Combined PI3K and MAPK inhibition synergizes to suppress PDAC

Oncogenic KRAS mutations are nearly ubiquitous in pancreatic ductal adenocarcinoma (PDAC), yet therapeutic attempts to target KRAS as well as its target MAPK pathway effectors have shown limited success due to the difficulty to pharmacologically target KRAS, inherent drug resistance in PDAC cells, and acquired resistance through activation of alternative mitogenic pathways such JAK-STAT and PI3K-AKT. While KRAS canonically drives the MAPK signaling pathway via RAF-MEK-ERK, it is also known to play a role in PI3K-AKT signaling. Our therapeutic study targeted the PI3K-AKT pathway with the drug Omipalisib (p110α/β/δ/γ and mTORC1/2 inhibitor) in combination with MAPK pathway targeting drug Trametinib (MEK1/2 inhibitor) or SHP099-HCL (SHP099), which is an inhibitor of the KRAS effector SHP2. Western blot analysis demonstrated that application of Trametinib or SHP099 alone selectively blocked ERK phosphorylation (pERK) but failed to suppress phosphorylated AKT (pAKT) and in some instances increased pAKT levels. Conversely, Omipalisib alone successfully inhibited pAKT but failed to suppress pERK. Therefore, we hypothesized that a combination therapeutic comprised of Omipalisib with either Trametinib or SHP099 would inhibit two prominent mitogenic pathways, MEK and PI3K-AKT, to more effectively suppress pancreatic cancer. In vitro studies demonstrated that both Omipalisib/Trametinib and Omipalisib/SHP099 combination therapeutic strategies were generally more effective than treatment with each drug individually at reducing proliferation, colony formation, and cell migration compared to vehicle controls. Additionally, we found that while combination Omipalisib/SHP099 treatment reduced implanted tumor growth in vivo , the Omipalisib/Trametinib treatment was significantly more effective. Therefore, we additionally tested the Omipalisib/Trametinib combination therapeutic in the highly aggressive PKT (Ptf1a cre , LSL-Kras G12D , TGFbR2 fl/fl ) spontaneous mouse model of PDAC. We subsequently found that PKT mice treated with the Omipalisib/Trametinib combination therapeutic survived significantly longer than mice treated with either drug alone, and more than doubled the mean survival time of vehicle control mice. Altogether, our data support the importance of a dual treatment strategy targeting both MAPK and PI3K-AKT pathways.

Adipose-Tumor Crosstalk contributes to CXCL5 Mediated Immune Evasion in PDAC

Background

CXCR1/2 inhibitors are being implemented with immunotherapies in PDAC clinical trials. Cytokines responsible for stimulating these receptors include CXCL ligands, typically secreted by activated immune cells, fibroblasts, and even adipocytes. Obesity has been linked to poor patient outcome and altered anti-tumor immunity. Adipose-derived cytokines and chemokines have been implicated as potential drivers of tumor cell immune evasion, suggesting a possibility of susceptibility to targeting specifically in the context of obesity.

Methods

RNA-sequencing of human PDAC cell lines was used to assess differential influences on the cancer cell transcriptome after treatment with conditioned media from peri-pancreatic adipose tissue of lean and obese PDAC patients. The adipose-induced secretome of PDAC cells was then assessed by cytokine arrays and ELISAs. Lentiviral transduction and CRISPR-Cas9 was used to knock out CXCL5 from a murine PDAC cell line for orthotopic tumor studies in diet-induced obese, syngeneic mice. Flow cytometry was used to define the immune profiles of tumors. Anti-PD-1 immune checkpoint blockade therapy was administered to alleviate T cell exhaustion and invoke an immune response, while the mice were monitored at endpoint for differences in tumor size.

Results

The chemokine CXCL5 was secreted in response to stimulation of PDAC cells with human adipose conditioned media (hAT-CM). PDAC CXCL5 secretion was induced by either IL-1β or TNF, but neutralization of both was required to limit secretion. Ablation of CXCL5 from tumors promoted an immune phenotype susceptible to PD-1 inhibitor therapy. While application of anti-PD-1 treatment to control tumors failed to alter tumor growth, knockout CXCL5 tumors were diminished.

Conclusions

In summary, our findings show that known adipokines TNF and IL-1β can stimulate CXCL5 release from PDAC cells in vitro. In vivo , CXCL5 depletion alone is sufficient to promote T cell infiltration into tumors in an obese setting, but requires checkpoint blockade inhibition to alleviate tumor burden.

DATA AVAILABILITY STATEMENT

Raw and processed RNAseq data will be further described in the GEO accession database ( awaiting approval from GEO for PRJ number ). Additional raw data is included in the supplemental material and available upon reasonable request.

WHAT IS ALREADY KNOWN ON THIS TOPIC

Obesity is linked to a worsened patient outcome and immunogenic tumor profile in PDAC. CXCR1/2 inhibitors have begun to be implemented in combination with immune checkpoint blockade therapies to promote T cell infiltration under the premise of targeting the myeloid rich TME.

WHAT THIS STUDY ADDS

Using in vitro/ex vivo cell and tissue culture-based assays with in vivo mouse models we have identified that adipose derived IL-1β and TNF can promote tumor secretion of CXCL5 which acts as a critical deterrent to CD8 T cell tumor infiltration, but loss of CXCL5 also leads to a more immune suppressive myeloid profile.

HOW THIS STUDY MIGHT AFFECT RESEARCH PRACTICE OR POLICY

This study highlights a mechanism and emphasizes the efficacy of single CXCR1/2 ligand targeting that could be beneficial to overcoming tumor immune-evasion even in the obese PDAC patient population.

Abstract C060: Adipose-tumor crosstalk alters tumor immune profile by promoting PDAC CXCL5 secretion

Pancreatic ductal adenocarcinoma (PDAC) is a leading cause of cancer death in the US, due to late detection and limited therapeutic options. While the main cause of PDAC remains unknown, obesity has been shown to be a major risk factor. However, the molecular mechanisms behind adipose-tumor crosstalk are still being elucidated. Therefore, understanding the crosstalk between adipose and PDAC is critical for improving therapeutic approaches. We hypothesize that factors secreted by the adipose tissue reprogram pancreatic cancer cells to drive tumor growth and anti-tumor immunity. We observed enhanced proliferation in cells treated with conditioned media made from adipose tissue collected from PDAC [MV1] patients. Subsequent analysis determined that PDAC cells also secrete high levels of CXCL5 in response to stimulation with adipose conditioned media. Pathway analysis of RNA-sequencing data from conditioned-media-treated human PDAC cell lines implicated IL-1β and TNF-α as being involved in the resulting transcript changes. Using recombinant IL-1β, we stimulated CXCL5 secretion from multiple PDAC cell lines. Additionally, we found an enhanced secretion of IL-1β from obese adipose tissue compared to that from lean adipose and, using an anti-IL-1β blocking antibody we were able to partially depress the CXCL5 secretion from cells stimulated with adipose conditioned media. Because CXCL5 is a known neutrophil activating and attracting protein, we used CRISPR to engineer CXCL5 deficient murine PDAC cells. To determine the effect of tumor-derived CXCL5 on PDAC growth and immune recruitment, we orthotopically injected non-targeting-control and CXCL5-KO K8484 cells into wild-type, syngeneic, obese mice. While CXCL5-KO tumors displayed a similar size, we observed a significant change in the tumor immune profile. Despite an increase in the pro-tumorigenic monocytic myeloid derived suppressor cells (MDSCs), we found that the CXCL5-KO tumors exhibited a significantly enhanced CD8+ T cell infiltration. However, a high percentage of these CD8+ T cells were PD-1 positive, implicating an exhausted phenotype. Subsequently, we treated wildtype and CXCL5 deficient PDAC bearing obese mice with an anti-PD-1 antibody to promote T-cell re-activation, which resulted in a significantly reduced growth of the CXCL5 deficient tumors. In conclusion, obesity and adipose derived factors directly induce tumor cells to support immune suppression and drive PDAC progression.

Citation Format: R. McKinnon Walsh, Joseph Ambrose, Bailey A. Bye, Austin E. Eades, Jarrid L. Jack, Mariana T. Ruckert, Appolinaire A. Olou, Fanuel Messaggio, Prabhakar Chalise, Dong Pei, Michael N. VanSaun. Adipose-tumor crosstalk alters tumor immune profile by promoting PDAC CXCL5 secretion [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer; 2022 Sep 13-16; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2022;82(22 Suppl):Abstract nr C060.

