Imaging Tools to Guide Spinraza’s Use May Help Lower Complications
Adopting image-guided techniques may help physicians lower the risks of complications associated with the administration of Spinraza (nusinersen) in patients with spinal muscular atrophy (SMA), a study has found.
Physicians caring for these patients should be familiar with the different techniques and possible complications of treatment administration, researchers say.
The study, “Nusinersen injections in adults and children with spinal muscular atrophy: a single-center experience,” was published in the journal Diagnostic and Interventional Radiology.
Spinraza (nusinersen), marketed by Biogen, was the first disease-modifying treatment to be approved by the U.S. Food and Drug Administration, in December 2016, for the different forms of SMA. It works by increasing the production of the survival motor neuron (SMN) protein by the SMN2 “backup” gene, a gene similar to SMN1 but usually remains unaffected in SMA patients.
The medication is given by an injection directly into the spinal canal (intrathecal injection) to overcome its inability to cross the blood-brain barrier — a highly selective, semipermeable membrane that isolates the brain from the rest of the blood circulating in the body.
“While conventional LP [lumbar puncture] is feasible for many children and older patients without prior spine surgery, the anatomy is often challenging in patients with scoliosis with and without spinal fusion,” researchers wrote.
For that reason, several image-guided, non-image-guided, and port-delivered injection methods have been developed to administer Spinraza.
In the study, investigators at the University of Minnesota described their experiences with such methods while treating children and adults with different forms of SMA.
The retrospective study included data from 52 SMA patients — 24 women and 28 men, with a mean age of 25.5 years — who received a total of 265 Spinraza injections between February 2017 and September 2018.
Demographic and clinical data, as well as technical details of the injection procedures and associated complications were evaluated in all patients.
From the 265 injection procedures analyzed, 206 (77.9%) were performed under local anesthesia, 25 (9.4%) with moderate sedation, and 23 (8.6%) under general anesthesia.
A total of 37 patients received Spinraza injections through image-guided methods, which included computer tomography-guided transforaminal lumbar puncture (CT-TFLP) and fluoroscopy-guided lumbar puncture (FGLP). Conventional lumbar puncture was used to administer treatment to 16 patients.
From the 265 Spinraza injections, six (2.2%) led to post-lumbar puncture headache (PLPH) — one of the most common complications of lumbar puncture caused by the leaking of spinal fluid through the injection site — lasting more than one day and that required medical treatment. A total of 14 (5.2%) PLPHs resolved spontaneously on the same day they occurred.
Six of the 265 (2.2%) injections performed led to temporary soreness at the injection site that were also resolved without additional treatment.
Three patients opted to have an intrathecal reservoir placement — a surgical procedure in which a small device that works both as a reservoir and pump is implanted under the patient’s skin to administer Spinraza to the spine through a catheter.
One of the patients ended up having an infection after surgery, which led to meningitis. Once the meningitis was resolved, the patient underwent a new procedure to receive port-delivered injections of Spinraza. No additional complications were reported.
“[N]eurologists and radiologists play an important role in treatment of SMA patients and therefore should be familiar with different techniques and complications of drug administration,” the researchers wrote.
“Using good technique, it is possible to have very low complication rates even in this complex patient population, and various image-guided procedures can be a safe alternative to surgical approach, even in the most difficult cases,” they concluded.