Transanal endoscopic microsurgery in 143 consecutive patients with rectal adenocarcinoma: results from a Danish multicenter study

OBJECTIVE

The long-term results are presented on total survival, cancer-specific survival and recurrence in 143 consecutive patients treated with transanal endoscopic microsurgery (TEM) for adenocarcinoma of the rectum.

METHOD

Four Danish centres established in 1995 a database for registration of all TEM procedures. Data were supplemented from pathology reports and death certificates were checked in the Danish patient registry. Data were analysed with multivariance regression and survival analysis.

RESULTS

The T stage was as follows: T1 50%, T2 33%, T3 14%, and stage unknown 3%. TEM was performed with curative intent in 43%, for compromise in 52% and for palliation in 5%. Five-year total survival was 66% and 5-year cancer-specific survival 87%. Cancer-specific survival for T1 was 94%. The significant predictors for total survival were age and tumour size. For cancer-specific survival T stage, radical resection, tumour size and recurrence were significant predictors. Eighteen per cent had recurrence and 15% had immediate reoperation.

CONCLUSION

The TEM provides good long-term results for pT1 cancers. In old patients and patients with co-morbidity TEM may provide acceptable long-term results for T2 cancers. Tumours larger than 3 cm should not be treated with TEM for cure.

Rectal adenocarcinoma and transanal endoscopic microsurgery. Diagnostic challenges, indications and short term results in 142 consecutive patients

PURPOSE

The objective of this study was to present short-term results of transanal endoscopic microsurgery (TEM) of rectal adenocarcinomas registered in a national database.

METHODS

A Danish TEM group was established in 1995. The group organized a database for prospective and consecutive registration of all TEM procedures. The perioperative course of all rectal cancers treated with TEM and registered in this database is analysed.

RESULTS

One hundred forty-two patients had TEM for rectal cancer. In 43%of the patients, the cancer diagnosis was not recognized before TEM. Eighty-five percent of all tumors were classified as benign based on macroscopic appearance; on digital rectal examination, 35% were benign, rectal ultrasound classified 15% as benign, and the preoperative biopsy was benign in 36%. Forty-three cancers (29%) were classified as low risk cancers. High ages were an indication for TEM in 22% and concurrent disease in 21%. Minor complications were encountered in 39 cases, major complications in 4 cases, and 1 patient died within 30 days.

CONCLUSION

All larger rectal tumors should be evaluated for malignancy before treatment, even if TEM is the only surgical option, due to high age and comorbidiy. Rectal ultrasound appears to produce the fewest false negative results, but it should be combined with biopsies and clinical evaluation. Multiple biopsies may be beneficial in the case of larger adenomas. When resecting large sessile tumors, there is a considerable risk of incomplete radicality. The short term mortality and morbidity of TEM is low even in old patients with comorbidiy.

Rabbit sphincter of Oddi and duodenal pressure and slow-wave activity. Effects of cholecystokinin

BACKGROUND

The presence of sphincter of Oddi (SO) slow waves has been noted in earlier studies on the effect of cholecystokinin (CCK) on the SO, but a more thorough description of changes in SO slow-wave and pressure activity induced by CCK is needed.

METHODS

The SO and duodenum in anaesthetized rabbits were prepared with perfused catheters and bipolar electrodes. Increasing, successive doses of CCK (1/32 to 1/1 Ivy Dog Units (IDU)/kg) were administered intravenously every 15th min. The digitized recordings were scored on a computer in control and stimulatory CCK sequences.

RESULTS

CCK had a significantly stimulatory effect on SO and duodenum when estimated as area below pressure peaks (p < 0.001), but quantitatively, this effect did not differ in the two organs (p = 0.59). CCK significantly decreased SO slow-wave frequency (p < 0.05), whereas a similar trend in duodenal slow-wave frequency failed to reach statistical significance. Most pressure peaks recorded from the SO were associated with only one slow wave ('simple peak'), but the incidence of broad, irregular peaks belonging to more than one slow wave ('complex peaks') was significantly higher in CCK sequences (p < 0.02). Spectral analysis of SO pressure and slow-wave activity confirmed the dominating one-to-one relation between SO slow-wave and pressure peaks up to 1/4 IDU/kg, but also showed the disturbance caused by the increasing number of complex peaks generated by doses of at least 1/2 IDU/kg.

