Vol 54, No 1 (2020)
Research Paper
Published online: 2020-01-16

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Reliability of diffusion tensor tractography of facial nerve in cerebello-pontine angle tumours

Tomasz Szmuda1, Paweł Słoniewski1, Shan Ali2, Pedro M. Gonçalves Pereira3, Mateusz Pacholski2, Fanar Timemy2, Agnieszka Sabisz4, Edyta Szurowska4, Sara Kierońska1
Pubmed: 31956974
Neurol Neurochir Pol 2020;54(1):73-82.


Aim of the study. This study aimed to verify the accuracy of preoperative visualisation of the facial nerve (FN) by magnetic resonance-based (MR) diffusion tensor imaging-fibre tracking (DTI-FT) with neuronavigation system integration in patients with cerebello-pontine angle (CPA) tumours.

Clinical rationale for the study. Complete excision with preservation of the FN remains the critical goal of today’s vestibular schwannoma (VS) surgery. DTI-FT of the FN with neuronavigation is yet to be fully evaluated, and could make surgery safer.

Materials and methods. This was a prospective cohort study in which 38 consecutive patients with a CPA tumour (32 VSs, five meningiomas and one epidermoid cyst) were operated on via the retrosigmoid route from 2013 to 2019. The course of the FN was simulated before surgery using StealthViz and the images were transferred to the Medtronic S7 neuronavigation system. The FN location reconstructed by DTI-FT was verified during the surgery.

Results. MR acquisition was inappropriate in three patients (7.9%). DTI-FT correctly predicted the course of the FN in 31 of the 38 patients; the discordance rate was 18.4%. The accuracy of DTI-FT was 81.6% (95% CI: 65.67-92.26), sensitivity 88.57% (95% CI: 73.26-96.80) and positive predictive value was 91.18% (95% CI: 90.17-92.09). The reliability of the neuronavigation-integrated visualisation of the FN did not depend on the tumour size (p = 0.85), but the method was more accurate when the nerve was compact in shape (p = 0.03, area under curve (AUC) 0.87, 95% CI: 0.60-1.00) and in females (p = 0.04, AUC 0.78, 95% CI: 0.56-1.00). Following surgery, 86.5% of the patients presented with useful facial function (House-Brackmann grades I-III). Correct simulation of the FN did not prevent postoperative facial palsy (p = 0.35).

Conclusions. The accuracy of DTI-FT of the FN integrated with neuronavigation remains unsatisfactory. This method does not provide any clinical benefit over non-integrated DTI-FT in terms of nerve function preservation.

Clinical implications. Due to the low reliability of the predictions, further technical advances in predicting the course of the FN are awaited by clinicians. However, DTI-FT images in the operating theatre would make tumour excision more comfortable for the surgeon.

