Transanal total mesorectal excision for rectal cancer: early outcomes in 50 consecutive patients.

AIM: Minimally invasive approaches to proctectomy for rectal cancer have not been widely adopted due to inherent technical challenges. A modification of traditional transabdominal mobilization, termed transanal total mesorectal excision (TaTME), has the potential to improve access to the distal rectum. The aim of the current study is to assess outcomes following TaTME for rectal cancer. METHOD: This is a retrospective analysis of a prospectively maintained database of consecutive patients who underwent TaTME for rectal cancer at a single institution. The study period was from 1 March 2012 to 31 July 2015. RESULTS: During the study period 50 patients underwent TaTME. The median tumour distance from the anal verge was 4.4 (3.0-5.5) cm. The rate of conversion from a planned minimally invasive approach was 2.2%. The median operative time was 267.0 (227.0-331.0) min. The median lymph node yield was 18.0 (12.0-23.8), the macroscopic quality assessment of the resected specimen was incomplete in 2% and the circumferential resection margin positivity rate was 4%. Intra-operative morbidity occurred in 6% and the 30 day morbidity rate was 36%. The median length of stay was 4.5 (4.0-8.0) days. The median follow-up was 15.1 (7.0-23.2) months; two patients have developed a local recurrence and eight patients have developed distant recurrence. CONCLUSION: These data suggest that TaTME for rectal cancer is feasible with an acceptable pathological outcome and morbidity profile. Further data on functional and long-term survival outcomes are required.

Robotic transanal surgery for local excision of rectal neoplasia, transanal total mesorectal excision, and repair of complex fistulae: clinical experience with the first 18 cases at a single institution.

BACKGROUND: Robotic transanal surgery represents a natural evolution of transanal minimally invasive surgery. This new approach to rectal surgery provides the ability to perform local excision of rectal neoplasia with precision. Robotic transanal surgery can also be used to perform more advanced procedures including repair of complex fistulae and transanal total mesorectal excision. METHODS: Data from patients who underwent transanal robotic surgery over a 33-month period were retrospectively reviewed. Patients underwent three types of procedures using this approach: (a) local excision of rectal neoplasia, (b) transanal total mesorectal excision, and (c) closure of complex fistulae, such as rectourethral fistulae. RESULTS: Eighteen patients underwent robotic transanal surgery during the 33-month study period. Of these, nine patients underwent local excision of rectal neoplasia; four patients underwent transanal total mesorectal excision; four patients underwent repair of rectourethral fistulae; and one patient underwent repair of an anastomotic fistula. Of the patients undergoing robotic transanal surgery for local excision, 6/9 were resections of benign neoplasia, while 3/9 were resections for invasive adenocarcinoma. There was no fragmentation (0/9) noted on any of the locally excised specimens, while one patient (1/9) had a positive lateral margin. During the mean follow-up of 11.4 months, no recurrence was detected. Four patients underwent robotic-assisted transanal total mesorectal excision for curative intent resection of rectal cancer confined to the distal rectum. Mesorectal quality was graded as complete or near complete, and an R0 resection was performed in all four cases. Other transanal robotic procedures performed were the repair of rectourethral fistulae (n = 3) and anastomotic fistula (n = 1). This approach was met with limited success, and only half of the rectourethral fistulae were closed. CONCLUSIONS: Robotic transanal surgery for local excision, transanal total mesorectal excision, and repair of fistulae is feasible, although these new approaches represent a work-in-progress. Improvement in platform design will likely facilitate the ability to perform more complex procedures. Further research with robotic transanal approaches is necessary to determine whether or not this approach can provide patients with significant benefit.

Transanal minimally invasive surgery for total mesorectal excision (TAMIS-TME): results and experience with the first 20 patients undergoing curative-intent rectal cancer surgery at a single institution.

