The Role of the Multiparametric MRI LiverMultiScanTM in the Quantitative Assessment of the Liver and Its Predicted Clinical Applications in Patients Undergoing Major Hepatic Resection for Colorectal Liver Metastasis

Liver biopsy remains the gold standard for the histological assessment of the liver. With clear disadvantages and the rise in the incidences of liver disease, the role of neoadjuvant chemotherapy in colorectal liver metastasis (CRLM) and an explosion of surgical management options available, non-invasive serological and imaging markers of liver histopathology have never been more pertinent in order to assess liver health and stratify patients considered for surgical intervention. Liver MRI is a leading modality in the assessment of hepatic malignancy. Recent technological advancements in multiparametric MRI software such as the LiverMultiScanTM offers an attractive non-invasive assay of anatomy and histopathology in the pre-operative setting, especially in the context of CRLM. This narrative review examines the evidence for the LiverMultiScanTM in the assessment of hepatic fibrosis, steatosis/steatohepatitis, and potential applications for chemotherapy-associated hepatic changes. We postulate its future role and the hurdles it must surpass in order to be implemented in the pre-operative management of patients undergoing hepatic resection for colorectal liver metastasis. Such a role likely extends to other hepatic malignancies planned for resection.

Observation versus intervention for incidental common bile duct stones at intraoperative cholangiogram: a systematic review

BACKGROUND

The natural history of incidental common bile duct stones (CBDS) is poorly understood. Current evidence is conflicting, with several studies suggesting the majority may pass spontaneously. Despite this, guidelines recommend routine removal even if asymptomatic. This study aimed to systematically review the outcomes of expectant management for CBDS detected on operative cholangiography during cholecystectomy.

METHODS

MEDLINE, Embase and CINAHL databases were systematically searched. Participants were adult patients with CBDS identified by intraoperative cholangiography. Intervention was regarded as any perioperative effort to remove common bile duct stones, including endoscopic retrograde cholangiopancreatography (ERCP), laparoscopic and open bile duct exploration. This was compared to observation. Outcomes of interest included rates of spontaneous stone passage, success of duct clearance and complications. Risk of bias was assessed using the ROBINS-I tool.

RESULTS

Eight studies were included. All studies were non-randomized, heterogeneous and at serious risk of bias. In patients observed after a positive IOC, 20.9% went on to have symptomatic retained stones. In patients directed to ERCP for positive IOC, persistent CBDS were found in 50.6%. Spontaneous passage was not associated with stone size. Meta-analysis is dominated by the results from one large database, which recommends intervention for incidental stones, despite low rates of persistent stones seen at postoperative ERCP.

CONCLUSIONS

Further evidence is required before a definitive recommendation on observation can be made. There is some evidence that asymptomatic stones may be safely observed. In clinical scenarios where the risks of biliary intervention are considered high, a conservative strategy could be more widely considered.

HPB P68 Multimetric MRI detects improved quality of the future liver remnant post-dual vein embolization – a novel finding

Background

Optimisation of the future liver remnant (FLR) is crucial to the safety of extended liver resections. This study aimed to assess volume and quality of the FLR pre- and post-dual vein embolisation (DVE) by MRI, in patients with insufficient FLR, needing major hepatectomy.

Methods

Of 81 patients recruited in a clinical trial (Precision1:NCT04597710), seven consecutive patients with colorectal liver metastases underwent multiparametric MRI (Hepatica®) pre- and post-DVE (right hepatic and portal vein). One patient had DVE after a first-stage hepatectomy. FLR volume, fibro-inflammation map (corrected T1) and fat (proton density fat fraction, PDFF) was determined.

Results

All 7 patients underwent uncomplicated DVE, with significant increase in median(range) %FLR volume at liver surgery [45.7(27.0–57.8)% versus 32.4 (19.5–37.7)%, p=0.016], 46 days (range 28–77) post-DVE. Median(range) FLR cT1 scores reduced post-DVE [747.33 (684–884)ms, versus 771.25(726–945)ms, p=0.047; healthy range<794ms], as did median(range) PDFF scores [3.4 (2–13.25)% versus 6 (1.5–22.5)%, p=0.078; healthy range <5.6%]. No patient developed post-hepatectomy liver failure (PHLF).

Conclusions

This novel, non-invasive and readily accessible MRI technique shows that volume and quality of the FLR improves after DVE. This is a significant step in improving surgical decision making in patients with borderline FLR, preventing PHLF and improving outcomes.

