Olivier Hauger

MR imaging of intrarenal macrophage infiltration in an experimental model of nephrotic syndrome.

The objective of this study was to use MR imaging to detect macrophage infiltration of the kidney after injection of ultrasmall superparamagnetic iron oxide (USPIO) particles in a rat model of experimental nephropathy. Ninety μmol of USPIO were injected intravenously in 10 rats with nephropathy secondary to intravenous injection of 5 mg of puromycin aminonucleoside (PAN), and in 10 control rats. The signal intensity was measured in each kidney compartment before and 24 h after injection of the contrast agent. FLASH sequences were performed on a spectrometer operating at 4.7 T. MR findings were compared with histological data. Twenty‐four hours after injection of USPIO, a significant decrease (P < 0.0001) was observed in signal intensity in each kidney compartment in the PAN group. There was no variation in the control group. In the diseased kidneys, histological data revealed the presence of macrophages with iron oxide particles within their cytoplasm and lysosomes. Using USPIO, MR imaging can evidence infiltration of the rat kidney by macrophages. Magn Reson Med 41:156‐162, 1999.

Percutaneous Facet Screw Fixation of Lumbar Spine with CT and Fluoroscopic Guidance: A Feasibility Study

PURPOSE To assess the feasibility of computed tomography (CT)- and fluoroscopy-guided percutaneous facet screw fixation following anterior lumbar interbody fusion (ALIF) or anterior pseudarthrosis in adults. MATERIALS AND METHODS Institutional review board approval and informed consent were obtained for this study. One hundred seven consecutive adult patients (46 men, 61 women; mean age ± standard deviation: 56.3 years ± 12.9) with ALIF (n = 79) or anterior pseudarthrosis (n = 28) were prospectively treated by means of percutaneous facet screw fixation with CT and fluoroscopic guidance. Two 4.0-mm cannulated screws were placed per level to fix facet joints by using either a translaminar facet or transfacet pedicle pathway. Only local anesthesia was used during these procedures. Procedural time was noted for each patient. Postoperative follow-up ranging from 1 year to 3 years was assessed by using Macnab and radiologic criteria. RESULTS The mean procedure times for a lumbar single-level and a double-level fusion ranged from 15 to 25 minutes and from 40 to 50 minutes, respectively. All the transfacet pedicle (n = 182) and translaminar facet (n = 56) screws were successfully placed in one attempt. Radiographic fusion was observed within the year following posterior fixation in all patients despite one translaminar screw failure. According to the Macnab criteria, the clinical results were classified as excellent in 92 (86%) and good in 15 (14%) of 107 patients at the time of their last follow-up examination. CONCLUSION This feasibility study showed that CT- and fluoroscopy-guided percutaneous facet screw fixation is a rapid, safe, and effective method.

Foreign body extraction from soft tissue by using CT and fluoroscopic guidance: a new technique

We report on a new minimally invasive technique for the retrieval of a surgical pin fragment after accidental migration into the soft tissue of the shoulder in two patients. The technique is performed under local anaesthesia and uses combined CT and fluoroscopic guidance. The materials used were simple, combining a bone biopsy needle and an endoscopy clamp. Pin displacement was confirmed under fluoroscopic guidance and the clamp was used to withdraw the pin to the cutaneous entry point under CT (step-by-step) guidance. The CT slices provide perfect visualisation of the vascular or nervous structures as well as perfect positioning of the extremity of the trocar relative to the material to be removed. This intervention avoids a second surgical intervention with a longer incision and avoided repeated general anaesthesia.

