Computed-tomography-guided transforaminal intrathecal nusinersen injection in adults with spinal muscular atrophy type 2 and severe spinal deformity. Feasibility, safety and radiation exposure considerations

A horizontal and perpendicular interlaminar approach for intrathecal nusinersen injection in patients with spinal muscular atrophy and scoliosis: an observational study

BACKGROUND

Lumbar puncture is challenging for patients with scoliosis. Previous ultrasound-assisted techniques for lumbar puncture used the angle of the probe as the needle trajectory; however, reproducing the angle is difficult and increases the number of needle manipulations. In response, we developed a technique that eliminated both the craniocaudal and lateromedial angulation of the needle trajectory to overall improve this technique. We assessed the feasibility and safety of this method in patients with scoliosis and identify factors related to difficult lumbar puncture.

METHODS

Patients with spinal muscular atrophy and scoliosis who were referred to the anesthesia department for intrathecal nusinersen administrations were included. With a novel approach that utilized patient position and geometry, lumbar puncture was performed under ultrasound guidance. Success rates, performance times and adverse events were recorded. Clinical-demographic and spinal radiographic data pertaining to difficult procedures were analyzed.

RESULTS

Success was achieved in all 260 (100%) lumbar punctures for 44 patients, with first pass and first attempt success rates of 70% (183/260) and 87% (226/260), respectively. Adverse events were infrequent and benign. Higher BMI, greater skin dural sac depth and smaller interlaminar size might be associated with greater difficulty in lumbar puncture.

CONCLUSIONS

The novel ultrasound-assisted horizontal and perpendicular interlaminar needle trajectory approach is an effective and safe method for lumbar puncture in patients with spinal deformities. This method can be reliably performed at the bedside and avoids other more typical and complex imaging such as computed tomography guided procedure.

Unilateral interlaminar fenestration on the convex side provides a reliable access for intrathecal administration of nusinersen in spinal muscular atrophy: a retrospective study

BACKGROUND

As the first gene therapy for spinal muscular atrophy (SMA), nusinersen is supposed to be administrated via intrathecal injection regularly for a lifetime. However, for SMA patients with severe spinal deformities, bony fusion following posterior spinal instrumentation sets great obstacles for the application of nusinersen. Therefore, efforts have been devoted to the exploration of appropriate approach for nusinersen administration. This study aims to evaluate the safety and reliability of unilateral interlaminar fenestration on the convex side during spinal fusion surgery for intrathecal nusinersen injection in SMA.

RESULTS

SMA patients receiving posterior spinal fusion and interlaminar fenestration in Peking Union Medical College Hospital from January 2020 to October 2021 were retrospectively analyzed. 13 patients were included. Of the 13 patients, 10 were classified into SMA type II and 3 into SMA type III. Distal fusion to pelvis was undertaken in 11 patients; while L5 was selected as the lowest instrumented vertebra in the other 2 patients. All patients received interlaminar fenestration on the convex side only with an area of about 15 mm × 20 mm. Fenestration at L2-L3 level was performed in 6 patients; while L3-L4 level was selected for windowing in the remaining 7 patients. 9 of the 13 patients received lumbar puncture and intrathecal nusinersen administration during the 1-year follow-up, with an accumulative total of 50 times. All injections were performed successfully under ultrasound guidance, with no one transferred to radiographic assistance. No severe complications occurred after injection.

CONCLUSIONS

In SMA with severe scoliosis planning to receive posterior spinal fusion, unilateral lumbar interlaminar fenestration on the convex side provides a feasible and reliable access for intrathecal nusinersen administration after surgery.

Modified nusinersen intrathecal injection method: inclusion of a septal needle-free closed infusion connector

Objective

Nusinersen, an extremely expensive biologic drug (around 100,000 US$ per dose) that needs to be administered intrathecally, is approved for the treatment of 5q-spinal muscular atrophy (SMA). Because of the low muscle tone of the back muscles of pediatric SMA patients, especially type 1 SMA patients, the safe, effective, and fast execution of sheath injection is needed. Therefore, a modified intrathecal injection method was developed accordingly. This paper aims to describe the applicability and safety of this modified method.

Methods

The modified intrathecal injection method (MIIM) mainly includes a septal needle-free closed infusion connector between the lumbar puncture needle and the syringe, besides the procedures of routine lumbar puncture. Its applicability and safety were evaluated through clinical observation.

Results

A total of 92 children with SMA have successfully received nusinersen treatment at our hospital using the modified method since 2019 without obvious adverse events related to the modified injection method. Based on the clinical feedback of operators, the advantages of the modified method include successfully injecting the total dose of nusinersen with constant injection rate and a more stable fixation of the puncture needle, as well as making the operator more relaxed. However, compared with the routine method, the procedure of the modified method has additional steps.

