Partial weight-bearing following ankle fracture: what's the actual load in early recovery?

PURPOSE: This study investigates the learning efficacy for partial weight load before discharge as well as the impact of biofeedback during the learning process. METHODS: We monitored weight-bearing in 57 patients who had surgery for ankle fractures. Continuous measurements without and with biofeedback were performed in the early postoperative stage in order to, first, assess how well these patients could apply what they have learned before being discharged, and second, to examine the influence of biofeedback. RESULTS: Using conventional teaching methods, only about one-third of patients (36.8% on the ground and 29.2% on the stairs) were able to maintain a satisfactory load. One-fourth of the patients did not place any weight on their leg, which was shown to be due to excessive pain at the time of the measurement (p < 0.05). A further one-fourth loaded inadequately low, while the remainder loaded excessively. Patients benefited significantly from the activation of audio-visual biofeedback in real time. As a result, loads in a target zone between 15 and 30 kg could be significantly increased (p < 0.05). CONCLUSION: We conclude that the majority of ankle fracture patients were unable to learn partial weight bearing in the early postoperative stage using traditional techniques. Additionally, each patient's ability to carry out a given loading varied. Using an audio-visual real-time biofeedback modality led to significantly improved performance. These findings support the proposed utility of audiovisual feedback in early rehabilitation. With the use of outpatient real-time biofeedback systems, therapists will be able to respond specifically to the needs of each individual patient. TRIAL REGISTRATION: Trial registration: DRKS00031136, Registered 01.02.2023 - Retrospectively registered, https://www.drks.de/DRKS00031136.

Paediatric spine injuries in the thoracic and lumbar spine-results of the German multicentre CHILDSPINE study.

BACKGROUND: Paediatric thoracolumbar spine injuries are rare, and meaningful epidemiological data are lacking. OBJECTIVES: The aim of this study was to provide epidemiological data for paediatric patients with thoracolumbar spinal trauma in Germany with a view to enhancing future decision-making in relation to the diagnostics and treatment of these patients. MATERIALS AND METHODS: A retrospective multicentre study includes patients up to 16 years of age who were suffering from thoracolumbar spine injuries who had been treated in six German spine centres between 01/2010 and 12/2016. The clinical database was analysed for patient-specific data, trauma mechanisms, level of injury, and any accompanying injuries. Diagnostic imaging and subsequent treatment were investigated. Patients were divided into three age groups for further evaluation: age group I (0-6 years), age group II (7-9 years) and age group III (10-16 years). RESULTS: A total of 153 children with 345 thoracolumbar spine injuries met the inclusion criteria. The mean age at the time of hospitalization due to the injury was 12.9 (± 3.1) years. Boys were likelier to be affected (1:1.3). In all age groups, falls and traffic accidents were the most common causes of thoracolumbar spine injuries. A total of 95 patients (62.1%) were treated conservatively, while 58 (37.9%) of the children underwent surgical treatment. Minimally invasive procedures were the most chosen procedures. Older children and adolescents were likelier to suffer from higher-grade injuries according to the AOSpine classification. The thoracolumbar junction (T11 to L2) was the most affected level along the thoracolumbar spine (n = 90). Neurological deficits were rarely seen in all age groups. Besides extremity injuries (n = 52, 30.2%), head injuries represented the most common accompanying injuries (n = 53, 30.8%). Regarding spinal injuries, most of the patients showed no evidence of complications during their hospital stay (96.7%). CONCLUSIONS: The thoracolumbar junction was more frequently affected in older children and adolescents. The majority of thoracolumbar spinal column injuries were treated conservatively. Nevertheless, 37.9% of hospitalized children had to be treated surgically, and there was an acceptable complication rate for the surgeries that were performed.

Continuous real-time biofeedback in orthosis improves partial weight bearing on stairs.

INTRODUCTION: Climbing up and down stairs with crutches is a particular challenge. The current study evaluates a commercially available insole orthosis device for weighing an affected limb and for biofeedback training of gait. This study was done on healthy, asymptomatic individuals before applying to the intended postoperative patient. The outcomes should demonstrate whether a continuous real-time biofeedback (BF) system is more effective on stairs than the current protocol involving a bathroom scale. MATERIALS AND METHODS: 59 healthy test subjects received both crutches and an orthosis and learned to apply a 3-point gait with a partial load of 20 kg using a bathroom scale. Thereafter, the participants were asked to complete an up-and-down course, first without (control group) and then with (test group) an audio-visual real-time biofeedback (BF). Compliance was evaluated using an insole pressure measurement system. RESULTS: Using the conventional therapy technique, 36.6% of the steps up and 39.1% of the steps down in the control group were loaded with < 20 kg. By activating continuous biofeedback, steps with < 20 kg could be increased significantly to 61.1% upstairs (p < 0.001) and 66.1% downstairs (p < 0.001). All subgroups profited from the BF system, independent of age, gender, side relieved, dominant or non-dominant side. CONCLUSIONS: Traditional training without biofeedback led to poor performance for partial weight bearing on stairs, even among young and healthy individuals. However, continuous real-time biofeedback clearly improved compliance, indicating its potential to enhance training and support future research in patient populations.

