Selective muscle botulinum toxin A component paralysis in complex ventral hernia repair.

INTRODUCTION: Repair of complex ventral hernia presents a significant challenge plagued by high morbidity and recurrence. Recent studies have demonstrated significant benefits achievable with preoperative Botulinum Toxin A (BTA) chemical component paralysis to the abdominal wall muscles, facilitating primary closure of complex ventral hernia defects. However, transversus abdominis is known to play an integral role in truncal stability, and its paralysis can result in unwanted physiological changes. This is the first study to report on selective administration of preoperative BTA to internal and external oblique muscles only, thus sparing transversus abdominis from paralysis. METHODS: This is a prospective observational study of 46 patients who underwent either selective two-layer or standard three-layer abdominal wall muscle BTA injection prior to elective laparoscopic ventral hernia repair. Serial abdominal CT imaging was performed to compare defect size and length of the lateral abdominal musculature. RESULTS: 46 patients received preoperative BTA injections (23 in each group). A comparison of gains achieved from chemical component paralysis demonstrated no statistically significant difference between the two groups. Fascial closure was achieved in all cases, with no post-operative sequelae of abdominal hypertension. There are no hernia recurrences to date. CONCLUSION: Preoperative selective muscle chemical component paralysis is an effective technique to counteract the chronic muscle retraction observed in large ventral hernias. Transversus abdominis plays a significant role in truncal and spinal stability, and sparing it from paralysis preserves an important component of abdominal wall physiology and does not detract from the ability to primarily close complex defects.

The macquarie system for comprehensive management of complex ventral hernia.

BACKGROUND: Despite recent advances in the operative management of complex ventral hernia (CVH), significant challenges remain. Closure of large defects can have serious pathophysiological consequences due to chronic contraction and retraction of the lateral abdominal wall muscles. Certain features of CVH make repair technically demanding and time consuming, such as massive fascial defects, unusual hernia locations, involvement of other abdominal wall structures and previous tissue trauma. METHODS: Preoperative assessment with three-dimensional volume rendered CT (3DVR-CT) imaging and an illustrative series of clinical cases is introduced for repair of CVH using laparoscopic approach. RESULTS: CVH presented here include traumatic hernias involving extensive tissue trauma, massive ventral hernias with defects > 20 cm in width, hernias requiring additional procedures such as wiring of ribs, and hernias in difficult locations such as suprapubic and flank hernias. Specific techniques such as individually tailoring mesh and size, transfascial mesh straps fixation and transcutaneous defect closure will be discussed. All hernias in this series have been repaired laparoscopically (Lap) or laparoscopic-open-laparoscopic (LOL) technique with transcutaneous fascial closure. After hernia closure the mesh is placed in either an intra-peritoneal onlay mesh (IPOM) placement or modified Rives-Stoppa technique with pre-peritoneal mesh placement. CONCLUSION: CVH repair requires multidisciplinary planning with management tailored to each patient's clinical and surgical requirements. The surgeon must have a variety of surgical skills and strategies to address the multiple and/or atypical defects that affect these patients.

Laparoscopic repair of complex ventral hernia facilitated by pre-operative chemical component relaxation using Botulinum Toxin A.

PURPOSE: The operative management of complex ventral hernia poses a formidable challenge, despite recent advances in surgical techniques. Recurrence rates after complex ventral hernia repair remain high, and increase with each failed attempt. This study examines the effect of pre-operative abdominal wall chemical component relaxation using Botulinum Toxin A (BTA) to induce temporary flaccid paralysis in order to facilitate laparoscopic repair of large complex ventral hernia. METHODS: This is a prospective evaluation of 27 patients from January 2013 to August 2015 who underwent ultrasound guided BTA injections to the lateral abdominal wall muscles prior to elective complex ventral hernia repair. Non-contrast serial CT imaging was obtained pre- and post-BTA injection to measure change in fascial defect size and abdominal wall muscle thickness and length. Fascial defects were closed and hernias repaired using laparoscopic or laparoscopic-assisted intra-peritoneal onlay mesh (IPOM) techniques. RESULTS: 27 patients received pre-operative BTA injections which were well tolerated with no complications. Comparison of pre-BTA and post-BTA CT imaging demonstrated a significant increase in mean length of the lateral abdominal wall from 15.7 cm pre-BTA to 19.9 cm post-BTA (p < 0.0001), with mean unstretched length gain of 4.2 cm/side (range 0-11.7 cm/side). All hernias were surgically reduced and repaired with mesh, with no early recurrences. CONCLUSION: Pre-operative administration of BTA is a safe and effective technique in the pre-operative preparation of patients undergoing elective complex ventral hernia repair. This technique lengthens and relaxes the laterally retracted abdominal muscles and enables laparoscopic closure of large complex ventral hernia.