O-L04 Peri-operative thrombophilia in patients undergoing liver resection for colorectal metastases

Background

The risk of major haemorrhage during liver surgery has decreased considerably in the modern era. However, there remains reluctance amongst liver surgeons to give routine peri-operative chemical thromboprophylaxis, either because of the perceived risk of bleeding, or transient post-operative abnormalities in conventional coagulation studies. The aim of this study was to ask whether a defined, homogeneous population of patients undergoing liver resection for colorectal metastases (CRM) were at risk from venous thromboembolism (VTE) prior to surgery, and what the impact of liver resection was on that risk.

Methods

A single-centre prospective observational cohort study comparing pre-, peri- and post-operative haemostasis variables in patients undergoing liver resection for CRM. Patients with cirrhosis, history of VTE or anticoagulated were excluded, as were patients undergoing small wedge, or laparoscopic liver resections. Blood samples for coagulation assays were collected pre-operatively, peri-operatively (after transection) and first post-operative day (13–20 hours post-operatively). Pre- and post-operative Tissue Factor messenger ribonucleic acid (TFmRNA) activation was measured from peripheral blood mononuclear cells (PBMCs) using semi-quantitative polymerase chain reaction (PCR). Patients received peri-operative mechanical thromboprophylaxis until mobile, plus chemical thromboprophylaxis on the first post-operative day, after venesection.

Results

Of 336 hepatectomies performed October 2017-December 2019, 60 resections in 57 patients were recruited. This included 46.7% major resections, with median (interquartile range [IQR]) blood loss 150.0mls (76.3-263.7), no blood transfusions, post-operative VTE events or deaths. Patients were prothrombotic pre-operatively (high factor VIIIC and thrombin generation velocity index), an effect exacerbated post-hepatectomy. Major hepatectomies had a significantly greater drop in Protein C, rise in Factor VIIIC and von Willebrand Factor, versus minor resections (p = 0.001,0.005,0.001 respectively). Patients with transection times greater than median (40minutes), had significantly increased median (IQR) PMBC-TFmRNA expression [1.65 (0.93-2.70)2ddCt], versus quicker transections [0.99 (0.69-1.28)2ddCt, p = 0.020].

Conclusions

These data show the risk of major haemorrhage in elective liver resection in a high volume unit is low and administration of chemical thromboprophylaxis within 13-20 hours of surgery is safe and effective. The study demonstrates that patients with CRM are prothrombotic pre-operatively. Furthermore, this thrombophilia is exacerbated by liver resection, and most marked in patients with longer, more complex operations. These data suggest that chemical thromboprophylaxis should be considered earlier in the patient pathway, and has resulted in a change in practice for the authors.

SP6.1.2 Colorectal Liver Metastases - Novel Assessment Tools for Resectability (The CoNoR Study): Results from an International Questionnaire of Hepatopancreatobiliary Surgeons

Aims

Hepatic resection offers the only chance of cure for colorectal liver metastases (CLM), yet wide variation in resectability decision-making has been demonstrated. This study aims to evaluate the potential value of two novel assessment tools in aiding resectability decision-making: the LiMAx test (hepatic functional capacity) and HepaT1ca interactive pre-operative MR scan (MR-based volumetry and functional assessment).

Methods

This study utilises four workstreams: WS1 systematic review, WS2 international HPB interviews, WS3 international HPB online questionnaire, and WS4 online scenario-based survey to assess change in decision-making resulting from the novel tools. The WS3 questionnaire closed in January 2021; participation was increased by professional association endorsement (AUGIS, GBIHPBA, E-AHPBA, AHPBA, CHPBA, IHPBA).

Results

197 complete responses were received from 37 countries in 6 continents. The clinical scenario in which HPB surgeons found resectability decisions most challenging was post-chemotherapy downsizing, with >90% of respondents agreeing that the following scenarios also present a challenge: recurrent disease post-liver resection, post-portal vein embolisation, and close proximity to major ducts/vessels. Substantial variation was demonstrated in the percentage future liver remnant at which surgeons preferred further investigation in all scenarios. >90% of respondents felt the novel tools would be potentially useful in decision-making; wide-ranging free-text feedback was also provided.

Conclusions

The questionnaire lends support to the previously documented variation in resectability decision-making and confirms international HPB community support for investigation of these novel tools. Response analysis has facilitated the appropriate case selection to best assess their potential utility in the WS4 survey, due to launch this spring.

