Application of the NSE score (Neurology-Stability-Epidural compression assessment) to establish the need for surgery in spinal metastases of elderly patients: a multicenter investigation.

PURPOSE: This retropective multicentric study aims to investigate the clinical applicability of the NSE score in the elderly, to verify the role of this tool as an easy help for decision making also for this class of patients. METHODS: All elderly patients (> 65 years) suffering from spinal metastases undergoing surgical or non-surgical treatment at the authors' Institutions between 2015 and 2022 were recruited. An agreement group (AG) and non-agreement group (NAG) were identified accordingly to the agreement between the NSE score indication and the performed treatment. Neurological status and axial pain were evaluated for both groups at follow-up (3 and 6 months). The same analysis was conducted specifically grouping patients older than 75 years. RESULTS: A strong association with improvement or preservation of clinical status (p < 0.001) at follow-up was obtained in AG. The association was not statistically significant in NAG at the 3-month follow-up (p 1.00 and 0.07 respectively) and at 6 months (p 0.293 and 0.09 respectively). The group of patients over 75 years old showed similar results in terms of statistical association between the agreement group and better outcomes. CONCLUSION: Far from the need or the aim to build dogmatic algorithms, the goal of preserving a proper performance status plays a key role in a modern oncological management: functional outcomes of the multicentric study group showed that the NSE score represents a reliable tool to establish the need for surgery also for elderly patients.

Extreme Lateral Interbody Fusion (XLIF) with Lateral Modular Plate Fixation: Preliminary Report on Clinical and Radiological Outcomes.

The lateral transpsoas approach (extreme lateral interbody fusion, or XLIF) allows surgeons to use various lordotic cage sizes to help restore intervertebral disk height, correct sagittal alignment, and improve fusion rates. The use of standalone devices has consistently raised doubts due to the high risk of complications and inadequate functional recovery that a circumferential arthrodesis can support. The recent introduction of a novel XLIF cage with adapted lateral plate fixation (XLPF) may further enhance the structural rigidity, consolidating the cage and plate into a singular modular entity. Nine patients from our surgical centers underwent a procedure of 1-level XLIF with XLPF in selected cases. We observed that XLPF does not extend the intraoperative footprint and provides immediate rigidity to the anterior column without any additional risk of complications and with minimal increased time compared to the traditional cage implant procedure. Although it has been shown that the use of interbody fusion cages with supplemental posterior fixation improves stabilization in all directions, the technique of standalone lateral cages may also have a place in spine surgery in that the stability may be sufficient in selected cases, such as junctional syndrome and in some forms of degenerative scoliosis.

Clinical outcomes, MRI evaluation and predictive factors of indirect decompression with lateral transpsoas approach for lumbar interbody fusion: a multicenter experience.

Introduction: Evaluating the effects of indirect decompression obtained through lateral lumbar interbody fusion (LLIF) by clinical improvements and radiological parameters on MRI scans. Identifying predictors of better decompression and clinical outcome. Materials and methods: From 2016 to 2019, patients who underwent single- or double-level indirect decompression LLIF were consecutively reviewed. Radiological signs of indirect decompression were evaluated in preoperative and follow-up MRI studies and were subsequently correlated to clinical data, expressed as axial/radicular pain (VAS back/leg), index of disability (Oswestry Disability Index) and clinical severity of lumbar stenosis (Swiss Spinal Stenosis Questionnaire). Results: 72 patients were enrolled. The mean follow-up was 24 months. Differences in vertebral canal area (p < 0.001), height of the foramina (p < 0.001), thickness of the yellow ligament (p = 0.001) and anterior height of the interbody space (p = 0.02) were observed. Older age (p = 0.042), presence of spondylolisthesis (p = 0.042), presence of intra-articular facet effusion (p = 0.003) and posterior height of the implanted cage (p = 0.020) positively affected the increase of the canal area. Change in root canal area (p < 0.001), height of the implanted cage (p = 0.020) and younger age (p = 0.035) were predictive factors of root pain relief, while increased vertebral canal area (p = 0.020) and height of the interbody fusion cage (p = 0.023) positively affected the severity of clinical stenosis. Conclusions: LLIF indirect decompression showed both clinical and radiological improvements. Presence and degree of spondylolisthesis, presence of intra-articular facet effusion, age of the patient and height of the cage were predictive factors of major clinical improvements.

