Neuronavigational guidance in craniofacial approaches for large (para)nasal tumors involving the anterior skull base and upper clival lesions

Assessing the feasibility of the transmastoid infralabyrinthine approach without decompression of the jugular bulb to the extradural part of the petrous apex and petroclival junction prior to surgery

BACKGROUND AND OBJECTIVE

This study aims to define specific measurements on cranial high-resolution computed tomography (HRCT) images prior to surgery to prove the feasibility of the navigated transmastoid infralabyrinthine approach (TI-A) without rerouting of the facial nerve (FN) and decompression of the jugular bulb (JB) in accessing the extradural-intrapetrous part of petrous bone lesions located at the petrous apex and petroclival junction.

MATERIALS AND METHODS

Vertical and horizontal distances of the infralabyrinthine space were measured on cranial HRCT images prior to dissection. Subsequently, the area of access was measured on dissected human cadaveric specimens. Infralabyrinthine access to the extradural part of the petrous apex and petroclival junction was evaluated on dissected specimens by two independent raters. Finally, the vertical and horizontal distances were correlated with the area of access.

RESULTS

Fourteen human cadaveric specimens were dissected bilaterally. In 54% of cases, the two independent raters determined appropriate access to the petrous apex and petroclival junction. A highly significant positive correlation (r = 0.99) was observed between the areas of access and the vertical distances. Vertical distances above 5.2 mm were considered to permit suitable infralabyrinthine access to the extradural area of the petrous apex and petroclival junction.

CONCLUSIONS

Prior to surgery, vertical infralabyrinthine distances on HRCT images above 5.2 mm provide suitable infralabyrinthine access to lesions located extradurally at the petrous apex and petroclival junction via the TI-A without rerouting of the FN and without decompression of the JB.

Skull-Base Surgery—A Narrative Review on Current Approaches and Future Developments in Surgical Navigation

Surgical navigation technology combines patient imaging studies with intraoperative real-time data to improve surgical precision and patient outcomes. The navigation workflow can also include preoperative planning, which can reliably simulate the intended resection and reconstruction. The advantage of this approach in skull-base surgery is that it guides access into a complex three-dimensional area and orients tumors intraoperatively with regard to critical structures, such as the orbit, carotid artery and brain. This enhances a surgeon’s capabilities to preserve normal anatomy while resecting tumors with adequate margins. The aim of this narrative review is to outline the state of the art and the future directions of surgical navigation in the skull base, focusing on the advantages and pitfalls of this technique. We will also present our group experience in this field, within the frame of the current research trends.

Surgical treatment of selected tumors via the navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach without rerouting of the facial nerve

The feasibility of a novel skull base approach - the navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach (NaMIPSI-A) without rerouting of the fallopian canal for selected jugular foramen tumors (JFTs) - has been demonstrated in a neuroanatomical laboratory study. Here, we present our clinical experience with the NaMIPSI-A for selected JFTs, with a particular focus on its efficacy and safety. All patients with JFTs who were treated via the NaMIPSI-A were included in this study. The JFTs were classified according to a modified Fisch classification. The neurological and neuroradiological outcome, the extent of tumor resection, and the approach-related morbidity were examined. Five patients (two women, three men; mean age 57 years, range 48-65) were available. According to the modified Fisch classification, two JFTs were graded as C1, one as De1, and two as De2. Gross total resection (GTR) was achieved in three patients and near-total resection (NTR) in two. Postsurgically, no new neurological deficits and no approach-related morbidity and mortality occurred. One case with a postoperative cerebrospinal fluid leak was managed successfully with lumbar drainage. During the follow-up period (mean 67.6 months, range 12-119 months), tumor recurrence was noted in the NTR group but not in the GTR group. The NaMIPSI-A to the jugular foramen without rerouting of the fallopian canal is highly valuable for selected tumors of the jugular foramen. It is less invasive than other skull base approaches, and it allows safe and complete tumor removal in appropriate patients.

Image-guided surgery in otolaryngology: A review of current applications and future directions in head and neck surgery

Image-guided surgery (IGS) has become a widely adopted technology in otolaryngology. Since its introduction nearly three decades ago, IGS technology has developed rapidly and improved real-time intraoperative visualization for a diverse array of clinical indications. As usability, accessibility, and clinical experiences with IGS increase, its potential applications as an adjunct in many surgical procedures continue to expand. Here, we describe the basic components of IGS and review both the current state and future directions of IGS in otolaryngology, with attention to current challenges to its application in surgery of the nonrigid upper aerodigestive tract.

