Assessment of Intraoperative Spinal Angiography via the Popliteal Artery for Spinal Vascular Diseases.

OBJECTIVE: Intraoperative spinal angiography via the popliteal artery for patients in the prone position has been reported only twice in 4 patients. This study aimed to clarify the safety precautions to be taken with this technique in a larger patient cohort. METHODS: Seven patients with spinal vascular disorders underwent intraoperative spinal angiography in the prone position via the popliteal artery. Ultrasound was used to evaluate the neurovascular anatomy in the popliteal fossa and guide the arterial puncture. Patient characteristics, features of angiography devices, puncture attempts, and angiography-related complications, such as hematoma formation and injury to the neurovascular bundle, were analyzed. RESULTS: The average number of arterial puncture attempts was 1.3 times (range: 1-2). Sheaths (4 and 4.5 Fr) with different ineffective lengths were used. In 1 case, a 4.5-Fr sheath was replaced with a 4-Fr sheath with a shorter noneffective length as the length of the catheter limited access to the target. Catheters with Type-JB2 tip shapes were used for craniocervical junction lesions, and those with Type-KAGAWA tip shapes were used for thoracic and lumbar spinal lesions. No puncture site complications were observed in any patient. CONCLUSIONS: Intraoperative spinal angiography via the popliteal artery was an effective tool in surgeries for spinal vascular diseases. The introduction of the ultrasound enabled atraumatic puncture of the popliteal artery. Spinal targets above T5 to T6 may be inaccessible from the popliteal fossa when using a 100-cm-long catheter.

Hemodynamic Assessment of a Large Pulmonary Arteriovenous Malformation in a Neonate: Case Report and Review of Literature.

Herein we report the case of a neonate with a prenatally diagnosed large pulmonary arteriovenous malformation, managed with minimally invasive hemodynamic monitoring in our Neonatal Intensive Care Unit. The combination of Near-Infrared Spectroscopy and Pressure Recording Analytical Method could guide neonatal management of critical cases of vascular anomalies: immediate data are offered to clinicians, from which therapeutic decisions such as timing of surgical resection are made to achieve a positive outcome. We also systemically collected and summarized information on patients' characteristics of previous cases reported in literature to data, and we compared them to our case.

Hospital complications and costs of spinal arteriovenous malformations in the United States from 2002-2014.

BACKGROUND: Spinal arteriovenous malformations (AVMs) are rare disease entities with significant morbidity if untreated. Risk factors of complications, hospitalization and costs-of-care remain in need of characterization. METHODS: Using the National Inpatient Sample years 2002-2014, adult subjects with spinal AVMs who underwent either laminectomy with lesion excision or endovascular embolization were extracted using ICD-9-CM diagnostic code 747.82. Predictors of inpatient complications, hospital length of stay (HLOS), and discharge home were evaluated using multivariable regression. Cost was evaluated using inflation-adjusted healthcare cost [charge*(cost/charge ratio)]. Mean differences (B), odds ratios (OR) and 95% CIs are reported. Significance was assessed at P<0.001. RESULTS: In 2546 weighted admissions, age was 54.4±16.5-years (laminectomy: 70.0%, embolization: 30.0%). Fifteen percent suffered inpatient complications. Cost of hospitalization was $ 41216±38511 and was elevated for subjects with complications ($67571±2636, vs. no complications: $36562±723, P<0.001). Increased costs for categories of complications ranged from $ 16525 (renal/urinary) to $62246 (thromboembolism). In surgical subjects, complications were more costly ($ 69761±2896, vs. no complications: 36520±809, P<0.001). On multivariable analysis, major/extreme disease severity and major/extreme mortality risk were associated with increased complications and HLOS (P<0.001). Elective admissions had shorter HLOS (B=-4.3-days, [-4.8, -3.8], P<0.001) and higher odds of discharge home (OR=2.6 [2.1-3.2], P<0.001). Laminectomy (vs. embolization) was associated with complications (OR=2.6, 95% CI [1.7-3.8], P<0.001), HLOS (B=3.4-days [2.9-4.0], P<0.001), and decreased discharge home (OR=0.3 [0.2-0.4], P<0.001). CONCLUSIONS: In spinal AVMs, high disease severity, non-elective admissions, and surgery are associated with complications, HLOS, and discharge to a non-home facility. Costs are elevated in patients suffering complications. Future studies are warranted.

Impact of uncertainties in range and RBE on small field proton therapy.

