[Atypical lung parenchyma resection with the Hydro-Jet--initial experimental and clinical experiences]

Selective tissue elevation by pressure for endoscopic mucosal resection of colorectal adenoma: first clinical trial

BACKGROUND

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection of large lateral spreading tumors currently are technically limited by complications such as bleeding, perforation, and disturbed large procedural sites, leading to incomplete resection and secondary surgery. Further technical improvements are necessary. The authors previously demonstrated the effectiveness of a focused water jet for elevation of the lamina submucosa in animal studies. For the first time, the clinical application of selective tissue elevation by pressure (STEP) for the treatment of colorectal adenomas as a prospective single-arm human trial is presented.

METHODS

This trial evaluated 59 patients who had primary colorectal adenomas with diameters exceeding 12 mm classified as 0-IIa or 0-IIb according to Paris classification. A submucosal cushion was created with a flexible water jet applicator using the Helix HydroJet. The adenoma was subsequently resected with a mucosal resection snare. All results were recorded. The resected specimens were assessed histologically.

RESULTS

A total of 59 patients underwent resection of 70 lesions with a maximum diameter of 80 mm (mean, 27 mm). Submucosal elevation with the water jet dissector was possible in all cases and locations from the pectinate line to the ileocecal valve. Of the 70 lesions, 64 (91%) were resected completely in one session. Histologically, the resected specimens were found to be adenocarcinomas (n = 2, 3%), adenomas with high-grade intraepithelial neoplasia (n = 24, 34%), adenomas with low-grade intraepithelial neoplasia (n = 38, 54%), and hyperplastic polyps (n = 6, 9%). Hemostasis during the resection was necessary in 24 cases (34%). No perforation required surgical intervention.

CONCLUSION

This first clinical trial to analyze STEP technique demonstrated that STEP used to elevate large mucosal lesions in any location is feasible and facilitates EMR for colorectal adenoma.

First experimental results with a new waterjet dissector: Erbejet 2

BACKGROUND

Waterjet dissection represents a useful technique for many surgical procedures. In this experimental study, the technical features and dissection qualities of the new Erbejet 2 with its new pump and nozzle applicator system are evaluated for its neurosurgical use compared to the established Helix Hydro-Jet.

METHODS

One hundred twenty-six fresh cadaveric pig brains were simultaneously cut with the Helix Hydro-Jet and Erbejet 2. Different pressure levels were applied to cerebral tissue with and without meninges, cerebellum and brainstem. Additionally, dissection characteristics of various cutting media were investigated.

FINDINGS

There was a nearly equal dissection quality at up to 10 bar of both instruments. In contrast to the Helix Hydro-Jet, Erbejet 2 application at higher pressures resulted in an almost linear increase of dissection depth with a small standard deviation. Smoother cutting margins and less foaming were found. Preserved vessels were observed with both devices. Hydroxyaethyl starch led, in contrast to Ringer's solution and isotonic saline solution, to increased dissection width and more foaming.

CONCLUSIONS

The new Erbejet 2 is more precise, with almost linear correlation of pressure and dissection depth compared to the Helix Hydro-Jet. Less foaming and the possible application of various separating media are a considerable advantage. All things considered, the new Erbejet 2 offers more options to enlarge the field of neurosurgical indications for waterjet dissection.

Waterjet dissection of the vestibulocochlear nerve: an experimental study

Object

Waterjet dissection has been shown to protect intracerebral vessels, but no experience exists in applying this modality to the cranial nerves. To evaluate its potential, the authors examined waterjet dissection of the vestibulocochlear nerve in rats.

Methods

Lateral suboccipital craniectomy and microsurgical preparation of the vestibulocochlear nerve were performed in 42 rats. Water pressures of 2–10 bar were applied, and the effect was microscopically evaluated. Auditory brainstem responses (ABRs) were used to define nerve function compared with preoperative values and the healthy contralateral side. The final anatomical preparation documented the morphological and histological effects of waterjet pressure on the nerve.