Advanced Magnetic Resonance Imaging of the Skull Base

Magnetic resonance (MR) imaging is a crucial tool for evaluation of the skull base, enabling characterization of complex anatomy by utilizing multiple image contrasts. Recent technical MR advances have greatly enhanced radiologists' capability to diagnose skull base pathology and help direct management. In this paper, we will summarize cutting-edge clinical and emerging research MR techniques for the skull base, including high-resolution, phase-contrast, diffusion, perfusion, vascular, zero echo-time, elastography, spectroscopy, chemical exchange saturation transfer, PET/MR, ultra-high-field, and 3D visualization. For each imaging technique, we provide a high-level summary of underlying technical principles accompanied by relevant literature review and clinical imaging examples.

Open resection and reconstruction of a Nasoseptal Chondrosarcoma: case report and literature review

BACKGROUND

Primary chondrosarcomas of the nasal septum are rare, with a variety of clinical features that evade detection and treatment. While endoscopic surgery has become increasingly accessible, open approaches may be needed to provide adequate visualization for tumour ablation and reconstruction. We report the resection and reconstructive considerations of a septal chondrosarcoma.

CASE PRESENTATION

A 75-year-old woman presented with a 3-year history of a slow growing, firm mass in the nasal tip causing protrusion and septal fullness. Computed Tomography scan of the paranasal sinuses revealed a well-circumscribed, 2.2 cm mass at the anterior nasal septum extending into the right vestibule. Biopsy of the cartilaginous lesion confirmed the diagnosis of a low-grade chondrosarcoma by histopathology. The tumour was removed using a transcolumellar open rhinoplasty approach with a large septal resection. Primary reconstruction of the surgical defect was performed using an L-shaped strut from the nasal keystone area to the columella. Follow-up examinations demonstrated no evidence of recurrent disease with satisfactory functional and cosmetic outcomes at 1-year.

CONCLUSION

This report describes a case of nasal septal chondrosarcoma successfully treated with surgical excision using an open rhinoplasty approach. Only 5-10% of chondrosarcomas are located in the head and neck region and arise rarely in the nasal septum in approximately 2-4%. With this mass, an open rhinoplasty approach was required to allow optimal exposure of the margins and to facilitate reconstruction without disruption of normal sinonasal anatomy and function. Although rare, chondrosarcoma of the nasal septum should be considered in the differential diagnosis of nasal masses.

[Use of navigation in skull base surgery]

The review briefly presents the history of development of navigation systems in neurosurgery. The idea of the existing principles underlying the navigation systems used in neurosurgery is given. Currently, the basic principles of navigation are optical and electromagnetic. Studies are presented comparing the accuracy of various navigation systems. Optical navigation demonstrates greater accuracy compared to electromagnetic, but both methods demonstrate a submillimeter error in the experiment. The history of use of navigation in the surgery of the skull base is analyzed in detail, the most relevant areas of use of navigation within the surgery of the skull base are considered: craniofacial reconstruction, endoscopic endonasal surgery, surgery of common tumors of the skull base affecting the infratemporal, pterygopalatine fossa, temporomandibular joint. Indications for the use of navigation, limitations of the methodology are explained.

Severe Cerebral Complications Secondary to Perforation Injury of the Anterior Skull Base During Sinonasal Surgery: An Underappreciated Problem?

OBJECTIVE

Functional endonasal sinus surgery (FESS) is widely practiced and is considered a generally safe procedure. Skull base injuries occur in <1% of procedures and are typically associated with cerebrospinal fluid leaks. Rarely, skull base injuries might result in cerebral lesions. Here we present a series of 4 patients with iatrogenic perforating injuries of the anterior skull base and cerebral lesions after routine FESS.

METHODS

Four patients with iatrogenic perforating cerebral lesions after routine FESS, performed at other institutions, were referred to a tertiary neurosurgery department. Within a 10-year period these procedures were performed in 3 patients as endoscopic FESS and as a microscopic FESS in 1 patient.

RESULTS

There were 3 men and 1 woman. Mean age at the time of surgery was 50 years. In 3 instances (in which an endoscope was used), the ear, nose, and throat physician had noted perforation of the skull base during surgery, but it went unnoticed in 1 patient operated with the microscope. Frontal lobe hematoma occurred in all patients, and in 3 of them cerebral infarction developed secondary to injury of branches of the anterior cerebral artery. Three patients developed acute hydrocephalus. Two had rapid global brain swelling and they succumbed within days. The other 2 patients survived without apparent neurological deficits.