Relationship between lumbar lordosis, pelvic parameters, PI-LL mismatch and outcome after short fusion surgery for lumbar degenerative disease. Literature review, rational and presentation of public study protocol: RELApSE study (registry for evaluation of lumbar artrodesis sagittal alignEment).

Background: Vertebral arthrodesis for degenerative pathology of the lumbar spine still remains burdened by clinical problems with significant negative results. The introduction of the sagittal balance assessment with the evaluation of the meaning of pelvic parameters and spinopelvic (PI-LL) mismatch offered new evaluation criteria for this widespread pathology, but there is a lack of consistent evidence on long-term outcome. Methods: The authors performed an extensive systematic review of literature, with the aim to identify all potentially relevant studies about the role and usefulness of the restoration or the assessment of Sagittal balance in lumbar degenerative disease. They present the study protocol RELApSE (NCT05448092 ID) and discuss the rationale through a comprehensive literature review. Results: From the 237 papers on this topic, a total of 176 articles were selected in this review. The analysis of these literature data shows sparse and variable evidence. There are no observations or guidelines about the value of lordosis restoration or PI-LL mismatch. Most of the works in the literature are retrospective, monocentric, based on small populations, and often address the topic evaluation partially. Conclusions: The RELApSE study is based on the possibility of comparing a heterogeneous population by pathology and different surgical technical options on some homogeneous clinical and anatomic-radiological measures aiming to understanding the value that global lumbar and segmental lordosis, distribution of lordosis, pelvic tilt, and PI-LL mismatch may have on clinical outcome in lumbar degenerative pathology and on the occurrence of adjacent segment disease.

Spinal epidural capillary hemangioma: case report and review of the literature.

BACKGROUND: Almost all of the epidural hemangiomas reported are cavernous hemangiomas. Purely extradural spinal capillary hemangiomas are very rare. Capillary hemangiomas are hamartomatous malformations that result from proliferations of vascular endothelial cells. Only ten cases have been reported in the English literature, treated with surgical excision. CASE DESCRIPTION: A case of a dorsal extradural spinal capillary hemangioma is described. A total surgical removal has been performed after spinal angiography and embolization. Complete surgical removal should always be the goal in these lesions. Embolization did not show to reduce bleeding during the surgical procedure in this case.

Posterior arch reconstruction in cervical surgery to restore the global biomechanics of the Atlas: a technical note.

The posterior arch of the atlas is usually not considered one of the main stabilizers of the cranio-cervical junction, allowing surgeons to its removal when needed with a relative certainty to preserve the stability of the atlo-axial segment. However, these considerations do not reflect the importance to examine the integrity of the posterior arch in the whole biomechanics of the atlas. Authors like Gebauer and Panjabi revealed, respectively in experimental and clinical conditions, how the atlas responds to an axial loading force, proving that the whole atlas is involved into horizontal conversion of axial forces and providing evidence supporting the preservation of the posterior arch. Other authors evaluated the risk for anterior arch fracture following C1 laminectomy. In this technical note three different techniques of posterior atlas arch reconstruction after surgical iatrogenic disruption are presented, considering both neoplastic and degenerative disease.

Three-Dimensional Patient-Matched Template Guides Are Able to Increase Mean Diameter and Length and to Improve Accuracy of Cortical Bone Trajectory Screws: A 5-Year International Experience.

OBJECTIVE: To analyze whether significant differences exist between free-hand three-dimensional (3D) planning-guided cortical bone trajectory (CBT) screw placement and 3D-printed template-guided CBT screw positioning in terms of accuracy, size of screws, and potential complications. METHODS: In this retrospective study, data of adult patients in whom CBT screws were placed for lumbar degenerative pathologies were extracted from a prospectively collected database and analyzed. Patients in whom screws were placed using free-hand 3D planning-guided technique were compared with patients in whom screws were positioned using customized 3D-printed templates. Size of the screws, accuracy, clinical outcomes, and complications were analyzed. RESULTS: The study evaluated 251 patients (1004 screws). The free-hand 3D planning-guided group included 158 patients (632 screws), and the 3D-printed template-guided group included 93 patients (372 screws). The 3D-printed template-guided group involved screws of larger size from L3 to S1. Differences between the 2 groups in terms of accuracy parameters reached statistical significance (P ≤ 0.05). CONCLUSIONS: With the use of 3D patient-matched template guides, mean diameter and length of CBT screws could be safely increased due to improved accuracy of screw placement. Based on previous evidence regarding CBT biomechanical properties, these advantages could allow increased fixation strength over traditional convergent pedicle screw trajectories. Further biomechanics studies are needed.

