[Intrahepatic cholangiocarcinoma : Results after 84 resections]

BACKGROUND

The incidence of intrahepatic cholangiocarcinoma (ICC) is increasing worldwide. Surgical resection is the only curative treatment option.

AIM OF THE STUDY

This study analyzed the prognostic factors after resection of ICC.

MATERIAL AND METHODS

A total of 84 patients were surgically treated under potentially curative intent. Perihilar and distal cholangiocarcinomas were excluded. The 5‑year survival was analyzed with respect to tumor stage (TNM), number of lesions, complete surgical resection (R0), peritoneal carcinosis and postoperative complications.

RESULTS

The 5‑year survival was 27% and 77% of patients underwent R0 resections. In the univariate analysis a T stage >2, an N+ situation or an R+ resection as well as peritoneal and multilocular intrahepatic spread were associated with a poorer prognosis. Postoperative complications also negatively influenced survival. On multivariate analysis the absence of peritoneal spread, node-negative tumor stages, singular hepatic lesions and a low T stage as well as the absence of complications were associated with improved survival.

DISCUSSION

The prognosis of ICC is poor even after successful surgical resection. Well-known tumor characteristics such as TNM are relevant prognostic factors. Surgical resection is accompanied by postoperative complications (most frequently biliary), which negatively influence survival. Adjuvant strategies are urgently needed to improve long-term survival even after complete surgical resection.

Cyclosporine A Inhibits the T-bet-Dependent Antitumor Response of CD8(+) T Cells

Transplant recipients face an increased risk of cancer compared with the healthy population. Although several studies have examined the direct effects of immunosuppressive drugs on cancer cells, little is known about the interactions between pharmacological immunosuppression and cancer immunosurveillance. We investigated the different effects of rapamycin (Rapa) versus cyclosporine A (CsA) on tumor-reactive CD8(+) T cells. After adoptive transfer of CD8(+) T cell receptor-transgenic OTI T cells, recipient mice received either skin grafts expressing ovalbumin (OVA) or OVA-expressing B16F10 melanoma cells. Animals were treated daily with Rapa or CsA. Skin graft rejection and tumor growth as well as molecular and cellular analyses of skin- and tumor-infiltrating lymphocytes were performed. Both Rapa and CsA were equally efficient in prolonging skin graft survival when applied at clinically relevant doses. In contrast to Rapa-treated animals, CsA led to accelerated tumor growth in the presence of adoptively transferred tumor-reactive CD8(+) OTI T cells. Further analyses showed that T-bet was downregulated by CsA (but not Rapa) in CD8(+) T cells and that cancer cytotoxicity was profoundly inhibited in the absence of T-bet. CsA reduces T-bet-dependent cancer immunosurveillance by CD8(+) T cells. This may contribute to the increased cancer risk in transplant recipients receiving calcineurin inhibitors.

mTOR inhibition improves fibroblast growth factor receptor targeting in hepatocellular carcinoma

Background:

Systemic therapy has proven only marginal effects in hepatocellular carcinoma (HCC) so far. The aim of this study was to evaluate the effect of targeting fibroblast growth factor receptor (FGFR) on tumour and stromal cells in HCC models.

Methods:

Human and murine HCC cells, endothelial cells (ECs), vascular smooth muscle cells (VSMCs), hepatic stellate cells (HSCs), human HCC samples, FGFR inhibitor BGJ398 and mammalian target of rapamycin (mTOR) inhibitor rapamycin were used. Effects on growth, motility, signalling and angiogenic markers were determined. In vivo subcutaneous and syngeneic orthotopic tumour models were used.

Results:

In tumour cells and ECs, targeting FGFR showed significant inhibitory effects on signalling and motility. Minor effects of FGFR inhibition were observed on VSMCs and HSCs, which were significantly enhanced by combining FGFR and mTOR blockade. In vivo daily (5 mg kg⁻¹) treatment with BGJ398 led to a significant growth inhibition in subcutaneous tumour models, but only a combination of FGFR and mTOR blockade impaired tumour growth in the orthotopic model. This was paralleled by reduced tumour cell proliferation, vascularisation, pericytes and increased apoptosis.

Conclusions:

Targeting FGFR with BGJ398 affects tumour cells and ECs, whereas only a combination with mTOR inhibition impairs recruitment of VSMCs and HSCs. Therefore, this study provides evidence for combined FGFR/mTOR inhibition in HCC.

