Feasibility and safety report on robotic assistance for cervical pedicle screw fixation: a cadaveric study.

This cadaveric study aimed to evaluate the safety and usability of a novel robotic system for posterior cervical pedicle screw fixation. Three human cadaveric specimens and C2-T3 were included. Freshly frozen human cadaver specimens were prepared and subjected to robot-assisted posterior cervical pedicle screw fixation using the robotic system. The accuracy of screw placement, breach rate, and critical structure violations were evaluated. The results were statistically compared with those of previous studies that used different robotic systems for cervical pedicle screw fixation. The robotic system demonstrated a high accuracy rate in screw placement. A significant number of screws were placed within predetermined safe zones. The total entry offset was 1.08 ± 0.83 mm, the target offset was 1.86 ± 0.50 mm, and the angle offset was 2.14 ± 0.77°. Accuracy rates comparable with those of previous studies using different robotic systems were achieved. The system was also feasible, allowing precise navigation and real-time feedback during the procedure. This cadaveric study validated the safety and usability of the novel robotic system for posterior cervical pedicle screw fixation. The system exhibited high precision in screw placement, and the results support the extension of the indications for robot-assisted pedicle screw fixation from the lumbar spine to the cervical spine.

Identification of predictive factors for better outcomes in LINAC-based radiation treatment for cerebral cavernous malformation.

The effectiveness of radiation therapy in the treatment of cerebral cavernous malformations (CCM) remains debatable. However, numerous studies have shown a reduction in hemorrhage risk following radiotherapy for CCM. Therefore, herein, we share our experiences utilizing linear accelerator (LINAC)-based radiation for treating CCMs, with the aim of identifying the key factors influencing the therapeutic outcomes. We conducted a retrospective review of all patients with non-brainstem CCMs who underwent radiation treatment, as recorded in the NOVALIS registry at our institution. T2-weighted MR images were used for volumetric assessments using the iPlan radiotherapy planning software. To determine the independent predictors of nidus volume reduction and perilesional brain edema (PBE), we performed multivariate Cox regression analysis to calculate hazard ratios. Twenty patients with 31 non-brainstem CCMs were enrolled in this study. Analysis revealed age as an independent predictive factor for both nidus volume reduction and PBE after radiation treatment for CCM. Furthermore, a single fraction dose of 17 Gy or more was identified as an independent predictor of nidus volume decrease, while a single fraction dose of 18 Gy or more was found to be an independent risk factor for PBE in patients with CCM following LINAC-based radiation therapy. LINAC-based radiation therapy for non-brainstem CCMs with a single fraction radiation dose between 16.5 and 17.5 Gy, or a biologically equivalent dose of approximately 120 Gy, may be the most effective at reducing nidus volume and limiting side effects, particularly in patients under the age of 55 years. We further observed that the risk of PBE increased as the maximum radiation dose delivered to a 1 cc volume of the surrounding normal brain exceeded approximately 17.3 Gy. Therefore, we believe that calculating the D1cc of the normal brain may help to predict the occurrence of PBE when radiotherapy is administered to non-brainstem CCMs.

A Propensity Score-Matched Cohort Study Comparing 3 Different Spine Pedicle Screw Fixation Methods: Freehand, Fluoroscopy-Guided, and Robot-Assisted Techniques.

OBJECTIVE: This study aimed to compare the accuracy of robotic spine surgery and conventional pedicle screw fixation in lumbar degenerative disease. We evaluated clinical and radiological outcomes to demonstrate the noninferiority of robotic surgery. METHODS: This study employed propensity score matching and included 3 groups: robot-assisted mini-open posterior lumbar interbody fusion (PLIF) (robotic surgery, RS), c-arm guided minimally invasive surgery transforaminal lumbar interbody fusion (C-arm guidance, CG), and freehand open PLIF (free of guidance, FG) (54 patients each). The mean follow-up period was 2.2 years. The preoperative spine condition was considered. Accuracy was evaluated using the Gertzbein-Robbins scale (GRS score) and Babu classification (Babu score). Radiological outcomes included adjacent segmental disease (ASD) and mechanical failure. Clinical outcomes were assessed based on the visual analogue scale, Oswestry Disability Index, 36-item Short Form health survey, and clinical ASD rate. RESULTS: Accuracy was higher in the RS group (p < 0.01) than in other groups. The GRS score was lower in the CG group, whereas the Babu score was lower in the FG group compared with the RS group. No significant differences were observed in radiological and clinical outcomes among the 3 groups. Regression analysis identified preoperative facet degeneration, GRS and Babu scores as significant variables for radiological and clinical ASD. Mechanical failure was influenced by the GRS score and patients' age. CONCLUSION: This study showed the superior accuracy of robotic spine surgery compared with conventional techniques. When combined with minimally invasive surgery, robotic surgery is advantageous with reduced ligament and muscle damage associated with traditional open procedures.

