Using Intraoperative Ultrasonography for Spinal Cord Tumor Surgery

doi:10.1016/j.wneu.2016.09.097

World Neurosurgery

Volume 97, January 2017, Pages 104-111

https://doi.org/10.1016/j.wneu.2016.09.097 Get rights and content

Background

Our aim was to evaluate the usefulness of modern intraoperative ultrasonography (iUS) in the resection of a wide variety of spinal intradural pathologic entities.

Methods

We evaluated patients with spinal cord disease treated between January 2006 and September 2015. Intraoperative standard B-mode images were acquired using a 3.5-MHz to 12-MHz ultrasonographic probes (linear and curvilinear) on various ultrasound machines. The benefits and disadvantages of iUS were assessed for each case.

Results

A total number of 158 intradural spinal lesions were operated on using iUS. Of these, 107 lesions (68%) were intradural extramedullary and 51 (32%) were intramedullary. All lesions were clearly visible using the ultrasound probe. The high-frequency linear probes (10–12 MHz) provided a better image quality compared with lower-frequency probes. Color and power-angiography modes were helpful in assessing the vascularization of the tumors and location of the major vessels in the vascular lesions.

Discussion

We document how iUS was used to facilitate safe and efficient spinal tumor resection at each stage of the operation. iUS was beneficial in confirmation of tumor location and extension, planning myelotomy, and estimation of degree of resection of the intramedullary tumors. It was particularly helpful in guiding the approach in redo surgeries for recurrent spinal cord tumors.

Conclusions

iUS has a fast learning curve and offers additional intraoperative information that can help improve surgical accuracy and therefore may reduce procedure-related morbidity.

Introduction

Intraoperative ultrasonography (iUS) in neurosurgery was pioneered in the early 1980s by Chandler and Knake,¹ Dohrmann and Rubin,² and Masuzawa et al.³ By the early 1990s, Epstein et al.⁴ were consistently using it for all intramedullary tumor resections, concluding that intraoperative sonography had “permitted a more complete and better-guided radical resection of spinal cord neoplasms, with improved postoperative neurologic function.” These investigators acknowledged that resection was possible only with improved tumor localization, tumor and cyst characterization, placement of myelotomy, and tumor resection monitoring, all of which were performed under iUS visualization.

It is increasingly important to be able to identify tumor location intraoperatively as the case mix has evolved from large tumors causing neurologic deficit to small tumors identified early or even incidentally by magnetic resonance imaging (MRI). In these cases, the tumor may not be visible macroscopically on the surface of the cord.

Doppler techniques are useful in visualizing feeding arteries in tumors or vascular lesions as well as neighboring vessels. Contrast-enhanced ultrasonography is helpful in the assessment of the flow dynamics as well as in defining the border between tumor and healthy neural tissue and in detecting residual tumor. Coupling contrast-enhanced ultrasonography with virtual navigation permits one to localize these vessels in the three-dimensional frame within the surgical field. The value of these techniques has been well described in brain surgery5, 6, 7, 8 and we postulate that they can be applied with the similar success to spinal cord surgery. Similarly, it was previously shown that most brain tumors are very visible intraoperatively using B-mode ultrasonography9, 10, 11 and we hypothesize that the same applies to visualization of spinal cord tumors.

As a consequence of technologic progress, iUS is now a requisite in many operations that involve the spinal cord. iUS allows the surgeon to easily detect and assess lesions within the spinal cord, dural sac, and along the ventral aspect of the spinal cord during surgery. Intramedullary and extramedullary tumors, hematomas, abscesses, cysts, syrinxes, discs, bone, and bullet fragments can be easily located and operated on under ultrasonic guidance.12, 13, 14, 15, 16

We report our experience with iUS as an integral aid for locating and determining the resection of intradural spinal disease. We analyze the strengths and limitations of this technique as well as some unique features that other intraoperative imaging techniques cannot provide.

