Image Merge Tailored Access Resection (IMTAR) of Spinal Intradural Tumors. Technical Report of 13 Cases

Systematic Review Comparing Open Versus Minimally Invasive Surgical Management of Intradural Extramedullary Tumours (IDEM)

Background/Objectives: Intradural extramedullary (IDEM) spinal tumours are relatively rare and predominantly benign. Gross total resection (GTR) has been demonstrated as an effective treatment, with increasing evidence supporting the use of minimally invasive techniques to achieve GTR. This study reviews the current surgical management options for IDEM tumours and their outcomes. Methods: A systematic literature search without meta-analysis was conducted by two independent reviewers in December 2024. The population of interest comprised patients who underwent surgical treatment for IDEM tumours. Outcomes assessed included the extent of resection, postoperative neurological function, and complications. Results: Fifty-seven articles met the inclusion criteria, providing data on 4695 IDEM cases, of which 3495 were managed through open surgery and 750 via minimally invasive surgery. The extent of resection was high, with a mean GTR > 90% across studies. Open laminectomy and unilateral minimally invasive hemilaminectomy were the most common surgical approaches. Complications, such as cerebrospinal fluid leaks, were less frequent following minimally invasive procedures vs. open surgery (11.1% vs. 14.3%). Minimally invasive surgery also led to improved postoperative functional outcomes (mean McCormick score change -1.30 vs. -0.64) and a lower recurrence rate (1.4% vs. 10.0%). Conclusions: Whilst open surgery yields acceptable rates of resection and neurological improvement, there is growing evidence that minimally invasive surgery can achieve comparable, if not superior, rates of resection with fewer complications, leading to lower costs and shorter hospital stays.

Magnetic resonance bone imaging: applications to vertebral lesions

MR bone imaging is a recently introduced technique, that allows visualization of bony structures in good contrast against adjacent structures, like CT. Although CT has long been considered the modality of choice for bone imaging, MR bone imaging allows visualization of the bone without radiation exposure while simultaneously allowing conventional MR images to be obtained. Accordingly, MR bone imaging is expected as a new imaging technique for the diagnosis of miscellaneous spinal diseases. This review presents several sequences used in MR bone imaging including black bone imaging, ultrashort/zero echo time (UTE/ZTE) sequences, and T1-weighted 3D gradient-echo sequence. We also illustrate clinical cases in which spinal lesions could be effectively demonstrated on MR bone imaging, performed in most cases using a 3D gradient-echo sequence at our institution. The lesions presented herein include degenerative diseases, tumors and similar diseases, fractures, infectious diseases, and hemangioma. Finally, we discuss the differences between MR bone imaging and previously reported techniques, and the limitations and future perspectives of MR bone imaging.

Indications for Fusion With Intradural Spine Tumor Resection in Adults: A Systematic Review and Meta-analysis

BACKGROUND

The evidence for instrumented fusion in the setting of degenerative, traumatic, or congenital deformity is well established. Data on fusion indications in intradural spinal tumors (IDST) are scarce and reduced to retrospective studies. The objective of this work is to systematically review the published literature since 2015 and analyze the change of practice patterns for stabilization and fusion after intradural tumor resection in adults.

METHODS

A systematic literature review was performed via PubMed with the terms: "intradural spinal tumors", "intramedullary spinal tumors", and "intraspinal tumors". The analysis was limited to adult patients with IDST and studies with more than 10 patients. Data on the proportion of patients who underwent instrumentation and had postoperative deformity was pooled in a meta-analysis.

RESULTS

A total of 1073 articles were identified and 47 papers were selected. All the studies were retrospective series and a total of 2473 patients were included. The follow-up ranged from 1 to 96 months, the pooled spinal fixation rate was 6% (95% CI 4.5%-7.6%), the pooled laminoplasty rate was 14.4% (95% CI 5.9%-23%), the pooled rate of postoperative deformity or malalignment in patients with a follow up of at least 6 months was 2.1% (95% CI 1.2%-3%) and just 7 patients were reoperated due to progressive deformity.

