[Cement augmentation in spinal surgery]. / Zementaugmentation in der Wirbelsäulenchirurgie.

Bone cement has been used in spinal surgery for as long as 50 years. In contemporary spinal surgery, cement augmentation of fractured osteoporotic vertebrae in the form of vertebroplasty/kyphoplasty as well as cement augmentation of pedicle screws in instrumented procedures of any etiology are established as standard procedures. Both procedures are very effective, although the benefits of vertebroplasty/kyphoplasty procedures have been controversially discussed in the past. Overall, complications rarely occur. The most relevant complication is cement leakage, which is asymptomatic in the majority of cases but in the worst case might lead to neurological deficits, embolic events and even circulatory collapse. Prevention of cement leakage is therefore crucial. Risk factors for cement leakage and preventive measures are presented in a comprehensive review based on the available literature.

OF-Pelvis classification of osteoporotic sacral and pelvic ring fractures.

OBJECTIVES: Osteoporotic fractures of the pelvis (OFP) are an increasing issue in orthopedics. Current classification systems (CS) are mostly CT-based and complex and offer only moderate to substantial inter-rater reliability (interRR) and intra-rater reliability (intraRR). MRI is thus gaining importance as a complement. This study aimed to develop a simple and reliable CT- and MRI-based CS for OFP. METHODS: A structured iterative procedure was conducted to reach a consensus among German-speaking spinal and pelvic trauma experts over 5 years. As a result, the proposed OF-Pelvis CS was developed. To assess its reliability, 28 experienced trauma and orthopedic surgeons categorized 25 anonymized cases using X-ray, CT, and MRI scans twice via online surveys. A period of 4 weeks separated the completion of the first from the second survey, and the cases were presented in an altered order. While 13 of the raters were also involved in developing the CS (developing raters (DR)), 15 user raters (UR) were not deeply involved in the development process. To assess the interRR of the OF-Pelvis categories, Fleiss' kappa (κF) was calculated for each survey. The intraRR for both surveys was calculated for each rater using Kendall's tau (τK). The presence of a modifier was calculated with κF for interRR and Cohen's kappa (κC) for intraRR. RESULTS: The OF-Pelvis consists of five subgroups and three modifiers. Instability increases from subgroups 1 (OF1) to 5 (OF5) and by a given modifier. The three modifiers can be assigned alone or in combination. In both surveys, the interRR for subgroups was substantial: κF = 0.764 (Survey 1) and κF = 0.790 (Survey 2). The interRR of the DR and UR was nearly on par (κF Survey 1/Survey 2: DR 0.776/0.813; UR 0.748/0.766). The agreement for each of the five subgroups was also strong (κF min.-max. Survey 1/Survey 2: 0.708-0.827/0.747-0.852). The existence of at least one modifier was rated with substantial agreement (κF Survey 1/Survey 2: 0.646/0.629). The intraRR for subgroups showed almost perfect agreement (τK = 0.894, DR: τK = 0.901, UR: τK = 0.889). The modifier had an intraRR of κC = 0.684 (DR: κC = 0.723, UR: κC = 0.651), which is also considered substantial. CONCLUSION: The OF-Pelvis is a reliable tool to categorize OFP with substantial interRR and almost perfect intraRR. The similar reliabilities between experienced DRs and URs demonstrate that the training status of the user is not important. However, it may be a reliable basis for an indication of the treatment score.

[Guideline-conform treatment of injuries to the subaxial cervical spine]. / Leitliniengerechte Therapie von Verletzungen der subaxialen Halswirbelsäule.

Injuries to the subaxial cervical spine are increasing and have an increased neurological risk compared to the thoracic and lumbar spines. The current treatment recommendations according to the therapeutic recommendations of the Spine Section of the German Society for Orthopedics and Trauma Surgery (DGOU) as well as the S1 guidelines of the German Trauma Society (DGU) are presented. This second part of the article describes the correct indications and treatment planning for injuries to the cervical spine. Based on the AOSpine classification for subaxial cervical spine injuries, decisions can be made about conservative or surgical treatment as well as individual details of the treatment. The underlying principles of treatment are relief of neurological structures, restoration of stability and reconstruction/preservation of the physiological alignment.