Quantitative magnetic resonance imaging predicts individual future liver performance after liver resection for cancer

The risk of poor post-operative outcome and the benefits of surgical resection as a curative therapy require careful assessment by the clinical care team for patients with primary and secondary liver cancer. Advances in surgical techniques have improved patient outcomes but identifying which individual patients are at greatest risk of poor post-operative liver performance remains a challenge. Here we report results from a multicentre observational clinical trial (ClinicalTrials.gov NCT03213314) which aimed to inform personalised pre-operative risk assessment in liver cancer surgery by evaluating liver health using quantitative multiparametric magnetic resonance imaging (MRI). We combined estimation of future liver remnant (FLR) volume with corrected T1 (cT1) of the liver parenchyma as a representation of liver health in 143 patients prior to treatment. Patients with an elevated preoperative liver cT1, indicative of fibroinflammation, had a longer post-operative hospital stay compared to those with a cT1 within the normal range (6.5 vs 5 days; p = 0.0053). A composite score combining FLR and cT1 predicted poor liver performance in the 5 days immediately following surgery (AUROC = 0.78). Furthermore, this composite score correlated with the regenerative performance of the liver in the 3 months following resection. This study highlights the utility of quantitative MRI for identifying patients at increased risk of poor post-operative liver performance and a longer stay in hospital. This approach has the potential to inform the assessment of individualised patient risk as part of the clinical decision-making process for liver cancer surgery.

Study protocol: HepaT1ca - an observational clinical cohort study to quantify liver health in surgical candidates for liver malignancies

Background

Accurate assessment of liver health prior to undertaking resectional liver surgery or chemoembolisation for primary and secondary cancers is essential for patient safety and optimal outcomes. LiverMultiScan™, an MRI-based technology, non-invasively quantifies hepatic fibroinflammatory disease, steatosis and iron content. We hypothesise that LiverMultiScan™can quantify liver health prior to surgery and inform the risk assessment for patients considering liver surgery or chemoembolization and seek to evaluate this technology in an operational environment.

Methods/Design

HepaT1ca is an observational cohort study in two tertiary-referral liver surgery centres in the United Kingdom. The primary outcome is correlation between the pre-operative liver health assessment score (Hepatica score - calculated by weighting future remnant liver volume by liver inflammation and fibrosis (LIF) score) and the post-operative liver function composite integer-based risk (Hyder-Pawlik) score.

With ethical approval and fully-informed consent, individuals considering liver surgery for primary or secondary cancer will undergo clinical assessment, blood sampling, and LiverMultiScan™multiparametric MRI before and after surgical liver resection or TACE. In nested cohorts of individuals undergoing chemotherapy prior to surgery, or those undergoing portal vein embolization (PVE) as an adjunct to surgery, an additional testing session prior to commencement of treatment will occur. Tissue will be examined histologically and by immunohistochemistry. Pre-operative liver health assessment scores and the post-operative risk scores will be correlated to define the ability of LiverMultiScan™to predict the risk of post-operative morbidity and mortality. Because technology performance in this setting is unknown, a pragmatic sample size will be used. For the primary outcome, n = 200 for the main cohort will allow detection of a minimum correlation coefficient of 0.2 with 5% significance and power of 80%.

Discussion

This study will refine the technology and clinical application of multiparametric MRI (including LiverMultiScan™), to quantify pre-existing liver health and predict post-intervention outcomes following liver resection. If successful, this study will advance the technology and support the use of multiparametric MRI as part of an enhanced pre-operative assessment to improve patient safety and to personalise operative risk assessment of liver surgery/non-surgical intervention.

Trial registration

This study is registered on ClinicalTrials.gov Identifier: NCT03213314.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-4737-3) contains supplementary material, which is available to authorized users.

International multicentre prospective study on microwave ablation of liver tumours: preliminary results

BACKGROUND

Microwave ablation (MWA) is increasingly utilized in the treatment of hepatic tumours. Promising single-centre reports have demonstrated its safety and efficacy, but this modality has not been studied in a prospective, multicentre study.

METHODS

Eighteen international centres recorded operative and perioperative data for patients undergoing MWA for tumours of any origin in a voluntary Internet-based database. All patients underwent operative MWA using a 2.45-GHz generator with a 5-mm antenna.

RESULTS

Of the 140 patients, 114 (81.4%) were treated with MWA alone and 26 (18.6%) were treated with MWA combined with resection. Multiple tumours were treated with MWA in 40.0% of patients. A total of 299 tumours were treated in these 140 patients. The median size of ablated lesions was 2.5 cm (range: 0.5-9.5 cm). Tumours were treated with a median of one application (range: 1-6 applications) for a median of 4 min (range: 0.5-30.0 min). A power setting of 100 W was used in 78.9% of cases. Major morbidity was 8.3% and in-hospital mortality was 1.9%.

