Our experience of the novel “flexible stylet method” for insertion of PD catheter in eight high-risk patients

Background

Perforation of intra-abdominal organs such as the bowel and urinary bladder is one of the most serious complications related to peritoneal dialysis catheter (PDC) insertion procedures. Such a risk increases in patients with a history of prior abdominal surgery or irradiation. The “alpha-replacer” is a unique wire that is usually soft, but becomes harder if coiled in the hand. Application of this equipment as a stylet might improve the safety and effectiveness of PDC insertion.

Case presentation

A total of eight high-risk patients (organic adhesion, bleeding tendency, poor cardiac function, or malnutrition, or some of these) underwent a new peritoneal dialysis catheter (PDC) insertion procedure named “flexible stylet method” using alpha-replacer as a stylet. As a consequence, the maneuver was completed successfully in all patients and neither patient developed any major complications.

Conclusions

The novel “flexible stylet method” as described herein offers effective and safe treatment.

Perforation of intra-abdominal organs such as the bowel and urinary bladder is one of the most serious complications related to the peritoneal dialysis catheter (PDC) insertion procedure [1]. Such a risk increases in patients with a history of prior abdominal surgery or irradiation. Although the risk of perforation is lower in open surgical insertion than in the blind or modified Seldinger technique [2], the risk of organ perforation is not completely avoidable if a hard stylet is used. Although the use of laparoscopic assistance lessens the risk of organ perforation [3], such beneficence of laparoscopy cannot be received by high-risk cases to which application of general anesthesia is impossible.

To make PDC catheter insertion procedures less invasive, we have developed a PDC insertion technique “flexible stylet method” using a unique equipment “alpha-replacer” as a stylet, and applied this new technique to high-risk patients.

A total of eight patients underwent “flexible stylet method” surgery at Fukushima Medical University Hospital. Patients’ profiles are summarized in Table 1. All patients were regarded that an application of standard surgery using hard stylet or laparoscopic approach under general anesthesia was unfavorable because of at least one of these reasons: (1) bleeding tendency (cases 1, 2, 4, 6), (2) suspected organic adhesion caused by prior abdominal surgery or irradiation (cases 2, 3, 5, 7, 8), (3) impaired cardiac function (cases 1, 2, 4, 5, 6), and (4) severe malnutrition represented by hypoalbuminemia (≤3.0 g/dL) (cases 4, 6, 7).

Details of flexible stylet method

Alpha-replacer

The alpha-replacer, which is developed in the late 1990s (JMS Co., Ltd., Tokyo, Japan, English homepage; http://www.jms.cc/english/index.html), is described in our previous report [4]. Briefly, the unique feature of the alpha-replacer is that this metal wire is usually soft, but becomes harder if coiled in the hand (Additional file 1). Such unique characteristic of alpha-replacer, or difference to ordinary guide-wire, is owing to its structure: The alpha-replacer comprises an inside “rope” and peripheral “spring” structure (Fig. 1). Precise detail regarding structure and characteristics of alpha-replacer is described elsewhere [4]. In Japan, alpha-replacer is widely used as a special wire-type equipment for transluminal replacement of a displaced peritoneal catheter.

The structure of alpha-replacer. The alpha-replacer comprises an inside “rope” and peripheral “spring” structure

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Insertion procedure

First, (a) a soft alpha-replacer covered with a PDC is inserted into the abdomen (Fig. 2). Next, (b) the wire is further inserted toward the Douglas pouch under fluoroscopic guidance. Then, (c) the alpha-replacer is slightly coiled in the hand, and the PDC is inserted following the slightly hardened wire. Procedures (b) and (c) are repeated alternately until the PDC tip is placed into the rectouterine pouch (Fig. 3). The representative maneuver (using simulator instead of real patient) is shown in Additional file 2, and real surgical field (of case 1) is shown in Additional file 3.

PDC insertion procedure using the alpha-replacer as stylet. a Flexible alpha-replacer is covered with PDC. b PDC is inserted into the peritoneal cavity

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Fluoroscopic image during PDC implantation (case 4). a PDC, accompanied by the alpha-replacer, is in the correct position in the minor pelvic space. b PDC after removal of the alpha-replacer. The PDC tip is in the correct position in the minor pelvic space (arrowhead)

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Consequence

The maneuver was completed successfully in all patients within 5 min except for case 7 (15 min) whose bowel adhesion was severe. Neither of the patients complained of pain during the procedure. After operation, the PDC tip was confirmed to be in the correct position in the Douglas pouch using abdominal X-ray in all cases (Fig. 4).

