Intra-operative high frequency ultrasound improves surgery of intramedullary cavernous malformations

Abstract

Intra-operative ultrasound (ioUS) is a very useful tool in surgery of spinal lesions. Here we focus on modern ioUS to analyze its use for localisation, visualisation and resection control in intramedullary cavernous malformations (IMCM). A series of 35 consecutive intradural lesions were operated in our hospital in a time period of 24 months using modern ioUS with a high frequency 7-15 MHz transducer and a true real time 3D transducer (both Phillips iU 22 ultrasound system). Six of those cases were treated with the admitting diagnosis of a deep IMCM (two cervical, four thoracic lesions). IoUS images were performed before and after the IMCM resection. Pre-operative and early postoperative MRI images were performed in all patients. In all six IMCM cases a complete removal of the lesion was achieved microsurgically resulting in an improved neurological status of all patients. High frequency ioUS emerged to be a very useful tool during surgery for localization and visualization. Excellent resection control by ultrasound was possible in three cases. Minor resolution of true real time 3D ioUS decreases the actual advantage of simultaneous reconstruction in two planes. High frequency ioUS is the best choice for intraoperative imaging in deep IMCM to localize and to visualize the lesion and to plan the perfect surgical approach. Additionally, high frequency ioUS is suitable for intra-operative resection control of the lesion in selected IMCM cases. Methods: A series of 35 consecutive intradural lesions were operated in our hospital in a time period of 24 months using modern ioUS with a high frequency 7-15 MHz transducer and a true real time 3D transducer (both Phillips iU 22 ultrasound system).Six of those cases were treated with the admitting diagnosis of a deep IMCM (two cervical, four thoracic lesions). IoUS images were performed before and after the IMCM resection. Pre-and early postoperative MRI images were performed in all patients.Results: In all six IMCM cases a complete removal of the lesion was achieved microsurgically resulting in an improved neurological status of all patients. High frequency ioUS emerged to be a very useful tool during surgery for localization and visualization. Excellent resection control by ultrasound was possible in 3 cases. Minor resolution of true real time 3D ioUS decreases the actual advantage of simultaneous reconstruction in 2 planes. Conclusion:High frequency ioUS is the best choice for intra-operative imaging in deep IMCM to localize and to visualize the lesion and to plan the perfect surgical approach.Additionally, high frequency ioUS is suitable for intra-operative resection control of the lesion in non acute IMCM cases. Resection control in acute IMCM lesions is difficult to interpret since sometimes perifocal edema and/or perifocal hemosiderin can hinder the accurate differentiation of medullary to pathological tissue.

Surgical outcomes and natural history of intramedullary spinal cord cavernous malformations: a single-center series and meta-analysis of individual patient data

“…Eligibility criteria were met by 39 articles, totaling 608 patients 1,5,6,8,9,11,12,14,15,17,[20][21][22][23]27,28,30,[34][35][36][37][38][39][40][41][42]45,46,49,50,53,54,58,59,[62][63][64]67,73 (Fig. 1), in addition to our institutional series of 24 patients with ISCCMs (total of 40 series and 632 patients).…”

“…Included articles described use of various methods to report outcomes, most commonly a simple scale of better, same, or worse. Several articles reported use of a standardized scoring tool for assessing neurological function, including the McCormick, 1,12,15,17,20,30,35,37,39,40 Frankel, 5,6,8,42,53,59,73 American Spinal Injury Association impairment, 50 and Aminoff-Logue disability 36 scales. For each included study, we defined improved, unchanged, or worsened neurological function the same as that reported by the authors of eligible articles.…”

“…7,24,73 Since then, several additional large series have been published. 1,2,6,12,17,20,27,32,34,36,37,39,42,59,62,67 Because of the relative rarity of these lesions, information pertaining to clinical outcomes for patients harboring ISCCMs is scarce.…”

“…The traditional approach to deep-seated ISCCMs without sur- face abnormalities is midline myelotomy. 43 Good results have also been reported from use of various localization techniques to guide myelotomy, including intraoperative ultrasonography 5,6 and indocyanine green videoangiography. 20 Other options for more ventral or lateral lesions include myelotomy through the dorsal root entry zone, 43 anterolateral partial vertebrectomy or corpectomy, 19,45 and radical facetectomy and dentate ligament resection.…”

Intramedullary spinal cavernoma: clinical presentation, microsurgical approach, and long-term outcome in a cohort of 48 patients

“…To improve targeting of the approach and minimize surgical trauma, ultrasonography was used before opening the dura mater. 3,32 Myelotomy was performed via the posterior median sulcus (dorsal midline entry zone), lateral through the dorsolateral entry zone, or directly into the pathology (Fig. 3).…”