Computed Tomography Navigation Research Articles

Computed tomography and structured light imaging guided orthopedic navigation puncture system: effective reduction of intraoperative image drift and mismatch

BackgroundImage-guided surgical navigation systems are widely regarded as the benchmark for computer-assisted surgical robotic platforms, yet a persistent challenge remains in addressing intraoperative image drift and mismatch. It can significantly impact the accuracy and precision of surgical procedures. Therefore, further research and development are necessary to mitigate this issue and enhance the overall performance of these advanced surgical platforms.ObjectiveThe primary objective is to improve the precision of image guided puncture navigation systems by developing a computed tomography (CT) and structured light imaging (SLI) based navigation system. Furthermore, we also aim to quantifying and visualize intraoperative image drift and mismatch in real time and provide feedback to surgeons, ensuring that surgical procedures are executed with accuracy and reliability.MethodsA CT-SLI guided orthopedic navigation puncture system was developed. Polymer bandages are employed to pressurize, plasticize, immobilize and toughen the surface of a specimen for surgical operations. Preoperative CT images of the specimen are acquired, a 3D navigation map is reconstructed and a puncture path planned accordingly. During surgery, an SLI module captures and reconstructs the 3D surfaces of both the specimen and a guiding tube for the puncture needle. The SLI reconstructed 3D surface of the specimen is matched to the CT navigation map via two-step point cloud registrations, while the SLI reconstructed 3D surface of the guiding tube is fitted by a cylindrical model, which is in turn aligned with the planned puncture path. The proposed system has been tested and evaluated using 20 formalin-soaked lower limb cadaver specimens preserved at a local hospital.ResultsThe proposed method achieved image registration RMS errors of 0.576 ± 0.146 mm and 0.407 ± 0.234 mm between preoperative CT and intraoperative SLI surface models and between preoperative and postoperative CT surface models. In addition, preoperative and postoperative specimen surface and skeletal drifts were 0.033 ± 0.272 mm and 0.235 ± 0.197 mm respectively.ConclusionThe results indicate that the proposed method is effective in reducing intraoperative image drift and mismatch. The system also visualizes intraoperative image drift and mismatch, and provides real time visual feedback to surgeons.

Robotic-Assisted Navigation in Single-Level Transforaminal Lumbar Interbody Fusion Reduces Surgeons’ Mental Workload Compared With Fluoroscopic and Computed Tomographic Techniques: A Nonrandomized Prospective Controlled Trial

Background: Pedicle screw placement during spine fusion is physically and mentally demanding for surgeons. Consequently, spine surgeons can become fatigued, which has implications for both patient safety and surgeon well-being. Purpose: We sought to assess the cognitive workload of surgeons placing pedicle screws using robotic-assisted navigation compared with fluoroscopic and computed tomography (CT)-assisted placement. Methods: We performed a nonrandomized prospective controlled trial to compare the cognitive workload of 3 surgeons performing single-level minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) using robotic, CT, or fluoroscopic navigation on 25 patients (15 in the robotic navigation group and 10 in the nonrobotic group). Immediately after each procedure, surgeons submitted the National Aeronautics and Space Administration–Task Load Index (NASA-TLX), which has 6 subscales: mental demands, physical demands, temporal demands, performance, effort, and frustration. Four tasks associated with pedicle screw placement were assessed independently: (1) screw planning, (2) calibrating robot/obtaining imaging/registration, (3) pedicle cannulation, and (4) screw placement. Patient demographics and surgical characteristics were obtained and reviewed. Results: Surgeons’ self-reported cognitive workload was significantly reduced when using robotic-assisted navigation versus CT/fluoroscopic navigation. Workload was reduced for screw planning, pedicle cannulation, and screw placement. In addition, there were significant reductions in each subdomain for these 3 tasks, encompassing mental demand, physical demand, temporal demand, effort, and frustration with improved task performance. Conclusions: This study found significant reductions in mental workload with improved perceived performance for robotic-assisted pedicle screw placement compared with fluoroscopic and CT-navigation techniques. Lowering the cognitive burden associated with screw placement may allow surgeons to address the remainder of the operative case with less decision fatigue, prevent complications, and increase surgeon wellness.

