Sub-arachnoid lumbar drainage is an important and frequently used procedure in the management of neurosurgical pathology in the setting of Intensive care. The indications include use in the management of intracranial subarachnoid haemorrhage, cerebrospinal leaks in both cranial and spinal pathology as well as for optimization of spinal cord perfusion in cardiothoracic surgery. Subarachnoid lumbar drains are routinely performed by both anaesthetic and neurosurgical specialities, where indicated. There are various choices of equipment from different manufacturers which are available in the market and proper knowledge and familiarity with equipment and technique is important to avoid complications from this procedure.
The complications which have been reported include infection, local haematomas, and injury to the neural structures, low pressure headaches and back pain. A less frequent, but well-documented procedural complication, is shearing of the catheter tip with in-situ retention. Shearing of the catheter tips are primarily related to faulty techniques which mainly results from pulling back or withdrawing the catheter after insertion into needle without withdrawing the needle and catheter simultaneously . Reported incidence ranges from 0-3% [1–3]. Reported complications of tip retention include migration of the tip leading to sub-arachnoid haemorrhage  and radicular pain at the site of the retained catheter fragment requiring surgery . Hence patients must be consented for such complications and clinicians should receive training for correct insertion technique and be made aware of potential pitfalls.
Here we report two cases in which despite proper technique, shearing of the catheter tip did occur. Both cases were performed with Codman Lumbar Drainage Catheter Kit II with preloaded Hydrophilic –coated Guide wire (Catalogue No. 82-1707).
Fig1. A-Soft Suture Tab, B-Male Luer-lock cap, C-Additional female Luer-lock connector, D-Lumbar catheter and Guidewire, E-Tuohy Needle
The first case was performed by the neurosurgical consultant in preparation for a trans-sphenoidal endoscopic pituitary hypophysectomy and the second case by a neurosurgical spinal fellow.
Both cases were associated with an easy introduction of the Tuohy needle with an atraumatic entry into the subarachnoid space with patients in the lateral position. Preloaded guidewire catheters were inserted. In case 1 minimal resistance was felt during initial insertion of the catheter into the subarachnoid space which subsequently felt easy to advance till the desired length. In both the cases after removal of the Tuohy needle some resistance was felt during removal of the guidewire. In both cases after removal of the guidewire no CSF was seen egressing from the drain. Even on gentle aspiration through the Luer-lock connector, no CSF flow was established. The catheter was gently withdrawn with repeated testing for CSF on aspiration. Finally, in both the cases, on removal of the catheter we found that the catheter tips had sheared and were then left in-situ. Patients were asymptomatic in both cases and no surgical intervention was required to retrieve the catheter tips.
Though guide wires are useful in introduction of the soft silicone lumbar drains into the spinal canal, there are some inherent pitfalls. The guidewire, if not loaded up to the tip of the catheter, leaves a segment of soft flimsy silicone tip over a more rigid distal guidewire end. When advanced in a narrow spinal canal this may allow the unsupported catheter tip to advance with the tip kinking over the advancing catheter.
Another possible mechanism is displacement of the guidewire extraluminally through the distal perforations of the silicone catheter. This can be reproduced in vitro by gently pushing and releasing the loaded silicone catheter when the guide wire is near the tip of the Tuohy needle, Fig 2. The subtlety of this movement may not be appreciated by the operator and would simulate the movement of the initial resistance that one feels when the tip first angles past the curve of the Tuohy needle. If at this stage the guidewire migrates extraluminally, it would carry a kinked catheter along with it distally and perhaps entangle the soft silicone with the more rigid guide wire. Removing the needle and withdrawal of the guidewire could shear the tip of the entangled soft catheter at the point of perforation into the dura or the thicker ligament flavum.
Inadvertent or intentional withdrawal of only the catheter in a loaded state through the needle makes it more susceptible to shear the soft silicone tip.
Though the study is too small to draw the conclusion that there is a higher incidence of catheter shearing with the use of guide wire, we aim to highlight a potential risk involved in the use of guide wires for lumbar subarachnoid drains.
1 Wong AI, Gao S, Bain MD, et al. Physical characteristics of catheters used for subarachnoid drainage. J Neurointerv Surg Published Online First: 2 July 2015. doi:10.1136/neurintsurg-2015-011864
2 Ransom ER, Palmer JN, Kennedy DW, et al. Assessing risk/benefit of lumbar drain use for endoscopic skull-base surgery. Int Forum Allergy Rhinol;1:173–7. doi:10.1002/alr.20026
3 Olivar H, Bramhall JS, Rozet I, et al. Subarachnoid lumbar drains: a case series of fractured catheters and a near miss. Can J Anaesth = J Can d’anesthésie 2007;54:829–34. doi:10.1007/BF03021711
4 Guppy KH, Silverthorn JW, Akins PT. Subarachnoid hemorrhage due to retained lumbar drain. J Neurosurg Spine 2011;15:641–4. doi:10.3171/2011.8.SPINE11387