BACKGROUND: Transanal TME is a new approach to performing minimally invasive rectal resection. It is particularly well suited for patients with locally advanced distal rectal cancer and obesity, where the abdominal approach is challenging. Transanal TME can be performed with either TAMIS or TEM. Here, we report our initial experience with transanal TME using TAMIS (TAMIS-TME). METHODS: Patients were selected to undergo transanal TME using the TAMIS platform (TAMIS-TME) primarily for malignant disease, but also for select cases of benign disease. Transanal TME defines a "bottom-up" approach to en bloc rectal cancer resection. Transanal TME requires abdominal access for proximal colonic mobilization and is often done in conjunction with a laparoscopic approach. RESULTS: During a 32-month period, 20 patients underwent TAMIS-TME with curative intent. The primary indication for transanal TME was distal, locally advanced rectal cancer. The median age of rectal cancer patients at the time of surgery was 57 years (range 36-73 years) with 30% (6) female and 70% (14) male. The median body mass index (BMI) measured was 24 kg/m(2) (range 18-41 kg/m(2)); this included six patients (30%) with obesity (BMI ≥ 30 kg/m(2)). Mean operating time was 243 min (range 140-495 min) with blood loss averaging 153 ml. Postoperative length of stay averaged 4.5 days (range 3-24 days). There was no 30-day postoperative mortality. Surgical complications included wound infection (n = 2), pelvic abscess (n = 4), and prolonged ileus (n = 4). The anastomotic leak rate was 6.7% (1/15). Of the 20 patients who underwent resection, 90% (18/20) had negative margins. Pathologic grading of the TME specimen revealed that 85% (17/20) of transanal TME specimens were found to have "completely" or "near-completely" intact mesorectal envelopes. Data collected during the 6-month median follow-up period revealed that only one patient had developed distant metastasis. There was no locoregional recurrence in any of the patients. CONCLUSIONS: Transanal TME is a feasible method for oncologic resection of locally advanced mid- and distal-rectal cancer with curative intent. It has special application for patients with obesity and anatomic constraints such as a narrow male pelvis.

Robotic-assisted transanal surgery for total mesorectal excision (RATS-TME): a description of a novel surgical approach with video demonstration.

A new era has emerged in rectal cancer surgery--transanal total mesorectal excision (TME). Various platforms have been used to facilitate this novel approach, including transanal minimally invasive surgery (TAMIS) and transanal endoscopic microsurgery. We have previously reported the use of TAMIS-TME. This is a report of the first human case of robotic-assisted transanal surgery for TME.

Transanal minimally invasive surgery for total mesorectal excision (TAMIS-TME): a stepwise description of the surgical technique with video demonstration.

Transanal minimally invasive surgery (TAMIS), which can provide high-quality local excision for rectal neoplasia, has emerged as an important alternative to transanal endoscopic microsurgery. The role of TAMIS beyond local excision has also been explored, and it has been shown that this platform can be used for complete rectal resection with total mesorectal excision (TME). The stepwise approach to TAMIS for TME is described and illustrated in video format.

Reentrant circuits and the effects of heptanol in a rabbit model of infarction with a uniform anisotropic epicardial border zone.

INTRODUCTION: The purpose was to study reentry in a rabbit model of infarction. METHODS AND RESULTS: A model of an infarct epicardial border zone was produced in Langendorff perfused rabbit hearts by freezing the inner two thirds of the left ventricular wall, allowing only a thin epicardial muscle layer to survive. Reentrant circuits causing stable ventricular tachycardia occurred in the surviving rim of epicardial muscle as shown by mapping impulse propagation with a 196-electrode array. The circuits were functional, and reentry did not occur around an anatomical obstacle. Slow conduction in the circuits was caused by the anisotropic properties of the epicardial muscle. Activation in the circuits was slow transverse to the long axis of the fiber bundles and rapid parallel to the long axis. Other features of the circuits, including orientation of the central functional line of block parallel to the fiber long axis, and an oval shape are also characteristic of anisotropic reentry. Since the slow conduction causing reentry is a result of poor transverse intercellular coupling, we determined whether the "uncoupler" heptanol would cause block in the circuits and terminate tachycardia. Heptanol in concentrations up to 1.2 mM slowed conduction in the transverse and longitudinal directions in the circuits and sometimes extended the central line of functional block. It did not, however, stop reentry because the reentrant impulse was still able to conduct around the ends of the block line. CONCLUSION: Drugs that decrease intercellular coupling may not be effective antiarrhythmic agents when uniform anisotropy causes functional reentry.

[Intracellular microelectrode study of the electrophysiological effects of contrast media]. / Etude par microélectrodes intracellulaires des effets électrophysiologiques des produits de contraste.

Intracellular microelectrodes were used to study the electrophysiological effects on action and resting potentials, refractory periods and conduction velocities of four contrast media administered either as 1/100 and 1/1000 solutions or as 20 mg bolus injections. The products studied were Telebrix, which has high osmolality (2100 mOsm/kg) and three other contrast media with lower osmolatity (700 mOsm/kg), including Hexabrix, which contains sodium, and Iopamidol and Iohexol which are sodium-free. The parameters measured were not modified by Hexabrix and Telebrix, whereas Omnipaque and Iopamiron induced varied and significant changes in these parameters, notably in concentrations of 1/100 and as bolus injections. It is suggested that the latter contrast media should be used in non-cardiovascular explorations and in patients without confirmed heart disease.