Computed tomography navigation radiofrequency ablation for Meige's syndrome: A game-changer in treatment

BackgroundMeige's syndrome severely impacts quality of life. Current treatments struggle to balance cost, risk, and effectiveness. MethodsPatients with blepharospasm were treated with facial nerves partial radiofrequency ablation guided by CT. Treatment efficacy, complications, and recurrences were evaluated during follow-up. Results116 facial nerves in 58 patients with Meige's syndrome were treated using CT guidance. The average temperature at the end of radiofrequency treatment was 77.93 ± 9.8 °C, and the procedure lasted an average of 30.79 ± 7.69 min. Spasms stopped after treatment, but mild facial paralysis remained. Follow-ups ranging from 12 to 57 months showed that facial paralysis improved in an average of 3.12 ± 0.94 months. Nine patients had unilateral recurrence within 6–13 months, and three had bilateral recurrence at 14, 18, and 22 months. ConclusionsPartial radiofrequency ablation of the facial nerve through percutaneous access to the bilateral stylomastoid foramen using CT navigation is an effective, safe, promising treatment for blepharospasm in Meige's syndrome patients.

Placement of 2 cages using navigation-guided biportal endoscopic transforaminal lumbar interbody fusion: illustrative case.

In recent developments, full endoscopic and unilateral biportal endoscopic (UBE) spine surgery have emerged to aid the transforaminal lumbar interbody fusion (TLIF) procedure. Yet, both approaches present a challenge due to limited space for cage insertion, potentially leading to complications such as cage subsidence or nonfusion in long-term assessments. Utilizing double cages may mitigate these concerns. This paper presents a unique case in which a patient successfully underwent computed tomography (CT) navigation-guided UBE-TLIF with 2 converging cages, highlighting the potential benefits and feasibility of this innovative approach. A 59-year-old female diagnosed with degenerative spondylolisthesis at the L4-5 level underwent a UBE-TLIF. The operation is detailed step by step and supported by illustrative figures and surgical videos. Postsurgery results revealed a significant improvement in the patient's condition, with the visual analog scale score decreasing from 7 to 3 on the first day, leading to a satisfaction rate of 90% at the last follow-up. Utilizing endoscopic visualization complemented by contrast medium has substantially elevated the quality of disc preparation. From their observations, the authors affirm that the integration of intraoperative CT navigation systems significantly augments safety and pinpoint accuracy in UBE-TLIF procedures. The strategy of employing 2 converging cages through a unilateral technique stands as a practical solution, potentially optimizing the fusion outcomes of UBE-TLIF surgery. https://thejns.org/doi/10.3171/CASE23512.

Comparative analysis of 'functional excision' of heterotopic ossification around the hip - computed tomography (CT) navigation guided versus conventional excision.

We aim to analyse and compare the efficacy of the excision of HO around the hip with and without CT-guided navigation. We also aim to compare the functional outcome between CT navigation guided versus conventional excision of HO. This study is a retrospective analysis of prospectively collected data from 2015 to 2022. There were 23 patients (24 hips) in the final cohort. Intraoperative CT navigation guided excision was performed in 7 hips and conventional excision of HO was done in 17 hips. The HO was classified by Brooker's grading in radiographs. CT scan was taken preoperatively in all patients to exactly identify the volume, location and preoperative planning. The functional outcome was analysed according to Harris Hip Score (HHS) and International Hip Outcome Tool (iHOT) for self-ambulatory patients and improvement in the sitting or nursing care was assessed in patients mobilising with wheelchair or walker support. Any complications or recurrence noted postoperatively and in follow-up were recorded. The mean follow-up was 41.2 months in the CT navigation-guided excision group and 55 months in the conventional excision group. According to Brooker's grading, grade IV was present in 20 hips and grade III in four hips. Twelve patients were self-ambulatory and the other 12 patients were requiring support for mobilisation. There was a significant improvement in the HHS from 21.3 ± 3.7, 18.3 ± 2.5 preoperatively to 75.2 ± 8.3, 72.2 ± 4.3 postoperatively in the CT navigation guided and conventional group respectively (p < 0.001) in the self-ambulatory group. There was one anterior wall and one partial posterior wall fracture in the conventional group. One patient in the conventional group had a deep infection and recurrence. One patient had a superficial infection and another had superficial vein thrombosis in the CT guided excision group. Intraoperative CT navigation helps to exactly localize the HO and facilitates safe excision. Functional excision of the HO leads to better nursing care and functional outcomes between both groups.

