Peri-operative brachial plexus injury following self-positioning for stereotactic radiofrequency ablation.

A 71-year-old woman with a known accessory cervical rib and distinct scoliosis was scheduled for elective, percutaneous stereotactic radiofrequency ablation of a non-resectable intrahepatic cholangiocellular carcinoma. Patient positioning and fixation using a Bluebag fixation system (Medical Intelligence, Schwabmünchen, Germany) and a dedicated adjustable armrest were customised in the patient while awake. In order to provide safe conditions for mask ventilation and tracheal intubation, the patient was returned to standard supine positioning without changing the position of the armrest. Following the induction of general anaesthesia, the patient's arm was returned to the previously defined position. Upon completion of the procedure and emergence from anaesthesia, the patient immediately reported symptoms of severe brachial plexus damage. Therefore, we suggest that awake positioning according to current recommendations does not completely preclude the possibility of neurologic injury.

Integrating interventional oncology in the treatment of liver tumors.

BACKGROUND: Percutaneous ablation techniques offer a vast armamentarium for local, minimally invasive treatment of liver tumors, nowadays representing an established therapeutic option, which is integrated in treatment algorithms, especially for non-resectable liver tumors. The results of ablative treatment compare very well to surgical treatment in liver lesions, and confirm that these techniques are a valuable option for bridging for transplantation. Different techniques have been established to perform tumor ablation, and the feasibility varies according to the procedure and technical skills of the operator, depending on the size and location of the liver lesion. In recent years, stereotactic multi-needle techniques using 3D trajectory planning, general anesthesia, and tube disconnection during needle placement have had a strong impact on the application range of ablation for liver tumors. CONCLUSION: It is well known that creating a sufficient ablation margin and overlapping ablation zones is one key issue to enable ablation of large liver lesions with tumor-free margins (A0 ablation in analogy to R0 resection). Image fusion during treatment and follow-up assure highly accurate staging procedures and interventional planning. NOVEL ASPECTS: Review on the standards in ablation techniques for the treatment of liver tumors. Update on different ablation techniques, indications, and contraindications for percutaneous liver tumor treatment. Summary of recently published reports on liver tumor ablation.

A rare case of Epstein-Barr virus-associated hepatosplenic smooth muscle tumors after kidney transplantation.

A 27-year old caucasian male was diagnosed 2.7 years after kidney transplantation with Epstein-Barr virus (EBV)-associated smooth muscle tumors in liver and spleen. The reduction in immunosuppression and conversion from tacrolimus to sirolimus did not lead to a regression of the tumors. Additionally, the patient developed a cellular rejection of his renal allograft, which was successfully treated. A combined approach with stereotactic radiofrequency ablation (SRFA) and surgical resection was effective in the treatment of the tumors.

Use of flexible elbow reamers for cement removal in the humerus during revision shoulder arthroplasty.

Humeral cement removal in revision shoulder arthroplasty can be challenging. Secondary damage to the bone and neighbouring structures can be extensive and compromise later reconstruction. We present a technique that employs flexible reamers from elbow arthroplasty instrumentation, which aids cement removal at the same time as minimizing the risk of iatrogenic injury.

Ten questions on prosthetic shoulder infection.

Prosthetic shoulder infection can cause significant morbidity secondary to pain and stiffness. Symptoms may be present for years before diagnosis because clinical signs are often absent and inflammatory markers may be normal. An emerging common culprit, Propionibacterium acnes, is hard to culture and so prolonged incubation is necessary. A negative culture result does not always exclude infection and new synovial fluid biochemical markers such as α defensin are less sensitive than for lower limb arthroplasty. A structured approach is necessary when assessing patients for prosthetic shoulder joint infection. This includes history, examination, serum inflammatory markers, plain radiology and aspiration and/or biopsy. A classification for the likelihood of prosthetic shoulder infection has been described based on culture, pre-operative and intra-operative findings. Treatment options include antibiotic suppression, debridement with component retention, one-stage revision, two-stage revision and excision arthroplasty. Revision arthroplasty is associated with the best outcomes.

Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study.

PURPOSE: We compared the targeting accuracy and reliability of two different electromagnetic navigation systems for manually guided punctures in a phantom. MATERIALS AND METHODS: CT data sets of a gelatin filled plexiglass phantom were acquired with 1, 3, and 5 mm slice thickness. After paired-point registration of the phantom, a total of 480 navigated stereotactic needle insertions were performed manually using electromagnetic guidance with two different navigation systems (Medtronic Stealth Station: AxiEM; Philips: PercuNav). A control CT was obtained to measure the target positioning error between the planned and actual needle trajectory. RESULTS: Using the Philips PercuNav, the accomplished Euclidean distances were 4.42 ±â€Š1.33 mm, 4.26 ±â€Š1.32 mm, and 4.46 ±â€Š1.56 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.84 ±â€Š1.59 mm, 3.84 ±â€Š1.43 mm, and 3.81 ±â€Š1.71 mm, respectively. Using the Medtronic Stealth Station AxiEM, the Euclidean distances were 3.86 ±â€Š2.28 mm, 3.74 ±â€Š2.1 mm, and 4.81 ±â€Š2.07 mm at a slice thickness of 1, 3, and 5 mm, respectively. The mean lateral positional errors were 3.29 ±â€Š1.52 mm, 3.16 ±â€Š1.52 mm, and 3.93 ±â€Š1.68 mm, respectively. CONCLUSION: Both electromagnetic navigation devices showed excellent results regarding puncture accuracy in a phantom model. The Medtronic Stealth Station AxiEM provided more accurate results in comparison to the Philips PercuNav for CT with 3 mm slice thickness. One potential benefit of electromagnetic navigation devices is the absence of visual contact between the instrument and the sensor system. Due to possible interference with metal objects, incorrect position sensing may occur. In contrast to the phantom study, patient movement including respiration has to be compensated for in the clinical setting. KEY POINTS: • Commercially available electromagnetic navigation systems have the potential to improve the therapeutic range for CT guided percutaneous procedures by comparing the needle placement accuracy on the basis of planning CT data sets with different slice thickness. Citation Format: • Putzer D, Arco D, Schamberger B et al. Comparison of Two Electromagnetic Navigation Systems For CT-Guided Punctures: A Phantom Study. Fortschr Röntgenstr 2016; 188: 470 - 478.

[Ganglion block. When and how?]. / Ganglienblockade. Wann und wie?

CLINICAL ISSUE: Increasing understanding of the anatomy and physiology of neural structures has led to the development of surgical and percutaneous neurodestructive methods in order to target and destroy various components of afferent nociceptive pathways. The dorsal root ganglia and in particular the ganglia of the autonomous nervous system are targets for radiological interventions. The autonomous nervous system is responsible for the regulation of organ functions, sweating, visceral and blood vessel-associated pain. STANDARD RADIOLOGICAL METHODS: Ganglia of the sympathetic chain and non-myelinized autonomous nerves can be irreversibly destroyed by chemical and thermal ablation. PERFORMANCE: Computed tomography (CT)-guided sympathetic nerve blocks are well established interventional radiological procedures which lead to vasodilatation, reduction of sweating and reduction of pain associated with the autonomous nervous system. ACHIEVEMENTS AND PRACTICAL RECOMMENDATIONS: Sympathetic blocks are applied for the treatment of various vascular diseases including critical limb ischemia. Other indications for thoracic and lumbar sympathectomy include complex regional pain syndrome (CRPS), chronic tumor associated pain and hyperhidrosis. Neurolysis of the celiac plexus is an effective palliative pain treatment particularly in patients suffering from pancreatic cancer. Percutaneous dorsal root ganglion rhizotomy can be performed in selected patients with radicular pain that is resistant to conventional pharmacological and interventional treatment.

