Virtual pathology of cervical radiculopathy based on 3D MR/CT fusion images: impingement, flattening or twisted condition of the compressed nerve root in three cases

[Brief history and application prospect of robotic spine surgery]

Spinal robotics has rounded out twenty years in clinical, is mainly used for pedicle screw placement at present, can significantly increase the accuracy of screw placement and reduce radiation exposure to the patient and the surgeon. In the future, haptic feedback, automatic collision avoidance, and other technologies will further expand its application to complete precise operations such as decompression and correction, providing safety guarantee for the implementation of complex spinal surgery.

Development of a Robotic Spine Surgery Program: Rationale, Strategy, Challenges, and Monitoring of Outcomes After Implementation

Surgical robots were invented in the 1980s, and since then, robotic-assisted surgery has become commonplace. In the field of spine surgery, robotic assistance is utilized mainly to place pedicle screws, and multiple studies have demonstrated that robots can increase the accuracy of screw placement and reduce radiation exposure to the patient and the surgeon. However, this may be at the cost of longer operative times, complications, and the risk of errors in mapping the patient's anatomy.

Computed Tomography and Magnetic Resonance Imaging Overlay in the Spine for Surgical Planning: A Technical Report

BACKGROUND

Computed tomography (CT) and magnetic resonance imaging (MRI) studies are used separately for surgical planning of spine surgery. Advanced techniques exist for creating CT-MR fusion images, but at this time these techniques are not easily accessible for large-scale use.

TECHNIQUE

We propose a simple graphical technique for CT-MR image overlay, for use in the surgical planning of spinal decompression and guidance of intraoperative resection. The proposed technique involves overlaying a single cross-section from anatomically comparable MRI and CT studies on any software with basic image editing functions.

RESULTS

We demonstrate CT-MR fusion images of 8 patients of the senior author in which the technique was used. We found that it can also be referenced intraoperatively for navigation.

CONCLUSIONS

Compared to other techniques, our proposed method can be easily implemented by clinicians to create simple CT-MRI fusion images that can be useful for preoperative planning and intraoperative navigation.

Morphological analysis of Kambin's triangle using 3D CT/MRI fusion imaging of lumbar nerve root created automatically with artificial intelligence

PURPOSE

We developed a software program that automatically extracts a three-dimensional (3D) lumbar nerve root image from magnetic resonance imaging (MRI) lumbar nerve volume data using artificial intelligence. The aim of this study is to evaluate the morphology of Kambin's triangle in three dimensions based on an actual endoscopic transforaminal surgical approach using three-dimensional (3D) computed tomography (CT)/ magnetic resonance imaging (MRI) fusion images of the lumbar spine and nerve tissue.

METHODS

Three-dimensional lumbar spine/nerve images of 100 patients (31 males and 69 females; mean age, 66.8 years) were used to evaluate the relationship between the superior articular process (SAP), exiting nerve root (ENR), and dural canal at the L2/3, L3/4, and L4/5 levels at 45° and 60° approach angles.

RESULTS

The SAP-ENR distance at 60° was the greatest at L4/5 and was significantly greater at L2/3 and L4/5 than at L3/4 (P < 0.01, P < 0.01, respectively). The SAP-ENR distance at 45° was the greatest at L2/3, and it was larger in L2/3 and L4/5 than in L3/4 (P < 0.01, P < 0.01, respectively). The SAP-ENR distances at L4/5 were significantly greater at 60° than at 45° (P < 0.01). The dural canal was located within Kambin's triangle on the plane of the upper endplate of the lower vertebra at L2/3 in 41.5% of the cases and at L3/4 in 14% of the cases at 60° but not at L4/5.

CONCLUSION

The 3D lumbar spine/nerve image enabled a combined assessment of the positional relationship between the SAP, ENR, and dural canal to quantify the safety zone of practical endoscopic spinal surgery using a transforaminal approach. Three-dimensional lumbar spine/nerve images could be useful for examining parameters, including bones and nerves, to ensure the safety of surgery.

