A Collection of Complications Related to Drugs or Devices
Intermittent Coma in a Patient With an Intracranial Intrathecal Baclofen Pump Catheter
Kathleen E. Knudson, MD, and Donald C. Shields, MD, PhD
The George Washington University, Washington, DC
Our patient was a 66-year-old woman who had previously received diagnoses of multiple sclerosis in 1992 and Parkinson disease in 2004. She had developed progressively worsening spasticity that had left her wheelchair-bound for the past 5 years.
History. For her spasticity, she had undergone placement of an intrathecal baclofen pump by an unaffiliated surgeon. After placement of the baclofen pump, she stated that her spasticity had improved. However, she also began to develop episodes of somnolence, wherein she became unarousable for 6 to 12 hours. Per witnesses, she could not be awakened even with vigorous, painful stimuli during these episodes; then, she would awaken as if from sleep. When these episodes first occurred, she had been taken to the local emergency department on multiple occasions, but no etiology could be ascertained. Later, these episodes became progressively more frequent, occurring almost weekly.
Physical examination. On examination, she showed evidence of spasticity and increased tone in her upper and lower extremities without fasciculations or abnormal movements. The remainder of the neurologic examination findings were unremarkable.
Diagnostic tests. A computed tomography (CT) scan of the head (Figure) showed the intrathecal baclofen pump catheter terminating ventral to the brainstem, at the level of the pons, just posterior to the clivus. There was no prior imaging available from the initial surgery to determine whether this was the original placement or whether the catheter had migrated. After discussion with the patient of the risks and benefits of surgical intervention, the patient elected to undergo surgical retraction of the catheter.
Figure. Noncontrast head CT with sagittal reconstruction showing the intrathecal baclofen pump catheter tip in the CSF space ventral to the brainstem.
During surgery, C-arm fluoroscopy was used to visualize the catheter tip. The prior surgical site on her back was opened, and the sutures holding the catheter anchor were cut. We retracted the catheter gently under direct fluoroscopic guidance; it moved freely without evidence of tethering. The tip was retracted to the level of C7 vertebra, and a second anchor was sutured in place to prevent migration.
Outcome of the case. The patient was followed closely as an outpatient after her surgery. She had 3 short episodes of somnolence within the first month after surgery; however, she did not have any further episodes for the following 12 months. She continued to report good relief of her spasticity, and neurologic examination findings remained unchanged from those of the preoperative examination. Postoperative radiographs revealed stable position of the catheter tip at the cervicothoracic junction.
Discussion. Intrathecal baclofen has been increasingly used for the treatment of spasticity in children and adults. It has been shown to reduce spasticity and contractures and improve functional ability. However, complications associated with the surgical procedure, device, or drug have been reported.1 The most common complications are infection, hematoma, and cerebral spinal fluid (CSF) leak.2 Complications related to the catheter commonly are catheter migration, kinking, disconnection, or breakage. Catheter-related complications are most common within the first year of implantation.2
Common complications related to the pump are rare and are largely due to misplacement or migration of the pump. To our knowledge, this is the first report of a patient with symptoms from a baclofen pump catheter tip that was found at the level of the brainstem.
A definitive explanation for our patient’s episodes of somnolence remains unclear. Similar episodes of temporary coma have been reported rarely. Anderson and colleagues3 reported delayed postoperative coma in 5 children following surgery for insertion of an intrathecal baclofen pump. They suggested that the cause of these episodes was likely inadvertent administration of an intrathecal baclofen bolus. In our patient’s case, there was no evidence of her having received intrathecal baclofen boluses prior to symptom onset, but the location of the catheter tip allowed for possible mechanical trauma and delivery of more-concentrated medication in the vicinity of the brainstem. Of note, baclofen pump catheters have since been placed in the cervical spine4 and intraventricular space5 without provocation of somnolence or unresponsiveness.
- Borrini L, Bensmail D, Thiebaut J-B, Hugeron C, Rech C, Jourdan C. Occurrence of adverse events in long-term intrathecal baclofen infusion: a 1-year follow-up study of 158 adults. Arch Phys Med Rehabil. 2014;95(6):1032-1038.
- Motta F, Antonello CE. Analysis of complications in 430 consecutive pediatric patients treated with intrathecal baclofen therapy: 14-year experience. J Neurosurg Pediatr. 2014;13(3):301-306.
- Anderson KJ, Farmer JP, Brown K. Reversible coma in children after improper baclofen pump insertion. Paediatr Anaesth. 2002;12(5):454-460.
- Ughratdar I, Muquit S, Ingale H, Moussa A, Ammar A, Vloeberghs M. Cervical implantation of intrathecal baclofen pump catheter in children with severe scoliosis. J Neurosurg Pediatr. 2012;10(1):34-38.
- Turner M, Nguyen HS, Cohen-Gadol AA. Intraventricular baclofen as an alternative to intrathecal baclofen for intractable spasticity or dystonia: outcomes and technical considerations. J Neurosurg Pediatr. 2012;10(4):315-319.