The objective of this paper is to evaluate the clinical impact of biological uncertainties in small field proton therapy due to the assumption of using a constant relative biological effectiveness (RBE) value of 1.1 (RBE-fixed) compared to a variable RBE (RBE-weighted). In this context the impact of the applied range margin was investigated. Eight patients with arteriovenous malformation (AVM) treated with proton radiosurgery were selected due to the small target volume. Dose distributions were compared for RBE-weighted and RBE-fixed. The impact of RBE was assessed using Monte Carlo (MC) dose calculations for stereotactic doses and doses of 2 Gy(RBE). Four different α/ß ratios were investigated. Additionally, dose distributions were recalculated with reduced range margins. Applying variable RBE values for stereotactic doses resulted in an increase in the mean dose of 1.6% for a low α/ß of 2 Gy, but a decrease of 2.6% for an α/ß of 10 Gy. However, the mean dose increased to 17.1% and 2.1% for doses of 2 Gy(RBE) and α/ß of 2 Gy and 10 Gy, respectively. Reducing range margins from 3.5% + 1 mm to 2.5% + 1 mm resulted in negligible difference in the mean RBE within the target, or 0.1% for stereotactic doses and 0.3% for doses of 2 Gy(RBE). Larger differences were seen for a range reduction to 0% + 1 mm, i.e. 1.1% and 3.0% for stereotactic doses and doses of 2 Gy(RBE), respectively. Because potential RBE effects are typically more pronounced in the distal part of a field, a bigger clinical impact of RBE uncertainties in small fields is expected. Our study shows that this could be significant for tissues with low α/ß and a small dose per fraction. The uncertainty in RBE due to the uncertainty associated with the α/ß ratio seems larger than the impact of the applied range uncertainty margin on RBE.

State of the Union in Open Neurovascular Training.

BACKGROUND: The evolution of minimally invasive endovascular approaches and training paradigms has reduced open neurovascular case exposure for neurosurgical residents. There are no published estimates of open neurovascular case volumes during residency or Committee on Advanced Subspecialty Training (CAST) accredited fellowships. METHODS: Case volumes from residency programs submitting data for CAST accredited fellowship applications were collected and analyzed. The study period covered the academic years of 2013-2016. Case index volumes were calculated to provide an estimate of total volume of cases each trainee participated in a given year. The case index volume was defined as the total volume of cases per year divided by the total training complement. RESULTS: Over the study period, institutional data from 46 programs were available. Of those programs, 9 programs had CAST accredited open cerebrovascular fellowships. Across all 46 programs, the median number of vascular cases was 246 (interquartile range [IQR]: 148-340), whereas the median number of open vascular cases was 105 (IQR: 67-152). The median number of open aneurysm cases among programs with CAST cerebrovascular fellowships was 80 (IQR: 54-103) and among programs without CAST cerebrovascular fellowships was 34 (IQR: 24-63). The median open aneurysm case index volume for trainees at programs with and without CAST cerebrovascular fellowships was 23 (IQR: 14-29) and 19 (IQR: 11-24). CONCLUSIONS: Strong neurovascular training can be obtained through dedication and planning. Completion of a CAST accredited cerebrovascular fellowship will often more than double aneurysm case exposure of trainees.

Jaw Immobilization for Gamma Knife Surgery in Patients with Mandibular Lesions: A Newly, Innovative Approach.

BACKGROUND: The purpose of our report is to describe an innovative system used for mandibular immobilization during Gamma Knife surgery (GKS) procedures. It is based on an approach originally developed in Marseille in extracranial lesions, close to or involving the mandible, which may imply a certain degree of movement during the therapeutic image acquisitions and/or GKS treatment. METHODS: The maxillofacial surgeon applied bone titanium self-tapping monocortical screws (4; 2 mm diameter, 10 mm length) between roots of the teeth in the fixed gingiva (upper and lower maxillae) the day before GKS (local anesthesia, 5-10 min time). Two rubber bands were sufficient for the desired tension required to undergo GKS. We further proceeded with application of the Leksell stereotactic G frame and carried out the usual GKS procedure. RESULTS: The mean follow-up period was 2.3 years (range 0.6-3). Three patients have been treated with this approach: 2 cases with extracranial trigeminal schwannomas involving the mandibular branch, with decrease in tumor size on MR follow-up; 1 case with residual paracondylian mandibular arteriovenous malformation following partial embolization, completely obliterated at 7 months (digital subtraction angiography programmed 1 year after treatment). CONCLUSIONS: Jaw immobilization appears to be a quick, minimally invasive, safe and accurate adjunctive technique to enhance GKS targeting precision.

Three-dimensional CT angiography for the diagnosis and assessment of arteriovenous malformations in the oral and maxillofacial region.