Ultralow-dose computed tomography imaging for surgery of midfacial and orbital fractures using ASIR and MBIR.

The influence of dose reductions on diagnostic quality using a series of high-resolution ultralow-dose computed tomography (CT) scans for computer-assisted planning and surgery including the most recent iterative reconstruction algorithms was evaluated and compared with the fracture detectability of a standard cranial emergency protocol. A human cadaver head including the mandible was artificially prepared with midfacial and orbital fractures and scanned using a 64-multislice CT scanner. The CT dose index volume (CTDIvol) and effective doses were calculated using application software. Noise was evaluated as the standard deviation in Hounsfield units within an identical region of interest in the posterior fossa. Diagnostic quality was assessed by consensus reading of a craniomaxillofacial surgeon and radiologist. Compared with the emergency protocol at CTDIvol 35.3 mGy and effective dose 3.6 mSv, low-dose protocols down to CTDIvol 1.0 mGy and 0.1 mSv (97% dose reduction) may be sufficient for the diagnosis of dislocated craniofacial fractures. Non-dislocated fractures may be detected at CTDIvol 2.6 mGy and 0.3 mSv (93% dose reduction). Adaptive statistical iterative reconstruction (ASIR) 50 and 100 reduced average noise by 30% and 56%, and model-based iterative reconstruction (MBIR) by 93%. However, the detection rate of fractures could not be improved due to smoothing effects.

Comparison of freehand-navigated and aiming device-navigated targeting of liver lesions.

BACKGROUND: Accurate needle placement is crucial for the success of percutaneous radiological needle interventions. We compared three guiding methods using an optical-based navigation system: freehand, using a stereotactic aiming device and active depth control, and using a stereotactic aiming device and passive depth control. METHODS: For each method, 25 punctures were performed on a non-rigid phantom. Five 1 mm metal screws were used as targets. Time requirements were recorded, and target positioning errors (TPE) were measured on control scans as the distance between needle tip and target. RESULTS: Time requirements were reduced using the aiming device and passive depth control. The Euclidian TPE was similar for each method (4.6 ± 1.2-4.9 ± 1.7 mm). However, the lateral component was significantly lower when an aiming device was used (2.3 ± 1.3-2.8 ± 1.6 mm with an aiming device vs 4.2 ± 2.0 mm without). DISCUSSION: Using an aiming device may increase the lateral accuracy of navigated needle insertion.

Ultrasound guided versus CT-controlled pararadicular injections in the lumbar spine: a prospective randomized clinical trial.

BACKGROUND AND PURPOSE: Injection therapies play a major role in the treatment of lower back pain and are to date performed mainly under CT- or fluoroscopic guidance. We conducted this study to evaluate the accuracy, time savings, radiation doses, and pain relief of US-guided pararadicular injections versus CT-controlled interventions in the lumbar spine in a prospective randomized clinical trial. MATERIALS AND METHODS: Forty adult patients were consecutively enrolled and assigned to a US or CT group. US-guided pararadicular injections were performed on a standard US device by using a broadband curved-array transducer (9-4 or 5-1 MHz). In the in-plane technique, the needle was advanced through the respective segmental intertransverse ligament. The needle tip position was verified by CT. The CT-guided approaches were performed under standardized procedures by using the CT-positioning laser function. RESULTS: The accuracy of US-guided interventions was 90%. The mean time to final needle placement in the US group was 4.0 ± 1.8 minutes, and in the CT group, 7.6 ± 2.1 minutes. The mean radiation doses, including CT confirmation for study purposes only, were 20.3 ± 9.0 mGy cm for the US group and 42.6 ± 36.1 mGy cm for the CT group. Both groups showed the same significant pain relief (P < .05) without relevant "intermethodic" differences of pain relief (P > .05). CONCLUSIONS: US-guided pararadicular injections show a therapeutic effect similar to that in the time-consuming, expensive, ionizing CT or fluoroscopically guided pararadicular injections and result in a significant reduction of procedure time expenditure and avoidance of radiation.