["In-situ split" (ISS) liver resection: new aspects of technique and indication]

The combination of right portal vein ligation with complete parenchyma dissection ("in-situ split", ISS) for rapid hypertrophy induction of the left-lateral liver lobe is a novel strategy to convert primarily irresectable liver tumours into a resectable stage. Available data so far show a 60-80 % growth induction of the remnant liver within 7(- 9) days. Certainly, a novel concept that comprises two operations within a very short time period raises questions. Based on the very few literature reports that have been published so far, as well as our own experience, we here discuss technical issues such as the use of a plastic sheet on the resection margin, the possibility of laparoscopic dissection and the timing of the second operation. Moreover, aspects of the preoperative diagnostic work-up that is necessary are assessed. Finally, open questions, e.g., concerning the influence of preoperative chemotherapy and the use of ISS in patients with cirrhosis are evaluated. In summary, the assessment of chances and risks of this novel concept with regard to indication and technical issues helps to provide the potentially curative option of the "in-situ split" procedure to more patients with marginal or even irresectable liver tumours.

[Biliodigestive anastomosis: indications, complications and interdisciplinary management]

Techniques for biliodigestive anastomoses are a frequent indication in primary surgical interventions. Moreover, they are required to manage secondary complications of hepatobiliary surgery. Evidence for the management of complications following biliodigestive anastomoses is low. Biliodigestive anastomoses can be performed as hepaticojejunostomy, hepatojejunostomy/portoenterostomy and hepaticoduodenostomy using running or single stitch suture techniques. Complication management in the hands of experienced hepatopancreatobiliary surgeons should consider a time delay to the primary operation and an interdisciplinary surgical and/or endoscopic or radiologic interventional approach. The therapy may be protracted and requires repeated critical reflection of the particular complication.

Effects of ASA404, a vascular disrupting agent, on tumor growth of gastric cancer in an experimental model

48

Background: A functional vascular system is essential for growth of solid malignancies including gastric cancer. For establishment and maintenance of such a vascular system endothelial cells (ECs) and pericytes (e.g. vascular smooth muscle cells, VSMC) are required. We hypothesized that targeting tumor vasculature with the vascular disrupting agent (VDA) ASA404 (Novartis Oncology) reduces tumor growth in a model of gastric cancer.

Methods: Gastric cancer (GC) cell lines, ECs and VSMCs were used for experiments. Effects of ASA404 on growth of GC, EC and VSMC were assessed by MTT assays. Impact of ASA404 (20 mg/kg on day 1, 5, 9) in combination with paclitaxel (10 mg/kg on day 1 and 7) on tumor growth was assessed in a subcutaneous tumor model. Treatment was started when tumors reached a size of approximately 200 mm3. Tumors were measured and harvested on day 23 for IHC analyses. Effect of ASA404 on blood perfusion of tumors during therapy was monitored by contrast-enhanced ultrasound (CEUS).

Results: In vitro ASA404 impaired growth of ECs and VSMCs upon stimulation with condition media from gastric cancer cells. No direct effect on tumor cells was observed. In vivo, treatment with ASA404 led to marked decrease of tumor perfusion and an increase of necrosis as determined by CEUS. Furthermore, combination of ASA404 with paclitaxel showed significant reduction of tumor growth compared to controls (p < 0.05). In addition, tumor vascularisation and tumor cell proliferation were significantly reduced as determined by CD31-positive vessel area and BrdU-positive cells (p < 0.05).

Conclusions: Combination of the VDA ASA404 with paclitaxel impairs tumor growth and perfusion of gastric cancer in an experimental model. Hence, targeting tumor vasculature with ASA404 appears to be a promising strategy for therapy of gastric cancer.

No significant financial relationships to disclose.

Signal transducer and activator of transcription 5b (STAT5b) as a novel target for anti-neoplastic therapy in human pancreatic cancer

217

Background: Activation of signal transducer and activator of transcription 5b (STAT5b) has been associated with tumor growth and metastases in various tumor entities. A number of cytokines, growth factors, and oncogenes that can induce STAT5b activity are also implicated in pancreatic cancer growth and metastases. Hence, we sought to determine STAT5b expression in human pancreatic cancer specimen and effects of selective STAT5b inhibition on pancreatic cancer cells.

Methods: Expression of STAT5b in human pancreatic adenocarcinomas was determined by immunohistochemistry. For in vitro experiments, human pancreatic cancer cell lines (BxPC-3, HPAF-II, L3.6pl) were used. Cancer cells were transfected with STAT5b shRNA plasmid to create stable STAT5b knock-down. Effects of STAT5b inhibition on growth and motility of tumor cells was investigated by MTT and modified Boyden chamber assays. In vivo effects of STAT5b blockade were determined in subcutaneous mouse model.

