Cyclic Hypertonia and Hypotonia Associated with Intrathecal Baclofen Pumps: Findings and Treatments.

Abstract

Background: Intrathecal baclofen therapy and baclofen pumps can lead to complications, including recurrent cycles of alternating hypertonia and hypotonia. The causes and optimal treatments for this issue remain unclear. This study reviews presentations, radiologic and surgical findings, treatments, and outcomes in cases of cyclic hypertonia/hypotonia.

Methods: We reviewed patients with baclofen pumps treated at our hospital from 1998 to 2024 who developed cyclic hypertonia/hypotonia. Data collected included patient sex, etiology and type of tone abnormality, age at pump placement, age and weight at symptom onset, infusion rate and type at onset, side port access and catheter dye study results, treatments, surgical findings, and outcomes.

Results: We identified 15 cases in 14 patients (10 females, 71%; 4 males, 29%). Among 248 patients with baclofen pumps, 38% were female. Females were significantly more likely to develop cyclic hypertonia/hypotonia (p<0.01). The mean age at pump implantation was 10.2 years, and the mean time from last pump surgery to symptom onset was 645 days. All patients received enteric baclofen initially; 14 also had pump rate adjustments. Three patients improved without surgery, and one died during a hypotonia episode. Side port access showed patent catheters in 7 of 8 cases, with 6 of these showing good intrathecal dye dispersion. Surgery was performed in 11 cases, including two surgeries in 6 cases. Nine patients had pump replacements; 8 also had catheter revisions. Surgical findings included catheter kinks in 4 cases (36% of surgical cases) and leaks in 5 cases (45%), with 4 leaks at the pump-connector catheter connection. Six of 11 partial revisions (55%) and all 5 complete catheter replacements (100%) resulted in symptom resolution without recurrence. Replacing the pump-connector segment resolved symptoms without recurrence in 4 of 5 patients with leaks at this site. Overall, all patients undergoing surgery experienced symptom improvement without recurrence after one or two revisions.

Conclusion: Adjusting pump rates and adding enteric baclofen may help some patients with cyclic hypertonia/hypotonia. If a leak at the pump-connector catheter segment is identified, segment replacement should be considered. When partial revisions fail, complete catheter replacement appears more effective, especially as a second surgery. Cyclic hypertonia/hypotonia is a treatable complication of baclofen pumps.