CONCLUSIONS

Based on existing evidence, the rate of fusion during resection of intradural spinal tumors is low. Prophylactic fixation is often unnecessary and only indicated in unique cases that require extensive bony resection.

Pure endoscopic minimally invasive surgery with a non‑expandable tubular retractor for intradural extramedullary spinal tumors

Minimally invasive spinal surgery (MISS) for intradural extramedullary (IDEM) spinal tumors is a safe and effective surgical strategy. Currently, various tubular retractors are widely used in the MISS of IDEM spinal tumors, primarily relying on microscopic visualization. To the best of the authors' knowledge, there is no report of pure endoscopic surgery with parallel non-expandable tubular retractors for IDEM spinal lesions. The present study reports a case series of IDEM spinal tumors that were treated via pure endoscopic MISS with a parallel non-expandable tubular retractor. The extent of tumor resection was evaluated by comparing preoperative and postoperative magnetic resonance imaging (MRI). The initial and follow-up clinical conditions were assessed according to the visual analog scale for pain and the modified McCormick scale for neurological status. Postoperative MRI demonstrated that all cases had achieved a gross total resection. After the operation, the clinical symptoms of all patients were significantly improved and there were no serious postoperative complications. At the initial follow-up, the pain experienced by the patients was significantly reduced or had even disappeared, and the neurological deficit was improved by at least one grade on the modified McCormick scale. The present report indicates that pure endoscopic MISS with a parallel non-expandable tubular retractor may be an effective and safe surgical strategy for IDEM spinal tumor resection.

Comparison of Neuroendoscopic and Microscopic Surgery for Unilateral Hemilaminectomy: Experience of a Single Institution

Objective

This study was designed to compare the safety and efficacy of unilateral hemilaminectomy conducted under complete neuroendoscopic visualization (UHNV) relative to unilateral hemilaminectomy under total microscopic visualization (UHMV) for the treatment of patients diagnosed with intraspinal tumors.

Methods

In total, 41 patients undergoing intraspinal tumor resection at Northern Jiangsu People's Hospital were included in this study, including 20 and 21 patients in the UHNV and UHMV groups, respectively. Intraoperative parameters including incision length, operative duration, number of vertebral laminae removed and intraoperative blood loss, as well as indicators of curative efficacy such as total tumor resection rates and postoperative symptom improvement rates, and safety indicators including complication rates, recurrence rates, spinal deformity rates, spinal instability incidence, and length of stay (LOS), were compared between the two groups.

Results

In contrast to the UHMV group, patients in the UHNV group had a significantly shorter incision length and decreased intraoperative blood loss (P < 0.05), while the operative duration (P > 0.05) showed no statistical difference. Although the postoperative improvement and total tumor resection rates were enhanced, the difference was not statistically significant (P > 0.05). In comparison, the bedridden time and length of stay (LOS) were significantly shortened (P < 0.05) in the UHNV group. However, there were no significant differences in recurrence, incidence of complications, spinal deformity, and spinal instability (P > 0.05).

Conclusion

Collectively, our findings indicate that UHNV is not inferior to the UHMV approach. Moreover, due to its safe and minimally invasive nature, UHNV represents a promising alternative to UHMV as a treatment for patients with intradural extramedullary tumors.

Magnetic Resonance Imaging Versus Computed Tomography for Three-Dimensional Bone Imaging of Musculoskeletal Pathologies: A Review