CONCLUSIONS

These multi-institution data demonstrate rapid ablation time and low morbidity and mortality rates in patients undergoing operative MWA with a high rate of multiple ablations and concomitant hepatic resection. Longterm follow-up will be required to determine the efficacy of MWA relative to other forms of ablative therapy.

Long-term results of liver resection for non-colorectal, non-neuroendocrine metastases

INTRODUCTION

The safety and efficacy of liver resection for colorectal and neuroendocrine liver metastases is well established. However, there is lack of consensus regarding long-term effectiveness of hepatic resection for non-colorectal, non-neuroendocrine (NCNN) liver metastases.

METHODS

A review of prospectively collected data of patients undergoing hepatic resection for NCNN liver metastases at two tertiary referral centres in the UK and Australia was undertaken. Survival analysis was used to evaluate the clinical, demographic and operative factors associated with long-term survival.

RESULTS

A total of 114 hepatic resections in 102 patients were performed between 1986 and 2006. Postoperative mortality and morbidity was 0.8% and 21.1%, respectively. At 3 and 5 years overall survival was 56.1% and 38.5%, whereas disease-free survival was 37.2% and 26.5%, respectively. On multivariate analysis, factors associated with poor overall survival were diameter of liver metastasis [<5 cm versus >5 cm: hazard ratio (HR) = 2.83, p = 0.001] and the presence of extrahepatic nodal disease (HR = 3.58, p = 0.001). The type of tumor, the presence of distant extra-hepatic metastases, tumor-free interval, number and distribution of metastases did not effect long-term survival.

CONCLUSION

These results of the present study suggest that liver resection is an effective management option in selected patients with NCNN metastases confined to the liver.

A two-center experience with the exclusive use of laparoscopic transperitoneal nephrectomy for benign renal disease in children

BACKGROUND

This study aimed to evaluate a two-center experience with pediatric transperitoneal laparoscopic nephrectomy, specifically focusing on the outcome parameters of operative time, complication, analgesic requirement, and postoperative stay.

METHODS

This ambispective study was conducted over a 4-year period between May 2001 and May 2005 in two tertiary pediatric surgical centers. Data were prospectively recorded from an in-house expanded medical audit system (EMAS) and a Microsoft Excel database. Information on patient demographics, operative time, complications, analgesic requirement, and length of hospital stay were retrieved and analyzed.

RESULTS

A total of 30 consecutive patients with a mean age of 4.43 years (range, 3 months to 15 years) underwent laparoscopic nephrectomy. All the patients underwent unilateral nephrectomy/nephroureterectomy for multidysplastic kidney (n = 12), reflux nephropathy (n = 13), pelvicoureteric junction obstruction (n = 4), or cystic disease of indeterminate cause (n = 1). The mean operative time was 93 +/- 30 min. The principal hemostatic devices used were the Harmonic Scalpel (20 cases), liga clips (5 cases), and hook diathermy and endoshears exclusively (4 cases). There were no conversions, but the intraoperative complications of bleeding (n = 2), difficult location (n = 1), difficult extraction (n = 1), and requirement for a liver retractor (n = 2) were encountered. An additional five patients had problems in the immediate postoperative period, two of whom went on to have long term difficulties with recurrent urinary tract infections resulting from a residual ureteric stump, which required surgery. Nearly one-third of the patients required morphine for analgesia in the immediate postoperative period, with the figure falling to 20% by day 1. The median postoperative hospital stay was 1 day (range, 0-16 days). At this writing, all the patients remain under surveillance with a mean follow-up period of 2.88 years, and no patients have experienced complications secondary to intraabdominal adhesions.

CONCLUSION

Transperitoneal laparoscopic nephrectomy is technically feasible in most cases of benign renal disease. The intraoperative complications are minimal, and recovery for most is robust. Two-thirds of the patients are discharged within 24 h. In this study, narcotic analgesics were prescribed in about a one-third of all the cases for a limited period. Further problems may be seen when refluxing ureters are incompletely excised. However, the transperitoneal approach does not mitigate against complete excision because the exposure to the pelvis is adequate. At the midterm follow-up assessment, adhesive obstruction was not encountered, confirming this approach as a tenable alternative to other laparoscopic approaches for nephrectomy.