Diagnostic Efficacy of Trephine Biopsy and Core Biopsy of Bone and Soft Tissue Tumors

Verification of pathomorphological diagnosis is a key stage in selection of treatment tactics in patients with neoplasms. Understanding of the nature of pathological process is especially important in context of primary tumors of the bones, soft tissues and metastases as despite active development of diagnostic techniques, they do not allow to obtain full information on histological nature of the tissues, differentiation grade, as well as molecular and genetic characteristics of the tumor. These data are associated with selection of optimal treatment tactics at every stage and disease prognosis. The optimal approach to obtaining histological materials in tumor of the bones and soft tissues are radiologically guided (X-ray, computed tomography and magnetic resonance imaging) trephine biopsy or ultra-sound-guided core biopsy.Aim. To determine information value of trephine and core biopsies of neoplasms of the bones and soft tissues of various locations, identify mistakes during manipulation affecting results of morphological diagnosis.Materials and methods. Between 2015 and 2023 at the Russian Scientific Center of Roentgenoradiology, 788 patients aged 18–85 years (380 men, 408 women) underwent 602 trephine biopsies and 248 core biopsies (n = 850) of neo-plasms of the soft tissues and bones of various locations. Absence of informational value of morphological study required repeat trephine biopsies in 19 patients, core biopsies in 2 patients, open biopsies in 13 patients.Results. Informational value of trephine biopsy of the bones was 90.5 % (long bones – 96.8 %, flat bones – 91.6 %, spine bones – 82.1 %), core biopsy of the soft tissues 98.8 %. Sufficient amount of material for immunohistochemical testing was obtained in 89 % biopsies. Interventions in cases of bone neoplasms were performed using CT (computed tomography) navigation; for core biopsies of the soft tissues, ultrasound was used. Absence of informational value in trephine bio psies was caused by insufficient amount of material (48 (7.97 %) cases), retrieval of trephine biopsy from the area of tumor necrosis (4 (0.67 %) cases), incorrect selection of access (4 (0.67 %) cases) and needle type (1 (0.17 %) case).Conclusion. Results of analysis of trephine and core biopsy data of bone and soft tissue neoplasms showed high information value, which is supported by literature data. This allows to consider these methods of histological material retrieval the “golden standard” of bone and soft tissue tumor diagnosis.

Placement of ilio-sacral screws in fusionless technique for pediatric neuromuscular scoliosis utilizing planning software, in conjunction with intraoperative navigation, results in a safer optimal screw: a CT-based study.

The insertion of ilio-sacral (IS) screws for distal anchoring in the instrumentation of pediatric neuromuscular scoliosis (NS) presents a significant challenge, often leading to elevated rates of complications. Utilizing computed tomography (CT) navigation and preoperative planning technology is proposed as a potential solution to mitigate these challenges. This study aims to assess the precision of IS screw placement through CT-graphic measurements, both with and without preoperative planning, followed by navigated IS screw insertion, in pediatric neuromuscular scoliosis. Thirty-two treated patients were grouped based on surgical procedure: planned (P): 19 patients (n=38 screws) and non-planned (NP): 13 patients (n=26 screws). All screw placements (P and NP) took place under CT navigation. IS screw trajectories of P-group were drawn preoperatively on CT images with the cranial trajectory planning program and fused with the intraoperative CT images. There are several important anatomical structures that should be avoided when placing the IS screw (L5 root, spinal canal, L5S1 facet, SI joint, neurovascular structures anteriorly to the sacrum, S1 root in the S1 foramen and the intestines). Each trajectory was evaluated based on seven radiographical parameters whom we have enlisted partially based on the essentials of a good trajectory described by Miladi et al. (1: Ilium; 2: SI joint; 3: Promontorium; 4: Sacral plate; 5: Anterior sacral cortex; 6: S1 foramen; 7: Spinal canal). An independent sample T test was executed to compare both groups. The trajectories in the P group showed a significantly (P<0.05) higher overall similarity and optimality (12.1±2.1 vs 9.1±2.2 points) compared to the non-planned trajectory. Preoperative planning and navigated placement of IS screws on fusion images with intraoperative CT, results in a better trajectory of the ilio-sacral screws.

