Minimally invasive percutaneous stabilization plus balloon kyphoplasty for the treatment of type A thoraco lumbar spine fractures: minimum 4 year's follow-up.

AIM: There is no consensus regarding the ideal treatment of type A thoraco-lumbar fractures. Many surgical techniques have been described but none has demonstrated its superiority over others. Recently, minimally invasive techniques have been widely used as they reduce the immediate morbidity related to the procedure. Percutaneous pedicle screw stabilization plus balloon kyphoplasty is a valuable technique, but there are only few data regarding clinical and radiological results in the long term. The purpose of this study was to report the long-term clinical and radiological outcome of patients undergoing minimally invasive management of thoracolumbar fracture in our institution. METHODS: This was a retrospective review of prospectively collected data. Between January 2006 and June 2008, 22 patients underwent short-segment percutaneous stabilization and balloon kyphoplasty for treatment of a type A fracture of the thoraco-lumbar spine. The study included 12 males and 10 females and the mean age was 50.5 years (25-75 years). The affected levels were T10 (N.=1), T11 (N.=1), T12 (N.=3), L1 (N.=9), L2 (N.=4), L3 (N.=3) and L4 (N.=1). RESULTS: The mean follow-up period was 60.9 months (50-75 months). The mean operative time was 77 min (range 55-135 min) and the bleeding was very low (<100 mL). VAS was significantly improved from 6.1 to 1.1 at last follow-up. Vertebral kyphosis decreased by 19° to 7.7° (ap<0.001) and local kyphosis was also significantly improved from 12.3° to 4.4° at last follow-up. We reported one screw misplacement that required early repositioning and 4 cement leakage, none of which was symptomatic. No patient worsened his neurological condition postoperatively. CONCLUSION: This treatment strategy is safe and effective. Clinical and radiological results seem to be stable over the time.

A retrospective case series of 103 consecutive patients with leptomeningeal metastasis and breast cancer.

Approximately 2-5 % of patients with breast cancer (BC) develop leptomeningeal metastasis (LM). 103 consecutive patients with BC were diagnosed with LM and initially treated with intra-CSF liposomal cytarabine from 2007 to 2011 at a single institution. Correlations were determined with respect to patient characteristics and BC subtype with regard to overall survival (OS). At LM diagnosis, 61 % of patients had a 0-2 performance status (PS), the remaining 39 % were severely neurologically impaired. Regardless of PS, all patients received intra-cerebrospinal fluid (CSF) liposomal cytarabine as first-line treatment. Systemic treatment and radiotherapy were also given in 58 and 17 % of patients respectively as clinically appropriate. Second- (intra-CSF thiotepa) and third-line (intra-CSF methotrexate) treatment was administered in 24 and 6 patients respectively. Median OS was 3.8 months (range 1 day-2.8 years). In multivariate analysis, an initial combined treatment, a second-line treatment with intra-CSF thiotepa, an initial clinical response, and a non-'ER/PR/HER2 negative' BC were significantly associated with a better OS. Median OS in this heterogeneous retrospective case series was similar to that of previously observed BC patients treated with intra-CSF methotrexate suggesting intra-CSF liposomal cytarabine is a reasonable first choice therapy of BC-related LM.

Recent concepts in the management of thoracolumbar spine metastasis.

As patient with cancer live longer, spine metastasis is a growing problem. Untreated, it can cause pain, instability and neurologic deficit, which can severely alter the patient's ability and quality of life. When the diagnosis is established, scoring systems help the physician to best define the objective of treatment by evaluating the life expectancy. Except in rare circumstances, treatment is palliative. Over the past 2 decades, remarkable evolution in surgical techniques provided to patients valuable therapeutic options to perform circumferential decompression and stabilization of the affected level. More recently, minimally invasive techniques allowed a significant reduction of morbidity. The parallel development of stereotactic radiosurgery offers new therapeutic options in particular for patients ineligible for surgery.

Minimally invasive surgery for intradural spinal meningioma: A new standard? A comparative study between minimally invasive and open approaches.