Can elderly individuals perform partial weight bearing on their lower limbs? A prospective cohort study using ambulatory real-time biofeedback.

BACKGROUND: Partial weight bearing in an orthosis and with forearm crutches is a widespread and well-accepted therapeutic principle after an injury of the lower extremity during early rehabilitation. Complying may be challenging to do under these circumstances, especially for elderly people. This study compares the spatiotemporal parameters and peak loads performed by a group of older participants before and after activating real-time biofeedback (BF) to determine whether they benefit from a biofeedback. METHODS: Twenty-four healthy subjects between 61 and 80 years learned how to walk using forearm crutches in a lower leg orthosis while performing a weight of 20 kg using a bathroom scale with the aim of loading in a zone between 15 and 30 kg. After that, they completed a course that was on level ground (50 m) and another course on stairs (11 steps). They did a walk without BF first, and then with BF. Each step was given a maximum load, which was determined and statistically checked. In addition, spatiotemporal parameters were collected. RESULTS: The classical teaching method with a bathroom scale was ineffective. Only 32.3% of the loads could be adequately carried by a person on level ground in the 15-30 kg target zone. On the stairs, it was 48.2% and 34.3%, respectively. Thus, on level ground, 52.7% of loads exceeded 30 kg. Downstairs it was 46.4%, and upstairs it was 41.6%. Subjects clearly benefit from activated biofeedback. Biofeedback significantly reduced missteps > 30 kg in every course. The loads decreased significantly to 25.0% on level ground, to 23.0% upstairs, and to 24.4% downstairs. At the same time, speed and stride length decreased per course while total time increased. CONCLUSION: Partial weight bearing is more complex and difficult for the elderly. These study results may help better understand 3-point gait in older adults in an outpatient setting. When partial weight bearing is recommended, special follow-up attention must be given for this group. Age-based therapy strategies can be developed and monitored with the assistance of ambulatory biofeedback devices. Trial registration Retrospectively registered, https://www.drks.de/DRKS00031136 .

Pediatric cervical spine injuries-results of the German multicenter CHILDSPINE study.

OBJECTIVES: The aim of this study was to provide epidemiological data of pediatric patients suffering from cervical spinal trauma in Germany, in order to integrate these data in future decision-making processes concerning diagnosis and therapy. MATERIALS AND METHODS: Retrospective multicenter study includes all patients up to 16 years suffering from cervical spine injuries who were treated in six German spine centers between 01/2010 and 12/2016. The clinical databases were screened for specific trauma mechanism, level of injury as well as accompanying injuries. Diagnostic imaging and the chosen therapy were analyzed. Patients were divided into three age groups for further evaluation: age group I (0-6 years), age group II (7-9 years), age group III (10-16 years). RESULTS: A total of 214 children with 265 cervical spine injuries were included during the mentioned period. The mean age at the time of injury was 11.9 (± 3.9) years. In age group I, 24 (11.2%) patients were included, age group II consisted of 22 patients (10.3%), and 168 patients belonged to age group III (78.5%). Girls and boys were equally affected. In all age groups, falls and traffic accidents were the most common causes of cervical spine injuries. A total of 180 patients (84.1%) were treated conservatively, while 34 (15.9%) children underwent surgery. Distorsion/whiplash injury was the most common entity (n = 165; 68.2%). Children aged 0-9 years had significantly (p < 0.001) more frequent injuries of the upper cervical spine (C0-C2) compared to older age groups. Patients of age group III were more likely to suffer from injuries in subaxial localizations. Neurological deficits were rarely seen in all age groups. Head injuries did represent the most common accompanying injuries (39.8%, n = 92). CONCLUSIONS: The upper cervical spine was more frequently affected in young children. Older children more often suffered from subaxial pathologies. The majority of cervical spinal column injuries were treated conservatively. Nevertheless, 15% of the hospitalized children had to be treated surgically.

Protective and Risk Factors for Humerus Head Necrosis After Proximal Humerus Fracture Treated with Internal Locking Plate.

