Evaluation of usefulness of scintigraphic imaging in diagnosis of intrathecal drug delivery system malfunction - a preliminary report

Loss of effectiveness with an implanted drug delivery system for intrathecal pain therapy due to corrosion

INTRODUCTION

Intrathecal drug delivery is an established invasive treatment option. Most common complication is catheter malfunction, which can lead to overdose or withdrawal.

CASE PRESENTATION

A 61-year-old female patient underwent an elective replacement of an intrathecal drug delivery pump. The patient complained about a loss of effectiveness over the past 2 years. Intraoperatively, a white mass corresponding to morphine precipitation in the pump pocket was found, which appeared to be due to corrosion at the pump-catheter connection site.

CONCLUSIONS

Recommendations on how to deal with the decreasing effectiveness of intrathecal drug delivery and on intraoperative catheter handling are provided.

The leptomeninges as a critical organ for normal CNS development and function: First patient and public involved systematic review of arachnoiditis (chronic meningitis)

BACKGROUND & IMPORTANCE

This patient and public-involved systematic review originally focused on arachnoiditis, a supposedly rare "iatrogenic chronic meningitis" causing permanent neurologic damage and intractable pain. We sought to prove disease existence, causation, symptoms, and inform future directions. After 63 terms for the same pathology were found, the study was renamed Diseases of the Leptomeninges (DLMs). We present results that nullify traditional clinical thinking about DLMs, answer study questions, and create a unified path forward.

METHODS

The prospective PRISMA protocol is published at Arcsology.org. We used four platforms, 10 sources, extraction software, and critical review with ≥2 researchers at each phase. All human sources to 12/6/2020 were eligible for qualitative synthesis utilizing R. Weekly updates since cutoff strengthen conclusions.

RESULTS

Included were 887/14286 sources containing 12721 DLMs patients. Pathology involves the subarachnoid space (SAS) and pia. DLMs occurred in all countries as a contributor to the top 10 causes of disability-adjusted life years lost, with communicable diseases (CDs) predominating. In the USA, the ratio of CDs to iatrogenic causes is 2.4:1, contradicting arachnoiditis literature. Spinal fusion surgery comprised 54.7% of the iatrogenic category, with rhBMP-2 resulting in 2.4x more DLMs than no use (p<0.0001). Spinal injections and neuraxial anesthesia procedures cause 1.1%, and 0.2% permanent DLMs, respectively. Syringomyelia, hydrocephalus, and arachnoid cysts are complications caused by blocked CSF flow. CNS neuron death occurs due to insufficient arterial supply from compromised vasculature and nerves traversing the SAS. Contrast MRI is currently the diagnostic test of choice. Lack of radiologist recognition is problematic.

DISCUSSION & CONCLUSION

DLMs are common. The LM clinically functions as an organ with critical CNS-sustaining roles involving the SAS-pia structure, enclosed cells, lymphatics, and biologic pathways. Cases involve all specialties. Causes are numerous, symptoms predictable, and outcomes dependent on time to treatment and extent of residual SAS damage. An international disease classification and possible treatment trials are proposed.

Isotopic Scintigraphy in Intrathecal Drug Delivery Failure: A Single-Institution Case Series

Background

The aim of this study was to assess the feasibility and diagnostic accuracy of an optimized ¹¹¹Indium‐diethylenetriamine‐penta‐acetic‐acid single‐photon‐emission computed tomography (CT) (¹¹¹In‐DTPA SPECT‐CT) examination in patients with suspected intrathecal drug delivery (ITDD) failure.

Materials and Methods

Retrospective analysis of routinely collected observational data from a case series of patients in the setting of the academic Center for Pain Medicine, Departments of Radiology and Nuclear Medicine and Neurosurgery. Twenty‐seven patients participated between January 2014 and January 2019. Thirty‐six optimized examinations including standardized pump flow rate with additional SPECT‐CT imaging and a stepwise standardized analysis were performed. A 10 mL mixture of medication and 20 MBq 111In‐DTPA was injected into the pump reservoir. Planar and SPECT‐CT images were acquired at 24, 48, and 72 hours (h) after injection and at 96 hours and/or seven days, if needed. All images were reassessed by the first two authors using an optimized procedure.

Results and Conclusions

Twenty‐two abnormalities were identified in 21 examinations, with these abnormalities consisting of leakage (n = 7), spinal catheter obstruction (n = 7), and cerebrospinal fluid flow obstruction (n = 8). Interventions (n = 19) confirmed the cause of ITDD failure. A false‐positive finding at follow‐up (n = 1) and a false‐negative finding (n = 1) were encountered. Sensitivity was 95% (20/21) and the specificity 93% (14/15). A significant difference (p < 0.001) was found between the accuracy of the conventical and the optimized analysis. The optimized ¹¹¹In‐DTPA SPECT‐CT examination is a powerful diagnostic tool for detecting the cause of ITDD failure.

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.

Isotopic Scintigraphy Coupled With Computed Tomography for the Investigation of Intrathecal Baclofen Device Malfunction

OBJECTIVE

To assess the potential use of indium-111 diethylenetriamine pentaacetic acid ((111)In-DTPA) scintigraphy coupled with computed tomography (CT) for the investigation of intrathecal baclofen (ITB) device malfunction.

DESIGN

Retrospective study of a case series of patients.

SETTING

Neurosurgical and physical and rehabilitation medicine departments.

PARTICIPANTS

Patients (N=7) with reduced ITB effectiveness in whom prior conventional radiographs were inconclusive.

INTERVENTION

Nine (111)In-DTPA scintigraphic studies and 8 CT scans. Planar acquisitions were followed by tomoscintigraphy combined with CT.

MAIN OUTCOME MEASURE

Progression of the radiotracer in the pump, catheters, and in the subarachnoid space.

RESULTS

In 7 cases, scintigraphy coupled with CT showed leakage behind the pump, lack of activity outside the pump reservoir, abrupt interruption of activity in the catheter, or abnormal distribution of the radiotracer, thus demonstrating that the drug did not reach its target. Surgical revision confirmed these findings in 5 cases. In 1 case, combined imagery ruled out device dysfunction. In the remaining case, only planar acquisitions were performed, showing correct diffusion of the radiotracer.

CONCLUSIONS

The combination of scintigraphy and CT provides simultaneous functional and anatomic imagery of the device. The slow infusion of the radioisotope mimics the diffusion of baclofen, and this could be a useful method to explore intrathecal device malfunction. Further studies are required to compare scintigraphy coupled with CT, to radiopaque injection followed by fluoroscopy or CT.