BACKGROUND: Some authors used minimally invasive surgery (MIS) in the treatment of spinal cord tumor, but these studies had a small sample sizes and mixed extra- and intra-medullary tumors, resulting in confounding biases. The objectives of the present study were to evaluate the effectiveness and safety of MIS for spinal meningioma resection in comparison with open surgery (OS). METHODS: Consecutive patients with spinal meningioma who received either MIS or OS were included. Data for extent of resection, functional outcome, postoperative morbidity and recurrence were collected. RESULTS: A total of 48 patients (with 51 spinal meningiomas) were included. Eighteen underwent MIS and 30 OS. Meningioma volume and location did not differ significantly between groups: tumors were predominantly thoracic (n=39, 76.5%) and voluminous (occupying more than 50% of the spinal canal: n=43, 84.3%). In the MIS group, patients were older (mean age: 66.5 vs. 56.4years, P=0.02) and more fragile (mean ASA score: 2.0 vs. 1.6, P=0.06). In the MIS group, the surgical procedure was shorter (mean duration: 2.07 vs. 2.56h, P=0.04), blood loss lower (mean: 252 vs. 456mL, P=0.02), and hospital stay shorter (mean: 6.6 vs. 8.1days). Surgery improved the modified McCormick scale (P<0.0001) irrespective of the surgical technique. MIS led to no significant differences in extent of resection or postoperative morbidity. Mean follow-up was 46.6 months. At last follow-up, 91.7% (n=44) of patients were free of progression; all cases of tumor progression (n=4) occurred in the OS group. CONCLUSIONS: MIS outperformed OS in the management of intradural spinal meningioma, irrespective of location and volume. MIS appears to be particularly suitable for elderly and fragile patients.

TSH-secreting adenoma improved with cabergoline.

TSH-secreting adenomas are rare tumors, representing only 0.5 to 2.5% of pituitary adenomas. Their main clinical characteristics include signs of thyrotoxicosis, diffuse goiter and a compressive syndrome. Biologically, free T4 and T3 serum levels are elevated, contrasting with inadequate serum TSH levels and increased alpha chains. Magnetic resonance (MR) imaging shows a pituitary tumor, the main differential diagnosis being resistance to thyroid hormones. Treatment is based on surgery, possibly associated with somatostatin analogs and radiotherapy. Though the long-term evolution of this rare pathology seems to have improved, some clinical situations are still a challenge to treat. We report one such case that was resistant to both stereotactic radiotherapy and somatostatin analogs, but surprisingly improved with cabergoline. We suggest that cabergoline should be considered as an alternative treatment in cases of pituitary adenomas that resist traditional treatments.

[Traumatic orbital encephalocele in an adult: report of one case]. / Encéphalocèle intraorbitaire post-traumatique chez un adulte: à propos d'un cas.

Orbital roof fractures after head injury is rare. Traumatic encephaloceles in the orbital cavity are even rarer, with only 24 cases published to date. We report the case of an adult with a post-traumatic orbital encephalocele. One day after a road traffic accident with head injury, the patient developed progressive pulsatile proptosis. Computed tomography and magnetic resonance imaging revealed an isolated blow-in fracture of the orbital roof with herniation of the left frontal lobe into the orbit. Neurosurgery to repair the orbital defect led to full recovery.

[Fracture luxation of the cervical spine in patients with ankylosing spondylitis: six cases]. / Fracture luxation du rachis cervical chez des patients atteints de spondylarthrite ankylosante: à propos de six cas.