Results: Nuclear expression of STAT5b was detected in 42/80 human pancreatic adenocarcinomas. In human cancer cell lines, stable knock-down of STAT5b had no effect on growth of tumor cells in vitro. However, tumor cell motility was significantly reduced upon STAT5b blockade (p<0.05). Moreover, expression of various signaling intermediates and transcription factors including c-myc was impaired upon STAT5b knock-down. In a subcutaneous tumor model, inhibition of STAT5b led to significantly reduced tumor growth (p<0.05) which was also reflected by final tumor weights (p<0.05). Furthermore, as revealed by immunohistochemistry, blockade of STAT5b significantly reduced tumor vascularization in vivo (p<0.05).

Conclusions: STAT5b is expressed in human pancreatic adenocarcinomas. Blockade of STAT5b impairs cancer cell motility in vitro, suggesting antimetastatic potential. Moreover, inhibition of STAT5b significantly reduces tumor growth and tumor vascularization in vivo. Hence, STAT5b might be an interesting target for antineoplastic therapy in human pancreatic cancer.

No significant financial relationships to disclose.

TdTomato and EGFP identification in histological sections: insight and alternatives

Tandem dimer Tomato (tdTomato) provides a useful alternative to enhanced green fluorescent protein (eGFP) for performing simultaneous detection of fluorescent protein in histological sections together with fluorescence immunohistochemistry (IHC). eGFP has many properties that make it useful for cell labeling; however, during simultaneous fluorescence IHC, the usefulness of eGFP may be limited. This limitation results from a fixation step required to identify eGFP in histological tissue sections that can mask antibody epitopes and adversely affect staining intensity. An alternative fluorescent protein, tdTomato, may assist concurrent detection of fluorescent protein within tissue sections and fluorescence IHC, because detection of tdTomato does not require tissue fixation. Tissue sections were obtained from various organs of mice ubiquitously expressing eGFP or tdTomato that were either unfixed or fixed with 4% paraformaldehyde. These tissues later were combined with fluorescence IHC. Both eGFP and tdTomato displayed robust signals in fixed frozen sections. Only tdTomato fluorescence, however, was detected in unfixed frozen sections. Simultaneous detection of fluorescence IHC and fluorescent protein in histological sections was observed only in unfixed frozen tdTomato tissue. For this reason, tdTomato is a useful substitute for eGFP for cell labeling when simultaneous fluorescence IHC is required.

[The techniques of peritonectomy and hyperthermic intraperitoneal chemotherapy]

The treatment of peritoneal carcinomatosis represents a challenge in the therapy for gastrointestinal cancer. A multimodal approach with complete surgical cytoreduction and hyperthermic intraperitoneal chemotherapy can improve the prognosis in selected patients. Complete surgical cytoreduction, consisting of parietal and visceral peritonectomy, is a sophisticated procedure, frequently requiring multivisceral resections and should only be performed by experienced visceral surgeons. In addition, hyperthermic intraperitoneal chemotherapy is of some complexity. Furthermore, regarding the learning curve for this procedure, combined treatment should only be performed in specialised centres. Under optimal conditions, the therapy can be carried out with reasonable morbidity and mortality rates. Patients with peritoneal carcinomatosis should be evaluated by an interdisciplinary team concerning this multimodal therapy option and, if applicable, they should be referred to therapy within the framework of clinical studies.

Mesenchymal stem cells can induce long-term acceptance of solid organ allografts in synergy with low-dose mycophenolate

The induction of tolerance towards allogeneic solid organ grafts is one of the major goals in transplantation medicine. Mesenchymal stem cells (MSC) inhibit the immune response in vitro, and thus are promising candidate cells to promote acceptance of transplanted organs in vivo. Such novel approaches of tolerance induction are needed since, to date, graft acceptance can only be maintained through life-long treatment with unspecific immunosuppressants that are associated with toxic injury, opportunistic infections and malignancies. We demonstrate that donor-derived MSC induce long-term allograft acceptance in a rat heart transplantation model, when concurrently applied with a short course of low-dose mycophenolate. This tolerogenic effect of MSC is at least partially mediated by the expression of indoleamine 2,3-dioxygenase (IDO), demonstrated by the fact that blocking of IDO with 1-methyl tryptophan (1-MT) abrogates graft acceptance. Moreover we hypothesize that MSC interact with dendritic cells (DC) in vivo, because allogeneic MSC are rejected in the long-term but DC acquire a tolerogenic phenotype after applying MSC. In summary, we demonstrate that MSC constitute a promising tool for induction of non-responsiveness in solid organ transplantation that warrants further investigation in clinical trials.

Mesenteric ischemia--outcome after surgical therapy in 83 patients

BACKGROUND

Intestinal ischemia is the prime vascular emergency for the visceral surgeon. However, the diagnosis of mesenteric ischemia is difficult, the surgical options are often limited and the overall outcome is generally poor.