CONCLUSIONS

Cerebral lesions during FESS still occur in contemporary surgery and they are possibly underreported. Even with prompt conservative and surgical measures, these lesions may result in catastrophic outcome. Associated vascular injuries have a worse prognosis. The only risk factor associated with lethal outcome in our series was younger age.

Preoperative surgical simulation and validation of the line of resection in anterolateral craniofacial resection of advanced sinonasal sinus carcinoma

BACKGROUND

The purpose of this study was to assess the usefulness and accuracy of preoperative 3D virtual simulation of anterolateral craniofacial resection in cases of advanced sinonasal sinus carcinoma.

METHODS

Seven patients with advanced (T4 classification) sinonasal sinus carcinoma who underwent anterolateral craniofacial resection in our hospital between 2011 and 2013 were included in this study. Postsimulation CT images were fused with postoperative CT images and differences between the planned and actual osteotomy were measured in 3 regions of the skull base.

RESULTS

The differences ranged from 0 mm to 5.8 mm (average, 3.1 mm) at the inferior wall of the cavernous sinus, from 0.8 mm to 8.3 mm (average, 3.5 mm) at the inferior wall of the sphenoid sinus, and from 0 mm to 13.6 mm (average, 2.3 mm) in the palatine bone.

CONCLUSION

Preoperative 3D virtual surgical simulation and postoperative feedback can contribute to training for surgeons. © 2016 Wiley Periodicals, Inc. Head Neck 39: 512-519, 2017.

[Transnasal endoscopic surgery of neoplasms in the children with the use of the CT-navigation systems]

The objective of the present article was to report the current literature data concerning the significance of and prospects for the application of the CT-navigation systems in transnasal endoscopic surgery of neoplasms localized in the nasal cavity, nasopharynx, paranasal sinuses, and the base of the skull in the children.

Minimally invasive surgery of the anterior skull base: transorbital approaches

Minimally invasive approaches are becoming increasingly popular to access the anterior skull base. With interdisciplinary cooperation, in particular endonasal endoscopic approaches have seen an impressive expansion of indications over the past decades. The more recently described transorbital approaches represent minimally invasive alternatives with a differing spectrum of access corridors. The purpose of the present paper is to discuss transorbital approaches to the anterior skull base in the light of the current literature. The transorbital approaches allow excellent exposure of areas that are difficult to reach like the anterior and posterior wall of the frontal sinus; working angles may be more favorable and the paranasal sinus system can be preserved while exposing the skull base. Because of their minimal morbidity and the cosmetically excellent results, the transorbital approaches represent an important addition to established endonasal endoscopic and open approaches to the anterior skull base. Their execution requires an interdisciplinary team approach.

Electromagnetic navigation-guided surgery in the semi-sitting position for posterior fossa tumours: a safety and feasibility study

BACKGROUND

Electromagnetic (EM)-guided neuronavigation is an innovative technique and a viable alternative to opto-electric navigation. We have performed a safety and feasibility study using EM-guided neuronavigation for posterior fossa surgery in the semi-sitting position in a selected subset of patients.

METHODS

Out of 284 patients with posterior fossa tumours operated upon over a period of 40 months, a subset of 15 patients was thought to possibly benefit from EM navigational guidance and was included in this study. There were six children and nine adults (aged between 8 and 84 years; mean age, 34.6 years) with different neoplasms in the brainstem or close to the midline. All patients had contrast-enhanced three-dimensional (3D) magnetic resonance imaging (MRI) of the head preoperatively. EM-guided navigation was used to identify and preserve the venous sinuses during craniotomy and to determine the trajectory to the lesion using various approaches. Neuronavigation accuracy was repeatedly checked for deviations measured in millimetres on screen shots during surgery before and after dural opening in the coronal (z = vertical), axial (x = mediolateral) and sagittal (y = anteroposterior) plane.

RESULTS

Referencing of the patient in the supine position was fast and easy. There was no loss of navigation accuracy after repositioning of the patient in the semi-sitting position (mean, 2.5 mm ± 0.92 mm). Identification of the pathological structure using EM navigation was achieved in all instances. Optimal angulation of the neck was selected individually to permit a comfortable position for the surgeon with full access to the lesion avoiding over-flexion. Deviation of accuracy at the surface of the target lesion ranged between 2.5 and 5.8 mm (mean, 3.9 mm ± 1.1 mm).

