diseases, infections and limb fractures. Age, sex, trauma mechanism, OF classification, OF-score, treatment strategy, pain condition and mobilization were analysed. METHODS: A total of 518 patients' aged 75 ± 10 (41-97) years were included in 17 centre. A total of 174 patients were treated conservatively, and 344 were treated surgically, of whom 310 (90%) received minimally invasive treatment. An increase in the OF classification was associated with an increase in both the likelihood of surgery and the surgical invasiveness. RESULTS: Five (3%) complications occurred during conservative treatment, and 46 (13%) occurred in the surgically treated patients. 4 surgical site infections and 2 mechanical failures requested revision surgery. At discharge pain improved significantly from a visual analogue scale score of 7.7 (surgical) and 6.0 (conservative) to a score of 4 in both groups (p < 0.001). Over the course of treatment, mobility improved significantly (p = 0.001), with a significantly stronger (p = 0.007) improvement in the surgically treated patients. CONCLUSION: Fracture severity according to the OF classification is significantly correlated with higher surgery rates and higher invasiveness of surgery. The most commonly used surgical strategy was minimally invasive short-segmental hybrid stabilization followed by kyphoplasty/vertebroplasty. Despite the worse clinical conditions of the surgically treated patients both conservative and surgical treatment led to an improved pain situation and mobility during the inpatient stay to nearly the same level for both treatments.

[Value of routine transpedicular biopsies in kyphoplasty and vertebroplasty for vertebral compression fractures : A survey among 250 spine surgeons]. / Stellenwert der transpedikulären Biopsie bei Kypho- und Vertebroplastien von Wirbelkörperfrakturen : Eine Umfrage unter 250 Wirbelsäulenchirurgen.

BACKGROUND: Transpedicular cement augmentation is an established therapeutic option in the treatment of pathologic compression fractures of the spine. In addition to osteoporosis, underlying metastatic diseases or, more rarely, a primary bone tumor are recurrent causes of vertebral compression fractures without adequate trauma. OBJECTIVE: To obtain a current opinion among spine surgeons in Germany, Switzerland, and Austria on the value of transpedicular biopsy during kyphoplasty and vertebroplasty of vertebral body fractures. MATERIAL AND METHODS: A web-based (UmfrageOnline®) questionnaire with 11 questions was created and sent to the email distribution lists of the German Spine Society (DWG), the Austrian Society for Spine Surgery (spine.at), and the Swiss Society for Spinal Surgery (SGS), as well as to the email distribution list of the Spine Section of the German Society for Orthopedics and Trauma Surgery (DGOU). RESULTS: Of a total of 2675 spine surgeons contacted 250 (9.3%) responded to the survey. Approximately one third (29.8%) of respondents regularly perform a transpedicular biopsy with each kyphoplasty or vertebroplasty. Reasons cited for biopsy were image morphology (79.7%) or history of suspected (66.0%) or present (71.4%) tumor disease. Reasons cited against routine biopsy were the associated costs and the limited informative value of the biopsies obtained. DISCUSSION: Nearly one third of the spine surgeons surveyed regularly perform a transpedicular biopsy with each kyphoplasty or vertebroplasty. Almost all respondents perform biopsies at least when there is an imaging morphologic suspicion of tumor disease or tumor disease is known or suspected based on risk factors. Future studies need to further clarify the cost-effectiveness of transpedicular biopsy.

Perioperative outcome of minimally invasive stabilisation of bilateral fragility fractures of the sacrum: a comparative study of bisegmental transsacral stabilisation versus spinopelvic fixation.

PURPOSE: Pelvic fragility fractures have steadily risen over the past decades. The primary treatment goal is the fastest possible mobilisation. If conservative therapy fails, surgical fixation is a promising approach. This study compares the outcome of bisegmental transsacral stabilisation (BTS) and spinopelvic fixation (SP) as minimally invasive techniques for bilateral fragility fractures of the sacrum (BFFS). METHODS: We performed a prospective, non-randomised, case-controlled study. Patients were included if they remained bedridden due to pain despite conservative treatment. Group assignment depended on sacral anatomy and fracture type. The outcome was estimated by blood loss calculation, cut-seam time, fluoroscopy time, complications, duration of stay at the intensive/intermediate care unit (ICU/IMC), and total inpatient stay. The mobility level at discharge was recorded. RESULTS: Seventy-three patients were included (SP: 49, BTS: 24). There was no difference in blood loss (BTS: 461 ± 628 mL, SP: 509 ± 354 mL). BTS showed a significantly lower cut-seam time (72 ± 23 min) than SP (94 ± 27 min). Fluoroscopy time did not differ (BTS: 111 ± 61 s vs. 103 ± 45 s). Thirteen percent of BTS and 16% of SP patients required ICU/IMC stay (BTS: 0.6 ± 1.8 days, SP: 0.5 ± 1.5 days) during inpatient stay (BTS: 9 ± 4 days, SP: 8 ± 3 days). Fourteen patients suffered from urinary tract infections (BTS: 8%; SP: 25%). In-patient mortality was low (BTS: 4.2%, SP: 4.1%). At discharge, the BTS group was almost back to the initial mobility level. In SP patients, mobility was significantly lower than before complaints (p = 0.004). CONCLUSION: Both methods allow early mobilization of BFFS patients. Blood loss can be kept low. Hence, transfusion requirement is correspondingly low. The IMC/ICU and the total inpatient stay are lower than reported in the literature. Both BTS and SP can be recommended as safe and low-complication methods for use in BFFS patients. BTS is superior to SP with respect to surgery duration and level of mobility at discharge.

