Eric vanSonnenberg

Interventions for Necrotizing Pancreatitis Summary of a Multidisciplinary Consensus Conference

Abstract Pancreatic and peripancreatic necrosis may result in significant morbidity and mortality in patients with acute pancreatitis. Many recommendations have been made for management of necrotizing pancreatitis, but no published guidelines have incorporated the many recent developments in minimally invasive techniques for necrosectomy. Hence, a multidisciplinary conference was convened to develop a consensus on interventions for necrotizing pancreatitis. Participants included most international experts from multiple disciplines. The evidence for efficacy of interventions was reviewed, presentations were given by experts, and a consensus was reached on each topic. In summary, intervention is primarily indicated for infected necrosis, less often for symptomatic sterile necrosis, and should ideally be delayed as long as possible, preferably 4 weeks or longer after the onset of disease, for better demarcation and liquefaction of the necrosis. Both the step-up approach using percutaneous drainage followed by minimally invasive video-assisted retroperitoneal debridement and per-oral endoscopic necrosectomy have been shown to have superior outcomes to traditional open necrosectomy with respect to short-term and long-term morbidity and are emerging as treatments of choice. Applicability of these techniques depends on the availability of specialized expertise and a multidisciplinary team dedicated to the management of severe acute pancreatitis and its complications.

Percutaneous Abscess Drainage: Update

During the approximately 20 years that percutaneous abscess drainage (PAD) has been an extant procedure and as the millennium begins, PAD has become, by consensus, the treatment of choice for abscesses. Indications for PAD continue to expand, and currently almost all abscesses are considered amenable. On occasion, PAD is an adjunctive procedure that provides a beneficial temporizing effect for the surgeon who eventually must operate for a coexisting problem such as a bowel leak. Simple unilocular abscesses are cured almost uniformly by PAD; more complicated abscesses, such as those with enteric fistulas (e.g., diverticular abscess) or pancreatic abscesses, have cure rates ranging from 65% to 90%. Various catheters and insertion techniques have proven effective. Ultrasonography, computed tomography, and fluoroscopy are the staple modalities that guide PAD. PAD is the prototype interventional radiology procedure, providing detection of the abscess by imaging, needling for diagnosis, and catheterization for therapy.

Magnetic resonance imaging of the upper airway. Effects of propofol anesthesia and nasal continuous positive airway pressure in humans.

Background Anesthetic agents inhibit the respiratory activity of upper airway muscles more than the diaphragm, creating a potential for narrowing or complete closure of the pharyngeal airway during anesthesia. Because the underlying mechanisms leading to airway obstruction in sleep apnea and during anesthesia are similar, it was hypothesized that anesthesia-induced pharyngeal narrowing could be counteracted by applying nasal continuous positive airway pressure (CPAP). Methods Anesthesia was induced in ten healthy volunteers (aged 25-34 yr) by intravenous administration of propofol in 50-mg increments every 30-s to a maximum of 300 mg. Magnetic resonance images of the upper airway (slice thickness of 5 mm or less) were obtained in the awake state, during propofol anesthesia, and during administration of propofol plus 10 cm nasal CPAP. Results Minimum anteroposterior diameter of the pharynx at the level of the soft palate decreased from 6.6+/-2.2 mm (SD) in the awake state to 2.7+/-1.5 mm (P < 0.05) during propofol anesthesia and increased to 8.43+/-2.5 mm (P < 0.05) after nasal CPAP application. Anteroposterior diameter of the pharynx at the level of the dorsum of the tongue increased from 7.9+/-3.5 mm during propofol anesthesia to 12.9+/-3.6 mm (P < 0.05) after nasal CPAP. Pharyngeal volume (from the tip of the epiglottis to the tip of the soft palate, assuming this space to be a truncated cone) significantly increased from 2,437+/-1,008 mm3 during propofol anesthesia to 5,847+/-2,827 mm3 (P < 0.05) after nasal CPAP application. Conclusions In contrast to the traditional view that relaxation of the tongue causes airway obstruction, this study suggests that airway closure occurs at the level of the soft palate. Application of nasal CPAP can counteract an anesthesia-induced pharyngeal narrowing by functioning as a pneumatic splint. This is supported by the observed reduction in anteroposterior diameter at the level of the soft palate during propofol anesthesia and the subsequent increase in this measurement during nasal CPAP application.

Preoperative percutaneous drainage of diverticular abscesses

To define the role of percutaneous catheter drainage in the initial management of diverticular abscess, we reviewed 19 patients who were followed for an average of 17.4 months after drainage. All patients had large paracolic or pelvic abscesses with a mean size of 8.9 cm. There were no complications related to catheter placement, and 15 patients (79 percent) required drainage for less than 3 weeks. Sepsis resolved rapidly, and only two patients (11 percent) had persistent fever or leukocytosis beyond the third day of drainage. Routine sinography revealed fistulous communications to the colon in nine patients (47 percent), but only three (16 percent) had grossly feculent drainage. Fourteen patients (74 percent) completed the treatment plan of preoperative catheter drainage followed by single-stage sigmoid colectomy and primary anastomosis without complications. Two patients refused operation, one of whom died 16 days postoperatively from recurrent sepsis and end-stage pulmonary disease. The three patients with fecal fistulas all had inadequate control of infection, suggesting the need for early operation and fecal diversion in such cases. We conclude that preoperative percutaneous catheter drainage obviates the need for colostomy and multiple-stage surgery in approximately three-fourths of patients with large diverticular abscesses.

