Laparoscopic computer-navigated ablation of liver metastases

Objective In order to benefit from the obvious advantages of minimally invasive liver surgery there is a need to develop high precision tools for intraoperative anatomical orientation, navigation and safety control. In a pilot study we adapted a newly developed system for computer-assisted liver surgery (CALS) in terms of accuracy and technical feasibility to the specific requirements of laparoscopy. Here, we present practical aspects related to laparoscopic computer assisted liver surgery (LCALS). Methods Our video relates to a patient presenting with 3 colorectal liver metastases in Seg. II, III and IVa who was selected in an appropriate oncological setting for LCALS using the CAScination system combined with 3D MEVIS reconstruction. After minimal laparoscopic mobilization of the liver, a 4- landmark registration method was applied to enable navigation. Placement of microwave needles was performed using the targeting module of the navigation system and correct needle positioning was confirmed by intraoperative sonography. Ablation of each lesion was carried out by application of microwave energy at 100 Watts for 1 minute. Results To acquire an accurate (less 0.5 cm) registration, 4 registration cycles were necessary. In total, seven minutes were required to accomplish precise registration. Successful ablation with complete response in all treated areas was assessed by intraoperative sonography and confirmed by postoperative CT scan. Conclusions This teaching video demonstrates the theoretical and practical key points of LCALS with a special emphasis on preoperative planning, intraoperative registration and accuracy testing by laparoscopic methodology. In contrast to mere ultrasound-guided ablation of liver lesions, LCALS offers a more dimensional targeting and higher safety control. This is currently also in routine use to treat vanishing lesions and other difficult to target focal lesions within the liver.

Endoscopic ultrasonography for the diagnosis of intrathoracic lesions in two dogs.

Endoscopic ultrasound was developed initially in humans to overcome limitations of conventional ultrasound in examining certain internal organs due to intervening bone or air-filled structures. Endoscopic ultrasound has been used most widely in investigation of the gastrointestinal tract in humans, but many intrathoracic applications as well as endoscopic ultrasound-guided techniques have recently been described. Mediastinal and pulmonary structures can be examined with endoscopic ultrasound since a high frequency ultrasound probe can be brought into close contact with the areas of interest via a transesophageal approach. The purpose of this report is to describe the application of endoscopic ultrasound as an aid in the diagnosis of intrathoracic disease in the dog. Two dogs, one with a history of prior esophageal foreign body extraction, the other with apathy, weakness and dyspnea were referred for further investigation. Both dogs had caudal intrathoracic soft tissue opacities diagnosed radiographically, but their origin and nature were difficult to determine. Conventional ultrasound was limiting in both dogs due to their location and superimposition of gas-filled structures. With endosonography lesions were characterized more completely. We have found endoscopic ultrasound to be an elegant diagnostic tool for the investigation of radiographically detected intrathoracic lesions in the dog whose origins are difficult to determine or do not lend themselves to investigation by conventional ultrasound. Endoscopic ultrasound provides valuable diagnostic information complementary to that provided radiographically which aids in therapeutic planning. Endoscopic ultrasound was also more sensitive for detecting mediastinal lymphadenomegaly than radiography in one of the dogs. An additional advantage of endoscopic ultrasound is the fact that US-guided tissue sampling can be performed during the examination.

Hormonal and Clinical Predictors for Post-egg Retrieval Pain in Women Undergoing Assisted Reproductive Technology Procedures