Synthetic adiponectin-receptor agonist, AdipoRon, induces glycolytic dependence in pancreatic cancer cells

Obesity creates a localized inflammatory reaction in the adipose, altering secretion of adipocyte-derived factors that contribute to pathologies including cancer. We have previously shown that adiponectin inhibits pancreatic cancer by antagonizing leptin-induced STAT3 activation. Yet, the effects of adiponectin on pancreatic cancer cell metabolism have not been addressed. In these studies, we have uncovered a novel metabolic function for the synthetic adiponectin-receptor agonist, AdipoRon. Treatment of PDAC cells with AdipoRon led to mitochondrial uncoupling and loss of ATP production. Concomitantly, AdipoRon-treated cells increased glucose uptake and utilization. This metabolic switch further correlated with AMPK mediated inhibition of the prolipogenic factor acetyl coenzyme A carboxylase 1 (ACC1), which is known to initiate fatty acid catabolism. Yet, measurements of fatty acid oxidation failed to detect any alteration in response to AdipoRon treatment, suggesting a deficiency for compensation. Additional disruption of glycolytic dependence, using either a glycolysis inhibitor or low-glucose conditions, demonstrated an impairment of growth and survival of all pancreatic cancer cell lines tested. Collectively, these studies provide evidence that pancreatic cancer cells utilize metabolic plasticity to upregulate glycolysis in order to adapt to suppression of oxidative phosphorylation in the presence of AdipoRon.

What is the fate of the cholecystostomy tube following percutaneous cholecystostomy?

INTRODUCTION

Cholecystectomy is the preferred treatment for acute cholecystitis with percutaneous cholecystostomy (PC) considered an alternative therapy in severely debilitated patients. The aim of this study was to evaluate the efficacy and outcomes of PC at a tertiary referral center.

METHODS

We retrospectively reviewed all patients that had undergone PC from 2000 to 2014. Data collected included baseline demographics, comorbidities, details of PC placement and management, and post-procedure outcomes. The Charlson comorbidity index (CCI) was calculated for all patients at the time of PC.

RESULTS

Four hundred and twenty-four patients underwent PC placement from 2000 to 2014, and a total of 380 patients had long-term data available for review. Within this cohort, 223 (58.7 %) of the patients were male. The mean age at the time of PC placement was 65.3 ± 14.2 years of age, and the mean CCI was 3.2 ± 2.1 for all patients. One hundred and twenty-five (32.9 %) patients went on to have a cholecystectomy following PC placement. Comparison of patients who underwent PC followed by surgical intervention revealed that they were significantly younger (p = 0.0054) and had a lower CCI (p < 0.0001) compared to those who underwent PC alone.

CONCLUSIONS

PC placement appears to be a viable, long-term alternative to cholecystectomy for the management of biliary disease in high-risk patients. Old and frail patients benefit the most, and in this cohort PC may be the definitive treatment.

Two randomized, double-blind, placebo-controlled, dose-escalation phase 1 studies evaluating BTH1677, a 1, 3-1,6 beta glucan pathogen associated molecular pattern, in healthy volunteer subjects

BACKGROUND

BTH1677 is a beta glucan pathogen associated molecular pattern (PAMP) currently being investigated as a novel cancer therapy. Here, the initial safety and pharmacokinetic (PK) results of BTH1677 in healthy subjects are reported.

SUBJECTS AND METHODS

In the Phase 1a single-dosing study, subjects were randomized (3:1 per cohort) to a single intravenous (i.v.) infusion of BTH1677 at 0.5, 1, 2, 4, or 6 mg/kg or placebo, respectively. In the Phase 1b multi-dosing study, subjects were randomized (3:1 per cohort) to 7 daily i.v. infusions of BTH1677 at 1, 2, or 4 mg/kg or placebo, respectively. Safety and PK non-compartmental analyses were performed.

RESULTS

Thirty-six subjects (N = 24 Phase 1a; N = 12 Phase 1b) were randomized to treatment. No deaths or serious adverse events occurred in either study. Mild or moderate adverse events (AEs) occurred in 67% of BTH1677-treated subjects in both studies. Treatment-related AEs (occurring in ≥10% of subjects) included dyspnea, flushing, headache, nausea, paraesthesia, and rash in Phase 1a and conjunctivitis and headache in Phase 1b. BTH1677 serum concentration was linear with dose. Clearance, serum elimination half-life (t1/2) and volume of distribution (Vss) were BTH1677 dose-independent. In Phase 1b, area under the curve, t1/2, and Vss values were larger at steady state on days 6-30 versus day 0.

CONCLUSIONS

BTH1677 was well tolerated after single doses up to 6 mg/kg and after 7 daily doses up to 4 mg/kg.

Improved quality of life following total pancreatectomy and auto-islet transplantation for chronic pancreatitis

BACKGROUND

Total pancreatectomy (TP) with auto-islet transplant (AIT) is an extreme treatment for chronic pancreatitis, and we reviewed our experience to assess the impact on quality of life (QOL).

METHODS

A prospective cohort study from 2007 through 2010 with pre- and postoperative assessments of the Depression Anxiety Stress Scale, Pain Disability Index, and visual analogue pain scale was performed.

RESULTS

Twenty patients underwent TP-AIT with a median follow-up of 12 months (6.75-24 months). All patients reported moderate (45 %) to severe (55 %) pain prior to surgery. TP-AIT resulted in significant decreases in abdominal pain (p < 0.001), 80 % reporting no or mild pain. Despite pain improvement, only 30 % discontinued narcotics. Improvements in all PDI QOL domains improved from 79 to 90 % (p = 0.002), with greatest improvements seen in those without prior pancreatic surgery, younger patients, and in those with higher levels of preoperative pain. Patients were less affected by depression and anxiety prior to surgery, but 60 and 70 % did show improvement in depression and anxiety, respectively (p = 0.033). Sixteen patients (80 %) required exogenous insulin at last follow-up (mean total dose of insulin 11.6 U/day).

CONCLUSIONS

TP-AIT significantly improves pain and QOL measures in appropriately selected patients with CP.

Laparoscopic robotic-assisted pancreaticoduodenectomy: a case-matched comparison with open resection

BACKGROUND

Minimally invasive procedures have expanded recently to include pancreaticoduodenectomy (PD), but the efficacy of a laparoscopic robotic-assisted approach has not been demonstrated. A case-matched comparison was undertaken to study outcomes between laparoscopic robotic approach (LRPD) and the conventional open counterpart (OPD).

METHODS

From March 2009 through December 2010, 30 LRPD were performed by two pancreaticobiliary surgeons at the Cleveland Clinic. Thirty OPD patients operated by four pancreaticobiliary surgeons during this same period were matched by demographics, and postoperative outcomes were compared from review of a prospectively collected database.

RESULTS

Mean age was 62 years for LRPD versus 61 years for OPD (p = 0.43). Mean body mass index was 24.8 versus 25.6 kg/m(2) (p = 0.49). Surgical indications included adenocarcinoma in 14 patients from each group (46%), intraductal papillary mucinous neoplasm in 4 (14%), and other in 12 (40%). There was one preoperative death in the LRPD group and none following OPD. Morbidity occurred in nine patients (30%) following LRPD versus 13 (44%) in the OPD group (p = 0.14). Intraoperative factors assessed included blood loss (485.8 vs 775 ml, p = 0.13) and operative time (476.2 vs 366.4 min, p = 0.0005). Conversion from LRPD to open occurred in three patients (12%) due to bleeding. Reoperation was performed in two patients (6%) following LRPD versus seven (24%) following OPD (p = 0.17). Length of hospital stay was 9.79 days for LRPD versus 13.26 days in the OPD group (p = 0.043).

CONCLUSIONS

This is the first comparison of a novel laparoscopic robotic-assisted PD with the open PD in a case-matched fashion. Our data demonstrate a significant increase in operative time but decreased length of stay for LRPD. The favorable morbidity following LRPD makes it a reasonable surgical approach for selected patients requiring PD.

