Decreased MEPs during subcutaneous dissection for untethering surgery of a “true” lipomyelomeningocele: aggravated traction of the spinal cord by release of the sac from the original nest

  • Kyung Hyun Kim
  • Sangjoon Chong
  • Ji Yeoun Lee
  • Keewon Kim
  • Seung-Ki Kim
  • Kyu-Chang WangEmail author
Case Report



It is well known that the preoperative enlarged sac in occult spinal dysraphism, in which the spinal cord is attached to its dome, can be associated with neurological deficits by aggravation of spinal cord traction. We experienced a similar phenomenon during the early stage of untethering surgery for “lipomyelomeningocele in a strict sense (LMMC).”

Clinical presentation

We report a case of a 3-month-old girl with LMMC, which showed decreased motor evoked potentials (MEPs) in the lower extremities during the early stage of untethering surgery. The sac was released from the original nest by incision with separation of the overlying skin and dissection from the muscle fascia. The sac became rounder, and the spinal cord attached to the dome of the sac was further stretched. After aspiration of cerebrospinal fluid from the sac, the MEPs recovered. Postoperatively, the patient had no neurological deficits.


Although this phenomenon rarely occurs, release of the herniated sac of LMMC from the original nest during the early stage of untethering surgery may result in neurological changes. Application of intraoperative neurophysiological monitoring helps to detect electrophysiological deterioration and can prevent neurological deficits.


Intraoperative neurophysiological monitoring Lipomyelomeningocele (LMMC) Untethering Spinal cord traction 


Funding information

This study was supported by grant no. 04-2013-1100 from the Seoul National University Hospital Research Fund.

Compliance with ethical standards

Conflict of interest

The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper.


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  • Kyung Hyun Kim
    • 1
  • Sangjoon Chong
    • 1
    • 2
  • Ji Yeoun Lee
    • 1
    • 3
  • Keewon Kim
    • 4
  • Seung-Ki Kim
    • 1
  • Kyu-Chang Wang
    • 1
    Email author
  1. 1.Division of Pediatric NeurosurgerySeoul National University Children’s HospitalSeoulRepublic of Korea
  2. 2.Department of NeurosurgeryAsan Medical CenterSeoulRepublic of Korea
  3. 3.Department of AnatomySeoul National University College of MedicineSeoulRepublic of Korea
  4. 4.Department of Rehabilitation MedicineSeoul National University HospitalSeoulRepublic of Korea

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