Background:
Cervical axial spine fusion is challenging as the anatomy is extremely variable, and screw misplacement can lead to severe complications. C1 lateral mass screws and C2 pedicle screws are ...routinely placed under either fluoroscopic guidance or imaging-assisted navigation. Here, we compared the two for axial screw placement.
Methods:
We retrospectively evaluated patients’ treated from 2011–2016 utilizing the Harm’s procedure for C1-C2 screw fixation performed under either fluoroscopic guidance (nine patients) or image-assisted O-arm navigation (five patients). The groups had similar demographic and risk factors. Variables studied included operative time, estimated blood loss (EBL), accuracy of screw placement, screw reposition rates, and reoperation rates.
Results:
The mean EBL was 555CC and 260CC, respectively (not a significant difference) utilizing fluoroscopic versus O-arm navigation. Of interest, the mean surgical duration was 27 min longer in the O-arm versus fluoroscopy group (
P
= 0.03). Ten C2 pedicle screws were performed using O-arm navigation. Alternatively, as 9 of 18 C2 pedicles were considered “risky” for the placement of fluoroscopic-guided pedicle screws, laminar screws were utilized. Although the accuracy rate of C1 and C2 screw placement was higher for the navigated group, this finding was not significant. Similarly, despite complications involving two unacceptably placed screws from the fluoroscopic guidance group, there were no neurological sequelae.
Conclusion:
Axial cervical spine instrumentation is challenging. Utilization of Imaging-assisted navigation increases the accuracy and safety of screw placement.
Titanium dioxide (TiO2) is a frequently used biomaterial, particularly in orthopedic and dental implants, and it is considered an inert and benign compound. This has resulted in toxicological ...scrutiny for TiO2 in the past decade, with numerus studies showing potential pathologic downstream effects. Herein we describe case report of a 77-year-old male with subacute CNS dysfunction, secondary to breakdown of a titanium-based carotid stent and leading to blood levels 1000 times higher (3 ppm) than the reported normal. We prospectively collected tissues adjacent to orthopedic implants and found a positive correlation between titanium concentration and time of implant in the body (r = 0.67, p < 0.02). Rats bearing titanium implants or intravascularly treated with TiO2 nanoparticles (TiNP) exhibited memory impairments. A human blood-brain barrier (BBB) in-vitro model exposed to TiNP showed paracellular leakiness, which was corroborated in-vivo with the decrease of key BBB transcripts in isolated blood vessels from hippocampi harvested from TiNP-treated mice. Titanium particles rapidly internalized into brain-like endothelial cells via caveolae-mediated endocytosis and macropinocytosis and induced pro-inflammatory reaction with increased expression of pro-inflammatory genes and proteins. Immune reaction was mediated partially by IL-1R and IL-6. In summary, we show that high levels of titanium accumulate in humans adjacent to orthopedic implants, and our in-vivo and in-vitro studies suggest it may be neurotoxic.
A definitive diagnosis of brain lesions not amenable to surgery is mainly made by stereotactic needle biopsy. The diagnostic yield and safety of the frameless versus frame-based image-guided ...stereotactic techniques is unclear. Our objective was to evaluate the safety and accuracy of frameless versus frame-based stereotactic brain biopsy techniques.
A total of 278 patients (153 men; mean age: 65.5 years) with intra-axial brain lesions underwent frame-based (n = 148) or frameless image-guided stereotactic brain biopsy (n = 130) using a minimally invasive twist drill technique during 2010–2016 at Sheba Medical Center. Demographic, imaging, and clinical data were retrospectively analyzed.
The diagnostic yield (>90%) did not differ significantly between groups. Overall morbidity (6.8% vs. 8.5%), incidence of permanent neurologic deficits (2.1% vs. 1.6%), mortality rate (0.7% vs. 0.8%), and postoperative computed tomography–detected asymptomatic (14.2% vs. 16.1%) and symptomatic (2.0% vs. 1.6%) bleeding also did not differ significantly between the frame-based and frameless cohorts, respectively. The diagnostic yield and complication rates related to the biopsy technique were not significantly associated with sex, age, entry angle to the skull and skull thickness, lesion location or depth, or radiologic characteristics. Diagnostic yield was significantly associated with the mean lesion volume. Smaller lesions were less diagnostic than larger lesions in both techniques (P = 0.043 frame-based and P = 0.048 frameless).