Characteristics of Screw Perforation and Screw Loosening in Atlantoaxial Transarticular Fixation Using a Preoperative Computed Tomography-Based Navigation System.

Atlantoaxial transarticular fixation, also called the Magerl technique, is said to be the most robust biomechanical method of fixation of the atlantoaxial vertebrae. However, the procedure carries a risk of spinal cord and vertebral artery injury during the insertion process, especially in patients with a high-riding vertebral artery. In this study, a computed tomography (CT)-based navigation system was used for preoperative planning and insertion. This investigation sought to determine the rate and direction of screw perforation as well as the incidence of screw loosening in computer-assisted atlantoaxial transarticular fixation. Sixty patients (31 men and 29 women; mean ± SD age: 65.3 ± 19.6 years) who received atlantoaxial transarticular screw insertion with preoperative CT navigation were analyzed. We investigated screw position and loosening by CT at the final follow-up. Of the 108 screws inserted, the rate of Grade 2 or higher perforation was 4.6% (5/108). Nine of 81 (11.1%) screws inserted into the 44 patients who were followed for at least 6 months showed loosening. Logistic regression analysis revealed that unilateral insertion (odds ratio: 8.50, 95% confidence interval: 1.53-47.2, P = 0.014) was significantly associated with the incidence of screw loosening. The screw perforation rate of Grade 2 or higher in computer-assisted atlantoaxial transarticular screw fixation was 4.6%, with comparable frequencies of perforation direction. Unilateral insertion was a significant independent factor associated with screw loosening, which occurred in 11.1% of insertions. Spine surgeons should follow up with patients with caution because screws with unilateral insertion are prone to loosening.

Advancements in pelvic ring fracture surgery: Assessing INFIX screw placement accuracy with CT navigation

The management of unstable pelvic ring fractures, typically resulting from high-energy trauma, presents a significant clinical challenge due to the complexity of injuries. While effective in many cases, the traditional stabilization methods are fraught with various complications that can significantly impact patient recovery and quality of life (QOL). This study aims to evaluate the efficacy and precision of the anterior subcutaneous internal fixator (INFIX) technique when used with intraoperative computed tomography (CT) navigation, a novel approach intended to mitigate the limitations of conventional treatment modalities.Our retrospective case series encompasses 43 patients who sustained traumatic pelvic injuries and were subsequently treated with the INFIX technique from December 2020 to January 2024. The focus of this analysis was to assess the accuracy of INFIX screw placement facilitated by intraoperative CT navigation.A total of 81 INFIX screws were inserted, and our study findings reveal a high level of precision in screw placement, with only one screw deviating, resulting in an inaccuracy rate of merely 1.2 %. This highlights the significant advantage provided by intraoperative CT navigation. The high level of accuracy not only enhances the stability of the pelvic fixation but also substantially reduces the risk of complications commonly associated with screw misplacement, such as abdominal damage, vascular injury, and issues related to incorrect hardware positioning.In conclusion, the integration of the INFIX technique with intraoperative CT navigation in the treatment of unstable pelvic ring fractures represents a significant advancement in orthopedic trauma surgery. This study provides compelling evidence supporting the efficacy and precision of this approach, suggesting its potential as a superior alternative to traditional fixation methods. Further research, ideally through prospective studies involving larger patient cohorts, is needed to validate these findings and explore the long-term implications of this technique on patient recovery and QOL.

