Clinimetric study and review of the Reaction Level Scale.

OBJECTIVES: Although the Reaction Level Scale (RLS) is still used for the assessment of the level of consciousness in distinct centers, its clinical characteristics and significance have been incompletely researched. In the current study, the clinimetric properties, the prognostic value, and the impact of the raters' background on the application of the RLS, in comparison with the Glasgow Coma Scale (GCS), are investigated. MATERIALS AND METHODS: A systematic review on the available clinical evidence for the RLS was first carried out. Next, the RLS was translated into Greek, and patients with neurosurgical pathologies in need of consciousness monitoring were independently assessed with both RLS and GCS, by four raters (two consultants, one resident, and one nurse) within one hour. Interrater reliability, construct validity, and predictive value (mortality and poor outcome, at discharge and at 6 months) were evaluated. RESULTS: Literature review retrieved 9 clinimetric studies related to the RLS, most of low quality, indicating that the scale has not been thoroughly studied. Both versions of the RLS (original and modified) showed high interrater reliability (κw >0.80 for all pairs of raters), construct validity (Spearman's p > .90 for all raters), and prognostic value (areas under the curve >0.85 for all raters and outcomes). However, except for broader patients' coverage, it failed to show any advantage over the GCS. CONCLUSIONS: The RLS has not succeeded in showing any advantage over the GCS in terms of reliability and validity. Available evidence cannot justify its use in clinical practice as a substitute to the widely applied GCS.

A systematic review on the outcome of intramedullary spinal cord cavernous malformations.

PURPOSE: This study aimed to investigate the neurological outcome, trends and sequelae following surgical or conservative treatment of intramedullary spinal cord cavernous malformations (ISCCMs). METHODS: A systematic review was performed according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. The primary outcome measure was the change in the neurological status after surgery or conservative management. A logistic regression analysis investigating prognostic factors related to outcome was also performed. RESULTS: Twenty-one studies with 1091 patients in total were included, of which 1005 (92.1%) underwent surgical resection and 86 (7.9%) were treated conservatively. Gross total resection was achieved in 95.7% of the patients and partial resection in 4.3%. Most lesions (60.2%) were located in the thoracic spine and presented with motor (60.4%) and sensory deficits (59.7%). In the long term, surgical treatment resulted in an improved neurological status in 36.9% of the patients, in 55.8% it remained stable, and in 7.3% it deteriorated compared to the preoperative state. In the conservative cohort, 21.7% improved, 69.6% remained stable, and 8.7% deteriorated. Solitary lesions, duration of preoperative symptoms less than 3 months as well as an improved post-operative neurological status were predictors of a favourable long-term outcome. CONCLUSIONS: Whenever feasible, symptomatic patients with ISCCM are recommended to undergo surgery within 3 months from symptom onset. Absence of multiple lesions and, most importantly, post-operative symptom improvement foresee a favourable long-term outcome. Further research is warranted to discern the role of conservative treatment in symptomatic patients.

Cross-Cultural Adaptation and Validation of the Greek Version of the "Full Outline of Unresponsiveness Score": A Prospective Observational Clinimetric Study in Neurosurgical Patients.