3D-printed guides for cervical pedicle screw placement in primary spine tumor: Case report and technical description.

Introduction: For spine surgeons, dealing with unstable cervical spine has been usually challenging, and this becomes more difficult when facing a primary craniovertebral junction tumor. Primary spine tumor surgery should always include column reconstruction in order to guarantee biomechanical stability of the spine, but surgeons should always be aware that instrumentations could create interferences with postoperative radiations. However, although carbon fiber instrumentations have started to be used in thoracolumbar oncology for few years, these options are still not available for cervical spine. In the reported case, the adopted strategy to obtain adequate column reconstruction was based on the idea of reducing the amount of titanium needed for posterior fixation and maximizing the distance between the radiation target and titanium rods. Case report and aim: We present the case of a 53-year-old woman harboring a craniovertebral junction chordoma. A short occipito-C3 construct was selected. Specifically, titanium cervical pedicle screws were placed by using a new technology consisting in patient-tailored and customized 3D-printed guides. The aim of this case report is to determine the feasibility and safety of 3D-printed guides for cervical pedicle screw (CPS) positioning, even in the case of cervical spine tumor. Conclusion: CPS could represent a good solution by providing strong biomechanical purchase and tailored 3D-printed guides could increase the safety and the accuracy of this challenging screw placement, even in oncological patients.

Intraoperative Computed Tomography for C1-C2 Stabilization by Goel-Harms: Analysis of Clinical Efficacy and a Novel Classification of Screw Placement Accuracy.

BACKGROUND: The introduction of intraoperative computed tomography (iCT) could improve the surgical results of C1-C2 stabilization by Goel-Harms, especially in patients with complex deformities. This study aims to investigate the impact of iCT on the accuracy of C1-C2 screw positioning and to develop a score based on multiparametric analysis of imaging data (Cervical Screw Placement Accuracy score [CSPAs]). METHODS: Twenty-one patients were retrospectively evaluated. The data obtained with the use of an iCT were compared with the incidence of cases of malpositioning in the literature. Multiparametric imaging criteria were developed: the 82 screw positions were evaluated using the CSPA criteria and 2 additional variables. The CSPAs was obtained from the aggregation of the CSPAs criteria: optimal (CSPAs ≥8), suboptimal (CSPAs = 6-7), malpositioned (CSPAs ≤5). RESULTS: The average incidence of malpositioning in C1-C2 arthrodesis decreased from 13% without iCT to 1.2% with the aid of iCT, considering a monoparametric value. The CSPAs analysis shows a greater discretion and higher number of well-defined categories of the accuracy of C1-C2 screw position: optimal, 80.3%; suboptimal, 17.1%; and malposition, 2.6%. A correlation was observed between the accuracy of the positioning of both right and left screws in C2. Furthermore, the anatomic site of C2 screws was found to be a predictor of cortical invasion. CONCLUSIONS: The results suggest that the introduction of the iCT is associated with a consistent improvement of the accuracy in the positioning of the screws. A multiparametric score (CSPAs) could improve the assessment of screw placement.

Augmented Reality in Medical Practice: From Spine Surgery to Remote Assistance.

Background: While performing surgeries in the OR, surgeons and assistants often need to access several information regarding surgical planning and/or procedures related to the surgery itself, or the accessory equipment to perform certain operations. The accessibility of this information often relies on the physical presence of technical and medical specialists in the OR, which is increasingly difficult due to the number of limitations imposed by the COVID emergency to avoid overcrowded environments or external personnel. Here, we analyze several scenarios where we equipped OR personnel with augmented reality (AR) glasses, allowing a remote specialist to guide OR operations through voice and ad-hoc visuals, superimposed to the field of view of the operator wearing them. Methods: This study is a preliminary case series of prospective collected data about the use of AR-assistance in spine surgery from January to July 2020. The technology has been used on a cohort of 12 patients affected by degenerative lumbar spine disease with lumbar sciatica co-morbidities. Surgeons and OR specialists were equipped with AR devices, customized with P2P videoconference commercial apps, or customized holographic apps. The devices were tested during surgeries for lumbar arthrodesis in a multicenter experience involving author's Institutions. Findings: A total number of 12 lumbar arthrodesis have been performed while using the described AR technology, with application spanning from telementoring (3), teaching (2), surgical planning superimposition and interaction with the hologram using a custom application for Microsoft hololens (1). Surgeons wearing the AR goggles reported a positive feedback as for the ergonomy, wearability and comfort during the procedure; being able to visualize a 3D reconstruction during surgery was perceived as a straightforward benefit, allowing to speed-up procedures, thus limiting post-operational complications. The possibility of remotely interacting with a specialist on the glasses was a potent added value during COVID emergency, due to limited access of non-resident personnel in the OR. Interpretation: By allowing surgeons to overlay digital medical content on actual surroundings, augmented reality surgery can be exploited easily in multiple scenarios by adapting commercially available or custom-made apps to several use cases. The possibility to observe directly the operatory theater through the eyes of the surgeon might be a game-changer, giving the chance to unexperienced surgeons to be virtually at the site of the operation, or allowing a remote experienced operator to guide wisely the unexperienced surgeon during a procedure.

