Withdrawal forces during removal of lumbar extradural catheters

Abstract

After performing successful continuous lumbar extradural conduction block, we investigated the effects of the extradural insertion technique (midline (M) or paramedian (P)) and patient position during extradural catheter removal (flexed lateral (L) or sitting (S)) on the force required to remove extradural catheters. One hundred parturients were allocated randomly to four groups: ML, MS, PL, PS. The results indicated that neither the midline nor paramedian approach affected withdrawal forces. However, more than 2.5 times as much force was required to remove the catheters when patients were in the flexed sitting compared with the lateral position (P < 0.005). For ease of removal of catheters from the lumbar extradural space we therefore strongly recommend the flexed lateral position.

Successful Removal of a Knotted Fascia Iliaca Catheter: Principles of Patient Positioning for Peripheral Nerve Catheter Extraction

“…In general, the approach is to minimize bony structure/soft tissue obstruction to reduce the force required to withdraw the catheter, thereby decreasing the likelihood of catheter breakage. Previous clinical investigations have demonstrated that the flexed position is superior for removal of an entrapped epidural catheter and that 2.5 times as much force is required to remove an epidural catheter in the flexed sitting compared with the flexed lateral position (5,7,18,19). The principle of "placing the patient in the position in which the catheter was inserted" when resistance is encountered during catheter removal is in part derived from these cases and investigations.…”

Management of the sheared epidural catheter: is surgical extraction really necessary?

“…(2) discontinuing application of force if the catheter begins to stretch and reapplying traction several hours later; (3) placing the patient in the same position as on insertion; (4) placing the patient in the lateral decubitus position if possible; (5) attempting to remove in extreme flexion if the previous interventions are not efficacious; (6) attempting extension if flexion fails; (7) attempting removal after injection of preservative-free normal saline through the catheter; (8) considering use of a convex surgical frame; (9) considering a CT scan to identify the etiology of entrapment; (10) considering leaving a retained epidural catheter in place in adult patients; (11) providing patient education regarding "red flags" to watch out for; and (12) neurosurgical consultation for all cases in which the catheter fragment is in the spinal canal.…”

“…Blackshear et al [2] suggested that less tension is required to remove an epidural catheter when the patient is in the lateral decubitus position as opposed to a sitting position. Another study showed that catheters inserted in the lateral position required less force when removed in the lateral position [3]. Morris et al [4] also suggested that significantly less force was required to remove an epidural catheter when the patient was placed in the same position as at the time of insertion.…”

On knots in epidural catheters: a case report and a review of the literature

“…Removal forces are lowest when the insertion and removal positions are similar. 27,28 If this fails, other patient positions and various degrees of lumbar flexion or extension can be tried.…”