Diego San Millán Ruíz and Dheeraj Gandhi
Dheeraj Gandhi, Sameer A. Ansari, B. Gregory Thompson and Cormac Maher
Traumatic injuries of the posterior communicating artery are distinctly rare. We report an unusual case of traumatic tear of the posterior communicating artery with fistulous communication to the adjacent, retroclival venous plexus. The fistula, and an accompanying large venous aneurysm, was completely occluded via transvenous embolization. The patency of the posterior communicating artery was preserved.
Ajay Malhotra, Xiao Wu, Timothy Miller, Charles C. Matouk, Pina Sanelli and Dheeraj Gandhi
Both endovascular coiling and the Pipeline embolization device (PED) have been shown to be safe and clinically effective for treatment of small (< 10 mm) aneurysms. The authors conducted a comparative effectiveness analysis to compare the utility of these treatment methods in terms of health benefits.
A decision-analytical study was performed with Markov modeling methods to simulate patients with small unruptured aneurysms undergoing endovascular coiling, stent-assisted coiling (SAC), or PED placement for treatment. Input probabilities were derived from prior literature, and 1-way, 2-way, and probabilistic sensitivity analyses were performed to assess model and input parameter uncertainty.
The base case calculation for a 50-year-old man reveals PED to have a higher health benefit (17.48 quality-adjusted life years [QALYs]) than coiling (17.44 QALYs) or SAC (17.36 QALYs). PED is the better option in 6020 of the 10,000 iterations in probabilistic sensitivity analysis. When the retreatment rate of PED is lower than 9.53%, and the coiling retreatment is higher than 15.6%, PED is the better strategy. In the 2-way sensitivity analysis varying the retreatment rates from both treatment modalities, when the retreatment rate of PED is approximately 14% lower than the retreatment rate of coiling, PED is the more favorable treatment strategy. Otherwise, coiling is more effective. SAC may be better than PED when the unfavorable outcome risk of SAC is lower than 70% of its reported current value.
With the increasing use of PEDs for treatment of small unruptured aneurysms, the current study indicates that these devices may have higher health benefits due to lower rates of retreatment compared to both simple coiling and stent-assisted techniques. Longer follow-up studies are needed to document the rates of recurrence and retreatment after coiling and PED to assess the cost-effectiveness of these strategies.
Randall Schultz Jr., Andrew Steven, Aaron Wessell, Nancy Fischbein, Charles A. Sansur, Dheeraj Gandhi, David Ibrahimi and Prashant Raghavan
Dorsal arachnoid webs (DAWs) and spinal cord herniation (SCH) are uncommon abnormalities affecting the thoracic spinal cord that can result in syringomyelia and significant neurological morbidity if left untreated. Differentiating these 2 entities on the basis of clinical presentation and radiological findings remains challenging but is of vital importance in planning a surgical approach. The authors examined the differences between DAWs and idiopathic SCH on MRI and CT myelography to improve diagnostic confidence prior to surgery.
Review of the picture archiving and communication system (PACS) database between 2005 and 2015 identified 6 patients with DAW and 5 with SCH. Clinical data including demographic information, presenting symptoms and neurological signs, and surgical reports were collected from the electronic medical records. Ten of the 11 patients underwent MRI. CT myelography was performed in 3 patients with DAW and in 1 patient with SCH. Imaging studies were analyzed by 2 board-certified neuroradiologists for the following features: 1) location of the deformity; 2) presence or absence of cord signal abnormality or syringomyelia; 3) visible arachnoid web; 4) presence of a dural defect; 5) nature of dorsal cord indentation (abrupt “scalpel sign” vs “C”-shaped); 6) focal ventral cord kink; 7) presence of the nuclear trail sign (endplate irregularity, sclerosis, and/or disc-space calcification that could suggest a migratory path of a herniated disc); and 8) visualization of a complete plane of CSF ventral to the deformity.
The scalpel sign was positive in all patients with DAW. The dorsal indentation was C-shaped in 5 of 6 patients with SCH. The ventral subarachnoid space was preserved in all patients with DAW and interrupted in cases of SCH. In no patient was a web or a dural defect identified.
DAW and SCH can be reliably distinguished on imaging by scrutinizing the nature of the dorsal indentation and the integrity of the ventral subarachnoid space at the level of the cord deformity.
Aaron P. Wessell, Matthew J. Kole, Gregory Cannarsa, Jeffrey Oliver, Gaurav Jindal, Timothy Miller, Dheeraj Gandhi, Gunjan Parikh, Neeraj Badjatia, E. Francois Aldrich and J. Marc Simard
The authors sought to evaluate whether a sustained systemic inflammatory response was associated with shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage.
A retrospective analysis of 193 consecutive patients with aneurysmal subarachnoid hemorrhage was performed. Management of hydrocephalus followed a stepwise algorithm to determine the need for external CSF drainage and subsequent shunt placement. Systemic inflammatory response syndrome (SIRS) data were collected for all patients during the first 7 days of hospitalization. Patients who met the SIRS criteria every day for the first 7 days of hospitalization were considered as having a sustained SIRS. Univariate and multivariate regression analyses were used to determine predictors of shunt dependence.