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  1. Rinaldi V, Casale M, Bressi F, et al. Facial nerve outcome after vestibular schwannoma surgery: our experience. J Neurol Surg B Skull Base. 2012; 73(1): 21–27.
  2. Starnoni D, Daniel RT, Tuleasca C, et al. Systematic review and meta-analysis of the technique of subtotal resection and stereotactic radiosurgery for large vestibular schwannomas: a "nerve-centered" approach. Neurosurg Focus. 2018; 44(3): E4.
  3. Baro V, Landi A, Brigadoi S, et al. Preoperative Prediction of Facial Nerve in Patients with Vestibular Schwannomas: The Role of Diffusion Tensor Imaging-A Systematic Review. World Neurosurg. 2019; 125: 24–31.
  4. Savardekar AR, Patra DP, Thakur JD, et al. Preoperative diffusion tensor imaging-fiber tracking for facial nerve identification in vestibular schwannoma: a systematic review on its evolution and current status with a pooled data analysis of surgical concordance rates. Neurosurg Focus. 2018; 44(3): E5.
  5. Samala R, Borkar SA, Sharma R, et al. Effectiveness of preoperative facial nerve diffusion tensor imaging tractography for preservation of facial nerve function in surgery for large vestibular schwannomas: Results of a prospective randomized study. Neurol India. 2019; 67(1): 149–154.
  6. Li H, Wang L, Hao S, et al. Identification of the Facial Nerve in Relation to Vestibular Schwannoma Using Preoperative Diffusion Tensor Tractography and Intraoperative Tractography-Integrated Neuronavigation System. World Neurosurg. 2017; 107: 669–677.
  7. Borkar SA, Garg A, Mankotia DS, et al. Prediction of facial nerve position in large vestibular schwannomas using diffusion tensor imaging tractography and its intraoperative correlation. Neurol India. 2016; 64(5): 965–970.
  8. Simon NG, Cage T, Narvid J, et al. High-resolution ultrasonography and diffusion tensor tractography map normal nerve fascicles in relation to schwannoma tissue prior to resection. J Neurosurg. 2014; 120(5): 1113–1117.
  9. Taoka T, Hirabayashi H, Nakagawa H, et al. Displacement of the facial nerve course by vestibular schwannoma: preoperative visualization using diffusion tensor tractography. J Magn Reson Imaging. 2006; 24(5): 1005–1010.
  10. Jacquesson T, Frindel C, Kocevar G, et al. Overcoming Challenges of Cranial Nerve Tractography: A Targeted Review. Neurosurgery. 2019; 84(2): 313–325.
  11. Shapey J, Vos SB, Vercauteren T, et al. Clinical Applications for Diffusion MRI and Tractography of Cranial Nerves Within the Posterior Fossa: A Systematic Review. Front Neurosci. 2019; 13: 23.
  12. Koos WT, Day JD, Matula C, et al. Neurotopographic considerations in the microsurgical treatment of small acoustic neurinomas. J Neurosurg. 1998; 88(3): 506–512.
  13. Sun MZ, Oh MC, Safaee M, et al. Neuroanatomical correlation of the House-Brackmann grading system in the microsurgical treatment of vestibular schwannoma. Neurosurg Focus. 2012; 33(3): E7.
  14. Elm Ev, Altman D, Egger M, et al. The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: guidelines for reporting observational studies. Journal of Clinical Epidemiology. 2008; 61(4): 344–349.
  15. Sampath P, Rini D, Long DM. Microanatomical variations in the cerebellopontine angle associated with vestibular schwannomas (acoustic neuromas): a retrospective study of 1006 consecutive cases. J Neurosurg. 2000; 92(1): 70–78.
  16. Churi ON, Gupta S, Misra BK. Correlation of Preoperative Cranial Nerve Diffusion Tensor Tractography with Intraoperative Findings in Surgery of Cerebellopontine Angle Tumors. World Neurosurg. 2019; 127: e509–e516.
  17. Szmuda T, Słoniewski P, Sabisz A, et al. Traktografia nerwu twarzowego w guzach kąta mostowo-móżdżkowego. Otorynolaryngologia. 2015; 13: 42–50.
  18. Roundy N, Delashaw JB, Cetas JS. Preoperative identification of the facial nerve in patients with large cerebellopontine angle tumors using high-density diffusion tensor imaging. J Neurosurg. 2012; 116(4): 697–702.
  19. Choi KS, Kim MS, Kwon HG, et al. Preoperative identification of facial nerve in vestibular schwannomas surgery using diffusion tensor tractography. J Korean Neurosurg Soc. 2014; 56(1): 11–15.
  20. Zhang Y, Chen Y, Zou Y, et al. Facial nerve preservation with preoperative identification and intraoperative monitoring in large vestibular schwannoma surgery. Acta Neurochir (Wien). 2013; 155(10): 1857–1862.
  21. Yoshino M, Kin T, Ito A, et al. Feasibility of diffusion tensor tractography for preoperative prediction of the location of the facial and vestibulocochlear nerves in relation to vestibular schwannoma. Acta Neurochir (Wien). 2015; 157(6): 939–46; discussion 946.
  22. Wei PH, Qi ZG, Chen Ge, et al. Identification of cranial nerves near large vestibular schwannomas using superselective diffusion tensor tractography: experience with 23 cases. Acta Neurochir (Wien). 2015; 157(7): 1239–1249.
  23. Gerganov VM, Giordano M, Samii M, et al. Diffusion tensor imaging-based fiber tracking for prediction of the position of the facial nerve in relation to large vestibular schwannomas. J Neurosurg. 2011; 115(6): 1087–1093.
  24. Jacquesson T, Cotton F, Frindel C. MRI Tractography Detecting Cranial Nerve Displacement in a Cystic Skull Base Tumor. World Neurosurg. 2018; 117: 363–365.
  25. Yoshino M, Kin T, Ito A, et al. Diffusion tensor tractography of normal facial and vestibulocochlear nerves. Int J Comput Assist Radiol Surg. 2015; 10(4): 383–392.
  26. Zolal A, Juratli TA, Podlesek D, et al. Probabilistic Tractography of the Cranial Nerves in Vestibular Schwannoma. World Neurosurg. 2017; 107: 47–53.
  27. Yoshino M, Kin T, Ito A, et al. Combined use of diffusion tensor tractography and multifused contrast-enhanced FIESTA for predicting facial and cochlear nerve positions in relation to vestibular schwannoma. J Neurosurg. 2015; 123(6): 1480–1488.
  28. Pereira P, Manacas R. Magnetic Resonance Imaging Fusion of Cranial Nerves Impaired by Skull Base Tumors: A Technical Development. Journal of Nuclear Medicine & Radiation Therapy. 2019; 10(1).
  29. Breun M, Nickl R, Perez J, et al. Vestibular Schwannoma Resection in a Consecutive Series of 502 Cases via the Retrosigmoid Approach: Technical Aspects, Complications, and Functional Outcome. World Neurosurg. 2019; 129: e114–e127.

Neurologia i Neurochirurgia Polska