METHODS

We report on a single center series of 83 patients undergoing surgery for mesenteric ischemia during a 3-year period. Risk factors, clinical presentation, type and timing of imaging studies and their implications for surgical therapy and outcome are analyzed.

RESULTS

Hypertension and diabetes were the most common risk factors (68/64% of all patients). Abdominal pain was the most general symptom upon presentation to the surgical unit (73%). Two-phase, contrast-enhanced computed tomography was applied as the standard preoperative imaging modality (correct diagnosis in 69%). Bowel resections were necessary in most patients; approaches to restore blood flow by vascular surgery interventions were applied in 17 patients (20%). The overall morbidity and mortality rate in our study cohort was expectedly high (59% 1 month mortality).

CONCLUSION

The diagnosis and surgical treatment of mesenteric ischemia remains a major difficulty. We recommend preoperative CT analysis followed by an aggressive indication for early surgical exploration and bowel resection. An attempt of revascularization is justified for selected patients with limited macrovascular disease.

[Peritoneal carcinomatosis. Surgical treatment, including hyperthermal intraperitoneal chemotherapy]

Colorectal cancer is a common malignant disease with increasing incidence and a significant cause of death in cancer patients. More than 10% of patients with colorectal cancer show peritoneal carcinomatosis at initial diagnosis. Moreover, peritoneal metastasis is a common sign of recurrence. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are a new treatment strategy for highly selected patients with peritoneal carcinomatosis. Numerous studies show prolonged survival after CRS and HIPEC with acceptable morbidity and mortality rates. Accurate preoperative diagnostics and patient selection play a pivotal role in postoperative patient outcome. This promising treatment strategy is discussed regarding surgical technique, intraperitoneal chemotherapy, and patient outcome.

Multimodality treatment of peritoneal carcinomatosis from colorectal cancer: first results of a new German centre for peritoneal surface malignancies

BACKGROUND

The presence of peritoneal carcinomatosis arising from colorectal cancer is associated with a poor prognosis. It was the purpose of this study to analyze morbidity, mortality, and survival after major cytoreductive surgery and intraperitoneal chemotherapy.

MATERIALS AND METHODS

Thirty-two patients with peritoneal carcinomatosis were operated between April 2004 and June 2006 with the aim of complete macroscopical cytoreduction. All had a primary colorectal carcinoma. Surgery in these patients was followed by hyperthermic intraperitoneal chemotherapy (HIPEC) consisting of mitomycin C and doxorubicin. Data were analyzed retrospectively.

RESULTS

Of all patients, 16 had appendix and 16 non-appendiceal colorectal carcinoma. A macroscopically complete cytoreduction was achieved in 24 patients by parietal and visceral peritonectomy procedures. All resections were combined with HIPEC. Overall morbidity was 34%. Most frequent surgical complications were intestinal obstruction (4/32), enteric fistula (2/32), pancreatitis (2/32), and bile leakage (2/32). One patient presented grade 4 renal toxicity. There was no hospital mortality. The median follow-up was 12 months. The 1-year overall survival rate is 96%. All patients after complete cytoreduction are still alive.

CONCLUSIONS

Cytoreductive surgery combined with HIPEC is associated with an acceptable morbidity and low mortality. Complete cytoreduction may improve survival, particularly in well-selected patients having a low tumor volume and no extra-abdominal metastases.

Who is willing to take the risk? Assessing the readiness for living liver donation in the general German population

BACKGROUND

Shortage of donor organs is one of the major problems for liver transplant programmes. Living liver donation is a possible alternative, which could increase the amount of donor organs available in the short term.

OBJECTIVE

To assess the attitude towards living organ donation in the general population to have an overview of the overall attitude within Germany.

METHODS

A representative quota of people was evaluated by a mail questionnaire (n = 250). This questionnaire had 24 questions assessing the willingness to be a living liver donor for different potential recipients. Factors for and against living liver donation were assessed.

RESULTS

Donating a part of the liver was almost as accepted as donating a kidney. The readiness to donate was highest when participants were asked to donate for children. In an urgent life-threatening situation the will to donate was especially high, whereas it was lower in the case of recipient substance misuse. More women than men expressed a higher disposition to donate for their children. Sex, religion, state of health and age of the donor, however, did not influence other questions on the readiness to consider living organ donation. The will for postmortem organ donation positively correlated with the will to be a living organ donor.

CONCLUSIONS

The motivation in different demographic subgroups to participate in living liver transplantation is described. Differences in donation readiness resulting from the situation of every donor and recipient are thoroughly outlined. The acceptance for a living liver donation was found to be high - and comparable to that of living kidney donation.