Sixteen percent of patients required shunt placement. Sustained SIRS was observed in 35% of shunt-dependent patients compared to 14% in non–shunt-dependent patients (p = 0.004). On multivariate logistic regression, female sex (OR 0.35, 95% CI 0.142–0.885), moderate to severe vasospasm (OR 3.78, 95% CI 1.333–10.745), acute hydrocephalus (OR 21.39, 95% CI 2.260–202.417), and sustained SIRS (OR 2.94, 95% CI 1.125–7.689) were significantly associated with shunt dependence after aneurysmal subarachnoid hemorrhage. Receiver operating characteristic analysis revealed an area under the curve of 0.83 for the final regression model.
Sustained SIRS was a predictor of shunt-dependent hydrocephalus following aneurysmal subarachnoid hemorrhage even after adjustment for potential confounding variables in a multivariate logistic regression model.
Timothy R. Miller, Sijia Guo, Elias R. Melhem, Howard M. Eisenberg, Jiachen Zhuo, Nathaniel Kelm, Mor Dayan, Rao P. Gullapalli and Dheeraj Gandhi
Magnetic resonance–guided focused ultrasound (MRgFUS) ablation of the globus pallidus interna (GPi) is being investigated for the treatment of advanced Parkinson’s disease symptoms. However, GPi lesioning presents unique challenges due to the off-midline location of the target. Furthermore, it remains uncertain whether intraprocedural MR thermometry data can predict final lesion characteristics.
The authors first performed temperature simulations of GPi pallidotomy and compared the results with those of actual cases and the results of ventral intermediate nucleus (VIM) thalamotomy performed for essential tremor treatment. Next, thermometry data from 13 MRgFUS pallidotomy procedures performed at their institution were analyzed using 46°C, 48°C, 50°C, and 52°C temperature thresholds. The resulting thermal models were compared with resulting GPi lesions noted on postprocedure days 1 and 30. Finally, the treatment efficiency (energy per temperature rise) of pallidotomy was evaluated.
The authors’ modeled acoustic intensity maps correctly demonstrate the elongated, ellipsoid lesions noted during GPi pallidotomy. In treated patients, the 48°C temperature threshold maps most accurately predicted postprocedure day 1 lesion size, while no correlation was found for day 30 lesions. The average energy/temperature rise of pallidotomy was higher (612 J/°C) than what had been noted for VIM thalamotomy and varied with the patients’ skull density ratios (SDRs).
The authors’ acoustic simulations accurately depicted the characteristics of thermal lesions encountered following MRgFUS pallidotomy. MR thermometry data can predict postprocedure day 1 GPi lesion characteristics using a 48°C threshold model. Finally, the lower treatment efficiency of pallidotomy may make GPi lesioning challenging in patients with a low SDR.
Jason Mackey, Robert D. Brown Jr., Charles J. Moomaw, Laura Sauerbeck, Richard Hornung, Dheeraj Gandhi, Daniel Woo, Dawn Kleindorfer, Matthew L. Flaherty, Irene Meissner, Craig Anderson, E. Sander Connolly, Guy Rouleau, David F. Kallmes, James Torner, John Huston III and Joseph P. Broderick
Familial predisposition is a recognized nonmodifiable risk factor for the formation and rupture of intracranial aneurysms (IAs). However, data regarding the characteristics of familial IAs are limited. The authors sought to describe familial IAs more fully, and to compare their characteristics with a large cohort of nonfamilial IAs.
The Familial Intracranial Aneurysm (FIA) study is a multicenter international study with the goal of identifying genetic and other risk factors for formation and rupture of IAs in a highly enriched population. The authors compared the FIA study cohort with the International Study of Unruptured Intracranial Aneurysms (ISUIA) cohort with regard to patient demographic data, IA location, and IA multiplicity. To improve comparability, all patients in the ISUIA who had a family history of IAs or subarachnoid hemorrhage were excluded, as well as all patients in both cohorts who had a ruptured IA prior to study entry.
Of 983 patients enrolled in the FIA study with definite or probable IAs, 511 met the inclusion criteria for this analysis. Of the 4059 patients in the ISUIA study, 983 had a previous IA rupture and 657 of the remainder had a positive family history, leaving 2419 individuals in the analysis. Multiplicity was more common in the FIA patients (35.6% vs 27.9%, p < 0.001). The FIA patients had a higher proportion of IAs located in the middle cerebral artery (28.6% vs 24.9%), whereas ISUIA patients had a higher proportion of posterior communicating artery IAs (13.7% vs 8.2%, p = 0.016).
Heritable structural vulnerability may account for differences in IA multiplicity and location. Important investigations into the underlying genetic mechanisms of IA formation are ongoing.