The Complex Spine in Children with Spinal Muscular Atrophy: The Transforaminal Approach-A Transformative Technique

Needleless inhaled anesthesia with sevoflurane: Advantages of a simplified approach for children with spinal muscular atrophy undergoing intrathecal administration of nusinersen

BACKGROUND

Intrathecal nusinersen administration, a fundamental step in the treatment of spinal muscular atrophy, is challenging in children.

AIMS

This retrospective monocentric analysis of prospectively collected data evaluated the feasibility of needleless general anesthesia exclusively with sevoflurane, without imaging guidance, for children undergoing nusinersen administration in a 24-month period.

METHODS

Clinical data included demographics, type of spinal muscular atrophy, presence and severity of scoliosis. Primary outcome was defined by the number of predefined sentinel adverse events related to anesthesia. Secondary outcomes were assessed by duration of the procedure, number of lumbar puncture attempts, and number of failures. Other measures included number and type of moderate, minor and minimal adverse events, as well as number and type of puncture-related adverse events.

RESULTS

116 patients (mean age: 8.7 (SD 6.9) years; with scoliosis: 49.1%) underwent 250 lumbar punctures; two cases of prolonged desaturation, considered as sentinel adverse events, (0.8%) were recorded during anesthesia (primary outcome). None of the patients underwent orotracheal intubation nor required an unplanned admission in the Pediatric Intensive Care Unit. No patient required an unplanned or prolonged hospitalization after the procedure. Mean number of puncture attempts was 1.6 (SD 1.3), and mean duration of the procedure was 14.1 (SD 8.3) minutes. No failure in the drug administration occurred (secondary outcomes).

CONCLUSION

In this single-center experience, needleless general anesthesia with inhaled sevoflurane without imaging guidance has been shown to be feasible for children with spinal muscular atrophy undergoing lumbar puncture for nusinersen administration.

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.

Nusinersen for Patients With Spinal Muscular Atrophy: 1415 Doses via an Interdisciplinary Institutional Approach

BACKGROUND

Spinal deformity and prior spinal fusion pose technical challenges to lumbar puncture (LP) for nusinersen administration for patients with spinal muscular atrophy (SMA). In this retrospective study over two study phases, we evaluated (1) factors associated with difficult LP or unscheduled requirement for image guidance and (2) effectiveness of a triage pathway for selective use of image guidance and nonstandard techniques, particularly for patients with spinal instrumentation/fusion to the sacrum.

METHODS

With institutional review board approval, electronic health records, imaging, and administrative databases were analyzed for patients receiving nusinersen from January 2012 through September 2021. Descriptive statistics and univariate analyses were used.

RESULTS

From January 2012 to March 2018 (phase 1), among 82 patients with SMA, 461 of 464 (99.4%) LP attempts were successful. Univariate analyses associated difficulty with prior spinal instrumentation, higher body mass index, and severity of the spinal deformity. Based on this experience, starting in April 2018 (phase 2), 125 patients were triaged selectively for ultrasound, fluoroscopy, or Dyna computed tomography. Patients with spinal instrumentation/fusion to the sacrum were treated primarily via intrathecal ports (137 doses) or transforaminal LP (55 doses). From April 2018 through September 2021, 704 of 709 (99.3%) LPs were successful. In total from January 2012 to September 2021, 1415 doses were administered. Over 50% of LPs were performed by neurology nurse practitioners without image guidance. Safety outcomes were excellent.

CONCLUSIONS

A stratified approach resulted in successful intrathecal nusinersen delivery and efficient resource allocation for patients with SMA, with or without complex spinal anatomy.

Transforaminal lumbar puncture for spinal anesthesia or novel drug administration: a technique combining C-arm fluoroscopy and ultrasound

Background

Lumbar puncture (LP) may be challenging for patients with scoliosis and other conditions following previous posterior fusion and instrumentation from thoracic to sacral levels. Interventional radiologists have described CT approaches to transforaminal LP. We hypothesized that combined C-arm fluoroscopy and ultrasound could be a feasible approach to transforaminal LP for interventional pain physicians and regional anesthesiologists.