FDG-PET nodal staging does not correlate with histopathological nodal stage for oesophageal cancers.

OBJECTIVE: To investigate whether pre-operative N-stage (nodal stage) based on FDG-PET for oesophageal cancers, correlates with final histopathology. Additionally, we assessed if N-stage differs for squamous cell cancers compared with adenocarcinomas and if neoadjuvant therapy alters these results. BACKGROUND: Our current understanding of oesophageal cancer biology means that personalisation of multimodality therapy is based on accurate clinical staging, allied with patient co morbidities and patient preference. METHODS: We conducted a retrospective review of consecutive oesophagectomy cases performed over a ten year period (between 2002 and 2013) from a single tertiary centre. A total of 161 patients were identified in the study period. RESULTS: Overall, 103 specimens with 1402 lymph nodes were included. For both Adenocarcinomas (AC) and Squamous Cell Carcinomas (SCC), there was no significant difference between the N-stage determined by CT vs. FDG-PET (p > 0.05). For AC, there was statistically significant under-reporting of the N-stage by PET compared with the final histopathology (p < 0.01). Subgroup analysis showed that neoadjuvant therapy vs. adjuvant therapy alone did not alter the bias for under-reporting of the N-stage for adenocarcinoma by PET-CT (Bland-Altman bias 0.76 vs. bias 0.75). CONCLUSION: There is little doubt that PET-CT provides useful information in determining metastatic disease however its use in evaluating nodal burden is limited. Theoretically, this should not preclude patients from receiving definitive surgical management but the decision regarding neoadjuvant treatment based on locoregional disease may be affected.

Superior mesenteric artery syndrome: diagnosis and treatment strategies.

INTRODUCTION: Superior mesenteric artery (SMA) syndrome is an unusual cause of vomiting and weight loss resulting from the compression of the third part of the duodenum by the SMA. Various medical and psychiatric conditions may result in the initial rapid weight loss which causes narrowing of the aortomesenteric angle. The vomiting and obstructive syndrome is then self-perpetuated regardless of the initiating factors. The young age and nonspecific symptoms often lead to a delay in diagnosis. DISCUSSION: A series of eight cases is presented reviewing the presentation, investigations, surgical treatment by division of duodenum and duodenojejunostomy, and outcomes. CONCLUSION: SMA syndrome is a well-described entity which must be considered as a cause of vomiting associated with significant weight loss in young adults. Surgical treatment should be allied with psychological assessment to treat any underlying psychosocial abnormality.

Expression of LMO4 and outcome in pancreatic ductal adenocarcinoma.

Identification of a biomarker of prognosis and response to therapy that can be assessed preoperatively would significantly improve overall outcomes for patients with pancreatic cancer. In this study, patients whose tumours exhibited high LMO4 expression had a significant survival advantage following operative resection, whereas the survival of those patients whose tumours had low or no LMO4 expression was not significantly different when resection was compared with operative biopsy alone.

Skills acquired on virtual reality laparoscopic simulators transfer into the operating room in a blinded, randomised, controlled trial.

Virtual reality surgical simulators have proven value in the acquisition and assessment of laparoscopic skills. In this study, we investigated skill transfer from a virtual reality laparoscopic simulator into the operating room, using a blinded, randomised, controlled trial design. Surgical trainees using the LapSim System performed significantly better at their first real-world attempt at a laparoscopic task than their colleagues who had not received similar training, as measured independently by a number of expert surgical observers using four criteria.

Combined forward error control and packetized zerotree wavelet encoding for transmission of images over varying channels.

One method of transmitting wavelet based zerotree encoded images over noisy channels is to add channel coding without altering the source coder. A second method is to reorder the embedded zerotree bitstream into packets containing a small set of wavelet coefficient trees. We consider a hybrid mixture of these two approaches and demonstrate situations in which the hybrid image coder can outperform either of the two building block methods, namely on channels that can suffer packet losses as well as statistically varying bit errors.

Covariability of V3 loop amino acids.