CONCLUSIONS

CCK increases SO and duodenal activity equally. Up to a CCK dose of 1/4 IDU/kg the SO slow-wave regulatory mechanism is undisturbed, but higher doses lead to a fall in slow-wave frequency and qualitative changes in the relation between SO pressure and slow-wave activity.

Effects of transmural field stimulation in isolated muscle strips from rabbit sphincter of Oddi and duodenum

The purpose of the study was to compare the effect of transmural field stimulation (TMS) on isolated smooth muscle strips from rabbit sphincter of Oddi (SO), duodenal circular layer (Dc) and duodenal longitudinal layer (D1). The strips were suspended in thermostatically controlled 5-ml organ baths containing Krebs solution constantly bubbled with 5% CO2 in O2. TMS was delivered through platinum electrodes (140 V, 0.4 ms, 5 s trains, 40 Hz). The TMS responses could be divided in two main responses: (1) contraction initiated after cessation of the stimulus train, preceded by an inhibitory phase during TMS ('off'); and (2) contraction initiated during TMS ('duration'). The 'duration' response was observed in one out of 20 strips in the SO and Dc compartments, whereas 11 D1 strips (55%) showed 'duration' responses (P < 0.001). Atropine (10(-6)) converted all 'duration' responses to an 'off' response preceded by an inhibitory phase during TMS and reduced the contractile amplitudes with 40-65%. L-NNA significantly increased the number of 'duration' responses in all types of muscle, and caused a 40% increase in D1 contractile amplitude. Inhibitory responses could not be removed by atropine, propranolol and phentolamine. The results suggest that the intrinsic innervation of SO and duodenal muscle consists of a mixture of excitatory, cholinergic and inhibitory NANC pathways. The latter may utilize, wholly or partly, NO or a related compound as transmitter. A relative dominance of excitatory, cholinergic responses was present in the D1 strips, whereas inhibitory responses were dominating in the SO and Dc strips.

The duodenojejunal junction and Treitz ligament in the regulation of duodenal emptying

In chronic experiments in dogs the evacuatory and absorptive duodenal functions and the level of duodenogastric reflux (DGR) in sham-operated dogs and dogs with transected Treitz ligament (TL) and resected duodenojejunal junction (DJJ) were studied. The electrophysiologic characteristics of the antrum, duodenum, and DJJ in sham-operated dogs were examined. It was shown that there is a coordination of gastric and duodenal solid carbohydrate food emptying. The process of evacuation from both organs was characterized by three closely correlated phases, phase 2 of emptying being exponential. In the TL transection and DJJ resection groups the coordination of gastric and duodenal emptying disappeared. The rate of carbohydrate solid food evacuation from the duodenum decreased, on average, by 45.5% +/- 5.5% (P < 0.05); phase 2 of duodenal emptying became unexponential, and the level of DGR considerably increased. The rate of duodenal absorption of main organic chyme components increased significantly in most of the time intervals studied. Significantly higher amplitudes of slow waves and spike potentials were recorded from the DJJ than from the duodenum. We conclude that the DJJ and TL are possible regulators of duodenal emptying. The DJJ is probably a functional sphincter that provides coordinated activity of the stomach and duodenum.

Mechanical properties of isolated smooth muscle from rabbit sphincter of Oddi and duodenum

Isolated smooth muscle from rabbit sphincter of Oddi (SO) and duodenum were mounted in organ baths. The SO strips were obtained as transversal strips from the midsection of the SO. The duodenal strips were prepared as longitudinal (Dl) or circumferential (Dc) strips. Resting length was defined. Carbachol was used for activation of the contractile apparatus. By repeatedly increasing the length of the strips by 20% of the resting length and recording values of resting and active tension, length-tension relations for each muscle type were constructed. None of the strips developed active resting tension. Twelve of the Dl strips (75%) developed spontaneous contractions versus four of the Dc strips (10%) and one of the SO strips. The strips eventually reached a length (Lo) at which further elongation gave no additional increase in active tension development. The Lo from the Dc strips differed significantly from SO Lo (p greater than 0.02) and Dl Lo (p less than 0.02), indicating structural differences. SO Lo and Dl Lo did not differ significantly. Differential extension of these tissues should be applied in future experiments on smooth muscles from this area.