Somatostatin therapy for glomus tumors: a report of two cases

Glomus tumors of the head and neck are benign vascular lesions that often provide dilemmas in management. The presence of somatostatin receptors on the tumor cell surface has facilitated an additional imaging technique in the form of radiolabeled octreotide scanning. The use of the somatostatin analogue, octreotide, also provides a therapeutic option for inoperable or recurrent tumors. We present two patients, one with a surgically inaccessible tumor that recurred after primary radiotherapy and one who underwent incomplete resection because of the tumor's proximity to the internal carotid artery. Neither tumor has shown further growth 5 and 3 years after treatment with octreotide, respectively.

Comparison of laparoscopic versus open liver tumor resection: a case-controlled study

BACKGROUND

Although there are data in the literature about the safety and efficacy of laparoscopic liver resections, there are not many studies comparing laparoscopic versus open approaches in a case-matched design. The purpose of this study is to compare the perioperative outcome of laparoscopic versus open liver resections from a single institution.

METHODS

Thirty-one patients underwent laparoscopic liver resection between April 1997 and August 2007, with a prospective laparoscopic program started in April 2006 (n=25). This group of patients was compared with 43 consecutive patients undergoing open resection who were matched by size of the lesion (5 cm or less for malignant and 8 cm or less for benign), anatomical location (segments 2, 3, 4b, 5, 6), and type of resection (wedge resection, segmentectomy, partial liver resection). Data were obtained from medical records as well as from a prospective database. Statistical analysis was performed using t-test and chi-square. All data are expressed as mean +/- standard error on the mean (SEM).

RESULTS

Mean age in the laparoscopic group was 57.6+/-2.7 years versus 61.9+/-2.3 years in the open group (p=0.2). There were more women in the laparoscopic group [74% females (n=23) and 26% males (n=8)] versus in the open group [40% females (n=17) and 60% males (n=26)] (p=0.003). There were more patients with malignant lesions in the open group (73%) versus in the laparoscopic group (45%) (p=0.01). Eight patients underwent partial and 23 patients segmental/wedge liver resection in the laparoscopic group versus 15 patients who underwent partial and 28 patients segmental/wedge liver resection in the open group (p=0.7). Mean tumor size was 3.9+/-0.4 cm in the laparoscopic group versus 4.2+/-0.3 cm in the open group (p=0.5). Ten (32%) out of 31 cases in the laparoscopic group were hand-assisted. Inflow occlusion was used in 1 case (3%) in the laparoscopic group versus 16 (37.2%) in the open group. Mean operating time was 201+/-15 min for the laparoscopic group and 172+/-12 min for the open group (p=0.1). Mean estimated blood loss during the procedure was 122.5+/-45.4 cc for the laparoscopic group and 299.6+/-33.6 cc for the open group (p=0.002). Surgical margin was similar for malignant cases in both groups. Mean hospital stay was 3.2+/-1.0 days for the laparoscopic group and 6.8+/-0.7 days for the open group (p=0.004). The incidence of postoperative complications was 13% (n=4) in the laparoscopic and 16% (n=7) in the open group (p=0.7).

CONCLUSION

This study shows that, with a longer operative time, the laparoscopic approach, despite the learning curve, offers advantages regarding operative blood loss, postoperative analgesic requirement, time to regular diet, hospital stay, and overall cost compared with the open approach for minor liver resections.

Day of surgery admission--is this safe practise?

Day of surgery admission (DOSA) describes the process whereby patients are admitted to hospital and have surgery, on the same day. This is the current admission policy in our institution, for most elective Otolaryngology Head and Neck Surgery patients. We audited 75 consecutive patients admitted on the same day as surgery within our department between May 2006 and January 2007. Significant comorbidity was seen in 28 patients (37.3%). Preoperative investigations prior to surgery were conducted in 64 patients (85.3%). About 21 patients (28%) were delayed going to theatre and the average length of delay was 51 mins. Our cancellation rate was 5.3%. Hospital management have embraced the concept of DOSA in our institution without evaluating the risk to patients. If the DOSA policy is to continue it is imperative that an adequate preoperative assessment clinic is established to prevent negative outcomes for our patients.

Distribution of interstitial cells of Cajal and nitrergic neurons in normal and diabetic human appendix

The objective of this study was to determine the distribution of enteric nerves and interstitial cells of Cajal (ICC) in the normal human appendix and in type 1 diabetes. Appendixes were collected from patients with type 1 diabetes and from non-diabetic controls. Volumes of nerves and ICC were determined using 3-D reconstruction and neuronal nitric oxide synthase (nNOS) expressing neurons were counted. Enteric ganglia were found in the myenteric plexus region and within the longitudinal muscle. ICC were found throughout the muscle layers. In diabetes, c-Kit positive ICC volumes were significantly reduced as were nNOS expressing neurons. In conclusion, we describe the distribution of ICC and enteric nerves in health and in diabetes. The data also suggest that the human appendix, a readily available source of human tissue, may be useful model for the study of motility disorders.

Induction of nasal hyper-responsiveness by allergen challenge in allergic rhinitis: the role of afferent and efferent nerves

BACKGROUND

Hyper-responsiveness of nasal secretory function and volume changes are features of allergic rhinitis (AR) that are mediated in part by neural mechanisms. The finding of nasal hyper-responsiveness in subjects with AR who are currently symptomatic, but not in those who are currently out of season and asymptomatic, suggests that induction of neural reflexes in allergic subjects occurs as a result of allergic inflammation.

OBJECTIVES

To investigate whether allergen exposure in subjects with asymptomatic seasonal allergic rhinitis (SAR) may lead to induction of neural reflexes, and to investigate the components of the reflexes involved in this induction.

METHODS

Asymptomatic subjects with (out-of-season) SAR underwent a nasal bradykinin challenge, before and 24 h after preceding ipsilateral (n = 11) and contralateral (n = 11) antigen challenge. Challenges were performed and nasal secretions collected using filter paper disks, and changes in nasal minimal cross-sectional area (A(min)) were measured using acoustic rhinometry.

RESULTS

Preceding ipsilateral antigen challenge led to the induction of a contralateral secretory reflex (P = 0.01), which was absent in control experiments (P = 0.34). Ipsilateral secretion weights were also enhanced. Preceding contralateral antigen challenge also induced a contralateral secretory reflex (P = 0.03). Enhancement of the reduction in contralateral A(min) was also seen (P = 0.02). Ipsilateral responses were unchanged.

CONCLUSIONS

Allergen exposure in asymptomatic allergic subjects leads to induction of neural reflexes, resulting in nasal hyper-responsiveness, which persists beyond the resolution of the acute allergic response. Our data suggest that the mechanisms of allergen-induced hyper-responsiveness involve both afferent and efferent components.

Conservative management of vestibular schwannomas - second review of a prospective longitudinal study

Vestibular schwannomas have been traditionally managed with microsurgical removal and in recent years, stereotactic radiotherapy. However, there is a group of patients in whom a conservative management approach might represent a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. This is a prospective cohort review of a previously published group of patients [Clin. Otolaryngol. (2000) 25, 28-39] with unilateral vestibular schwannoma that were initially analysed at our institution in 1998 [Walsh R.M., Bath A.P., Bance M.L. et al., Clin. Otolaryngol. (2000) 25, 28]. The mean duration of follow-up was 80 months (range 52-242 months). All the patients in the study underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of rapid radiological tumour growth and/or increasing signs and symptoms, which necessitated active intervention. The mean tumour growth rate for the entire group at the second review was 1 mm/year (range -0.84-9.65 mm/year). The mean growth rate for cerebellopontine angle tumours (1.3 mm/year) was significantly greater than that of internal auditory canal (IAC) tumours (0 mm/year) (P = 0.005). The majority of tumours (87.14%) grew <2 mm/year. There was significant tumour growth seen in 38.9%, no or insignificant growth in 41.7%, and negative growth in 19.4%. Twenty-three patients (32%) failed conservative management at the second review. There was no difference in the outcome of these failed patients in comparison with patients who underwent primary treatment without a period of conservative management. The mean growth rate of tumours in patients that failed conservative management (3.1 mm/year) was significantly greater than that in patients who did not fail (0.2 mm/year) (P < 0.001). No factors predictive of tumour growth or failure of conservative management were identified. Hearing deterioration with pure tone averages (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred irrespective of tumour growth. This prospective study further emphasizes the role of conservative management in selected cases of vestibular schwannomas. Tumours in this study confined to the IAC typically demonstrated minimal or no growth on serial MRI scanning. Regular follow-up with interval scanning is mandatory in all patients.