Diagnostic value of software-based image fusion of computed tomography and F18-FDG PET scans in patients with malignant lymphoma.

AIM: The purpose of this study was to evaluate the accuracy of 2-deoxy-2-[fluorine-18]fluoro-D-glucose (FDG) positron emission tomography (PET), computed tomography (CT), and software-based image fusion of both modalities in the imaging of non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD). METHODS: 77 patients with NHL (n = 58) or HD (n = 19) underwent a FDG PET scan, a contrast-enhanced CT, and a subsequent digital image fusion during initial staging or followup. 109 examinations of each modality were evaluated and compared to each other. Conventional staging procedures, other imaging techniques, laboratory screening, and follow-up data constituted the reference standard for comparison with image fusion. Sensitivity and specificity were calculated for CT and PET separately. RESULTS: Sensitivity and specificity for detecting malignant lymphoma were 90% and 76% for CT and 94% and 91% for PET, respectively. A lymph node region-based analysis (comprising 14 defined anatomical regions) revealed a sensitivity of 81% and a specificity of 97% for CT and 96% and 99% for FDG PET, respectively. Only three of 109 image fusion findings needed further evaluation (false positive). CONCLUSION: Digital fusion of PET and CT improves the accuracy of staging, restaging, and therapy monitoring in patients with malignant lymphoma and may reduce the need for invasive diagnostic procedures.

[Stereotaxy and robotics for ablation - toy or tool?]. / Stereotaxie und Robotik zur Ablation - Spielzeug oder Werkzeug?

CLINICAL AND METHODOLOGICAL ISSUES: Ablative technologies allow local curative tumor treatment by thermal tissue damage. An important prerequisite is the coverage of all tumor cells. Tumor size is the most important limiting factor. STANDARD RADIOLOGICAL METHODS: The drawbacks of conventional computed tomography/ultrasound/magnetic resonance imaging (CT/US/MRI) guided radiofrequency ablation (RFA) are the absence of planning software, imprecise probe placement, imprecise control of probe placement and the ablation zone as well as the lack of reliability and reproducibility. METHODOLOGICAL INNOVATIONS: Stereotactic and robot-assisted systems allow planning of multiple probe positions based on CT/MRI and positron emission tomography (PET) planning data. The probes can be precisely placed according to the coordinates of the image datasets. PERFORMANCE: The 1 and 3 year survival rates after stereotactic RFA (SRFA) of cholangiocellular carcinoma were 91% and 70% respectively and the median overall survival was 60 months. After SRFA of 189 colorectal liver metastases in 63 patients there was no significant difference in local recurrence rates between tumors < 3 cm (17.7%), 3-5 cm (11.1%) and > 5 cm (17.4%). The median overall survival was 33.2 months and the 1, 3, and 5 year overall survival rates after SRFA in patients with resectable colorectal cancer were 92%, 66% and 48%, respectively. ACHIEVEMENTS: In our opinion the excellent and, to a large extent user-independent results justify the increased efforts in time and costs especially for the treatment of patients with large and irregular tumors. PRACTICAL RECOMMENDATIONS: Stereotaxy and robotics are valuable tools for effective tumor ablation especially of large tumors and are likely to gain in importance in the next few years.

Substantial dose reduction in modern multi-slice spiral computed tomography (MSCT)-guided craniofacial and skull base surgery.