Single-Stage Lateral Anterior-to-Psoas Interbody Fusion and Facet Screws as a Treatment for L5–S1 Adjacent Segment Disease in a Patient With a Long-Segment Construct

Objective: Adjacent segment disease (ASD) occurs in 9% of patients with long-segment lumbar spine fusion and results from the transmission of a greater degree of stress to the segments cranial and caudal to a fused segment. The treatment of symptomatic ASD typically involves extending fusion to the involved segment. Revision and extension of posterior instrumentation bears the disadvantage of involving the exposure and modification of old hardware. Lateral interbody fusion cannot be performed at L5/S1 due to the iliac crest. Anterior lumbar interbody fusion typically still requires flipping the patient to augment the construct posteriorly. Here, we present a method to treat L5/S1 ASD using single-position anterior-to-psoas (ATP) interbody fusion combined with facet screw instrumentation.Methods: An 80-year-old man, who had undergone L2-5 fusion 27 years ago, presented with persistent lower back pain and gait dysfunction with imaging findings of L5/S1 spondylosis and ASD. Under intraoperative computed tomography navigation, left L5/S1 ATP interbody fusion was performed with simultaneous L5/S1 percutaneous facet screw fixation. Results: The abdominal incision was 4.0 cm and the single posterior incision was 1.5 cm long. Blood loss was lower than 10 mL, and the procedure lasted for less than 1.5 hours. The patient was discharged to rehabilitation after 3 days.Conclusion: ATP interbody fusion enabled the placement of an interbody device with a large footprint to promote fusion and reduce the risk of subsidence and pseudoarthrosis. The combined use of interbody fusion and facet screws obviates the need to link to the previous construct.

Impact of osteosclerosis on cervical pedicle screw insertion using preoperative CT-based navigation.

Preoperative computed tomography (CT)-based navigation is used for cervical pedicle screw (CPS) insertion to mitigate the risk of spinal cord and vertebral artery injury. In vertebrae with osteosclerosis due to degeneration or other factors, however, probing may not proceed easily, with difficulty creating the CPS insertion hole. This study investigated the impact of osteosclerosis on the accuracy of CPS insertion. A total of 138 patients with CPS inserted at the C3-C7 level using preoperative CT navigation were retrospectively analyzed. Pre- and postoperative CT was employed to investigate screw position and Hounsfield unit (HU) values at the lateral mass to evaluate the degree of osteosclerosis in the CPS insertion pathway. Among 561 CPS insertions, the Grade 3 perforation rate was 1.8%, and the Grade 2 or higher perforation rate was 8.0%. When comparing insertions with and without CPS perforation, HU values were significantly higher in the perforation group (578 ± 191 vs. 318 ± 191, p < 0.01). The frequency of CPS insertion into the mid-cervical spine was also significantly greater in the perforation group (68.9% vs. 62.5%, p < 0.01). Logistic regression analysis revealed that a high HU value at the lateral mass (odds ratio 1.09, 95% confidence interval: 1.07-1.11, p < 0.01) was a significant independent factor associated with CPS deviation. The screw perforation rate of Grade 2 or higher in CPS insertion using preoperative CT-based navigation was 8.0%. Since osteosclerosis was an independent factor related to CPS deviation, additional care may be required during insertion into affected vertebrae.

A Novel Intraoperative CT Navigation System for Spinal Fusion Surgery in Lumbar Degenerative Disease: Accuracy and Safety of Pedicle Screw Placement.

Background: In recent years, intraoperative computed tomography (CT) navigation has become widely used for the insertion of pedicle screws in spinal fusion surgery. However, conventional intraoperative CT navigation may be impaired by infrared interference between the infrared camera and surgical instruments, which can lead to the misplacement of pedicle screws. Recently, a novel intraoperative CT navigation system, NextAR, has been developed. It uses a small infrared camera mounted on surgical instruments within the surgical field. NextAR navigation can minimize the problem of infrared interference and be expected to improve the accuracy of pedicle screw placement. Methods: This study investigated the accuracy of pedicle screw insertion under NextAR navigation in spinal fusion surgery for lumbar degenerative diseases. The accuracy of pedicle screw placement was evaluated in 15 consecutive patients using a CT grading scale. Results: Screw perforation occurred in only 1 of the total 70 screws (1.4%). Specifically, there was one grade 1 perforation within 2 mm, but no perforations larger than 2 mm. There were no reoperations or neurological complications due to screw misplacement. Conclusions: NextAR navigation can provide high accuracy for pedicle screw insertion and help ensure safe spinal fusion surgery for lumbar degenerative diseases.