AFM Study of Rubber Compounds

A series of rubber compounds filled with carbon blacks and silica has been studied by atomic force microscopy (AFM). The microdispersion of carbon black aggregates in rubber compounds can be clearly observed. The surface morphology of worn treads after road testing studied by AFM is also reported.

Lack of correlation between failure of gut barrier function and septic complications after major upper gastrointestinal surgery

OBJECTIVE

To determine the influence of abnormal gut barrier function on the risk of septic complications in patients undergoing major resectional surgery for upper gastrointestinal cancer.

SUMMARY BACKGROUND DATA

A failure of the gut mucosal barrier to exclude bacteria and endotoxin from the portal and systemic circulation is incriminated in the development of sepsis and multiple organ failure. Although the experimental data is compelling, corroborative evidence from studies in humans is sparse. This study attempted to correlate both preoperative gut barrier dysfunction and the pattern of change after surgery with septic outcome.

METHODS

Sixty-eight patients undergoing curative resectional surgery for upper gastrointestinal cancer were monitored for 30-day septic morbidity (intraabdominal abscesses/empyema and pneumonia). Intestinal permeability, serum IgM and IgG anti-endotoxin antibodies (EndoCAb), and serum C-reactive protein were measured before surgery and on postoperative days 1 and 7.

RESULTS

Increased intestinal permeability before surgery did not predict septic outcome. Major surgery was associated with increased intestinal permeability and evidence of endotoxin exposure. Comparing sepsis and nonsepsis groups, however, there was no significant difference in intestinal permeability, endotoxin exposure, and the acute phase response after surgery.

CONCLUSIONS

This study demonstrates that gut barrier dysfunction occurs after surgery, but the magnitude of change does not differentiate patients in whom sepsis develops and those in whom it does not. Preoperative increased intestinal permeability had no predictive value for sepsis. This study failed to support the thesis that gut barrier dysfunction is directly linked to sepsis.

Compared with parenteral nutrition, enteral feeding attenuates the acute phase response and improves disease severity in acute pancreatitis

BACKGROUND

In patients with major trauma and burns, total enteral nutrition (TEN) significantly decreases the acute phase response and incidence of septic complications when compared with total parenteral nutrition (TPN). Poor outcome in acute pancreatitis is associated with a high incidence of systemic inflammatory response syndrome (SIRS) and sepsis.

AIMS

To determine whether TEN can attenuate the acute phase response and improve clinical disease severity in patients with acute pancreatitis.

METHODS

Glasgow score, Apache II, computed tomography (CT) scan score, C reactive protein (CRP), serum IgM antiendotoxin antibodies (EndoCAb), and total antioxidant capacity (TAC) were determined on admission in 34 patients with acute pancreatitis. Patients were stratified according to disease severity and randomised to receive either TPN or TEN for seven days and then re-evaluated.

RESULTS

SIRS, sepsis, organ failure, and ITU stay, were globally improved in the enterally fed patients. The acute phase response and disease severity scores were significantly improved following enteral nutrition (CRP: 156 (117-222) to 84 (50-141), p < 0.005; APACHE II scores 8 (6-10) to 6 (4-8), p < 0.0001) without change in the CT scan scores. In parenterally fed patients these parameters did not change but there was an increase in EndoCAb antibody levels and a fall in TAC. Enterally fed patients showed no change in the level of EndoCAb antibodies and an increase in TAC.

CONCLUSION

TEN moderates the acute phase response, and improves disease severity and clinical outcome despite unchanged pancreatic injury on CT scan. Reduced systemic exposure to endotoxin and reduced oxidant stress also occurred in the TEN group. Enteral feeding modulates the inflammatory and sepsis response in acute pancreatitis and is clinically beneficial.