CONCLUSIONS

EM-guided neuronavigation in the semi-sitting position was safe and technically feasible. It enabled fast and accurate referencing without loss of navigation accuracy despite repositioning of the patient. In contrast to conventional opto-electric neuronavigation there were no line of sight problems.

Augmented real-time navigation with critical structure proximity alerts for endoscopic skull base surgery

OBJECTIVES/HYPOTHESIS

Image-guided surgery (IGS) systems are frequently utilized during cranial base surgery to aid in orientation and facilitate targeted surgery. We wished to assess the performance of our recently developed localized intraoperative virtual endoscopy (LIVE)-IGS prototype in a preclinical setting prior to deployment in the operating room. This system combines real-time ablative instrument tracking, critical structure proximity alerts, three-dimensional virtual endoscopic views, and intraoperative cone-beam computed tomographic image updates.

STUDY DESIGN

Randomized-controlled trial plus qualitative analysis.

METHODS

Skull base procedures were performed on 14 cadaver specimens by seven fellowship-trained skull base surgeons. Each subject performed two endoscopic transclival approaches; one with LIVE-IGS and one using a conventional IGS system in random order. National Aeronautics and Space Administration Task Load Index (NASA-TLX) scores were documented for each dissection, and a semistructured interview was recorded for qualitative assessment.

RESULTS

The NASA-TLX scores for mental demand, effort, and frustration were significantly reduced with the LIVE-IGS system in comparison to conventional navigation (P < .05). The system interface was judged to be intuitive and most useful when there was a combination of high spatial demand, reduced or absent surface landmarks, and proximity to critical structures. The development of auditory icons for proximity alerts during the trial better informed the surgeon while limiting distraction.

CONCLUSIONS

The LIVE-IGS system provided accurate, intuitive, and dynamic feedback to the operating surgeon. Further refinements to proximity alerts and visualization settings will enhance orientation while limiting distraction. The system is currently being deployed in a prospective clinical trial in skull base surgery.

Management of sinonasal chondrosarcoma: a systematic review of 161 patients

BACKGROUND

This study reviews the published literature related to management of sinonasal chondrosarcoma. Clinical presentation, demographics, radiographic diagnosis, treatment, and management outcomes of this uncommon disease are reported.

METHODS

A systematic review of studies for sinonasal chondrosarcoma from 1950 to 2012 was conducted. A PubMed search for articles related to this condition, along with bibliographies of the selected articles was performed. Articles were examined for patient data that reported survivability. Demographic data, disease site, treatment strategies, follow-up, outcome, and survival were analyzed.

RESULTS

A total of 63 journal articles were included, comprising a total of 161 cases of sinonasal chondrosarcoma. The average follow-up was 77.4 months (range, 1 to 325.2 months). Surgical resection was the most common treatment modality, used in 72.0% of cases. A combination of surgery and radiation therapy was the second most commonly used treatment modality, used in 21.7% of cases.

CONCLUSION

This review contains the largest pool of sinonasal chondrosarcoma patients to date and suggests aggressive surgical resection is the most common treatment modality for this condition. The use of adjuvant radiotherapy for prevention of local recurrence after subtotal or total resection has not been proven effective. However, the use of radiotherapy in addition to surgical resection has shown benefit in some studies in terms of survival.

Endoscopic endonasal compared with anterior craniofacial and combined cranionasal resection of esthesioneuroblastomas

OBJECTIVE

Esthesioneuroblastomas represent a surgical challenge because of their anatomical location, the necessity of achieving negative margins, and the often-cosmetically disfiguring transfacial approaches needed. Recently, expanded endonasal endoscopic approaches have been developed, either alone or in combination with a craniotomy. We conducted a systematic review of case series and case reports to compare outcomes between these various surgical approaches.

METHODS

A MEDLINE search was conducted of the modern literature (1985-2010) to identify open and endoscopic surgical series. Tumor and patient characteristics, Kadish stage, extent of resection, and progression-free and overall survival were recorded and analyzed by approach. Kaplan-Meier analysis was used to assess overall survival and progression-free survival.

RESULTS

Forty-seven studies comprising 453 patients were included. The endoscopic cohort had a greater proportion of Kadish Stage A tumors compared with the craniofacial group. Gross total resection was achieved in 98.1% of patients who underwent an endoscopic approach compared with 81.3% for the craniofacial and 100% for the cranionasal cohorts. Local recurrence occurred in 8.0% of patients in the endoscopic group compared with 22.1% in the craniofacial and 16.7% in the cranionasal cohorts.