Concomitant injuries in patients with thoracic vertebral body fractures-a systematic literature review.

PURPOSE: The aim of this study was to give a systematic overview over the rate and location of concomitant injuries, the probability of suffering from neurological deficits, and to give evidence of the timing of surgery in severely injured patients with unstable thoracic vertebral body fractures. METHODS: This review is based on articles retrieved by a systematic search in the PubMed and Web of Science database for publications up to November 2020 dealing with unstable fractures of the mid-thoracic spine. RESULTS: Altogether, 1109 articles were retrieved from the literature search. A total of 1095 articles were excluded. Thus, 16 remaining original articles were included in this systematic review depicting the topics timing of surgery in polytraumatized patients, outcome neurologic deficits, and impact of concomitant injuries. The overall level of evidence of the vast majority of studies is low. CONCLUSION: The evidence of the available literature is low. The cited studies reveal that thoracic spinal fractures are associated with a high number of neurological deficits and concomitant injuries, particularly of the thoracic cage and the lung. Thereby, diagnostic algorithm should include computer tomography of the whole thoracic cage if there is any clinical sign of concomitant injuries. Patients with incomplete neurologic deficits benefit from early surgery consisting of decompression and long-segmental stabilization.

[Local spinal profile following operative treatment of thoracolumbar and lumbar fractures : Impact of reduction technique and bone quality]. / Lokales Wirbelsäulenprofil nach operativer Behandlung thorakolumbaler und lumbaler Frakturen : Einfluss von Repositionstechnik und Knochenqualität.

BACKGROUND: The goal of surgery for spinal injuries is fracture reduction, fixation and stable healing in a physiological position. Several open and minimally invasive surgical techniques are available. OBJECTIVE: The extent of open reduction and the fixation potential achieved by the AOSpine (AT) and Kluger (KT) techniques were compared. The influence of fracture morphology, age, sex, and bone quality on fracture reduction and secure fixation was investigated. MATERIAL AND METHODS: In this monocentric retrospective cohort study data of patients with traumatic thoracolumbar and lumbar fractures treated by AT or KT were analyzed. The bisegmental kyphotic angle (bGDW) of each injured spinal segment was determined. Normal bGDW values were extrapolated from the literature. The change of bGDW over time was analyzed under consideration of the bone quality in Hounsfield units (HU), injury severity according to the AOSpine classification, gender and age of patients. RESULTS: A total of 151 data sets were evaluated. The AT and KT methods achieved a similar extent of reduction (AT 10 ± 6°, KT 11 ± 8°; p = 0.786). In follow-up a mean reduction loss of -5 ± 4° was seen. The technique had no influence on this (p = 0.998). The fracture morphology just managed to achieve a significant influence (p = 0.043). Low HU correlated significantly but weakly with lower extent of reduction (r = 0.241, p < 0.003) and greater reduction loss (r = 0.272, p < 0.001). In the age group 50-65 years 21% of men and 43% of women had bone quality of < 110 HU. Age and HU were significantly correlated (r = -0.701, p < 0.001). CONCLUSION: The AT and KT are equivalent in terms of reduction and secure fixation properties. The high proportion of male and female patients with HU < 110 in the age group under 65 years and the influence on reduction and secure fixation emphasize the need for preoperative bone densitometry.

Multicenter evaluation of therapeutic strategies of inpatients with osteoporotic vertebral fractures in Germany.

