Case Prep: Syringomyelia — Management / Syringosubarachnoid Shunt

Case / Approach Snapshot

• Anatomy at risk: the named neural, vascular, bony, CSF, and soft-tissue structures that determine the safe corridor and likely morbidity.
• Operative steps: confirm indication and imaging, position and expose deliberately, complete the core surgical maneuver, verify the result, and close with a complication-prevention plan; use the detailed operative sequence and approach notes below as the step-by-step source.
• Rescue plans: bleeding, neurologic change, wrong target or level, CSF leak, infection, hardware or reconstruction failure, and a staged or alternate-treatment plan.
• Figures: review Figures, Imaging & Video and the Curated Image Set; embedded local figures should remain open-access, public-domain, or otherwise reusable with attribution.
• Papers: review High-Yield Literature for seminal sources, modern reviews, and outcome data specific to this page.

One-Liner

[Age]yo [M/F] with [Chiari-associated / post-traumatic / idiopathic] syringomyelia at [levels] presenting with [dissociated sensory loss / hand weakness / pain / progressive myelopathy] planned for [treatment of underlying cause / syringosubarachnoid shunt].

Figures, Imaging & Video

🎥 Operative video — search operative video on YouTube ▸ · The Neurosurgical Atlas ▸

🧭 Operative approach: Posterior cervical approach or posterior thoracolumbar approach — choose by syrinx driver and exposure level.

Neurosurgical Atlas · Radiopaedia · PubMed Central — operative figures © linked; see media-sources.md

High-Yield Literature

• Syringosubarachnoid shunt: insertion technique — Amarouche M. British journal of neurosurgery 2023. PubMed
• Ultrasound-guided Syringosubarachnoid Shunt Insertion for Cervicothoracic Syringomyelia — Hussain I. Clinical spine surgery 2020. PubMed
• Syringosubarachnoid shunt for treatment of syringomyelia — Vaquero J. Acta neurochirurgica 1987. PubMed
• Treatment of syringomyelia with a syringosubarachnoid shunt — Tator CH. The Canadian journal of neurological sciences. Le journal canadien des sciences neurologiques 1988. PubMed
• Reevaluation of syringosubarachnoid shunt for syringomyelia with Chiari malformation — Iwasaki Y. Neurosurgery 2000. PubMed
• Syrinx shunts for syringomyelia: a systematic review and meta-analysis of syringosubarachnoid, syringoperitoneal, and syringopleural shunting — Rothrock RJ. Journal of neurosurgery. Spine 2021. PubMed
• [Syringosubarachnoid shunt for noncommunicating syringomyelia associated with spinal lipoma: a case report] — Yamamuro S. No shinkei geka. Neurological surgery 2012. PubMed
• Syringosubarachnoid shunt for syringomyelia associated with Chiari I malformation — Hida K. Neurosurgical focus 2001. PubMed
• Polytetrafluoroethylene sponge syringosubarachnoid shunt — Chagla AS. Turkish neurosurgery 2011. PubMed
• Minimally invasive insertion of syringosubarachnoid shunt for posttraumatic syringomyelia: technical case report — O’Toole JE. Neurosurgery 2007. PubMed

Curated Image Set

Open-access figures are embedded from PubMed Central articles and kept unique to this guide.

Figure 1:. Preoperative radiological findings. (a) A sagittal view of a plain computed tomography scan demonstrates a burst fracture of the L2 vertebra (arrow). Note that the L2 vertebra is… Source: Cauda equina syndrome due to posttraumatic syringomyelia in conus medullaris – A case report — Surgical Neurology International 2024; CC BY-NC-SA.

Figure 2:. Intraoperative findings. (a) Following the dural opening, the conus medullaris and cauda equina protruded from the dural sac. Note no adhesive arachnoiditis. (b) The conus medullaris was… Source: Cauda equina syndrome due to posttraumatic syringomyelia in conus medullaris – A case report — Surgical Neurology International 2024; CC BY-NC-SA.

Figure 3:. Postoperative radiological findings. (a) Sagittal view of T2-weighted magnetic resonance imaging (MRI) shows almost complete disappearance of syrinx in the conus medullaris (arrow). Note… Source: Cauda equina syndrome due to posttraumatic syringomyelia in conus medullaris – A case report — Surgical Neurology International 2024; CC BY-NC-SA.

Figure 4. Source: Cauda equina syndrome due to posttraumatic syringomyelia in conus medullaris – A case report — Surg Neurol Int. 2024 Jul 12;15:243. doi: 10.25259/SNI_386_2024; CC BY-NC-SA.

Figure 1. T2-weighted magnetic resonance imaging cervical spine Source: Syringosubarachnoid shunting using a myringotomy tube — Surgical Neurology International 2016; CC BY-NC-SA.