Functional and Radiological Outcomes of All-Posterior Surgical Correction of Dystrophic Curves in Patients with Neurofibromatosis Type 1.

A retrospective cohort study. To determine outcomes following all-posterior surgery using computed tomography navigation, hybrid stabilization, and multiple anchor point techniques in patients with neurofibromatosis type 1 (NF-1) and dystrophic scoliosis. Previous studies favored antero-posterior fusion as the most reliable method; however, approaching the spine anteriorly was fraught with significant complications. With the advent of computer assisted navigation and multiple anchor point method, posterior only approach is reporting successful outcomes. This study included patients who underwent all-posterior surgical deformity correction for dystrophic NF-1 curves. Coronal and sagittal Cobbs angles, apical rotation, and the presence of dystrophic features were evaluated before surgery. Postoperatively, sagittal, coronal, and axial correction, implant position, and implant densities were evaluated. The decline in curve correction and implant-related complications were evaluated at follow-up. Clinical outcomes were evaluated using the Scoliosis Research Society-22 revised index. This study involved 50 patients with a mean age of 13.6 years and a mean follow-up duration of 5.52 years. With a mean coronal flexibility of 18.7%, the mean apical vertebral rotation (AVR), preoperative coronal Cobb angle, and sagittal kyphosis were 27.4°, 64.01°, and 47.70°, respectively. The postoperative mean coronal Cobb angle was 30.17° (p <0.05), and the sagittal kyphosis angle was 25.4° (p <0.05). The average AVR correction rate was 41.3%. The correction remained significant at the final mean follow-up, with a coronal Cobb angle of 34.14° and sagittal kyphosis of 25.02° (p <0.05). The average implant density was 1.41, with 46% of patients having a high implant density (HID). The HID had a markedly higher mean curve correction (29.30° vs. 38.05°, p <0.05) and a lower mean loss of correction (5.7° vs. 3.8°, p <0.05). Utilizing computer-assisted navigation, hybrid instrumentation, and multiple anchor point technique and attaining high implant densities, this study demonstrates successful outcomes following posterior-only surgical correction of dystrophic scoliosis in patients with NF-1.

[Translated article] Insertion of S1 iliosacral screws in the computed tomography room: An alternative to improve safety in the percutaneous management of posterior pelvic ring injuries

IntroductionThe main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation. MethodologyRetrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results. ResultsForty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed. ConclusionWe advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

An Overview of Recent Advances in Anterior Cervical Decompression and Fusion Surgery.

Anterior cervical diskectomy and fusion (ACDF) has evolved significantly in the last few years with the aim of enhancing effectiveness and safety while reducing hospitalization and healthcare-related costs. Transitioning from iliac crest autografts to allografts minimizes donor-site complications like pain, infections, and hematoma. Allograft options, such as polyetheretherketone (PEEK) and tantalum, vary in their osteoinductive properties and elastic modulus, influencing fusion rates, time, and the rate of subsidence. Recently introduced zero-profile cages offer bone fixation through screws, resulting in reduced blood loss, improved spinal alignment, and decreased complications like dysphagia and adjacent segment disease. Intraoperative neuromonitoring (IONM) has gained widespread use. The North American Spine Society (NASS) 2023 recommendations endorse IONM in cervical deformity corrections and myelopathy cases. Insufficient studies hinder clear radiculopathy recommendations, but emerging research supports IONM for patients at greater risk of C5 nerve root injury or positional injury. Advancements in hemostatic agents, such as gelatin sponges, oxidized cellulose, and fibrin sealants, contribute to safety by reducing postoperative hematoma rates and eliminating the need for drainage. Innovations like the exoscope, endoscope, and computed-tomography (CT) navigation have transformed surgical practices. Exoscopes are emerging as an alternative to microscopes, offering benefits like a smaller footprint, adjustable positioning, lower costs, and shared intraoperative views for educational purposes. The use of endoscope offers the possibility of performing a minimally invasive technique with improved results in terms of cosmesis and patient-perceived outcome. CT navigation can be useful in high-risk procedures, such as cervical plate placement for major instability. This paper provides an overview of cutting-edge technologies in ACDF surgery, emphasizing cage materials and designs, safety measures, and operating room advancements. It also highlights areas for future research, underlining the procedure's continuous evolution.

