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Vivien Chan, Alessandro Marro, Jeremy Rempel and Andrew Nataraj

OBJECTIVE

In this study the authors sought to compare the proportion of patients with lumbar spondylolisthesis detected to have dynamic instability based on flexion and extension standing radiographs versus neutral standing radiograph and supine MRI.

METHODS

This was a single-center retrospective study of all consecutive adult patients diagnosed with spondylolisthesis from January 1, 2013, to July 31, 2018, for whom the required imaging was available for analysis. Two independent observers measured the amount of translation, in millimeters, on supine MRI and flexion, extension, and neutral standing radiographs using the Meyerding technique. Interobserver and intraobserver correlation coefficients were calculated. The difference in amount of translation was compared between 1) flexion and extension standing radiographs and 2) neutral standing radiograph and supine MRI. The proportion of patients with dynamic instability, defined as a ≥ 3 mm difference in the amount of translation measured on different imaging modalities, was reported. Correlation between amount of dynamic instability and change in back pain and leg pain 1 year after decompression and instrumented fusion was analyzed using multivariate regression analysis.

RESULTS

Fifty-six patients were included in this study. The mean patient age was 57.1 years, and 55.4% of patients were female. The most commonly affected levels were L4–5 (60.7%) and L5–S1 (30.4%). The average translations measured on flexion standing radiograph, extension standing radiograph, neutral standing radiograph, and supine MRI were 12.5 mm, 11.9 mm, 10.1 mm, and 7.2 mm, respectively. The average difference between flexion and extension standing radiographs was 0.58 mm, with dynamic instability detected in 21.4% of patients. The average difference between neutral standing radiograph and supine MRI was 3.77 mm, with dynamic instability detected in 60.7% of patients. The intraobserver correlation coefficient ranged from 0.77 to 0.90 mm. The interobserver correlation coefficient ranged from 0.79 to 0.86 mm. In 44 patients who underwent decompression and instrumented fusion, the amount of dynamic instability between standing and supine imaging was significantly correlated with change in back pain (p < 0.001) and leg pain (p = 0.05) at the 12-month postoperative follow-up. There was no correlation between amount of dynamic instability between flexion and extension standing radiographs and postoperative back pain and leg pain.

CONCLUSIONS

More patients were found to have dynamic instability by using neutral standing radiograph and supine MRI. In patients who received decompression and instrumented fusion, there was a significant correlation between dynamic instability on neutral standing radiograph and supine MRI and change in back pain and leg pain at 12 months.

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Mitchell P. Wilson, Cian O’Kelly, Andrew S. Jack and Jeremy Rempel

OBJECTIVE

Freehand insertion of external ventricular drains (EVDs) using anatomical landmarks is considered the primary method for placement, although alternative techniques have shown improved accuracy in positioning. The purpose of this study was to retrospectively evaluate which features of the baseline clinical history and preprocedural CT scan predict EVD positioning into suboptimal and unsatisfactory locations when using the freehand insertion technique.

METHODS

A retrospective chart review was performed evaluating 189 consecutive adult patients who received an EVD via freehand technique through an anterior burr hole between January 1, 2014, and December 31, 2015, at a Level 1 trauma facility in Edmonton, Alberta, Canada. The primary outcome measures included features associated with suboptimal positioning (Kakarla grade 1 vs Kakarla grades 2 and 3). The secondary outcome measures were features associated with unsatisfactory positioning (Kakarla grades 1 and 2 vs Kakarla grade 3).

RESULTS

Fifty-one EVDs (27%) were suboptimally positioned. Fifteen (8%) EVDs were placed into eloquent cortex or nontarget CSF spaces. Admitting diagnosis, head height-to-width ratio in axial plane, and side of predominant pathology were found to be significantly associated with suboptimal placement (p = 0.02, 0.012, and 0.02, respectively). A decreased height-to-width ratio was also associated with placement into only eloquent cortex and/or nontarget CSF spaces (p = 0.003).

CONCLUSIONS

Freehand insertion of an EVD is associated with significant suboptimal positioning into parenchyma and nontarget CSF spaces. The likelihood of inaccurate EVD placement can be predicted with baseline clinical and radiographic features. The patient’s height-to-width ratio represents a novel potential radiographic predictor for malpositioning.

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Tim E. Darsaut, Robert Fahed, R. Loch Macdonald, Adam S. Arthur, M. Yashar S. Kalani, Fuat Arikan, Daniel Roy, Alain Weill, Alain Bilocq, Jeremy L. Rempel, Michael M. Chow, Robert A. Ashforth, J. Max Findlay, Luis H. Castro-Afonso, Miguel Chagnon, Guylaine Gevry and Jean Raymond

OBJECTIVE

Ruptured intracranial aneurysms (RIAs) can be managed surgically or endovascularly. In this study, the authors aimed to measure the interobserver agreement in selecting the best management option for various patients with an RIA.

METHODS

The authors constructed an electronic portfolio of 42 cases of RIA in which an angiographic image along with a brief clinical vignette for each patient were displayed. Undisclosed to the responders was that the RIAs had been categorized as International Subarachnoid Aneurysm Trial (ISAT) (small, anterior-circulation, non–middle cerebral artery location, n = 18) and non-ISAT (n = 22) aneurysms; the non-ISAT group also included 2 basilar apex aneurysms for which a high number of endovascular choices was expected. The portfolio was sent to 132 clinicians who manage patients with RIAs and circulated to members of an American surgical association. Judges were asked to choose between surgical and endovascular management, to indicate their level of confidence in the choice of treatment on a quantitative 0–10 scale, and to determine whether they would include the patient in a randomized trial in which both treatments are compared. Eleven clinicians were asked to respond twice at least 1 month apart. Responses were analyzed using kappa statistics.

RESULTS

Eighty-five clinicians (58 cerebrovascular surgeons, 21 interventional neuroradiologists, and 6 interventional neurologists) answered the questionnaire. Overall, endovascular management was chosen more frequently (n = 2136 [59.8%] of 3570 answers). The proportions of decisions to clip were significantly higher for non-ISAT (50.8%) than for ISAT (26.2%) aneurysms (p = 0.0003). Interjudge agreement was only fair (kappa 0.210, 95% CI 0.158–0.276) for all cases and judges, despite high confidence levels (mean score > 8 for all cases). Agreement was no better within subgroups of clinicians with the same specialty, years of experience, or location of practice or across capability groups (ability to clip or coil, or both). When agreement was defined as > 80% of responders choosing the same option, agreement occurred for only 7 of 40 cases, all of which were ISAT aneurysms, for which coiling was preferred.

CONCLUSIONS

Agreement between clinicians regarding the best management option was infrequent but centered around coiling for some ISAT aneurysms. Surgical clipping was chosen more frequently for non-ISAT aneurysms than for ISAT aneurysms. Patients with such an aneurysm might be candidates for inclusion in randomized trials.