Section snippets

Methods

Between January 2006 and October 2015, 158 patients with intradural spinal pathologic entities underwent surgery performed by the first and last author (2006–2008) and subsequently by the first author in another hospital (2008–2015). In all cases, iUS was used for intraoperative orientation.

Intraoperative standard B-mode images were acquired using a 3.5-MHz to 12-MHz ultrasound probe (linear and curvilinear) on various ultrasound machines (Philips 3500, Philips 4000 [Amsterdam, Netherlands],

Case Mix

There were 76 males (48%) and 82 females (52%) with a mean age of 46 years, ranging from 19 months to 81 years. Of 158 lesions, 68% (107) were intradural extramedullary and 32% (51) intramedullary (Table 1). Five of the intramedullary lesions also had an extramedullary exophytic component. In 1 case, the patient underwent ultrasound-guided surgical biopsy on the basis of a positive MRI finding, but the histopathologic examination showed an inflammatory lesion.

iUS

Lesions were visible on sonographic

Discussion

We discuss the usefulness and limitations of iUS for spinal tumor surgery in a structure guided by the surgical technique itself.

Conclusions

iUS is one of the most underused imaging techniques in general neurosurgery, because of the advent of neuronavigation systems and intraoperative MRI/computed tomography. At the same time it remains the most accessible option.

In our series, we found it particularly helpful in tailoring the dural exposure and extent of myelotomy, estimation of intramedullary tumor debulking, accurate location of small intramedullary lesions, and assessment of lesional and perilesional vascularity and also in

