We report a case of three-dimensional (3D) printing being used to solve a difficult bedside clinical problem and avoidance of substantial risk associated with alternative solutions. A 15-year-old male with advanced cystic fibrosis developed a small (~1mm) linear tear in his Percutaneous Endoscopic Gastrostomy (PEG) tube, approximately 40 mm from the skin surface. The patient’s advanced condition precluded replacement of the PEG tube under general anaesthetic. Attempts to manage the tear with adhesive tapes yielded limited success. 3D printing was used to create a bespoke sealing device overnight, rectifying the leak and allowing enteral feeding to recommence unimpeded. The device is functioning well, several months post-discharge of the patient.
- 3d printing
- palliative care
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The potential applications of three-dimensional (3D) printing in medicine is rapidly expanding. Current uses, including patient-specific implants and cutting guides, prosthesis and anatomical models are well described.1–3 We describe a case of 3D printing being used to rapidly solve a difficult bedside clinical problem.
Presented here is the case of a 15-year-old male with advanced cystic fibrosis (CF) lung disease with a forced expiratory volume in 1s between 20% and 25% predicted, a continuous oxygen requirement, overnight bilevel positive pressure ventilation and frequent (2–3 weekly) admissions for intravenous antibiotics. He had been assessed for lung transplant 3 years previously but had declined further assessment. He had been assessed for surgical replacement of a long-term indwelling venous access device the previous year but had been considered too high a risk for anaesthesia.
Five years previously, a Percutaneous Endoscopic Gstrostomy (PEG) tube (Corflo PEG Kit, Corpak Medsystems, Buffalo Grove, Illinois, USA) had been inserted endoscopically by a paediatric surgeon (JG) under general anaesthetic using the ‘pull’ technique described by Gauderer et al.4 The intragastric flange is an internal retention bumper with plastic foam. The PEG tube was critical to maintain caloric intake in this child with chronic anorexia and long-standing poor nutrition. His oral intake during the day was minimal so he was dependent on high calorie overnight feeds via the PEG tube. The child’s overall condition continued to worsen precluding an elective replacement of the PEG tube, as would be our normal practice. The integrity of the tubing was observed to be deteriorating to the point that a small (~1 mm) linear fracture developed in his PEG tube, causing a leak (figure 1, left, arrow).
When the PEG tube was noted to be leaking, the company supplying the device was contacted. They confirmed that no repair kit exists for the device, and replacement was advised. The internal flange keeping the PEG in situ required that the PEG change be performed under general anaesthetic. The paediatric surgeon who inserted the PEG 5 years previously was contacted and confirmed the patient’s current clinical status precluded general anaesthetic. The proximity of the tear to the skin surface (~40 mm) precluded the option to cut the PEG tube and fit a new enteral hub adapter. An option to cut the PEG close to the skin and allow the device to pass naturally through the gut had a low risk of causing obstruction; however, if such obstruction were to occur, it could prove fatal for this patient.5–7 The option of applying traction force to the PEG to cause a collapse of the internal flange and removal of the PEG via the stoma had the risk of significant pain for the patient, which is the principal reason its removal is normally done under general anaesthetic. There were two additional concerns voiced by the surgeon: first given the age of the PEG, there was a risk of tube breakage with retention of the flange and again (similar to the option of cutting the tube) a risk of subsequent obstruction.5–7 Second, despite the likelihood of a well-formed gastrocutaneous fistula being present, there is evidence in the literature of inadvertent intraperitoneal insertion of a replacement tube even in patients with mature tracts.8 9 The patient declined these options.
The PEG line had been maintained and managed for several days on an ad hoc basis by nursing staff using an adhesive surgical tape, which leaked consistently after 2 days and was repeatedly replaced. We consulted with members of the Design Factors research group in the University of Limerick and tasked them with exploring potential solutions. Overnight, a bespoke three-piece sealing device was designed and fabricated using a multimaterial 3D printer (figure 1, right).
The design of the sealing device, which is based on the principles employed in haemostasis valves, took approximately 1.5 hours to realise and evaluate in a CAD package (Solidworks). The sealing device was printed on a Connex 500 3D printer (Stratasys) using the Med610 material, which is a USP Class IV approved material for prolonged skin contact. Total printing time was 1 hour, with an additional hour for cleaning and preparation of the components. The total material cost of the device was approximately €4, representing a major cost saving in providing a clinical solution.10
Figure 2A is an exploded view of the three components: the top cap, bottom cap and sealing cuff. The sealing cuff is composed of a rigid cylinder with a soft rubber O-ring at each end, printed as one component. Figure 2B shows a section view of the device. Figure 2C shows the location of the sealing cuff in relation to the linear tear.
As the top cap is screwed into the fully locked position, both the O-rings are compressed between the body and the inner sealing cuff. This provides the proximal and distal sealing around the tear. The rigid tube between the O-rings prevents the PEG tube from distending, reducing the risk of further dissection. The device was precision made to fit tightly over the PEG tube and was positioned over the fractured section of the tube. The device was designed to fit a 12 Fr PEG tube as originally fitted to the patient; however, on attempting to apply the sealing device, it was discovered that the original PEG tube had swollen to ~15 Fr. A larger version of the device was printed and fitted to the PEG tube in less than 4 hours.
On fitting the sealing device, the PEG tube was immediately ready for use, and the patient was recommenced on his full supplement overnight feeding regime.
The tube has not since leaked, and no extension of the fracture in the tube has been observed. In all, the completed, functional device was fitted less than 24 hours after initial discussions between the clinical and design teams. The patient was discharged and the device is functioning well, several months postdischarge. If the tube had continued to leak, it would have certainly delayed the discharge. While 3D printing has been employed previously to provide bespoke solutions for exceptional cases,11 we believe this is among the first case report of 3D printing being used to resolve a complicated bedside clinical issue, thus avoiding the risks associated with alternative options. Our hope is that with new CF transmembrane conductance regulator modulators coming on stream, this teenage boy’s clinical status will improve to the point where he could have the tube replaced by the surgical team, with anaesthetic support.
The contents of this manuscript were presented in abbreviated form as a poster at the Irish Thoracic Society Annual Scientific Meeting, November 2017.
Contributors KJOS and BL drafted the original manuscript. KJOS, AOS and LOS were responsible for the design and manufacture of the sealing device. NP, BL and JG were the responsible clinical staff for the patient concerned. CD helped to prepare the manuscript.
Funding This research received no specific grant from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent Guardian consent obtained.
Provenance and peer review Not commissioned; externally peer reviewed.
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