BACKGROUND: The Full Outline of Unresponsiveness (FOUR) score is a clinical instrument for the assessment of consciousness which is gradually gaining ground in clinical practice, as it incorporates more complete neurological information than the Glasgow Coma Scale (GCS). The main objectives of the current study were the following: (1) translate and cross-culturally adapt the FOUR score into Greek; (2) evaluate its clinimetric properties, including interrater reliability, internal consistency, and construct validity; and (3) evaluate the reliability of assessments among health care professionals with different levels of experience and training. METHODS: The FOUR score was initially translated into Greek. Next, patients with neurosurgical pathologies in need of consciousness monitoring were independently assessed with the GCS and FOUR score within one hour by four raters who had different levels of experience and training (two board-certified neurosurgeons, a neurosurgery resident, and a registered nurse). Interrater reliability, internal consistency, and construct validity were evaluated for the scales using weighted Cohen's κ (κw) and intraclass correlation coefficients (ICC), Cronbach's α and Spearman's ρ values, respectively. RESULTS: A total of 408 assessments were performed for 99 patients. The interrater reliability was excellent for both the FOUR score (ICC = 0.941) and GCS (ICC = 0.936). The values of κw exceeded 0.90 for all pairs, suggesting that the FOUR score can be reliably applied by raters with varying experience. Among the scales' components, FOUR score's brainstem and respiratory items showed the lowest, yet high enough (κw > 0.60), level of agreement. The interrater reliability remained excellent (κw > 0.85, ICC > 0.90) for all diagnosis and age groups, with a trend toward higher FOUR score values in the most severe cases (ICC = 0.813 vs. 0.723). Both the FOUR score and GCS showed high internal consistency (Cronbach's α > 0.70 for all occasions). The FOUR score correlated strongly with GCS (Spearman's ρ > 0.90 for all raters), suggesting high construct validity. CONCLUSIONS: The Greek version of the FOUR score is a valid and reliable tool for the clinical assessment of patients with disorders of consciousness. It can be applied successfully by nurses, residents, and specialized physicians. Therefore, its use by medical practitioners with different levels of experience and training is strongly encouraged.

Cerebrospinal fluid levels of GFAP and pNF-H are elevated in patients with chronic spinal cord injury and neurological deterioration.

BACKGROUND: Years after a traumatic spinal cord injury (SCI), a subset of patients may develop progressive clinical deterioration due to intradural scar formation and spinal cord tethering, with or without an associated syringomyelia. Meningitis, intradural hemorrhages, or intradural tumor surgery may also trigger glial scar formation and spinal cord tethering, leading to neurological worsening. Surgery is the treatment of choice in these chronic SCI patients. OBJECTIVE: We hypothesized that cerebrospinal fluid (CSF) and plasma biomarkers could track ongoing neuronal loss and scar formation in patients with spinal cord tethering and are associated with clinical symptoms. METHODS: We prospectively enrolled 12 patients with spinal cord tethering and measured glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase L1 (UCH-L1), and phosphorylated Neurofilament-heavy (pNF-H) in CSF and blood. Seven patients with benign lumbar intradural tumors and 7 patients with cervical radiculopathy without spinal cord involvement served as controls. RESULTS: All evaluated biomarker levels were markedly higher in CSF than in plasma, without any correlation between the two compartments. When compared with radiculopathy controls, CSF GFAP and pNF-H levels were higher in patients with spinal cord tethering (p ≤ 0.05). In contrast, CSF UCH-L1 levels were not altered in chronic SCI patients when compared with either control groups. CONCLUSIONS: The present findings suggest that in patients with spinal cord tethering, CSF GFAP and pNF-H levels might reflect ongoing scar formation and neuronal injury potentially responsible for progressive neurological deterioration.

Infantile Atypical Teratoid Rhabdoid Tumor of the Spine Presenting with Acute Hydrocephalus.

INTRODUCTION: Central nervous system atypical teratoid rhabdoid tumors (ATRTs) are aggressive lesions usually presenting during the first 3 years of life. These tumors have a dismal prognosis with most patients dying within 1 year from presentation. Primary spinal location in infants is very rare. CASE PRESENTATION: We report a case of a 4-month-old boy who presented with a history of hypotonia, poor head control, and gradually reduced level of consciousness, over the past week. Computed tomography (CT) showed acute hydrocephalus with no underlying intracranial pathology. A ventriculoperitoneal shunt was inserted acutely. Postoperatively, ventilator weaning was unsuccessful. MRI of the brain and whole spine revealed an intraspinal extradural contrast-enhancing heterogenous mass in the subaxial cervical spine extending to the thoracic cavity. A biopsy was taken through a transthoracic approach, and histopathology confirmed the diagnosis of ATRT. Several cycles of radiation therapy and chemotherapy were given but the tumor progressed both locally and intracranially. Eventually, pupils became dilated and fixed. Brain CT scan showed widespread ischemic lesions and an extensive intracranial tumor extension with massive bleeding. The child eventually died 110 days after admission. CONCLUSIONS: In infants presenting with acute hydrocephalus where an obvious intracranial cause is not detected, the whole neuraxis should be screened. However, despite aggressive measures and advances in multimodality treatment, prognosis of ATRT remains dismal.