Inhibition of influenza A virus replication by compounds interfering with the fusogenic function of the viral hemagglutinin

Several compounds that specifically inhibited replication of the H1 and H2 subtypes of influenza virus type A were identified by screening a chemical library for antiviral activity. In single-cycle infections, the compounds inhibited virus-specific protein synthesis when added before or immediately after infection but were ineffective when added 30 min later, suggesting that an uncoating step was blocked. Sequencing of hemagglutinin (HA) genes of several independent mutant viruses resistant to the compounds revealed single amino acid changes that clustered in the stem region of the HA trimer in and near the HA2 fusion peptide. One of the compounds, an N-substituted piperidine, could be docked in a pocket in this region by computer-assisted molecular modeling. This compound blocked the fusogenic activity of HA, as evidenced by its inhibition of low-pH-induced cell-cell fusion in infected cell monolayers. An analog which was more effective than the parent compound in inhibiting virus replication was synthesized. It was also more effective in blocking other manifestations of the low-pH-induced conformational change in HA, including virus inactivation, virus-induced hemolysis of erythrocytes, and susceptibility of the HA to proteolytic degradation. Both compounds inhibited viral protein synthesis and replication more effectively in cells infected with a virus mutated in its M2 protein than with wild-type virus. The possible functional relationship between M2 and HA suggested by these results is discussed.

Effect of neuropeptide Y on hemodynamics of the rabbit lung

We evaluated the effect of neuropeptide Y (NPY) on the hemodynamics of the isolated rabbit lung perfused at constant flow and outflow pressure. Doses of 10(-8) and 10(-7) M NPY increased pulmonary arterial pressure (Ppa) from 11.5 +/- 1.0 (SE) mmHg to, respectively, 16.4 +/- 1.5 and 26.0 +/- 3.8 mmHg (P < 0.05, n = 5 mmHg lungs), with 78 +/- 4% of the increase at 10(-7) M resulting from an increased arterial resistance. At the latter dose, pulmonary capillary pressure increased from 5.8 +/- 0.9 to 9.4 +/- 1.0 mmHg (P < 0.05). When administered in the presence of norepinephrine, 10(-8) and 10(-7) M NPY (n = 6) produced extreme increases in Ppa to 66.1 +/- 20.5 and 114.7 +/- 25.5 mmHg, respectively, that were due primarily to an increased arterial resistance. To determine the significance of circulating NPY as a pulmonary vasoactive agent, we measured plasma NPY-like immunoreactivity in anesthetized rabbits after massively activating the sympathetic nervous system with veratrine. NPY-like immunoreactivity increased from 74 +/- 10 to 111 +/- 10 (SE) pM (P < 0.05). Thus, although NPY is a potent vasoconstrictor in the rabbit lung, it is not likely that plasma NPY concentrations rise sufficiently, even after massive sympathetic nervous system activation, to produce pulmonary vasoconstriction in the intact rabbit.

Continuous parasacral sciatic nerve block: two case reports

OBJECTIVE

This study investigated the use of a continuous parasacral sciatic nerve block for anesthesia and postoperative analgesia for lower extremity surgery.

METHODS

A continuous parasacral sciatic nerve block was performed in two patients (triple ankle arthrodesis and below-knee amputation). The sacral plexus was identified using an insulated Tuohy needle and a nerve stimulator. A catheter was placed near the elements of the sacral plexus via the Tuohy needle.

RESULTS

In both patients, surgical anesthesia was successfully established through the parasacral catheter with lidocaine 1% (1/200,000 epinephrine), and postoperative analgesia was successfully established with a bolus of bupivacaine 0.375% (1/200,000 epinephrine) and maintained with a continuous infusion of bupivacaine 0.1% (8 mL/h) for 48 hours.

CONCLUSION

We conclude that continuous parasacral sciatic nerve block can provide anesthesia and long-term analgesia for operative procedures of the foot and leg.

The parasacral sciatic nerve block

BACKGROUND AND OBJECTIVES

The clinical utility of a new parasacral approach for conduction block of the sciatic nerve was investigated, with critical examination of onset, extent, and success rates when this block was used for surgical procedures below the knee.

METHODS

Thirty ASA I-III patients presenting for surgery on the lower limb were enrolled. All received 30 mL of 1.5% lidocaine with 1:200,000 epinephrine following nerve stimulator identification of the sciatic nerve at < or =0.2 mA or less. Trans-sartorial saphenous nerve blocks were performed to provide anesthesia to the medial leg.

RESULTS

Overall success for surgical anesthesia with this block was 97%. All components of the sacral plexus could be blocked with this approach, and 93% of patients displayed evidence of obturator nerve motor block. However, no patient displayed evidence of obturator sensory anesthesia that could be mapped. Saphenous nerve blocks were 100% effective in providing surgical anesthesia for the procedures performed.