BACKGROUND AND PURPOSE: Treatment of cervical spine fracture in patients with ankylosing spondylitis is difficult. Biomechanical changes related to ossified ankylosing spondylitis spine make cervical spine fractures highly unstable. They cover the entire width of the spine inducing multidirectional instability and the risk of neurological injuries. Treatment is more difficult that in the nonossified spine. Different treatments have been proposed including anterior stabilization, posterior stabilization, or both. METHODS: We reviewed retrospectively six cases of cervical fracture dislocation in patients with ankylosing spondylitis. RESULTS: There were five cases of C6C7 fracture dislocation and one case of C4C5 fracture dislocation. Four patients had neurological impairment at diagnosis. All patients underwent surgery. Two had anterior stabilization: one patient died and the other achieved bone healing. Four patients had anterior and posterior stabilization combined with a cervical brace for three months, for two and a halo cast for two, others because of persistent instability, with neurological injury in one. A neurological improvement was obtained in four patients. One patient was lost to follow-up. CONCLUSION: Surgical management of selected patients with ankylosing spondylitis and cervical spine fractures is challenging. Combined anterior and posterior stabilization should be considered for these fractures. A cervical brace must be associated with surgical treatment. With appropriate management, outcome can be favorable.

[Posterior extrusion of Biocompatible Orthopaedic Polymer (BOP) graft mimicking a calcified lumbar disc herniation: case report]. / Expulsion postérieure d'un greffon de Biocompatible orthopaedic polymer (BOP) mimant une hernie discale calcifiée lombaire: à propos d'un cas.

OBJECTIVE AND IMPORTANCE: We present a case of intracanalar extrusion of a L5S1 Biocompatible Orthopaedic Polymer (BOP) graft associated with a L4L5 disc herniation 19 years after a lumbar intersomatic fusion for a L5S1 disc herniation. Radiological aspect of this complication should be recognized by neurosurgeons. CLINICAL PRESENTATION: A 55-year old man presented with a right L5 sciatic pain. Neurological examination found a severe weakness in dorsal flexion of the foot. A lumbar CT scanner disclosed aspects consistent with right L4L5 and huge calcified L5S1 lumbar disc herniation. INTERVENTION: The patient was operated via a bilateral paravertebral approach and a L5 laminectomy. A dense and extensive epidural scarring was seen. The right L4L5 herniated disc was excised. At the left L5S1 level, fibres from a BOP graft had separated into large fragments extruded into the vertebral canal through the dura. The fibres could only be removed partially because of nerve roots adherence. The patient developed postoperative cerebrospinal fluid (CSF) leakage that required a second operation for dural closure. The postoperative course was uneventful and the patient recovered the right L5 root deficit. CONCLUSION: Neurosurgeons should be aware of the radiological aspect of this complication. If it is recognized on CT scan and asymptomatic, conservative management should be proposed because of the risk of nerve roots injury or postoperative CSF leakage.

Anterior lumbar sagittal alignment after anterior or lateral interbody fusion.

PURPOSE: Anterior or lateral interbody fusion is a treatment option for lumbar disc disease. A segmental change occurs after such surgery. This study was designed to evaluate the changes in the lumbar regional alignment after a single or two-level standalone anterior or lateral interbody fusion (ALIF or LLIF). METHODS: Data from patients referred to our institution between March 2013 and November 2015 for standalone ALIF or LLIF for low-grade isthmic spondylolisthesis or degenerative discopathy were retrospectively included in our analysis. Patients with a history of spinal fusion were excluded. Global and regional alignments were analyzed pre- and postoperatively. Pelvic tilt (PT), sacral slope (SS), sagittal vertical axis (SVA), lumbar lordosis (LL), index segmental lordosis (ISL) and L4S1 lordosis were compared. Three groups according to the pelvic incidence (PI) (low, normal and high) were separately analyzed then compared. RESULTS: Forty-one women and 27 men (mean age was 46 years; range 25-66) were included. The mean follow-up was 10.8 (range 3-34 months). The patients were globally well balanced preoperatively and remained after surgery (SVA stagnated from 16.76±28.42mm to 15.97±28.20mm, P=0.75). PT and LL did not vary. L4S1 lordosis, and ISL were significantly increased respectively from 30.56±8.59 to 34.58±7.47 (P=0.0026) and from 5.94±5.25 to 12.99±5.87 (P<0.0001) at latest follow-up. CONCLUSION: Despite effective changes in the segmental lordosis at the index levels, our findings suggest that one or two-levels standalone ALIF or LLIF had no effect on the global balance and the lumbar lordosis. The three groups behaved similarly, the regional lordosis was redistributed in a better harmony (L4S1/LL ratio went up from 55% to 61%, P=0.01). STUDY TYPE: Retrospective study. LEVEL OF EVIDENCE: 4.

