Spinal Cord Stimulation (SCS) has emerged as one of the most impactful interventions for refractory chronic pain, with over 50,000 implants performed annually in the United States. Literature spanning two decades confirms its safety and efficacy^[1,2] — yet the procedure carries an overall complication rate of 30–40%, with hardware-related failures, lead migration, and biological complications all documented.^[2,6,7]

The most common hardware complication is lead migration, with rates documented from 13.2% in Cameron's landmark 20-year review^[1] to 20–22.6% in more recent series.^[6,7] The most common neurological complication is inadvertent dural puncture — occurring in 0.81% of lead insertions and resulting in postdural puncture headache in every affected case.^[3]

What links these complications? In most cases: the irreducible limitation of fluoroscopy. The standard imaging method for SCS placement reveals bones precisely and soft tissue not at all.^[5] Every judgment about dural proximity, epidural fibrosis, and electrode-to-cord distance is an educated estimate — and that estimation gap is where lead malpositioning, dural puncture, and suboptimal stimulation coverage originate.

VerAvanti's Scanning Fiber Endoscope (SFE) addresses this gap directly. By adding direct, real-time optical coherence tomography (OCT) imaging to the epidural approach, the SFE transforms SCS lead placement from a fluoroscopy-dependent inference exercise into a precision-guided procedure where tissue anatomy is visible, dural proximity is measured, and lead positioning is confirmed — not assumed.

1. The Visibility Gap: Fluoroscopy vs. SFE

To understand the SFE value proposition in SCS placement, it is useful to map exactly what each imaging modality sees at each critical step of the procedure. A 2022 survey of SCS practitioners documented wide variability in fluoroscopic technique — lateral views always used by 45.6%, contralateral oblique views always used by only 14.8% — reflecting an ongoing consensus gap about optimal depth visualization even within fluoroscopy's native domain.^[5]

Figure 1: Direct comparison of fluoroscopy and SFE visualization capability across six critical placement variables

The gap is not subtle. Every soft-tissue variable that determines clinical success — dural proximity, epidural space integrity, fibrosis, electrode-to-cord distance — is invisible to fluoroscopy and directly addressable by OCT-based imaging.^[10,11] Fluoroscopy remains essential for confirming vertebral level and monitoring lead advancement trajectory. The SFE adds the missing dimension.

It is important to note that fluoroscopy itself does not eliminate dural puncture risk. Simopoulos et al. reported a dural puncture rate of 0.81% per lead insertion despite universal fluoroscopic use, with all affected patients developing postdural puncture headache.^[3] Risk factors compound this: prior surgery at the needle entry site, obesity, spinal stenosis, and scoliosis each independently increase dural puncture risk^[4,6] — precisely the patient population most likely to present for SCS therapy.

2. The Scientific Basis: OCT Imaging in the Spinal Epidural Space

The use of optical coherence tomography for epidural guidance is not speculative — it is an active and well-documented area of preclinical and translational research with results directly applicable to SCS lead placement.

Figure 2: SFE optical fiber co-deployed with SCS lead — OCT scan beams interrogate the dural interface in real time with ~3 mm depth penetration

OCT Visualization of the Epidural Space

Lee et al. (2017) were among the first to demonstrate in vivo OCT imaging of the epidural space in a porcine model, successfully visualizing the epidural space in 2D and 3D, tracing epidural catheter position in real time, and imaging the dural puncture process — all delivered via a standard 18-gauge Tuohy needle.^[10] The authors concluded that OCT provides a novel, minimally invasive means of observing the spinal epidural space with clinically actionable anatomic detail.

Tang et al. (2015) developed a forward-imaging OCT needle device and validated its ability to distinguish epidural space, ligamentum flavum, and spinal cord in both ex vivo and in vivo animal experiments.^[11] Their system achieved real-time tissue layer identification with sufficient contrast to support epidural space confirmation — a capability directly applicable to SCS lead placement guidance.