Magnetic resonance imaging (MRI) is increasingly utilized as a radiation‐free alternative to computed tomography (CT) for the diagnosis and treatment planning of musculoskeletal pathologies. MR imaging of hard tissues such as cortical bone remains challenging due to their low proton density and short transverse relaxation times, rendering bone tissues as nonspecific low signal structures on MR images obtained from most sequences. Developments in MR image acquisition and post‐processing have opened the path for enhanced MR‐based bone visualization aiming to provide a CT‐like contrast and, as such, ease clinical interpretation. The purpose of this review is to provide an overview of studies comparing MR and CT imaging for diagnostic and treatment planning purposes in orthopedic care, with a special focus on selective bone visualization, bone segmentation, and three‐dimensional (3D) modeling. This review discusses conventional gradient‐echo derived techniques as well as dedicated short echo time acquisition techniques and post‐processing techniques, including the generation of synthetic CT, in the context of 3D and specific bone visualization. Based on the reviewed literature, it may be concluded that the recent developments in MRI‐based bone visualization are promising. MRI alone provides valuable information on both bone and soft tissues for a broad range of applications including diagnostics, 3D modeling, and treatment planning in multiple anatomical regions, including the skull, spine, shoulder, pelvis, and long bones.

[Intraoperative ultrasound-assisted surgery of spinal tumors]

OBJECTIVE

To improve technique of intraoperative ultrasound-assisted microsurgery of spinal tumors.

MATERIAL AND METHODS

There were 68 patients with 70 spinal tumors who underwent intraoperative ultrasound-assisted resection between 2007 and 2018. Age of patients varied from 21 to 80 (mean 48.5±14.3). Intradural tumors were diagnosed in 54 (79.4%) patients (of them intramedullary in 16 (23.5%) and extramedullary in 38 (55.9%) cases). Fourteen patients (20.6%) had extradural tumors. Intraoperative ultrasound was used to determine localization, margins and structure of tumors, interrelations with neural structures, zones of dura opening and myelotomy. We also assessed quality of resection and spinal decompression.

RESULTS

In surgery of spinal tumors, intraoperative ultrasound allows to localize the tumor with 95.3% sensitivity, determine the character of its growth, shape, size and internal structure. One can also differentiate the margins of neoplasm, control accuracy of approach, select the optimal zone for dura opening and myelotomy, objectively assess spinal cord and nerve roots decompression in real-time mode. Quality of intraoperative ultrasonography images is comparable to preoperative MRI, and even exceed resolution of MR scans in some cases.

CONCLUSION

In our study, intraoperative ultrasound has proven to be a method complementing preoperative CT and MRI. This approach provides additional data in real-time mode to form a complete picture of surgical area, increase accuracy of manipulations and reduce surgical trauma.

Feasibility of unilateral hemilaminectomy utilizing a Williams retractor for the resection of intradural-extramedullary spinal neoplasms

BACKGROUND

While open approaches have historically been used in the surgical treatment of intradural-extramedullary spine tumors, minimally-invasive surgical (MIS) techniques are frequently applied to minimize post-operative complications associated with open surgery. Tubular retractor systems in particular have been employed in combination with the unilateral hemilaminectomy (UHL) approach. Here we describe the use of a Williams retractor as a safe and effective minimally-invasive alternative to tubular retractor systems with similar post-operative outcomes.

METHODS

We retrospectively reviewed a cohort of eight patients who underwent unilateral hemilaminectomy using a Williams retractor for the minimally-invasive resection of intradural-extramedullary neoplasms at a large tertiary academic center from 2017 to 2019. Patient demographics, pathologic specimens, radiographic studies, and intraoperative parameters were collected and analyzed.

RESULTS

In our series, gross total resection was achieved in all cases. Average operative time was 158±40minutes, the mean estimated blood loss (EBL) was 44.4±30.4mL, and mean length of stay was three days. All patients reported symptomatic improvement at follow-up as reported by Visual Analog Scale scores.

CONCLUSION

A Williams retractor yields similar outcomes with respect to post-operative pain, operative time, and EBL as it maintains the advantages of the UHL approach in the resection of intradural-extramedullary spine tumors while enhancing feasibility and providing significant cost savings.