Results

In using up to 6 bar, the cochlear nerve was preserved in all cases. Eight bar moderately damaged the nerve surface. A 10-bar jet markedly damaged or even completely dissected the nerve. Time course analysis of the ABR demonstrated complete functional nerve preservation up to 6 bar after 6 weeks in all rats. Waterjet dissection with 8 bar was associated with a 60% recovery of ABR. In the 10-bar group, no recovery was seen.

Conclusions

Microsurgical dissection of cranial nerves is possible using waterjet dissection while preserving both morphology and function. The aforementioned jet pressures are known to be effective in neurosurgical treatment of tumors. Thus, waterjet dissection may be useful in skull base surgery including dissection of cranial nerves from tumors. Further studies on this subject are encouraged.

Submucosal cushioning with water jet before endoscopic mucosal resection : Which fluids are effective?

BACKGROUND

Several new techniques have recently been described that allow the endoscopic mucosal resection even of broad-based flat lesions in the gastrointestinal tract. The technique recently described by us of using a water jet dissector (Helix HydroJet) for a selective deposition of liquid in the submucosal lamina has now been combined with different substances, and their effects have been compared.

MATERIAL AND METHODS

Gastroscopies were carried out in 8 pigs under intubation anesthesia, and 2 submucosal cushions each were created in the stomach using one out of 4 test substances (gelatin, glucose 50, hydroxyethyl starch [HES] 10%, dextran 40), as well as one cushion of isotonic saline solution placed in each area via the Helix HydroJet). The height of the submucosal cushions was intermittently measured over a period of 40 or 20 min, respectively, by miniprobe endosonography. In 7 of the animals the stomach was subsequently subjected to mucosal resection. The specimens and the gastric wall were histologically assessed to evaluate the localization of the liquid cushion and the effect on adjacent layers of the gastric wall.

RESULTS

All test substances produced strictly selective liquid cushions in the submucosa. With HES 10% and dextran the maximum height of the cushions initially increased and then decreased during the further course to an average of 90% of the initial height within 40 min. Isotonic saline solution showed the most rapid decrease in height (72% after 20 min). The histological assessment confirmed the selective nature of the liquid deposit in the submucosa.

DISCUSSION

Plasma expanders produced cushions that initially increased in height but then remained constant for a longer period than cushions produced using glucose 50, gelatin, or isotonic saline solution. The combination of transmucosal jet application for elevation of the mucosa with plasma expanders is therefore an interesting approach to optimize endoscopic mucosal resections.

Selective fluid cushion in the submucosal layer by water jet: advantage for endoscopic mucosal resection

BACKGROUND/AIM

Numerous new techniques have recently been reported and described for the endoscopic mucosal resection of large superficial lesions of the gastrointestinal tract. We present here for the first time the application of a water jet dissector for mucosa elevation.

MATERIALS AND METHODS

In an ex vivo study, the effectiveness of a water jet dissector (Helix Hydro-Jet) placed directly on the stomach walls of 8 pigs was examined to create a mucosal elevation. After having determined optimal pressures, angle of application, and application times, 13 submucosal fluid cushions were produced in different areas of the stomach walls of 8 pigs in vivo, and the sizes of the resulting submucosal cushions were measured.

RESULTS

Using pressures between 30 and 70 bar, it was routinely possible to create submucosal fluid cushions in the stomach wall ex vivo as well as in vivo. Histological examination showed a selective edema in the submucosa without damage to the deeper mucosal layers of the gastric wall.

CONCLUSIONS

The capacity of a targeted high-pressure water jet to penetrate the mucosa and selectively create a fluid cushion in the submucosa facilitates endoscopic resection of the mucosa. This new method could contribute to ameliorate the endoscopic treatment of mucosal tumors which previously could not be resected endoscopically due to their size, extent, or location.