[Guideline-conform diagnostics for injuries of the subaxial cervical spine]. / Leitliniengerechte Diagnostik bei Verletzungen der subaxialen Halswirbelsäule.

Injuries to the subaxial cervical spine are increasing and have a high risk for neurological injury in comparison to the thoracic and lumbar spine. The current treatment recommendations according to the recommendations of the section spine of the German Society for Orthopaedics and Trauma (DGOU) and the S1 guidelines of the German Society for Trauma Surgery are summarized in this article. High-energy as well as low-energy trauma can cause a significant injury to the cervical spine. If there is a suspicion of a cervical spine injury, a tomographic imaging modality (CT/MRI) is the procedure of choice. Injuries should be classified according to the AOSpine classification for subaxial injuries. Based on this classification, a decision on a conservative or operative treatment regimen as well as individual details of the treatment can be made.

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.

[Conservative Treatment of Thoracic and Lumbar Vertebral Fractures - what's it all about?] / Konservative Behandlung von Wirbelfrakturen in BWS und LWS ­ was geht wie?

The basis for assessing thoracolumbar vertebral body fractures are two established classification systems. Important, especially in terms of further treatment, is the distinction between osteoporotic and healthy bones. The AO Spine classification offers a comprehensive tool for healthy bones to reliably specify the morphological criterias (alignment, integrity of the intervertebral disc, fragment separation, stenosis of the spinal canal). In addition to the fracture morphology, the OF classification for osteoporotic fractures includes patient-specific characteristics to initiate adequate therapy. In general an adequate pain therapy is required for early rehabilitation. While in the bone healthy population, physiotherapy reduces the risk of muscle deconditioning, in the osteoporotic population it additionally serves to prevent subsequent fractures. Unlike osteoporotic patients, bone healthy patients with vertebral fractures should not undergo a corset/orthosis treatment.

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.

The C2-Pars Interarticularis Screw as an Alternative in Atlanto-Axial Stabilization. A Biomechanical Comparison of Established Techniques.

AIM: To compare four different atlantoaxial stabilization techniques. MATERIAL AND METHODS: Eight human cervical spines (segments C0-C3) were tested in flexion/extension, lateral bending and axial rotation. Range of Motion (ROM) at a 1.5 Nm load was recorded. After native testing, the Harms (HARMS), pars screw (PARS), intralaminar screw (INTRA) and anterior transarticular screw (ATA) constructs were applied in a random order. RESULTS: FLEXION/EXTENSION: mean ROM (±SD) in native state was 15.9° (± 7.6°); HARMS 3.6° (± 2.0°); INTRA 5.5° (± 2.7°); PARS 2.8° (± 1.6°); ATA 3.7° (± 1.3°). A significant difference was found for all techniques compared to the native spine. LATERAL BENDING: ROM in native state was 3.2° (± 1.9°); HARMS 1.4° (± 0.4°); INTRA 2.5° (± 1.4°); PARS 1.3° (± 0.7°); ATA 0.9° (± 0.6°). There were no significant differences compared to native spine, although ATA and PARS showed a strong tendency. INTRA had a significantly higher ROM than ATA. AXIAL ROTATION: ROM in native state was 15.7° (± 6.6°); HARMS 1.5° (± 0.7); INTRA 2.7° (± 2.1°); PARS 1.7° (± 0.7); ATA 1.1° (± 0.3°). All instrumentation techniques significantly reduced ROM; there was no significant difference between the techniques. All instrumentation techniques were able to reduce ROM for most of the motions. The differences between the techniques were small. Nevertheless, the intralaminar screw showed deficits in lateral bending. CONCLUSION: Screw positioning seems to be of minor influence on stability in atlantoaxial stabilization. Therefore, the pars screw is a sound alternative to the established techniques from a biomechanical point of view. Anatomical considerations for screw placement should be kept in mind as a superior priority.