Methods

With institutional review board approval, we reviewed medical records and imaging of six patients with spinal muscular atrophy and prior spine fusion. Non-cutting needles of 24 or 25 gage were advanced through 20-gage introducers. Prior imaging guided selection of a preferred side and spinal level. Initial procedures were performed in the interventional radiology suite. Subsequent procedures were performed in an operating room (OR). We report on technical success and complications and describe a case using this approach for spinal anesthesia.

Results

Six patients underwent a total of 54 transforaminal LPs, including 51 for administration of the antisense oligonucleotide nusinersen, 2 for myelography, and 1 for spinal anesthesia; 45 of these procedures were performed using OR C-arm fluoroscopy and ultrasound. Transient paresthesias and short-term headaches occurred; none required intervention. No other complications were noted.

Conclusions

Transforaminal LP appears technically feasible for patients with full-spine fusions using a straight-needle approach with combined fluoroscopy and ultrasound guidance. Larger case series and prospective studies may better define the success rates, risks, and benefits of this approach relative to alternative approaches to intrathecal access for patients with previous long-segment posterior spine fusions.

Intrathecal catheter and port placement for nusinersen infusion in children with spinal muscular atrophy and spinal fusion

BACKGROUND

Spinal administration of medications is challenging in patients with complete posterior spinal fusion. We describe percutaneous image-guided intrathecal port placement for administration of the antisense oligonucleotide nusinersen for children and young adults with spinal muscular atrophy.

OBJECTIVE

To describe and present our initial experience with a new technique for administering nusinersen in patients with spinal muscular atrophy and posterior spinal fusion.

MATERIALS AND METHODS

We reviewed medical records of 13 patients who received intrathecal ports using DynaCT, biplane fluoroscopy and iGuide from April 2018 through June 2019, and we describe the clinical course over 1 year.

RESULTS

Image-guided catheter and port implantation was successful in all cases. Two ports were subsequently removed, one for persistent cerebrospinal fluid leak and one for superficial infection. The other 11 have functioned successfully for a minimum of 23 months.

CONCLUSION

We report our experience with image-guided intrathecal port placement in children with complete posterior spine fusion. The implanted port permits dosing in an outpatient setting and avoids the need for multiple future radiologic procedures, and it reduces discomfort, procedural costs and potential risks and sequelae of multiple anesthetics and radiation exposures. Further studies are needed to define the relative risks and benefits of intrathecal ports compared to other approaches such as repeated transforaminal lumbar punctures.

Nusinersen by subcutaneous intrathecal catheter for symptomatic spinal muscular atrophy patients with complex spine anatomy

INTRODUCTION/AIMS

Intrathecal administration of nusinersen is challenging in patients with spinal muscular atrophy (SMA) who have spine deformities or fusions. We prospectively studied the safety and efficacy of nusinersen administration via an indwelling subcutaneous intrathecal catheter (SIC) for SMA patients with advanced disease.

METHODS

Seventeen participants commenced nusinersen therapy between 2.7 and 31.5 years of age and received 9 to 12 doses via SIC. Safety was assessed in all participants. A separate efficacy analysis comprised 11 nonambulatory, treatment-naive SMA patients (18.1 ± 6.8 years) with three SMN2 copies and complex spine anatomy.

RESULTS

In the safety analysis, 14 treatment-related adverse events (AEs) occurred among 12 (71%) participants; all were related to the SIC and not nusinersen. Device-related AEs interfered with 2.5% of nusinersen doses. Four SICs (24%) required surgical revision due to mechanical malfunction with or without cerebrospinal fluid leak (n = 2), and one (6%) was removed due to Staphylococcus epidermidis meningitis. In the efficacy analysis, mean performance on the nine-hole peg test improved in dominant (15.9%, P = 0.012) and nondominant (19.0%, P = 0.008) hands and grip strength increased by 44.9% (P = 0.031). We observed no significant changes in motor scales, muscle force, pulmonary function, or SMA biomarkers. All participants in the efficacy cohort reported one or more subjective improvement(s) in endurance, purposeful hand use, arm strength, head control, and/or speech.

DISCUSSION

For SMA patients with complex spine anatomy, the SIC allows for reliable outpatient administration of nusinersen that results in meaningful improvements in upper limb function, but introduces risks of technical malfunction and iatrogenic infection.

