Impact of breath-hold level on positional error aligned by stent/Lipiodol in Hepatobiliary radiotherapy with breath-hold respiratory control.

BACKGROUND: Respiratory motion management with breath hold for patients with hepatobiliary cancers remain a challenge in the precise positioning for radiotherapy. We compared different image-guided alignment markers for estimating positional errors, and investigated the factors associated with positional errors under breath-hold control. METHODS: Spirometric motion management system (SDX) for breath holds was used in 44 patients with hepatobiliary tumor. Among them, 28 patients had a stent or embolized materials (lipiodol) as alignment markers. Cone-beam computed tomography (CBCT) and kV-orthogonal images were compared for accuracy between different alignment references. Breath-hold level (BHL) was practiced, and BHL variation (ΔBHL) was defined as the standard deviation in differences between actual BHLs and baseline BHL. Mean BHL, ΔBHL, and body-related factors were analyzed for the association with positional errors. RESULTS: Using the reference CBCT, the correlations of positional errors were significantly higher in those with stent/lipiodol than when the vertebral bone was used for alignment in three dimensions. Patients with mean BHL > 1.4 L were significantly taller (167.6 cm vs. 161.6 cm, p = 0.03) and heavier (67.1 kg vs. 57.4 kg, p = 0.02), and had different positional error in the craniocaudal direction (- 0.26 cm [caudally] vs. + 0.09 cm [cranially], p = 0.01) than those with mean BHL < 1.4 L. Positional errors were similar for patients with ΔBHL< 0.03 L and > 0.03 L. CONCLUSION: Under rigorous breath-hold respiratory control, BHL correlated with body weight and height. With more accurate alignment reference by stent/lipiodol, actual BHL but not breath-hold variation was associated with craniocaudal positional errors.

Sacral Neuromodulation: Standardized Electrode Placement Technique.

INTRODUCTION: Sacral neuromodulation (SNM) (sacral nerve stimulation SNS) has become an established therapy for functional disorders of the pelvic organs. Despite its overall success, the therapy fails in a proportion of patients. This may be partially due to inadequate electrode placement with suboptimal coupling of the electrode and nerve. Based on these assumptions the technique of sacral spinal neuromodulation has been redefined. All descriptions relate to the only currently available system licensed for all pelvic indications (Medtronic Interstim® ). METHOD: An international multidisciplinary working party of ten individuals highly experienced in performing SNM convened two meetings (including live operating) to standardize the implant procedure. This report addresses the main steps to optimal electrode lead placement in temporal sequence. RESULTS: Key elements of the electrode placement are radiological marking, the use of a curved stylet, the entry of the electrode into the sacral foramen and its progression through the foramen, its placement guided by a combination of a typical appearance in fluoroscopy and achieving specific motor/sensory responses with stimulation. The report describes quadripolar electrode placement and then either insertion of a connecting percutaneous extension lead or permanent implantation of the programmable device. CONCLUSION: Standardization of electrode placement may ensure close electrode proximity to the target nerve providing a higher likelihood for optimal effect with less energy consumption (better battery longevity), more programming options with more electrode contacts close to the nerve and reduced likelihood of side-effects. The potentially better clinical outcome needs to be demonstrated.

Comparative study of the efficacy of the canalith repositioning procedure versus the vertigo treatment and rehabilitation chair.

CONCLUSION: Vertigo treatment and rehabilitation chair (TRV) may be suggested as the first choice for patients with posterior canal benign paroxysmal positional vertigo (p-BPPV). OBJECTIVE: To investigate the short- and long-term treatment efficacy of the canalith repositioning procedure (CRP) versus TRV for patients with p-BPPV. METHODS: A total of 165 patients with unilateral p-BPPV were assigned to either the CRP group or the TRV group. Patients were assessed at 1 week, 4 weeks, 3 months, and 6 months after their first treatment. The numbers of treatment sessions required for successful repositioning in both groups at 4 weeks, 3 months, and 6 months were recorded. RESULTS: Treatment efficacy of patients in the TRV group was significantly better than that of patients in the CRP group 1 week after the first treatment. The number of treatment sessions needed for successful repositioning was significantly lower in the TRV group than in the CRP group at 4 weeks and 3 months after the first treatment.

Effectiveness of a breath-hold monitoring system in improving the reproducibility of different breath-hold positions in multiphasic CT imaging.

This study tests whether the utilization of an electronic breath-hold monitoring device improves breath-hold reproducibility during computed tomographic (CT) scanning. Two cohorts of 40 patients underwent dual-phase abdominal CT scans, either with a breath-hold monitoring device or with the standard breath-holding technique. Two blinded readers measured the differences in diaphragmatic position between phases. There was no statistical difference in diaphragmatic position (P=.14) between the monitored (8.5±11.5 mm) and control (5.6±5.2 mm) cohorts. Ten percent of patients from the monitored cohort had greater than 20 mm of deviation, versus 0%-2.5% for the control cohort. Reproduction of breath-holding position remains challenging, even with a monitoring system.

Guidelines for the placement of fiducial points in image-guided neurosurgery.

BACKGROUND: Point-pair registration is widely used to register the patient and the image space in image-guided neurosurgery. The registration accuracy at the target point is influenced by the distribution of the fiducial points, and it is not always easy to achieve a good distribution in clinical practice. METHODS: We propose one original configuration and three variants of the distribution of the fiducial points, in which each fiducial point has a definite position on the head surface. These configurations are conceived by considering both the theoretical value of the target registration error (TRE) and practical constraints on the positioning of the fiducial points. These configurations can guide the surgeon to place fiducial points directly onto the patient's head. RESULTS: Experiments with real clinical data showed that when using the original configuration, the TRE in the whole skull was < 2 mm and the TRE in the whole brain was < 1.5 mm if the fiducial registration error was 2.5 mm. When using variants of the original configuration, small TRE can also be achieved in the corresponding surgical field. CONCLUSIONS: This study provides an easy-to-use approach to achieving good distribution of fiducial points in image-guided neurosurgery.

Percutaneous approach to the upper thoracic spine: optimal patient positioning.

Percutaneous access to the upper thoracic vertebrae under fluoroscopic guidance is challenging. We describe our positioning technique facilitating optimal visualisation of the high thoracic vertebrae in the prone position. This allows safe practice of kyphoplasty, vertebroplasty and biopsy throughout the upper thoracic spine.