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

STUDY DESIGN: Narrative literature review and expert recommendation. OBJECTIVE: To establish treatment recommendations for axis ring fractures based on the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma. METHODS: This recommendation summarizes the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma with regard to the treatment of axis ring fractures based on a narrative literature review. RESULTS: Typical "hangman's fractures" with bilateral separation of the neural arch from C2 and atypical "hangman's fractures" with irregular fracture morphology are described. Computed tomography is the "gold" standard used to detect and analyse these fractures adequately. Furthermore, the detection of vertebral artery integrity is necessary. To classify axis ring fractures, the Levine-Edwards or Josten classification is recommended. In particular, the integrity of the C2/3 disc and the integrity of the anterior longitudinal ligament are used to determine the treatment strategy. While Levine-Edwards type I and type IIA (Josten type 1 and 2) fractures should be treated conservatively, Levine type II and type III (Josten type 3 and 4) fractures should be treated operatively. Levine-Edwards type II fractures will be predominately treated by anterior C2/3 fusion. Levine-Edwards type III fractures have to be primary reduced, if an anterior fusion is planned (anterior cervical discectomy and fusion [ACDF] C2/3). If a closed reduction of a type III fracture is impossible, an open reduction and posterior fixation/fusion is the treatment of choice. CONCLUSION: Conservative treatment is predominantly reserved for Levine-Edwards I and IIA fractures. Operative treatment should be performed in case of Levine-Edwards II and III fractures.

Treatment of Injuries to the Subaxial Cervical Spine: Recommendations of the Spine Section of the German Society for Orthopaedics and Trauma (DGOU).

STUDY DESIGN: Expert consensus. OBJECTIVES: To establish treatment recommendations for subaxial cervical spine injuries based on current literature and the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma. METHODS: This recommendation summarizes the knowledge of the Spine Section of the German Society for Orthopaedics and Trauma. RESULTS: Therapeutic goals are a stable, painless cervical spine and protection against secondary neurologic damage while retaining maximum possible motion and spinal profile. The AOSpine classification for subaxial cervical injuries is recommended. The Canadian C-Spine Rule is recommended to decide on the need for imaging. Computed tomography is the favoured modality. Conventional x-ray is preserved for cases lacking a "dangerous mechanism of injury." Magnetic resonance imaging is recommended in case of unexplained neurologic deficit, prior to closed reduction and to exclude disco-ligamentous injuries. Computed tomography angiography is recommended in high-grade facet joint injuries or in the presence of vertebra-basilar symptoms. A0-, A1- and A2-injuries are treated conservatively, but have to be monitored for progressive kyphosis. A3 injuries are operated in the majority of cases. A4- and B- and C-type injuries are treated surgically. Most injuries can be treated with anterior plate stabilization and interbody support; A4 fractures need vertebral body replacement. In certain cases, additive or pure posterior instrumentation is needed. Usually, lateral mass screws suffice. A navigation system is advised for pedicle screws from C3 to C6. CONCLUSIONS: These recommendations provide a framework for the treatment of subaxial cervical spine Injuries. They give advice about diagnostic measures and the therapeutic strategy.

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.