Percutaneous discectomy on lumbar radiculopathy related to disk herniation: Why under CT guidance? An open study of 100 consecutive patients

The primary objective of this study conducted on 100 patients is to demonstrate that performing CT-guided percutaneous discectomy for herniated disks results in a significant improvement in pain symptoms at several times (D1, D2, D7, 1 month, 3 months, 6 months). This objective assesses the effectiveness and feasibility of this technique under CT guidance in patients presenting documented lower back pain related to disk herniation that has not improved with appropriate medical treatment. The impact of various factors on the effectiveness of discectomy will also be evaluated. At 1 week, we notes a decrease in average VAS respectively of 71% and 67% in patients treated for posterolateral and foraminal herniated disks; the result for posteromedian herniated disks is only 45% in average decrease. At 6 months post op, 79% of lateralized herniated disks have a satisfactory result (≥ 70% decrease in pain as compared to initial pain), whereas post median herniated disks had a satisfactory result in only 50% of cases. Percutaneous fine needle discectomy probe under combined CT and fluoroscopic guidance is a minimally invasive spine surgery which should be considered as an alternative to surgery. This technique presents several advantages: the small diameter of the probe used (maximum 16 G or 1.5mm) allows a cutaneous incision of only a few millimeters, and a trans-canal approach can be possible; it also decreases the risk of ligamentary lesion and does not cause an osseous lesion of the posterior arc or of the adjacent muscular structures.

Vertebral split fractures: technical feasibility of percutaneous vertebroplasty.

OBJECTIVE The treatment of vertebral split fractures remains controversial, consisting of either corset or internal fixation. The aim of this study was to evaluate the technical feasibility of CT- and fluoroscopy-guided percutaneous vertebroplasty in the treatment of vertebral split fractures. MATERIALS AND METHODS Institutional review board approval and informed consent were obtained for this study. Sixty-two consecutive adult patients who had post-traumatic vertebral split fractures (A2 according to the AO classification) without neurological symptoms were prospectively treated by percutaneous vertebroplasty. All these procedures were performed by an interventional radiologist under computed tomography (CT) and fluoroscopy guidance by using only local anaesthesia. Postoperative outcome was assessed using the visual analogue scale (VAS) and Oswestry disability index (ODI) scores. RESULTS Vertebroplasty was performed on thoracic and lumbar vertebrae, creating a cement bridge between the displaced fragment and the rest of the vertebral body. Seven discal cement leakages (11%) were observed, without occurrence of adjacent vertebral compression fractures. The mean VAS measurements ± standard deviation (SD) significantly decreased from 7.9 ± 1.5 preoperatively to 3.3 ± 2.1 at 1 day, 2.2 ± 2.0 at 1 month, and 1.8 ± 1.4 at 6 months (P<0.001). The mean ODI scores ± SD had also a significant improvement: 62.3 ± 17.2 preoperatively and 15.1 ± 6.0 at the 6-month follow-up (P<0.001). CONCLUSION This study suggests that type A2 vertebral fractures could be successfully treated by CT- and fluoroscopy-guided percutaneous vertebroplasty.

Percutaneous screw fixation of a vertebral pedicle fracture under CT-guidance: a new technique.

We report on a new minimally invasive technique for the vertebral pedicle fracture after placement of a prosthetic disc. This intervention is an adaptation of CT-guided sacroiliac and acetabular fracture screw fixation. This type of procedure enables the perfect placement and measurement of the screw, as well as an extremely small incision under local anesthesia. CT guided Transpedicular fixation could be a useful strategy in the treatment of future cases involving poorly healing pedicle fractures causing persistent symptoms. This intervention confirms the range of capacities of CT scan-controlled interventions in terms of precision, safety, speed, minimal invasiveness, rapid return to everyday activity and consequently, economical management.

An open-label, prospective, observational study of the efficacy of bisphosphonate therapy for painful osteoid osteoma