Differences in neurosurgical treatment of intracerebral haemorrhage: a nation-wide observational study of 578 consecutive patients.

BACKGROUND: Supratentorial intracerebral haemorrhage (ICH) carries an excessive mortality and morbidity. Although surgical ICH treatment can be life-saving, the indications for surgery in larger cohorts of ICH patients are controversial and not well defined. We hypothesised that surgical indications vary substantially among neurosurgical centres in Sweden. OBJECTIVE: In this nation-wide retrospective observational study, differences in treatment strategies among all neurosurgical departments in Sweden were evaluated. METHODS: Patient records, neuroimaging and clinical outcome focused on 30-day mortality were collected on each operated ICH patient treated at any of the six neurosurgical centres in Sweden from 1 January 2011 to 31 December 2015. RESULTS: In total, 578 consecutive surgically treated ICH patients were evaluated. There was a similar incidence of surgical treatment among different neurosurgical catchment areas. Patient selection for surgery was similar among the centres in terms of patient age, pre-operative level of consciousness and co-morbidities, but differed in ICH volume, proportion of deep-seated vs. lobar ICH and pre-operative signs of herniation (p < .05). Post-operative patient management strategies, including the use of ICP-monitoring, CSF-drainage and mechanical ventilation, varied among centres (p < .05). The 30-day mortality ranged between 10 and 28%. CONCLUSIONS: Although indications for surgical treatment of ICH in the six Swedish neurosurgical centres were homogenous with regard to age and pre-operative level of consciousness, important differences in ICH volume, proportion of deep-seated haemorrhages and pre-operative signs of herniation were observed, and there was a substantial variability in post-operative management. The present results reflect the need for refined evidence-based guidelines for surgical management of ICH.

Atlas posterior arch and vertebral artery's groove variants: a classification, morphometric study, clinical and surgical implications.

BACKGROUND: The third part of the vertebral artery (VA) coursing in vertebral artery groove (VAG) may be injured during posterior craniocervical junction approaches. OBJECTIVE: The current study classifies all possible variants of the posterior arch (PA) of the atlas vertebra (C1), focusing on VAG and calculates their incidence. PA and VAG morphometry is studied in correlation with gender and age. Clinical and surgical implications of recorded variants are provided in an effort to explain associated pathology. The usefulness of three-dimensional computed tomography (3D-CT) in detecting PA variants is highlighted. MATERIALS AND METHODS: Two hundred and forty-four Greek adult dry C1 were classified in types according to PA morphology [i.e. presence of an imprint or a distinct VAG and occurrence of a partially or completely ossified dorsal (PDP or CDP) or lateral (PLP or CLP) ponticle unilaterally or bilaterally]. Combined variants were also included. RESULTS: A VAG and an imprint were detected in 42.62% and 15.16%. A PDP and CDP were observed in 18.03% and 15.98%, while a CLP and PLP in 2.05% and 1.64%, respectively. Combined PDP and PLP were detected in 2.05%, a CDP and CLP similarly to a CDP and PLP in 1.23% and a PDP and CLP in 0.40%. CONCLUSIONS: Variants' classification will contribute to an in depth understanding of the complex C1 anatomy and may explain cases of VA entrapment and injury during PA fixation. Surgeons should carefully study 3D-CT imaging to ensure type, location, size and shape of C1 ponticles in combination with VAG morphology and VA course before screw insertion.

Neurosurgical untethering with or without syrinx drainage results in high patient satisfaction and favorable clinical outcome in post-traumatic myelopathy patients.

