Magnetic Resonance Imaging Signal Characteristics of Medishield: Early Postoperative Profile in a Rabbit Interlaminotomy Model.

Nevzati, Edin; Berberat, Jatta; Soleman, Jehuda; Coluccia, Daniel; Muroi, Carl; Schöpf, Salome; Lukes, Anton; Fischer, Ingeborg; Remonda, Luca; Fandino, Javier; Marbacher, Serge (2017). Magnetic Resonance Imaging Signal Characteristics of Medishield: Early Postoperative Profile in a Rabbit Interlaminotomy Model. World neurosurgery, 98, 704-710.e3. Elsevier 10.1016/j.wneu.2016.12.002

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Application of Medishield to the nerve root is common during spinal surgery to create a mechanical barrier from pain mediators and reduce scar formation. However, Medishield's signal characteristics on magnetic resonance imaging (MRI) have not yet been examined.


Microsurgical interlaminotomy was performed on 2 lower lumbar segments in 17 adult New Zealand white rabbits. After dural exposure, applications of 1 mL (autologous blood clot or Medishield) were randomized for each level. On postoperative days 1 through 3, various MRI sequences in 1.5T were performed including T1-weighted, T2-w, T1-gadolinium-weighted, susceptibility-weighted and turbo inversion recovery magnitude (TIRM) sequence. Signaling characteristics were analyzed by 3 blinded observers. Inter-rater agreement was calculated using Fleiss's kappa coefficient (κ). Positive and negative likelihood ratios in detecting Medishield by MRI were determined.


Of 24 MRIs performed, TIRM sequence identified Medishield with the highest likelihood ratio. Medishield's positive likelihood ratio was highest (5.8) on postoperative day 1 with interobserver agreement of 93% (κ = 0.75); these rates declined to 2.5 and 1.4 on postoperative days 2 and 3 with interobserver agreements of 71% (κ = 0.43) and 83% (κ = 0.67), respectively. Medishield adherence was confirmed in each rabbit by histologic examinations.


Understanding that radiologic detection of Medishield diminished over time as its signal characteristics became less distinguishable from a blood clot is essential in clinical practice. Medishield was detected on postoperative day 1 but not 2 days later after hemodynamic changes had occurred. These results may provide a guide for postoperative findings, such as differential diagnosis of hematoma.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Pre-clinic Human Medicine > BioMedical Research (DBMR) > Forschungsbereich Mu50 > Forschungsgruppe Neurochirurgie

UniBE Contributor:

Fandino, Javier, Marbacher, Serge


600 Technology > 610 Medicine & health








Marceline Brodmann

Date Deposited:

27 Sep 2022 12:17

Last Modified:

05 Dec 2022 16:25

Publisher DOI:


PubMed ID:


Uncontrolled Keywords:

Animal model Interlaminotomy model Lumbar disk disease Magnetic resonance imaging Medishield New Zealand white rabbit Postoperative fibrosis




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