Solitary late spinal metastasis from apocrine salivary duct carcinoma: Case report.

BACKGROUND: The salivary duct carcinomas (SDCs) are rare, high-grade neoplasms involving major salivary glands. Parotid is the most frequently involved gland (85%). Apocrine phenotype (histological presence of decapitation secretions) and androgen reception expression define SDC. The clinical course of these tumors is characterized by aggressive local behavior with extraglandular extension, high recurrence rates, early metastases, and poor prognoses. Despite aggressive surgical/radiation therapy management, the rates of locoregional and metastatic relapses are high, and the mortality rates over 48 months approach 65%. Notably, there is no treatment algorithm available for managing vertebral metastases from apocrine SDC. CASE DESCRIPTION: An elderly male presented with MR/CT findings of an isolated T11 vertebral metastasis attributed to a previously treated parotid SDC. On both CT/MR, it was an osteolytic lesion and demonstrated spinal canal infiltration. The patient underwent surgical biopsy/decompression/resection, following which the lesion histopathologically proved to be a SDC. The patient was subsequently treated with 30 Gy in 10 fractions within 2 weeks of discharge. One-month later, the MRI confirmed adequate epidural decompression without recurrence, and 9 months post-operatively, patient remained disease free. CONCLUSION: Isolated metastasis attributed to parotid SDC followed by radiation therapy may result in tumor control.

Craniovertebral junction chordomas: Case series and strategies to overcome the surgical challenge.

INTRODUCTION: Chordomas are rare and malignant primary bone tumors. Different strategies have been proposed for chordomas involving the craniovertebral junction (CVJ) compared to other locations. The impossibility to achieve en bloc excision, the impact on stability and the need for proper reconstruction make their surgical management challenging. OBJECTIVE: The objective is to discuss surgical strategies in CVJ chordomas operated in a single-center during a 7 years' experience (2013-2019). METHODS: Adult patients with CVJ chordoma were retrospectively analyzed. The clinical, radiological, pathological, and surgical data were discussed. RESULTS: A total number of 8 patients was included (among a total number of 32 patients suffering from skull base chordoma). Seven patients underwent endoscopic endonasal approach (EEA), and posterior instrumentation was needed in three cases. Three explicative cases were reported: EEA for midline tumor involving lower clivus and upper cervical spine (case 1), EEA and complemental posterior approach for occurred occipitocervical instability (case 2), C2 chordoma which required aggressive bone removal and consequent implant positioning, focusing on surgical planning (timing and type of surgical stages, materials and customization of fixation system) (case 3). CONCLUSION: EEA could represent a safe route to avoid injuries to neurovascular structure in clival locations, while a combined approach could be considered when tumor spreads laterally. Tumor involvement or surgical procedures could give raise to CVJ instability with the need of complementary posterior instrumentation. Thus, a tailored preoperative planning should play a key role, especially when aggressive bone removal and implant positioning are needed.

Comorbidity of Cervical Spondylogenic Myelopathy and Amyotrophic Lateral Sclerosis: When Electromyography Makes the Difference in Diagnosis.