Computed tomography-guided transforaminal lumbar puncture using local anesthesia and a straight 22-gauge spinal needle for intrathecal nusinersen in adults: Findings in 77 procedures

BACKGROUND

Intrathecal nusinersen is the first Food and Drug Administration-approved treatment for spinal muscular atrophy. Reliable intrathecal access is critical for initial and maintenance therapy; however, this can be challenging in older patients with spinal muscular atrophy many of whom have had prior lumbar instrumentation and osseous fusion. Transforaminal lumbar punctures have emerged as a technique for intrathecal access that avoids the hazards of cervical punctures. We describe our technique for transforaminal lumbar punctures under computed tomography guidance using local anesthesia and a straight 22-gauge needle.

METHODS

Following local institutional review board approval, medical records of all patients undergoing computed tomography-guided transforaminal lumbar puncture for intrathecal nusinersen injection were obtained and analyzed. The rate of technical success and immediate complications were recorded. Any delayed complications noted in a 3-day follow-up phone call and future office visit were also recorded. Data collation and analysis were performed using Excel.

RESULTS

A total of 77 transforaminal lumbar punctures were performed with intrathecal administration of nusinersen, for a 100% technical success rate. Local anesthesia was used in 76 cases, with conscious sedation used in one case. General anesthesia was not used in any case. There were no major complications. One patient had a postdural puncture headache that resolved completely after a transforaminal epidural blood patch performed 4 days later.

CONCLUSIONS

Intrathecal administration of nusinersen is critical for treatment of patients with spinal muscular atrophy. Our described technique allows for reliable access to the intrathecal space using local anesthesia and a straight 22-gauge spinal needle under computed tomography guidance, and is easily reproducible.

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.

Imaging anatomy of the vertebral canal for trans-sacral hiatus puncture of the lumbar cistern

A standard lumbar puncture may be impossible for many anatomic or technical reasons. Previous accounts of caudal epidural anesthesia and other procedures via the sacral hiatus prompted us to test if image-guided percutaneous trans-sacral hiatus access to the lumbosacral subarachnoid cistern would be anatomically feasible. To study vertebral canal morphometry and curvature, we analyzed midsagittal computed tomography-myelogram images of 40 normal subjects and digitally measured sacral curvatures between S1 to S5 and S2 to S4 using two methods whereby a lower angle signifies a straighter sacrum. We measured midsagittal vertebral canal area, hiatus width, dural sac termination levels, and distance from sacral hiatus to the dural sac tip (needle distance). Subjects were F:M = 25:15, with a mean age of 44.9 years. The two S1-S5 full sacral curvature mean angles were 57.3° and 60.4°. Almost all sacral hiatuses were at S4, and dural sac terminations were at S1-S2. The mean S2-S4 sacral curvature was 25.1°, and the mean needle distance was 57.7 mm. Using two-way analysis of variance, there were significant sex differences for needle distances (p = .001), and full and limited sacral curvatures (p = .02, and p = .046, respectively). There were no significant linear regression correlations between age and sacral curvature, needle distance, canal area, or hiatus width. Therefore, despite a frequently prominent full sacral curvature, the combination of S1-S2 dural sac termination plus a relatively straight trajectory of the lower vertebral canal between S2 and S4 support the theoretical feasibility of percutaneous trans-sacral hiatus and vertebral canal access to the lumbosacral cistern using a standard spinal needle.

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

BACKGROUND AND PURPOSE

The purpose was to investigate our centre's experience on computed-tomography-guided (CT-guided), transforaminal, intrathecal administration of nusinersen in adult subjects with spinal muscular atrophy (SMA) type 2 and severe spinal deformity.

METHOD

This is a retrospective, single-centre study investigating the feasibility and safety of CT-guided, transforaminal, lumbar puncture for the intrathecal administration of nusinersen (Spinranza®; Biogen; Cambridge, MA, USA) in a cohort of adult subjects with SMA type 2, severe neuromuscular scoliosis and previous spinal surgery. Between January 2019 and October 2019, five male, adult, SMA type 2 subjects were eligible to be treated in our centre with nusinersen. The mean age of the patients was 31 ± 9 years (range 19-43 years). The study's outcome measures were technical success, adverse events and radiation exposure.

