Managing loss of intrathecal baclofen efficacy: Review of the literature and proposed troubleshooting algorithm

Baclofen Stability up to One Year in In Vivo Intrathecal Infusion Pumps

OBJECTIVES

Commercial intrathecal baclofen treatment (ITBT) infusion pumps are recommended to be refilled within a maximum of 180 days, thus necessitating at least twice-yearly outpatient visits and refill injections. In particular, pumps with 40-mL reservoir volumes would allow much longer refill intervals. We investigated baclofen stability in active implanted ITBT infusion pumps in vivo with refill intervals up to 367 days to study the feasibility of lengthening refill intervals beyond six months.

MATERIALS AND METHODS

We obtained 25 baclofen samples from 19 patients receiving ITBT with varying pump refill intervals. All patients had a baclofen infusion system delivering undiluted 2 mg/mL baclofen at continuous rates of 96.1 to 673.7 μg/d with a concentration of 2.002 mg/mL. Baclofen concentrations of the infusate samples acquired during the refill procedures were analyzed using a validated high-performance liquid chromatography with diode-array detection (HPLC-DAD) assay, later complemented with repeat assay with pH and physical measurements. We also present the validation data of the HPLC-DAD assay.

RESULTS

During the mean refill interval of 247 days (SD 90, range 54-367 days), the mean change in baclofen concentration was -0.0156 mg/mL (-0.8%, SD 0.14, range -0.30 to 0.32 mg/mL, paired t-test p = 0.57, t24 = 0.57). Only a low negative correlation was found between the baclofen concentration and the refill interval (Pearson's r = -0.32, p = 0.12).

CONCLUSIONS

We could not show a significant change in baclofen concentration over the time studied; 2 mg/mL baclofen ITBT refill intervals could be lengthened to up to one year-the theoretical maximum refill interval in our cohort would have been 489 days. Further studies with larger sample sizes and other baclofen brands are warranted.

Complications of Intrathecal Baclofen Pump Therapy: An Institutional Experience from Saudi Arabia

The intrathecal baclofen pump (ITB) is one of the advanced treatment options in the management of spasticity. This retrospective cohort study was conducted to identify the complications of ITB treatment at a tertiary care rehabilitation facility. Various demographic and technical factors were analyzed, which are less often reported in the literature. All patients with ITB who had their refill at the ITB clinic between November 2019 and March 2020 were included. Of 48 patients, 17 patients had 18 (37.5%) ITB-related complications. Catheter-related complications were most common, whereas loss of efficacy (16.7%) and baclofen withdrawal (14.5%) were the most common outcomes of complications. Only catheter occlusion had a significant relationship with the pattern of spastic quadriparesis (p = 0.001). Gender, rehabilitation diagnosis, patients' residence, and facility of ITB placement did not have significant association. Similarly, age, distance from hospital, disease onset, ITB therapy duration, and baclofen dose were not statistically significant in relation to ITB-related complications.

The role of selective dorsal rhizotomy in the management of post-traumatic spasticity: systematic review

There is a huge burden of patients suffering from trauma-induced disabling spasticity the world over. There are surprisingly few modalities of treatment with a sustained, proven benefit which can be offered to such patients. Selective dorsal rhizotomy (SDR) has been used with proven success in treating spasticity in patients of cerebral palsy, both in children and in adults. The rationale behind using the procedure in post-traumatic cases is reviewed, along with the cases reported till date in the world literature. The indications, surgical procedure used, outcome and complications, if any, are described. Most of the cases described in the literature have shown a favourable outcome with minimal complications. SDR can become an important tool in the armamentarium of the clinician treating this condition.

Evaluation of intrathecal baclofen delivery system malfunction by computed tomography scan

AIM

To describe the computed tomography (CT) findings encountered when catheter patency is questionable. The role of CT in directing treatment is evaluated.

METHOD

Records of children with intrathecal baclofen pump management were reviewed. Only patients with CT evaluation who had revision pump/catheter surgery were included.

RESULTS

From 295 patients, 27 had CT contrast study; in three of them, baclofen could not be aspirated and the procedure was stopped, eight had normal scan and did not need surgery and 16 patients were reported. Four patients had normal CT (free contrast formed a perfect crescent shape), and had surgery because the pump battery was close to expiration. Five patients had inadequate fluid pooling (fluid was seen without a crescent shape). Five patients had fluid leak (fluid was seen around the pump or in the lumbar canal below catheter entrance level or outside the canal in the lumbar region). Two patients had catheter occlusion (fluid loculation around the catheter tip with no free flow).

INTERPRETATION

CT contrast study is safe and effective for locating defects in intrathecal baclofen delivery system. When catheter patency is questionable, CT plays an important role in directing the next step of management.