[Primitive malignant melanoma arising in a spinal nerve root. A case report]. / Tumeur mélanocytaire primitive maligne radiculaire. A propos d'un cas.

We report the fourth case of primitive malignant melanoma arising in a spinal nerve root. A 39-year-old woman complained of one-year low back pain radiating to the right thigh and knee, and loss of 7 kg. Clinical examination found moderate quadricipital amyotrophy and hypoesthesia of anterior side of the thigh. MRI study demonstrated an enlargement of right L3 root with scalloping of the L3/L4 foramen. The T1-weighted MRI images showed a tumor hyperintensity, the T2-weighted images showed tumor isointensity and mild contrast enhancement. Due to the scalloping of L3/L4 foramen with root enlargement and slow evolution (more than one year between the first symptom and surgery without clinical worsening), the initial preoperative diagnosis was L3 schwannoma. After laminoarthrectomy and dural opening, a firm black lesion, well encapsulated and involved in a dorsal spinal root, was totally removed. The tumor was composed of irregular melanocytoid cells with high proliferation index (20%). Immunohistochemistry showed melanin, HMB-45 and S100 positivity, but reticulin was negative (that eliminates malignant melanocytic schwannoma). An extensive clinical and paraclinical research of other melanotic localisation was negative. So, the final diagnosis was intradural primitive malignant melanoma. Radiotherapy was performed on the site of the tumor. Fatal pulmonary metastasis occurred 18 months after surgery. The most common tumor with root enlargement and bony scalloping is the benign schwannoma. Despite the above described radiological features, MRI characteristics (hyperintensity when images are T1-weighted) suggest a melanocytic tumor, a tumor with a high adipose component or an intratumoral bleeding. Specific MRI sequences can eliminate adipose tissue tumor, but diagnosis between melanin and methemoglobin is still difficult. According to the index of proliferation, a primitive central melanocytic lesion can be a meningeal melanocytoma (considered as benign) or a primitive malignant melanoma. These tumors show identical protein expressions in immunohistochemistry, and their prognosis is very variable (some long-term remissions are reported for malignant melanomas and fast disseminations are described for meningeal melanocytomas treated by sub-total surgery). The L3/L4 foramen scalloping is unusual for a malignant lesion with theoretic high-speed development. The other 3 patients (reported in the literature) survive more than 3 years. The histological features of malignant lesion with benign clinical features lead to interrogation upon the actual pathologic classification.

Failed back surgery syndrome: to re-operate or not to re-operate? A retrospective review of patient selection and failures.

INTRODUCTION: Persisting pain after spine surgery remains a challenge for the patient and the pain physician. The etiology depends on age, pathology and the interval between the first and the revision surgery. In young patients who underwent initially to discectomy, the etiology of failed back surgery syndrome (FBSS) is commonly a recurrence of herniation whereas in the elderly population, who has previously undergone a spinal fusion, persisting pain might be due to secondary sagittal unbalance associated, as a consequence, to adjacent disc disease or pseudarthrosis. OBJECTIVE: To review the etiology of failed back surgery syndrome and to discuss the radiological work-up and the treatment strategies. METHODS: Retrospective analysis of 39 consecutive patients diagnosed with FBSS. For all cases, the following parameters were reviewed: original diagnosis and initial surgery, interval between the last surgery and the revision procedure, final diagnosis after revision. Treatment options were discussed. RESULTS: Twelve patients have undergone decompressive procedures and 27 had one or multilevel fusion for various back and/or leg pain. In group 1 (decompressive surgery), the mean age of patients who had a disc herniation was 42.2 years and 69 years for patients who had laminectomies for lumbar stenosis. In group 2 (fusion), the mean age was 63.3. Loss of lumbar lordosis in elderly after one or several laminectomy(ies) was found to be a cause of failure because of sagittal kyphosis and consecutive back pain. In the fused group, suboptimal correction of lumbar lordosis could generate a pseudarthrosis, proximal junctional kyphosis and persisting pain. CONCLUSION: Dealing with FBSS patients is far from simple but it corresponds to daily practice for spine surgeons. Clinical and radiological assessments should include a full diagnostic work-up focusing on sagittal balance. Surgical treatment and re-operation might be an option if a consistent source of pain is detected.