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

STUDY DESIGN: Narrative review and expert recommendation. OBJECTIVES: To establish treatment recommendations for atlas fractures based on the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma. METHODS: Neither high-level evidence studies comparing conservative and operative management nor studies matching different operative treatment strategies exist. This recommendation summarizes the knowledge of the experts of the Spine Section of the German Society for Orthopaedics and Trauma with regard to the treatment of atlas fractures. RESULTS: Most atlas fractures are the result of compression forces. A valuable morphological classification system has been described by Gehweiler. For an adequate diagnosis, a computed tomography is mandatory. To distinguish between stable and unstable type 3 injuries, it is necessary to evaluate the integrity of the transverse atlantal ligament (TAL) with magnetic resonance imaging and to classify the TAL lesions. The majority of atlas fractures are stable and will be successfully managed conservatively. Unstable atlas fractures (type 3b and sagittal split type 4 fractures) should be treated by surgical stabilization. Unstable atlas fractures (type 3b) with a midsubstance ligamentous disruption or severely dislocated ligamentous bony avulsions of the TAL can successfully be treated by a C1/2 fusion. Unstable atlas fractures (type 3b) with a moderately dislocated ligamentous bony avulsion of the TAL and sagittal split type 4 fractures may be treated by atlas osteosynthesis only. CONCLUSIONS: Whereas the majority of atlas fractures can be managed conservatively, in specific fracture patterns surgical treatment strategies have become the standard of care.

Safe management of acute cervical spine injuries.

Cervical spine injuries are frequent and often caused by a blunt trauma mechanism. They can have severe consequences, with a high mortality rate and a high rate of neurological lesions.Diagnosis is a three-step process: 1) risk assessment according to the history and clinical features, guided by a clinical decision rule such as the Canadian C-Spine rule; 2) imaging if needed; 3) classification of the injury according to different classification systems in the different regions of the cervical spine.The urgency of treatment is dependent on the presence of a neurological lesion and/or instability. The treatment strategy depends on the morphological criteria as defined by the classification. Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170076.

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.

[Subaxial Cervical Spine Injuries: Treatment Recommendations of the German Orthopedic and Trauma Society]. / Therapieempfehlungen zur Versorgung von Verletzungen der subaxialen Halswirbelsäule.

In a consensus process during four sessions in 2016, the working group "lower cervical spine" of the German Society for Orthopedic and Trauma Surgery (DGOU), formulated "Therapeutic Recommendations for the Lower Cervical Spine", taking into consideration the current literature. Therapeutic goals are a permanently stable, painless cervical spine and the protection against secondary neurologic damage while retaining the greatest possible amount of motion and spinal profile. Due to its ease of use and its proven good reliability, the AOSpine classification for subaxial cervical injuries should be used. The Canadian C-Spine Rule is recommended as a clinical decision rule whether to perform imaging or not. If a structural or unstable injury is suspected by patient history or clinical findings, a spiral CT scan of the cervical spine is the favoured diagnostic modality. Conventional X-ray is reserved for patients in whom there is no "dangerous mechanism of injury". MR imaging is recommended in case of unexplained neurologic deficit, prior to closed reduction and open posterior surgery and to exclude disco-ligamentous injuries. Urgency of MR imaging depends on the specific findings. CT angiography is recommended in higher-grade facet joint injuries or in the presence of vertebra-basilar symptoms. Flexion-extension imaging is recommended only as a physician-guided dynamic fluoroscopy, when an unstable lesion is still suspected. The therapeutic strategy is mainly dependent on morphologic criteria, which are described using the AOSpine classification. A0-injuries are treated conservatively. A1- and A2-injuries are treated conservatively in the majority of cases, and in single cases a gross kyphotic deformity might indicate surgical stabilisation. A3-injuries do indicate a surgical therapy in the majority of cases, but certain cases might be treated conservatively. A4-fractures as well as B- and C-type injuries are to be treated surgically. Most injuries can be treated by anterior plate stabilisation with interbody support; when a complete burst fracture is present, corpectomy and vertebral body replacement is necessary. In certain cases, an additive posterior or pure posterior instrumentation might be possible or even mandatory. In most of these cases, lateral mass screws are sufficient; when pedicle screws are applied in C3 to C6, a 3D-navigation system is recommended. Injuries in an ankylosing spine (M3-modifier) should be treated preferably from posterior with long-segment instrumentation.

Traumatic Spondylolisthesis of the Axis Vertebra in Adults.