Laparoscopic splenectomy for lymphoproliferative disease

BACKGROUND

Elective laparoscopic splenectomy (LS) achieves excellent results for benign hematologic diseases. The role of LS for hematologic malignancies is harder to define owing to associated splenomegaly and patient disease that may alter outcome.

METHODS

Retrospective review of single institution experience 1996 through 2002. To limit variability of disease processes, only patients with immune thrombocytopenic purpura (ITP) and lymphoproliferative disease (LPD) were studied.

RESULTS

A total of 211 LS have been performed, including 73 for LPD and 86 for ITP. Patients with LPD were significantly older, 61 vs 46 years p<0.001; male, 45 (62%) vs 33 (38%), p<0.001; and larger splenic weight, 680 vs 162 g, p<0.001. Fifty-nine patients (81%) with LPD were operated with standard LS with a conversion rate of 15%. Hand-assisted LS was performed in 14 patients (19%), and three were converted to open. Compared to ITP, patients with LPD had longer operative time, 148 vs 126 min, p<0001, and higher blood loss, 200 vs 100 cc, p = 0.004. There was one mortality (0.6%), and morbidity occurred in six patients (8%) with LPD and seven (8%) with ITP. The median length of stay was 3 days for LPD and 2 days for ITP, p = 0.03. Forty-six patients were principally operated for a diagnosis, and 27 (60%) were found to have lymphoma.

CONCLUSIONS

LS can be performed safely in patients with LPD, and when used judiciously with hand-assisted techniques can be performed with low conversion and morbidity rates. Splenectomy plays an important role in establishing the diagnosis of lymphoma in LPD.

Imaging for the diagnosis and staging of periampullary carcinomas

Multiple imaging modalities are available for investigating patients with a suspected periampullary neoplasm. The relative utility of each imaging modality is discussed regarding its role in diagnosis and staging. A general imaging approach to patients with a distal biliary obstruction also is presented.

Determination of intact splenic weight based on morcellated weight

BACKGROUND

Comparisons of splenic size based on splenic weight are difficult after laparoscopic splenectomy, which results in a morcellated specimen. We report the results of a direct comparison between morcellated and intact splenic weights.

METHODS

Porcine spleens were harvested via a midline laparotomy, and an intact splenic weight was obtained, which served as the control. The spleen then was placed into an impermeable retrieval bag and returned to the peritoneal cavity. A separate 10-mm incision was made and the spleen mechanically morcellated with a uterine forceps. This design most faithfully recreates the morcellation process during laparoscopic splenectomy in humans. The aggregate weight of the fragments was compared with intact splenic weight.

RESULTS

Intact and morcellated weights were obtained from 58 porcine spleens. The mean intact splenic weight was 145 g, and the mean morcellated weight was 78 g. For a given morcellated weight achieved at laparoscopic splenectomy, an estimated intact weight can be determined by the following formula: intact weight (g) = morcellated weight (g) x 1.34 + 45.

CONCLUSIONS

On the basis of our calculations, a normal spleen weighing 150 g would have a mean morcellated weight of 78 g, and splenomegaly (intact spleen weighing 250 g or more) would be defined by a morcellated weight exceeding 153 g.

Recurrence after laparoscopic ventral hernia repair

BACKGROUND

Although the early results of laparoscopic ventral hernia repair have shown a low recurrence rate, there is a paucity of long-term data. This study reviews a single institution's experience with laparoscopic ventral hernia repair (LVHR).

METHODS

We carried out a retrospective analysis of all LVHR performed at the Cleveland Clinic Foundation from January 1996 to March 2001. Recurrence rates were determined by physical exam or telephone follow-up. Factors predictive of recurrence were determined using Cox regression.

RESULTS

Of 100 ventral hernias completed laparoscopically, 96 were available for long-term follow-up (average, 30 months; range 4-65). There were no deaths and major morbidity occurred in seven patients. Recurrences were identified in 17 patients. Nine recurrences occurred in the 1st postoperative year; however, hernia recurrence continued throughout the period of follow-up. Multivariate analysis showed that a prior failed hernia repair was associated with a more likely chance of another recurrence (65% vs 35%, odds ratio (OR) 3.6; p = 0.05) and that an increased estimated blood loss (106 cc vs 51 cc, OR 1.03; p = 0.005) predicted recurrence. Other variables, including body mass index (BMI) (32 vs 31 kg/m2, p = 0.38), defect size (115 cm2 vs 91 cm2; p = 0.23), size of mesh (468 cm2 vs 334 cm2, p = 0.19), type of mesh (p = 0.62), and mesh fixation (p = 0.99), did not predict recurrence. An additional 14 cases required conversion to an open operation, and seven of these cases (50%) had recurrence on long-term follow-up.

CONCLUSION

Although LVHR remains the preferred method of hernia repair at our institution, this study documents a higher recurrence rate than many other short-term series. There results underscore the importance of long-term follow-up in assessing hernia surgery outcome.

Application of the U and gamma' models in binary sweet taste mixtures

The U and Gamma' models of sensory interactions, successfully applied in olfaction for several years, are tested here using data from published studies on sweetness. The models are subsequently tested on new data obtained in studies of binary mixtures of four sodium sulfamates. The U model allows for the estimation of a global interaction, whereas the Gamma' model allows for the distinction between that which is due to an intrinsic interaction in the mixture itself and that which may be due to the power function exponents in the mixture. The models give satisfactory predictions for observed phenomena of sweet taste suppression, synergism or pure additivity. Additionally, they appear to be more suitable than other models recently applied in taste, particularly the equiratio model. Application of the models to the sulfamate mixtures, reveals additivity for sodium cyclohexylsulfamate (cyclamate)/potassium cyclohexylsulfamate and sodium cyclohexylsulfamate/sodium exo-2-norbornylsulfamate, respectively; whereas for sodium cyclohexylsulfamate/sodium 3-bromophenylsulfamate, the models revealed a slight hypo addition which is simply due to the dissimilarity values of the power function exponents of the components.

Retained gallbladder/cystic duct remnant calculi as a cause of postcholecystectomy pain

BACKGROUND

Pain following cholecystectomy can pose a diagnostic and therapeutic dilemma. We reviewed our experience with calculi retained in gallbladder and cystic duct remnants that present with recurrent biliary symptoms.

METHODS

Over the last 6 years, seven patients were referred to us for the evaluation of recurrent biliary colic or jaundice. There were four men and three women ranging in age from 35 to 70 years. All seven had biliary pain similar to the symptoms that precede cholecystectomy; two of them also had also associated jaundice and one had pancreatitis. The time from cholecystectomy to onset of symptoms ranged from 14 months to 20 years (median, 8.5 Years). Four had undergone laparoscopic cholecystectomy and three had had an open cholecystectomy; none had an operative cholangiogram.

RESULTS

Five of seven underwent diagnostic endoscopic retrograde cholangiography (ERC), which revealed obvious filling defects in the cystic duct or gallbladder remnant. The final patient was diagnosed by laparoscopic ultrasound after eight negative radiographic studies. Four patients underwent laparotomy and resection of a retained gallbladder and/or cystic duct. Two patients were treated with extracorporeal shock-wave lithotripsy (ESWL); one of them also required endoscopic biliary holmium laser lithotripsy. One patient underwent successful repeat laparoscopic cholecystectomy. There were no treatment-related complications. At a median follow-up of 11.5 months, all have achieved complete stone clearance and are asymptomatic.

CONCLUSION

Retained gallbladder and cystic duct calculi can be a source of recurrent biliary pain, and a heightened suspicion may be required to make the diagnosis. This entity can be prevented by accurate identification of the gallbladder-cystic duct junction at cholecystectomy and by routine use of cholangiography. A variety of therapeutic options can be employed to obtain a successful outcome.

Laparoscopic splenectomy

BACKGROUND

Laparoscopic splenectomy is currently the procedure of choice for elective splenectomy. This study reviews the initial 100 laparoscopic splenectomies completed at the Cleveland Clinic Foundation.

METHODS

A retrospective review of elective laparoscopic splenectomy was performed to assess clinical outcomes at the Cleveland Clinic Foundation. Patient demographics, preoperative diagnoses, operative characteristics, morbidity, and mortality were evaluated.