[Assessment of the surgeon radiation exposure during a minimally invasive TLIF: Comparison between fluoroscopy and O-arm system]. / Évaluation de l'exposition aux radiations du chirurgien lors d'un TLIF mini-invasif: comparaison entre fluoroscopie et navigation O-arm.

INTRODUCTION: Transforaminal lumbar interbody fusion with a minimally invasive approach (MIS TLIF) has become a very popular technique in the treatment of degenerative diseases of the lumbar spine, as it allows a decrease in muscle iatrogenic. However, iterative radiological controls inherent to this technique are responsible for a significant increase in exposure to ionizing radiation for the surgeon. New techniques for radiological guidance (O-arm navigation-assisted) would overcome this drawback, but this remains unproven. OBJECTIVES: To analyze the exposure of the surgeon to intraoperative X-ray during a MIS TLIF under fluoroscopy and under O-arm navigation-assisted. MATERIALS AND METHODS: This prospective study was conducted at the University Hospital of Lille from February to May 2013. Twelve patients underwent a MIS TLIF for the treatment of low-grade spondylolisthesis; six under standard fluoroscopy (group 1) and six under O-arm system (group 2). Passive dosimeters (rings and glasses) and active dosimeters for thorax were used to measure the radiation exposure of the surgeon. RESULTS: For group 1, the average time of fluoroscopy was 3.718 minutes (3.13-4.56) while no radioscopy was perform on group 2. For the first group, the average exposure dose was 12 µSv (5-20 µSv) on the thorax, 1168 µSv (510-2790 µSv) on the main hand and 179 µSv (103-486 µSv) on the lens. The exposure dose was measured zero on the second group. CONCLUSION: The maximum recommended doses can be reached, mainly for the lens. In addition to the radioprotection measures, O-arm navigation systems are safe alternatives to significantly reduce surgeon exposure.

Differential expression between PAX-6 and EN proteins in medulloblastoma.

A collection of 28 medulloblastomas was analyzed for expression of the developmental control genes PAX-6 and EN by immunohistochemical staining. Sixteen medulloblastomas expressed both EN and PAX-6 but, when differentiation could be assessed in the positive areas, PAX-6 is expressed in the less differentiated cells. Since Drosophila en encodes a negative regulator, we overexpressed the chicken en-1 in retinal pigmented epithelium cells. This resulted in Pax-6 down regulation. These results suggest a regulatory loop between PAX-6 and EN, two molecular markers of medulloblastoma.

Pronostic factors of synchronous brain metastases from lung cancer.

BACKGROUND: The prognosis of brain metastases (BM) from lung cancer is poor. The management of lung cancer with BM is not clear. This retrospective study attempts to determine their prognostic factors, and to better define the role of different treatments. METHODS: We reviewed the clinical characteristics of 271 consecutive patients with synchronous brain metastases (SBM) from lung cancer (small-cell lung cancers and non-small-cell lung cancers), collected between January 1985 and May 1993. Data were available for all patients as well as follow-up information on all patients through to death. Patients had all undergone heterogeneous treatments. Each physician had chosen the appropriate treatment after collegiate discussion. Survival curves were compared using the log-rank test in univariate analysis, and Cox's Regression model in multivariate analysis. Statistical significance was defined as P<0.05. RESULTS: 249 patients were assessable. Treatments included: neurosurgical resection in 56 cases, brain irradiation in 87 cases, and chemotherapy in 126 cases. Median overall survival time from the date of histological diagnosis of SBM was 103 days (range, 1-1699). In multivariate analysis, prognostic factors for longer overall survival times were: absence of adrenal metastases (P=0.007), neurosurgical resection (P=0.028), chemotherapy (P=0.032) and brain irradiation (P=0.008). Moreover, risk factors of intracranial hypertension as cause of death were number of SBM and absence of neurosurgical resection. CONCLUSIONS: These results and others suggest that patients with SBM from lung cancer be considered for carcinologic treatment, and not only for best supportive care. However, further studies are necessary to evaluate quality of life with or without carcinologic treatment.