BACKGROUND: Proximal humerus fractures (PHF) are common and lead to post-traumatic humerus head necrosis (HHN) in 3-35% after ORIF with an internal locking plate. Few studies focus on this condition and risk factors remain a discussion topic. Hertel's criteria for initial head ischemia right after fracture (fracture complexity, medial hinge displacement and short metaphyseal head extension) have recently been correlated to HHN, but there is still a clear lack of evidence on the topic. Due to its anatomical similarities to the proximal femur, some authors argue that PHF may as well benefit from early surgery to avoid head necrosis. METHODS: In this 10-year retrospective study, we assessed 305 patients from a single center. All cases were treated with a PHILOS plate through a deltopectoral approach. The mean follow-up time was 467 days. The primary endpoint was HHN. RESULTS: HHN was diagnosed in 12 patients (4%), 10 of which were diagnosed within the first year and one case 4 years after surgery. A positive correlation (p < 0.04) was found between HHN and fracture type (both in AO and Neer's classification), initial neck-shaft-angle (NSA) and metaphyseal head extension (MHE). Medial hinge displacement (MHD) occurred in all HHN cases. Achieving perfect reduction (< 2 mm dislocation) was relevant to avoiding HHN (p = 0.035). Although HHN developed in 32% of the high risk cases (four-part fractures with a short MHE), it was completely avoided (0%) when perfect reduction was achieved. Time until surgery after admission was neither a protective nor a risk factor for HHN. CONCLUSION: We conclude that fracture complexity (four-part and C-fractures) as well as disruption of the medial hinge with a metaphyseal head extension smaller than 8 mm are relevant risk factors for humerus head necrosis. A combination of these criteria generated an high risk pattern with a 32% rate of HHN. Though often difficult to achieve, perfect reduction was a clear protective factor and reduced HHN to 0%. Perfect reduction may be key to inosculation and, therefore, salvage of the humerus head, especially in high risk cases. Surgery timing did not correlate with HHN. LEVEL OF EVIDENCE: Level 3, retrospective cohort study.

Shoulder function after helical long PHILOS plate.

BACKGROUND: In order to minimize the risk of damaging the radial nerve while using a long PHILOS plate for proximal humerus fractures, recent studies have proposed twisting the plate in a helical form. This implies a modified surgical approach being yet unclear whether it leads to different middle to long-term shoulder function. This study compares the one-year shoulder functional outcomes of both techniques (helical vs. control). METHODS: In this retrospective comparative study, we analyzed 30 patients that fit the inclusion criteria, being 14 treated with a helical plate and 16 with a conventional straight long PHILOS plate. The primary endpoint was the normalized constant score after a minimum follow up of one year. RESULTS: Both groups had a good one-year shoulder function, and no significant difference between the normalized constant scores was seen. There was no significant difference in the surgical complications as well. CONCLUSION: Opting for a helical long PHILOS plate in order to avoid radial nerve damage provided a safe treatment with similarly good one-year shoulder function compared to straight PHILOS plates. LEVEL OF EVIDENCE: Level 3, Retrospective Cohort Study.

Comparing iatrogenic radial nerve lesions in humeral shaft fractures treated with helical or straight PHILOS plates: a 10-year retrospective cohort study of 62 cases.

BACKGROUND: Humerus shaft fractures are common and often treated surgically with a proximal humerus internal locking system like the long PHILOS® plate. Due to its close anatomical proximity to the humerus, the radial nerve is particularly susceptible to traumatic and iatrogenic damage. The iatrogenic radial nerve damage associated with internal locking systems is described in about 7% of the cases. In order to avoid this lesion, helical plates have been suggested since 1999. This technique continues to not being used as standard as there is still a clear lack of evidence. This study aimed to understand if twisting a long PHILOS plate can reduce the rate of iatrogenic radial nerve damage in humerus shaft fractures. METHODS: In this 10-year retrospective comparative study, patients with primary traumatic proximal humerus shaft fracture treated with a straight or twisted helical PHILOS® plate were analyzed and compared. Among the 62 patients meeting the inclusion criteria between 2008 and 2018, 33 received a conventional straight plate, while 29 were treated with a helical plate. The primary endpoint was iatrogenic radial nerve damage immediately after surgery with a follow-up of at least 3 months. RESULTS: No case of radial nerve damage was reported in the helical group. In the control group, iatrogenic radial nerve damage occurred in two cases (6%), which was not statistically significant when comparing both groups (p = 0.18). CONCLUSION: Manually twisting long PHILOS® plates is a safe procedure to avoid radial nerve lesion in humerus shaft fractures. Even though the group size did not allow a statistically relevant difference, we underline that only the helical group showed no iatrogenic radial lesion. This technique deserves further attention. LEVEL OF EVIDENCE: Level 3, retrospective cohort study.