Energetic dysfunction in quinolinic acid-lesioned rat striatum

Impairment of mitochondrial energy metabolism may contribute to the selective neuronal degeneration observed in Huntington's disease and other neurodegenerative disorders. Intrastriatal injection of the excitotoxin, quinolinic acid, produces a pattern of neuronal death similar to that seen in Huntington's disease. However, little is known about the effects of quinolinic acid on striatal energetics. In the present work, time-dependent changes in energy metabolism caused by injection of quinolinic acid into rat striatum were examined. Oxygen consumption by free and synaptic mitochondria was quantified and correlated with the concentrations of nucleotides and amino acids at different times after injection. Compared with saline-treated controls, a decrease in ADP-stimulated (state 3) to basal (state 4) oxygen consumption (respiratory control ratio) by free mitochondria was apparent in quinolinic acid-injected striata as early as 6 h after treatment. No significant changes were seen in nucleotide concentrations at this time. By 12 h after injection, the decline in the respiratory control ratio was more pronounced (45%), and reductions in ATP, NAD, aspartate, and glutamate (30-60%) were also observed. These results show that injection of quinolinic acid in vivo produces progressive mitochondrial dysfunction, which may be a common and critical event in the cell death cascade initiated in Huntington's disease and in animal models of this neurodegenerative disorder. The indicators of mitochondrial function examined in this study, therefore, may be useful in evaluating the efficacy of neuroprotective agents.

Informatics: a physician's view

From bedside to boardroom, physicians are coming on-line to use automated information systems. Physicians are increasingly able to scroll through computer screens to scan images and lab summaries. But they will obtain their most critical data by listening to, observing, and examining patients. Practitioners will be driven in two diagnostic realms by informatics: acute care and chronic care. Training of both internists and surgeons will be enhanced. Nurses will be able to take on more of doctors' work. Telemedicine may eventually reduce patient visits to the office and doctors' trips to the emergency department. Health care system management is strengthened and network message traffic smoothed by informatics, but lack of trust will slow acceptance.

Self-regulation: the true key to success of physician-directed networks

The purpose of regulation is to promote uniformly high quality health care at a reasonable cost. The purpose of self-regulation is to make regulation more acceptable to the network physicians and create an atmosphere of continual improvement in bedside care. Interviews with medical directors of group practices, independent physician associations, managed care plans, national specialty networks, and physician-hospital organizations were used to learn what methods of self-regulation are popular and effective.

Accounting for the transition from inpatient to outpatient surgery

This article reports on some of the factors that have advanced and impeded hospital progress in moving from inpatient to outpatient surgery. Early on, patients, physicians, and hospital administrators all agreed that outpatient surgery had an intuitive appeal. Patients liked it because they didn't have to go in the hospital. Physicians liked it because they could get in and out of the outpatient surgery center more easily than the main hospital operating room. Administrators recognized the inherent appeal of outpatient procedures but were unable or unwilling to switch services from inpatient to outpatient for a variety of reasons. First, empty hospital beds and diminished scope of inpatient operations are a threat to the power of administrators. Moving surgery from inpatient to outpatient settings reduces inhouse operations. Second, reimbursement incentives were definitely in favor of continued inpatient care long after technology was in place for outpatient care. The third and most critical reason was that cost data on outpatient operations were just not available for making decisions on when to move into the outpatient setting. This review of the literature was intended to document the lack of relevant cost-based accounting. Instead, many other factors that more directly slowed progress were encountered. More than anything, this illustrates the erratic course of progress in health care reform.

Cost containment in emergency departments

Traditionally, cost effectiveness has been overlooked in emergency departments because of a mandate to provide emergency care in every community regardless of expense. However, in the current era of managed care, reduced reimbursement, and cost controls, emergency departments are being examined more carefully to determine whether their costs can be contained or even whether they can become profit centers. Detailed billing, cost accounting, enhanced communication among emergency departments within a community, and linking of suburban and inner-city emergency departments are several means by which emergency departments can control costs and raise revenues.

Blood flow and metabolism in vasogenic oedema

The relationship between white matter cerebral blood flow (CBF) and glucose metabolism (LCMRgl) was studied in a plasma infusion model of vasogenic oedema in cats. LCBF as determined by iodoantipyrine was found to be significantly decreased in oedematous white matter (17.3 +/- 1.5 ml/100 gm/min) when compared with contralateral control white matter (24.8 +/- 1.8 ml/100 gm/min). If the values for oedematous brain were corrected for dilution, however, the LCBF averaged 25.3 +/- 1.7 ml/100 gm/min, which was the same as control. LCMRgl was found to be significantly increased in plasma-infused white matter (16.3 +/- 2.2 mumol/100 gm/min), compared with control white matter (10.7 +/- 1.3). This difference remained despite correction for dilution and recalculation of LCMRgl values based on altered kinetic constants found in oedematous brain. A similar increase in LCMRgl was noted with saline infusion oedema. It is concluded that increased tissue water does not alter CBF, but does induce an increase in anaerobic metabolism.