PURPOSE: The aim of this study was to assess therapeutic strategies of inpatients with osteoporotic thoracolumbar fractures (OTF) in Germany. METHODS: Prospective multi-center study including 16 German-speaking trauma centers over a period of 7 months. All inpatients with OTF were included. Radiological and clinical data on admission and treatment modalities were assessed. RESULTS: Seven hundred and seven (99.3%) out of 712 included patients (73.3% female) could be evaluated. Mean age was 75 years (30-103). 51.3% could not remember any traumatic incident. Fracture distribution was from T2 to L5 with L1 (19%) most commonly affected. According to the Magerl classification type A1 (52.1%) and A3 (42.7%) were most common. B and C type injuries (2.6%) and neurological deficits (3.1%) were rare. Previous progression of vertebral deformation was evident in 34.4% of patients and related to t score below - 3 (Odds ratio 1.9661). Patients presented with anticoagulation medication (15.4%), dementia (13%), and ASA score > 3 (12.4%) frequently. 82.3% of patients complained of pain > 4 on VAS, 37% could not be mobilized despite pain medication according to grade II WHO pain ladder. 81.6% received operative treatment. Kyphoplasty (63.8%) and hybrid stabilization including kyphoplasty with (14.4%) or without screw augmentation (7.6%) were the techniques most frequently used. Invasiveness of treatment increased with degree of instability. CONCLUSIONS: OTF are mostly type A compression fractures. Patients suffer from severe pain and immobilization frequently. Progression of deformity is correlated to t score below - 3. Treatment of inpatients is mainly surgical, with kyphoplasty followed by hybrid stabilization as commonly used techniques.

Progressive instability of bilateral sacral fragility fractures in osteoporotic bone: a retrospective analysis of X-ray, CT, and MRI datasets from 78 cases.

PURPOSE: The pathogenetic mechanism, progression, and instability in geriatric bilateral fragility fractures of the sacrum (BFFSs) remain poorly understood. This study investigated the hypothesis of sequential BFFS progression by analysing X-ray, computed tomography (CT), and magnetic resonance imaging (MRI) datasets. METHODS: Imaging data from 78 cases were retrospectively analysed. Fractures were categorized using the CT-based Fragility Fractures of the Pelvis classification. MRI datasets were analysed to detect relevant fracture location information. The longitudinal sacral fracture was graded as stage 1 (bone oedema) on MRI, stage 2 (recent fracture), stage 3 (healing fracture), or stage 4 (non-union) on CT. Ligamentous avulsions at the L5 transverse process and iliac crest were also captured. RESULTS: Contralateral sacral lesions were only recognized by initial bone oedema on MRI in 17/78 (22%) cases. There were 22 cases without and 56 cases with an interconnecting transverse fracture component (TFC) [between S1/S2 (n = 39) or between S2/S3 (n = 17)]. With 30/78 patients showing bilateral fracture lines at different stages (1/2: n = 13, 2/3: n = 13, 1/3: n = 4) and 38 at similar stages, Wilcoxon tests showed a significant stage difference (p < 0.001). Forty cases had a coexistent L5 transverse process avulsion, consistent with a failing iliolumbar ligament. Analysis of variance revealed significant increases in ligamentous avulsions with higher fracture stages (p < 0.001). CONCLUSION: Our results support the hypothesis of stagewise BFFS progression starting with unilateral sacral disruption followed by a contralateral lesion. Loss of sacral alar support leads to a TFC. Subsequent bone disruption causes iliolumbar ligament avulsion. MRI is recommended to detect bone oedema.

Biomechanics and clinical outcome after posterior stabilization of mid-thoracic vertebral body fractures: a systematic literature review.

PURPOSE: The aim of this review is to systematically screen the literature for clinical and biomechanical studies dealing with posterior stabilization of acute traumatic mid-thoracic vertebral fractures in patients with normal bone quality. METHODS: This review is based on articles retrieved by a systematic search in the PubMed and Web of Science database for publications up to December 2018 dealing with the posterior stabilization of fractures of the mid-thoracic spine. RESULTS: Altogether, 1012 articles were retrieved from the literature search. A total of 960 articles were excluded. A total of 16 articles were dealing with the timing of surgery in polytraumatized patients, patients suffering of neurologic deficits after midthoracic fractures, and the impact of concomitant thoracic injuries and were excluded. Thus, 36 remaining original articles were included in this systematic review depicting the topics biomechanics, screw insertion, and outcome after posterior stabilization. The overall level of evidence of the vast majority of studies is low. CONCLUSION: High quality studies are lacking. Long-segmental stabilization is indicated in unstable midthoracic fractures with concomitant sternal fractures. Generally, long-segmental constructs seem to be the safer treatment strategy considering the relative high penetration rate of pedicle screws in this region. Thereby, navigated insertion techniques and intraoperative 3D-imaging help to improve pedicle screw placement accuracy.