False positive-false negative CT scan in late epileptic seizure: a meningioma-glioblastoma association.

A false-negative finding on initial CT is reported in a case of supratentorial glioma. This observation was peculiar because the first CT revealed a meningioma which might initially have been related to the clinical symptoms. The term false positive-false negative CT is proposed. The reasons for such CT failures are discussed. The accuracy of clues as to the localization of the glioma provided by EEG is emphasized.

Vertebrobasilar insufficiency resulting from traumatic atlantoaxial instability: case report.

Vertebrobasilar ischemia revealed atlantoaxial instability in a patient who had cervical spine trauma 2 years previously. Vertigo was elicited by rotation of the head to the right; angiography demonstrated the occlusion of the left vertebral artery in the same position. The patient recovered totally after surgical fusion of the atlantoaxial joint.

Intraventricular cavernomas: three cases and review of the literature.

OBJECTIVE AND IMPORTANCE: Cavernomas occur very rarely in the ventricular system. We report three cases of intraventricular cavernomas and review the literature. CLINICAL PRESENTATION: A 16-year-old female patient presented with a sudden distal deficit of the left superior limb. She had a voluminous tumor involving the two lateral ventricles, with radiological evidence of recent hemorrhage. A 30-year-old man presented with generalized seizures and a right hemiplegia related to a 4-cm-diameter cavernoma in the two lateral ventricles involving the interhemispheric scissure through the corpus callosum and left centrum ovale. The radiological appearance was not typical and did not allow the diagnosis. A 42-year-old man had a cavernoma in the third ventricle, which was responsible for his short-term memory loss. This cavernoma had been revealed by computed tomography that was performed after intracerebral hemorrhage related to another cavernoma in the right parietal lobe occurred. INTERVENTION: Stereotactic biopsies allowed the diagnosis of intraventricular cavernoma in the first case. Surgical removal via a right transcortical transventricular approach and a transcallosal approach in the first and second cases, respectively, was complete, resulting in good outcomes. Surgical removal via a right transcortical transventricular approach in the third case was partial. CONCLUSION: Intraventricular cavernomas are so uncommon that only 42 well-documented cases have been previously reported in the literature. It seems that their radiological diagnosis may be difficult because of their uncommon location in the ventricular system and their voluminous size. A wrong preoperative diagnosis has sometimes been the cause of inefficient therapy, such as radiotherapy, for these surgically curable benign lesions.

Intradural epidermoid cysts of the cerebellopontine angle: diagnosis and surgery.

We report on our recent experience with epidermoid cysts in the cerebellopontine angle. We operated on nine patients since 1985, seven of which were investigated with magnetic resonance imaging. Since the arrival of modern neuroimaging, large lesions can be found with only discrete symptoms, such as isolated tinnitus or unspecific headache. With computed tomography and magnetic resonance imaging, preoperative diagnosis was achieved for most patients; sometimes, however, epidermoid cysts may be very similar to arachnoid cysts. Surgery is the only possible treatment. The decision to operate should be carefully discussed for each patient, particularly if the patient is asymptomatic. The extent of the lesion at the anterior aspect of the brain stem, and sometimes above the tentorium cerebelli, fragile cortex, and vessels, and hazards of postoperative chemical meningitis often make such surgery difficult. The surgeon should not attempt total removal of the cyst membrane. Most patients who undergo surgery, however, recover well, with no or few sequelae. With a mean 3-year follow-up, no recurrence occurred, despite partial removal, as a result of the peculiarly slow growth of these lesions.