RESULTS

Of the 169 elective splenectomies completed over a 4-year period from 1995 to 1999, 100 were attempted laparoscopically. The proportions of all splenectomies attempted laparoscopically by year were 17%, 38%, 75%, and 72%. Nearly 70% of splenectomies were performed for idiopathic thrombocytopenic purpura or malignancy. Overall, the mean blood loss was 181 ml, and the mean operative time was 170 min. Splenomegaly occurred in 31% of the patients and accounted for longer operative times. Three patients required conversion to an open procedure. Postoperative complications were seen in 13% of the patients. One patient died in the postoperative period from staphylococcal sepsis, giving a mortality rate of 1%.

CONCLUSIONS

Laparoscopic splenectomy currently is the procedure of choice for elective splenectomy at our institution. As compared with traditional open splenectomy, laparoscopic splenectomy results in minimal morbidity even in the setting of splenomegaly.

Laparoscopic vs open resection of gastric stromal tumors

BACKGROUND

Gastric stromal tumors are rare neoplasms that may be benign or malignant. Given that malignant gastric stromal tumors rarely involve lymph nodes and require excision with negative margins, they appear amendable to laparoscopic excision. There are few reports of laparoscopic resection, and no comparisons have been done between laparoscopic and open surgery. This study compares the relative efficacy of the two approaches.

METHODS

Between May 1994 and December 2000, 33 patients underwent 35 operations for gastric stromal tumors. Laparoscopic resections were performed in 21 patients; open resections were done in 12 patients. The medical records of the patients were reviewed retrospectively with regard to operating time, blood loss, length of stay, and clinical course.

RESULTS

Patient demographics, tumor characteristics (mean tumor size, benign vs malignant), and presenting symptoms were similar for both groups. In the laparoscopic group, 15 wedge resections; three partial gastrectomies, and three transgastric needlescopic enucleations were performed. In the open group, six wedge resections, four antrectomies, and two partial proximal gastrectomies were performed. There were no significant differences in mean operative time (169 vs 160 min), mean estimated blood loss (106 vs 129 cc), or perioperative complication rate (9.5% vs 8.3%) between the laparoscopic and open groups, respectively. The mean length of stay was significantly less (p<0.05) in the laparoscopic group (3.8 vs 6.2 days). Average follow-up was 1.5 years. One patient in each group has died due to metastatic disease. There have been no trocar site recurrences.

CONCLUSIONS

Laparoscopic resection of gastric stromal tumors is safe and appropriate. Tumor size, operating time, and estimated blood loss were equivalent to the open approach, and there was a statistically shorter hospital stay in the laparoscopic group.

Outcome of laparoscopic splenectomy based on hematologic indication

BACKGROUND

Laparoscopic splenectomy is the procedure of choice for elective splenectomy at the Cleveland Clinic Foundation. Although the literature clearly documents the technical feasibility and safety of laparoscopic splenectomy, little data exists concerning the results of this procedure based on the hematologic indication for splenectomy. We sought to examine the clinical experience with laparoscopic splenectomy in a single institution, with particular attention to morbidity and clinical outcomes based on hematologic disease process.

METHODS

This study retrospectively reviewed a consecutive series of laparoscopic splenectomies performed for nontraumatic, splenic pathology at the Cleveland Clinic Foundation from August 1995 to January 2001. Patient demographics, operative indications, morbidity, mortality, and clinical outcome were evaluated. Hematologic diagnostic groups were compared using Fisher's exact tests and Wilcoxon rank-sum tests.

RESULTS

A total of 147 laparoscopic splenectomies were performed. Seven patients (5%) required conversion to open splenectomy. Indications for splenectomy included idiopathic thrombocytopenic purpura (ITP) in 65 patients, hematologic malignancy in 43 patients, autoimmune hemolytic anemia (AIHA) in 9 patients, thrombotic thrombocytopenic purpura (TTP) in 9 patients, splenomegaly in 5 patients, splenic cyst in 4 patients, splenic abscess in 3 patients, hereditary spherocytosis in 2 patients, splenic artery aneurysm in 2 patients, Felty's syndrome in 1 patient, myelofibrosis in 1 patient, and other in 3 patients. Accessory spleens were identified in 20 patients (14%). Postoperative complications occurred in 23 (16%) patients. Patients with ITP had significantly shorter operation times (134 vs 163 min; p = 0.001), decreased estimated blood loss (126 vs 307 ml; p = 0.001), decreased length of hospital stay (2.8 vs 4.6 days; p < 0.001), and less chance of conversion (0 vs 7; p = 0.02) than patients with any other diagnosis. A mean follow-up period of 20 +/- 14 months showed an 85% rate of remission for ITP, 89% for TTP, and 89% for AIHA. Patients with malignant disease had significantly larger spleens (822 vs 313 g; p < 0.001), more estimated blood loss (380 vs 168 ml; p = 0.04), and longer operative times (170 vs 142 min; p = 0.009), as compared patients treated for benign disease. However, the length of hospital stay (4.3 vs 3.6 days; p = 0.06) and complication rates (19% vs 14%; p = 0.08) were not significantly different between the two groups.

CONCLUSIONS

When performed for ITP, laparoscopic splenectomy resulted in shorter operations, minimal blood loss, earlier discharge, no conversions, and excellent remission rates, as compared with other hematologic indications. Despite larger spleens, more blood loss, and longer operations in patients with hematologic malignancies, morbidity and length of hospital stay still were similar to those associated with benign indications for laparoscopic splenectomy. In conclusion, laparoscopic splenectomy is safe and efficacious for a multitude of benign and malignant hematologic indications, and our data compares favorably to those for open series.

Laparoendoscopic treatment of gastric stromal tumors

Gastric stromal tumors are the most common submucosal mass found in the stomach. These tumors are most often diagnosed at endoscopy and can be accurately characterized by endoscopic ultrasound. They typically require surgical resection, and an increasing number of patients undergo laparoscopic resection. A combined laparoscopic/endoscopic, intragastric enucleation technique is described, and results are reported in 10 patients. Eleven nonmalignant lesions were excised, with a mean size of 4.12 (2.0 to 7.0) cm. There were no complications, and the median length of stay was 3.5 days. This surgical approach appears appropriate for predominantly intraluminal, benign-appearing lesions of the proximal stomach.

Intracranial complications of acute frontal sinusitis

Despite advances in the diagnosis and treatment of acute frontal sinusitis, there is still significant occurrence of intracranial complications. Urgent surgical evacuation of any intracranial collection is required; however, the surgical management of the associated sinusitis remains controversial. Ten patients presented to this department over a 12-month period with subdural empyema secondary to acute frontal sinusitis. Four patients had a coexisting Pott's puffy tumour and one patient had a periorbital abscess. Each patient was managed using a multidisciplinary approach. A frontal sinus trephine/drain +/- antral washout was performed at the same time as craniotomy with evacuation of the empyema. With this approach only two patients suffered long-term morbidity in our series, in the form of persistent neurological or cognitive deficit. No patient required a definitive sinus procedure. This study emphasizes the need for the early assessment and intervention of patients with an intracranial complication secondary to acute frontal sinusitis. Further assessment of the underlying sinus disease is indicated during outpatient follow up after the acute episode.

Pancreatic complications following laparoscopic splenectomy

BACKGROUND

Laparoscopic splenectomy (LS) has been widely accepted despite a paucity of outcome data. Therefore, we performed a review of LS to assess the pancreatic complications and outcomes associated with this procedure.

METHODS

Ninety-four splenectomies were performed for a variety of hematologic disorders. The patient was placed in the lateral position, and three or four trocars were used.

RESULTS

LS was completed successfully in 93 patients. One case was converted to an open splenectomy for suspected gastrotomy. Thirty of 32 patients with splenomegaly underwent successful LS. Fifteen patients (16%) had some evidence of pancreatic injury. Six patients had asymptomatic hyperamylasemia. An injury directly associated with an adverse outcome occurred in nine cases (9.5% overall); six patients had pancreatic collections, one had a pancreatic fistula, and two developed hyperamylasemia and pain altering the length of hospitalization. Four of these nine patients did not have elevated postoperative amylase levels and were readmitted with pancreatic complications.

CONCLUSIONS

LS can be performed for most pathologic conditions. Pancreatic injury is the most common morbidity associated with LS. The detection of hyperamylasemia can alert the surgeon to a pancreatic injury and alter postoperative management.