PURPOSE: Reduction of the radiation exposure involved in image-guided craniofacial and skull base surgery is an important goal. The purpose was to evaluate the influence of low-dose protocols in modern multi-slice spiral computed tomography (MSCT) on target registration errors (TREs). MATERIALS AND METHODS: An anthropomorphic skull phantom with target markers at the craniofacial bone and the anterior skull base was scanned in Sensation Open (40-slice), LightSpeed VCT (64-slice) and Definition Flash (128-slice). Identical baseline protocols (BP) at 120  kV/100  mAs were compared to the following low-dose protocols (LD) in care dose/dose modulation: (LD-I) 100  kV/35ref. mAs, (LD-II) 80  kV/40 - 41ref. mAs, and (LD-III) 80  kV/15 - 17ref. mAs. CTDIvol and DLP were obtained. TREs using an optical navigation system were calculated for all scanners and protocols. Results were statistically analyzed in SPSS and compared for significant differences (p ≤ 0.05). RESULTS: CTDIvol for the Sensation Open/LightSpeed VCT/Definition Flash showed: (BP) 22.24 /32.48 /14.32 mGy; (LD-I) 4.61 /3.52 /1.62 mGy; (LD-II) 3.15 /2.01 /0.87 mGy; and (LD-III) na/0.76 /0.76 mGy. Differences between the BfS (Bundesamt für Strahlenschutz) reference CTDIvol of 9 mGy and the lowest CTDIvol were approximately 3-fold for Sensation Open, and 12-fold for the LightSpeed VCT and Definition Flash. A total of 33 registrations and 297 TRE measurements were performed. In all MSCT scanners, the TREs did not significantly differ between the low-dose and the baseline protocols. CONCLUSION: Low-dose protocols in modern MSCT provided substantial dose reductions without significant influence on TRE and should be strongly considered in image-guided surgery.

Navigated open, laparoscopic, and percutaneous liver surgery.

Resection and thermal ablation procedures are frequently used for the treatment of primary and secondary liver tumors. Various tools for the virtual planning of liver resections and ablation are available and some of them are already used clinically. Resection planes and ablation volumes can be optimized for sufficient safety margins while preserving a maximal amount of functional liver tissue. Connecting the pre-operative planning with intraoperative guidance based on the 3D imaging data would be desirable. Interactive image guided surgery enables visualization of the actual spatial location of the surgical instrument on preoperatively acquired images in real time. However, extensive soft tissue deformations during open and laparoscopic surgical and ablative procedures may occur, causing unacceptable inaccuracies. The current focus of research is the adaptation of the preoperative virtual planning models to surgery by using intraoperative imaging and biomechanical models. In contrast to open and laparoscopic surgical procedures percutaneous punctures can be performed with high accuracy under stereotactic conditions. Important prerequisites include patient immobilization, respiratory triggering and intraoperative imaging. Due to the high accuracy of probe positioning the virtual preoperative ablation plan can be precisely transferred into the real patient. A total of 350 patients with primary and secondary liver tumors have already successfully been treated with stereotactic radiofrequency ablation (SRFA). Due to its low complication rates and similar local recurrence and survival rates as compared to conventional surgery SRFA is an attractive alternative for the treatment for primary and secondary liver tumors.

[Magnetic resonance imaging of radiofrequency current-induced coagulation zones in the ex vivo bovine liver]. / Magnetresonanztomografie von durch Radiofrequenzablation erzeugten Koagulationszonen in der Ex-vivo-Rinderleber.

PURPOSE: To compare different magnetic resonance imaging sequences for correct representation and discrimination between non-ablated, partially ablated, and completely ablated tissue after radiofrequency ablation (RFA) in the ex vivo, non-perfused bovine liver model. MRI is the method of choice for imaging of the induced coagulation zones ex vivo. However, the optimal imaging sequence has not been determined yet. MATERIALS AND METHODS: RFA, which is a method to locally destroy malignant cells with heat and which has been established for the treatment of non-resectable liver tumors, was applied to bovine livers. After the RF ablation procedure, the livers were sliced for visual inspection of the coagulation zones. As a result, non-ablated, partially ablated, and completely ablated tissues were distinguished. For the subsequent MR imaging, markers were used to indicate the borders of the different zones. For every imaging sequence the tissue representation at the site of these markers was classified as "exact", "overestimating", "underestimating" and "not determinable". Additionally, T 1, T 2, and proton density (PD) maps were measured. RESULTS: It was found that both T 1 and T 2 values gradually decrease from non-ablated to ablated tissue, with T 1 showing a stronger relative change compared to T 2. For PD no change was observed between non-ablated and partially ablated tissue and a clear decrease was detected for the completely ablated zone. CONCLUSION: Sequences with a strong PD influence resulted in the highest accuracy for discrimination between completely ablated and partially ablated tissue. The differences in image quality and contrast could be explained by the observed T 1, T 2 and PD changes.