[Diagnostics and treatment of cervical spine trauma in pediatric patients : Recommendations from the Pediatric Spinal Trauma Group]. / Diagnostik und Therapie von Verletzungen der Halswirbelsäule im Kindesalter : Empfehlungen der AG Wirbelsäulentrauma im Kindesalter.

BACKGROUND: Severe cervical spine injuries in children under the age of 17 years are rare. Recommendations or even guidelines for the diagnostics and treatment of such injuries in children are currently not available. OBJECTIVE: The aim of the study was to formulate recommendations for diagnostics and treatment of injuries of the cervical spine in pediatric patients. MATERIAL AND METHODS: First, a search of primary and secondary literature on the topic complex of diagnostics and treatment of cervical spine injuries in children was carried out. An appropriate internal literature database was defined and maintained. Second, within the framework of 9 meetings from April 2017 to December 2019 the members of the Pediatric Spinal Trauma Group of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU) systematically formulated recommendations for the diagnostics and treatment of injuries of the cervical spine in pediatric patients by a consensus process. RESULTS: Recommendation for the diagnostics and treatment for injuries of the cervical spine could be formulated for three age groups (age group I: 0-6 years; age group II: 7-9 years; age group III: 10-16 years). The diagnostic and therapeutic principles known from adult patients suffering from injuries to the cervical spine cannot be easily transferred to pediatric patients. CONCLUSION: Injuries to the pediatric spine are rare and should be treated in specialized spine centers. Pediatric patients with a stable cardiopulmonary status should undergo magnetic resonance imaging (MRI) if a spinal trauma is suspected. Classification systems and therapeutic recommendations for injuries to the cervical spine known from adult patients could also be used for adolescent patients. This is not possible for children under the age of 10 years. Only few classification systems exist for this age group. Basic principles of the treatment of spinal trauma in children is the restoration of spinal stability and correct anatomical relationships as well as the protection of all neural structures.

[Diagnostics and treatment of thoracic and lumbar spine trauma in pediatric patients : Recommendations from the Pediatric Spinal Trauma Group]. / Diagnostik und Therapie von Verletzungen der Brust- und Lendenwirbelsäule im Kindesalter : Empfehlungen der AG Wirbelsäulentrauma im Kindesalter.

BACKGROUND: Spinal injuries in pediatric patients are overall very rare. Current reference studies including large patient numbers that enable the formulation of evidence-based recommendations on diagnostics and treatment of these injuries do not exist. OBJECTIVE: The aim of the current study was to formulate recommendations on the diagnostics and treatment for injuries of the thoracic and lumbar spine in pediatric patients. MATERIAL AND METHODS: Firstly, a search for primary and secondary literature on the topic of diagnostics and treatment of spinal injuries in children was carried out. From this, a literature database was established and maintained. Secondly, within the framework of 9 meetings in the time period from April 2017 to December 2019 the members of the Pediatric Spinal Trauma Group of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU) documented recommendations on diagnostics and treatment of injuries of the thoracic and lumbar spine in pediatric patients by a consensus process. RESULTS: Recommendations on the diagnostics and treatment of injuries of the thoracic and lumbar spine could be given for 3 age groups (age group I: 0-6 years; age group II: 7-9 years; age group III: 10-16 years). Diagnostic and therapeutic principles known from adult patients suffering from injuries to the thoracic or lumbar spine cannot easily be transferred to pediatric patients. CONCLUSION: Spinal injuries in childhood are rare and should be treated in specialized spine centers. Pediatric patients with a stable cardiopulmonary status should undergo magnetic resonance imaging (MRI) if a spinal trauma is suspected. The basic principles of the treatment of spinal trauma in children is the restoration of spinal stability and correct anatomical parameters as well as the protection of all neural structures. The potential for correction and regeneration of the individual spinal sections depending on the age of the patient must be considered for deciding between operative vs. conservative treatment. Whenever operative treatment is needed, it should be performed by minimally invasive techniques as a sole instrumentation without spondylodesis. An early removal of the screw-rod-system should be performed.

[Pediatric spine trauma-Results of a German national multicenter study including 367 patients]. / Wirbelsäulenverletzungen im Kindesalter ­ Ergebnisse einer nationalen Multizenterstudie mit 367 Patienten.