STUDY DESIGN: Retrospective data collection and patient-reported outcome measures. OBJECTIVES: To investigate surgical outcome, complications, and patient satisfaction in patients with chronic SCI and symptomatic post-traumatic progressive myelopathy (PPM) who underwent neurosurgical untethering and/or spinal cord cyst drainage with the aim of preventing further neurological deterioration. SETTING: Single-center study at an academic neurosurgery department. METHODS: All SCI patients who underwent neurosurgery between 1996 and 2013 were retrospectively included. All medical charts and the treating surgeon's operative reports were reviewed to identify surgical indications, surgical technique, and post-operative complications. A questionnaire and an EQ-5D-instrument were used to assess patient's self-described health status and satisfaction at long-term follow-up. RESULTS: Fifty-two patients (43 men, 9 women) were identified, of whom five were dead and one was lost to follow-up. Main indications for surgery were pain (54%), motor (37%), or sensory (8%) impairment, and spasticity (2.0%). Overall complications were rare (8%). At follow-up, the subjectively perceived outcome was improved in 24 and remained unchanged in 21 patients. Thus, the surgical aim was met in 87% of patients. Of the 46 eligible patients, 38 responded to the questionnaire of whom 65% were satisfied with the surgical results. Patients with cervical lesions were more satisfied with the surgical treatment than patients with thoracic/thoracolumbar lesions (p = 0.05). CONCLUSIONS: Neurosurgical untethering and/or cyst drainage in chronic SCI patients and PPM resulted in a high degree of patient satisfaction, particularly in cervical SCI patients with minimal complications.

Favorable clinical outcome following surgical evacuation of deep-seated and lobar supratentorial intracerebral hemorrhage: a retrospective single-center analysis of 123 cases.

BACKGROUND: In spontaneous supratentorial intracerebral hemorrhage (ICH), the role of surgical treatment remains controversial, particularly in deep-seated ICHs. We hypothesized that early mortality and long-term functional outcome differ between patients with surgically treated lobar and deep-seated ICH. METHOD: Patients who underwent craniotomy for ICH evacuation from 2009 to 2015 were retrospectively evaluated and categorized into two subgroups: lobar and deep-seated ICH. The modified Rankin Scale (mRS) was used to evaluate long-term functional outcome. RESULT: Of the 123 patients operated for ICH, 49.6% (n = 61) had lobar and 50.4% (n = 62) deep-seated ICH. At long-term follow-up (mean 4.2 years), 25 patients (20.3%) were dead, while 51.0% of survivors had a favorable outcome (mRS score ≤ 3). Overall mortality was 13.0% at 30 days and 17.9% at 6 months post-ictus, not influenced by ICH location. Mortality was higher in patients ≥ 65 years old (p = 0.020). The deep-seated group had higher incidence and extent of intraventricular extension, younger age (52.6 ± 9.0 years vs. 58.5 ± 9.8 years; p < 0.05), more frequently pupillary abnormalities, and longer neurocritical care stay (p < 0.05). The proportion of patients with good outcome was 48.0% in deep-seated vs. 54.1% in lobar ICH (p = 0.552). In lobar ICH, independent predictors of long-term outcome were age, hemorrhage volume, preoperative level of consciousness, and pupillary reaction. In deep-seated ICHs, only high age correlated significantly with poor outcome. CONCLUSIONS: At long-term follow-up, most ICH survivors had a favorable clinical outcome. Neither mortality nor long-term functional outcome differed between patients operated for lobar or deep-seated ICH. A combination of surgery and neurocritical care can result in favorable clinical outcome, regardless of ICH location.

Hands train the brain-what is the role of hand tremor and anxiety in undergraduate microsurgical skills?