Cervical spondylogenic myelopathy (CSM) represents a common differential diagnosis for spinal onset Amyotrophic Lateral Sclerosis (ALS). Identifying occurrence of ALS in patients with CSM may be challenging. We evaluated the accuracy of Awaji criteria in the diagnosis of ALS in a cohort of patients with CSM. We screened all patients attending Turin ALS Center during the 2006-2018 period. We selected only patients for whom cervical cord MRI showed radiological signs of CSM. All patients underwent electromyography (EMG), and Awaji criteria were used for diagnosis of clinically probable ALS. All patients were followed up clinically for at least 6 months, and ALS diagnosis was eventually confirmed according to El-Escorial revised criteria, based on disease progression. Of 2,059 patients screened, in 42 cases, MRI showed signs of CSM; CSM incidence and prevalence risks were 0.16 and 2.04%, respectively. Based on clinical progression, 72.7% of patients were diagnosed as CSM and 27.3% as CSM + ALS. At EMG 6 (18.2%) patients fulfilled the criteria for ALS, 5 of them (83.3%) during clinical follow-up were diagnosed as clinical definite ALS + CSM. Accuracy of Awaji criteria in diagnosing ALS was good (AUC = 0.757, p = 0.03). Sensitivity and specificity of Awaji criteria were, respectively, 55.6 and 95.8%. Positive predictive value was 83.3%, while negative predictive value was 85.2%. CSM-ALS comorbidity is a relatively common problem in clinical practice. To better choose patients who could benefit from surgery, EMG should be performed in CSM patients, due to its good accuracy in recognizing ALS.

Separation surgery for metastatic epidural spinal cord compression: A qualitative review.

INTRODUCTION: The new concept of separation surgery has changed the surgical paradigms for the treatment of metastatic epidural spinal cord compression (MESCC), shifting from aggressive cytoreductive surgery towards less invasive surgery with the aim to achieve circumferential separation of the spinal cord and create a safe target for high dose Stereotactic Body Radiation Therapy (SBRT), which turned out to be the real game-changer for disease's local control. DISCUSSION: In this review a qualitative analysis of the English literature has been performed according to the rating of evidence, with the aim to underline the increasingly role of the concept of separation surgery in MESCC treatment. A review of the main steps in the evolution of both radiotherapy and surgery fields have been described, highlighting the important results deriving from their integration. CONCLUSION: Compared with more aggressive surgical approaches, the concept of separation surgery together with the advancements of radiotherapy and the use of SBRT for the treatment of MESCC showed promising results in order to achieve a valuable local control while reducing surgical related morbidities and complications.

A Tailored Approach to Cortical Bone Track for Spine Fixation Surgery: 3-Dimensional Printed Custom Made Guides for Screws Placement: 2-Dimensional Operative Video.

Cortical bone trajectory (CBT) screw fixation is an attractive technique.1-4 However, the ideal insertion of those screws could be technically demanding.5,6 The use of 3-dimensional (3D) patient-matched guides increase safety for CBT screws implantation.7 In this video, the case of a 46 yr old male is presented. He complained low back pain with left sciatica. magnetic resonance imaging showed an L5/S1 degenerative disc disease with left herniation. The patient was positioned prone; the L5 spinous process was identified under fluoroscopic guidance than skin incision was performed. Preserving the cranial facet joints, spinous processes and laminae of L5 and S1 vertebrae were exposed. Guides were positioned on the corresponding vertebra and the contact areas checked to avoid any discrepancy. With a high-speed drill the cortical bone was violated through the guide tubes. The drill itself has a stop mechanism provided by the guides. With this mechanism the drilling can be safely performed up to the planned depth. Guidewires were than introduced into the pedicle and body of the vertebra; undertapping could be performed with cannulated instrument. Laminectomy and facetectomy were performed. Diskectomy was performed, then a titanium kidney-shaped pivoting cage was implanted. Four Screws were finally placed. Proper positioning of the implants were verified on fluoroscopy and on the postoperative computed tomography scan confirming the accuracy of the trajectory. All procedures performed for this study were in accordance with the ethical standards of our Institute and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. Written informed consent was obtained from the patient who is operated in this video.

The Neurology-Stability-Epidural compression assessment: A new score to establish the need for surgery in spinal metastases.

OBJECTIVE: The aim of this study was to translate new evidence about management of spinal metastases in a practical and reliable score for surgeons, radiation oncologists and oncologists, able to establish the need for surgery regardless the available technology and settings. PATIENTS AND METHODS: Three main items were identified and graded: Neurological status (0-5 points), Stability of the spine according to the Spinal Instability Neoplastic Score (SINS) Score (0-5 points), and Epidural compression according to the Epidural Spinal Cord Compression (ESCC) scale (0-3 points). Patients were considered suitable for surgery with ASA score < 4 and ECOG score <3. A retrospective clinical validation of the NSE score was made on 145 patients that underwent surgical or non surgical treatment. RESULTS: Agreement between the undertaken treatment and the score (88.3% of patients), resulted in a strong association with improvement or preservation of clinical status (neurological functions and mechanical pain) (p < 0.001) at 3 and 6 months. In the non-agreement group no association was recorded at the 3 and 6 months follow-up (p 0.486 and 0.343 for neurological functions, 0.063 and 0.858 for mechanical pain). CONCLUSION: Functional outcomes of the study group showed that the proposed NSE score could represent a practical and reliable tool to establish the need for surgery. Agreement between the score and the performed treatments resulted in better clinical outcomes, when compared with patients without agreement. Further validation is needed with a larger number of patients and to assess reproducibility among surgeons, radiation oncologists, and oncologists.