Assessing Procedural Accuracy in Lateral Spine Surgery: A Retrospective Analysis of Percutaneous Pedicle Screw Placement with Intraoperative CT Navigation.

Percutaneous pedicle screws (PPSs) are commonly used in posterior spinal fusion to treat spine conditions such as trauma, tumors, and degenerative diseases. Precise PPS placement is essential in preventing neurological complications and improving patient outcomes. Recent studies have suggested that intraoperative computed tomography (CT) navigation can reduce the dependence on extensive surgical expertise for achieving accurate PPS placement. However, more comprehensive documentation is needed regarding the procedural accuracy of lateral spine surgery (LSS). In this retrospective study, we investigated patients who underwent posterior instrumentation with PPSs in the thoracic to lumbar spine, utilizing an intraoperative CT navigation system, between April 2019 and September 2023. The system's methodology involved real-time CT-based guidance during PPS placement, ensuring precision. Our study included 170 patients (151 undergoing LLIF procedures and 19 trauma patients), resulting in 836 PPS placements. The overall PPS deviation rate, assessed using the Ravi scale, was 2.5%, with a notably higher incidence of deviations observed in the thoracic spine (7.4%) compared to the lumbar spine (1.9%). Interestingly, we found no statistically significant difference in screw deviation rates between upside and downside PPS placements. Regarding perioperative complications, three patients experienced issues related to intraoperative CT navigation. The observed higher rate of inaccuracies in the thoracic spine suggests that various factors may contribute to these differences in accuracy, including screw size and anatomical variations. Further research is required to refine PPS insertion techniques, particularly in the context of LSS. In conclusion, this retrospective study sheds light on the challenges associated with achieving precise PPS placement in the lateral decubitus position, with a significantly higher deviation rate observed in the thoracic spine compared to the lumbar spine. This study emphasizes the need for ongoing research to improve PPS insertion techniques, leading to enhanced patient outcomes in spine surgery.

Inserción de tornillos iliosacros S1 en la sala de tomografía computarizada. Una alternativa para mejorar la seguridad en el tratamiento percutáneo de las lesiones posteriores del anillo pélvico

IntroductionThe main complication of percutaneous iliosacral screw fixation is implant malposition, which can lead to vascular and nerve damage. The anatomical variability of the sacrum can make screw insertion difficult under fluoroscopic guidance. Among the methods described to improve the accuracy of this technique, stands out the use of computed tomography (CT). The aim of this study is to compare the results of iliosacral screw insertion with fluoroscopy or CT navigation. MethodologyRetrospective cohort study of 66 iliosacral screws in 56 patients during 11 years. The screws were inserted with fluoroscopy in the operating room or with CT in the radiodiagnosis area. We collected data on patient characteristics, lesions, treatment, and clinical and radiological results. ResultsForty-seven screws were inserted with fluoroscopy and 19 with CT. A percentage of 18.2 of screws perforated the S1 osseous corridor. All of them were inserted with fluoroscopy guidance (0 vs. 34%; p<0.01). Those operated with CT accumulated more sacral dysmorphism criteria than those operated with fluoroscopy (2.2 vs. 1.6; p=0.02). The S1 corridor on the axial CT view was narrower in those in whom perforation had occurred (18.8 vs. 21.0mm; p=0.02). Two cases with perforation developed S1 radiculalgia. Two endopelvic screws had to be removed. ConclusionWe advise the use of CT guidance for iliosacral screw insertion in patients with sacral dysmorphism or narrow S1 corridors in facilities where other navigation methods are not available.