INTRODUCTION: Physiological hand tremor occurs naturally, due to oscillations of the upper extremities. Tremor can be exacerbated by stress and anxiety, interfering with fine motor tasks and potentially impact on surgical performance, particularly in microsurgery. We investigated the link between tremor, anxiety and performance in a neurosurgical module as part of an international surgical course. METHODS: Essential Skills in the Management of Surgical Cases (ESMSC) course recruits medical students from European Union (EU) medical schools. Students are asked to suture the dura mater in an ex vivo swine model, of which the first suture completed was assessed. Questionnaires were distributed before and after the module, eliciting tremor risk factors, self-perception of tremor and anxiety. Johnson O'Connor dexterity pad was used to objectively measure dexterity. Direct Observation of Procedural Skills (DOPS) was used to assess skills-based performance. Anxiety was assessed using the Westside Test Anxiety Scale (WTAS). Tremor was evaluated by four qualified neurosurgeons. RESULTS: Forty delegates participated in the study. Overall performance decreased with greater subjective perception of anxiety (p = 0.032, rho = - 0.392). Although increasing scores for tremor at rest and overall WTAS score were associated with decreased performance, this was not statistically significant (p > 0.05). Tremor at rest did not affect dexterity (p = 0.876, rho = - 0.027). CONCLUSIONS: Physiological tremor did not affect student performance and microsurgical dexterity in a simulation-based environment. Self-perception of anxiety affected performance in this module, suggesting that more confident students perform better in a simulated neurosurgical setting.

Congenital Glioblastoma Multiforme: An Unusual and Challenging Tumor.

Congenital glioblastoma multiforme is a rare tumor of the central nervous system with unique features. The existing evidence on its pathogenesis, genetic and molecular profile, special characteristics, treatment, and prognosis is reviewed. An increased number of antenatal diagnoses and prolonged survival for those individuals who can tolerate combined surgical resection and chemotherapy has been noted. The overall prognosis, however, remains poor. A better understanding of this unusual entity is important. Further research is needed to discern tumor's pathogenesis and natural history. This will likely lead to the development and implementation of treatment strategies that may decrease mortality and morbidity in these patients.

Nosocomial bloodstream infections in neurosurgery: a 10-year analysis in a center with high antimicrobial drug-resistance prevalence.

BACKGROUND: Data on nosocomial bloodstream infections (NBSI) in neurosurgery is limited. This study aimed to analyze the epidemiology, microbiology, outcome, and risk factors for death in neurosurgical patients with NBSI in a multidrug resistant setting. METHODS: Neurosurgical patients with a confirmed NBSI within the period 2003-2012 were retrospectively analyzed. NBSI was diagnosed when a pathogen was isolated from a blood sample obtained after the first 48 h of hospitalization. Patients' demographic, clinical, and microbiological data were recorded and analyzed using univariate and multivariate analysis. RESULTS: A total of 236 patients with NBSI were identified and 378 isolates were recovered from blood cultures. Incidence of NBSI was 4.3 infections/1000 bed-days. Gram-negative bacteria slightly predominated (54.5 %). The commonest bacteria were coagulase-negative staphylococci (CoNS, 26 %), Klebsiella pneumoniae (15.3 %), Pseudomonas aeruginosa (14.8 %), and Acinetobacter baumannii (13.2 %). Carbapenem resistance was found in 90 % of A. baumannii, in 66 % of P. aeruginosa, and in 22 % (2003-2007) to 77 % (2008-2012) of K. pneumoniae isolates (p < 0.05). Most CoNS and Staphylococcus aureus isolates (94 and 80 %, respectively) were methicillin-resistant. All Gram-negative isolates were sensitive to colistin and all Gram-positive isolates were sensitive to vancomycin and linezolid. Antimicrobial consumption decreased after 2007 (p < 0.05). Overall mortality was 50.4 %. In multivariate analysis, advanced age and stay in an Intermediate Care Unit (IMCU) were independent risk factors for in-hospital mortality (p < 0.05). CONCLUSIONS: Overall, high incidence of NBSI and considerable resistance of Gram-positive and particularly Gram-negative bacteria were noted in neurosurgical patients. Mortality was high with advanced age and stay in IMCU being the most important death-related factors.

Dermal Sinus Tract of the Thoracic Spine Presenting with Intramedullary Abscess and Cranial Nerve Deficits.