Laparoendoscopic treatment of gastric stromal tumors

Gastric stromal tumors are the most common submucosal mass found in the stomach. These tumors are most often diagnosed at endoscopy and can be accurately characterized by endoscopic ultrasound. They typically require surgical resection, and an increasing number of patients undergo laparoscopic resection. A combined laparoscopic/endoscopic, intragastric enucleation technique is described, and results are reported in 10 patients. Eleven nonmalignant lesions were excised, with a mean size of 4.12 (2.0 to 7.0) cm. There were no complications, and the median length of stay was 3.5 days. This surgical approach appears appropriate for predominantly intraluminal, benign-appearing lesions of the proximal stomach.

Laparoscopic splenectomy in patients with normal-sized spleens versus splenomegaly: does size matter?

Laparoscopic resection has become the standard means for removal of normal-sized spleens in many medical centers. The application of minimally invasive techniques in the setting of splenomegaly is less well defined and was previously considered a contraindication to the laparoscopic approach. The purpose of this prospective study of consecutive patients was to compare the outcomes of patients undergoing laparoscopic splenectomy for normal-sized spleens (150 g or less) versus those with clear evidence of splenomegaly (500 g or greater). One hundred forty-two patients met the inclusion criteria. The most common diagnosis in the normal-sized spleen group was idiopathic thrombocytopenia purpura (67 of 82, 82%). Malignant hematologic diseases (lymphoma and leukemia) were the most common diagnoses in the splenomegaly group (35 of 60, 58%). Mean operative times (127 vs 172 minutes) and estimated blood loss (123 vs 173 cm3) were lower for those patients with normal-sized spleens (P < 0.05). There were no statistical differences in conversion rates, lengths of stay, or complications between the two groups. We conclude that laparoscopic splenectomy is safe and effective in the setting of splenomegaly despite modest but statistically longer operative times and increased operative blood loss when compared with laparoscopic splenectomy for normal-sized spleens.

Treatment of intractable epistaxis using arterial embolization

Arterial embolization has become the procedure of choice for managing intractable epistaxis in certain centres in North America and Europe, with arterial ligation reserved for those patients in which it fails. In Ireland, the role of this relatively new technique is poorly defined. The aim of this retrospective study was to investigate the outcome of all patients who underwent arterial embolization for intractable epistaxis in Dublin since it was introduced in 1998. Embolization resulted in complete and immediate resolution of epistaxis in 10 out of 12 patients (82%). Two patients required carotid ligation because of persistent epistaxis. One other patient had a further minor epistaxis 2 days following embolization, which was treated successfully with cautery. No major complications occurred in any of the patients. This study suggests that arterial embolization is an effective and safe method of managing patients with intractable epistaxis.

Partial labyrinthectomy approach for brainstem vascular lesions

Conventional wisdom has typically dictated that the bony labyrinth is an inviolate structure. This notion, however, was successfully challenged following the introduction of the partial labyrinthectomy approach, which was primarily used for the surgical management of cerebellopontine and petrous apex meningiomas. In this article, we discuss an extension of the technique of partial labyrinthectomy in a series of patients that has been used for the treatment of brainstem vascular lesions. We believe that this technique provides superior exposure to the brain stem when compared with conventional retrosigmoid and retrolabyrinthine approaches while reducing the inherent morbidity seen in transotic or petrosectomy approaches.

Loss of interstitial cells of cajal and inhibitory innervation in insulin-dependent diabetes

BACKGROUND & AIMS

Gastrointestinal complications of long-standing diabetes include nausea, vomiting, abdominal pain, diarrhea, and constipation. The pathophysiology underlying these symptoms is poorly understood. Recent evidence suggests an important role for interstitial cells of Cajal in controlling gastrointestinal motility. The aim of this study was to determine changes in interstitial cells of Cajal and enteric innervation in a patient with insulin-dependent diabetes.

METHODS

A full thickness jejunal biopsy was obtained from a 38-year-old insulin-dependent diabetic with evidence for diabetic gastroenteropathy. Immunohistochemistry, confocal microscopy, and 3-dimensional reconstruction techniques were used to quantify changes in the volume of interstitial cells of Cajal and enteric innervation.

RESULTS

Interstitial cells of Cajal were markedly decreased throughout the entire thickness of the jejunum. A decrease in neuronal nitric oxide synthase, vasoactive intestinal peptide, PACAP, and tyrosine hydroxylase immunopositive nerve fibers was observed in circular muscle layer while substance P immunoreactivity was increased.

CONCLUSIONS

The data suggest that long-standing diabetes is associated with a decrease in interstitial cells of Cajal volume and a decrease in inhibitory innervation, associated with an increase in excitatory innervation. The changes in interstitial cells of Cajal volume and enteric nerves may underlie the pathophysiology of gastrointestinal complications associated with diabetes and suggest future therapeutic targets.

Laparoscopic splenectomy for malignant diseases

A variety of malignant diseases involving the spleen, both primary and metastatic, may require splenectomy for diagnosis or therapeutic reasons. The role of minimally invasive surgery in the management of malignant diseases involving the spleen is not well defined because of a lack of reported experience with laparoscopic splenectomy in this group. A reluctance to perform laparoscopic splenectomy in these patients may be explained by the technical and oncological challenges that often accompany malignant splenic diseases such as splenomegaly, perisplenitis, hilar lymphadenopathy, and fear of splenic disruption and tumor spillage. In our experience, the adoption of a lateral technique and the use of hand-assisted devices has allowed for the successful completion of laparoscopic splenectomy for malignant hematologic diseases including spleens up to 28 cm in length and greater than 3 kg morcellated weight. Laparoscopic splenectomy reliably alleviates the symptoms related to splenomegaly and reverses the hematologic abnormalities of hypersplenism. Although laparoscopic splenectomy for malignant diseases is feasible, the role of minimally invasive surgery in the staging of Hodgkin's lymphoma remains undetermined.

Role of differential neuroaxial blockade in the evaluation and management of pain in chronic pancreatitis

OBJECTIVES

Chronic pancreatic pain is difficult to treat. Surgical and medical therapies directed at reducing pain have met with little long-term success. In addition, there are no reliable predictors of response including pancreatic duct diameter. A differential neuroaxial blockade allows characterization of chronic abdominal pain into visceral and nonvisceral pain origins and may be useful as a guide to the treatment. Pain from an inflamed, and scarred pancreas should be visceral in origin. The purpose of our study was to determine the frequency with which patients with chronic pancreatitis have visceral pain and whether our modified differential neuroaxial blockade technique using thoracic epidural analgesia can accurately predict which patients will respond to medical or surgical therapy.

METHODS

We retrospectively reviewed the medical records of patients with a firmly established diagnosis of chronic pancreatitis (Cambridge classification, calcifications) who had undergone a differential neuroaxial block for their chronic abdominal pain evaluation. Patient demographics and medical or surgical treatment for pancreatic pain was recorded. Response to therapy was defined by a 50% reduction in pain by verbal response score.

RESULTS

A total of 23 patients were identified. Alcohol was the most common etiology for chronic pancreatitis (15 of 23, 55%). Surprisingly, the majority of chronic pancreatitis patients had nonvisceral pain (18 of 23, 78%) and only 22% (5 of 23) had visceral pain by differential neuroaxial block. Four of five patients (80%) with visceral pain responded to therapy, whereas only 5 of 17 (29%) of patients with nonvisceral pain responded.

CONCLUSIONS

Surprisingly, patients with chronic pancreatitis commonly have nonvisceral pain. Differential neuroaxial blockade can predict which patients will respond to therapy.

The ascendance of laparoscopic splenectomy

The application of laparoscopic techniques for abdominal procedures has been achieved with varying success. The general acceptance of laparoscopic splenectomy (LS) may be hindered by its infrequent performance and difficulty in manipulating the spleen. A retrospective review of splenectomies performed for primary splenic pathology was done to assess the role and outcome of LS. One hundred fifty LSs were performed from July 1995 through September 1999. Over that time period the proportion of LS performed increased steadily from 17 to 75 per cent of all splenectomies. The primary indications for splenectomy included immune thrombocytopenic purpura in 75 (50%), lymphoma/leukemia 36 (24%), and splenomegaly 19 (13%). There were 86 females and 64 males. Immediately before operation 36 patients (4%) had a platelet count <50,000/ mL, and 24 patients (16%) a hemoglobin <10 mg per cent. The mean operative time was 161 minutes with an average blood loss of 138 cm3 (<50-800). The mean morcellated weight of the entire group was 411 g (33-3300) indicating generally large splenic size. In the 37 patients with splenomegaly the mean weight was 735 g (293-3300). There were two conversions to open splenectomy. Two patients with hematologic malignancy, splenomegaly, and cytopenias died from overwhelming post-splenectomy sepsis (1.3%). Morbidity occurred in 14 (9%) with the most common complication being pancreatitis in seven (5%). The median length of postoperative stay was 2.4 days (range 1-5). In summary LS has rapidly replaced the open approach for nearly all elective splenectomies in adults and children. When performed with the patient in the lateral position it can be accomplished with minimal morbidity, even in complex patients, including those with splenomegaly.