The Application of Virtual Reality in Cervical Spinal Surgery: A Review

In recent years, clinicians have used virtual reality (VR) to simulate real-world environments for medical purposes. The use of VR systems in the field of cervical spine surgery can lead to effective surgical training programs without causing harm to patients. Moreover, both imaging and VR can be used before surgery to assist preoperative surgical planning. VR devices have a variety of built-in motion sensors, therefore kinematic data can be recorded while users are wearing VR devices and performing some actions for the evaluation of cervical spine activity and exercise ability. Therapists have also applied VR to cervical spine rehabilitation and showed good results. At present, the application of VR systems in cervical spine surgery has great potential, but current research is insufficient. Here, we review the latest advancements in VR technology used in cervical spine surgery and discuss potential directions for future work.

Virtual Reality-Based Evaluation of Surgical Planning and Outcome of Monosegmental, Unilateral Cervical Foraminal Stenosis

BACKGROUND

Foraminal cervical nerve root compression can be caused by lateral disk herniation or osteophyte formation of the vertebrae. Improved diagnosis and evaluation can be achieved using different imaging techniques: radiographs, computed tomography (CT), and magnetic resonance imaging. We retrospectively evaluated the potential influence of a virtual reality (VR) visualization technique on surgery planning and evaluation of postoperative results in patients with monosegmental, unilateral osseous cervical neuroforaminal stenosis.

METHODS

Seventy-three patients were included. Ventral decompression of the neuroforamen was performed in 41 patients, dorsal decompression in 32 patients. Patients' files were evaluated. CT scans were visualized via VR software to measure the smallest cross-sectional area of the intervertebral neuroforamen in the lateral resection region. A questionnaire evaluated the influence of VR technique on surgical planning and strategy.

RESULTS

The VR-technique had a moderate influence on the choice of the approach (ventral or dorsal), a significant influence on the ventral approach strategy, and no influence on the positioning of the patient or the dorsal approach strategy. A significant difference was found in the size of the smallest cross-sectional area of the intervertebral neuroforamen in the lateral resection region between ventral and dorsal approaches, with no correlation to the clinical outcome.

CONCLUSIONS

Reconstruction of pre- and postoperative 2D-CT images of the cervical spine into 3D images, and the spatial and anatomical reconstructions in VR models, can be helpful in planning surgical approaches and treatment strategies for patients with cervical foraminal stenoses, and for evaluation of their postoperative results.

Utility of Oblique Sagittal Reformatted and Three-dimensional Surface Reconstruction Computed Tomography in Foraminal Stenosis Decompression

Determining the responsible level of cervical radiculopathy can be difficult. Because asymptomatic findings are common in cervical radiculopathy, diagnoses based on imaging studies can be inaccurate. Therefore, we investigated whether the application of oblique sagittal reformatted computed tomography (oblique sagittal CT) and three-dimensional surface reconstruction CT (3DCT) affects surgical plans for patients with cervical foraminal stenosis and whether it assists diagnosis of foraminal stenosis. Accordingly, four reviewers, with office notes, observed the CT and magnetic resonance imaging (MRI) images of 18 patients undergoing surgical treatment for cervical radiculopathy. After reviewing the MRI and sagittal, coronal, and axial CT images, the reviewers recorded the operation to be performed; they examined oblique sagittal CT and 3DCT images of the same patients and noted any differences from their surgical plans. Consequently, we analyzed these changes in the decompressed foramina in the surgical plan; mean percent change in the plan was 18.1%. Inter-rater reliability improved from κ - 0.194 to κ - 0.240. Therefore, the addition of oblique and 3DCT images improves inter-rater reliability owing to changes in a part of decompressed foramina. The addition of oblique sagittal CT and 3DCT is helpful in evaluating the foramen and planning surgical treatment of cervical radiculopathy.

Coronal oblique orientation of the neural foramen improves cervical spine MRI: A comparison of the sensitivity of different angulations

OBJECTIVE

Angulated projections are used in radiography to show the cervical neural foramen. Imaging the coronal oblique planes in an MRI of the cervical spine should therefore improve visualization of neural foramen pathology. This has to be demonstrated.