[Cellular electrophysiological and histopathological study of the effects of continuous electric current on the sheep heart]. / Etude électrophysiologique cellulaire et histopathologique des effets du courant électrique continu sur le coeur de mouton.

The energy released in electrode catheter ablation is spent on thermal, mechanical and electrical effects. The relative importance of these effects and their role in the adverse reactions of the method are controversial. Low-energy shocks have been shown to modify cellular electrophysiological and histopathological parameters in the sheep heart. The purpose of this study was to individualized the effects of the electric current itself, using an isolated electrode to suppress barotrauma and reduce the amount of energy delivered. Three fragments of epicardium, seven false tendons and eight loop-shaped strips were placed in an electrophysiology bath perfused with Tyrode's solution and subjected to an electric field induced by an 18 V battery without discharge from a condenser, so that all mechanical effects were suppressed. The electric field was supplied via an isolated electrode, thus preventing the current from leaking through the Tyrode's solution and forcing it across the fragments studied. The electrophysiological parameters were studied by the microelectrode method on both sides of the area subjected to the electric field. This was followed by a histological study. The current intensity was 15 mAmp, and the energy delivered in one second was 270 mJ. Membrane depolarization was constant, and no automatic of post-depolarization activity was observed after the electric current was applied. The two-dimensional conduction accounted for the absence of block in the epicardial fragments. In the false tendons a conduction block constantly appeared between the two electrodes, associated with a decrease in conduction velocity in the recovery phase (2.1 +/- 0.24 vs 1.8 +/- 0.23 m/s, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

[Morphologic study of cardiac cells in sheep before and after electric shock]. / Etude morphologique des cellules cardiaques de mouton avant et après choc électrique.

A combined electrophysiological and histopathological study was conducted on sheep myocardium fragments rich in easily identifiable conduction cells subjected to electric shocks of varying intensity. Tissue fragments were immersed in a thermostatically-controlled bath at 37 degrees C, perfused with a carbonated standard tyrode solution at the rate of 30 ml/min and stimulated at a constant bipolar 1 C/sec tension twice as high as the threshold of diastolic excitability. After measurement of reference values, electric shocks of 2 to 80 joules were delivered between two electrodes placed on both sides of the tissue fragment. The electrophysiological part of the study showed disorders of conduction which, depending on the energy delivered, were more or less complete and reversible. The histopathological part of the study showed that conduction tissue was extremely fragile, even to low-energy shocks. This fragility was in glaring contrast with the relatively modest damage suffered by myocytes. Liquefaction and/or coagulation of Purkinje's cells was also striking, as it extended over an area much wider than that subjected to the shock. Thus, with medium intensity shocks destroyed conduction bundles were seen to creep between myocytes that often were perfectly normal or showed rare hypercontraction bands. Some myocytes were in the process of degeneration or even eosinophilic necrosis, but except in case of violent shock these were more or less isolated elements in the vicinity of the stimulated area. The fragility of conduction tissue and its selective damage by low-intensity shocks may be explained partly by its low impedance which allows preferential passage of the electric current.(ABSTRACT TRUNCATED AT 250 WORDS)

[Cellular electrophysiological effects of fulguration by low energy shock]. / Effets électrophysiologiques cellulaires de la fulguration par des chocs de faible énergie.

In spite of the increasing use of catheter ablation in the treatment of refractory ventricular and supraventricular arrhythmias, little information is available on the basic electrophysiological effects of the treatment. Although high-energy shocks are still usually delivered, the current trend is toward lower energies. We studied the electrophysiological effects of non-deflagrating anodic shocks of 2 joules on preparations of sheep ventricular myocardium and Purkinje's fibers. The shocks were delivered by a standard defibrillator between a small-area catheter electrode and a wide-area inert electrode. Action potentials were recorded by the standard microelectrode technique. After the shocks were delivered, the Purkinje's cells that were 5 mm distant from the shocked area on either side were depolarized in the -30 to -40 mV zone, but they progressively reverted to an almost normal resting potential. Recovery was bi-exponential, with time constants of about 1 min and 10 min respectively. Similarly, the conduction block induced by the electric shock in 100% of the cases was reversible in 50%. It must be noted that at the time of conduction recovery the pattern observed was that of electrotonic conduction where the distal action potential conducted was preceded by a pre-potential. This pattern always regressed progressively, with gradual disappearance of the pre-potential in the distal cells, suggesting that the unexcitable area had vanished or become smaller. Although a normal 1/1 conduction and normal action potentials returned in the cells that were 5 mm distant from the shocked area, recordings performed at a distance of 1 to 4 mm from that area disclosed alterations of action potentials that were usually irreversible.(ABSTRACT TRUNCATED AT 250 WORDS)

Electrophysiological effects of contrast media.