Minimally Invasive Approach for Degenerative Spondylolisthesis: Lateral Single-Position Surgery with Intraoperative Computed Tomography Navigation and Fluoroscopy: A Technical Note

Degenerative spondylolisthesis (DS) is a prevalent condition that leads to low back pain and neurological symptoms. This technical note presents a novel surgical strategy for treating DS using lateral single-position surgery (SPS) in combination with intraoperative computed tomography navigation and fluoroscopy. Fifteen patients (5 males and 10 females, mean age 70.2years) diagnosed with DS with a slip of 5mm or more underwent lateral lumbar interbody fusion (LLIF) with percutaneous pedicle screw (PPS) fixation using this technique. The procedure involved slip reduction using an upside PPS and rod fixation, followed by LLIF performed in the same lateral position. The term "upside PPS" refers to a PPS that is inserted on the ceiling side of the patient's surgical field. Preoperative and postoperative radiographic assessments were conducted to evaluate the effectiveness of the lateral SPS. The results demonstrated significant improvements in various parameters, including spondylolisthesis reduction, segmental lordosis, disc height, and spinal canal dimensions. The lateral-SPS procedure exhibited several advantages over traditional flip LLIF approaches for slip reduction. Additionally, the technique provided accurate intraoperative navigation guidance through computed tomography imaging, ensuring precise implant placement and slip reduction. Combining LLIF and PPS fixation in a single procedure presents a precise, efficient approach for DS treatment, minimizing repositioning needs. This technique enables effective lumbar reconstruction, restoration of spinal stability, and improved patient outcomes. Although further investigation is warranted, lateral SPS surgery may hold promise as an innovative solution for managing DS by reducing surgical invasiveness and optimizing surgical efficiency.

Reduction in CT scan number with the reference frame middle attachment method in intraoperative CT navigation for adolescent idiopathic scoliosis.

Elucidate whether it is preferable to use the reference frame (RF) middle attachment (RFMA) method over the edge of the planned pedicle screw (PS) insertion area for RF placement in the surgery for adolescent idiopathic scoliosis (AIS) with intraoperative computed tomography (CT) navigation. Eighty-six consecutive patients (76 female and 10 male; mean age: 15.9years) with AIS who underwent posterior spinal fusion using intraoperative CT navigation were enrolled. The group with the RF placed at the most distal part of the CT scan range was defined as the distal group (Group D), with other placements classified into the middle group (Group M). PS perforation rate and surgical outcome were compared between the groups. There was no significant difference in perforation rate between Group M and Group D (3.4% vs. 3.0%, P = 0.754). The mean ± standard deviation number of instrumented vertebrae at the first CT scan was significantly higher in Group M (8.2 ± 1.2 vs. 6.3 ± 1.2, P < 0.001), while mean blood loss was significantly lower (266 ± 185mL vs. 416 ± 348mL, P = 0.011). The frequency of needing a second CT scan for PS insertion was significantly lower in Group M (38% vs. 69%, P = 0.04). The RFMA method in thoracic scoliosis surgery for AIS with intraoperative CT navigation could significantly decrease the number of CT scans and blood loss while maintaining a comparable PS perforation rate to RF placement at the distal end of the planned PS insertion range.

Modification to the placement of the navigation reference frame in posterior corrective fusion of spinal deformity with myelomeningocele: a series of 6 cases.

To show a modified placement of the navigation reference frame in posterior corrective fusion of spinal deformity with myelomeningocele. This was a retrospective, single-surgeon case series, and IRB-approved study. Six consecutive patients (one male and five females) who were diagnosed with spinal deformity with myelomeningocele underwent posterior corrective fusion surgery from the upper thoracic spine to the pelvis with preoperative computed tomography navigation (pCTN). At the level of the spina bifida, where posterior elements such as the spinous process were missing, the reference frame of the pCTN was placed on the flipped lamina or pedicles, and a pedicle screw (PS) or iliac screw (IS) was inserted. Screw deviation was investigated by using postoperative CT. A total of 55 screws were placed at the spina bifida level and pelvis. Of these, 12 ISs were placed on each side in each case. The screws placed using the pCTN were not reinserted or removed intraoperatively or postoperatively. However, only one PS was found to have perforated the spinal canal on postoperative CT but was left in place because it caused no neurological problem. By modifying the placement of the reference frame, such as placing it on the flipped lamina or pedicles, pCTN could be used even at the levels of the spina bifida, where the posterior elements are missing, to accurately place PSs and various types of ISs.