We report spontaneous extrusion of catheter from the spinal canal, which is a very unusual complication of intrathecal baclofen therapy. It is likely that repeated bending forwards and straightening of torso for pressure relief and during transfers from wheelchair, contributed to extrusion of catheter from the spinal canal in this patient. After extruding out of the spinal canal, the catheter got coiled in paravertebral space, where the catheter had been anchored firmly to intermuscular septum. Spontaneous extrusion of catheter from the spinal canal is unlikely to occur in profoundly disabled individuals, who do not actively move their trunk. For example, there may be individuals with advanced multiple sclerosis, who are confined to the chair and who do not have the ability to bend forwards and then straighten the torso for pressure relief or, perform unassisted transfers from the wheel chair to bed, toilet seat, or car. These patients are unlikely to develop extrusion of catheter from spinal canal if they undergo implantation of Medtronic pump for intrathecal baclofen therapy.
Abrupt withdrawal of intrathecal baclofen therapy can result in a life-threatening syndrome (high fever, altered mental status, profound muscular rigidity that may sometimes progress to fatal rhabdomyolysis). The intrathecal baclofen withdrawal syndrome is clinically and pathophysiologically distinct from autonomic dysreflexia, malignant hyperthermia, and neuroleptic-malignant syndrome. [6
]. This patient did not develop intrathecal baclofen withdrawal syndrome at any stage. Probably, the catheter came out of thecal space very gradually over a period. Even when the catheter was extruded completely from thecal space, it is likely that a fibrous channel existed between the tip of the catheter and thecal space, which provided an entry path to the infused drug to reach thecal space. This would explain prompt relief of spasticity when the dose of intrathecal baclofen was increased.
The tip of catheter was placed at T-8 level during the second operation. Initially, the tip of catheter was located at T-10 level. Burns and Meythaler [7
] emphasised the importance of the level of intrathecal catheter placement to achieve satisfactory control of spasticity. Placement of the tip of the intrathecal catheter at the T-6 / T-7 level was associated with greater relief of upper-extremity spasticity without loss of effect on the lower extremities. The mean dosages of baclofen in children with spastic tetraparesis, in whom intrathecal catheter was placed at the T-6 / T-7 level with fluoroscopic guidance, were lower compared with mean dosages when the catheter tip had been placed at the T-11 / T-12 level. No morbidity related to the more rostral location of the catheter was observed in the children, in whom the catheter tip had been placed at the T-6 / T-7 level. [8
This case illustrates that catheter-pump malfunction should be excluded before ascribing resurgence of spasticity to drug tolerance, or other co-existing conditions such as bladder stones, particularly in SCI patients, whose spasms had been well controlled previously with intrathecal baclofen therapy. Vesical calculi acted as red herring for recurrence of spasms in this patient. In retrospect, we observed that vesical calculi were present even in the X-rays taken on day 487 when the patient had adequate control of spasticity and the pump was delivering baclofen satisfactorily with the tip of catheter located at T-10 level. (Figure ). Had the X-ray taken on day 689 been available in an easily retrievable format for repeated viewing by different health professionals, it is likely that at least one of us would have noticed spontaneous extrusion of catheter from the spinal canal and we would have implemented corrective measures expeditiously.
Figure 8 X-ray of pelvis taken on day 487 shows vesical calculi. When this X-ray was taken, the patient had adequate control of spasticity despite the presence of bladder stones because the pump was delivering baclofen satisfactorily with the tip of catheter located (more ...)
It is possible that some physicians might have encountered similar mishap after implantation of baclofen pump, but have not published the adverse events for fear of recrimination. We favour voluntary reporting and dissemination of information on adverse events related to clinical procedures and medical implants [9
]. Quite often, mishaps occur due to system errors and therefore, apportioning blame to individual health professionals should be avoided. A joint team approach by health professionals belonging to various medical disciplines, which is strengthened by frequent, informal and honest
discussions of a patient's clinical condition, is likely to reduce delays in diagnosis and medical errors in spinal cord injury patients.