Preliminary experience with (68)Ga-DOTA-lanreotide positron emission tomography.

AIM: Positron emission tomography (PET) of (68)Ga-radiolabelled (SST) somatostatin receptor (R) binding peptides has recently been evaluated in SSTR positive tumor patients. First promising results in lung and thyroid tumor patients with (111)In-DOTA-Lanreotide (DOTA-LAN) scintigraphy have been described. We report our first experience with (68)Ga-labeled DOTA-LAN. METHODS: Eleven patients (3 non small cell lung cancer [NSCLC], 3 small cell lung cancer [SCLC], 3 radioiodine negative thyroid cancer, 2 medullary thyroid cancer [MTC]) were investigated. After intravenous injection of 75-150 MBq (68)Ga-DOTA-LAN dynamic studies were acquired over the tumor site for the first 40 min with a dedicated PET scanner in 3 patients, and 2 partial body scans were acquired at 20 and 50 min p.i. in 2 patients. Whole body acquisitions at 90 min after injection were acquired in all 11 patients. Image reconstruction was performed by iterative reconstruction utilizing additional transmission scans for attenuation correction. Vital parameters were recorded during the PET study and up to 24 h p.i. Blood and urinary sampling was done up to 4 hr after tracer injection in 8 patients. PET results were compared to conventional imaging techniques (CIT), i.e. computed tomography (CT) and/or magnetic resonance imaging (MRI). In 5 patients, (68)Ga-DOTA-LAN was compared with 2-[(18)F]fluoro-2-deoxy-D-glucose ((18)F-FDG). RESULTS: After intravenous (i.v.) injection of (68)Ga-DOTA-LAN the radioactivity in the blood rapidly decreased to less then 20% of the injected dose (ID) within the first 20 min and further decreased to less than 9% ID after 4 h. A cumulative urinary excretion of (68)Ga-DOTA-LAN up to 29.2 + or - 13.2% ID at 4 h was found. No acute side effects were observed. Tumor sites were visualized already during the first min after injection. Comparison of positron emission tomography (PET) and CIT showed concordant results in 3/8 patients and partial concordant results in 5/8 patients with matched results for the primary/recurrent tumor, mediastinal lymph nodes, or adrenal gland metastases. Partial concordant results were seen for the lung, bone, liver and cervical lymph node metastases. Micronodular metastases of the lung and the cerebrum were not visualized by (68)Ga-DOTA-LAN PET. The maximal standardized uptake values of the lung and bone tumor lesions ranged from 6 to 8 g/ml at 90 min p.i.. CONCLUSIONS: (68)Ga-DOTA-LAN visualized the majority of tumor lesions. Further studies are required to assess the clinical value, and to obtain the best imaging protocol of this new PET SSTR tracer.

Integration of multimodality imaging and surgical navigation in the management of patients with refractory epilepsy. A pilot study using a new minimally invasive reference and head-fixation system.