Regeneration of the mammalian vestibular sensory epithelium following gentamicin-induced damage

OBJECTIVES

The aims of this study are (1) to investigate if significant long-term recovery of mature hair bundle (MHB) numbers takes place following gentamicin-induced damage to the mammalian vestibular sensory epithelium and (2) to assess if the different MHB types in the vestibular sensory epithelium have a different susceptibility to ototoxic damage.

METHODS

Gentamicin (8 mg in 0.1-mL sterile water) was injected transtympanically into one ear of guinea pigs, the contralateral ear acting as a control. The animals were killed at 4 days, 4 weeks, and 3 and 10 months post-treatment and the utricles (n = 38) were extracted from both ears. Mature hair bundle and immature-looking hair bundle (IHB) densities on the surface of the utricle were determined using scanning electron microscopy.

RESULTS

The MHB density showed a significant decline between 4 days and 4 weeks post-treatment. There was greater loss of type I MHBs (tallest stereocilia comparable in height to the kinocilium) than type II MHBs (kinocilium taller than the tallest stereocilia). A significant increase in IHB density was seen at 4 weeks post-treatment, after which it declined rapidly. A significant but incomplete recovery in MHB density (to 66% of control value) was seen in the striolar region at 10 months post-treatment, and these were composed mainly of type II MHBs.

CONCLUSIONS

It would appear that the mature mammalian vestibular sensory epithelium does have the capacity for long-term recovery of MHB numbers following gentamicin-induced damage, but this is limited and does not result in complete restoration of the epithelium. Type I MHBs are more susceptible to ototoxic damage than type II MHBs. Sommaire

Comparison of two radiologic methods for measuring the size and growth rate of extracanalicular vestibular schwannomas

OBJECTIVE

To compare two methods for measuring the size and growth rate of extracanalicular vestibular schwannomas: the method recommended in 1995 by the American Academy of Otolaryngology--Head Neck Surgery (AAO-HNS) and the maximum cerebellopontine angle (CPA) tumor diameter, i.e., the method often used in radiologic reports.

STUDY DESIGN

Retrospective clinical study.

SETTING

Tertiary referral center.

PATIENTS

Fifty-four patients with a radiologic diagnosis of unilateral extracanalicular vestibular schwannoma whose tumors were managed conservatively for a mean duration of 39.8 months (range 12-194 months).

INTERVENTION

The extracanalicular component was measured by use of high-resolution magnetic resonance imaging (2- to 3-mm axial slices) at 6- to 12-month intervals.

MAIN OUTCOME MEASURES

Tumor diameter was calculated by two methods. In the AAO-HNS method, the axial image with the largest extracanalicular tumor diameter was selected, and the maximum anteroposterior (A-P) and medial-lateral (M-L) tumor diameters were calculated. The A-P diameter was calculated parallel to the posterior surface of the petrous temporal bone, and the M-L diameter was calculated perpendicular to it. The size of the tumor was calculated as the square root of the product of these two diameters. In the maximum CPA method, the maximum CPA tumor diameter in any direction was also measured.

RESULTS

There was no significant difference between the two methods for measuring the extracanalicular tumor size and growth rate, although the maximum CPA diameter method was consistently greater than the AAO-HNS method. There was a strong positive correlation between the two methods for assessing tumor size and growth. The A-P and M-L extracanalicular tumor diameters also showed a strong positive correlation, suggesting that the extracanalicular portion of vestibular schwannomas tends to enlarge equally in both these directions.

CONCLUSION

There is a strong positive correlation between these two methods for assessing both the tumor size and the growth rate of extracanalicular vestibular schwannomas. However, because vestibular schwannomas tend to grow in both the A-P and the M-L directions, this suggests that the AAO-HNS method is preferable.

The natural history of untreated vestibular schwannomas. Is there a role for conservative management?

OBJECTIVE

The aim of this study was to investigate the natural history and outcome following the conservative management of a group of patients with unilateral vestibular schwannomas.

METHODS

72 patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively because of poor general health, advanced age, patient preference, small tumour size, minimal symptoms, or tumour in the only/better hearing ear. All patients underwent serial magnetic resonance imaging for assessment of tumour growth, according to American Academy of Otolaryngology-Head & Neck Surgery guidelines (1995). The mean duration of follow-up was 37.8 months (range 12-194 months). Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth, and/or increasing symptoms or signs.

RESULTS

The mean tumour growth rate was 1.16 mm/year (range -0.75 to 9.65 mm/year). Approximately 83% of tumours grew at less than 2 mm/year. Significant tumour growth (total growth > 1 mm) was seen in 36.4%, no or insignificant growth (0-1 mm) in 50%, and negative growth (< 0 mm) in 13.6% of tumours. The growth rate of cerebellopontine angle (CPA) tumours (1.4 mm/year) was significantly greater than that of tumours limited to the internal auditory canal (IAC) (0.2 mm/year) (p = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable as those who underwent primary treatment, without a period of conservative management. The growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (p < 0.01). No factors predictive of tumour growth were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not.

CONCLUSIONS

The majority of vestibular schwannomas are slow growing, although, CPA tumours appear to grow faster than IAC tumours. Deterioration of auditory function occurs even in the absence of tumour growth. Although most Otolaryngologists and Neurosurgeons would agree that the treatment of choice for the majority of vestibular schwannomas is microsurgery, there remains a small group of patients in whom a conservative management approach may be a desirable alternative.

Laparoscopic splenectomy for malignant diseases

A variety of malignant diseases involving the spleen, both primary and metastatic, may require splenectomy for diagnosis or therapeutic reasons. The role of minimally invasive surgery in the management of malignant diseases involving the spleen is not well defined because of a lack of reported experience with laparoscopic splenectomy in this group. A reluctance to perform laparoscopic splenectomy in these patients may be explained by the technical and oncological challenges that often accompany malignant splenic diseases such as splenomegaly, perisplenitis, hilar lymphadenopathy, and fear of splenic disruption and tumor spillage. In our experience, the adoption of a lateral technique and the use of hand-assisted devices has allowed for the successful completion of laparoscopic splenectomy for malignant hematologic diseases including spleens up to 28 cm in length and greater than 3 kg morcellated weight. Laparoscopic splenectomy reliably alleviates the symptoms related to splenomegaly and reverses the hematologic abnormalities of hypersplenism. Although laparoscopic splenectomy for malignant diseases is feasible, the role of minimally invasive surgery in the staging of Hodgkin's lymphoma remains undetermined.

Reversible tobramycin-induced bilateral high-frequency vestibular toxicity

We report an unusual case of tobramycin-induced bilateral high-frequency vestibular toxicity with subsequent clinical and objective evidence of functional recovery. In those patients with a clinical presentation suggestive of aminoglycoside-induced bilateral vestibular toxicity (ataxia and oscillopsia) and normal low-frequency (ENG-caloric) responses, high-frequency rotation chair testing should be performed to exclude a high-frequency vestibular deficit.

Sensorineural hearing loss in ulcerative colitis

Sensorineural hearing loss has been described in a small number of patients with ulcerative colitis. At present, it is not known whether this is a rare and sporadic association, or whether these reports represent an under recognised extra-intestinal manifestation of ulcerative colitis. The aim of this study was to determine the prevalence of hearing loss in patients with ulcerative colitis. Twenty patients with active ulcerative colitis (mean age 45 years) were recruited prospectively along with 20 healthy age- and sex-matched controls. Otoscopy, tympanometry and pure tone audiometry were performed. The activity of the disease was scored according to a 12-month cumulative disease activity index. No patients complained of auditory symptoms. Otoscopy and tympanometry were normal in all patients and controls. Pure tone audiometry showed significant sensorineural hearing loss over all frequencies in patients with ulcerative colitis compared with controls. This preliminary study indicates that subclinical sensorineural hearing loss is associated with ulcerative colitis. Further study is warranted to determine the nature of the relationship and its pathological basis.