BACKGROUND: In general, pediatric spinal injuries are rare. No reliable data on the epidemiology of spinal injuries in pediatric patients in Germany are available. Especially in pediatric patients, for whom the medical history, clinical examination and the performance of imaging diagnostics are difficult to obtain, all available information on a spinal injury must be taken into account. OBJECTIVE: The aim of this study was to provide epidemiological data for pediatric patients with spinal trauma in Germany in order to enhance future decision-making for the diagnostics and treatment of these patients. MATERIAL AND METHODS: Within the framework of a national multicenter study, data were retrospectively obtained from 6 German spine centers for 7 years between January 2010 and December 2016. In addition to the demographic data, the clinical databases were screened for specific trauma mechanisms, level of injury as well as accompanying injuries. Furthermore, diagnostic imaging and the treatment selected were also analyzed. RESULTS: A total of 367 children (female: male = 1:1.2) with a total of 610 spinal injuries were included in this study. The mean age was 12 years (±3.5 years). The most frequent trauma mechanisms were falls from <3 m and traffic accidents. The imaging diagnostics were only rarely carried out with the child under anesthesia. Younger children (0-9 years old) suffered more injuries to the cervical spine, whereas injuries to the thoracic and lumbar spine were more frequently found in older children (>10 years old). The children frequently showed accompanying injuries to the head and the extremities. Accompanying spinal injuries mostly occurred in adjacent regions and only rarely in other regions. Around 75% of the children were treated conservatively. CONCLUSION: The results were different from the knowledge obtained from adult patients with spinal trauma and describe the special circumstances for pediatric patients with spinal trauma. Despite certain limitations these facts may help to enhance future decision-making for the diagnostics and treatment of these patients.

Treatment of Fractures of the Thoracolumbar Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

STUDY DESIGN: consensus paper with systematic literature review. OBJECTIVE: The aim of this study was to establish recommendations for treatment of thoracolumbar spine fractures based on systematic review of current literature and consensus of several spine surgery experts. METHODS: The project was initiated in September 2008 and published in Germany in 2011. It was redone in 2017 based on systematic literature review, including new AOSpine classification. Members of the expert group were recruited from all over Germany working in hospitals of all levels of care. In total, the consensus process included 9 meetings and 20 hours of video conferences. RESULTS: As regards existing studies with highest level of evidence, a clear recommendation regarding treatment (operative vs conservative) or regarding type of surgery (posterior vs anterior vs combined anterior-posterior) cannot be given. Treatment has to be indicated individually based on clinical presentation, general condition of the patient, and radiological parameters. The following specific parameters have to be regarded and are proposed as morphological modifiers in addition to AOSpine classification: sagittal and coronal alignment of spine, degree of vertebral body destruction, stenosis of spinal canal, and intervertebral disc lesion. Meanwhile, the recommendations are used as standard algorithm in many German spine clinics and trauma centers. CONCLUSION: Clinical presentation and general condition of the patient are basic requirements for decision making. Additionally, treatment recommendations offer the physician a standardized, reproducible, and in Germany commonly accepted algorithm based on AOSpine classification and 4 morphological modifiers.

Spine Fractures in Ankylosing Diseases: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

STUDY DESIGN: Review of literature and case series. OBJECTIVES: Update and review of current treatment concepts for spine fractures in patients with ankylosing spinal disorders. METHODS: Case presentation and description of a diagnostic and therapeutic algorithm for unstable spinal injuries with an underlying ankylosing spinal disorder (ASD) of the cervical and thoracolumbar spine. RESULTS: Nondisplaced fractures can be missed easily using conventional X-rays. Thus, computed tomography (CT) scans are recommended for all trauma patients with ASD. In doubt or presence of any neurologic involvement additional magnetic resonance imaging (MRI) scans should be obtained. Spine precautions should be maintained all times and until definitive treatment (<24 h). Nonoperative fracture treatment is not recommended given the mechanical instability of the most commonly seen fracture patterns (AOSpine B- and C-type, M2) in patients with ASD and inherent high risk of secondary neurologic deterioration. For patients with ankylosing spondylitis (AS) or diffuse idiopathic hyperostosis (DISH) sustaining cervical spine fractures, a combined anterior-posterior instrumentation for fracture fixation is recommended. Closed reduction and patient positioning can be challenging in presence of preexisting kyphotic deformities. In the thoracolumbar (TL) spine, a posterior instrumentation extending 2 to 3 levels above and below the fracture level is recommended to maintain adequate reduction and stability until fracture healing. Minimally invasive percutaneous pedicle screws and cement augmentation can help to minimize the surgical trauma and strengthen the construct stability in patients with diminished minor bone quality (osteopenia, osteoporosis). CONCLUSIONS: Current concepts, treatment options, and recommendations of the German Orthopedic Trauma Society-Spine Section for spinal fractures in the ankylosed spine have been outlined.

Combined posterior-anterior stabilisation of thoracolumbar injuries utilising a vertebral body replacing implant.