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Intraoperative High-Resolution Color-Coded Ultrasound to Identify the Posterior Median Sulcus for Midline Myelotomy in Intramedullary Spinal Cord Surgery
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A 14-year-old boy presented with a 2-year history of slowly increasing weakness and atrophy in the right forearm and leg. Magnetic resonance imaging (MRI) revealed an intramedullary diffusely infiltrating lateralized tumor at C3–7. An extended biopsy was planned. After laminotomy and durotomy, the swollen spinal cord was noted to be rotated by 45° with the right dorsal root entry zone being in the midline. A 15 MHz linear ultrasound probe was used to identify the midline by visualizing the dorsal median sulcal vein within the midline raphe. A myelotomy was made in that zone without deterioration of somatosensory evoked potentials (SEPs) and an extended biopsy was performed. Histological examination revealed a pilocytic astrocytoma. Modern intraoperative high-resolution color-coded ultrasound enables the identification of the midline in intramedullary spinal cord lesions even when the spinal cord anatomy is distorted.
Contrast-Enhanced Ultrasound in Resection of Spinal Cord Gliomas
2023, World Neurosurgery
Intraoperative contrast-enhanced ultrasound (iCEUS) is a relatively new technique for visualizing brain gliomas and can help achieve maximum resection, but its potential in evaluation of spinal cord gliomas has not been well defined. The aim of this study was to describe the iCEUS characterization of and evaluate its role in visualizing intramedullary gliomas.
A retrospective review of patients who underwent intramedullary glioma resection with iCEUS guidance from 2019 to 2021 was conducted. An offline analysis was performed to compare and characterize the perfusion features of each glioma.
This study included 36 patients who underwent iCEUS for spinal cord gliomas. iCEUS was performed successfully, and all gliomas were clearly identified. The distribution of contrast agent showed different dynamic phases (arterial, peak, and washout) from those observed in brain gliomas, generally appearing slower and less intense in spinal cord gliomas. iCEUS helped highlight intramedullary gliomas, each of which demonstrated specific iCEUS features depending on the grade. Gross total resection was achieved in 20 patients (55.6%), subtotal resection was achieved in 11 patients (30.6%), and partial resection was achieved in 5 patients (13.8%).
ICEUS adds valuable information in highlighting spinal cord gliomas in real time. It allows the neurosurgeon to assess the anatomical location of the glioma and delineate the tumor margins. iCEUS could play a potentially important role in guiding spinal cord glioma resection. Further study with more cases is needed to better understand the microbubble distribution dynamics in intramedullary gliomas.
Systematic Review: Applications of Intraoperative Ultrasonography in Spinal Surgery
2022, World Neurosurgery
Citation Excerpt :
Kimura et al.35 discovered iUS adequately localized nerve tissue advantageously without dissection of dura. Ivanov et al.50 identified tumors and vasculature along with nervous tissue and reported a fast learning curve for iUS with improved surgical accuracy and decreased procedure-related morbidity. The task of avoiding chronic morbidity, pain, and loss of function caused by iatrogenic nerve damage is challenging during open and even more so in minimal access procedures, with the limited visual field of a smaller incision.82
As a result of increased practicality and decreased costs and radiation, interest has increased in intraoperative ultrasonography (iUS) in spinal surgery applications; however, few studies have provided a robust overview of its use in spinal surgery. We synthesize findings of existing literature on use of iUS in navigation, pedicle screw placement, and identification of anatomy during spinal interventions.
PRISMA guidelines were used in this systematic review. Studies were identified through PubMed, Scopus, and Google Scholar databases using the search string. Abstracts mentioning iUS in spine applications were included. On full-text review, exclusion criteria were implemented, including outdated studies or those with weak topic relevance or statistical power. On elimination of duplicates, multireviewer screening for eligibility, and citation search, 44 articles were analyzed.
Navigation using iUS is safe, effective, and economical. iUS registration accuracy and success are within clinically acceptable limits for image-guided navigation. Pedicle screw instrumentation with iUS is precise, with a favorable safety profile. Anatomic landmarks are reliably identified with iUS, and surgeons are overwhelmingly successful in neural or vascular tissue identification with iUS modalities, including standard B mode, Doppler, and contrast-enhanced ultrasonography. iUS use in traumatic reduction of fractures properly identifies anatomic structures, intervertebral disc space, and vasculature.
iUS eliminates radiation, decreases costs, and provides sufficient accuracy and reliability in identification of anatomic and neurovascular structures in various spinal surgery settings.
Surgical and Radiologic Prognostic Factors in Intramedullary Spinal Cord Lesions
2021, World Neurosurgery
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Intraoperative ultrasonography is helpful for adequate dural opening, tumor localization, and degree of resection.42,46 It allows the transitional zones between the tumor and the surrounding structures to be identified, defining the cleavage plane.42,46 Based on all these findings, whether a GTR is possible remains mainly an intraoperative decision.