Cortical bone trajectory technique's outcomes and procedures for posterior lumbar fusion: A retrospective study.

Cortical Bone Trajectory screws allow a limited soft tissue dissection with mechanical properties comparable to traditional pedicle screws. However, clinical results are still reported on limited samples. The study aimed to evaluate perioperative and mid-term follow up outcomes, clinical results and complications in 238 consecutive patients underwent CBT fusion for degenerative lumbosacral disease. Pre- and intraoperative data, clinical outcomes and complications were collected. The patients were stratified in three groups. The original technique was performed in the first 43 cases without a preoperative CT scan planning. The second group includes the patients who underwent preoperative CT scan for entry point and screw trajectory planning (158 patients). Surgical procedures in the last group were performed with patient-matched 3D printed guide (37 patients). The accuracy in screws positioning was evaluated on postoperative CT scan. The mean follow-up was 32.3 months. Mean ODI and VAS index improved with statistical significance. Mean procedural time was 187, 142 and 124 min in the three subgroups. The total amount of recorded complications was 4.2% (16.3%, 3.8% and 0.0% respectively). Screws entirely within the cortex of the pedicle were 78.9%, 90.5% and 93.9% in the three groups. Fusion was obtained in 92.4% of cases. The CBT technique is a safe procedure, especially with an accurate preoperative CT scan-based planning. This seems more evident with the 3D template patient-matched guide. More studies are needed to directly compare traditional pedicle screws and CBT screws on long-term outcomes.

Carbon fiber reinforced vs titanium implants for fixation in spinal metastases: A comparative clinical study about safety and effectiveness of the new "carbon-strategy".

In spinal oncology traditional titanium implants could significantly impair evaluation of postoperative imaging because of artifacts, potentially affecting proper planning and execution of radiotherapy and adequate radiological follow-up to rule out progression of the disease. This is why carbon fiber reinforced (CFR)-PEEK implants have been developed for spinal fixation. The advantages of this system include fewer artifacts on imaging, potentially improving the execution and quality of radiotherapy, with also a reduced scattering effect to neighboring tissues. A comparative clinical and radiological study between new CFR-PEEK and standard titanium implants is described. Data recorded for each case included patient demographics, clinical, radiological and surgical data, intra- and postoperative complications, follow-up information. The goal of this study was to verify the safety and effectiveness of CFR-PEEK devices compared to standard titanium implants. A total number of 78 patients were reviewed. 36 patients underwent CFR-PEEK fixation, while titanium implants were used for 42 patients. Functional recovery was obtained in both groups and registered at last follow-up in terms of axial pain and neurological status. No significative differences were found between the two groups in terms of post-operative clinical complications and hardware-related complications. CFR-PEEK implants constitute a feasible and effective way to restore stability in metastatic spine tumors. This study found a non inferior favorable profile in terms of intraoperative and postoperative complications and functional recovery, compared to titanium. Further prospective studies are needed to clarify the potential oncological advantage of their radiolucency.

The Era of Cortical Bone Trajectory Screws in Spine Surgery: A Qualitative Review with Rating of Evidence.

The use of cortical bone trajectory (CBT) pedicle screws for posterior fixation and fusion seems to constitute a viable alternative for spinal procedures, with the potential to mitigate risks, be minimally invasive, and cause less tissue damage than the traditional technique. This review analyzes the literature regarding CBT according to the rate of evidence of articles and their main focus. CBT has proved to be a safe and viable option for screw fixation in spine surgery. Given the denser bone interception, high-quality biomechanics studies show equal or even better properties compared with classic pedicle screw fixation, depending on several factors such as screw size and length. Through the years, surgical technique has improved to gain a longer and safer trajectory than first described. Level 2 and 3 clinical studies suggest equal clinical and radiologic outcomes compared with pedicle trajectory fixation, but high-quality, level 1, randomized controlled trials are needed to confirm these results.