[Minimally invasive stabilization of thoracolumbar osteoporotic fractures]. / Minimal-invasive Stabilisierung bei thorakolumbalen osteoporotischen Frakturen.

BACKGROUND: Minimally invasive stabilization of thoracolumbar osteoporotic fractures (OF) in neurologically intact patients is well established. Various posterior and anterior surgical techniques are available. The OF classification and OF score are helpful for defining the indications and choice of operative technique. OBJECTIVE: This article gives an overview of the minimally invasive stabilization techniques, typical complications and outcome. MATERIAL AND METHODS: Selective literature search and description of surgical techniques and outcome. RESULTS: Vertebral body augmentation alone can be indicated in painful but stable fractures of types OF 1 and OF 2 and to some extent for type OF 3. Kyphoplasty has proven to be an effective and safe procedure with a favorable clinical outcome. Unstable fractures and kyphotic deformities (types OF 3-5) should be percutaneously stabilized from posterior. The length of the pedicle screw construct depends on the extent of instability and deformity. Bone cement augmentation of the pedicle screws is indicated in severe osteoporosis but increases the complication rate. Restoration of stability of the anterior column can be achieved through additional vertebral body augmentation or rarely by anterior stabilization. Clinical and radiological short and mid-term results of the stabilization techniques are promising; however, the more invasive the surgery, the more complications occur. CONCLUSION: Minimally invasive stabilization techniques are safe and effective. The specific indications for the individual procedures are guided by the OF classification and the individual clinical situation of the patient.

Recommendations for Diagnosis and Treatment of Odontoid Fractures in Geriatric Patients. / Empfehlungen zu Diagnostik und Behandlung von Frakturen des Dens axis bei geriatrischen Patienten.

BACKGROUND: Odontoid fractures in geriatric patients represent an entity of increasing incidence with a high rate of morbidity and mortality. The optimal diagnostic and therapeutic management is being controversially discussed in the literature. METHODS: In a consensus process and based on the current literature, the members of the working groups "Osteoporotic Fractures" and "Upper Cervical Spine" of the German Society for Orthopaedics and Trauma Surgery (DGOU) defined recommendations for the diagnostics and treatment of odontoid fractures in geriatric patients. RESULTS: For the diagnosis of odontoid fractures in symptomatic patients, computed tomography represents the gold standard, along with conventional radiographs. Magnetic resonance and dynamic imaging can be used as ancillary imaging modalities. With regard to fracture classification, the systems described by Anderson/D'Alonzo and by Eysel/Roosen have proved to be of value. A treatment algorithm was developed based on these classifications. Anderson/D'Alonzo type 1, type 3, and non-displaced type 2 fractures usually can be treated non-operatively. However, a close clinical and radiological follow-up is essential. In Anderson/D'Alonzo type 2 fractures, operative treatment is associated with better fracture healing. Displaced type 2 and type 3 fractures should be stabilized operatively. Type 2 fractures with suitable fracture patterns (Eysel/Roosen 2A/B) can be stabilized anteriorly. Posterior C I/II-stabilization procedures are well established and suitable for all fracture patterns.

[Hounsfield units as a measure of bone density-applications in spine surgery]. / "Hounsfield units" als Maß für die Knochendichte ­ Anwendungsmöglichkeiten in der Wirbelsäulenchirurgie.

Despite today's good diagnostic and therapeutic options for osteoporosis, the number of unidentified cases is very high and therapy is therefore usually inadequate. Frequently, the diagnosis of osteoporosis is made only after the occurrence of a fracture. The reason for this, apart from the costs incurred as well as the additional radiation exposure of the diagnostics, is certainly the limited availability of dual energy X­ray absorptiometry (DEXA) as well as quantitative computed tomography (q-CT). In search of an alternative technique, Hounsfield units (HU) of the clinical CT examination proved to be ground-breaking: the results of previous investigations demonstrated a reliable correlation between the T values of the DEXA measurement and the HU of the same vertebral body. Due to the widespread use of clinical CT scans of the thorax and the abdomen for a variety of indications, it is expected that the number of unidentified cases of osteoporosis can be significantly reduced-without additional costs and radiation exposure associated with osteoporosis screening. In addition to osteoporosis diagnostics, the calculated HU may also provide better preoperative planning as well as predicting the further course of the disease. Thus, the risk for vertebral body fractures, screw loosening and cage sintering after ventral fusion operations can be sufficiently predicted. In this way, preoperative modifications to the surgical procedure can be made to reduce the risk of implant failure.

Recommendations for the Diagnostic Testing and Therapy of Atlas Fractures. / Empfehlungen zur Diagnostik und Therapie oberer Halswirbelsäulenverletzungen: Atlasfrakturen.