We reanalyzed for covariability a set of 308 human immunodeficiency virus type 1 (HIV-1) V3 loop amino acid sequences from the B envelope sequence subtype previously analyzed by Korber et al.,1 as well as a new set of 440 sequences that also included substantial numbers of sequences from subtypes A, D, and E. We used the measure employed by Korber et al., essentially the likelihood ratio statistic for independence, plus two additional measures as well as clade information to examine the new set and both data sets simultaneously. We set forth the following conclusions and observations. The eight most highly connected sites identified through these statistical approaches included all of the six residues previously shown to have determining roles in structure, immunologic recognition, virus phenotype, and host range; each of the seven pairs of covariant sites found by Korber were signaled by our additional two measures in the set of 308 sequences, although 2 or 3 dropped out of the examination of the set of 440 when the requirement of stringent significance was applied for some or all of the three tests, respectively; using the same criteria, a total of 20 (including 5 Korber et al. pairs) or a total of 6 (including 4 Korber et al. pairs) were found when the set of 440 was added. Several limitations to statistical analysis of this type of HIV sequence data were also noted. For example, the data sets were, by historical necessity, collected haphazardly. For example, it was not possible to separate substantially sized groups out according to time of or since infection, disease status, antiviral treatment, geography, etc. There was also an enormous "wealth of significance" within the data. For example, for one measure the 440 data set showed 233 of the 465 pairs of sites with a likelihood ratio statistic of < 0.001. Last, most sites had consensus amino acids in 80% or more of the sequences; hence, there was an absence of data on many combinations of amino acids. Given the observed linkage between sites shown to be covariable and those known to have critical biological function, the statistical approaches we and Korber et al. have outlined may find use in predicting critical structural features of HIV proteins as targets for therapeutic intervention.

Vector quantization of image subbands: a survey.

Subband and wavelet decompositions are powerful tools in image coding because of their decorrelating effects on image pixels, the concentration of energy in a few coefficients, their multirate/multiresolution framework, and their frequency splitting, which allows for efficient coding matched to the statistics of each frequency band and to the characteristics of the human visual system. Vector quantization (VQ) provides a means of converting the decomposed signal into bits in a manner that takes advantage of remaining inter and intraband correlation as well as of the more flexible partitions of higher dimensional vector spaces. Since 1988, a growing body of research has examined the use of VQ for subband/wavelet transform coefficients. We present a survey of these methods.

Thoracic CT images: effect of lossy image compression on diagnostic accuracy.

PURPOSE: To evaluate the effects of lossy image (noninvertible) compression on diagnostic accuracy of thoracic computed tomographic images. MATERIALS AND METHODS: Sixty images from patients with mediastinal adenopathy and pulmonary nodules were compressed to six different levels with tree-structured vector quantization. Three radiologists then used the original and compressed images for diagnosis. Unlike many previous receiver operating characteristic-based studies that used confidence rankings and binary detection tasks, this study examined the sensitivity and predictive value positive scores from nonbinary detection tasks. RESULTS: At the 5% significance level, there was no statistically significant difference in diagnostic accuracy of image assessment at compression rates of up to 9:1. CONCLUSION: The techniques presented for evaluation of image quality do not depend on the specific compression algorithm and provide a useful approach to evaluation of the benefits of any lossy image processing technique.

Tree-structured vector quantization of CT chest scans: image quality and diagnostic accuracy.

The authors apply a lossy compression algorithm to medical images, and quantify the quality of the images by the diagnostic performance of radiologists, as well as by traditional signal-to-noise ratios and subjective ratings. The authors' study is unlike previous studies of the effects of lossy compression in that they consider nonbinary detection tasks, simulate actual diagnostic practice instead of using paired tests or confidence rankings, use statistical methods that are more appropriate for nonbinary clinical data than are the popular receiver operating characteristic curves, and use low-complexity predictive tree-structured vector quantization for compression rather than DCT-based transform codes combined with entropy coding. The authors' diagnostic tasks are the identification of nodules (tumors) in the lungs and lymphadenopathy in the mediastinum from computerized tomography (CT) chest scans. Radiologists read both uncompressed and lossy compressed versions of images. For the image modality, compression algorithm, and diagnostic tasks the authors consider, the original 12 bit per pixel (bpp) CT image can be compressed to between 1 bpp and 2 bpp with no significant changes in diagnostic accuracy. The techniques presented here for evaluating image quality do not depend on the specific compression algorithm and are useful new methods for evaluating the benefits of any lossy image processing technique.