Figure 2. Myringotomy tube Source: Syringosubarachnoid shunting using a myringotomy tube — Surgical Neurology International 2016; CC BY-NC-SA.

Figure 7. Source: Surgical treatment of idiopathic syringomyelia: Silastic wedge syringosubarachnoid shunting technique — Surg Neurol Int. 2014 Jul 24;5:114. doi: 10.4103/2152-7806.137536; CC BY-NC-SA.

Figure 1. Opening the arachnoid membrane Source: Surgical treatment of idiopathic syringomyelia: Silastic wedge syringosubarachnoid shunting technique — Surgical Neurology International 2014; CC BY-NC-SA.

Figure 2. Contoured silastic wedges Source: Surgical treatment of idiopathic syringomyelia: Silastic wedge syringosubarachnoid shunting technique — Surgical Neurology International 2014; CC BY-NC-SA.

Figure 3. Initial placement of contoured silastic wedge Source: Surgical treatment of idiopathic syringomyelia: Silastic wedge syringosubarachnoid shunting technique — Surgical Neurology International 2014; CC BY-NC-SA.

History of Present Illness

• Chief complaint: Dissociated (cape-like) sensory loss (loss of pain/temperature, preserved light touch), hand/upper extremity weakness and atrophy, neuropathic pain, scoliosis (children), progressive myelopathy
• Etiology is key (treat the cause, not just the syrinx):
  • Chiari I/II (most common — treat with posterior fossa decompression; syrinx usually improves)
  • Post-traumatic (tethering/arachnoiditis at injury level — untether/expand)
  • Post-infectious/arachnoiditis, tumor-associated, idiopathic
• Progression rate, prior decompression/shunt

Past Medical History

• Prior spinal trauma/SCI, meningitis/arachnoiditis, Chiari, prior posterior fossa or spinal surgery
• Standard PMH

Imaging Review

MRI Brain + Entire Spine (T1, T2, cine CSF flow)

• Syrinx extent/size, location, septations
• Underlying cause: Chiari (tonsillar descent, CSF flow at foramen magnum), tethering/arachnoid scar (post-traumatic — cord tethered, CSF flow block at injury level), tumor (enhancing nodule), basilar invagination
• Cine flow (CSF dynamics at foramen magnum / block level)

Labs

• CBC, BMP, Coags, type and screen

Neurological Examination

• Detailed motor (intrinsic hand), dissociated sensory mapping, reflexes, gait, scoliosis, document baseline

Surgical Planning

Case Logistics, OR Needs & Orders

• OR table/bed: radiolucent spine-capable table selected for approach, imaging, instrumentation, patient size, and alignment goals; keep abdomen free for prone cases.
• OR setup: microscope, neuromonitoring, prone positioning pads, ultrasound/navigation if needed, dural repair materials, and CSF-leak management supplies.
• Special needs: Foley for detethering/bladder baseline, urology plan when neurogenic bladder is relevant, MAP/normothermia for cord perfusion, no long paralytic with MEPs, and meticulous skin-pressure protection.
• Immediate postop orders: motor/sensory/bladder checks, flat or activity restrictions per dural closure, wound/CSF-leak watch, pain/spasm regimen, MRI follow-up when indicated, and PT/urology follow-up.

Treat the Cause First (Principle)

• Chiari-associated: posterior fossa decompression (± duraplasty) → restores CSF flow, syrinx usually shrinks (see chiari-decompression)
• Post-traumatic/arachnoiditis: untethering + expansile duraplasty at the block level (restore subarachnoid CSF flow) — preferred over shunt
• Tumor-associated: resect tumor (syrinx resolves)
• Syringo-subarachnoid/peritoneal/pleural shunt: reserved for refractory/progressive syrinx when the cause cannot be addressed or untethering fails (shunts have high failure/complication rates — last resort)

Position

• OR table/bed: radiolucent spine-capable table selected for approach, imaging, instrumentation, patient size, and alignment goals; keep abdomen free for prone cases.
• Prone, Mayfield/foam, IONM baseline; per target (foramen magnum for Chiari, syrinx level for shunt/untethering)

Key Surgical Steps (Syringosubarachnoid Shunt — refractory cases)

1. Laminectomy at the level of maximal syrinx (thinnest cord/dorsal)
2. Midline durotomy, identify the dorsally expanded cord
3. Myelotomy at the dorsal midline (or dorsal root entry zone) into the syrinx cavity (thinnest point — ultrasound-guided)
4. Drain syrinx; place a small shunt catheter from the syrinx cavity into the subarachnoid space (syringo-subarachnoid), secure to pia
5. (Alternative distal: peritoneal/pleural if subarachnoid inadequate)
6. Watertight dural closure (expansile duraplasty to maintain subarachnoid space)
   • Untethering (post-traumatic): lyse arachnoid adhesions at the block, expansile duraplasty to re-establish CSF flow (often preferred to shunting)