OBJECTIVE: To review the experience with a new system (VBH system) for minimally invasive frameless stereotactic guidance, acting as a common platform to provide multimodal image integration and surgical navigation in a consecutive series of 25 patients who underwent surgery for drug-resistant seizures. METHODS: The usefulness of the VBH system for integrating all images to produce one dataset and for intraoperative instrument guidance and navigation was judged semiquantitatively in a three-tiered scale (+, ++, +++). Seizure outcome was classified according to Engel. RESULTS: The presurgical evaluation extended over 21.2 months (mean). A total of 141 registrations of images were performed (mean 5.6 per patient, range: 2 to 16). In 19 (76%) of 25 patients structural data fused with functional data were used for the presurgical workup. Six patients proceeded directly to navigated resection. Nineteen patients (76%) underwent invasive recording, of whom 13 underwent resective surgery. In seven patients (28%) the combination of multimodal image fusion and intra-operative stereotactic guidance was judged "essential" (+++) to remove the epileptogenic zone. Integration of all images to form one dataset was "essential" (+++) for decision making in 15 and "helpful" (++) in 4 patients (overall 76% of patients). Intraoperative use of frameless neuronavigation was "essential" (+++) in ten and "helpful" (++) in all remaining patients. Eighty percent of the patients achieved satisfactory seizure outcome after 1 year. CONCLUSION: The VBH system is a safe and effective non-invasive tool for repetitive imaging, multimodal image fusion and frameless stereotactic surgical navigation in candidates for epilepsy surgery.

Flexibility of head positioning and head fixation provided by a novel system for non-invasive maxillary fixation and frameless stereotaxy: technical note.

OBJECTIVE: The aim of this study was to demonstrate the flexibility in patient positioning and head fixation provided by a newly developed, minimally invasive upper jaw fixation device in combination with standard navigation software. TECHNIQUE: The Vogele-Bale-Hohner (VBH) headholder and the Stereotactic Intervention and Planning Laboratory (SIP-Lab) Innsbruck reference frame, were applied in epilepsy surgery requiring stereotactic guidance. The system can be adapted to various positioning and instrument guidance requirements. Instrument holders can be fixed either to a base plate or directly to the mouthpiece. When used together with a head clamp and a stabilizing arm, there are no restrictions on patient positioning. When used with the non-invasive headholder, only the supine position is well-suited for use with the described guidance instrumentation. The system can also be used with the head placed on the horseshoe headholder without altering navigation support. CONCLUSION: The VBH mouthpiece combined with an external registration frame is a flexible tool that permits patient positioning and neuronavigation with the head either fixed with a head clamp, or restrained non-invasively with a headholder, or not fixed at all. This might be advantageous within the context of epilepsy surgery.

Development of a combined pyro- and hydro-metallurgical route to treat spent zinc-carbon batteries.

The potential of solvent extraction using Cynanex272 for the recovery of zinc from spent zinc carbon batteries after a prior leaching in hydrochloric acid has been investigated. The elemental analysis of the spent material was carried out by ICP-MS. The major metallic elements are: ZnO (41.30%), Fe(2)O(3) (4.38%), MnO(2) (2.69%), Al(2)O(3) (1.01%), CaO (0.36%) and PbO (0.11%). The quantitative leaching by hydrochloric acid showed that the dissolution rates are significantly influenced by temperature and concentration of the acid solutions. The experimental data for the dissolution rates have been analyzed and were found to follow the shrinking core model for mixed control reaction with surface chemical reaction as the rate-determining step. About 90.3% dissolution was achieved with 4M HCl solution at 80 degrees C with 0.050-0.063 mm particle size within 120 min at 360 rpm. Activation energy value of 22.78 kJ/mol and a reaction order of 0.74 with respect to H(+) ion concentration were obtained for the dissolution process. An extraction yield of 94.23% zinc by 0.032M Cyanex272 in kerosene was obtained from initial 10 g/L spent battery leach liquor at 25+/-2 degrees C and at optimal stirring time of 25 min. Iron has been effectively separated by precipitation prior to extraction using ammoniacal solution at pH 3.5, while lead and other trace elements were firstly separated from Zn and Fe by cementation prior to iron removal and zinc extraction. Finally, the stripping study showed that 0.1M HCl led to the stripping of about 95% of zinc from the organic phase.