OBJECTIVES The intensity of post-egg retrieval pain is underestimated, with few studies examining post-procedural pain and predictors to identify women at risk for severe pain. We evaluated the influence of pre-procedural hormonal levels, ovarian factors, as well as mechanical temporal summation (mTS) as predictors for post-egg retrieval pain in women undergoing in vitro fertilization (IVF). METHODS Eighteen women scheduled for ultrasound-guided egg retrieval under standardized anesthesia and post-procedural analgesia were enrolled. Pre-procedural mTS, questionnaires, clinical data related to anesthesia and the procedure itself, post-procedural pain scores and pain medication for breakthrough pain were recorded. Statistical analysis included Pearson product moment correlations, Mann-Whitney U tests and multiple linear regressions. RESULTS Average peak post-egg retrieval pain during the first 24 hours was 5.0±1.6 on an NRS scale (0=no pain, 10=worst pain imaginable). Peak post-egg retrieval pain was correlated with basal antimullerian hormone (AMH) (r=0.549, P=0.018), pre-procedural peak estradiol (r=0.582, P=0.011), total number of follicles (r=0.517, P=0.028) and number of retrieved eggs (r=0.510, P=0.031). Ovarian hyperstimulation syndrome (OHSS) (n=4) was associated with higher basal AMH (P=0.004), higher peak pain scores (P=0.049), but not with peak estradiol (P=0.13). The mTS did not correlate with peak post-procedural pain (r=0.266, P=0.286), or peak estradiol level (r=0.090, P=0.899). DISCUSSION Peak post-egg retrieval pain intensity was higher than anticipated. Our results suggest that post-egg retrieval pain can be predicted by baseline AMH, high peak estradiol, and OHSS. Further studies to evaluate intra- and post-procedural pain in this population are needed, as well as clinical trials to assess post-procedural analgesia in women presenting with high hormonal levels.

Transition from nerve stimulator to sonographically guided axillary brachial plexus anesthesia in hand surgery: block quality and patient satisfaction during the transition period

OBJECTIVES Sonographic guidance for peripheral nerve anesthesia has proven increasingly successful in clinical practice; however, fears that a change to sonographically guided regional anesthesia may impair the block quality and operating room work flow persist in certain units. In this retrospective cohort study, block quality and patient satisfaction during the transition period from nerve stimulator to sonographic guidance for axillary brachial plexus anesthesia in a tertiary referral center were investigated. METHODS Anesthesia records of all patients who had elective surgery of the wrist or hand during the transition time (September 1, 2006-August 25, 2007) were reviewed for block success, placement time, anesthesiologist training level, local anesthetic volume, and requirement of additional analgesics. Postoperative records were reviewed, and patient satisfaction was assessed by telephone interviews in matched subgroups. RESULTS Of 415 blocks, 341 were sonographically guided, and 74 were nerve stimulator guided. Sonographically guided blocks were mostly performed by novices, whereas nerve stimulator-guided blocks were performed by advanced users (72.3% versus 14%; P < .001). Block performance times and success rates were similar in both groups. In sonographically guided blocks, significantly less local anesthetics were applied compared to nerve stimulator-guided blocks (mean ± SD, 36.1 ± 7.1 versus 43.9 ± 6.1 mL; P< .001), and less opioids were required (fentanyl, 66.1 ± 30 versus 90 ± 62 μg; P< .001). Interviewed patients reported significantly less procedure-related discomfort, pain, and prolonged procedure time when block placement was sonographically guided (2% versus 20%; P = .002). CONCLUSIONS Transition from nerve stimulator to sonographic guidance for axillary brachial plexus blocks did not change block performance times or success rates. Patient satisfaction was improved even during the early institutional transition period.

Perforation of the median nerve with an acupuncture needle guided by ultrasound

In an experiment on one of the authors, we used ultrasound to visualise an acupuncture needle completely perforating the median nerve at the acupuncture point PC6. During this procedure only a slight sensation occurred, and no pain. We conclude that, in individual cases, the median nerve might be perforated without causing pain or neurological problems.

Ultrasonographic guided axillary plexus blocks with low volumes of local anaesthetics: a crossover volunteer study

Our study group recently evaluated an ED(95) local anaesthetic volume of 0.11 ml.mm(-2) cross-sectional nerve area for the ulnar nerve. This prospective, randomised, double-blind crossover study investigated whether this volume is sufficient for brachial plexus blocks at the axillary level. Ten volunteers received an ultrasonographic guided axillary brachial plexus block either with 0.11 ('low' volume) or 0.4 ('high' volume) ml.mm(-2) cross-sectional nerve area with mepivacaine 1%. The mean (SD) volume was in the low volume group 4.0 (1.0) and 14.8 (3.8) ml in the high volume group. The success rate for the individual nerve blocks was 27 out of 30 in the low volume group (90%) and 30 out of 30 in the high volume group (100%), resulting in 8 out of 10 (80%) vs 10 out of 10 (100%) complete blocks in the low vs the high volume groups, respectively (NS). The mean (SD) sensory onset time was 25.0 (14.8) min in the low volume group and 15.8 (6.8) min in the high volume group (p < 0.01). The mean (SD) duration of sensory block was 125 (38) min in the low volume group and 152 (70) min in the high volume group (NS). This study confirms our previous published ED(95) volume for mepivacaine 1% to block peripheral nerves. The volume of local anaesthetic has some influence on the sensory onset time.

