Ultrasound Elastography in Neurosurgery: Current Applications and Future Perspectives.

BACKGROUND: Similar to clinical palpation, Ultrasound elastography (USE) helps distinguish between tissues by providing information on their elasticity. While it has been widely explored and has been applied to many body organs, USE has not been studied as extensively for application in neurosurgery. The current systematic review was performed to identify articles related to the use of interoperative USE in neurosurgery. METHODS: Search included MEDLINE(R) database. Only original peer-reviewed full-text articles were included. No language or publication year restrictions were imposed. Two independent reviewers assessed the search results for relevance. The identified articles were screened by title, abstract, and full-text review. RESULTS: Seventeen articles were included in the qualitative analysis and 13 articles were related to oncology, epilepsy (n = 3), and spine (n = 1). In oncology, USE was found useful in defining tumor stiffness, aiding surgical planning, detecting residual tumors, discriminating between tumor and brain tissue, and differentiating between different tumors. In epilepsy, USE could improve the detection of epileptogenic foci, thereby enhancing the prospect of complete and safe resection. The application in spinal surgery was limited to demonstrating that a compressed spinal cord is stiffer than the decompressed one. CONCLUSIONS: USE was found to be a safe, quick, portable, and economic tool that was a useful intraoperative adjunct to provide information corresponding to a variety of neurosurgical diseases, at different stages of surgery. This review describes the current intraoperative neurosurgical applications of USE, the concept of elasticity, and different USE modalities as well as the technical challenges, limitations, and possible future implications.

Aggressive surgical management of recurrent intracranial juvenile xanthogranuloma: case report and review of the literature.

INTRODUCTION: Juvenile xanthogranuloma (JXG) with the central nervous system (CNS) involvement is a rare disease entity that remains poorly understood, especially when the condition develops following treatment for Langerhans cell histiocytosis (LCH). CASE REPORT: A 21-year-old man who was diagnosed with LCH at age 2, several years following which he developed signs and symptoms of CNS involvement. Magnetic resonance imaging (MRI) of the brain revealed JXG with bilateral choroid plexus involvement. As radiation therapy for the intraventricular masses proved unsuccessful, he underwent two surgical resections. In the following years, he developed another large JXG in the meninges, which was managed conservatively until he required surgery due to symptom progression. Twelve years after the first surgery, the patient is in stable condition with no evidence of recurrence. CONCLUSION: Due to the rarity of JXG in the CNS, optimal treatment strategies and the precise duration of therapy remain to be determined. Future studies should aim to develop an appropriate treatment algorithm for such rare cases.

In vivo assessment of spinal cord elasticity using shear wave ultrasound in dogs.

OBJECTIVE: Evaluation of living tissue elasticity has wide applications in disease characterization and prognosis prediction. Few previous ex vivo attempts have been made to characterize spinal cord elasticity (SCE). Recently, tissue elasticity assessment has been clinically feasible using ultrasound shear wave elastography (SWE). The current study aims to characterize SCE in healthy dogs, in vivo, utilizing SWE, and to address SCE changes during compression. METHODS: Ten Greyhound dogs (mean age 14 months; mean weight 14.3 kg) were anesthetized and tracheally intubated, with hemodynamic and neurological monitoring. A 3-level, midcervical laminectomy was performed. SCE was assessed at baseline. Next, 8- and 13-mm balloon compressions were sequentially applied ventral to the spinal cord. RESULTS: The mean SCE was 18.5 ± 7 kPa. Elasticity of the central canal, pia mater, and dura mater were 21.7 ± 9.6 kPa, 26.1 ± 14.8 kPa, and 63.2 ± 11.5 kPa, respectively. As expected, the spinal cord demonstrated less elasticity than the dura mater (p < 0.0001) and pia mater (trend toward significance p = 0.08). Notably, the 13-mm balloon compression resulted in a stiffer spinal cord than at baseline (233 ± 73 kPa versus 18.5 ± 7 kPa, p < 0.0001) and 8-mm balloon compression (233 ± 73 kPa versus 185 ± 68 kPa, p < 0.048). CONCLUSIONS: In vivo SCE evaluation using SWE is feasible and comparable to earlier reports, as demonstrated by physical sectioning of the spinal cord. The compressed spinal cord is stiffer than a free spinal cord, with a linear increase in SCE with increasing mechanical compression. Knowledge of the biomechanical properties of the spinal cord including SCE has potential implications for disease management and prognosis.

Quantitative assessment of vertebral artery anatomy in relation to cervical pedicles: surgical considerations based on regional differences.

OBJECTIVE: To quantify the anatomic relationship between the Cervical pedicle screw (CPS), vertebral artery (VA), and related anatomic structures in the Saudi population. METHODS: This retrospective single center study included 50 consecutive patients (35 males) with normal neck findings on computed tomography angiography performed for trauma or vascular evaluation between 2012 and 2014. Radiologic parameters were assessed and correlated with age, weight, height, and body mass index (BMI). RESULTS: Mean age, weight, height, and BMI were 45.74+/-18.93 years, 79.72+/-21.80 kg, 164.74+/-11.53 cm, and 29.38+/-6.13 kg/m2, respectively. Mean cervical pedicle diameter (PD) increased from the cranial to caudal vertebrae (p=0.0001). Mean free zone (FZ) value, defined as the distance between the lateral CP border and medial VA border, was 1 mm (range 0.95-1.16 mm). The VA entry into the transverse foramina was at C6 level on both the right 92% and left side in most patients 94%. However, the right and left side level of VA entry differed in 14% of individuals. CONCLUSION: The PD and FZ are smaller in Saudi Arabians than in western populations. Assessment of VA entry at each level should be performed on an individual basis as the level of VA entry can differ in the same patient. Anatomic variations between different geographic areas should be studied to provide better surgical guidance.

Tumors of the lateral and third ventricle: surgical management and outcome analysis in 42 cases.

OBJECTIVE: To discuss the clinical presentation, pathological diagnosis, and surgical outcome for a series of 42 consecutive patients treated for lateral and third ventricular tumors. METHODS: This is a retrospective series study conducted between 2001 and 2015 and included 42 patients (mean age: 25 years; range: 2 months-65 years) with lateral and third ventricle tumors surgically treated at King Khaled University Hospital, Riyadh, Kingdom of Saudi Arabia. Demographic, clinical, radiological, surgical, histopathological, and follow up data were analyzed. RESULTS: The most common symptoms at presentation included headache (69%), nausea/vomiting (38%), visual deficits (24%), and seizures (17%). Lesions were located in the lateral ventricle in 15 patients, third ventricle in 20 patients, and involved both the lateral and third ventricles in 7 patients. The most common tumor types in the overall cohort were colloid cysts (n=6) and pineal tumors (n=6). The postoperative complication rate was 36%. The most common postoperative complications were seizure and hydrocephalus (n=5 each, 12%). Surgical mortality was 5%. CONCLUSION: The selection of the surgical approach for intraventricular tumor resection is fundamentally dependent on the surgeon`s experience and preference. We recommend that this decision be based on the anatomic considerations that provide the best and safest access to the mass, rather than on the risk of seizure following transcortical approach.