The authors report on a prospectively followed series of 35 patients with injuries of the thoracolumbar spine from T7 to L3. The radiological course after combined posterior-anterior surgery with anterior column reconstruction with a distractible vertebral body replacing implant demonstrated a stable reconstruction technique with almost no re-kyphosing. In 18/18 patients with CT follow-up intervertebral fusion was observed as bony bridging lateral to the VBR implant. The functional/clinical outcome of the patients was analysed with a set of eight validated outcome scales. After an average follow-up period of 2(1/2) years encouraging results were noticed. The neurological improvement rate (> or =1 Frankel/ASIA grade) was 8/12 patients (67%) with a complete recovery in 6 cases. 17/29 patients returned to former occupation; 20/29 patients returned to former leisure activities; 24/28 patients rated their general outcome as "unlimited and pain free" or "occasionally and/or mild complaints" with a VAS score of >80 (scale 0-100). The psychometric questionnaires revealed good results with strong correlation comparing the different scoring systems statistically: mean McGill Pain Questionnaire 12.5 (0-40); mean Oswestry Disability Index 20% (0-51). 13/29 patients scored <4 in the Roland and Morris Disability Questionnaire. The German back pain questionnaire (Funktionsfragebogen Hannover Rücken) showed a mean "functional capacity" of 75%, corresponding with moderate restriction. We concluded the presented method as highly effective to completely reduce and maintain an anatomic spinal alignment. The outcome tended to be better in comparison with non-operatively treated patients as well as with norm populations with low back pain.

A new distractable implant for vertebral body replacement: biomechanical testing of four implants for the thoracolumbar spine.

INTRODUCTION: Expandable titanium implants for vertebral body replacement in the thoracolumbar spine have been well established in the reconstruction of the anterior spinal column. Load transfer at the bone-implant interface remains a point of concern. The purpose of the study was to compare the performance in axial load transfer from the implant to the vertebral body in four different implants, all of them in clinical use to date. MATERIALS AND METHODS: We tested a second generation implant (Synex II) in comparison to three different expandable titanium cages: Synex I, Obelisc and X-Tenz. Twenty-four intact fresh frozen human lumbar vertebrae (L1-L4) were distributed into four identical groups according to bone mineral density (BMD). The BMD was determined by quantitative computed tomography (qCT). Specimens were loaded in craniocaudal direction with a material testing machine (Mini Bionix II) at a constant speed of 5 mm/min. Load displacement curves were continuously recorded for each specimen until failure (diminishment of compressive force (F) and/or obvious implant migration through the vertebral body end plate). One-way analysis of variance (ANOVA) and post-hoc tests (Bonferroni) were applied to detect differences at 1, 2, 3, and 4 mm displacement (F (1-4 mm)) between implant groups. RESULT: No significant differences were observed with regard to maximum compression force (F (max)) and displacement (d (max)) until failure: Synex II (1,782.3 N/4.67 mm); Synex I (1,645.3 N/4.72 mm); Obelisc (1,314.0 N/4.24 mm); X-Tenz (1470.3 N/6.92 mm). However, the mean compression force at 1-4 mm displacement (F (1-4 mm): 300-1,600 N) was highest for Synex II. The difference at 2 mm displacement was significant (p = 0.028) between Synex II (F (2 mm) = 879 N) and X-Tenz (F (2 mm) = 339 N). CONCLUSION: The modified end plate design of Synex II was found to perform comparably at least with regard to the compressive performance at the implant-bone interface. The risk of the new implant for collapse into the vertebral body might be reduced when compared to the competitors.

Angular stable anterior plating following thoracolumbar corpectomy reveals superior segmental stability compared to conventional polyaxial plate fixation.

STUDY DESIGN: Biomechanical in vitro testing of primary and secondary stability in 12 human thoracolumbar spinal specimens using a spine simulator. OBJECTIVE: In a corpectomy model anterior plate systems were investigated for their ability to restore spinal stability particularly focusing on the influence of angular stability, bone mineral density (BMD) and failure mode. SUMMARY OF BACKGROUND DATA: The concept of isolated anterior column reconstruction following thoracolumbar fractures using newly developed minimally invasive spine surgical techniques has attracted major clinical interest. In analogy to angular stable plate systems in long bone fixation the application of locking plates to the spine is aimed to limit loss of reduction and to improve stability. METHODS: Twelve human spinal specimens (Th11-L3) were tested in a 6-degree-of-freedom spine simulator under pure moments of 7.5 Nm to investigate primary and secondary stiffness of 2 different anterior reconstruction options: (1) Synex II cage and MACS TL polyaxial anterior plating system, (2) Synex II cage and ArcoFix angular stable anterior plating system. An increasing 4-step cyclic loading model was included. RESULTS: The angular stable plate system showed superior stability compared to the nonangular system in axial rotation and lateral bending. Flexion/extension loading demonstrated no difference between the systems in range of motion. A positive correlation between BMD and the number of load cycles until failure for the nonangular stable system (R2 = 0.90) was found. Different failure modes were investigated for the plating systems. The MACS system showed loosening at the connection between screw and plate inducing tilting under flexural load and final failure. The ArcoFix system revealed increased stability under cyclic loading and failed by parallel sintering to the endplate. CONCLUSION: Anterior angular stable fixation showed higher primary and secondary stability following thoracolumbar corpectomy. In specimens with lower BMD the use of angular stable systems substantially increased stability. Angular stable systems, however, differ in the way of construct failure.