Congenital dermal sinus tract of the spine is an unusual developmental defect which represents a failure of the surface ectoderm and dermal elements to separate from the neuroectoderm. A 15-month-old female presented with high fever, severe right hemiparesis, difficulty breathing and cranial nerve deficits. Magnetic resonance imaging (MRI) of the spine revealed a congenital dermal sinus tract at the Th6 level, an intramedullary collection extending up to the brainstem and a probable intramedullary cystic lesion. The child was operated acutely with ligation of the sinus tract, drainage of the abscess and partial removal of the intramedullary lesion. Due to abscess recurrence, she was reoperated with complete excision of the dermal sinus tract, abscess redrainage and subtotal excision of the dermoid cyst (retaining a part of its capsule). Pus culture isolated Corynebacterium species and Peptococcus species and histology of the lesion showed a dermoid cyst. Postoperatively, after an initial neurologic deterioration, she progressively improved. An MRI scan at 15 months neither showed recurrence of the collection nor regrowth of the lesion. Spinal dermal sinus tracts that remain unnoticed or untreated can result in serious complications and should be operated as soon as possible to prevent undesirable sequelae.

The neurological wake-up test does not alter cerebral energy metabolism and oxygenation in patients with severe traumatic brain injury.

BACKGROUND: The neurological wake-up test (NWT) is used to monitor the level of consciousness in patients with traumatic brain injury (TBI). However, it requires interruption of sedation and may elicit a stress response. We evaluated the effects of the NWT using cerebral microdialysis (MD), brain tissue oxygenation (PbtiO2), jugular venous oxygen saturation (SjvO2), and/or arterial-venous difference (AVD) for glucose, lactate, and oxygen in patients with severe TBI. METHODS: Seventeen intubated TBI patients (age 16-74 years) were sedated using continuous propofol infusion. All patients received intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring in addition to MD, PbtiO2 and/or SjvO2. Up to 10 days post-injury, ICP, CPP, PbtiO2 (51 NWTs), MD (49 NWTs), and/or SjvO2 (18 NWTs) levels during propofol sedation (baseline) and NWT were compared. MD was evaluated at a flow rate of 1.0 µL/min (28 NWTs) or the routine 0.3 µL/min rate (21 NWTs). RESULTS: The NWT increased ICP and CPP levels (p < 0.05). Compared to baseline, interstitial levels of glucose, lactate, pyruvate, glutamate, glycerol, and the lactate/pyruvate ratio were unaltered by the NWT. Pathological SjvO2 (<50 % or >71 %; n = 2 NWTs) and PbtiO2 (<10 mmHg; n = 3 NWTs) values were rare at baseline and did not change following NWT. Finally, the NWT did not alter the AVD of glucose, lactate, or oxygen. CONCLUSIONS: The NWT-induced stress response resulted in increased ICP and CPP levels although it did not negatively alter focal neurochemistry or cerebral oxygenation in TBI patients.

Thickness Asymmetry of the Vertebral Artery Groove: A Dried Vertebrae Study.

BACKGROUND: The vertebral artery groove (VAG), located on the posterior arch of the first cervical (atlas) vertebra plays a pivotal role in guiding the vertebral artery's (VA) third part (V3). Deviations in VAG morphology and morphometry (dimensions) can influence vascular dynamics and pose clinical implications. AIM: The current study delves into the morphometric variants and explores the less-explored morphometric variable of the VAG thickness, highlighting possible laterality (asymmetry). METHODS: A morphometric investigation was conducted on 141 dried atlas (73 male and 68 female) vertebrae from a Greek adult population. The VAG's minimum thickness was investigated by considering the laterality (sides' differences), gender, and age impact on it. Measurements were performed by two independent researchers, ensuring the data reliability. RESULTS: A significant asymmetry was identified in the VAG thickness between the left (3.9 ± 0.9 mm) and right (4.1 ± 1.1 mm) (p=0.005) sides, with the left side having the mean minimum thickness. Gender had a significant impact on VAG thickness only on the left side, with females presenting a significantly thinner left-sided VAG (3.6 ± 0.9 mm) than males (4.10 ± 0.7 mm) (p=0.001). Age had no significant impact on the VAG thickness.  Conclusion: The present study underscores the significance of asymmetry in the VAG thickness in craniocervical interventions. This less-explored morphometric variable warrants careful consideration by surgeons during preoperative planning to minimize potential complications. The current findings highlight the importance of understanding the VAG thickness asymmetry and its clinical implications, as this osseous variable may be an index of a different diameter of the VA by side. It is recommended that surgeons incorporate this variable into their preoperative assessments to improve the safety and efficacy of craniocervical interventions.