Rabbit sphincter of Oddi has a certain autonomy: characteristic features

Simultaneous recordings of electromyography and manometry were obtained from rabbit sphincter of Oddi (SO) and duodenum. Three different patterns of activity were observed in SO and in duodenum: 1) a low-amplitude (less than 3 cm H2O) pattern of background oscillations with 2) superimposed high-amplitude (4-20 cm H2O) contractions and 3) occasional complex contractions consisting of an elevation of the basal pressure with superimposed smaller contractions. A certain SO autonomy was evident: 57.6% of SO pressure peaks could not be assigned to any duodenal activity. The distribution of SO pressure peak amplitudes could not be described by a simple normal distribution. The distribution of SO pressure peak amplitudes with concomitant duodenal activity differed from the overall distribution (p less than 0.001). Whereas a substantial part of SO pressure peaks greater than 4 cm H2O had no or low-amplitude corresponding duodenal pressure activity, duodenal pressure peaks greater than 4 cm H2O almost invariably were associated with SO pressure peaks. It is concluded that rabbit SO does possess a certain autonomy, but at the same time a close functional connection exists between the two compartments.

Rabbit sphincter of Oddi and duodenum are regulated by slow waves with a common basic-mode activity

Simultaneous recordings of pressure and slow-wave activity were obtained from the sphincter of Oddi (SO) and the duodenum in anesthetized rabbits. Histographic analysis of the recordings was performed when the following criteria were fulfilled: 1) slow waves must be present in the EMG recordings from both compartments; and 2) only pressure recordings with sufficient pressure activity (greater than 50 peaks in 10 min) would be considered. Of 12 animals fulfilling the criteria for histographic analysis of 4 channels, a common basic-mode activity was found in all channels in 9 animals (75%). Of three animals fulfilling the criteria for histographic analysis of three channels, a common basic-mode activity was seen in all channels in all animals (100%). A correlation between the amplitude of the slow waves and the amplitude of the elicited pressure peaks in the SO was significant at a 5% level or better in 12 animals (80%). In some of the animals episodes of low-amplitude pressure activity was observed in the SO, occurring synchronously with slow waves devoid of spike activity. It is concluded that rabbit SO and duodenum are paced by slow waves with a common basic-mode activity in most animals. Slow waves may not only be the chief determinant of the contractile rhythm but may also have a certain influence on the force of the individual SO contractions. It is suggested that slow waves per se may be able to mediate contractile activity.

[Oddi's sphincter dysfunction]

Dysfunction of the sphincter of Oddi (SOD) is an uncommon condition which must be considered in cases of persistent pain in the upper abdomen following uncomplicated cholecystectomy, when disease in other organs, such as gastric ulcer, esophagitis and pancreatitis has been eliminated. The pathogenesis is not fully elucidated, but it is assumed that the cholecystectomy in some cases induces an increased tendency to spasm in the sphincter of Oddi (SO), and, perhaps in connection with an increased sensitivity to pressure elevations in the biliary tree, results in attacks of pain. Whether fibrosis (stenosis) of the SO due to instrumentation or passage of stones is part of the etiology is obscure. Endoscopic retrograde cholangiopancreaticography with papillary manometry should be performed in all cases where SOD is suspected. An elevated basal pressure in SO seems to be the best indicator of SOD. In cases unresponsive to conservative treatment, endoscopic sphincterotomy may be considered. This treatment is not finally evaluated, but apparently the effect is good, especially in patients with elevated basal pressure in SO. It is emphasized that the knowledge of the behavior and regulation of SO is incomplete and that this should be remembered when criteria for SOD are applied.

A model for simultaneous study of pressure and electric events in the rabbit sphincter of Oddi and duodenum

An animal experimental model featuring simultaneous recordings of electromyography and pressure from the sphincter of Oddi (SO) and duodenum is demonstrated. On the basis of data from 10 rabbits, pressure recordings from the SO were shown to have phasic activity with an average basic pressure peak interval of 2.6 to 3.5 sec. Histographic analysis of SO pressure recordings showed a multimodal appearance, suggesting that the activity is paced. A substantial amount of overlap between SO and duodenal contractions was observed. As many as 30% of the pressure peaks recorded from the SO could not be assigned to a spike complex in the corresponding EMG tracings. It is suggested that combined recordings of EMG and pressure activity are needed to characterize fully the motility of the SO and duodenum.