Three-Dimensional Quantitative Assessment of Pedicle Screw Accuracy in Clinical Utilization of a New Robotic System in Spine Surgery: A Multicenter Study.

OBJECTIVE: The objective of this study was to evaluate the accuracy of pedicle screw placement in patients undergoing percutaneous pedicle screw fixation with robotic guidance, using a newly developed 3-dimensional quantitative measurement system. The study also aimed to assess the clinical feasibility of the robotic system in the field of spinal surgery. METHODS: A total of 113 patients underwent pedicle screw insertion using the CUVIS-spine pedicle screw guide system (CUREXO Inc.). Intraoperative O-arm images were obtained, and screw insertion pathways were planned accordingly. Image registration was performed using paired-point registration and iterative closest point methods. The accuracy of the robotic-guided pedicle screw insertion was assessed using 3-dimensional offset calculation and the Gertzbein-Robbins system (GRS). RESULTS: A total of 448 screws were inserted in the 113 patients. The image registration success rate was 95.16%. The average error of entry offset was 2.86 mm, target offset was 2.48 mm, depth offset was 1.99 mm, and angular offset was 3.07°. According to the GRS grading system, 88.39% of the screws were classified as grade A, 9.60% as grade B, 1.56% as grade C, 0.22% as grade D, and 0.22% as grade E. Clinically acceptable screws (GRS grade A or B) accounted for 97.54% of the total, with no reported neurologic complications. CONCLUSION: Our study demonstrated that pedicle screw insertion using the novel robot-assisted navigation method is both accurate and safe. Further prospective studies are necessary to explore the potential benefits of this robot-assisted technique in comparison to conventional approaches.

Risk Factors for Prevertebral Soft Tissue Swelling Following Single-Level Anterior Cervical Spine Surgery.

OBJECTIVE: Anterior cervical spine surgery (ACSS) is a common surgical procedure used to treat cervical spinal degenerative diseases. One of the complications associated with ACSS is prevertebral soft tissue swelling (PSTS), which can result in airway obstruction, dysphagia, and other adverse outcomes. This study aims to investigate the correlation between various cervical sagittal parameters and PSTS following single-level ACSS, as well as to identify independent risk factors for PSTS. METHODS: A retrospective study conducted at a single institution. The study population included all patients who underwent single-level ACSS between January 2014 and December 2022. Patients with a history of cervical spine surgery or trauma were excluded from the study. The presence and severity of PSTS was assessed by reviewing pre- and postoperative imaging studies. The potential risk factors for PSTS that were examined include patient age, sex, body mass index, tobacco use, comorbidities, serum albumin levels, operative time, implant type, implanted level, and various cervical spine sagittal parameters. Multivariate linear regression analysis was performed to identify the independent risk factors for PSTS. RESULTS: A total of 62 consecutive patients who underwent single-level ACSS over a 8-year period at a single institution were enrolled in this study. Only preoperative segmental angle showed positive correlation with PSTS among various cervical spine sagittal parameters (r=0.36, p=0.005). Artificial disc replacement showed a negative correlation with PSTS (ß=-0.38, p=0.002), whereas the use of demineralized bone matrix (DBM) had a positive impact on PSTS (ß=0.33, p=0.009). We found that male sex, lower preoperative serum albumin, and implantation of upper cervical level (above C5) were independent predictors for PSTS after single-level ACSS (ß=1.21; 95% confidence interval [CI], 0.27 to 2.15; p=0.012; ß=-1.63; 95% CI, -2.91 to -0.34; p=0.014; ß=1.44; 95% CI, 0.38 to 2.49; p=0.008, respectively). CONCLUSION: Our study identified male sex, lower preoperative serum albumin levels, and upper cervical level involvement as independent risk factors for PSTS after single-level ACSS. These findings can help clinicians monitor high-risk patients and take preventive measures to reduce complications. Further research with larger sample sizes and prospective designs is needed to validate these findings.