Ultrasound imaging to estimate risk of esophageal and vascular puncture after conventional stellate ganglion block

The most common techniques to perform stellate ganglion blocks (SGBs) are the blind C6 approach and the fluoroscopic-controlled paratracheal C7 approach, both after manual dislocation of the large vessels. Complications due to vascular or esophageal puncture have been reported. The goal of this ultrasound imaging study was to determine how frequently hazardous structures are located along the needle path of conventional SGB and to determine the influence of the dislocation maneuver on their position.

Vasectomy reversal with ultrasonography-guided spermatic cord block

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Vasectomy reversal is often performed in general or neuraxial anaesthesia. Even though the site of vasectomy reversal is easily amenable to regional/local anaesthesia, spermatic cord blocks are rarely applied because of their risk of vascular damage within the spermatic cord. Recently, we described the technique of ultrasonography (US)-guided spermatic cord block for scrotal surgery, which, thanks to the US guidance, at the same time avoids the risk of vascular damage of blindly performed injections and the risks of general and neuraxial anaesthesia. Vasectomy reversal can easily be done in regional anaesthesia with the newly described technique of US-guided spermatic cord block without the risks of vascular damage by a blindly performed injection and the risks of standard general and neuraxial anaesthesia. In addition, this technique grants long-lasting postoperative pain relief and patients recover more quickly. Microsurgical conditions are excellent and patient satisfaction is high. Thanks to these advantages, more patients undergoing vasectomy reversal might avoid general or neuraxial anaesthesia.

Real-time evaluation of diffusion of the local anesthetic solution during peribulbar block using ultrasound imaging and clinical correlates of diffusion

The aims of this prospective observational study were to assess the incidence of intraconal spread during peribulbar (extraconal) anesthesia by real-time ultrasound imaging of the retro-orbital compartment and to determine whether a complete sensory and motor block (with akinesia) of the eye is directly related to the intraconal spread.

Horizontal ridge augmentation using autogenous block grafts and the guided bone regeneration technique with collagen membranes: a clinical study with 42 patients

OBJECTIVE: To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with an organic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. MATERIAL AND METHODS: In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. RESULTS: Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2-7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. CONCLUSIONS: The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure.

Ultrasound measurements of the distance between acupuncture needle tip at P6 and the median nerve

BACKGROUND: Pericard 6 (P6) is one of the most frequently used acupuncture points, especially in preventing nausea and vomiting. At this point, the median nerve is located very superficially. OBJECTIVES: To investigate the distance between the needle tip and the median nerve during acupuncture at P6, we conducted a prospective observational ultrasound (US) imaging study. We tested the hypothesis that de qi (a sensation that is typical of acupuncture needling) is evoked when the needle comes into contact with the epineural tissue and thereby prevents nerve penetration. SETTINGS/LOCATION: The outpatient pain clinic of the Medical University of Vienna, Austria. SUBJECTS: Fifty (50) patients receiving acupuncture treatment including P6 bilaterally. INTERVENTIONS: Patients were examined at both forearms using US (a 10-MHz linear transducer) after insertion of the needle at P6. OUTCOME MEASURES: The distance between the needle tip and the median nerve, the number of nerve contacts and nerve penetrations, as well as the number of successfully elicited de qi sensations were recorded. RESULTS: Complete data could be obtained from 97 cases. The mean distance from the needle tip to the nerve was 1.8 mm (standard deviation 2.2; range 0-11.3). Nerve contacts were recorded in 52 cases, in 14 of which the nerve was penetrated by the needle. De qi was elicited in 85 cases. We found no association between the number of nerve contacts and de qi. The 1-week follow-up showed no complications or neurologic problems. CONCLUSIONS: This is the first investigation demonstrating the relationship between acupuncture needle placement and adjacent neural structures using US technology. The rate of median nerve penetrations by the acupuncture needle at P6 was surprisingly high, but these seemed to carry no risk of neurologic sequelae. De qi at P6 does not depend on median nerve contact, nor does it prevent median nerve penetration.