Intraoperative Iso-C Research Articles

Radiofrequency ablation under 3D intraoperative Iso-C C-arm navigation for the treatment of osteoid osteomas.

To evaluate the efficacy of intraoperative three-dimensional (3D) Iso-C C-arm-navigated percutaneous radiofrequency ablation (RFA) of osteoid osteomas. 35 patients (20 males and 15 females) with osteoid osteomas underwent treatment with intraoperative 3D Iso-C C-arm navigation-guided RFA. The tumour was first biopsied for pathological examination, the core needle was removed and the RFA needle was inserted into the nidus. Post-operative X-rays and CT scans were performed to evaluate the degree of ablation and to assess for recurrence at 3-month follow-up. Patients also completed a visual analogue scale (VAS) both pre-operatively and 3 days post-operatively to subjectively assess pain. Pathological diagnosis confirmed osteoid osteoma in 19 cases. The other 16 cases were not pathologically diagnosed owing to inadequate biopsy specimens. In all cases, localized pain was immediately relieved following RFA. Patients reported significantly decreased pain, with mean pre-operative VAS scores of 3.4 reducing to 0.80 at 3 days post-operatively and further to 0.06 at 3-month follow-up (p < 0.05). The mean follow-up time was 15.5 months (range: 3-38 months). 3D Iso-C C-arm navigation-guided RFA is a safe and effective option for the treatment of osteoid osteomas and may be considered in place of intraoperative CT-guided and open resection. C-arm image-guided percutaneous RFA mitigates the need for pre-operative CT as well as intraoperative scintigraphy, provides real-time imaging of the anatomy, facilitates accurate resection of the tumour and enables immediate confirmation of excision.

Safety of Cervical Pedicle Screw Insertion in Children

Prospective clinical and radiological analysis of children with complex cervical deformities for the safety of cervical pedicle screw insertion. To analyze the possibility, safety, and efficacy of cervical pedicle screw insertion in complex pediatric cervical deformities for which conventional stabilization techniques would not have provided rigid fixation. Although the use of cervical pedicle screws (CPS) in adults has become established, the feasibility and safety of their application in children have not been described previously in the literature. Sixteen children of mean age 9.7 ± 2.6 years (range: 3-13) requiring spinal stabilization for craniovertebral junction anomalies (n = 10), cervicothoracic kyphosis/kyphoscoliosis (n = 5), and cervical tumor excision (n = 1) formed the study group. Feasibility of CPS insertion was assessed by computer tomography (CT) images. Standard 3.0-mm titanium pedicle screws were inserted using intraoperative Iso-C C-arm-based 3-dimensional computer navigation, and the containment was postoperatively evaluated with CT scan. On the basis of preoperative CT imaging, 55 pedicles were selected for screw fixation. Intraoperatively, CPS was successfully inserted at 51 levels; at 4 sclerosed pedicles (7.3%), screws could not be inserted. At 42 levels, the screws were inserted in the classical description of pedicle screw application; in 9 deformed vertebra, the screws were inserted in a nonclassical fashion, taking purchase in the 3 columns of the cervical vertebra. Forty-five (88.3%) screws were fully contained, 6 (11.7%) had a noncritical breach, and none had a critical breach. No perioperative complications related to pedicle screw insertion were noted. Safe insertion of cervical pedicle screws is possible in children. Iso-C navigation provides real-time virtual imaging and improves the safety and accuracy of successful pedicle fixation even in altered vertebral anatomy. Pedicle width morphometrics do not restrict screw insertion.

Poster 67: Intraoperative Use of 3-D Imaging in the Repair of Maxillofacial Trauma: A Single Institution's Experience

Intraoperative imaging with mobile computed tomography (CT) systems has been described with promising results (Tomoscan M in the United States and Europe; Iso-C C-arm in Europe); we describe the successful use of intraoperative Iso-C C-arm in the United States in addition to our transition to the even more user-friendly O-arm, of which this would be the first publication describing its use in maxillofacial surgery. This mobile three-dimensional imaging system (O-arm) can be wheeled into an operating room on demand during an operation and used to perform intraoperative imaging confirmation of fracture reduction, bone graft placement, and/or hardware placement.

Anterior single screw fixation of odontoid fracture with intraoperative iso-C 3-dimensional imaging

The purpose of this study was to assess the value of isocentric C-arm three-dimensional (Iso-C 3D) fluoroscopy for the insertion of an anterior odontoid screw. The results of the Iso-C 3D group were compared with that of an historic control group using conventional fluoroscopy. Twenty-nine patients diagnosed with type II or rostral-type III odontoid fractures were treated with a single anterior screw fixation in this study. The Iso-C 3D group included 13 patients and the other 16 patients were in the historic control group. All operations were performed by a single surgeon using standard procedure and manner. The clinical and radiographic results were recorded and compared between the two groups. The fluoroscopy time in the Iso-C 3D group was 42.9s as compared to 68.1s in the control group (P<0.01). The mean operative time was 91.5min in the Iso-C 3D group when compared with 81.6min in the control group (P=0.20). The rate of bony fusion was 96.6% (28/29), the failure rate of reduction or fixation was 13.8% (7.7% in Iso-C 3D group; 18.8% in control group). The Smiley-Webster scale showed that 90% of patients achieved good or better outcomes In conclusion, this technique can be safely extended to the treatment of technically difficult to treat spinal injuries and at the same time reduce total radiation exposure time both for the patient and the surgeon.