OBJECTIVE: The purpose of this study was to evaluate the diagnostic performance of three-dimensional computed tomography angiography (3D-CTA) for arteriovenous malformations (AVMs) in the oral and maxillofacial region. MATERIALS AND METHODS: Sixty four-slice spiral CT angiography of oral or maxillofacial region was performed in 8 patients with surgically proven arteriovenous malformations. The morphologic features, size, location, boundary, and feeding and draining vessels of lesions were reviewed. RESULTS: AVMs in 5 patients were located in the soft tissues and 3 were in the mandible. CTA of all cases showed tangles of disorganized vessels with well-defined borders. The feeding and draining vessels were enlarged and tortuous. Four patients had bone involvement. CONCLUSION: Sixty four-slice spiral CTA can accurately demonstrate the morphological characteristics of AVMs.

Treatment of arteriovenous malformations: assessment of 2 techniques--transmandibular curettage versus resection and immediate replantation.

PURPOSE: This study evaluates 2 surgical methods used at our center for the treatment of mandibular arteriovenous malformations (AVMs): resection with immediate replantation and curettage via proximal transmandibular osteotomy. PATIENTS AND METHODS: Patients with AVMs of the mandible who were treated during a 17-year period between 1992 and 2008 at our department were assessed. Two surgical techniques were used for treatment: 1) resection of the segment, curettage of the intrabony lesion, extraction of involved teeth, and immediate replantation and 2) proximal osteotomy curettage of the lesion within the bone and extraction of involved teeth. In the replantation group the resected segment of the mandible was replanted after the contents were scraped out and the involved teeth removed. In contrast, in the proximal osteotomy group this was done without removal of the bone segment. In both techniques the cortical bone of the mandible was maintained. However, in the transmandibular curettage group the periosteum was not entirely stripped off because curettage was done via proximal osteotomy without removal of the segment. The entire intrabony lesion and a margin of cancellous bone related to the lesion were excised in both groups. The bone was fixed with titanium plates in all cases. All patients were followed up annually for a period of 1 to 17 years (mean, 9.5 years). RESULTS: We treated 12 patients with mandibular AVMs (2 male and 10 female patients). Their ages ranged from 7 to 17 years. Preoperative angiography showed high-flow central vascular lesions in all patients. Of the lesions, 7 (58%) were treated via resection with immediate replantation and 5 (42%) were treated via transmandibular curettage. Embolization was performed in 4 cases 48 hours before surgery. However, blood loss was not significantly decreased by embolization. The lesions were categorized as multilocular (58.3%) or unicystic (41.7%) based on the radiographic findings and were located in the mandibular body (66.7%) or ramus (33.3%). Blood loss averaged 1.60 L in the group undergoing resection and immediate replantation and 1.30 L in the transmandibular curettage group. During the follow-up period, no recurrences were encountered in either group via clinical, radiographic, or computed tomography scan assessment, and none of the patients had facial deformities develop. CONCLUSIONS: The results suggest that transmandibular curettage via proximal osteotomy without complete resection is an effective less invasive method with which to treat AVMs of the mandible provided that the lesion is small, is confined within the bone, and has not invaded the soft tissues. Less blood loss, preservation of the bone, more favorable postoperative esthetics, and better function are among the advantages of this technique. In more extensive cases and those involving both hard and soft tissues, resection with immediate replantation is recommended. Both techniques obviated the need for bone graft reconstruction. This technique is better than resection and discarding of the segment.

Hemodynamic assessment of the spinal cord arteriovenous malformation with intraoperative microvascular Doppler ultrasound: case report.

Microvascular Doppler recordings were taken from the nidus and draining system of a dural spinal cord arteriovenous malformation during operative treatment. Doppler signals readily showed the direction of blood flow in the draining vein and the hemodynamic effects of surgical maneuvers. Recording during alterations of mean arterial blood pressure and partial carbon dioxide pressure (pCO2) demonstrated lack of autoregulation and impaired CO2 reactivity in the AVM nidus. Microvascular Doppler techniques provide useful intraoperative assessment of the hemodynamics of arteriovenous malformations of the spinal cord.

Decision analysis: a tool of the future: an application to unruptured arteriovenous malformations.

Overwhelming and confusing data regarding the natural history of arteriovenous malformations can confound physicians attempting to advise patients whether surgery of unruptured arteriovenous malformations is indicated. Decision analysis is a new mathematical tool that allows physicians to compare options in such patients. With the use of a simple office computer, a software program was devised to compare surgical versus conservative options in a hypothetical 25-year-old man. The computer model weighs the important considerations of patient age, mortality and morbidity rates of the physician performing the surgery, rebleeding from the arteriovenous malformation, and patient desires, using the Markov process. When mortality and morbidity rates are reasonable, the mathematical process supports surgical intervention in the hypothetical patient. Patient guidelines for older patients and future plans for the model using grading systems are discussed.