Higher risk of adjacent segment degeneration after floating fusions: long-term outcome after low lumbar spine fusions.

STUDY DESIGN: We report the long-term outcome after mono-segmental and bisegmental fusions at the lumbar L4-S1 region of the spine. OBJECTIVE: Long-term clinical and radiologic outcome measures were used to determine a lumbar fusion's contribution to degenerative changes in adjacent motion segments (ASD). SUMMARY OF BACKGROUND DATA: The role of low lumbar spinal fusions and their long-term contribution to accelerated degenerative changes in the adjacent motion segments continues to be a subject of controversy. PATIENTS AND METHODS: We followed-up 102 patients with an average age of 54 (22 to 78) years and a follow-up time of 14 (3 to 22) years. RESULTS: Overall results in patients were good, the Oswestry-Disability Index (ODI) showed an average of 26% (0% to 70%) at follow-up, the Visual Analog Scale rose from 2.7 (postoperative) and 2.9 (12 wk follow-up) to 3.6 (latest follow-up) points, respectively. Patient satisfaction with their health-related situation at follow-up was 69% (15% to 100%). Patients who underwent fusions of the segment L5/S1 showed a significant (P<0.05) lower risk for ASD than patients with fusions L4/5 (20% vs. 46%). Compared with L4/5 fusions, bisegmental L4-S1 fusions showed a similar trend (P=0.06) with a lower risk for ASD (24%). Objective and subjective clinical results showed no differences between these groups. Patients suffering from ASD showed significant (P<0.05) reduced sacral inclination and lumbar lordosis angles and also significant (P<0.05) higher ODI values compared with non-ASD patients. CONCLUSIONS: We conclude that floating fusions of single low lumbar segments are more likely to result in ASD and are negatively influenced by sagittal plane abnormalities.

Anterior vertebral body replacement with a titanium implant of adjustable height: a prospective clinical study.

In the operative treatment of spinal injuries, the reconstruction of the anterior column of the thoracolumbar spine is still controversial. We conducted a prospective clinical study to investigate the clinical and radiological outcome of 50 patients treated with a vertebral body replacement of adjustable height (Synex). Fifty consecutive patients were evaluated during in-patient treatment and at 12 and 20 months post-operatively in clinical notes and radiographs. 38/50 patients were operated for traumatic fractures. Out of 50 patients 45 attended the follow-up clinic 1 year post-operatively and 39 of these patients were examined after 20 months. Twenty-five patients returned to pre-injury activities within 1 year. This number increased to 29/39 patients at 20 months. Seventy-three percent of the patients returned to their job. After 1 year 25/45 patients complained of little or no back pain and 6 months later six patients were limited in their back function. At 1 year only three patients complained of surgical site pain which was improved at their final follow-up at 20 months. Individual satisfaction was determined using a score on a visual analog scale containing 19 questions on back pain, and functional limitation of the spine that has to be filled in by the patients at three different points of time. The score decreased from 87/100 pre-operatively to 65/100 at 1 year follow-up (P<0.001). The average permanent correction of the injured vertebra was 16.8 degrees (88%) including 2.3 degrees (12%) loss of correction at 12 months after operation. Bony integration was obtained in 83%. Early and intermediate outcome with the Synex vertebral replacement device for reconstruction of the anterior column appears promising. The loss of correction or reduction was only minimal. On the basis of our results we recommend the Synex implant as an alternative for the fixation and stabilisation of thoracolumbar fractures. However, long-term results and a clinically random control study are still required.

Internet based multicenter study for thoracolumbar injuries: a new concept and preliminary results.