CONCLUSION

In well-selected cases, cranionasal and endonasal approaches can be safe and effective. An ongoing evaluation of the benefits and limitations are necessary to better define the ideal patient population and patient-specific risk factors for the use of these minimal access techniques.

Navigated minimally invasive presigmoidal suprabulbar infralabyrinthine approach to the jugular foramen without rerouting of the facial nerve

BACKGROUND

Jugular foramen tumors are rare and challenging lesions for skull base surgeons because of their difficult operative accessibility. Various surgical approaches to the jugular foramen have been described to overcome the morbidity of standard petrosectomy.

OBJECTIVE

To describe the surgical anatomy of a novel route to the jugular foramen without opening the fallopian canal, the navigated tailored presigmoidal suprabulbar infralabyrinthine approach.

METHODS

Ten cadaver heads were dissected under navigational guidance on both sides to examine the advantages and limitations of the presigmoidal suprabulbar infralabyrinthine approach without opening the fallopian canal. Mastoidectomy was performed by using a high-speed drill. Under navigation guidance, the sigmoid sinus, jugular bulb, posterior semicircular canal, and fallopian canal were located and preserved. The jugular foramen with the extradural part of the IXth, Xth, and XIth nerve were identified.

RESULTS

Measurements of the surgical corridor and exposed petrous bone area on high-resolution computed tomography showed that the navigated presigmoidal suprabulbar infralabyrinthine approach without opening the fallopian canal is a suitable route for extradural jugular foramen lesions with limited extension (approach height 5.59 ± 0.16 mm; approach width 7.68 ± 0.18 mm; approach surface 33.73 ± 1.37 mm; approach depth 32.92 ± 0.21 mm; vertical angle α of the surgical approach 41.3° ± 0.9°; horizontal angle β of the surgical approach 40.5° ± 0.6°).

CONCLUSION

The navigation-guided presigmoidal suprabulbar infralabyrinthine approach is a minimally invasive approach for selected lesions of the jugular foramen with preservation of the fallopian canal, labyrinthine block, and sigmoid sinus. This approach is suited for C1, De1, De2, Di1, and Di2 tumors according to the Fisch classification.

Endoscopic skull base surgery: a comprehensive comparison with open transcranial approaches

Little data exists comparing endoscopic endonasal approaches to pathology of the anterior skull base with more traditional transcranial and transsphenoidal microscopic approaches. In order to more fully characterize the role of endoscopy in the management of pathology of the anterior cranial base, we conducted a systematic review of case series and case reports documenting surgical and clinical outcomes. We found that for craniopharyngiomas, clival chordomas, esthesioneuroblastomas and giant pituitary adenomas, the endonasal endoscopic approach can result in equivalent or higher rates of gross total resection than open approaches. For meningiomas, however, open transcranial approaches are still able to achieve higher rates of total resection. CSF leak rates are higher for patients undergoing endoscopic surgery for meningiomas and craniopharyngiomas, but not for chordomas, esthesioneuroblastomas or giant pituitary adenomas. In certain patients, the endonasal endoscopic approach may be a safe and effective alternative for the treatment of a wide variety of skull base pathology, particularly those with small midline tumours.

Computer-assisted resection and reconstruction of pelvic tumor sarcoma

Pelvic sarcoma is associated with a relatively poor prognosis, due to the difficulty in obtaining an adequate surgical margin given the complex pelvic anatomy. Magnetic resonance imaging and computerized tomography allow valuable surgical resection planning, but intraoperative localization remains hazardous. Surgical navigation systems could be of great benefit in surgical oncology, especially in difficult tumor location; however, no commercial surgical oncology software is currently available. A customized navigation software was developed and used to perform a synovial sarcoma resection and allograft reconstruction. The software permitted preoperative planning with defined target planes and intraoperative navigation with a free-hand saw blade. The allograft was cut according to the same planes. Histological examination revealed tumor-free resection margins. Allograft fitting to the pelvis of the patient was excellent and allowed stable osteosynthesis. We believe this to be the first case of combined computer-assisted tumor resection and reconstruction with an allograft.