Representative radiography of peritoneal catheter after PDC implantation (case 1). The PDC tip is in the correct position in the Douglas pouch (arrowhead)

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In all cases, exchange of peritoneal dialysate was started the next day of PDC insertion. Temporal bloody effluent was observed for a few days in case 2. Besides, no complications were developed in all cases. After PDC insertion, the exchange of peritoneal dialysate was undergone without any trouble in all cases: neither dialysate leakage nor peritonitis was observed. All patients were discharged from the hospital after they mastered manipulation regarding peritoneal fluid exchange (6 to 37 days after PDC insertion).

Discussion

In this report, we adapted the new technique named “flexible stylet method” for the insertion of PDC to ESRD patients with high risks (organic adhesion, bleeding tendency, poor cardiac function, or malnutrition, or some of these). As a result, we completed successful maneuver without any severe complication.

The flexible stylet method described herein is considered superior to that using a hard stylet with regard to at least three points. The first point is safety. As alpha-replacer is very soft when the equipment itself is inserted toward the minor pelvic space (for alpha-replacer is not hardened at this timing), the risk of organ injury can be minimized. In fact, bowel injury due to alpha-replacer usage has not been reported until now [4, 5]. The second point is effectiveness. Although a fluoroscopically guided PDC insertion procedure using a fine guide-wire has already been reported [6, 7], the use of alpha-replacer that can be hardened when needed offers us more accurate placement of the PDC tip into the minor pelvic space. The third point is the simplicity of the procedure, as described herein.

The alpha-replacer is a unique equipment developed specifically for transluminal replacement of a displaced PDC, and has a double-spiral structure that confers unique characteristics to the equipment [4]. By coiling this in the hand, the free tip becomes hard, and release allows the free tip to become soft (Additional file 1). Proper adaptation of such characteristics in procedures should improve both the safety and success rate of PDC implantation.

The flexible stylet method is considered safe, effective, and simple. However, some limitations regarding this method remain. The first limitation is radiation exposure for fluoroscopic guidance. The second limitation is the somewhat complexity for the staffs of theater. The third limitation involves indications. We applied the present method to limited high-risk cases only. However, from the viewpoint of safety management, the flexible stylet method might be applied also to moderate or normal risk cases. The fourth and most important limitation is that the number of treated patient is relatively small (eight patients). The incidence of perforations reported in previous report is about 0.7 to 2.6 % (one complication versus 40 to 140 PDC insertion) [8]. Thus, larger number of patient might be required to prove “real” incidence of perforations regarding this flexible method.

As the mean age of ESRD patients initiated dialysis therapy is increasing year by year [9], potential risk concerning PDC insertion is thought to be also increasing. We believe that flexible stylet method contributes to wide utilization of peritoneal dialysis therapy in the era of an aging ESRD population.

In conclusion, the flexible stylet method as described herein offers effective and safe treatment, especially for high-risk cases.

We thank Thermo Co. (Tokyo, Japan) and Mrs. Kaoru Terawaki for the assistance of videotaping (appendices 1 and 2).

Authors’ contributions

HT made substantial contributions to the stabilization of the present procedure. NF made technical contributions to stabilize the present procedure. KA, AY, MN, and TK helped to draft the manuscript. All authors read and approved the final manuscript submitted for publication.

Authors’ information

HT is the director of Dialysis Center, Fukushima Medical University. NF, KA, and AN are the staff doctors of Dialysis Center, Fukushima Medical University. HT, NF, KA, and AN have provided medical and surgical care to many PD patients and have performed clinical research. MN is the director of the Department of Nephrology and Hypertension, Fukushima Medical University; he helped to draft the manuscript. TK is one of the developers of “alpha-replacer”; he helped to draft the manuscript.

Competing interests

The authors declare that they have no competing interests.

Affiliations

1. Dialysis Center, Fukushima Medical University School of Medicine, Fukushima, Japan

   • Hiroyuki Terawaki
   • , Naotaro Fukushima
   • , Keiko Aoyagi
   •  & Aya Nakajima

2. Department of Nephrology and Hypertension, Fukushima Medical University School of Medicine, Fukushima, Japan

   • Masaaki Nakayama

3. Research and Development, JMS Co., Ltd, Tokyo, Japan

   • Tomokazu Karino

Corresponding author

Correspondence to Hiroyuki Terawaki.

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