Is Intraoperative CT of Posterior Cervical Spine Instrumentation Cost-effective and Does It Reduce Complications?

Symptomatic multilevel cervical myelopathy is often addressed using posterior decompression using two-dimensional fluoroscopy. Intraoperative three-dimensional fluoroscopy provides more accurate information on the position of instrumentation to prevent screw-related complications. We documented the incidence of hardware-related complications and evaluate cost-effectiveness when using intraoperative three-dimensional fluoroscopy (ISO-C CT) in posterior cervical spine surgery. Records from 87 patients who underwent posterior cervical decompression and instrumented fusion for multilevel cervical spondylosis with myelopathy were retrospectively reviewed. Patients in whom a lateral mass, pars, or pedicle screw was removed or revised based on intraoperative ISO-C CT was recorded. Cost analysis was performed using 2008 Medicare reimbursements and was compared against cost estimates for ISO-C CT. Seven patients (8%) had screws changed based on the results of the three-dimensional fluoroscopy: 0.5% of lateral mass screws, 3.1% of thoracic pedicle screws, and 15% of C2 pars screws. No patients who had evaluation of hardware with the ISO-C CT required a return to surgery for complications secondary to hardware failure, malposition, or cutout. Cost savings are achieved if use of intraoperative ISO-C CT prevents eight patients from requiring a return to the operating room. If every malpositioned screw has the potential to be symptomatic, then 240 patients must have screws placed to be cost-effective. ISO-C CT can safely replace postoperative CT as the standard of care in patients undergoing posterior cervical spinal fusion. Level III, economic and decision analyses. See Guidelines for Authors for a complete description of levels of evidence.

Endonasal endoscopic resection of the odontoid process in a nonachondroplastic dwarf with juvenile rheumatoid arthritis: feasibility of the approach and utility of the intraoperative Iso-C three-dimensional navigation

The authors report a case of a nonachondroplastic dwarf with severe basilar invagination and compression of the cervicomedullary junction (CMJ) due to juvenile rheumatoid arthritis. Initially excellent reduction of the invagination and decompression of the CMJ was achieved using posterior fixation. However, 1 month postoperatively symptoms recurred and the authors found imaging evidence of recurrence as well. The patient subsequently underwent an endoscopic transnasal resection of the dens with assistance of Iso-C navigation. He recovered well and tolerated regular diet on postoperative Day 2.

Intraoperative Iso-C Three-Dimensional Navigation in Excision of Spinal Osteoid Osteomas

A prospective observational study on the use of Iso-C 3-dimensional navigated surgery in treating 4 patients with spinal osteoid osteomas by a minimally invasive approach. To report on the efficacy of Iso-C 3-dimensional intraoperative spinal navigation in excising osteoid osteomas. Curative treatment of osteoid osteomas entails complete intralesional excision of the nidus. However, intraoperative localization of the nidus can be difficult, and may involve wide resection of the surrounding normal bony structure resulting in instability requiring fusion or inadvertent neurovascular injury. Computer navigation provides real-time multiplanar images of the vertebral anatomy, and has been used extensively to increase the accuracy of pedicle screw placement. However, the efficacy of this technology in intraoperative localization and excision of spinal tumors is still largely unknown. Iso-C 3-dimensional intraoperative navigation was used to localize osteoid osteomas of the spine in 4 patients. A minimally invasive reflective array, tool navigator, and a registered burr were used for localization and deroofing of the lesion, followed by curettage and high-speed burring of the cavity. Complete removal of the nidus was confirmed intraoperatively by reacquisition of data. In all 4 patients, Iso-C 3-dimensional computer navigation was successful in accurate localization of the osteoid osteomas. The tool navigator was helpful to localize and deroof the lesion. The ability to register the burr was useful to clear the lesion without removal of any excess bone. Reregistration allowed intraoperative confirmation of adequacy of excision. Conservation of bone allowed early mobilization and also removed the need for reconstruction. Postoperative computer tomography scan done in 2 patients confirmed complete extirpation of the nidus. Histopathology confirmed the clinical diagnosis in all cases. All patients had immediate relief of the characteristic pain after surgery and were asymptomatic at 2 years follow-up. Intraoperative Iso-C 3-dimensional navigation is useful in accurately localizing and guiding complete excision of spinal osteoid osteomas through a minimally invasive approach without compromising spinal stability.