In a consensus process with four sessions in 2017, the working group on "the upper cervical spine" of the German Society for Orthopaedic and Trauma Surgery (DGOU) formulated "Therapeutic Recommendations for the Diagnosis and Treatment of Fractures to the Upper Cervical Spine", incorporating their own experience and current literature. The following article describes the recommendations for the atlas vertebra. About 10% of all cervical spine injuries include the axis vertebra. The diagnostic process primarily aims to detect the injury and to determine joint incongruency and integrity of the atlas ring. For classification purposes, the Gehweiler classification and the Dickman classification are suitable. The Canadian c-spine rule is recommended for clinical screening for c-spine injuries. CT is the preferred imaging modality; MRI is needed to determine the integrity of the Lig. transversum atlantis in complete atlas ring fractures. Conservative treatment is appropriate in very many atlas fractures. Surgical treatment is recommended in existing or potential joint incongruity or instability, which are frequently seen in Gehweiler IIIB or Gehweiler IV fractures. Posterior atlanto-axial stabilisation and fusion using transarticular screws or an internal fixator are regarded as a gold standard in the majority of surgical cases. Especially in young patients, the possibility of isolated atlas osteosynthesis should be checked. A possible option for Gehweiler IV fractures is halo-fixation with mild distraction for ligamentotaxis. Secondary dislocation should be checked for frequently. Involvement of the occipito-atlantal joint complex requires stabilisation of the occiput as well.

Hounsfield units as predictor for cage subsidence and loss of reduction: following posterior-anterior stabilization in thoracolumbar spine fractures.

STUDY DESIGN: A retrospective, longitudinal cohort study. OBJECTIVE: The purpose of this study was to examine whether Hounsfield units (HUs), as an alternative bone mineral density measurement to dual-energy X-ray absorptiometry and quantitative computed tomography, which lead to additional radiation exposure for patients, has an effect on the maintenance of reduction in bisegmental Cobb angle (CA) and cage subsidence in patients who receive bisegmental spine stabilization after traumatic thoracolumbar spine fractures. METHODS: A total of 81 patients with a mean follow-up of 12 months were analyzed. CAs and cage subsidence were measured intraoperatively and at follow-up. HU was measured, and patients were subsequently assigned based on HU to three HU subgroups (group 1: HU < 110 [poor bone quality (BQ)]; group 2: HU 180-110 [diminished BQ]; group 3: HU > 180 [good BQ]). RESULTS: Following anterior stabilization, loss of reduction and cage subsidence differed between patients with poor and diminished BQ but not significantly, and both groups showed significantly more loss of reduction and cage subsidence than patients with good BQ. CONCLUSION: BQ, estimated with HU, had significant effects on cage subsidence and loss of reduction. We recommend measuring HU before surgery and applying additional treatment strategies, such as polymethylmethacrylate augmentation of endplates or anterior plates, for patients with HU < 180. These slides can be retrieved under Electronic Supplementary Material.

Recommendations for Diagnosis and Treatment of Fractures of the Ring of Axis. / Empfehlungen zur Diagnostik und Therapie oberer Halswirbelsäulenverletzungen: Axisringfrakturen.

In a consensus process with four sessions in 2017, the working group "upper cervical spine" of the German Society for Orthopaedics and Trauma Surgery (DGOU) formulated "Therapeutic Recommendations for the Diagnosis and Treatment of Upper Cervical Fractures", taking their own experience and the current literature into consideration. The following article describes the recommendations for axis ring fractures (traumatic spondylolysis C2). About 19 to 49% of all cervical spine injuries include the axis vertebra. Traumatic spondylolysis of C2 may include potential discoligamentous instability C2/3. The primary aim of the diagnostic process is to detect the injury and to determine potential disco-ligamentous instability C2/3. For classification purposes, the Josten classification or the modified Effendi classification may be used. The Canadian C-spine rule is recommended for clinical screening for C-spine injuries. CT is the preferred imaging modality and an MRI is needed to determine the integrity of the discoligamentous complex C2/3. Conservative treatment is appropriate in case of stable fractures with intact C2/3 motion segment (Josten type 2 and 2). Patients should be closely monitored, in order to detect secondary dislocation as early as possible. Surgical treatment is recommended in cases of primary severe fracture dislocation or discoligamentous instability C2/3 (Josten 3 and 4) and/or secondary fracture dislocation. Anterior cervical decompression and fusion (ACDF) C2/3 is the treatment of choice. However, in case of facet joint luxation C2/3 with looked facet (Josten 4), a primary posterior approach may be necessary.