CONCLUSIONS

The parasacral approach to the sciatic nerve exhibits a high success rate, resulting in anesthesia of the entire sacral plexus and generally in motor block of the obturator nerve was an interesting observation.

Saphenous nerve anaesthesia--a nerve stimulator technique

PURPOSE

This two part study was undertaken to assess both the feasibility of identifying the saphenous nerve with a nerve stimulator and to assess the efficacy of saphenous nerve anaesthesia with electrical isolation of the nerve.

METHODS

(Part I): In Part I we studied 25 volunteers. Each had saphenous nerve blocks performed using a nerve stimulator (NS) and loss of resistance (LOR) technique. We recorded 10 cm linear visual analogue pain scores on completion of the blocks, time to completion of the blocks, onset time, and success of the blocks. (Part II): Clinical utility of the NS technique of saphenous nerve block was investigated. We evaluated the NS technique in 21 consecutive patients having surgery below the knee.

RESULTS

(Part I): The LOR technique successfully produced saphenous nerve anaesthesia in 18/25 (72%) volunteers and the NS technique was successful in all volunteers (25/25-P < 0.05). The nerve stimulator approach required more time to complete (NS 13 +/- 7 min vs LOR 8 +/- 2 min; P < 0.05). Visual analogue pain scores differed (P < 0.05) with a median of 1.0 cm for the LOR technique and a median of 2 cm for the NS technique. (Part II): The saphenous nerve block was successful in 20/21 (95%) of the patients.

CONCLUSIONS

(Part I): The first part of the study established the feasibility of electrical identification of the saphenous nerve and demonstrated that the NS technique could be utilized to provide superior anaesthesia of the saphenous nerve when compared with a previously validated LOR technique. (Part II): The clinical utility of the NS technique of saphenous nerve block was successfully demonstrated.

Femoral nerve block. Single injection versus continuous infusion for total knee arthroplasty

BACKGROUND AND OBJECTIVES

This study was conducted to ascertain whether there is any advantage to the continuous-infusion femoral 3-in-1 nerve block over the single-injection femoral nerve block for postoperative analgesia after total knee arthroplasty.

METHODS

A double-blind, randomized, controlled study was made of 33 patients undergoing total knee arthroplasty, who were randomized into three groups. Group 1 received a single-injection femoral 3-in-1 nerve block with 20 mL 0.5% bupivacaine with 1:200,000 epinephrine. Group 2 had a catheter placed in the femoral nerve sheath, through which a continuous femoral 3-in-1 nerve block was established. Group 3 patients served as controls. All blocks were performed and assessed prior to induction of standardized general anesthesia. All patients received morphine via patient-controlled analgesia. Pain was recorded on a 100-mm visual analog scale at rest and with motion of the knee. Opioid consumption and side effects were recorded; P = .05 was considered statistically significant.

RESULTS

In the recovery room, pain scores with motion were lower in the single-injection and continuous-infusion groups (P < .05). There were no significant differences between any of the groups regarding pain scores or morphine requirements beyond the recovery room. The incidence of nausea was higher in the control group. There were no differences between the groups with respect to overall patient satisfaction.

CONCLUSIONS

We were unable to confirm improvements in analgesia provided by continuous-infusion femoral 3-in-1 nerve block for total knee arthroplasty except in the recovery room.

Lateral femoral cutaneous nerve block revisited. A nerve stimulator technique

BACKGROUND AND OBJECTIVES

Regional block of the lateral femoral cutaneous nerve (LFCN) often has disappointing success rates despite the large volumes of local anesthetic used. This study was undertaken to investigate the utility of using a nerve stimulator (NS) to localize and block the LFCN.

METHODS

After obtaining institutional approval and informed consent, the authors proceeded with a two-stage study. In stage 1, 20 ASA 1 volunteers underwent LFCN block by both a fan and a NS technique in a prospective, randomized, crossover study utilizing strict criteria for success and extent of block. To predict clinical utility, 20 patients underwent LFCN block by the NS technique using the same assessment criteria (stage 2). Statistical analysis for the comparisons was completed employing the Fisher's exact or paired t-test as appropriate. P < .05 was considered significant.

RESULTS

The NS technique significantly improved the success of LFCN block over the fan technique (100% vs. 40%, P = .00002). The extent of successful blocks was no different with the two techniques. Success in stage 2 was similar to that in stage 1 (85%) predicting clinical utility.

CONCLUSIONS

A NS can be used to localize a purely sensory nerve; such as the LFCN, and improve success rates in regional anesthesia.