Conclusion

The modified intrathecal injection method is an effective and safe method to inject nusinersen when weighing the pros and cons, and it may also be used for administering intrathecal injections of other expensive medicines or for patients with other strict requirements for intrathecal injection.

Ultrasound-guided interlaminar approach for nusinersen administration in patients with spinal muscular atrophy with spinal fusion or severe scoliosis

BACKGROUND

Intrathecal injection of medications can be challenging in spinal muscular atrophy (SMA) patients with severe scoliosis or after spine surgery. Here we report our experience with real-time ultrasound (US)-guided intrathecal administration of nusinersen in patients with SMA.

METHODS

Seven patients (six children and one adult) with either spinal fusion or severe scoliosis were enrolled. We performed intrathecal injections of nusinersen under US guidance. The efficacy and safety of US-guided injection were explored.

RESULTS

Five patients had undergone spinal fusion, while the other two presented severe scoliosis. Success was achieved in 19/20 lumbar punctures (95%), 15 of which were performed through the near-spinous process approach. The intervertebral space with a designated channel was selected for the five postoperative patients, while the interspaces with the smallest rotation angle were chosen for the other two patients with severe scoliosis. In 89.5% (17/19) of the punctures, the number of insertions was no more than two. No major adverse events were observed.

CONCLUSION

Given its safety and efficacy, real-time US guidance is recommended for SMA patients with spine surgery or severe scoliosis, and the near-spinous process view can be used as a interlaminar puncture approach for US guidance.

Current treatments of spinal muscular atrophy in adults

Spinal muscular atrophy (SMA) is a rare autosomal recessive neuromuscular disorder related to motor neuron degeneration. SMA patients present generally severe muscular weakness and atrophy, which can reduce life expectancy and lead to severe functional disability. In recent years, the management of this condition has been revolutionized by the development of innovative therapies that target alternative splicing of pre-messenger SMN2 RNA by antisense oligonucleotides or small molecules and by the approval of the first vector-based SMN1 gene therapy. The high significance of the trials in children led to fast-tracking of these therapies to all SMA patients despite the absence of data in adults. Real-life data are progressively providing a better understanding of the expected benefits and tolerability. They also highlight the difficulties of evaluating these patients and the need to take into account the patients' reported expectations and outcome. A review of the main data in adult patients is presented. The mechanisms of action of these innovative therapies are discussed as well as the limits of evaluations of these therapies in adults with longstanding severe amyotrophy.

Cone-beam computed tomography guided nusinersen administrations in adult spinal muscular atrophy patients with challenging access: a single- center experience

BACKGROUND

The challenging anatomic predispositions in adult patients with spinal muscular atrophy (SMA) preclude the conventional lumbar punctures. Consequently, an introduction of alternative method for intrathecal delivery of nusinersen is required. Cone-beam CT (CBCT) allows volumetric display of the area of interest, pre-procedural planning and real time needle guidance which results in accurate anatomic navigation. The aim of the study was to evaluate technical success, safety, and feasibility of CBCT lumbar intrathecal delivery of nusinersen in the adult SMA patients with challenging anatomical access.

PATIENTS AND METHODS

Thirty-eight adult SMA patients were treated in our institution. Patients with challenging access were selected by multidisciplinary board for image guided administration of nusinersen either due to implantation of the posterior fusion instrumentation, severe scoliosis defined as Cobb's angle > 40º or body mass index over 35. Technical success, radiation exposure and occurrence of adverse events were assessed.

RESULTS

Twenty patients were selected, and 108 CBCT-guided procedures were performed. Each patient underwent at least 4 administrations. Transforaminal approach was performed in 82% of patients. The technical success was 100%, with primary success of 93.5%. The median radiation effective dose of the administrations was 5 mSv, the mean value equalled 10 mSv. Only mild adverse events were reported in the study.

CONCLUSIONS

CBCT-guided lumbar intrathecal administrations of nusinersen in an adult SMA population with challenging access was feasible and safe image guided method.