Relationship between the atlantodental interval and T1 slope after atlantoaxial fusion in patients with rheumatoid arthritis.

BACKGROUND: Atlantoaxial fusion has been widely used for the treatment of atlantoaxial instability (AAI). However, atlantoaxial fusion sacrifices the motion of atlantoaxial articulation, and postoperative loss of cervical lordosis and aggravation of cervical kyphosis are observed. We investigated various factors under the hypothesis that the atlantodental interval (ADI) and T1 slope may be associated with sagittal alignment after atlantoaxial fusion in patients with rheumatoid arthritis (RA). METHODS: We retrospectively investigated 64 patients with RA who underwent atlantoaxial fusion due to AAI. Radiological factors, including the ADI, T1 slope, Oc-C2 angle, cervical sagittal vertical axis, and C2-C7 angle, were measured before and after surgery. RESULTS: The various factors associated with atlantoaxial fusion before and after surgery were compared according to the upper and lower preoperative ADIs. There was a significant difference in the T1 slope 1 year after surgery (p = 0.044) among the patients with lower preoperative ADI values. The multivariate logistic regression analysis showed that the preoperative ADI (> 7.92 mm) defined in the receiver-operating characteristic curve analysis was an independent predictive factor for the increase in the T1 slope 1 year after atlantoaxial fusion (odds ratio, 4.59; 95% confidence interval, 1.34-15.73; p = 0.015). CONCLUSION: We found an association between the preoperative ADI and difference in the T1 slope after atlantoaxial fusion in the patients with RA. A preoperative ADI (> 7.92 mm) was an independent predictor for the increase in the T1 slope after atlantoaxial fusion. Therefore, performing surgical treatment when the ADI is low would lead to better cervical sagittal alignment.

Effects of Possible Osteoporotic Conditions on the Recurrence of Chronic Subdural Hematoma.

The recurrence rate of chronic subdural hematoma (CSDH) has been reported to range from 2.3 to 33%. As bridging veins are composed of abundant collagen bundles and bone matrix, we aimed to investigate the possible associations between skull Hounsfield unit (HU) values and the recurrence of CSDH. We retrospectively enrolled patients with CSDH who underwent burr hole surgery. The HU values of the frontal skull were measured on brain CT scans. The cumulative hazard for recurrence was estimated according to predictive factors. To identify the independent predictors associated with the recurrence of CSDH, hazard ratios (HRs) were estimated using multivariate Cox regression analysis. A total of 208 consecutive patients who underwent burr hole trephination for CSDH over a 7-years period at a single institution were enrolled in this study. We found that age, greater midline shift (≥10.5 mm), lower skull HU (<769.5), and diabetes were independent predictors for the recurrence of CSDH (HR 1.06, 95% confidence interval [CI] 1.00-1.12, p = 0.042; HR 5.37, 95% CI 1.48-19.46, p = 0.010; HR 6.71, 95% CI 1.84-24.45, p = 0.004; and HR 3.30, 95% CI 1.05-10.43, p = 0.042, respectively). A relationship between possible low bone mineral density (BMD) and CSDH recurrence was observed. In addition, age, greater preoperative midline shift, and diabetes were also identified as predictive factors for recurrence. We expect that our findings may facilitate our understanding of the possible association between CSDH and BMD.

Large Mature Cystic Teratoma of the Third Ventricle in Infancy: A Case Report and Review of Literatures.

Teratomas of the central nervous system are rare and are frequently found in children and young adults. Cystic teratomas found in infancy is a well-recognized but infrequent entity. Intracranial teratomas,like teratomas in general, tend to arise from midline structures such as the pineal gland, but has rarely been found in the third ventricle. We report a rare case of a 6-month-old infant with a mature cystic teratoma of the third ventricle with a review of literatures.