Wang et al. (2022) advanced this further by combining forward-view endoscopic OCT with deep learning classifiers, achieving over 99% precision in detecting the transition from ligamentum flavum to epidural space.^[12] The same group later demonstrated that polarization-sensitive OCT can additionally differentiate nerve fibers through birefringence contrast^[13] — a capability that could, in the SCS context, distinguish dorsal column tissue from dorsal root tissue in real time.

OCT for Spinal Cord and Intrathecal Imaging

Roy et al. (2021) demonstrated minimally invasive intrathecal OCT imaging in a porcine model, successfully visualizing the dural lining, epidural veins, pial lining of the spinal cord, arachnoid bands, dentate ligaments, and nerve rootlets — all via a catheter introduced through a Tuohy needle.^[14] The authors explicitly noted that a spine-specific device is necessary for clinical translation, and that the optimal system would have a small enough diameter and depth of tissue penetration matched to the epidural space — parameters the SFE satisfies.

Cavaglia et al. (2016) demonstrated that OCT can provide real-time imaging of spinal cord microstructure during probe placement in a rat model, confirming that OCT irradiation produces no detectable electrophysiological interference with spinal neuronal activity.^[15] This safety confirmation is directly relevant to the SFE application: an OCT fiber co-deployed with an SCS lead does not compromise the neurophysiological measurements that drive awake paresthesia mapping.

3. The Five Placement Pillars — SFE at Every Stage

Successful SCS implantation depends on five critical variables. The SFE adds measurable value at each one, with greatest impact at the depth and stability pillars where fluoroscopy is most limited.

Figure 3: SFE value mapped to each of the five SCS placement pillars — from level confirmation through post-anchoring verification

The depth pillar represents the highest-value SFE contribution. As Southerland et al. (2022) documented, dural puncture is the most common neurological complication of SCS^[4] — and the risk factors that predispose to it (obesity, prior surgery, stenosis) describe a large portion of the SCS candidate population. The SFE transforms this risk from a statistical inevitability to a measurable, real-time variable: the physician sees the remaining distance to the dura rather than estimating it.

The fluoroscopic limitations documented in the SCS literature also directly impair the laterality pillar. Gill et al. (2022) noted that fluoroscopy's inability to clearly define the posterior margin of the epidural space is particularly problematic at cervical and upper thoracic levels^[5] — precisely where the margin for error is smallest and where the SFE's sub-millimeter resolution most directly compensates.

4. Three Clinical Scenarios Where SFE is Transformative

Figure 4: High-value clinical scenarios — post-laminectomy syndrome, cervical SCS, and closed-loop SCS — where SFE visualization is most critical

4.1 Post-Laminectomy Syndrome (Failed Back Surgery Syndrome)

This is simultaneously the most common SCS indication and the hardest population to implant. Prior laminectomy creates epidural fibrosis — bands of scar tissue that can occlude the epidural space, adhere the dura to the lamina, and redirect the lead away from the midline.

The 2024 case series by Oluwadamilola et al. documented intrathecal lead malpositioning in patients undergoing percutaneous SCS, noting explicitly that "a high BMI can predispose to malpositioning by imaging constraints, reducing visualization under fluoroscopy" and that canal stenosis, loss of epidural fat, and spondylosis were complicating factors that fluoroscopy failed to adequately characterize.^[8] Both cases required surgical revision to paddle electrodes after the intrathecal malpositioning was identified postoperatively.

Under fluoroscopy, the physician knows only that lead advancement has become more resistant. The SFE shows why — whether fibrosis is present, its density, its location in the epidural corridor, and whether advancing further risks dural tenting. The preclinical literature confirms that OCT can differentiate fibrotic tissue from normal epidural fat with distinct morphological features.^[10]

4.2 Cervical SCS Placement (C3–C7)

Cervical SCS is growing in adoption for upper extremity pain, CRPS, and cervicogenic conditions — but the cervical epidural space is only 2–3 mm wide versus 5–6 mm in the lumbar region. Gill et al. (2022) specifically identified this as a domain where fluoroscopic limitations are most consequential: "the CLO view is especially useful in upper thoracic and cervical access where the interlaminar window is narrow, the margin of error very low, and the lateral view is particularly suboptimal."^[5]