Superior laryngeal nerve block: an anatomical study

Superior laryngeal nerve anaesthesia is frequently used to facilitate endotracheal intubation in the awake patient. We have modified the transcutaneous approach to this nerve block to employ a short bevel needle. This improves tactile perception in performing the procedure thus simplifying identification of the correct depth of injection. This study was designed to determine the anatomical basis of superior laryngeal nerve anaesthesia and to estimate the success rate using our modified technique. At autopsy, 20 cadavers had nerve block performed substituting 0.02% methylene blue for local anaesthetic. Dissection was then performed to identify the anatomical structures stained by the simulated local anaesthetic. Additional dissections were performed in formalin-fixed cadavers. We found that the dye was injected into the paraglottic space bounded laterally by the thyrohyoid membrane and thyroid cartilage, medially by the laryngeal submucosa, caudad by the conus elasticus, cephalad by the hyoid bone, and anteriorly and posteriorly by the anterior and posterior thyrohyoid ligaments, respectively. The internal laryngeal nerve, the sensory branch of the superior laryngeal nerve, passed through this compartment and was heavily stained with simulated local anaesthetic. Resistance to the passage of the short bevel needle was provided by the lateral glossoepiglottic fold, not the thyrohyoid membrane as we had expected. Of 40 injections, 39 were deemed successful for a success rate of 97.5%. We conclude that this is a simple and highly successful technique for performing superior laryngeal nerve anaesthesia.

Haemoglobin Hammersmith precludes monitoring with conventional pulse oximetry

We report a case of a 15-yr-old North American Indian female with haemoglobin Hammersmith, scheduled for elective tonsillectomy, whose arterial oxygen saturation could not be reliably monitored perioperatively because of technical limitations of conventional dual wavelength pulse oximetry. The patient was chronically icteric. She had an atrial septal defect with a small L-->R shunt demonstrated by echocardiography. On arrival in the operating room pulse oximetry (Nellcor-Model N100) demonstrated a saturation of 45% whilst breathing room air. Her oxygen saturation increased to 60% whilst breathing 100% oxygen via a face mask. An arterial blood gas performed whilst breathing 100% oxygen revealed a PaO2 of 418 mmHg. Tonsillectomy was completed uneventfully under general anaesthesia. The pulse oximeter did not provide any clinically useful information throughout the case. In conclusion, conventional dual wavelength pulse oximeters cannot give an accurate estimate of oxygenation in patients with haemoglobin Hammersmith. Assessment of oxygenation in these patients requires alternative monitoring techniques.

Can parturients distinguish between intravenous and epidural fentanyl?

We tested the hypothesis that the sedative, euphoric, and analgesic effects of intravenous fentanyl would distinguish intravenous from epidural administration. One hundred ASA I and II labouring parturients received 100 micrograms fentanyl either iv or via an epidural catheter in a double-blind, randomized, cross-over fashion. Nineteen anaesthetists (8 staff and 11 residents) participated and correctly guessed the route of administration of the fentanyl in 61/66 intravenous doses and in 69/75 epidural doses yielding a sensitivity of 92.4%, a specificity of 92.0%, a positive predictive value of 91.0%, and a negative predictive value of 93.2%. Of the 41 patients that were crossed over, 38 (92.7%) were able to detect a difference between the routes of administration. Most patients experienced prompt, short-lived symptoms with iv fentanyl but no important differences in fetal heart rate pattern or in maternal desaturation were seen between the groups. This study suggests that subjective symptoms will accurately distinguish intravenous from epidural fentanyl administration in labouring parturients (P < 0.001), and should serve as a safe and reliable intravenous test dose for epidural anaesthesia in the obstetric population.

Temporal changes in left ventricular function after massive sympathetic nervous system activation

Intense activation of the sympathetic nervous system (SNS) decreases the contractile state of the rabbit left ventricle (LV). In this study, we determined the time course of LV dysfunction after massive central activation of the SNS in dogs. Veratrine (40-80 micrograms/kg) was injected intracisternally to activate the SNS in six chloralose-anesthetized dogs, and LV end-diastolic pressure (LVEDP), cardiac output, heart rate, and aortic pressure (Pa) were measured at 30-min intervals for 3 h. Pa increased from 147 +/- 8 (SE) to 272 +/- 7 mmHg (1 mmHg = 133.3 Pa) within 15 min, then declined to 148 +/- 16 mmHg by 1 h LV function curves (stroke work versus LVEDP or stroke work verus LV transmural pressure) showed a marked decrease in slope and a shift to the right within minutes after activating the SNS, which persisted for the duration of the experiment. These data indicate that LV contractility was diminished in these animals. No changes in LV function were observed in three dogs serving as time-matched controls. In three additional dogs, LV pressure was raised to a degree similar to that observed after SNS activation by constricting the ascending aorta for 1 h. These animals exhibited only modest shifts in the LV function curve during and after aortic constriction. Mean plasma catecholamine concentration increased by one to two orders of magnitude in animals after SNS activation, but only minor changes were observed in the other two groups. We conclude that myocardial contractility declines markedly soon after massive SNS activation and is not solely a function of the initial hypertensive period.