Critical Anatomy & Structures at Risk

1. Spinal cord tracts — myelotomy (dorsal columns), already compromised cord
2. Anterior spinal artery (ventral)
3. Dura/subarachnoid space (shunt patency, CSF flow), arachnoid (adhesions)

Equipment

• Microscope, ultrasound (syrinx localization), syrinx shunt catheter, micro-instruments, fine bipolar
• Dural substitute (duraplasty), sealant

Monitoring

• SSEPs, MEPs, EMG

Anesthesia

• MAP support, no paralytic (IONM), prone precautions

Potential Complications

1. Shunt failure/obstruction (syrinx shunts commonly fail — recurrence)
2. Neurological worsening (myelotomy), CSF leak
3. Recurrence/progression if underlying cause not addressed
4. Tethering/arachnoiditis (re-block)

Operative Note Template

Preoperative Diagnosis: [Chiari-associated / post-traumatic / idiopathic] syringomyelia at [levels]

Postoperative Diagnosis: Same

Procedure: [Posterior fossa decompression / Untethering with expansile duraplasty / Syringosubarachnoid shunt placement] for syringomyelia at [levels]

Surgeon / Assistant: Anesthesia: General endotracheal EBL / Fluids: Adjuncts: Microscope, ultrasound (syrinx localization); SSEP/MEP/EMG Implants: Dural substitute (duraplasty) [/ syrinx shunt catheter], sealant Complications: None

Indications: [Age]yo [M/F] with [progressive] syringomyelia from [etiology] causing [dissociated sensory loss/weakness/pain]. The strategy was cause-directed [posterior fossa decompression for Chiari / untethering for post-traumatic block / shunt for refractory progressive syrinx]. Risks discussed.

Description of Procedure: After consent and time-out, general anesthesia was induced and neuromonitoring established. The patient was positioned prone. [Chiari: a foramen magnum decompression with duraplasty was performed to restore CSF flow.] [Post-traumatic: a laminectomy at the block level with arachnoid lysis and expansile duraplasty re-established subarachnoid CSF flow.] [Refractory syrinx: a laminectomy was performed at the maximal/thinnest point of the syrinx, a midline (or DREZ) myelotomy made under ultrasound guidance, the syrinx drained, and a small shunt catheter placed from the syrinx into the subarachnoid space.] A watertight dural closure [/ expansile duraplasty] was performed with sealant.

Closure was completed in layers. The patient was transferred with CSF-leak precautions; gradual (months) syrinx collapse was anticipated.

Postoperative Plan

• Step-down/ICU, neuro checks, CSF leak precautions, MAP support
• MRI at 3-6 months (syrinx should shrink over months — not immediately), cine flow
• Pain management (neuropathic — gabapentinoids), rehab
• DVT prophylaxis (mechanical)
• Counsel: syrinx collapse is gradual; goal is to halt progression; monitor for recurrence/shunt failure; address scoliosis (peds, ortho)

Chief-Level Case Review

Use these as the senior-level mental model for Syringomyelia — Management / Syringosubarachnoid Shunt:

• Decision point: Trajectory and hardware choice should follow the failure mode: obstruction, infection, overdrainage, loculation, slit ventricle, distal failure, or wrong pressure setting.
• Technical lever: Document the system: entry point, catheter target/depth, valve type and setting, distal site, antibiotic-impregnated hardware, and what imaging confirms placement.
• Bailout: Rescue plan is practical: poor CSF return, bloody CSF, malposition, distal access failure, abdominal/pleural complication, or inability to safely pass the catheter.
• Postop watch: Postop orders must be unambiguous: drain height/rate/max output, valve setting, clamp parameters, imaging, antibiotics, ICP/neuro checks, and overdrainage precautions.

Common Pimp Questions

Use these to pressure-test preparation for Syringomyelia — Management / Syringosubarachnoid Shunt:

1. What neurologic level and root are responsible for the presenting deficit?
2. What is the decompression target and how will you know it is adequately decompressed?
3. What instability, deformity, bone-quality, or fusion variable changes the construct?
4. What vascular, visceral, dural, or neural structure is the main structure at risk?
5. What postop brace, drain, mobilization, MAP, antibiotic, and DVT plan should be ordered?

Attending Preference Variables

Items that commonly vary by surgeon or institution:

• Positioning frame, arms, traction, and localization workflow: [attending-specific]
• Navigation/robot/fluoro use, screw system, graft/biologic choice, and drain threshold: [attending-specific]
• Neuromonitoring modality and MAP goal for myelopathy, deformity, or cord-risk cases: [attending-specific]
• Brace, Foley, antibiotics, mobilization, and DVT prophylaxis timing: [attending-specific]