The same survey found that cervical/upper thoracic access approach patterns were highly variable across practitioners — 43.3% used cervicothoracic access, while the rest used lower thoracic approaches — reflecting the procedural uncertainty that currently characterizes this indication.^[5] Simopoulos et al. (2016) reported that the cervicothoracic region (C7–T5) had a dural puncture rate of 1.1% per lead — nearly double the thoracolumbar rate.^[3]

4.3 Closed-Loop SCS — Optimal Baseline Calibration

Closed-loop SCS systems that measure evoked compound action potentials (ECAPs) and adjust stimulation amplitude in real time represent the fastest-growing segment of the neuromodulation market. Their efficacy advantage over open-loop systems depends on accurate initial calibration — which depends on exact lead-to-cord geometry at the time of implant.

The OCT literature directly supports this application: Wang et al. (2022) demonstrated that OCT-based tissue classification can predict the distance from the needle tip to the dura with over 90% overall accuracy,^[12] and Tang et al. (2015) showed that dura identification is achievable with high specificity in real-time forward-imaging OCT systems.^[11] Together, these capabilities support confirmed lead-to-dura gap measurement before ECAP baseline is set — enabling anatomy-confirmed closed-loop calibration rather than probabilistic positioning.

5. Anatomic and Procedural Reference

The following diagrams provide clinical reference material on SCS placement anatomy and technique, establishing the anatomic context within which SFE imaging is applied.

Spinal Anatomy — The Epidural Target

Figure 5: Spinal cord cross-section (axial view) — the SCS lead occupies the posterior epidural space bounded by lamina posteriorly and dura anteriorly

The posterior epidural space — 2–3 mm cervically to 5–6 mm lumbar — is the SCS implant zone. OCT imaging at 15–25 µm axial resolution resolves all relevant tissue layers: epidural fat, venous plexus, dura mater (250–400 µm thick), and the outer CSF layer.^[11,14]

6. VerAvanti's Strategic Position

The neuromodulation market has spent the past decade advancing stimulation technology — paresthesia-free waveforms, closed-loop systems, DRG stimulation. The guidance infrastructure has not kept pace. Fluoroscopy remains the only intraoperative imaging standard for a procedure whose most consequential variables are invisible to it.

The research foundation exists. Multiple independent groups have demonstrated that OCT-based epidural imaging through Tuohy-needle-compatible probes is feasible, provides clinically actionable tissue contrast, and does not interfere with spinal neurophysiology.^{[10,11,12,13,14,15]} VerAvanti's SFE platform is the clinical translation of this body of evidence: a single scanning fiber architecture miniaturized for epidural delivery, validated across intravascular and endoluminal applications, and positioned for 510(k) clearance in 2026.

Conclusion

The complication data are clear: 30–40% of SCS patients experience at least one adverse event,^[2,6] lead migration rates range from 13% to 23%,^[1,6,7] and dural puncture occurs in nearly 1 in 100 lead insertions despite universal fluoroscopic use.^[3] These are not failures of surgical technique — they are the predictable consequences of performing a precision procedure without adequate soft-tissue visualization.

The OCT literature demonstrates that the visualization gap is closable. Epidural space anatomy is distinguishable by OCT through Tuohy-needle-compatible probes;^[10,11] dura-to-tip distance is measurable in real time;^[12] and spinal cord OCT imaging produces no detectable neurophysiological interference.^[15] VerAvanti's SFE platform brings these capabilities to SCS lead placement — not as a future aspiration, but as a device in active development targeting FDA 510(k) clearance in 2026.

For the post-laminectomy patient with a scarred epidural space.^[8] For the cervical SCS candidate where fluoroscopy's limitations are greatest.^[5] For the closed-loop SCS patient whose long-term outcomes depend on a calibration performed accurately on day one. The SFE delivers the information those procedures have always needed.