The femoral 3-in-1 block revisited

STUDY OBJECTIVE

To estimate the frequency of successful conduction blockade of the femoral, lateral femoral cutaneous, and obturator nerves following a femoral 3-in-1 block.

DESIGN

Prospective observational study.

SETTING

Operating room at Royal University Hospital, Saskatoon, Saskatchewan.

PATIENTS

32 patients having lower extremity surgery.

INTERVENTIONS

Femoral 3-in-1 nerve blocks were performed on all patients.

MEASUREMENTS AND MAIN RESULTS

Sensation and motor power in all 3 nerve distributions (femoral, lateral femoral cutaneous, obturator) were assessed before and after each femoral 3-in-1 nerve block. By our criteria, the femoral nerve block was successful in 26 of 32 patients (81%). The lateral femoral cutaneous nerve was successfully blocked in 25 of 26 patients (96%). Incidentally, the saphenous nerve which is classically described as the terminal branch of the femoral nerve, was successfully blocked in 20 of 26 patients (77%). The obturator nerve block was successful in only 1 of 26 patients (4%).

CONCLUSIONS

The femoral 3-in-1 nerve block does not block the parent trunk of the obturator nerve.

Transsartorial approach for saphenous nerve block

Blockade of conduction in the saphenous nerve is important in providing surgical anaesthesia in the lower leg. Unfortunately, previously described techniques have lacked clinical effectiveness in practice. We developed a transsartorial approach for conduction block of the saphenous nerve. We first confirmed its potential clinical utility in 12 cadaveric specimens by demonstrating that the saphenous nerve was consistently stained by injections of methylene blue. Subsequently, we compared the relative rates of successful saphenous nerve block and the extent of conduction block provided by three techniques: (1) transsartorial saphenous nerve block (TSSNB), (2) above knee femoral paracondylar field block (FPFB), and (3) below knee field block (BKFB) of the saphenous nerve in 20 ASA I volunteers. The transsartorial saphenous nerve block proved to be highly successful (80% success rate) and was superior to the other two approaches in providing cutaneous analgesia to pinprick in the saphenous nerve distribution (P < 0.05). The success rates of the BKFB and FPFB were 65% and 40% respectively. A successful block with the transsartorial approach provided complete anaesthesia of the medial malleolus in 94% of subjects whilst the BKFB and FPFB provided complete anaesthesia of the medial malleolus in less than 40% of the successful blocks. We recommend the transsartorial approach for more effective block of the saphenous nerve.

Reevaluation of the sciatic nerve block

BACKGROUND AND OBJECTIVES

Sciatic nerve blocks are perceived as unreliable, technically demanding, and uncomfortable. With strict criteria to define success rates, we designed a study to examine the efficacy of two techniques of sciatic nerve block.

METHODS

All blocks were performed by a novice in sedated patients using an insulated needle and a nerve stimulator.

RESULTS

Overall success with both techniques was 87.5%. One transient neurologic deficit attributed to the sciatic nerve block was observed; otherwise, the technique provided satisfactory anesthesia without complications.

CONCLUSIONS

Patient acceptance was excellent.

Circulating neuropeptide Y does not produce pulmonary hypertension during massive sympathetic activation

We tested the possibility that neuropeptide Y (NPY) may contribute to the pulmonary hypertension that occurs after massive sympathetic activation produced by intracisternal veratrine administration in the chloralose-anesthetized dog. In six dogs, veratrine caused arterial NPY-like immunoreactivity (NPY-LI) to rise from 873 +/- 150 (SE) pg/ml to peak values of 3,780 +/- 666 pg/ml by 60-120 min. (In 3 animals, adrenalectomy significantly reduced the increases in NPY-LI.) In five additional dogs, we infused porcine NPY for 30 min in doses that increased arterial NPY-LI to 8,354 +/- 1,514 pg/ml and observed only minor changes in pulmonary hemodynamics. In three isolated perfused canine left lower lung lobe (LLL) preparations, increasing doses of NPY were administered, producing levels of plasma NPY-LI, at the highest dose, that exceeded those observed after veratrine administration by three orders of magnitude. No changes in LLL arterial or double-occlusion capillary pressures were observed at any dose. Similarly, no changes in LLL hemodynamics were observed in three additional lobes when NPY was administered while norepinephrine was being infused. We conclude that it is unlikely that NPY plays a role as a circulating vasoactive agent in producing the pulmonary hypertension and edema that occur in this model.