The present study aimed to perform a comprehensive data analysis of 47 consecutive patients treated in 8 years and to observe how clinical, radiologic, and surgical factors affect early and long-term outcomes, recurrence rate, and survival.
Clinical, radiologic, and surgical data were collected retrospectively from the review of a prospectively collected database. The neurologic disability was evaluated according to the modified Rankin Scale (mRS). Radiologic data were obtained by direct measurement performed on magnetic resonance imaging (MRI). Univariate and multivariate statistical analysis was performed.
From 2008 to 2016, 47 consecutive patients underwent microsurgical resection of intramedullary lesions (28 males and 19 females; mean age, 41.2 years). Ependymoma (53.2%), astrocytoma (14.9%), hemangioblastoma (14.9%), and cavernous angioma (6.4%) were the most frequent tumor histology. The mean follow-up duration was 69.3 months. Gross total tumor resection was performed in 80.8% of cases. Forty-two patients (89.4%) were alive at last follow-up. Five-year overall survival and recurrence-free survival were 92% and 82%, respectively.
Among the examined variables, age seemed to strongly correlate with outcomes; better chances of recovery and a good postoperative outcome were observed in younger patients. Surfacing lesions had a better early functional outcome than did intramedullary located lesions. Patients' preoperative neurologic and functional status (mRS score ≤2) had a significant impact on late neurologic outcome. Progression-free survival correlated with the extent of tumor resection. Surgery should probably be performed before patients' neurologic decline, aiming to achieve maximal resection without compromising patients' quality of life.
Contrast-Enhanced Ultrasound Assisted Surgery of Intramedullary Spinal Cord Tumors: Analysis of Technical Benefits and Intra-operative Microbubble Distribution Characteristics
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Intra-operative contrast-enhanced ultrasound (CEUS) is a relatively standardized procedure in brain neurosurgery, but it is still underused in spinal cord and intramedullary tumor evaluation. We reviewed and analyzed the intra-operative data from a surgical series of patients harboring intramedullary spinal cord tumors who underwent surgery under CEUS guidance. CEUS was performed in 12 patients (age range: 13–55 y); all lesions had ill-defined boundaries or peritumoral cysts at preliminary intra-operative B-mode ultrasound. CEUS highlighted the tumors in all cases. The contrast agent's spinal distribution revealed different phases (arterial, peak, washout), as observed in the brain, but these appeared to be slower and less intense. In our experience, intra-operative CEUS allows surgeons to assess spinal cord perfusion and highlight intramedullary tumors in real time. As for other imaging modalities, ultrasound contrast agents add valuable information over baseline imaging, and their use should be fostered to better understand microbubble distribution dynamics.
Common man's intraoperative ultrasound: Basic Sonosite™ probe doubling as real time neuronavigator
2020, Interdisciplinary Neurosurgery: Advanced Techniques and Case Management
Citation Excerpt :
Its use in neurosurgery was first described by Reid in 1978. Over the years a lot of neurosurgical procedures have been reported to be guided by IOUS, i.e lesion localization in the brain [10–12] and spine [13,14], guidance of surgical resection in tumors, catheter placement, aspiration of abscess and in spinal surgery. Brain parenchyma has specific viscoelastic features that permit exceptional ultrasound propagation, also aided by the fact that the ultrasound beam is not attenuated by interposed tissue like skin or subcutaneous tissue [11].
Neuronavigation technology has become indispensable to modern Neurosurgery. There are many systems which use the patient’s pre-operative imaging data and help the surgeon navigate the brain during surgery. Systems have been developed for both intracranial, endoscopic skull base and spinal procedures. The main drawback of this method is its reliance on static pre-operative imaging data. Real-time ultrasound based navigation systems have also been introduced which help mitigate the afore-mentioned drawback. Although the use of these technologies has been proven useful, many centers are unable to replicate its use as it comes with increased cost. For centers yet to acquire such costly devices, we report our experience with the readily available, SonoSite^TM high frequency transducer in cranial and spinal neurosurgical operations. Our experience suggests that use of the SonoSite^TM high frequency transducer during common neurosurgical procedures both cranial and spinal is both user friendly and efficacious.

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Technical NoteUsing Intraoperative Ultrasonography for Spinal Cord Tumor Surgery

Background

Methods

Results

Discussion

Conclusions

Introduction

Section snippets

Methods

Case Mix

iUS

Discussion

Conclusions

Surg Neurol

Radiol Clin North Am

Clin Neurol Neurosurg

Intraoperative use of ultrasound in neurosurgery

Clin Neurosurg

Neurol Med Chir (Tokyo)

Intraoperative ultrasonography: an important surgical adjunct for intramedullary tumors

J Neurosurg

From grey scale b-mode to elastosonography: multimodal ultrasound imaging in meningioma surgery-pictorial essay and literature review

BioMed Res Int

Ultrasound contrast imaging research

Ultrasound Q

Principles of cerebral ultrasound contrast imaging

Cerebrovasc Dis

Assistance of intraoperative microvascular Doppler in the surgical obliteration of spinal dural arteriovenous fistula: cases description and technical considerations

Acta Neurochir (Wien)

A practical grading system of ultrasonographic visibility for intracerebral lesions

Acta Neurochir (Wien)

Technical Note
Using Intraoperative Ultrasonography for Spinal Cord Tumor Surgery