VerAvanti is pursuing FDA 510(k) clearance in 2026 with First-in-Human targeted for Q4 2027. For research collaboration, KOL engagement, or clinical partnership inquiries, contact VerAvanti Corporation, Bothell, WA.

References

SCS Complications and Fluoroscopy Limitations

[1]  Cameron T. Safety and efficacy of spinal cord stimulation for the treatment of chronic pain: a 20-year literature review. J Neurosurg. 2004;100(3 Suppl Spine):254-267. PMID: 15070488.

[2]  Eldabe S, Buchser E, Duarte RV. Complications of spinal cord stimulation and peripheral nerve stimulation techniques: a review of the literature. Pain Med. 2016;17(2):325-336. PMID: 26814260.

[3]  Simopoulos TT, Sharma S, Aner M, Gill JS. The incidence and management of postdural puncture headache in patients undergoing percutaneous lead placement for spinal cord stimulation. Neuromodulation. 2016;19(7):738-743. PMID: 27172329.

[4]  Southerland WA, Hasoon J, Urits I, Viswanath O, Simopoulos TT, et al. Dural puncture during spinal cord stimulator lead insertion: analysis of practice patterns. Anesth Pain Med. 2022;12(2):e127179. PMC9364517.

[5]  Gill J, Kohan L, Hasoon J, et al. Contralateral and lateral views: analysis of the technical aspects of spinal cord stimulator lead insertion. Anesth Pain Med. 2022;12(2). PMC8995871.

[6]  Vu PD, Pinkhasova D, Sarwary ZB, et al. Biologic complications associated with cylindrical lead spinal cord stimulator implants: a narrative review. Orthopedic Reviews. 2024;16. PMID: 39624470.

[7]  Blackburn AZ, Chang HH, DiSilvestro K, et al. Spinal cord stimulation via percutaneous and open implantation: systematic review and meta-analysis examining complication rates. World Neurosurgery. 2021;154. doi:10.1016/j.wneu.2021.07.077.

[8]  Oluwadamilola OD, Ludewig PM, Morici JA, Ahammad Z. Intrathecal placement of percutaneous spinal cord stimulation leads: illustrative cases. J Neurosurg Case Lessons. 2024;8(13):CASE24275. PMID: 39312805.

[9]  Walton E, Zhitny VP, Dixon B, Jannoud R, Rahman I. Migration of epidural leads during spinal cord stimulator trials. Ann Med Surg (Lond). 2025. PMC9518680.

OCT Epidural and Spinal Imaging Research

[10]  Lee SH, Cabrales J, Grochowski CM, et al. In vivo images of the epidural space with two- and three-dimensional optical coherence tomography in a porcine model. PLoS ONE. 2017;12(2):e0172149. PMC5308840.

[11]  Tang Q, Singh M, Li R, et al. Real-time epidural anesthesia guidance using optical coherence tomography needle probe. Quant Imaging Med Surg. 2015;5(1):118-124. PMID: 25694961.

[12]  Wang C, Calle P, Reynolds JC, et al. Epidural anesthesia needle guidance by forward-view endoscopic optical coherence tomography and deep learning. Sci Rep. 2022;12:9057. doi:10.1038/s41598-022-12950-7.

[13]  Wang C, Calle P, Tran Ton NB, et al. Enhancing epidural needle guidance using a polarization-sensitive optical coherence tomography probe with convolutional neural networks. J Biophotonics. 2024;17:e202300330. PMC10922538.

[14]  Roy AK, Sloan AE, Janaki MR, et al. Minimally invasive intrathecal spinal cord imaging with optical coherence tomography. Neurosurgery. 2021;89(1):73-80. PMID: 33988003.

[15]  Cavaglia M, Trignano C, De Riu P, et al. Electrophysiological and anatomical correlates of spinal cord optical coherence tomography. PLoS ONE. 2016;11(4):e0152539. doi:10.1371/journal.pone.0152539.