Epidural catheter cutting: mechanisms and management.

To the Editor, Epidural catheter insertion can be followed by different complications appearing at its insertion, maintenance and removal. They can be distinguished in haemorrhagic, infectious and mechanical, when directly involving the device with different mechanisms: obstruction, kinking, knotting, displacement, migration, and breakage, or more frequently cutting [1]. Our experience, even limited to a single case, illustrates well this uncommon and unexpected event. A young man with no prior medical history, and a normal body mass index was scheduled for a radical cysto-prostatectomy for a bladder leio-myosarcoma. As usually, a tactile modified point epidural Thouy needle, 18 G, 3.5 in. length, was inserted with a right paramedian approach at the L1–L2 vertebral interlaminar space with the patient in a sitting position; a closed end, 3 holes, 20 G, 36 in. long polyamide catheter was inserted; the aspiration test was negative. At this moment, the patient presented a sudden vaso-vagal crisis, with involuntary contraction of its lumbar muscles. The Thouy's needle, with the catheter inside, was removed without difficulties. Unexpectedly the catheter was discovered sharply cut and missing 2 cm in its distal part. Considering the absence of local or neurological signs, the quick resolution of the vaso-vagal crisis, and the most probably extradural position of the catheter, it was decided to proceed with surgery, which providentially was successful. The first postoperative was uneventful, in particular without motor or sensitive neurological signs. On day 1 a Computed Tomography (CT) showed inside the right epidural space a tubular foreign body, 2 cm long, and exactly corresponding to the missed distal part of the catheter, without signs of other complications as haematoma, oedema or serous collection (Fig. 1). The conservative treatment was confirmed and a second CT control after three months did not show differences. The 6 months follow-up persisted negative for neurological signs. Considering the entire dynamics of the events, we suppose that the polyamid catheter was completely cut, just after its insertion, by the sharp bevel of the Thouy's, needle inadvertently pushed forward by the involuntary contraction of the spine muscle during the vaso-vagal crisis. Most probably, the vertebral transverse process and the yellow ligament acted as a plane of contra-resistance. Critically evaluating our experience we acknowledge that every not-urgent surgical procedure must be postponed when an epidural catheter, removed, is found damaged or missing in a part. On the base of the recent literature, we propose an algorithm in case of epidural catheter cutting or breakage (Fig. 2).The missed fragment must be localized by cross-sectional imaging tools, Computer Tomography (CT) or Magnetic Resonance [2]. When it is found intrathecal, or complicated by infection, subdural or epidural haematoma, or by a large blood effusion inside the spinal muscles, its quick extraction is mandatory. Similarly, when the missed fragment is in the sub-cutaneous tissue or close to lumbar fascia, its easy removal can be performed. On the contrary, if the fragment remains fixed in the epidural space, in absence of further complications, its extraction is not directly indicated, considering also the good tissue tolerance of the actual polyamide devices [3]; [4] ; [5]. To avoid this complication, we underline that, after insertion of the epidural catheter, the external needle must be carefully removed with a slow and continuous traction, avoiding any movement of re-pushing forward.