Cerebral blood flow and glucose metabolism in experimental brain edema

The relationship between cerebral blood flow (CBF) and cerebral metabolic rate of glucose (CMRgl) in the white matter was studied in a plasma infusion model of vasogenic edema in cats. Local CBF, as determined by iodoantipyrine testing, was found to be significantly decreased in edematous white matter (mean +/- standard error of the mean: 17.3 +/- 1.5 ml/100 gm/min) when compared with CBF in the contralateral control white matter (24.8 +/- 1.8 ml/100 gm/min). When the values for edematous brain were corrected for dilution, however, the local CBF averaged 25.3 +/- 1.7 ml/100 gm/min, which was similar to the control value. Local CMRgl was found to be significantly increased in plasma-infused white matter (16.3 +/- 2.2 mumol/100 gm/min) compared with that in control white matter (10.7 +/- 1.3 mumol/100 gm/min). This difference remained, despite correction for dilution and recalculation of local CMRgl values based on altered kinetic constants found in edematous brain. A similar increase in local CMRgl was noted with saline-infusion edema. It is concluded that the increased tissue water level does not alter CBF, but does induce an increase in anaerobic metabolism.

A microtiter plate technique for the detection of platelet antibodies and platelet antigen typing

A microtiter plate assay is described for platelet serologic studies. The assay is based on an indirect radiolabeled antiglobulin test. The test was performed in microtiter wells of 400 microliter capacity manufactured to form strips that fit into a standard 96-well carrier. The strips were broken apart and placed into tubes for counting in a gamma counter. The technique does not require fixation of the platelets to the wells. Freshly collected platelets or platelets that have been stored frozen in 5 percent dimethylsulfoxide can be used. Results are presented using the technique for platelet alloantibody identification, platelet antigen typing, and platelet crossmatching.

Otoplasty: Excision of conchal floor cartilage

In 10 consecutive otoplasties, conchal floor cartilage was excised to facilitate rotating prominent ears back against the head. The procedure is most effective in aural prominence due to deep conchae. Cosmetic improvement is as good as that achieved by excision of posterior wall cartilage, and recontouring of the antihelix fold is needed less often. The amount of cartilage to remove is easily determined, matching of asymmetrically prominent ears is simplified, and concha-mastoid sutures can be placed without tension. The corrections have been followed 1-2 years without recurrence of the deformity.

Bioenergetics of acute vasogenic edema

The bioenergetic mechanisms of vasogenic edema were studied by measuring concentrations of adenosine triphosphate (ATP), phosphocreatine (CrP), and lactate in rapidly frozen edematous white matter in cats. When edema was produced using a cold lesion, it was found that both ATP and CrP were reduced to one-half of control values, and that lactate was elevated. When a correction was applied for dilution, however, it was found that high-energy phosphates were equal to control values, and that lactate was even more significantly elevated. This pattern contrasted with that seen in white-matter ischemia, in which CrP is depressed out of proportion to ATP. Finally, it was found that the white-matter lactate-concentration in the plasma infusion model of edema was increased. It is concluded that vasogenic edema induces an increase in lactate, but does not deplete high-energy phosphate compounds in affected white matter.

The effects of cold-induced brain edema and white-matter ischemia on the somatosensory evoked response

The electrophysiological effects of cold-lesion edema and white-matter ischemia were studied in cats by reference to the short-latency somatosensory evoked response. The primary cortical waves were found to be considerably delayed following a period of white-matter ischemia; hosever, cold-lesion edema appeared to have no significant effect on the evoked response. The authors conclude that vasogenic edema does not interfere with axonal functioning by an ischemic mechanism.

Versatility of lumbar transposition flaps in the closure of meningomyelocele skin defects

A simple method for repair of skin defects after neurosurgical ablation of meningomyelocele is described. One or two skin flaps adjoining the defect are elevated, the right based superiorly and the left inferiorly. They are then transposed to cover the dural repair, and the donor site is repaired by a split-thickness skin graft. The ability of these flaps to close defects of all sizes is stressed.