This article reports about the internet based, second multicenter study (MCS II) of the spine study group (AG WS) of the German trauma association (DGU). It represents a continuation of the first study conducted between the years 1994 and 1996 (MCS I). For the purpose of one common, centralised data capture methodology, a newly developed internet-based data collection system ( http://www.memdoc.org ) of the Institute for Evaluative Research in Orthopaedic Surgery of the University of Bern was used. The aim of this first publication on the MCS II was to describe in detail the new method of data collection and the structure of the developed data base system, via internet. The goal of the study was the assessment of the current state of treatment for fresh traumatic injuries of the thoracolumbar spine in the German speaking part of Europe. For that reason, we intended to collect large number of cases and representative, valid information about the radiographic, clinical and subjective treatment outcomes. Thanks to the new study design of MCS II, not only the common surgical treatment concepts, but also the new and constantly broadening spectrum of spine surgery, i.e. vertebro-/kyphoplasty, computer assisted surgery and navigation, minimal-invasive, and endoscopic techniques, documented and evaluated. We present a first statistical overview and preliminary analysis of 18 centers from Germany and Austria that participated in MCS II. A real time data capture at source was made possible by the constant availability of the data collection system via internet access. Following the principle of an application service provider, software, questionnaires and validation routines are located on a central server, which is accessed from the periphery (hospitals) by means of standard Internet browsers. By that, costly and time consuming software installation and maintenance of local data repositories are avoided and, more importantly, cumbersome migration of data into one integrated database becomes obsolete. Finally, this set-up also replaces traditional systems wherein paper questionnaires were mailed to the central study office and entered by hand whereby incomplete or incorrect forms always represent a resource consuming problem and source of error. With the new study concept and the expanded inclusion criteria of MCS II 1, 251 case histories with admission and surgical data were collected. This remarkable number of interventions documented during 24 months represents an increase of 183% compared to the previously conducted MCS I. The concept and technical feasibility of the MEMdoc data collection system was proven, as the participants of the MCS II succeeded in collecting data ever published on the largest series of patients with spinal injuries treated within a 2 year period.

Influence of screw positioning in a new anterior spine fixator on implant loosening in osteoporotic vertebrae.

STUDY DESIGN: A biomechanical study was designed to assess implant cut-out of three different angular stable anterior spinal implants. Subsidence of the implant relative to the vertebral body was measured during an in vitro cyclic loading test. OBJECTIVES: The objective of the study was to evaluate two prototypes (Synthes) of a new anterior spine fixator with different screw angulations in comparison to the established MACSTL(R) Twin Screw Concept (Aesculap). The influence of factors like load-bearing cross-sectional area, screw angulation and bone mineral density upon implant stability should be investigated. SUMMARY OF BACKGROUND DATA: Epidemiologic data predict a growing demand for appropriate anterior spinal fixation devices especially in patients with inferior structural and mechanical bone properties. Although different concepts for anterior spinal instrumentation systems have been tried out, implant stability is still a problem. METHODS: Three angular stable, anterior spinal implants were tested using 24 human lumbar osteoporotic vertebrae (L1-L5; age 84 (73-92)): MASC TL system (Aesculap); prototype 1 (MP1) with 18 degrees and prototype 2 (MP2) with 40 degrees screw angulation (both Synthes). All implants consisted of two screws with different outer screw diameters: 7-mm polyaxial screw with 6.5-mm stabilization screw (MASC TL), two 5-mm locking-head screws each (MP1 and MP2). Bone mineral density (BMD) and vertebral body width of the three specimen groups were evenly distributed. The specimens were loaded in craniocaudal direction (1Hz) for 1000 cycles each at three consecutive load steps; 10-100 N, 10-200 N and 10-400 N. During cyclic loading subsidence of the implant relative to the vertebral body was measured in the unloaded condition. Cycle number at failure (defined as a subsidence of 2 mm) was determined for each specimen. A survival analysis (Cox Regression) was performed to detect differences between implant groups at a probability level of 95%. RESULTS: High correlations were found between BMD and number of cycles until failure (MP1; r = 0.905, P = 0.013; MP2: r = 0.640, P = 0.121; MACS TL: r = 0.904, P = 0.013) and between load bearing cross sectional area and number of cycles until failure (MP1: r = 0.849, P = 0.032;MP2: r = 0.692, P = 0.085; MACS TL: r = 0.902, P = 0.014). Both Prototypes survived significantly longer than the MACS TL implant (MP1: P = 0.012, MP2: P = 0.014). The survival behaviour of MP1 and MP2 was not significantly different (P = 0.354). CONCLUSIONS: Implant stability within each implant group was influenced by BMD and load bearing cross-sectional area. The angulation of the two screws did not have a significant influence on cut-out. As conclusion from this study, promising approaches for further implant development are: 1) increase of load-bearing cross-sectional area (e.g., larger outer diameter of the anchorage device), 2) screw positioning in areas of higher BMD (e.g., opposite cortex, proximity to pedicles or the endplates).