Study Design Narrative review. Objective To elucidate the current concepts in diagnosis and treatment of traumatic spondylolisthesis of the axis. Methods Literature review using PubMed, Google Scholar, and Cochrane databases. Results The traumatic spondylolisthesis of the axis accounts to 5% of all cervical spine injuries and is defined by a bilateral separation of the C2 vertebral body from the neural arch. The precise location of the fracture line may vary widely. For understanding the pathobiomechanics, the involvement of the C2-C3 disk is essential. Although its synonym "hangman's fracture" suggests an extension moment as primary injury mechanism, flexion moments are also proven to cause such fracture morphology. The axial force vector (distraction versus compression) is thought to have a significant effect on the neurologic involvement. The most widely accepted classifications, according to Effendi and modified by Levine, regard the displacement of the C2 vertebral body and possible locking of the facet joints. For decisions on conservative versus surgical therapy, a definitive statement about the stability is essential. The stability is determined by involvement of the C2-C3 disk and longitudinal ligaments, which frequently cannot be assessed by X-ray or computed tomography alone. The assessment of this soft tissue injury therefore requires additional imaging either by magnetic resonance imaging to display the disk and longitudinal ligaments or dynamic fluoroscopy to assess functional behavior of the C2-C3 motion segment. If stability is proven, an immobilization of the cervical spine in a semirigid cervical collar is sufficient. Unstable lesions require surgical stabilization. The standard procedure is an anterior C2-C3 diskectomy and fusion, because of the lower morbidity of the anterior approach and the motion preservation between C1 and C2. In rare cases (irreducible locked facet joints, the necessity of decompression of the vertebral artery, contraindication for anterior approach), a posterior approach is sometimes necessary. Isolated direct screw osteosynthesis is of little value, because it only makes sense in cases with an intact C2-C3 disk, which is usually regarded as stable and therefore might be treated conservatively. Conclusions Overall, the clinical evidence regarding traumatic spondylolisthesis of the axis is very low and mainly based on small case series, expert opinion, laboratory findings, and theoretical considerations.

A zero-profile anchored spacer in multilevel cervical anterior interbody fusion: biomechanical comparison to established fixation techniques.

STUDY DESIGN: In vitro biomechanical analysis of different multilevel cervical fixation techniques. OBJECTIVE: To compare the multilevel stability of a cervical anchored spacer (AS) with established fixation techniques. SUMMARY OF BACKGROUND DATA: To avoid plate-related complications, for example, dysphagia zero-profile AS has been developed. The use of these new zero-profile implants for treatment of cervical degenerative disc disease is widely accepted after encouraging biomechanical results for single-level instrumentation. However, there is only little knowledge about the biomechanical stability of these zero-profile devices in multilevel instrumentations. METHODS: Eight fresh-frozen human cadaveric cervical spines (C3-C7) were nondestructively tested in a biomechanical 3-dimensional spine test setup. Segmental range of motion (ROM) under torsional load of 1.5 N·m was measured optoelectronically. Intact spine baseline measurement specimens were tested with 2- and 3-level instrumentation including (1) stand-alone PEEK-cage; (2) PEEK-cage plus locking plate; and (3) AS. Repeated-measures analyses of variance were used for statistical analysis. RESULTS: Comparison of baseline ROM and stand-alone PEEK-cage instrumentation showed a significant lower segmental ROM only for 2-level instrumentations. Cage plus plate and AS were able to reduce segmental ROM significantly (P < 0.05) in 2- and 3-level instrumentations. Comparing cage plus plate and AS, a significant lower ROM was detected for flexion/extension in 2- and 3-level instrumentation and for lateral bending in 2-level instrumentation using cage plus plate. CONCLUSION: Segmental stability decreases with the number of instrumented segments regardless of the used implant. Comparing the different fixation techniques biomechanically, the locking plate and cage construct was stiffer in all test modes than the anchored devices in multilevel constructs. However, it remains unclear what the clinical significance may be. LEVEL OF EVIDENCE: N/A.