Cytotoxic edema produced by 6-aminonicotinamide and its response to therapy

Cytotoxic brain edema was produced in rabbits with intraperitoneal administration of a metabolic inhibitor, 6-aminonicotinamide. Paraplegia, diminished feeding, globally diminished muscle tone, and poor coordination were evident 48 hours after the initial administration of the drug and the electroencephalogram (EEG) was characterized by pronounced slowing and diminished voltage. Cisternal monitoring of intracranial pressure (at a pACO2 of 38 to 42 torr) revealed that it was significantly higher than in controls (p &lt; 0.001). Measurements of phosphocreatine, lactate, and NADH did not differ from control values, but total nicotinamide adenine dinucleotide (NAD+/NADH) showed a significant decrease in the experimental group (p &lt; 0.001). Water content of the gray matter was significantly higher in the experimental group when compared to that in controls (p &lt; 0.001). Mannitol and furosemide produced a significant reduction in intracranial pressure (ICP) (p &lt; 0.001) and lowered the water content of the gray matter (p &lt; 0.001). Both agents improved the slow wave form of the EEG 20 minutes after their administration intravenously in 50% of the animals. Dexamethasone (1 mg/kg) was administered with 6-aminonicotinamide 2 days before the experimental day. In 50% of this group, the behavior and EEG were similar to those of normal rabbits, and on the experimental day ICP was slightly lower than that in untreated animals (p &lt; 0.01). The decrease in water content of the gray matter in the steroid group was significantly less than that produced by mannitol and furosemide.

Meningomyelocele skin defects

Meningomyelocele skin defects in ten newborn infants were closed with bilateral lumbar transposition flaps and split-thickness skin grafts. Eight repairs healed promptly without incident. The superficial layer of the flaps in one patient necrosed and were replaced by skin grafts. One patient died of pneumonia and overwhelming sepsis, though the flaps and grafts were healing without reaction. These flaps were useful, even when small, because their placement could be varied to completely cover the defect.

Macrocheilia due to lymphangiectasia

A case of symmetrical, diffuse macrocheilia due to lymphangiectasia is presented. No primary cause for this case or for many other pathologic forms of macrocheilia has been established. Tranverse mucosal wedge resection of the lip with mucosal advancement, however, is a satisfactory method of treatment.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 1: Pathophysiology, electroencephalography, cerebral blood flow, blood-brain barrier, and neurological function

Cerebral blood flow, electrical activity, and neurological function were studied in rabbits subjected to either 15 minutes of oligemia (20 torr cerebral perfusion pressure) or complete cerebral ischemia produced by cisterna magna infusion. During oligemia, flow was reduced from 68.4 +/- 4.2 ml/100 gm/min to 26.3 +/- 4.4 (p less than .01), and during ischemia animals had no proven flow. By 5 minutes after oligemia or ischemia significant symmetrical hyperemia occurred and there was no evidence of the no-reflow phenomenon. The electroencephalogram became isoelectric significantly later and returned significantly sooner in oligemia than in ischemia. Oligemic animals had earlier and better return of neurological function than their ischemic counterparts, although postinsult hypocapnia improved functional recovery in both groups. These experiments do not support the concept that oligemia is a more severe insult than complete ischemia. In intracranial hypertension produced by this model, the no-reflow phenomenon does not occur.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 3: Brain energy metabolism

The authors studied the effect on cortical metabolites of intracranial hypertension produced by the infusion of mock cerebrospinal fluid into the cisterna magna in rabbits subjected to 15 minutes of cerebral oligemia (20 torr) or 15 minutes of complete ischemia. In both groups high-energy metabolites were exhausted within the first 5 minutes of the 15-minute insult. Significant recovery of the high-energy intermediates occurred within 15 minutes of reperfusion, well before return of electroencephalogram (EEG) activity. Continued reperfusion, during which electrical activity and function were returning, brought only moderate improvement in energy metabolites. In contrast, severe lactic acidosis persisted at least 15 minutes after insult, but was reduced by the time EEG activity returned. At no time were there striking differences in metabolites between the oligemic and ischemic groups. These results indicate that recovery in general, and the significantly earlier recovery of oligemic as compared to ischemic animals, cannot be explained on the basis of energy supply. Whether the persistence of lactic acidosis is an important factor limiting return of function requires further study.

Experimental cerebral oligemia and ischemia produced by intracranial hypertension. Part 2: Brain morphology

The authors studied the morphological sequelae of 15 minutes of cerebral oligemia (20 torr cerebral perfusion pressure) and complete cerebral ischemia produced by raised intracranial pressure in rabbits. Ischemic cell change was present in five of seven ischemic animals; it was most extensive in the striatum and hippocampus, with only a few ischemic nerve cells in the thalamus and neocortex. The brains of control and oligemic animals were normal. These results indicate the following: 1) ischemia is a more severe insult than oligemia; 2) compression ischemia results in a pattern of damage that differs from that produced by other types of ischemia; and 3) the method used to reduce cerebral perfusion pressure is an important factor in determining the pattern and extent of brain damage produced.

Polyethylene sling for procidentia

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