Intrathecal Administration of Nusinersen Using the Ommaya Reservoir in an Adult with 5q-Related Spinal Muscular Atrophy Type 1 and Severe Spinal Deformity

Spinal muscular atrophy (SMA) is a hereditary neuromuscular disorder, typically caused by survival motor neuron 1 (SMN1) gene deletion in chromosome 5q resulting in loss of SMN protein. SMA type 1 progresses rapidly leading to increased mortality usually before the age of 2 years. Nusinersen, the first approved disease-modifying treatment for all 5q-SMA types and ages, is an antisense oligonucleotide administered intrathecally via repeated lumbar punctures. However, adult SMA patients typically present with severe scoliosis and spinal deformity. We present a 28-year-old patient with SMA type 1 and severe spinal deformity, who received nusinersen via a subcutaneously implanted Ommaya reservoir connected with an intrathecal catheter at the thoracic level. The repetitive administrations were completed uneventfully, obviating the need for repeated laborious lumbar punctures and eliminating radiation exposure. In adult SMA patients, performing recurrent lumbar punctures can be technically challenging raising the need for an alternative route of administration. The use of Ommaya reservoirs is a viable, practical for repeated infusions, and safe option for the intrathecal delivery of nusinersen for select cases such as an adult SMA type 1 survivor with severe spinal deformity.

A Systematic Review of Procedural Complications from Transforaminal Lumbar Puncture for Intrathecal Nusinersen Administration in Patients with Spinal Muscular Atrophy

BACKGROUND

Spinal muscular atrophy is a progressive neurodegenerative disorder that can be treated with intrathecal antisense oligonucleotide therapy (nusinersen). However, administration is often complicated by posterior spinal fusion and neuromuscular scoliosis, necessitating a transforaminal approach.

PURPOSE

To assess the safety profile of the transforaminal approach for intrathecal access.

DATA SOURCES

Searches of the PubMed, Web of Science, and SCOPUS databases.

STUDY SELECTION

Thirteen articles were selected based on inclusion of transforaminal access and appropriate clinical information about the procedure.

DATA ANALYSIS

Complications were taken from the included articles and aggregated based on Cardiovascular and Interventional Radiological Society of Europe scale adverse event grading.

DATA SYNTHESIS

Total number of complications and grade of complications were analyzed, by year and in total.

LIMITATIONS

Selection bias in publication, small patient population size, and variability of the procedure limits the available data.

CONCLUSIONS

Transforaminal approach is a safe alternative for intrathecal access in patients with spinal muscular atrophy and may be applicable to a larger patient population.

Pediatric SMA patients with complex spinal anatomy: Implementation and evaluation of a decision-tree algorithm for administration of nusinersen

The approval of nusinersen for the treatment of spinal muscular atrophy (SMA) has significantly changed the natural history of the disease. Nevertheless, scoliosis secondary to axial muscle weakness occurs at some point in most of patients with SMA and a conventional posterior interlaminar approach for intrathecal administration of nusinersen can be particularly challenging to perform in patients with severe scoliosis and/or previous spine fusion surgeries. We developed a protocol for the administration of nusinersen in pediatric patients, which includes a decision-tree algorithm that categorizes patients according to the estimated technical difficulty for the intrathecal administration. Complex spine patients were defined as those with a Cobb angle greater than 50° and/or a history of spinal surgery, while the rest of patients were considered non-complex. Nusinersen was successfully administered through a conventional non-CT-guided lumbar puncture in all 14 non-complex spine patients (110 out of 110 procedures; 100%). The feasibility of the intrathecal injection in the 15 complex spine patients was assessed by 3D CT. Administration was considered unfeasible in 7 out of these 15 patients according to imaging. In the 8 complex spine patients in whom the administration was considered feasible, conventional non-CT-guided lumbar punctures were successful only in 19 out of 53 procedures (36%). The remaining 34 procedures (64%) were guided by CT scan, all successful. Our work demonstrates that a cut-off point of 50° in Cobb angle and history of spinal surgery can reliably be used to anticipate the need for CT guidance in nusinersen administration.

Posterior Spinal Correction and Fusion Surgery in Patients with Spinal Muscular Atrophy-Associated Scoliosis for Whom Treatment with Nusinersen Was Planned

INTRODUCTION

Spinal muscular atrophy (SMA) is defined as a neuromuscular disorder induced by progressive weakness of the skeletal muscle and is usually accompanied by progressive spinal deformity including scoliosis. The newly developed Nusinersen, which is the first approved drug worldwide for SMA, requires accurate intrathecal injection, which is sometimes difficult in patients with severe spinal deformity.

TECHNICAL NOTE

For an accurate intrathecal approach in patients who have spinal fusion surgery to treat neuromuscular scoliosis, we have combined an L3 laminectomy with spinal correction and fusion surgery. Here, we review four cases of SMA in patients who underwent the additional L3 laminectomy during surgery to treat spinal scoliosis. A successful intrathecal approach was made using fluoroscopic guidance in all four patients, who were then administered with Nusinersen.

CONCLUSIONS

Our findings show that additional lumbar laminectomy during surgery for spinal scoliosis has effectively allowed for intrathecal injection of Nusinersen.