Meningoencephalocele: a late complication of Le Fort III midfacial advancement in a patient with Crouzon syndrome

Complications of Le Fort III midfacial advancement include CSF rhinorrhea, meningitis, and ocular and cerebral injury. This report reviews the anatomy of the Le Fort III osteotomies and their relevance to the unusual complication of meningoencephalocele. In this report, a young male patient with Crouzon syndrome underwent subcranial midfacial advancement at the age of 10 years for obstructive sleep apnea and ocular exposure. He presented 4 years later complaining of nasal obstruction. On physical examination, a mucous-covered mass was noted in the left upper nasal vault medial to the turbinates. Computed tomography scanning and MR imaging confirmed the diagnosis of frontoethmoidal meningoencephalocele. Repair of the meningoencephalocele was accomplished using a combined neurosurgery and plastic surgery approach. Meningoencephalocele is a rare complication of subcranial midfacial advancement. The abnormal anatomy of the anterior cranial base in patients with syndromic craniosynostosis places them at greater risk for fracture of the cribriform plate and dural tears during this procedure. Unrecognized dural injury is the etiology of this complication in this young patient; however, elevated intracranial pressure may have been a confounding factor. Attention to the anatomy of the anterior cranial base, as seen on sagittal CT images, will aid in preventing this complication.

Posttreatment prognosis of patients with esthesioneuroblastoma

OBJECT

There is no Class I evidence to guide the appropriate management of esthesioneuroblastoma (EN). Most data currently guiding treatment come from small- or modest-sized series gathered at individual centers that have concluded that surgery with radiotherapy is the preferred treatment. In this study, the authors summarize the published literature on treatment outcomes in patients with EN. The objective was to ascertain what variables predict prognosis in these patients and to determine the relative effect of different therapies.

METHODS

The authors identified 205 published studies containing treatment outcomes for surgery, radiotherapy, chemotherapy, or multimodal treatment. Using Kaplan-Meier analysis, the survival of patients who received surgery was compared with that in those who received surgery and radiotherapy. Additionally, Kadish staging was compared with low- and high-grade Hyams criteria to assess for subgroup prognostic significance in survival differences.

RESULTS

Nine hundred fifty-six patients met the inclusion criteria, with a median follow-up time of 3 years. Kaplan-Meier analysis demonstrated no difference in survival between patients who underwent surgery alone and those who underwent surgery plus radiotherapy at 5 years (78 vs 75%) or 10 years (67 vs 61%, respectively) (p = 0.3). Univariate analysis demonstrated worse survival in cases involving Kadish Grade C tumors, Hyams Grade 3 and 4 tumors, and in patients older than 65 years of age. Multivariate analysis demonstrated that Hyams Grade 3 and 4 lesions carried significant risk (proportional hazard = 4.83, p < 0.001) with 5- and 10-year survival of 47 and 31%.

CONCLUSIONS

A biopsy should always be obtained in cases suspected of EN because histology is a strong prognostic indicator and will help guide appropriate treatment. Unimodal surgery and combined surgery/radiotherapy appear to be of equivalent efficacy with respect to survival in patients with EN. Chemotherapy should be considered in high-grade EN.

MR/CT image fusion of the spine after spondylodesis: a feasibility study

The objective of this study is to evaluate feasibility, accuracy and time requirements of MR/CT image fusion of the lumbar spine after spondylodesis. Sagittal MR and CT images derived from standard imaging protocols (sagittal T2-weighted MR/sagittal reformatted multi-planar-reformation of the CT) of the lumbar spine with correct (n = 5) and incorrect (n = 5) implant position were fused by two readers (R1, R2) using OsiriX in two sessions placing one (session 1) or two (session 2) reference point(s) on the dorsal tip(s) of the cranial and caudal endplates from the second lumbar to the first sacral vertebra. R1 was an experienced musculoskeletal radiologist; R2 a spine surgeon, both had received a short training on the software tool. Fusion times and fusion accuracy, defined as the largest deviation between MR and CT in the median sagittal plane on the ventral tip of the cranial end plate of the most cranial vertebra visible on the CT, were measured in both sessions. Correct or incorrect implant position was evaluated upon the fused images for all patients by an experienced senior staff musculoskeletal radiologist. Mean fusion time (session 1/session 2; in seconds) was 100.4/95 (R1) and 104.2/119.8 (R2). Mean fusion deviation (session 1/session 2; in mm) was 1.24/2.20 (R1) and 0.79/1.62 (R2). The correct/incorrect implant position was identified correctly in all cases. In conclusion, MR/CT image fusion of the spine with metallic implants is feasible, fast, accurate and easy to implement in daily routine work.