Spiral enteroscopy: from “new kid on the block” to established deep small-bowel enteroscopy tool

During the past 10 years small-bowel diagnostics and endoscopic therapy have emerged from the technically rather challenging push-enteroscopy and the occasional perioperative enteroscopy in patients with severe persistent gastrointestinal bleeding, to generally available and advanced deep small-bowel enteroscopy. First, with the introduction of capsule endoscopy in the year 2000, a new era of small-bowel diagnostics was entered [1]. The introduction of capsule endoscopy was quickly followed in 2001 by the launch of the double-balloon enteroscopy (DBE) system [2]. DBE combines excellent small-bowel diagnostic performance and, more importantly and in addition to capsule endoscopy, the possibility to perform diagnostic tissue sampling and therapeutic through-the-endoscope interventions.

Over the past few years, the range of enteroscopic interventions has expanded rapidly: argon plasma coagulation of vascular malformations, clip and injection therapy of active bleeding sites, foreign body (capsule endoscopy) retrieval, dilation of strictures, stent placement, polypectomy, endomucosal resection, endoscopic retrograde cholangiopancreatography procedures in changed anatomy, and percutaneous endoluminal jejunostomy placement. Currently, DBE has a world-wide appreciated place in the diagnostic work-up and therapy in patients with obscure gastrointestinal bleeding. Recent research has shown the additional value of therapeutic interventions in patients with the Peutz-Jeghers syndrome and small-bowel Crohn’s disease.

In 2008, single-balloon enteroscopy (SBE) was introduced as an alternative balloon-assisted enteroscopy system for deep small-bowel exploration [3]. The advantage of this system is its simplified design, making it easier to use and less time-consuming in preparation compared with the DBE system. A theoretical drawback of the SBE system is that due to the different push-and-pull techniques (i. e. angulation of the tip of the endoscope), the grip on the small bowel is not as great as with the DBE technique. This might lead to inferior insertion depths, performance, and in particular complete small-bowel visualization. However, the SBE system has already proven to be capable of providing the same range of therapeutic interventions as DBE. Recent studies comparing both the DBE and SBE techniques showed conflicting results. The first large study from May et al., showed superior performance of DBE compared with SBE for complete small-bowel visualization [4]. However, this study failed to show a significant difference in diagnostic yield. Other studies, although only presented in abstract form so far, showed no significant differences between the two systems, nor in complete small-bowel visualization, nor in diagnostic yield [5] [6].

Spiral enteroscopy is the latest deep small-bowel enteroscopy system to be introduced. The principle of spiral enteroscopy, which was launched in 2008, is amazing in both its design and simplicity: a screw-like tipped overtube in combination with a rotation technique enables the endoscopist, using any type of enteroscope, to perform diagnostic and therapeutic deep small-bowel procedures. The main advantages of the spiral system are that no dedicated enteroscopy system has to be purchased – ‘old-fashioned’ enteroscopes or readily available pediatric colonoscopes can be used in combination with the spiral overtubes to achieve deep small-bowel intubation. Furthermore, the spiral technique is relatively simple and the learning curve seems steep. Except for the introduction of the system into the proximal small bowel, which is as challenging as with the DBE or SBE techniques, further advancement of the spiral system in the small bowel is relatively easy. Another advantage is the stable position inside the small-bowel lumen, with easily stabilized inward and outward movements, making the spiral technique particularly interesting for therapeutic small-bowel interventions. Furthermore, spiral enteroscopy seems to be a fast technique: deep small-bowel intubation is reached within 20 – 30 minutes, reducing the duration of the procedure by almost 50 % compared with DBE or SBE procedures. The first reports of proximal spiral enteroscopy series showed promising depths of insertion, ranging from means of 176 cm to 247 cm, with acceptable diagnostic yields of 27 % – 36 %. Recent clinical trials in tertiary referral centers in Europe and the USA showed similar results in performance parameters. These performances seem to be more or less comparable to the average performances of the DBE and SBE techniques.

Safety issues have been addressed in a large cohort study of 1750 procedures, presented by Akerman et al. at DDW in 2009 [7]. This study showed that major complications were seen in 0.4 % of spiral enteroscopy procedures. A recent US study in elderly patients showed 7 % mild complications and no major complications in a rather large series of 61 patients undergoing spiral enteroscopy procedures. So far, the complication rate of spiral enteroscopy seems to be comparable to the DBE and SBE systems. Surprisingly, in contrast to the DBE system, no cases of acute pancreatitis have been described after spiral enteroscopy.

To date only two studies have performed a head-to-head comparative study between spiral enteroscopy and balloon-assisted enteroscopy. A recent online published study by Khashab et al. compared antegrade spiral enteroscopy with SBE in 92 patients [8]. The mean insertion depth achieved by spiral enteroscopy was significantly deeper compared with SBE, 301 cm and 222 cm, respectively. Other performance parameters were comparable, including total duration of procedure. In this study, the endoscopist had performed 15 – 20 procedures prior to the start of the current study. Unfortunately, this study is of a retrospective design.

The second study, which is by Frieling et al. and is published in this issue of Endoscopy, compared antegrade spiral enteroscopy with DBE in 35 patients in a prospective study [9]. This is the first prospective study comparing spiral enteroscopy with the ‘gold standard’ deep small-bowel enteroscopy system (i. e. the DBE technique). This study showed that both techniques are comparable for performance, including insertion depth, diagnostic yield, and duration. The major limitation of the study was the relatively small number of patients included. Furthermore, the spiral enteroscopy patients were younger, though not significantly so, compared with the DBE group, which might have influenced the overall outcome. From the results of these latter two studies, one might conclude that the performance of spiral enteroscopy is at least comparable to that of SBE and DBE.

In a short period of time, spiral enteroscopy has already proven to be a major player in the field of deep small-bowel endoscopy, and it is an interesting alternative technique to the balloon-assisted enteroscopy systems. The first studies have shown that spiral enteroscopy is safe and effective for deep small-bowel enteroscopy. However, further research is needed to determine the actual value of this technique in patients with suspected small-bowel pathology. The relatively stable position of the spiral overtube, and the easy repositioning of the overtube in the small-bowel lumen, makes the spiral system interesting for therapeutic small-bowel interventions. Hopefully, further technical improvement and refinement of the spiral technique will improve performance in the future. There is a need for clinical studies that focus on therapeutic enteroscopic interventions performed with spiral enteroscopy, to establish the actual clinical impact of this exciting and emerging technique in the field of gastrointestinal endoscopy.

Competing interests: None

References

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