Peel-Away Sheath Introducer [Neurosurgery Wiki]

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===== Peel-Away Sheath Introducer =====

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A **[[peel-away]] sheath introducer** is a **flexible medical device** used primarily in **vascular access procedures**. It consists of a thin-walled plastic tube (the **sheath**) and an internal dilator that allows the sheath to be introduced into a vessel or body cavity. Once access is achieved, the sheath enables the introduction of catheters, pacemaker leads, or other devices.

What makes it unique is its **“peel-away” capability**:  
After insertion, the sheath can be **split longitudinally and removed** without displacing the indwelling catheter or device. This is done by pulling apart the two pre-scored halves of the sheath using small side wings or tabs.

==== Typical Uses ====
  * Central venous catheter placement  
  * Peritoneal dialysis catheter introduction  
  * Temporary pacing wire insertion  
  * Electrophysiology procedures

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A [[ventriculoatrial shunt]] (VAS) proves to be an excellent [[alternative]] in the [[hydrocephalus treatment]]. Its usage is a viable [[option]] when [[ventriculoperitoneal shunt]] (VPS) is contraindicated in any age of patients.

A report highlights a successful case involving a 6-month-old patient who underwent VAS catheter positioning. The child presented with hydrocephalus and biliary atresia, making him a candidate for a liver transplant. Notably, a VPS was considered a relative contraindication in this scenario.

The VAS emerges as a viable option for patients in whom a VPS might be contraindicated. This case demonstrates the successful application of a VAS in a pediatric patient
((Isaza JPL, Vallejo S, Aristizabal JH, Rosales-Camargo SA, Perilla-Estrada JP, Rueda DQ. The "[[peel-away]]" [[technique]] for a [[ventriculoatrial shunt]] in a 6-month-old patient: A case report. Surg Neurol Int. 2024 Jan 19;15:16. doi: 10.25259/SNI_724_2023. PMID: 38344081; PMCID: PMC10858777.)).

==== Not Designed For ====
  * Brain surgery  
  * Structural tissue retraction  
  * Intracranial trajectory control

==== Synonyms ====
  * Splittable introducer sheath  
  * Tear-away sheath  
  * Disposable vascular sheath

==== Reference Example ====
> Common sizes: 7F to 24F  
> Materials: Medical-grade polyurethane or PTFE  
> Sterile, single-use  
> Often included in vascular access kits

===== Technical note and retrospective case series =====
 
In a technical note and retrospective case series Siomin et al.
((Siomin E, McDermott M, Castaldi A, Siomin V. Minimally Invasive and Cost-Effective Access to Deep-Seated Intracranial Lesions Using 19F Peel-Away Sheath Introducer and "Dynamic" Retraction: Technical Note and a Case Series. Oper Neurosurg (Hagerstown). 2024 Nov 4;29(1):118-124. doi: 10.1227/ons.0000000000001403. PMID: 40522350.))
propose a low-cost, minimally invasive technique for resecting deep-seated brain lesions using a 19F peel-away sheath introducer and so-called "dynamic" retraction.
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==== 🚨 Conceptual Weaknesses ====
  * **Improvised Device Misuse:**  
    The 19F peel-away sheath is a vascular introducer, not a neurosurgical retractor. Its intraaxial use is **unsafe and non-validated**, and its deployment in delicate brain regions borders on reckless.

  * **"Dynamic Retraction" = Euphemism:**  
    This term conceals the absence of trajectory control or stable visualization. Manual dynamic retraction lacks the biomechanical integrity of dedicated MIS systems, increasing the risk of cortical and subcortical injury.

==== 📉 Methodological Flaws ====
  * **Small, Heterogeneous Cohort:**  
    Combining diverse pathologies (GBM, metastases, cysts) in one case series prevents any meaningful extrapolation. The sample is too small to reach safety or efficacy conclusions.

  * **No Objective Outcomes:**  
    Gross total resection is claimed without imaging confirmation protocols. Functional outcomes are anecdotal. No mention of validated scales (e.g., mRS, KPS, RANO).

  * **No Comparator Arm:**  
    Without parallel use of standard tubular retractors or image-guided MIS systems, claims of equivalence or superiority are speculative at best.

  * **No Real Cost Analysis:**  
    "Cost-effective" is asserted without breakdowns of device pricing, hospital stay, complication management, or reinterventions.

==== 🎭 Academic Theater ====
  * **Performative Minimalism:**  
    The procedure is labeled "minimally invasive," yet lacks essential MIS elements: rigid tubular control, navigated access, and standardized closure techniques.

  * **Marketing Disguised as Science:**  
    The article has the tone of a promotional piece rather than an objective technical report. It risks encouraging **substandard neurosurgery** in low-resource settings.

==== 💬 Final Judgment ====
This publication represents a **dangerous oversimplification** of MIS principles. Far from offering a viable alternative, it **undermines surgical safety** in favor of expediency. The technique should **not be adopted without rigorous validation** and biomechanical studies.

==== Recommendation ====
> '''Do not recommend for clinical adoption.'''  
> '''Further research required with ethical oversight, controls, and functional imaging.'''