AbstractObjectivesTo assess the efficacy of bisphosphonate therapy on bone pain in patients with osteoid osteoma (OO) (main objective), and to describe bisphosphonate-induced changes in nidus mineralisation and regional bone-marrow oedema (BMO).MethodsA prospective, observational study was conducted from 2011 to 2014. Patients with risk factors for complications of percutaneous or surgical ablation or recurrence after ablation, were offered once monthly intravenous bisphosphonate treatment until significant pain alleviation was achieved.ResultsWe included 23 patients. The first two patients received pamidronate and the next 21 zoledronic acid (mean, 2.95 infusions per patient). Bisphosphonate therapy was successful in 19 patients (83%), whose mean pain visual analogue scale score decreased by 76.7%; this pain-relieving effect persisted in 17 patients (74%) with a mean follow-up time of 36 months. Computed tomography (CT) demonstrated a mean nidus density increase of 177.7% (p = 0.001). By magnetic resonance imaging (MRI), mean decreases were 38.4% for BMO surface area and 30.3% for signal intensity (p = 0.001 and p = 0.000, respectively).ConclusionsIn 17/23 patients with painful OO managed conservatively with bisphosphonates, long-term final success was achieved. Bisphosphonates may accelerate the spontaneous healing of OO.Key points• 19/23 patients with OO managed with bisphosphonates experienced significant pain relief • Pain relief was sustained in 17/23 patients, mean follow-up of 36 months • CT demonstrated a significant increase in nidus mineralisation • MRI demonstrated a significant decrease in bone marrow oedema • Bisphosphonate therapy may accelerate the spontaneous healing of OO

Sémiologie des métastases osseuses en radiologie conventionnelle

Bone metastases are detected at initial diagnosis of cancer in 25% of cases and bone metastases are common in the course of a majority of cancer types. The spine and proximal long bones are the most affected sites. Knowledge of the basic radiological semiology is important to make the proper diagnosis of metastasis(s) bone(s), especially in situations in which the clinical context is not suggestive of metastases (such as cases where bone metastases are inaugural or cases of peripheral solitary metastasis). Tumor aggressiveness can be assessed at the level of the cortical bone and periosteum. Lodwick criteria are useful for the diagnosis of malignancy and tumor aggressiveness at initial diagnosis on plain radiographs, which are very important in the context of bone metastases. A CT scanner is required to confirm the malignancy of a bone lesion. MRI is complementary to the scanner including for the assessment of bone marrow involvement and tumor extensions.

Sémiologie des métastases osseuses en radiologie conventionnelleImaging of bone metastases

Bone metastases are detected at initial diagnosis of cancer in 25% of cases and bone metastases are common in the course of a majority of cancer types. The spine and proximal long bones are the most affected sites. Knowledge of the basic radiological semiology is important to make the proper diagnosis of metastasis(s) bone(s), especially in situations in which the clinical context is not suggestive of metastases (such as cases where bone metastases are inaugural or cases of peripheral solitary metastasis). Tumor aggressiveness can be assessed at the level of the cortical bone and periosteum. Lodwick criteria are useful for the diagnosis of malignancy and tumor aggressiveness at initial diagnosis on plain radiographs, which are very important in the context of bone metastases. A CT scanner is required to confirm the malignancy of a bone lesion. MRI is complementary to the scanner including for the assessment of bone marrow involvement and tumor extensions.

Discoscanner : indication, technique, trucs et astuces, interpretation

Objectifs Connaitre les nouvelles indications des discoscanners du rachis. Savoir realiser l’examen en connaissant les criteres de positivite morphologique ou fonctionnel. Connaitre les attentes des neurochirurgiens et des chirurgiens orthopedistes. Points cles Les demandes de discoscanner sont de plus en plus frequentes. La discographie donne 2 types d’informations : l’analyse de l’anato-mie intra-discale en detectant la fissure annulaire et la morphologie du nucleus. L’analyse fonctionnelle de la pression ou du volume intra-discal est necessaire a la reproduction de la douleur. Resume Les nouvelles interventions rachidiennes comme la mise en place de prothese discale imposent une exploration fonctionnelle du rachis que seule la discographie provocative et morphologique peut renseigner. Le discanner est un examen invasif dont l’indication doit etre posee avec precaution et en consultation multidisciplinaire. Cette exploration trouve sa place dans les lombalgies ou lomboradiculalgies peu documentees par l’IRM et dont la correlation radio-clinique n’est pas satisfaisante. C’est le seul examen permettant une analyse fonctionnelle du disque qui permet de detecter le veritable etage discal pathogene.