Pulmonary Embolism at CT Angiography: Implications for Appropriateness, Cost, and Radiation Exposure in 2003 Patients

PURPOSE To determine whether thromboembolic risk factor assessment could accurately indicate the pretest probability for pulmonary embolism (PE), and if so, computed tomographic (CT) angiography might be targeted more appropriately than in current usage, resulting in decreased costs and radiation exposure. MATERIALS AND METHODS Institutional review board approval was obtained. Electronic medical records of 2003 patients who underwent CT angiography for possible PE during 1(1/2) years (July 2004 to February 2006) were reviewed retrospectively for thromboembolic risk factors. Risk factors that were assessed included immobilization, malignancy, hypercoagulable state, excess estrogen state, a history of venous thromboembolism, age, and sex. Logistic regressions were conducted to test the significance of each risk factor. RESULTS Overall, CT angiograms were negative for PE in 1806 (90.16%) of 2003 patients. CT angiograms were positive for PE in 197 (9.84%) of 2003 patients; 6.36% were Emergency Department patients, and 13.46% were inpatients. Of the 197 patients with CT angiograms positive for PE, 192 (97.46%) had one or more risk factors, of which age of 65 years or older (69.04%) was the most common. Of the 1806 patients with CT angiograms negative for PE, 520 (28.79%) had no risk factors. The sensitivity and negative predictive value of risk factor assessment in all patients were 97.46% and 99.05%, respectively. All risk factors, except sex, were significant in the multivariate logistic regression (P < .031). CONCLUSION In the setting of no risk factors, it is extraordinarily unlikely (0.95% chance) to have a CT angiogram positive for PE. This selectivity and triage step should help reduce current costs and radiation exposure to patients.

MRI-guided percutaneous cryotherapy for soft-tissue and bone metastases: initial experience.

OBJECTIVE We sought to determine the safety and feasibility of percutaneous MRI-guided cryotherapy in the care of patients with refractory or painful metastatic lesions of soft tissue and bone adjacent to critical structures. MATERIALS AND METHODS Twenty-seven biopsy-proven metastatic lesions of soft tissue (n = 17) and bone (n = 10) in 22 patients (15 men, seven women; age range, 24-85 years) were managed with MRI-guided percutaneous cryotherapy. The mean lesion diameter was 5.2 cm. Each lesion was adjacent to or encasing one or more critical structures, including bowel, bladder, and major blood vessels. A 0.5-T open interventional MRI system was used for cryoprobe placement and ice-ball monitoring. Complications were assessed for all treatments. CT or MRI was used to determine local control of 21 tumors. Pain palliation was assessed clinically in 19 cases. The mean follow-up period was 19.5 weeks. RESULTS Twenty-two (81%) of 27 tumors were managed without injury to adjacent critical structures. Two patients had transient lower extremity numbness, and two had both urinary retention and transient lower extremity paresthesia. One patient had chronic serous vaginal discharge, and one sustained a femoral neck fracture at the ablation site 6 weeks after treatment. Thirteen (62%) of the 21 tumors for which follow-up information was available either remained the same size as before treatment or regressed. Eight tumors progressed (mean local progression-free interval, 5.6 months; range, 3-18 months). Pain was palliated in 17 of 19 patients; six of the 17 experienced complete relief, and 11 had partial relief. CONCLUSION MRI-guided percutaneous cryotherapy for metastatic lesions of soft tissue and bone adjacent to critical structures is safe and can provide local tumor control and pain relief in most patients.

Bile Duct Obstruction in Hepatocellular Carcinoma (Hepatoma)—Clinical and Cholangiographic Characteristics: Report of 6 Cases and Review of the Literature

Direct cholangiography revealed 6 cases of hepatoma where tumor growth within the bile ducts caused obstructive jaundice. Characteristic features included bulky obstructing intraluminal masses in the proximal extrahepatic ducts. Distal common duct defects usually signify hemobilia and clots as tumor complication. Review of the literature disclosed only 22 cases in which common duct involvement was a predominant clinical feature. Hepatoma should be included in the different diagnosis of a cholangiographic filling defect in the proximal extrahepatic bile ducts. The recent widespread use of endoscopic and fine needle transhepatic cholangiography should aid in preoperative diagnosis.

Basilar pneumothorax in the supine adult.

A pneumothorax in a supine patient may outline the anterior costophrenic sulcus, resulting in an abrupt curvilinear change in density projected over the right or left upper quadrant, which is normally convex inferiorly. The upper quadrant will also appear relatively lucent. In a small pneumothorax these may be the only radiographic findings when the patient is supine. This can be easily identified on mobile-unit radiographs of limited technical quality. Either finding should lead to a prompt cross-table lateral or decubitus study to confirm the diagnosis and allow estimation of the size of the pneumothorax.

Imaging and Percutaneous Management of Acute Complicated Pancreatitis

Acute pancreatitis varies from a mild, self-limited disease to one with significant morbidity and mortality in its most severe forms. While clinical criteria abound, imaging has become indispensable to diagnose the extent of the disease and its complications, as well as to guide and monitor therapy. Percutaneous interventional techniques offer options that can be life-saving, surgery-sparing or important adjuncts to operation. Close cooperation and communication between the surgeon, gastroenterologist and interventional radiologist enhance the likelihood of successful patient care.

Percutaneous drainage of infected and noninfected thoracic fluid collections

Radiologically guided aspiration and drainage of thoracic fluid collections is an improvement on standard “blind” techniques for chest-tube insertion. Specific indications for radiologic drainage are broadening, and instead of failed surgical cases only, patients now are commonly referred for drainage. Most of these procedures are effective and the complication rate vis-à-vis alternatives is acceptable. Soft 12-F catheters suffice in most cases and are relatively comfortable compared to large-bore tubes.