RESULTS

In total, four patients completed the four loading doses, whilst the fifth patient received only one loading dose; two patients also received their first maintenance doses. Overall, 20 consecutive transforaminal, intrathecal treatments were analysed. Technical success was 100% (20/20 intrathecal infusions). No adverse events were documented following the procedures. Mean dose-length product (DLP) value per injection was 665.4 ± 715.5 mGy*cm. Estimated mean effective dose per injection was 12.7 ± 12.9 mSv. Subgroup analysis between the chronologically first 10 versus subsequent 10 procedures demonstrated a clear trend towards less radiation exposure in the latter, although this difference did not reach statistical significance (DLP: 984.7 ± 903.3 vs. 436.7 ± 321.5 mGy*cm, P = 0.165; respectively).

CONCLUSIONS

In this retrospective series, CT-guided transforaminal access for intrathecal injection of nusinersen was proven feasible and safe. A decrease in radiation dose over time was noted. Protocols to minimize radiation exposure are essential.

Transforaminal intrathecal delivery of nusinersen for older children and adults with spinal muscular atrophy and complex spinal anatomy: an analysis of 200 consecutive injections

BACKGROUND

Nusinersen is the only approved treatment for all spinal muscular atrophy (SMA) subtypes and is delivered intrathecally. Distorted spinal anatomy and instrumentation preclude standard approaches for intrathecal access, necessitating alternative techniques for delivery. The purpose of this study is to report technical success and adverse events of transforaminal intrathecal delivery of nusinersen.

METHODS

28 patients, mean age 24.1±9.8 years (range 10.0-51.0 years), with intermediate or late onset SMA, underwent a combined 200 transforaminal nusinersen injections. All patients had osseous fusion or spinal instrumentation precluding standard posterior access routes. Patients who underwent nusinersen injections using a technique other than transforaminal lumbar puncture (n=113) were excluded. Technical success, adverse events (AEs) and radiation exposure were recorded.

RESULTS

200 (100%) procedures were technically successful; 6 (3%) required a second level of attempt for access. 187 (93.5%) interventions were completed using cone beam computed tomography (CBCT) with two-axis fluoroscopic navigational overlay. 13 (6.5%) procedures were performed with fluoroscopic-guidance only at subsequent sessions. There were 8 (4.0%) mild AEs and 2 (0.5%) severe AEs; one patient received antibiotics for possible traversal of the large bowel but did not develop meningitis, and one patient developed aseptic meningitis. Mean air kerma was 74.5±161.3 mGy (range 5.2-1693.0 mGy).

CONCLUSION

Transforaminal intrathecal delivery of nusinersen is feasible and safe for gaining access in patients with distorted spinal anatomy. The use of CBCT delineates anatomy and optimizes needle trajectory during the initial encounter, and may be used selectively for subsequent procedures.

Intrathecal delivery of nusinersen in individuals with complicated spines

BACKGROUND

The treatment of spinal muscular atrophy (SMA) with nusinersen requires intrathecal medication administration, which can be challenging in individuals with complicated spines. This retrospective case series reviews the nusinersen treatment experience at one academic medical center with children and adults with SMA and complicated spines.

METHODS

Twenty medical records of individuals receiving nusinersen were reviewed and administration methods summarized and assessed.

RESULTS

Ten children and 10 adults were treated, and 55% had complicated spines. In total, 163 treatments were given, 91 in those with complicated spines. In the complicated spines, 74% of treatments were done by means of fluoroscopic lumbar puncture, 22% by means of intrathecal Ommaya reservoir, 3% by means of palpation, and < 1% by means of computed tomography-guided transforaminal approach.

CONCLUSIONS

A large majority of individuals with complicated spines can receive intrathecal nusinersen using fluoroscopic guidance in the lumbar region. Other delivery methods are available but less frequently used.

Transforaminal lumbar puncture for intrathecal access: Case series with literature review and comparison to other techniques

Fluoroscopic-guided lumbar puncture (LP) is a procedure commonly performed by radiologists, which in some circumstances may be difficult or impossible using a traditional posterior interspinous or interlaminar approach. Alternatives to LP include cervical and cisternal punctures, placement of an Ommaya reservoir, and lumbar laminectomy. More recently, however, there has been a move toward access of the thecal sac through a transforaminal approach in patients with challenging anatomy. This report outlines our approach and experience using transforaminal LP (TFLP) in patients with spinal muscular atrophy (SMA) with a 100% success rate. We discuss its utility in other patients with difficult access and compare TFLP with other techniques to access the intrathecal space.