The mini-laparoscopic intragastric resection of a gastroesophageal stromal tumor: a novel approach

The laparoscopic wedge resection of gastric stromal tumors has been shown to be safe and effective. The removal of these tumors at the gastroesophageal junction is not amenable to a typical local resection because of anatomic inaccessibility and potential luminal restriction after resection. Also, an esophagogastrectomy is not tenable in the setting of benign disease. The recent advances in miniaturized laparoscopic instrumentation (2-mm diameter) have expanded the laparoscopic options, including intraluminal resection. The first intragastric mini-laparoscopic resection of the gastric stromal tumor at the gastroesophageal junction is reported.

The role of conservative management of vestibular schwannomas

Although microsurgery is generally regarded as the conventional treatment of choice for most vestibular schwannomas, there remains a group of patients in whom a conservative management approach may be a desirable alternative. The aim of this study was to determine the natural history and outcome following the conservative management of 72 patients with unilateral vestibular schwannomas. The reasons for conservative management included poor general health, age, patient preference, small tumour size, minimal or no symptoms, and tumour in the only/better hearing ear. The mean duration of follow-up was 39.8 months (range 12-194 months). All patients underwent serial magnetic resonance imaging (MRI) for assessment of tumour growth. Patients were deemed to have failed conservative management if there was evidence of continuous or rapid radiological tumour growth and/or increasing symptoms or signs. The mean tumour growth rate, according to the 1995 guidelines of the American Academy of Otolaryngology/Head and Neck Surgery, was 1.16 mm/year (range: 0.75 9.65 mm/year). Approximately 83% of tumours grew at < 2 mm/year. Significant tumour growth was seen in 36.4%, no or insignificant growth in 50%, and negative growth in 13.6% of tumours. The growth rate of CPA tumours (1.4 mm/year) was significantly greater than that of IAC tumours (0.2 mm/year) (P = 0.001). Failure of conservative management, in which active treatment was required, occurred in 15.3%. The outcome of these patients appeared to be as favourable to a comparable group who underwent primary treatment, without a period of conservative management. The mean growth rate of tumours in patients who failed conservative management (4.2 mm/year) was significantly greater than that in patients who did not fail (0.5 mm/year) (P < 0.01). No factors predictive of tumour growth or failure of conservative management were identified. Deterioration of mean pure tone average (0.5, 1, 2, 3 kHz) and speech discrimination scores occurred regardless of whether radiological tumour growth was demonstrated or not. This study suggests that in a select number of cases of vestibular schwannoma, a conservative management approach may be appropriate. Regular follow-up with serial MRI is mandatory. Deterioration of auditory function occurs even in the absence of tumour growth.

Consequences to hearing during the conservative management of vestibular schwannomas

OBJECTIVE

To estimate the risk of loss of serviceable hearing during the conservative management of vestibular schwannomas.

STUDY DESIGN

Retrospective case review.

METHODS

Twenty-five patients with a radiological diagnosis of unilateral vestibular schwannoma were managed conservatively for a mean duration of 43.8 months (range, 12-194 mo). The pure-tone average (PTA) (0.5, 1, 2, and 3 kHz) and speech discrimination scores (SDS) were measured at regular intervals throughout the entire duration of follow-up. Serviceable hearing was defined using two criteria: 70% SDS/30 dB PTA (the 70/30 rule) and 50% SDS/50 dB PTA (the 50/50 rule). The size and growth rate of tumors were determined according to the American Academy of Otolaryngology-Head and Neck Surgery guidelines (1995). Intervention was recommended if there was evidence of continuous or rapid radiological tumor growth, and/or increasing symptoms or signs suggestive of tumor growth.

RESULTS

The risk of loss of serviceable hearing for the total group was 43% using the 70/30 rule and 42% using the 50/50 rule. Tumor growth was considered significant (> 1 mm) in 8 tumors (32%) and nonsignificant in 17 (68%). The risk of loss of serviceable hearing for the tumor-growth group was 67% using the 70/30 rule and 80% using the 50/50 rule. In contrast, the risk of loss of serviceable hearing for the no tumor-growth group was 25% using the 70/30 rule and 14% using the 50/50 rule. No audiological factors predictive of tumor growth were identified.

CONCLUSIONS

There is a significant risk of loss of serviceable hearing during the conservative management of vestibular schwannomas. This risk appears to be greater in tumors that demonstrate significant growth.

The transmastoid partial labyrinthectomy approach to medial skull base lesions

INTRODUCTION

It has long been thought that surgical disruption of the membranous labyrinth invariably results in sensorineural hearing loss and balance dysfunction. Recent evidence suggests that the inner ear can withstand such manipulation without loss of function. The technique of transmastoid partial labyrinthectomy has recently been described as a means of providing access to lesions of the medial skull base by removing part of the labyrinth and at the same time attempting to preserve hearing and vestibular function of the lateral semicircular canal (LSCC) and otolithic organs.

PROCEDURE

An extended cortical mastoidectomy is performed and the posterior and middle cranial fossa dura are exposed widely. The posterior and superior semicircular canals are occluded at their ampullated ends and at the crus commune, and then resected. The LSCC and vestibule are left undisturbed. The petrous apex is removed and the medial end of the internal auditory canal is exposed. Posterior cranial fossa dural flaps are raised allowing access to the brainstem, petro-clival area and cerebellopontine angle. Temporal and suboccipital craniotomies can be performed, as required.

RESULTS

Four patients underwent this procedure by a joint Otolaryngological-Neurosurgical team for access to the following lesions: three intra-axial pontine cavernomas and a basilar artery aneurysm. The preliminary hearing and balance results are discussed.

CONCLUSIONS

The partial labyrinthectomy approach provides improved access to certain lesions of the medial skull base and requires less brain retraction compared with the retrolabyrinthine approach. It also has the potential to preserve serviceable hearing.

Hand-assisted laparoscopic splenectomy

The success of laparoscopic cholecystectomy has resulted in the broad application of minimally invasive techniques in many surgery specialties. The theoretical advantages of laparoscopy over conventional open operations, including less postoperative pain, faster overall recovery, and better cosmetic results have been achieved leading to its acceptance by surgeons and the public alike. Numerous abdominal procedures have been adapted to minimally invasive approaches including bowel resection, inguinal and ventral hernia repair, anti-reflux techniques, and solid organ removal such as splenectomy.

Experience from a multidisciplinary "dizzy" clinic

OBJECTIVE

To describe the experience of a combined otolaryngology and neurology multidisciplinary clinic in the evaluation, investigation, and management of patients with dizziness.

STUDY DESIGN

Prospective clinical study.

SETTING

Patients were seen in a tertiary referral, multidisciplinary clinic at The Toronto Hospital, University of Toronto, Ontario, Canada.

INTERVENTION

A thorough history, formal otoneurologic examination, and appropriate laboratory investigations were performed. After their assessment, the patient's diagnoses were classified as peripheral, central, psychogenic, or undiagnosed and were then subdivided into specific clinical diagnoses.

RESULTS

The first 812 consecutive patients seen in the multidisciplinary clinic from January 1, 1993 to December 31, 1998 are reported. Five hundred twenty-five (64.7%) patients were found to have a peripheral vestibular cause for their dizziness, 66 (8.1%) had a central cause, 108 (13.3%) had a diagnosis unknown, and 73 (9.0%) were thought to be psychogenic. In 40 (4.9%) patients, a peripheral and central cause were found. More than one type of peripheral disorder was noted in 17.9% of patients with a peripheral vestibular cause for their dizziness, and 12.3% of patients with a central cause for their dizziness had more than one specific type of central nervous system disorder.

CONCLUSIONS

Most patients that were seen in a multidisciplinary clinic had a peripheral vestibular disorder. Central causes of dizziness were relatively uncommon. Serious diseases such as tumor, multiple sclerosis, and encephalitis were rare and unlikely to present with dizziness only. It is important to realize that a patient may have more than one type of disorder accounting for the symptoms, which may represent a spectrum of disease affecting the inner ear.

Nursing assessment of patient readiness for ambulation after cardiac catheterization

Although nurses routinely perform activities that prevent or detect vascular complications following a cardiac catheterization, determining patient readiness for ambulation has received minimal research attention. Educating nurses to determine patient readiness for ambulation is a safe and effective way to promote patient comfort.