PATIENTS AND METHODS

A multi-center investigation of 40 patients with monoradiculopathy and 10 healthy controls was undertaken. T2-weighted sagittal, coronal oblique and axial slices were individually and separately examined by four readers blinded to the diagnosis. The statistical evaluation compared against the clinical gold standard of the neurological diagnosis of a single nerve root irritation or lesion.

RESULTS

The sensitivity/specificity required to detect the relevant neural foramen pathology was 0.47/0.60 for axial, 0.57/0.90 for sagittal and 0.55/0.70 for coronal oblique scans. The readers felt significantly more confident in attributing the cause of pathology using coronal oblique planes. Interreader reliability was moderate to substantial, with the highest values for the sagittal planes (0.39-0.76) and lower values for the transversal and coronal oblique planes (0.15-0.63). Intrareader reliability was substantial, with values between 0.53 and 0.88. Reading the axial planes was significantly more time consuming than reading the other planes.

CONCLUSION

The use of coronal oblique planes in cervical spine MRIs increases sensitivity and confidence in attributing the cause of neural foramen obstruction. They are easy to interpret and demand less reading time than axial planes, and so the inclusion of coronal oblique planes in the workup of cervical spine MRI is recommended, at least when neural foramen pathology is suspected.

Three-dimensional visualization of internal vertebral venous plexuses relative to dural sac and spinal nerve root of spinal canal stenosis using MRI

PURPOSE

The aim of this study was to introduce a new method of producing three-dimensional (3D) images of vertebral venous plexuses (VVPs) by 3D-MRI with and without contrast media, to identify pathoanatomical features that might accelerate or modify spinal canal stenosis.

METHODS

We used a 1.5-T MRI unit with two different 3D sequences with and without contrast media. Multi planar reconstruction (MPR) images of VVPs could be obtained by volume image subtraction methods with a workstation for dural sac from whole 3D volume MPR without contrast media, using images before and after gadoteridol injection. Three patients with degenerative lumbar spine disease and one with cervical ossification of the posterior longitudinal ligament (OPLL) were studied with and without contrast media. As three patients underwent operations, we investigated intraoperative microscopic findings, and compared VVP images.

RESULTS

Abundant components of internal VVPs were identified on MRI in correlation with neural tissues such as dura and nerve roots.

CONCLUSIONS

Using 3D MRI without and with gadoteridol, we can evaluate morphological changes in VVP under degenerative spinal conditions. The MR anatomy of VVPs of the spine is important, as it has been implicated in many pathophysiological mechanisms and may also cause pitfalls in MRI.

[Utility of coronal oblique slices in cervical spine MRI: Improved detection of the neuroforamina]

BACKGROUND AND OBJECTIVES

Angulated projections are standard in conventional radiography of the cervical spine, but rarely used in magnetic resonance imaging (MRI). As neuroforaminal pathology plays an important role in the etiology of radicular syndromes and may influence an operative approach, the utility of coronal oblique slices in MRI is explored.

MATERIALS AND METHODS

In a retrospective setting, 25 consecutive patients with neurologically diagnosed cervical monoradiculopathy were identified. T2-weighted sagittal, coronal oblique, and transversal slice orientations were anonymized. Two radiologists and two neurosurgeons independently assessed the cases. Criteria were site, cause, and grading of the neuroforaminal stenosis and the level of confidence on a 100-point visual analog scale (VAS). We computed interrater agreement, sensitivity, and t tests.

RESULTS

Using only one slice orientation, the sensitivity in detecting the relevant neuroforamen was 0.40 for transversal, 0.68 for sagittal, and 0.64 for coronal oblique scans. A combination of the different angulations increased sensitivity and in 4 cases only the coronal oblique scans proved diagnostic. The readers felt significantly more confident in attributing the cause of the pathology on coronal oblique planes (a mean of 72 VAS points, p = 0.0003 vs 58 (sagittal) vs 64 (transversal)). Interrater agreement was significantly better for experienced (kappa 0. 48) than for inexperienced readers (0.32, p = 0.02).

CONCLUSIONS

Adding coronal oblique planes in cervical spine MRI increases sensitivity and confidence in attributing the cause of neuroforaminal pathology. They are regarded as useful by all the readers.