Novel Applications of Spinal Navigation in Deformity and Oncology Surgery-Beyond Screw Placement

Computer-assisted navigation has made a major impact on spine surgery, providing surgeons with technological tools to safely place instrumentation anywhere in the spinal column. With advances in intraoperative image acquisition, registration, and processing, many surgeons are now using navigation in their practices. The incorporation of navigation into the workflow of surgeons continues to expand with the evolution of minimally invasive techniques and robotic surgery. While numerous investigators have demonstrated the benefit of navigation for improving the accuracy of instrumentation, few have reported applying this technology to other aspects of spine surgery. Surgeries to correct spinal deformities and resect spinal tumors are technically demanding, incorporating a wide range of techniques not only for instrumentation placement but also for osteotomy planning and executing the goals of surgery. Although these subspecialties vary in their objectives, they share similar challenges with potentially high complications, invasiveness, and consequences of failed execution. Herein, we highlight the utility of using spinal navigation for applications beyond screw placement: specifically, for planning and executing osteotomies and guiding the extent of tumor resection. A narrative review of the work that has been done is supplemented with illustrative cases demonstrating these applications.

Image-Guided Navigation and Robotics in Spine Surgery

Image guidance (IG) and robotics systems are becoming more widespread in their utilization and can be invaluable intraoperative adjuncts during spine surgery. Both are highly reliant upon stereotaxy and either pre- or intraoperative radiographic imaging. While user-operated IG systems have been commercially available longer and subsequently are more widely utilized across centers, robotics systems provide unique theoretical advantages over freehand and IG techniques for placing instrumentation within the spine. While there is a growing plethora of data showing that IG and robotic systems decrease the incidence of malpositioned screws, less is known about their impact on clinical outcomes. Both robotics and IG may be of particular value in cases of substantial deformity or complex anatomy. Indications for the use of these systems continue to expand with an increasing body of literature justifying their use in not only guiding thoracolumbar pedicle screw placement, but also in cases of cervical and pelvic instrumentation as well as spinal tumor resection. Both techniques also offer the potential benefit of reducing occupational exposures to ionizing radiation for the operating room staff, the surgeon, and the patient. As the use of IG and robotics in spine surgery continues to expand, these systems' value in improving surgical accuracy and clinical outcomes must be weighed against concerns over cost and workflow. As newer systems incorporating both real-time IG and robotics become more utilized, further research is necessary to better elucidate situations where these systems may be particularly beneficial in spine surgery.

Novel Technique of Coregistered Intraoperative Computed Tomography and Preoperative Magnetic Resonance Imaging and Diffusion Tensor Imaging Navigation in Spinal Cord Tumor Resection

Background: Intradural spinal tumors are surgically challenging lesions, and intraoperative spinal navigation offers clear potential assistance. While intraoperative computed tomography (iCT) of bony anatomy is routinely performed, coregistration with magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI) to facilitate intradural spinal tumor resection is not widely described. We present 2 cases in which iCT was coregistered with MRI and DTI for navigational guidance in the resection of intradural spinal tumors to assess technical feasibility and surgical efficacy. Case Series: Navigation using coregistered iCT/MRI was used in the resection of one extramedullary and one intramedullary cervicomedullary tumor. The iCT was obtained following open midline exposure of bony anatomy. The images were then coregistered with preoperative MRI sequences to allow for optical tracking navigation via an optical tracking station (Brainlab). For the intramedullary tumor, preoperative DTI sequences were also coregistered for enhanced identification of relevant anatomy. Navigational accuracy for all cases was confirmed to be acceptable at the level of the posterior bony elements, the dura, and the tumor-parenchyma interface. Conclusion: The coregistration of preoperative MRI sequences and iCT images allowed for meaningfully enhanced navigation during resection. In the case involving the intramedullary cervicomedullary tumor with marked distortion of longitudinal tracts, iCT/DTI navigation allowed for accurate visualization of critical structures and facilitated delineation of tumor margins that otherwise would have been difficult. The use of combined iCT and preoperative MRI/DTI neuronavigational guidance is an effective approach in the resection of intradural extramedullary and intramedullary spinal cord tumors.