The frameless biopsy technique is as efficient as the frame-based brain biopsy technique with a low complication rate. Lesion volume was the only predictive factor of diagnostic yield. The minimally invasive twist drill technique is safe and efficient.
Spinal neurons operate as a processing link that integrates descending and peripheral information and in turn, generates a specific yet complex muscle command. The functional organization of spinal ...circuitry during normal motor behavior dictates the way in which this translation process is achieved. Nonetheless, little is known about this organization during normal motor behavior. We examined the spatial organization of neural activity in the cervical spinal cord of behaving primates performing an isometric wrist task by estimating the averaged intraspinal activity of neuronal populations. We measured population response profiles and frequency content around torque onset and tested the tendency of these profiles to exhibit a specific organization within the spinal volume. We found that the spatial distribution of characteristic response profiles was non-uniform; namely, sites with a specific response profile tended to have a preferred spatial localization. Physiologically, this finding suggests that specific spinal circuitry that controls a unique feature of motor actions (with a particular task-related response pattern) may have a segregated spinal organization. Second, attempts to restore motor function via intraspinal stimulation may be more successful when the spatial distribution of these task-related profiles is taken into account.
OBJECTIVE Stereotactic body radiotherapy (SBRT) is a precise and conformal treatment modality used in the management of metastatic spine tumors. Multiple studies have demonstrated its safety and ...efficacy for pain and tumor control. However, no uniform quantitative imaging methodology exists to evaluate response to treatment in these patients. This study presents radiographic local control rates post-SBRT, systematically compares measurements acquired according to WHO and Response Evaluation Criteria in Solid Tumors (RECIST) criteria, and explores the relationship to patient outcome. METHODS The authors performed a retrospective review of prospectively obtained data from a cohort of 59 consecutive patients (81 metastatic isocenters) treated with SBRT and followed with serial MRI scans. Measurements were performed by a neuroradiologist blinded to the patients’ clinical course. Local control status was determined according to both WHO and RECIST measurements, and agreement between the measuring methodologies was calculated and reported. RESULTS Eighty-one isocenters (111 vertebral bodies) were treated with SBRT. The mean treatment dose was 13.96 Gy and the median follow-up duration was 10.8 months, during which 408 MRI scans were evaluated with both WHO and RECIST criteria for each scan point. Imaging demonstrated a mean unidimensional size decrease of 0.2 cm (p = 0.14) and a mean area size decrease of 0.99 cm 2 (p = 0.03). Although 88% of the case classifications were concordant and the agreement was significant, WHO criteria were found to be more sensitive to tumor size change. The local control rates according to WHO and RECIST were 95% and 98%, respectively. CONCLUSIONS Although WHO volumetric measurements are admittedly superior for tumor size measurement, RECIST is simpler, reproducible, and for the first time is shown here to be comparable to WHO criteria. Thus, the application of RECIST methodology appears to be a suitable standard for evaluating post-SBRT treatment response. Moreover, using comprehensive and consistent measuring approaches, this study substantiates the efficacy of SBRT in the treatment of spine metastases.
This pilot study was undertaken to evaluate the safety, performance, and usability of the Xvision-Spine (XVS) System (Augmedics, Arlington Heights, IL) during open spinal fixation procedures in ...patients requiring pedicle screw placement in the lumbosacral spine.
The XVS System is an augmented reality head-mounted display (HMD) based on a computer navigation system designed to assist surgeons in accurately placing pedicle screws. It uses an HMD-mounted tracking camera to provide optical tracking technology, and provides the surgeon a translucent direct near-eye display of the navigated surgical instrument's location relative to the computed tomographic image. We report the preliminary results of a prospective series of all consecutive patients who underwent augmented reality-assisted pedicle screw placement in the lumbosacral vertebrae at 3 institutions. Clinical accuracy for each pedicle screw was graded with Gertzbein-Robbins scores by 2 independent and blinded neuroradiologists.
The 19 study participants included 8 men and 11 women with a mean age of 59.13 ± 12.09 and 59.91 ± 12.89 years, respectively. Seventeen procedures were successfully completed via the XVS System. Two procedures were not completed due to technical issues with the system's intraoperative scanner. A total of 86 screws were inserted. The accuracy of the XVS System was 97.7%.