Neurosurgery Training in Greece.

OBJECTIVE: The structure and specifics of neurosurgery residency training vary substantially across programs and countries, potentially leading to differences in clinical reasoning, surgical skills, and professionalism. The Greek neurosurgical training system is unique in numerous respects. This manuscript delineates the current state of neurosurgical residency training in Greece and outlines future directions. METHODS: A narrative review was conducted to describe the Greek neurosurgical residency training structure. The perspectives of the authors regarding challenges in training and future directions were synthesized. RESULTS: This manuscript describes the neurosurgery residency curriculum and board certification process, existing training programs, and key challenges in neurosurgery residency training in Greece. The authors propose future directions to reform neurosurgical training in Greece. CONCLUSIONS: Neurosurgery residency training in Greece has been largely unchanged for many years. This review leads to suggested modification of the existing training process may improve the quality of training and equip neurosurgeons to respond to the rapidly changing landscape of the field.

Biomechanical evaluation of a low profile, anchored cervical interbody spacer device in the setting of progressive flexion-distraction injury of the cervical spine.

INTRODUCTION: Anterior cervical decompression and fusion is a well-established procedure for treatment of degenerative disc disease and cervical trauma including flexion-distraction injuries. Low-profile interbody devices incorporating fixation have been introduced to avoid potential issues associated with dissection and traditional instrumentation. While these devices have been assessed in traditional models, they have not been evaluated in the setting of traumatic spine injury. This study investigated the ability of these devices to stabilize the subaxial cervical spine in the presence of flexion-distraction injuries of increasing severity. METHODS: Thirteen human cadaveric subaxial cervical spines (C3-C7) were tested at C5-C6 in flexion-extension, lateral bending and axial rotation in the load-control mode under ±1.5 Nm moments. Six spines were tested with locked screw configuration and seven with variable angle screw configuration. After testing the range of motion (ROM) with implanted device, progressive posterior destabilization was performed in 3 stages at C5-C6. RESULTS: The anchored spacer device with locked screw configuration significantly reduced C5-C6 flexion-extension (FE) motion from 14.8 ± 4.2 to 3.9 ± 1.8°, lateral bending (LB) from 10.3 ± 2.0 to 1.6 ± 0.8, and axial rotation (AR) from 11.0 ± 2.4 to 2.5 ± 0.8 compared with intact under (p < 0.01). The anchored spacer device with variable angle screw configuration also significantly reduced C5-C6 FE motion from 10.7 ± 1.7 to 5.5 ± 2.5°, LB from 8.3 ± 1.4 to 2.7 ± 1.0, and AR from 8.8 ± 2.7 to 4.6 ± 1.3 compared with intact (p < 0.01). The ROM of the C5-C6 segment with locked screw configuration and grade-3 F-D injury was significantly reduced from intact, with residual motions of 5.1 ± 2.1 in FE, 2.0 ± 1.1 in LB, and 3.3 ± 1.4 in AR. Conversely, the ROM of the C5-C6 segment with variable-angle screw configuration and grade-3 F-D injury was not significantly reduced from intact, with residual motions of 8.7 ± 4.5 in FE, 5.0 ± 1.6 in LB, and 9.5 ± 4.6 in AR. CONCLUSIONS: The locked screw spacer showed significantly reduced motion compared with the intact spine even in the setting of progressive flexion-distraction injury. The variable angle screw spacer did not sufficiently stabilize flexion-distraction injuries. The resulting motion for both constructs was higher than that reported in previous studies using traditional plating. Locked screw spacers may be utilized with additional external immobilization while variable angle screw spacers should not be used in patients with flexion-distraction injuries.