Control of tremor and involuntary movement disorders by chronic stereotactic stimulation of the ventral intermediate thalamic nucleus.

The authors report on the long-term results of chronic stereotactic stimulation of the ventralis intermedius thalamic nucleus performed in 14 cases of disabling and intractable tremor. There were 10 patients with parkinsonian tremor and four with essential tremor. Three of the 10 parkinsonian patients had previously undergone contralateral thalamotomy. Tremor was assessed by clinical evaluation, surface electromyography, accelerometer, and videotape recordings before and after stimulation. The deep-brain electrode was implanted in the ventralis intermedius nucleus according to stereotactic procedure and connected to a subcutaneous pulse generator after a stimulation test period. Tremor suppression or reduction was obtained in all cases with high-frequency (130 Hz) stimulation. Marked functional improvement was maintained in 11 patients with a mean follow-up interval of 17 months. Levodopa-induced dyskinesias observed in five parkinsonian patients prior to surgery were improved or suppressed in four cases by thalamic stimulation. Stimulation was continued during the day and stopped at night in eight cases. Six patients were stimulated night and day to avoid a rebound effect which appeared as soon as the pulse generator was stopped. The only side effects were hand tonic posture in one case and persistent paresthesia in another case. The mechanism of action of this attractive treatment may be a functional alteration of the thalamic discharging area. The authors conclude that this technique is a good alternative to thalamotomy, especially when the risks of high-frequency coagulation are severe in frail and older patients.

Image-guided endoscopic spine surgery: Part I. A feasibility study.

STUDY DESIGN: A feasibility study was performed to determine the efficacy of computer assistance in endoscopic spine surgery. OBJECTIVES: To assess a new method for computer assistance based on image guidance during thoracoscopic or any endoscopic spine procedure. To evaluate the reproducibility, the sensitivity and the reliability of the technique first in vitro and second in clinical use. SUMMARY OF BACKGROUND DATA: The computer-based, image-guided surgery is now a routine tool used in open spine surgery. Exposure of the anatomy of the vertebra is needed for registration. This methodology is inapplicable in endoscopic approach. Fluoroscopic-based navigation combines the technology of image-guided surgery and C-arm fluoroscopy. The navigation is based on the fluoroscopic images acquired before surgery. This technology is applicable to endoscopic surgery but the navigation is based on fluoroscopic image. The computed tomography images are not exploited. There are no published data on a technique that allows image-guided surgery based on computed tomography and magnetic resonance imaging. METHOD: A laboratory study was performed on a thoracic human spine. One vertebra was marked on the right lateral side of the body with five titanium marks. A percutaneous reference frame was specifically designed to be placed in the pedicle of the same marked vertebrae. The reference frame acted as a 3D localizer and a registration tool. The spine model was scanned including the reference frame. A standard Stealth station treatment guidance platform (Medtronic, Sofamor Danek, Memphis, TN) was used for simulation. The registration was obtained using the reference frame. Twenty navigation procedure trials were done and the error was recorded based on the distance between the anatomical point and the corresponding virtual one. RESULTS: Registration was always possible using the stealth station and a standard spine navigational software (spine 3, Medtronic Sofamor Danek, Memphis, TN). The mean error after registration given by the computer was 0.96 mm. The mean error recorded during the navigation simulation was 1.6 mm. CONCLUSIONS: This technique allows the possibility of computed tomography and magnetic resonance imaging-based, image-guided endoscopic surgery. It is probable that in the near future, as image fusion technology improves, the fluoronavigation based on fluoroscopic images would enable to navigate on multimodal images. Otherwise the technique described in this article is the only reproducible one that allows computed-tomography-based computer assistance during endoscopic procedures.