The XVS System's performance in accurate placement of pedicle screws in the lumbosacral vertebrae had an overall accuracy of 97.7%. These preliminary results were comparable to the accuracy of other manual computer-assisted navigation systems reported in the literature.
Transmission of information in the corticospinal (CS) route constitutes the fundamental infrastructure for voluntary actions. The anatomy of this pathway has been studied extensively, but there is ...little direct evidence regarding its functional organization. Here we explored the areal specificity of CS connections by studying two related questions: the functional significance of the parallel, motor, and premotor CS pathways; and the way in which finger-related motor commands are handled by this pathway. We addressed these questions by recording from primary motor (M1) and premotor cortical sites in primates (Maccaca fascicularis) performing a motor task, while measuring the evoked intraspinal unit response to single pulse cortical stimulation. Stimulation in M1 evoked spinal neuronal responses more frequently than stimulation in premotor cortex. The number of muscles excited by M1 stimulation was higher than the number excited by premotor stimulation. Within subregions of M1 finger-related sites were sparsely connected with intermediate zone interneurons and tended to affect the ventrally located motoneurons directly. These results suggest that, despite the parallel anatomical organization, the flow of motor commands is predominantly relayed via M1 to downstream elements. The functional impact of premotor cortex is weak, possibly due to inhibitory systems that can shape the flow of information in the CS pathway. Finally, the difference in spinal processing of finger versus wrist-related motor commands points to a different motor control strategy of finger versus wrist movements.
Objective The present study evaluated the optimal measuring criteria to assess spinal tumor response to surgery followed by stereotactic spine radiosurgery (SRS) and reports the local control and ...wound complication rates following combined multimodality treatment. Methods and Materials Prospectively collected patient information was retrospectively reviewed to identify patients treated with spine surgery followed by SRS. Tumor sizes and volumetric assessment were formally measured. Local control status was defined according to World Health Organization (WHO, bidimensional), RECIST (unidimensional), or volumetric size change. Statistical comparative assessments of tumor measurements were performed. Results Twenty-two patients were eligible for evaluation after having undergone surgery followed by single-fraction SRS within a 2-month period. Seventeen had follow-up magnetic resonance imaging (MRI) with a mean patient follow-up of 12.59 months (range 3–36 months). None developed wound complication after radiation therapy (95% lower confidence bound 13%). Two patients had clinical recurrence while 15 of 17 achieved local control (88.3%). A test of marginal homogeneity for RECIST versus WHO was not statistically significant, P = 1.0 suggesting similar response classifications with both systems. Spearman correlations among 1) volumetric assessment, 2) bidimensional size, and 3) unidimensional size were significant for all groups ( P < 0.05). Conclusion High local control rates can be achieved with surgery followed by SRS. Further, adjuvant SRS following spine tumor surgery delivers less radiation to the wound than conventional radiation and thus potentially reduces wound complications. Unidimensional, bidimensional, and volumetric tumor assessments demonstrate similar results. Hence the use of the simpler RECIST criteria is suitable and appropriate for evaluating the response to treatment after spine radiosurgery.
Purpose: Application of the anterior sub-axial cervical approach to the axial spine or the high thoracic spine has been previously described. Evaluation methods to determine the feasibility of these ...approaches were also described but alternative method was utilized in the current study. We describe our experience expanding the boundaries of anterior cervical approach utilizing a novel algorithm for approach selection.
Materials and methods: A retrospective analysis of patients' files and imaging data of all anterior cervical approach to treat pathologies above C2-3 disc space or below C7-D1 disc space. The decision to proceed with standard approach was based on CT or MRI scans and the pre-operative cervical range of motion. Post-operative course and surgical complications will be discussed.
Results: During a two year period 13 patients had undergone anterior cervical approach to the axial spine (3 patients) or the thoracic spine (10 patients). Ten patients were treated for tumour resection, one for trauma, one for myelopathy and the last for infective osteomyelitis with epidural abscess. Three patients were previously operated in another hospital via the posterior approach with remaining compressive mass necessitating anterior decompression. Complications were recorded in 30% of the patients.
Conclusions: Approach to the axial or the high thoracic spine is more challenging and harbors approach-related complication. Pre-operative evaluation of patients imaging allows harnessing the standard approach for treatment of extreme levels with relative safety and efficiency. Spine surgeons' awareness to this technique may increase surgical efficacy while reducing the complication rates.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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