Role of intraoperative Iso-C based navigation in challenging spine trauma

Background:Pedicle screw fixation is the most preferred method of stabilizing unstable spinal fractures. Pedicle screw placement may be difficult in presence of fractured posterior elements, deformed spine, gross instability and spinal pathology. Challenging spine-fracture fixation is defined as the presence of one or more of the following: 1) obscured topographical landmarks as in ankylosing spondylitis, 2) fractures in occipitocervical or cervicothoracic regions and 3) preexisting altered spinal alignment. We report a series of pedicle screw insertion with guidance of navigation in difficult fixation problems..Materials and Methods:Fourteen patients [hangman's fracture (n=3), odontoid fracture (n=4), C1C2 fracture (n=1) and spinal fracture with coexistent ankylosing spondylitis (n=6)] underwent posterior stabilization. Intraoperatively after surgical exposure, images were acquired by Iso-C 3D C-arm and transferred to navigation system. Instrumentation was performed with navigational assistance. Postoperatively, placements of pedicle screws were evaluated with radiographs and CT scan.Results:Sixty-seven pedicle screws (cervical, n=33; thoracic, n=6; lumbar, n=26; sacral n=2) and 15 lateral mass screws were inserted with navigation guidance. The average time of image data acquisition by Iso-C 3D C-arm and its transfer to workstation was 4 minutes (range, 2-6 minutes). Postoperative CT scan revealed ideal placement of screws in 63 pedicles (94%), grade 1 cortical breaches (<2 mm) in 3 pedicles (4.5%) and grade 2 cortical breach (2-4 mm) in one pedicle (1.5%). There were no neurovascular complications. Deep infection was encountered in one case, which settled with debridement.Conclusions:Intraoperative Iso-C 3D C-arm based navigation is a useful adjunct while stabilizing challenging spinal trauma, rendering feasibility, accuracy and safety of pedicle screw placement even in difficult situations.

Intraoperative Iso-C C-arm Navigation in Cervical Spinal Surgery

Fifty-two study participants underwent cervical spine surgery using intraoperative Iso-C imaging with or without spinal navigation. To evaluate prospectively the feasibility, advantages, limitations, and applications of Iso-C in cervical spine surgery. Existing stereotactic spinal navigational systems images must be acquired before surgery and typically require cumbersome point-to-point registration. Intraoperative computed tomography (CT) and magnetic resonance imaging (MRI) provide real-time information but can restrict access to the patient, preclude the use of traditional operating room tables, and are time-consuming. The Iso-C allows quick, CT-quality, real-time data acquisition without restricting access to the patient. The data acquired can be automatically transferred to navigational systems with the immediate ability to navigate for anterior or posterior cervical spine procedures. High-resolution isotropic three-dimensional data sets were acquired using the Iso-C intraoperative fluoroscopy in 52 cervical spine cases. In 30 cases, the data were imported automatically to the StealthStation Treon to support neuronavigation. In 22 cases, a postprocedural intraoperative CT was obtained with the Iso-C primarily to assess the extent of osseous decompression and/or the accuracy of implants or instrumentation. In most cases, a postoperative high-resolution CT image was obtained and compared with the Iso-C data. Successful automated registration suitable for navigation was attained for all anterior and posterior cervical spinal cases. The postprocedural intraoperative Iso-C data were 100% concordant with those of postoperative high-resolution CT as determined by a blinded neuroradiologist. Iso-C intraoperative fluoroscopy is an accurate and rapid way to perform CT-quality image-guided navigation in cervical spinal surgery. In most cases, it obviates the need for postoperative imaging.

Announcement

OBJECTIVE: The intraoperative Iso-C C-arm (Siremobil Iso-C 3D; Siemens Medical Solutions, Erlangen, Germany) provides a unique ability to acquire and view multi-planar three-dimensional images of intraoperative anatomy. Registration for intraoperative surgical navigation may be automated, thus simplifying the operative workflow. METHODS: Iso-C C-arm intraoperative fluoroscopy acquires 100 images, each of which must be 1.8 degrees in a circumferential fashion about an “isocentric” point in space. The system generates a high-resolution isotropic three-dimensional data set that is available immediately after the 90-second C-arm rotation. The data set is ported to the image-guided workstation, registration is immediate and automated, and the surgeon can navigate with millimetric accuracy. The authors prospectively examined data from the initial 60 patients examined with the Iso-C, among whom were cases of anterior and posterior spinal instrumentation from the occiput to the sacrum. Percutaneous and minimally invasive spinal and cranial procedures were also included. RESULTS: Automated registration for image-guided navigation was attainable for anterior and posterior cases from the cranial base and entire spine. In most cases, intraoperative postprocedural imaging with the Iso-C mitigated the need for postoperative imaging. CONCLUSION: Intraoperative Iso-C three-dimensional scanning allows real-time feedback during cranial base and spinal surgery and during procedures involving instrumentation. In most cases, it obviates the need for postoperative computed tomography. Its usefulness is in its simplicity, and it can be easily adapted to the operating room workflow. When coupled with intraoperative navigation, this new technology facilitates complex neurosurgical procedures by improving the accuracy, safety, and time of surgery.