The effect of two low osmolar contrast media (sodium ioxitalamate and sodium ioxaglate) and two nonionic media (iohexol and iopamidol) on cellular electrophysiological properties of sheep myocardium and Purkinje fibres was studied at two concentrations of each medium. Neither sodium ioxitalamate nor ioxaglate had significant effects on any of the parameters measured. Iohexol (10 mL/L) caused a loss of resting potential, a decrease in action potential and duration, and a decrease in refractory period of the myocardium. No change in Purkinje fibres was observed. Iopamidol induced an increase in relative refractory period in both myocardium and Purkinje fibres at 1 mL/L and had a significant effect on all parameters studied at 10 mL/L. Automaticity was not observed after perfusion with any agent at either concentration.

[Cellular effects of electric shock. Definitions, physical principles, cellular electrophysiology and morphological analysis of the shocked areas]. / Effets cellulaires des chocs électriques. Définitions, principes physiques, électrophysiologie cellulaire et analyse morphologique des zones choquées.

In this experimental study the electrophysiological changes induced by electric discharges such as used clinically in some arrhythmias refractory to the usual treatments were investigated. With energies comprised between 2 and 80 joules profound modifications of the electrophysiological properties of muscle cells and conduction were observed. These modifications included loss of resting potential, inactivation of the fast sodium flux, increase in refractory periods of conduction and disorders of conduction through the shocked areas with, at most, complete block sometimes reversible when low-energy currents were used. With the same amounts of energy these effects were maximal when the current traversed tissues positioned between the electrodes and decreased in all other cases. Usually, with currents of 10 joules or more all electric activity ceased in a radius of about one centimetre around the shocked area.

A study of electrical activation of the heart by laser spectrometry. An optical study of cellular action potentials.

The action potentials of working myocardium and conduction tissues, traditionally recorded by intracellular glass microelectrodes, may also be studied at a distance without physical contact using an optical system. The tissues have to be stained with a dye which fluoresces when illuminated by a laser beam, and the spectrum of the fluorescence must be sensitive to variations of the transmembrane action potential. The responses obtained by the microelectrode and the optical systems were tested on several different preparations (sheep and mouse myocardium). Three types of signals were obtained: asynchronous, synchronous and mixed, related to myocardial contraction, the action potential and the excitation-contraction couple, respectively. The use of continuous and pulsed mode laser measurements by optoelectronic methods (photomultiplier, monochromator), and imaging of the electrical activation by a CCD video camera may lead to the development of high definition mapping of myocardial activation which would be used for studying arrhythmias in experimental and even clinical models.

[A new technic for recording cardiac action potentials. Laser spectrometry]. / Une nouvelle technique d'enregistrement des potentiels d'action cardiaques. La spectrométrie laser.

The new technique described rests on analysis of the fluorescence emitted by a potential-sensitive dye after excitation by a laser light of suitable wavelength. This technique, which requires no physical contact with tissues, should also be applied to the study of surface activation, using more potent pulsed laser rays and video methods.

[Electric activation of the heart using laser spectrometry. 1. Study of transmembrane action potentials using optical technics]. / Etude de l'activation électrique cardiaque par spectrométrie laser. Première partie. Etude par moyens optiques du potentiel d'action transmembranaire.

The action potentials of the contractile myocardium and conduction cells are usually recorded by intracellular glass microelectrodes but they call also be obtained at a distance and without physical contact by optical techniques. The myocardial fragment must be stained with a dye which, when illuminated by a laser beam, emits a fluorescence whose wave length is related to the transmembrane potential. The responses obtained were checked by microelectrode and optical techniques on several types of preparation (sheep myocardium, sheep Purkinje cells, mouse myocardium). The morphology of the action potential was identical by both methods; the beginning of phase 0 in particular was identical with both methods, eliminating any mechanical activity. Contraction appeared later, during the plateau phase of the action potential with a measurable interval corresponding to the excitation- contraction coupling time. Remote recordings of action potentials without physical contact with the preparation, should enable very accurate myocardium activation mapping using CCD video techniques.